Abstracts

Abstracts

1 GENERAL ANALYTICAL CHEMISTRY

1.i Fundamentals, methods, apparatus, reagents, automation, data processing

Updating a vintage ICP atomic-emission spectrometer. R.I. Botto. Verff. beschreiben den Einsatz eines schon 1976 angeschafften ICP-

AES-Systems im Analytischen Forschungslabor der Exxon Comp., Bay- town, TX (USA), einschlieNich der Verbesserungen, die fiber einen Zeit- raum yon 10 Jahren sowohl bei der Hardware als auch bei der Software vorgenommen wurden. Selbst bei der v611igen Neuorganisation des La- bors, bei der zunfichst ein modernes Ger/it neu angeschafft werden sollte, entschied man sich fiir eine Oberholung und Modernisierung des alten Ger/its. Die Griinde ffir diese Entscheidung werden angegeben. Hierbei werden einige recht interessante Aspekte fiir die Organisation eines solchen Labors diskutiert. - Talanta 37, 157-166 (1990). Exxon Res. & Engin. Comp., Bayton Spec. Prod., Bayton, TX (USA) W. Czysz

Dual-beam, light-scattering interferometry for simultaneous measurements of droplet-size and velocity distributions of aerosols from commonly used nebulizers. R.H. Clifford, I. Ishii, A. Montaser and C.A. Meyer.

Dual-beam, light-scattering interferometry is introduced for simultaneous measurement of droplet-size and droplet-velocity distributions. The technique was tested in the characterization of tertiary aerosols produced by five nebulization systems (a pneumatic, an ultrasonic, and three frit-type nebulizers) used in inductively coupled plasma spectrometry. In general, the Sauter mean diameter (D3,2) of tertiary aerosol produced by frit-type nebulizer was smaller than those of ultrasonic and pneumatic nebulizers. At higher injector gas flow, D3.2 was reduced for the pneumatic nebulizer but was increased for the ultrasonic nebulizer. At the same injector gas flow rate, droplets move slightly faster if helium is used as injector gas instead of argon. For all practical purposes, the D3.2 values measured for tertiary aerosol with dual-beam, light- scattering interferometry are comparable to the same data obtained by laser Fraunhofer diffraction. Compared to laser Fraunhofer diffraction, the proposed technique possesses two unique advantages. First, droplet velocity distribution can be measured. Second, spatially resolved information on droplet-size and velocity distributions may be obtained directly and rapidly. - Anal. Chem. 62, 390-394 (1990). Dept. Chem., George Washington Univ., Washington, D.C. (USA)

Generatoren in der ICP-Spektroskopie. R. Ender. Das Philips PU 7450 ICP-System verf/igt fiber eine toroidale ICP-

Fackel (lfingere Verweilzeiten und h6here Temperaturen als bei ellipsoi- dem Plasma) und einen freilaufenden Flagg-Oszillator yon 40,68 MHz oder h6her (gegenfiber 27-MHz-Plasmen um den Faktor 3 bis t 5 verbes- serte Nachweisgrenze, geringerer Ar-Verbrauch) bei freiwS~hlbarer Lei- stung im Bereich 0 ,7-2,0 kW, wodurch bessere M6glichkeiten fiir die Optimierung der Analysen gegeben sind. LaborPraxis 13(10), 852 - 856 (1989). Philips GmbH, Kassel (D) W. Schmidt

A new continuous hydride generator for ICP-AES. G. Vujicic and I. Steffan.

With the construction of a tubular hydride generator some of the technical inconveniences of the hydride generation technique are overcome. The system allows the determination of hydride forming elements and mercury with a sample uptake rate of 1 ml/min without loss of sensitivity. Due to the small volume of the reactor and the performed neutralization of the reaction mixture in the siphon the memory effect is reduced. The sodium hydroxide used for neutralization also prevents the generation of an excess of hydrogen and therefore removes its negative influence on the plasma discharge. - Mikrochim. Acta 1989, III, 267--272. IWM, Glattbrugg (CH); Inst. Anal. Chem., Univ., Wien (A)

Energy transport in the inductively coupled plasma. D.A. Rodham, J.K. Shurtleff and P.B. Farnsworth.

Time- and space-resolved electron density measurements, made both above the load coil and in the load coil region of a pulsed inductively coupled plasma, are presented. These data, coupled with argon and calcium emission data, give values for the rates of both radial and vertical transport in the plasma. The data indicate that analyte emission behavior is governed primarily by the rate at which the central channel can be heated through radial transport processes. The electron densities measured in the load coil region agree well with electron densities calculated by models assuming local thermodynamic equilibrium, but agree poorly with non-equilibrium models. Some of the time-dependent emission behavior observed in previous work with modulated plasmas is explained by non-uniform heating of argon in the load coil region. - Mikrochim. Acta 1989, III, 187-195. Dept. Chem., Brigham Young Univ., Provo, UT (USA)

Rotational temperatures and LTE in argon ICP. P.A. Abila and C. Trassy. Rotational temperatures deduced from OH molecular spectra have

been studied in an analytical argon inductively coupled plasma for various operating conditions. The Boltzmann plots are often curved and temperatures are very different from those deduced from atomic Boltzmann plots or from other molecular species like Nz. Generally non- equilibrium is deduced from these observations. But thermal stability of OH and local gradient in the droplet surroundings can to a great part explain these phenomena. Complex simulations seem useful for a satisfactory explanation. - Mikrochim. Acta 1989, III, 159-168. Lab. Physicochim. Ind., Inst. Nat. Sci. Appl. Lyon, Villeurbanne (F)

On the matrix effects on spectral lines intensity during excitation in arc double plasma jet. E.V. Smirnova, S.B. Golovko and V.K. Chikalina.

Man untersuchte den Einflul3 der Matrixwirkung auf die Intcnsitfit yon Spektrallinien der mittels AES zu bestimmenden Elemente; gearbeitet wurde mit dem zweistrahligen Bogenplasmatron in Ar-Atmosphfire (cf. V.S. Engel'sht et al.: Zavod. Lab. 42, 174 (1976)); der Bogen wird mit Hilfe des Gleichstromgleichrichters (Spannung 300 V, Strom 90 A) gespeist. Zu diesem Zweck werden ~ 150 nag feinzermahlene Probe (Partikelgr6ge 0,074 ram) in einen kleinen Plexiglaszylinder (Durchmes- ser 1,5 cm, H6he 4,0 cm) geftillt und in Form der Aerosuspension durch Ar-Strom (0,8 1/min) zu der Verbindungsstelle mit dem das Plasma bildenden Ar-Strom (3,6 l/rain) transportiert. Die optimale Aufnahme- zone der Spektren befindet sich in einer Entfernung von 16 mm yon der erwfihnten Verbindungsstelle. Auf die beschriebene Weise stellte man den Einflul3 yon Na (in Form von NaCI) und Ca auf die Verdampfung yon pulverigen geologischen Proben (Quarzit, Granit, Kalzit) bei der Bestimmung yon La, Tin, Fe, Nb, Sc u.a. lest. Na und weniger auch Ca beeinflussen gfinstig die Intensit/it yon Spektrallinien der zu bestimmenden Elemente, was mittels der Methode des Lokalgleichgewichts bestfitigt wurde. Fe und fihnlich auch Ti erniedrigen dagegen die Intensitfit der Spektrallinien der in den genannten geologischen Proben zu bestimmenden Elemente. Man diskutiert ausftihrlich den Mechanismus der Beeinflussung yon AES-Spektrallinienintensitfit durch die erw~ihnten Zus/itze unter Anwendung der beschriebenen Technik. -- Zh. Anal. Khim. 44, 2028 --2036 (1989) (Russisch, mit engl. Zus.fass.). Vinogradov Inst. Geochem., Akad. Wiss., Irkutsk (SU) F. Jancik

Basic investigations for laser microanalysis: I. Optical emission spectrometry of laser-produced sample plumes. F. Leis, W. Sdorra, J. Bak Ko and K. Niemax.

In order to find optimum conditions for laser ablation and atomization for analytical purposes, time resolved emission spectra ofNd: YAG laser- produced plasma plumes propagating into noble gas atmospheres of different pressures were measured with an optical multichannel analyzer. The time evolution of the plasma temperature was determined. Strong

1.1 Fundamentals, methods, apparatus, reagents, automation, data processing 647

temperature changes were observed depending on the matrix composition. The analytical figures of merit of optical emission spectrometry (OES) of laser-produced sample plasmas were determined using, as examples, measurements of two analytes (silicon and chromium) in homogeneous and low-alloyed standard steel samples. - Mikrochim. Acta 1989, II, 185-199. Inst. Spektrochem. Angew. Spektrosk. (ISAS), Dortmund (D)

Basic investigations for laser microanalysis: II. Laser-induced fluorescence in laser-produced sample plumes. W. Sdorra, A. Quentmeier and K. Niemax.

Laser-induced fluorescence in laser-ablated standard steel samples was measured, in order to study the atomization and propagation properties of the plasma plume and the analytical figures of merit of the method. As an example, measurements were performed exciting silicon, chromium or boron atoms by pulsed dye laser radiation. - Mikrochim. Acta 1989, II, 201- 218. Inst. Spektrochem. Angew. Spektrok. (ISAS), Dortmund (D)

Analytical applications of laser-enhanced ionization spectrometry in flames and furnaces. O. Axner, H. Rubinsztein-Dunlop and S. Sj6strfm.

This paper is concerned with a critical analysis of the analytical performance of laser-enhanced ionization (LEI) spectrometry in flames and furnaces as an ultra-sensitive trace-element technique. Updated tables of LEI detection limits, both in flames and furnaces, are given. Special attention is paid to interference phenomena which are unique to the LEI technique. Ways of reducing their influence on the analytical signals are proposed. Finally, advantages and disadvantages of LEI spectrometry as a tool for ultra-sensitive trace element analysis are discussed. - Mikrochim. Acta 1989, llI, 197-2~4. Dept. Physics, Chalmers Univ. Technol., Univ., G6teborg (S)

Pulsed and transient modes of atomization by cathodic sputtering in a glow discharge for atomic absorption spectrometry. C.L. Chakrabarti, K.L. Headrick, J.C. Hutton, Z. Bicheng, P.C. Bertels and M.H. Back.

Analytical applications of cathodic sputtering in a glow discharge have almost wholly involved the production of a steady-state atomic vapor from a bulk solid. Kinetic limitations result in relatively poor sensitivity and limit of detection for the steady-state mode of atomization. A method that overcomes these limitations, using the rapid production of analyte atoms to produce a greater transient concentration of atoms in the analysis volume than is possible for the steady-state mode of atomization, is described in this paper. Two new modes of atomization are presented. The transient mode of atomization uses a high-power discharge for the rapid production of analyte atoms, whereas the pulsed mode of atomization uses a discharge of much shorter duration and higher power to achieve even faster atomization than is possible with the transient mode of atomization. Since both the pulsed and the transient mode of atomization are based on faster production of analyte atoms and differ in that in the former a short (milliseconds) duration discharge is used, whereas in the latter a long (seconds) duration discharge is used, they are treated together as a new analytical technique. The sensitivity of the new analytical technique is, in some cases, similar to or greater than that of graphite furnace AAS. Factors affecting the sensitivity and areas for future improvement are discussed. - Anal. Chem. 62, 574-586 (1990). Dept. Chem., Carleton Univ., Ottawa, Ontario (CDN)

Long path atomic/ionic absorption spectrometry in an inductively coupled plasma. M.A. Mignardi, B.W. Smith and J.D. Winefordner.

A novel approach was taken to increase the atomic/ionic absorption path length in an ICP by using a water-cooled quartz "T-shaped" bonnet. Atomic and ionic absorption spectrometry was performed utilizing a continuum source and line sources. Absorption spectra of synthetic multielement solutions were collected with a photodiode array. Sample introduction into the ICP was accomplished with an ultrasonic nebulizer. To prevent the bonnet from cracking, low radio frequency powers were utilized (i.e., 400--600 W). Plasma diagnostics were performed to study the plasma temperature and electron number density within the "T- shaped" bonnet. Analytical figures of merit were found to be better than those obtained from previous work attempted with ICP-AAS and

approaching that of flame AAS. - Anal. Chem. 62, 586-592 (1990). Dept. Chem., Univ., Gainesville, FL (USA)

A system to study the effect of particle sizes in aerosols on the collection efficiency in impaction-electrothermal atomization spectrometry. J. Sneddon.

Verff. beschreiben anhand eines detaillierten Blockschemas den Auf- bau und die Arbeitsweise einer MeBbox zur qualitativen Untersuchung der Wirkung verschiedener trockener Aerosole (1 bis 120 ~tm) auf die Effizienz der Anreicherung eines einstuflgen Impactors, der einem elektrothermischen Atomisator vorgeschaltet ist. Bei einer konstanten Str6- mungsgeschwindigkeit yon 5 l/min, einem Dtisen6ffnungsdurchmesser von 1 mm und bei Verwendung einer nichtfiberzogenen Graphitoberfi/i- che wurden Partikel < 50 pm an der Auftreffoberflfiche gesammelt, Partikel > 85 [am nicht. Ferner wurde die Versuchsanordnung dadurch variiert, dal3 der Abstand Dfisen6ffnung-Auftreffoberfl/iche auf 2 mm und 8 mm eingestellt wurde. Dabei zeigte sieh, dal3 beim Abstand yon 8 mm eine Verbesserung der Sammlungseffizienz ffir Partikel > 50 pm erreicht wird. Die Untersuehung diente der Verbesserung der Effizienz eines im eigenen Labor entwickelten Impaction-elektrothermischen Atomabsorptionsspektrometers (J. Sneddon: Anal. Lett. 18, 1261 (1985); vgl. diese Z. 323, 649 (1986)). - Anal. Lett. 22, 2887-2893 (1989). Dept. Chem., Univ., Lowell, MA (USA) W. Czysz

Reverse flow injection analysis: Determination of trace amounts of metals using an on-line preconcentration technique. F. Esmadi, M. Kharoaf and A.S. Attiyat.

Determination of metal ion concentrations by reversed flow injection analysis using precipitation as a preconcentration technique is presented. The precipitate formed from the reaction of the cation and the anion, in a Tygon tube containing glass beads connected to the atomic absorption spectrophotometer, is dissolved by injection of a solution of a suitable dissolving reagent. The dissolving reagent dissolves the precipitate and the cation is transported to the atomic absorption spectrophotometer, yielding the signal. Three cations were tested to demonstrate the feasibility of the procedure: silver, calcium, and iron which were precipitated as silver chloride, calcium carbonate, and ferric hydroxide, respectively. Three dissolving reagents were investigated with silver chloride precipitate: ammonia, thiosulfate ion, and cyanide ion. Three other reagents were also used to dissolve ferric hydroxide precipitate: hydrochloric acid, phosphoric acid, and nitric acid. One reagent, hydrochloric acid, was used as a dissolving agent for calcium carbonate precipitate. Detection limits were 5 x 10 3, 4 x 10 -2, and 8 x 10 -~ ppm, respectively, for silver, iron, and calcium using thiosulfate, phosphoric acid, and hydrochloric acid as respective dissolving agents. The method could be applied easily to many routine analyses, such as water analysis due to its rapidity, precision, and small reagent consumption. - Microchem. J. 40, 277- 285 (1989). Chem. Dept., Yarmouk Univ., Irbid (JOR)

The standard addition and successive dilution method for evaluation and verification of results in atomic-absorption analysis. L. Pszonicki and W. Skwara.

Verff. beschreiben ein einfaches Verfahren zur Ermittlung und l]ber- prfifung der Ergebnisse von AAS-Analysen. Es erlaubt die Bestimmung richtiger Werte auch in Gegenwart starker unbekannter Stfrsubstanzen, ohne dab besondere Kenntnisse fiber die Zusammensetzung der Probe benftigt werden. Das Verfahrenskonzept geht aus von theoretischen Uberlegungen in bezug aufden Einfluf3 verschiedener Arten von St6run- gen auf die Form der Eichkurven. Man kann das Verfahren als eine Kombination yon Standardzugabe- und sukzessiver Verdfinnungsme- thoden bezeichnen. Obwohl es ffir die AAS entwickelt und erprobt wurde, scheint es auch ffir alle analytischen Techniken anwendbar zu sein, bei denen eine vorausgehende Eliminierung nichtspezifischer St6rsi- gnale, die unabhS, ngig vonder Analytkonzentration sind, m6glich ist. - Talanta 36, 1265--1276 (1989). Inst. Nucl. Chem. Technol., Warschau (PL) W. Czysz

Simultaneous multielement atomic-absorption analysis of biological materials. N.J. Miller-Ihli.

Zur Bestimmung einer Reihe von Elementen in verschiedenen Arten biologischen Materials wurde der Prototyp eines Multielement-Atomab-

648 1 General analytical chemistry

sorptionsspektrometers (SIMAAC = Simultaneous Multielement Atomic Absorption Spectrometer with a Continuum Source) eingesetzt. Er besteht im wesentlichen aus einer Kontinuum-Lichtquelle (300 W Cermax-Lampe (ILC Technol.)) und einem Echelle Polychromator (Spectraspan III (Beckman Instr.)), der ffir Wellenlfingen-Modulation modifiziert ist (durch eine an einem Galvanometer an der Innenseite des Eingangsspalts angebrachte Quarzplatte, angetrieben von einem Scan- steuerungsgerfit). Die Testanalysen wurden sowohl mit Flammen- als auch Graphitofen-Atomisierung durchgeftihrt. Ein Blockschema des SI- MAAC-Systems ist abgebildet. Analysenergebnisse sind in Tabellen angegeben. - Talanta 37, 119-125 (1990). U.S.D.A., Nutrient Composi- tion Lab., Beltsville, MD (USA) W. Czysz

Resolution of severely overlapped spectra from matrix-formated spectral data using constrained nonlinear optimization. S.L. Neal, E.R. Davidson and I.M. Warner.

A three-step scheme for resolving severely overlapped component spectra from bilinear matrix-formated data is reported. After the number of sample components is determined, a positive basis is first formed consisting of the most dissimilar rows and columns of the matrix. The concentration factor matrix (CFM) corresponding to this nonnegative, minimally correlated basis will be diagonal if the basis vectors happen to be feasible estimates of the component spectra. When the CFM is not diagonal, a constrained nonlinear optimization routine is used in a second step to reduce the off-diagonal elements of the CFM to zero while maintaining the nonnegativity of the estimated spectra. In many cases, the nonnegativity and feasibility constrains are not sufficient to produce a unique set of component spectra estimates. Other criteria, such as the degree of overlap of the resolved spectra, may be used as the basis of a third step to generate an arbitrary, but unique, choice among the feasible estimates of the component spectra. The performance of this scheme is evaluated by analyzing synthetic and experimental fluorescence excitation-emission matrices (EEMs) exhibiting various levels of spectra overlap and random noise. - Anal. Chem. 62, 658-664 (1990). Dept. Chem., Emory Univ., Atlanta, GA (USA)

Automated selection of library subsets for infrared spectral searching. J.M. Bjerga and G.W. Small.

A method for decreasing the time required to perform a standard library is described based on principal components analysis of infrared spectra. Principal components analysis calculates a new set of axes and coordinates which reduce the dimensionality of the original data space. Spectra are projected onto a principal plane where they are represented by a single point in a two-dimensional space. The angle of the point in the plane representing the unknown spectrum is determined, and only those library spectra with similar angles in the same plane are searched by use of the Euclidean distance metric. The principal components analysis was based on 2000 spectra in the EPA vapor phase infrared library. The plane angle procedure accurately selects a subset of spectra around the unknown which contains the 15-20 nearest matches as obtained by a previous Euclidean distance search of all 2000 spectra. The selection of the appropriate principal plane to use for a particular unknown spectrum is also discussed. The methodology is tested with intralibrary searches and with searches of laboratory data. - Anal. Chem. 62, 226-233 (i990). Dept. Chem., Univ. Iowa, Iowa City, IA (USA)

Combination of the Mahalanobis distance and residual variance pattern recognition techniques for classification of near-infrared reflectance spectra. N.K. Shah and P.J. Gemperline.

Principal component analysis of near-infrared reflectance (NIR) spectra is used for the calculation of Mahalanobis distances and for the construction of soft independent modeling of class analogy (SIMCA) classification models. The space spanned by the primary eigenvectors is used in the Mahalanobis distance classification and the space spanned by the secondary vectors is used in SIMCA residual variance classification. The complementary behavior of these two classification methods is discussed and a new classification rule based on a combination of the two methods is described. The application of NIR spectroscopy and the pattern recognition technique for identifying and classifying raw

materials used in pharmaceutical industry is also discussed. - Anal. Chem. 62, 465- 470 (1990). Dept. Chem., Univ., Greenville, NC (USA)

Locally weighted regression and scatter correction for near-infrared reflectance data. T. Naes, T. Isaksson and B. Kowalski.

This paper investigates the effect of multiplicative scatter correction (MSC) and nonlinear regression based on the first two and three principal components for near-infrared reflectance (NIR) spectroscopy data. The focus will be on linearity/nonlinearity as well as treatment of outliers. The main contribution of the paper is the presentation of and testing of a calibration method based on classification and local least-squares regression. The theory is illustrated by three examples from NIR analysis. The local linear calibration outperformed traditional methods in two of the examples. - Anal. Chem. 62, 664-673 (1990). Lab. Chemo- metrics, Univ., Seattle, WA (USA)

ATR-Spektroskopie im UV/VIS-Bereich - ProduktkontroUe. H. Schlem- met und J. Katzer.

Ein Gerfitekonzept zur ATR-Spektroskopie (ATR = attenuated total reflection = abgeschw/ichte Totalreflexion) wird vorgestellt, bei dem die eigentliche ATR-Sonde fiber flexible Lichtleiterfasern mit einem kom- pakten, schnell messenden Diodenzeilenspektrometer verbunden ist. Mit diesem Aufbau sind direkte Messungen an stark absorbierenden Proben (z.B. Extinktion 3000) ohne Verdiinnung m6glich. Ffir die verwendeten Sonden werden quantitative Angaben fiber die optimalen Extinktionsbe- reiche gemacht, die auch einen AnschluB an die Absorptionsspektrosko- pie erlauben. Es wird weiterhin gezeigt, daB die mit der ATR-Methode ermittelten Extinktionswerte fiber einen weiten Bereich linear vonder Konzentration abhfingen, wobei die erreichbare Reproduzierbarkeit bei etwa 0,1% liegt. Die Mel3geschwindigkeit kann bis zu 1000 Spektren pro Sekunde betragen. - GIT Fachz. Lab. 34, 257--263 (1990). Fa. Carl Zeiss, D-7082 Oberkochen R.H.S.

Two-beam thermal lens spectrometer for ultra-trace analysis. J. Shen and R.D. Snook.

Es wird ein Zweistrahl-Thermal-Lens-Gerfit vorgestellt, mit welchem hochempfindliche Ultraspurenmessungen yon Kupfer durchgeffihrt werden k6nnen. Dabei wird Cu(II) als [Cu(H20)6] 2+ bestimmt. Die mit Ethanol geffillte MeBzelle wird mit 5 x 10-5 tool/1 Cu(II)-L6sungen verwendet und die Absorption bei 800 nm gemessen. Die minimal nachweis- bare Menge (S/N=2) liegt bei 3,18 x 10 .9 ng Cu(II)/ml. Das Ger/it ist jedoch auch ffir die Analyse anderer Metalle einsetzbar. - Anal. Proc. 26, 403-405 (1989). DIAS UMIST, Manchester (GB) R.H.S.

Photoinitiation of peroxyoxalate chemiluminescence: application to flow injection analysis of chemilumophores. R.E. Milofsky and J.W. Birks.

Photoinitation of peroxyoxalate chemiluminescence is reported for the first time and applied to the detection of amino-substituted polycyclic aromatic hydrocarbons in flow injection analysis. This novel detection system is simplified by elimination of the reagent hydrogen peroxide used in most liquid-phase chemiluminescence detection schemes. Like the H202-initiated reaction, the sensitivity of detection in photoinitiated chemiluminescence (PICL) is enhanced by use of a base catalyst such as imidazole. Limits of detection are in the low- to mid-picogram range and are comparable to those obtained by fluorescence detection using the same apparatus. It is proposed that the PICL reaction begins with hydrogen abstraction by the triplet-excited state of the oxalate ester, followed by addition of 02. Subsequent steps in the mechanism proceed to form high-energy intermediates that transfer energy to the chemilumophore. - Anal. Chem. 62, 1050-1055 (1990). Dept. Chem. Biochem., Univ., Boulder, CO (USA)

Effects of inaccurate reference lifetimes on interpreting frequency-domain fluorescence data. K.S. Litwiler, J. Huang and F.V. Bright.

The effects of assigning inaccurate reference lifetimes in lifetime determinations are predicted theoretically by using standard equations. This theory leads to a method to remove reference error effects using common least-squares software. This method cannot, however, be used to deconvolute data collected with isochronal references. Uncorrected data can always be exactly solved with models containing one more degree of freedom than the true model. Monoexponential decays are fit by


double-exponential decays or excited-states processes. Unimodal distrib- uted decays often appear as discrete, double-exponential decays. - Anal. Chem. 62, 471-476 (1990). Dept. Chem., Acheson Hall, State Univ. New York, Buffalo, NY (USA)

Visible fluorescence spectrometry using second harmonic emission self- induced in semiconductor laser as a light source. T. Imasaka, T. Hiraiwa and N. Ishibashi.

Second harmonic emission (416 or 453 nm) self-induced in a near- infrared semiconductor laser (832 or 906 nm) is used as a light source for excitation of the fluorescent molecules which have absorption bands in the visible region. The conversion efficiency from fundamental to second harmonic emission is 1.7 x 10-11 (0.5 pW) for a continuous wave (CW) laser, when it is operated at 30 roW. This value is further improved for a pulsed laser operated at a peak power of 10 W. Perylene is used as a standard sample for construction of an analytical curve. The detection limit is 10- 6 M for CW laser excitation. The present fluorimetric system is used for measurements of pH dependance of the fluorescence intensity for 8-hydroxy-l,3,6-pyrenetrisulfonic acid (HPTS). Neutralization titration is demonstrated by using HPTS as a pH indicator. - Mikrochim. Acta 1989, II, 225--231. Fac. Engin., Kyushu Univ., Hakozaki, Fukuoka (J)

Precise relative ion abundances from Fourier transform ion cyclotron resonance magnitude-mode mass spectra. Z. Liang and A.G. Marshall.

The area under a correctly phased absorption-mode spectral peak is a direct measure of the number of oscillators (ions, spins, molecules) in Fourier transform spectrometry (ion cyclotron resonance, magnetic resonance, interferometry absorbance). However, phase correction can prove difficult when (as in broad-band Fourier transform ion cyclotron resonance (FT/ICR) detection is considerably time-delayed after excitation. In the absence of noise, Huang, Rempel, and Gross showed that a "complex area" method yields the correct absorption-mode peak area, for an unphased noiseless spectrum. In this paper, we show that the number of oscillators may also be obtained from a least-squares fit to a magnitude-mode (i.e., phase-independent) spectrum. In the presence of noise and in the absence of peak overlap, the magnitude-mode offers precision superior to that based on magnitude-mode peak height, "complex area", or even direct digital integration of a correctly phased absorption-mode peak, as demonstrated by both theoretical derivation and experimental FT/ICR results. The present method thus appears to offer the best available determination of the relative abundances of ions of different mass-to-charge ratio in FT/ICR mass spectrometry. - Anal. Chem. 62, 70-75 (1990). Dept. Chem., State Univ., Columbus, OH (USA)

Multipass cuvettes for spectrofluorimetry. N.L. Vekshin. Multiple-pass cuvettes which provide a 6-12-fold increase in the

sensitivity of spectrofluorimetric measurements are described. With these cuvettes, radiation losses by reflection and polarization are greatly decreased. The cuvettes can be placed directly into most commercial spectrofluorimeters. In the mirror cuvette, the exciting radiation is reflected by an aluminium or silver layer applied to the outer walls of the cuvette. In the cuvette based on total internal reflection, exciting radiation is reflected at the quartz/air boundaries of two attached prisms. Fluorescence spectra of rhodamine-B (I x 10 s M) in ethanol illustrate the enhancement obtained and the improved accuracy of measurements of fluorescent lifetimes. - Anal. Chim. Acta 227, 291 -295 (1989). Inst. Biol. Physics, Acad. Sciences U.S.S.R., Pushchino, Moscow Region (SU)

The proportional relationship between the efficiency of a DC ion source and atom mass. G. Ronan, J. Clark and N. Ketche11.

The efficiency of ion extraction from a DC ion source has been found by experiment to bear a close correlation to atomic mass. The factors influencing this efficiency are examined theoretically in terms of the mechanisms of extraction, that is, by gas flow, electric field and bulk diffusion. It is found that while charged material is extracted by the electric field, the transport mechanism to the region influenced by the extraction electrode is dominated by gas flow and is therefore dependent on atomic mass. Close agreement with theory and experiment can be seen. The practical application of this approximately linear dependence of ion yield and mass is demonstrated in the VG 9000 glow discharge mass spectrometer. The simple ratio of matrix ion current to contamination ion current gives a direct quantitative reading of weight-% impurity levels down to ppt levels. - Mikrochim. Acta 1989, Ill, 231- 237. VG Microtrace Ltd., Winsford, Cheshire (GB)

Nonionic surfactants used as exact mass internal standards for the 7 0 0 - 2100 dalton mass range in fast atom bombardment mass spectrometry. M.M. Siegel, R. Tsao, S. Oppenheimer and T.T. Chang.

Monosubstituted poly(ethylene glycol) and poly(propylene glycol) nonionic surfactant mixtures and isolated monosubstituted poly(ethyl- erie glycol) oligomer fractions were used, when adulterated with alkali- metal salts, as internal exact mass reference compounds in fast atom bombardment mass spectrometry for the mass range of 700-2100 daltons. Abundant [M + metal] + ions are produced with dithiothreitol/ dithioerythritol and m-nitrobenzyl alcohol matrices for the monosubstituted poly(ethylene glycol) and poly(propylene glycol) surfactants, respectively. The uses of these internal mass standards for the determination of the exact masses of a number of pharmaceuticals in the manual and computerized peak matching modes are illustrated. - Anal. Chem. 62, 322--327 (1990). Am. Cyanamid Co., Med. Res. Div., Lederle Labs., Pearl River, NY (USA)

Elimination of z-ejection in Fourier transform ion cyclotron resonance mass spectrometry by radio frequency electric field shimming. M. Wang and A.G. Marshall.

In Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometry, coherent ion cyclotron orbital motion is produced by resonant radio frequency (rf) electric field excitation. However, because the excitation electrodes are of finite dimensions, the desired transverse (to the applied magnetic field) rf electric field is accompanied by an rf electric field component along the z- (magnetic field) direction, resulting in mass- dependent z-ejection and mass-dependent FT/ICR mass spectral peak relative magnitudes. Addition of several "guard wires" of voltage-div- ided rf amplitude allows the rf electric field to be "shimmed" to near- perfect uniformity. In this paper (see also the accompanying paper by Russell et al.), we introduce two types of rf-shimmed ion traps. In the first type, guard wires are placed only in front of the trapping electrodes. In the second type, guard wire rings are placed inside the detector and trapping electrodes. In side-by-side tests of conventional and if-shimmed traps mounted colli-nearly along the z-axis, the ICR signal strength was reduced to ~ 87% and ~ 25% of its unshimmed level by the addition to guard wires or guard rings, respectively. - Anal. Chem. 62, 515-520 (i990). Dept. Chem., Ohio State Univ., Columbus, OH (USA)

Field-corrected ion cell for ion cyclotron resonance. C.D. Hanson, M.E. Castro, E.L. Kerley and D.H. Russell.

The basis for mass analysis by Fourier transform ion cyclotron resonance (FT-ICR) is the motion of ions in a homogeneous magnetic field. Electric fields are used in FT-ICR to modify ion motion (i.e., trapping and excitation fields). Ion interaction with inhomogeneous radio frequency and direct current (dc) electric fields complicates the ion motion and leads to loss of both resolution and sensitivity. Modifying the ge- ometry of the FT-ICR cell to produce uniform ion acceleration and homogeneous dc trapping field results in simplified frequency measurements and studies of ion-molecule reactions. - Anal. Chem. 62, 520- 526 (1990). Dept. Chem., Texas A&M Univ., College Station, TX (USA)

Monoxide ion signals in inductively coupled plasma mass spectrometry. M. Kubota, N. Fudagawa and A. Kawase.

The ion signals of oxide-forming elements (M +) and their monoxides (MO ÷) have been investigated as functions of inductively coupled plasma operating parameters. An appropriate selection of the radio frequency power, carrier-gas flow rate and sampling depth was essential in order to minimize the signal ratio, SMO(+)/SMC+). Signals SMo<+~ and SM(+) decreased drastically with increasing radial distance from the plasma center. The signal ratios S~o~÷)/SM<+I for various analytes, in consideration of partition functions and mass numbers, showed a linear relation with the oxide dissociation energies. Equivalent concentration data are also given for typical oxide interferences. - Anal. Sci. 5, 701 - 706 (1989). Nat. Chem. Lab. Ind., Higashi, Tsukuba, Ibaraki (J)


Characterization and optimization of HPLC for on-line preconcentration of trace metals with detection by ICP-mass spectrometry. D.W. Boomer, M.J. Powell and J. Hipfner.

Ausgangspunkt der vorliegenden Arbeit war die Priifung einer kommerziellen Kationen-Austauschersfiule (Dionex Ionpac cation guard Cartridge HPIC-CS5) zur Spurenanreicherung von Metallionen. Zus/itzlich wurden die Vorteile des Anschlusses dieser S~iule an einen hochemp- findlichen elementselektiven Detektor fiberpr0ft. Zum Beschicken und Transport der mobilen Phase wurde ein Hochleistungs-Ionenchromato- graph (HPIC) mit Hochdruckpumpe und Ventilsystem eingesetzt, zur Detektion ein ICP-Massenspektrometer, als Interface diente ein Flfissig- keitstransportr6hrchen mit engem Innenquerschnitt. Optimiert wurde die HPIC/ICP-MS-Kombination durch Variieren von Konzentration und Fliel3geschwindigkeit zweier Eluenten (Salpeter- und Salzs/iure). Ebenfalls variiert wurde der pH der Probe, und es wurde die Sfiulenkapa- zitfit mittels Durchbruchtests bestimmt. Ergebnisse der Prfifung des Ge- samtsystems mit den Elementen Cu, Cd, Hg und Pb werden vorgestellt und interpretiert. - Talanta 37, 127-134 (1990). Ontario Ministry Environment, Inorg. Trace Contain. Sect., Rexdale, Ont. (CDN)

W. Czysz

Flow injection analysis - inductively coupled plasma]mass spectrometry: study of interelement effects. H.M. A1-Swaidan, N. Lacy and G.D. Christian.

Verff. beschreiben ein Fliel3injektionsanalyse-ICP-massenspektrome- trisches System (FIA/ICP-MS), bei dem ein Sciex Elan-Ger~it, Modell 250 (ICP-MS) mit einer Peristaltikpumpe und einem Injektionsventil gekoppelt ist. Es werden Probenaliquots von 25 gl injiziert und im Abstand yon 1 min je Injektion gemessen. Die Versuche zeigen, dab durch Zugabe von Salpeters/iure zur Trfigerl6sung die aufgezeichneten Signale sowohl verstfirkt als auch stabilisiert werden. Zus~itzlich bewirkt die Salpetersfiure eine Reduzierung yon Interelementst6rungen. Die mei- sten Interelementeffekte bleiben oberhalb 0,1 ppm je zugegebenem Ele- ment konstant. Untersuchte Elementpaare sind Cd/Ag, Cu/Co, Ni/Cr, Ag/Cd, Mn/Cr und Cr/Ni. - Anal. Lett. 22, 2653-2663 (1989). Dept. Chem., Fac. Sci., King Saud Univ., Riyadh (Saudiarabien); Dept. Chem., State Univ., Seattle, WA (USA) W. Czysz

Minimization of interferences in inductively coupled plasma mass spectrometry using on-line preconcentration. E.M. Heithmar, T.A. Hinners, J.T. Rowan and J.M. Riviello.

A semiautomated system is used to preconcentrate Ti, V, Mn, Ee, Co, Ni, Cu, Cd, and Pb, in order to remove high salt matrices. The preconcentration system accepts digests with acid concentrations equivalent to 0.8 -- 1.4% HNO3, neutralizes them, and loads them onto a macroporous iminodiacetate resin. The alkali and alkaline-earth metals, along with deleterious anions such as chloride, are washed off the resin before and analyte metals are eluted with nitric acid. A total of 13 isotopes of the analytes are measured. An examination of the apparent concentration efficiencies, as well as the behavior of two internal standard elements added to the eluate stream, indicates that the elution front matrix enhances ICP-MS response of the analytes. Investigation of the nature of the blank signals suggests that the detection limits of several of the isotopes could benefit by much larger preconcentration factors, while those of vanadium, copper, cadmium, and lead are currently limited by reagent purity and laboratory contamination. The preconcentration system is evaluated on several simple synthetic matrices, as well as on synthetic seawater and three wastewaters. Digestion of samples containing natural organic chelators is required. -- Anal. Chem. 62, 857-864 (1990). U.S. Environ. Protect. Agency, Las Vegas, NE (USA)

Laser desorption electron impact: Application to a study of the mechanism of conjugation of glutathione and cyclophosphamide. Z.-M. Yuan, C. Fenselau, D.M. Dulik, W. Martin, W.B. Emary, R.B. Brundrett, O.M. Colvin and R.J. Cotter.

Toward the objective of producing ion radical species from involatile and thermally labile samples, we have combined laser desorption of neutral molecules with electron impact ionization on a time-of-flight mass analyzer with a delayed draw-out pulse. The analytical capabilities of this method are tested in the analysis of isotope labels in the involatile product in a mechanistic study of both the chemical and the enzyme

catalyzed reactions of cyclophosphamide with glutathione. - Anal. Chem. 62, 868-870 (1990). Dept. Chem. Biochem., Univ. Maryland Baltimore County, Baltimore, MD (USA)

Scientometric study of the state of the art and trends in chromatographic methods and instrumentation (Review). Yu.I. Yashin.

Die vorgelegte Ubersicht behandelt den heutigen Zustand und die Entwicklungsperspektiven yon chromatographischen Methoden (CM) und ihrer Ger/iteausriistung. CM haben heutzutage unter den analytischen Methoden eine fiihrende Stellung, wovon auch die Tatsache zeugt, dab jede dritte in der Welt und jede vierte in der SU ver6ffentlichte analytische Methode CM betreffen. Dasselbe gilt ffir die Ger/iteproduk- tion, yon der 70% ffir CM bestimmt sin& Die Llbersicht gibt den Anteil yon CM betreffenden Ver6ffentlichungen an der Gesamtzahl analyti- scher Publikationen in den Jahren 1977-1988 an, sowie die Zahl der Publikationen, die einzelnen CM, besonders der Gas- und Flfissigkeits- Cbromatographie, Elektrophorese und anderen CM sowie verschiedenen Varianten der Gas-Chromatographie gewidmet sind. Zum Schlug diskutiert man die Problematik des Einsatzes der Gas-, Flfissigkeits- und Ionen-Chromatographie in der analytischen Chemic; es folgt daraus, dab CM in den wichtigsten Gebieten yon Industrie, Wissenschaft und Technik breit genutzt werden. - Zh. Anal. Khim. 44, 1941 - 1950 (1989) (Russisch, mit engl. Zus.fass.). Forsch.ind. Verband ,,Khimavtomatika", Dzerzhinsk (SU) F. Jancik

Information theory of optimization in chromatography. Y. Hayashi. A theory on flow rate optimization in column chromatography is

presented on the basis of information theory. The quality of a given chromatogram is evaluated by the information flow 5 which is defined as the time-averaged amount of Shannon mutual information called FUMI. The theory developed here is a universal one: the new formula of FUMI, put-forward here, takes a general form applicable to system evaluation, design and optimization of any chromatographic variables which can be related to Gaussian peak shape. - Anal. Sci. 6, 15 -19 (1990). Sect. Instr. Anal., Nat. Inst. Hyg. Sci., Setagaya, Tokyo (J)

Theoretical study of system peaks in linear chromatography. S. Golshan- Shirazi and G. Guiochon.

A complete theory of system peaks in linear chromatography is presented. This theory relates the position and importance of the peaks of sample components and additives observed to the competitive isotherms of the compounds involved. In the case when the additive gives a detector response while the sample components do not, the theory permits the prediction of the response factors. The theory permits the simulation of the method of elution on a plateau for the determination of competitive isotherms. - Anal. Chem. 62, 923-932 (1990). Dept. Chem., Univ., Knoxville, TN (USA)

Normalized measure of overlap between non-Gaussian chromatographic peaks. E.V. Dose and G. Guiochon.

A measure of overlap f~ between two chromatographic peak shapes is defined for the general case. Properties ofinvariance to chromatographic time and concentration scales, commutativity with respect to peak ident- ity, and scaling of Q to the range [0,1] are demonstrated. Analytical expressions for fl between Gaussian, Lorentzian, rectangular , right- triangular, and isosceles-triangular peak shapes are derived and discussed. The measure f~ appears to be a natural measure of the power of a preparative-chromatographic method to enrich two components of a solution much as the resolution R~ measures the power of an analytical method to resolve two peak shapes for analyte quantitation. -- Anal. Chem. 62, 174-181 (1990). Dept. Chem., Univ., Knoxville, TN (USA)

Characterization of overlapped chromatographic peaks by their second derivative. The limit of the method. E. Grushka and D. Israeli.

The second derivative of a chromatographic signal can aid in the recognition of composite peaks. In the case of a two-component composite, the second derivative has three maxima and two minima. The time position of the second of the three maxima is indicative of the point where the peak envelope of each component cross each other. This second maximum can be used to trigger the end of integration of the first component and the beginning of the integration of the second


component. In theory, the second derivative approach works well. The present paper investigates the limits of the method. It was found that, depending on the separation between the two components in the composite, there is a peak height ratio below which the method fails to recognize the existence of a composite system. The greater the separation, the smaller the height ratio. At 4c~ separation, the minimum height ratio that the method can still recognize as a composite is around 10 -s. However, the useful range of the approach may extend to a lower range of height ratios due to the small changes in the area with relatively large changes in the peak height ratio. Noise also affects the useful range of the method. In general, as the nois e increases, the method fails at higher peak height ratios. A surface describing the useful range of the method is given as a function of the signal-to-noise ratio, the separation, and the height ratio. - Anal. Chem. 62, 717-721 (1990). Dept. Inorg. Anal. Chem., The Hebrew Univ., Jerusalem (IL)

Accuracy of peak deconvolution algorithms within chromatographic inte- grators. A.N. Papas and T.P. Tougas.

The soundness of present-day algorithms to deconvolve overlapping skewed peaks was investigated. From simulated studies based on the exponentially modified Gaussian model (EMG), chromatographic peak area inaccuracies for unresolved peaks are presented for the two deconvolution methods, the tangent skim and the perpendicular drop method. These inherent inaccuracies, in many cases exceeding 50%, are much greater than those calculated from ideal Gaussian profiles. Multiple linear regression (MLR) was used to build models that predict the relative error for either peak deconvolution method. MLR also provided a means for determining influential independent variables, defining the required chromatographic relationships needed for prediction. Once forecasted errors for both methods are calculated, selection of either peak deconvolution method can be made by minimum errors. These selection boundaries are contrasted to method selection criteria of present data systems' algorithms. - Anal. Chem. 62, 234 - 239 (1990). U.S. Food Drug Admin., Winchester Engin. Anal. Cent., Winchester, MA (USA)

Calibrating detector responses using chromatographic peak shapes. E.V. Dose and G. Guiochon.

A new method for calibrating time-independent detector responses using only a series of chromatographic peak shapes is presented. The method provides an alternative to steady-state detector calibration which may be difficult experimentally, as in gas chromatography, or too expensive or material-intensive, as in preparative chromatography. In the new method a calibration-curve model function is adopted, and model parameter values are determined. The values used are those that minimize the difference between the analyte amounts injected into the chromatography and the analyte amounts computed from applying the calibration curve to the experimental peak shapes. Examples of applications to linear and nonlinear calibration curves are given. Anal. Chem. 62, 816-820 (•990). Dept. Chem., Univ., Knoxville, TN (USA)

Computer-assisted optimization of selectivity (mobile phase, pH, and ion concentration) in high-performance liquid chromatography. Q.-S. Wang, R.-Y. Gao and H.-Y. Wang.

A computer-assisted method is presented for optimization of mobile phase composition in reverse-phase and normal-phase HPLC. The method is based on window diagrams, but only three preliminary tests are required. The method is successfully applied to two examples and there is good agreement between predicted and experimental results. Optimal values for ion concentration and pH in ion chromatography from a published optimization method are compared to values calculated using the computer-assisted method presented in this paper. The same results are obtained, but the method presented here is simpler and faster than the previously published one. - J. High Resolut. Chromatogr. 13, 173 - 177 (1990). Nat. Lab. Element.-Org. Chem., Nankai Univ., Tianjin (RC)

The application of porous graphitic carbon as an HPLC stationary phase. B.J. Bassler and R.A. Hartwick.

PorSser Graphitkohlenstoff kann als stationS.re Phase in der HPLC Anwendung finden. Die Retention hfingt dabei von der Elektronen-

dichte, vonde r Anzahl und Lokalisation der ~-Bindungen und ihrer Ffihigkeit, entsprechende Wechselwirkung mit der Graphitoberflfiche einzugehen, ab. Daher eignet sich diese Methode zur Trennung von Positions- und Stereoisomeren, was an Beispielen (Phenol-Isomere, Ste- roide, Antibiotica) gezeigt werden kann. - J. Chromatogr. Sci. 27, 162 - 165 (1989). Dept. Chem., Rutgers Univ., Piscataway, NJ (USA)

M. Rittich

Characterization of C18 chemically modified silica-gel and porous glass phases by high resolution solid state NMR spectroscopy and other physicochemical methods. B. Buszewski.

Two types of packing materials, porous glass (PG) and silica gel (SG) have been modified by mono- and difunctional octadecylchlorosflane. The packing surfaces before and after chemical modification have been characterized by CP/MAS NMR, SIMS, porosimetrical, elemental and chromatographic methods. On the basis of the physico-chemical and chromatographic data the PG and SG (of similar porosity) used as supports of chemically bonded phases for RP HPLC, have been compared. - Chromatographia 29, 233-242 (1990). Inst. Org. Chem., Univ., Tfibingen (D)

Effects of steric protection on the preparation of silica based strong cation ion-exchange packings. D.J. Gisch and D.A. Nelson.

Starke Kationen-Ionenaustausch-Sfiulenmaterialien werden durch Sulfonierung verschiedener aromatisch gebundener Phasenoberflfichen hergestellt. Dabei kommt es normalerweise teilweise auch zu einer Spaltung der aromatischen Phase. Durch den Anbau einer tert-Butyl- gruppe an die Silylgruppe erfolgt eine Stabilisierung der aromatischen Phase. Der Mechanismus dieser Stabilisierung ist nicht bekannt. - J. High Resolut. Chromatogr. 1, 478-480 (1989). Supelco Park, Bellefonte, PA 16827 (USA) M. Rittich

Molecular posture of solute adsorbed to stationary alkyl ligand in reversed- phase liquid chromatography. A. Kaibara, T. Nakagawa, C. Hohda, N. Hirata and H. Tanaka.

Molecular posture of a solute adsorbed to the stationary alkyl ligand in reversed-phase liquid chromatography (RPLC) is discussed in terms of the number of displacing solvent molecules (r value) defined in accord with the displacement model concept. The precise investigation of the rc values (r value relati'ge to that of benzene) for various solutes having different polarities of substituent groups suggests that the molecular posture depends on the hydrophilicity of substituent groups, which affects the hydrophobic surface area of solute kept in contact with the alkyl chain of the stationary ligand. - J. Chromatogr. Sci. 27, 716 - 720 (1989). Fac. Pharm. Sci., Univ., Sakyo-ku, Kyoto (J)

Chromatographic characterization of silica C18 packing materials. Corre- lation between a preparation method and retention behavior of stationary phase. K. Kimata, K. Iwaguchi, S. Onishi, K. Jinno, R. Eksteen, K. Hosoya, M. Araki and N. Tanaka.

A variety of octadecylsilylated silica gel phases are prepared under various conditions, and their chromatographic properties are studied in order to carry out chromatographic characterization of commercial C 1 s packing materials. The test scheme, utilizing several sets of solutes, provides information about hydrophobicity, steric selectivity, and the extent of hydrogen bonding and electrostatic interactions. The results permit the estimation of how the commercial packing materials were prepared. - J. Chromatogr. Sci. 27, 721-728 (1989). Kyoto Inst. Tech- nol., Dept. Polym. Sci. Engin., Matsugasaki, Kyoto (J)

CP-MAS13C nuclear magnetic resonance spectra for identification of functionality of octadecylsilica bonded phases. K. Jinno.

Cross-polarization (CP) and magic angle spinning (MAS) carbon-13 solid state nuclear magnetic resonance spectrometry (NMR) is used to identify the functionality of octadecylsilica stationary phases. The NMR method is compared to the retention behavior method for the identification. The NMR spectra indicate various features, depending on the functionality of the bonded phases. - J. Chromatogr. Sci. 27, 729-734 (1989). Sch. Mater. Sci., Univ. Technol.; Toyohashi (J)

Comparison of the adsorption isotherms for monomeric and polymeric C 18 bonded phases. K. Tani and Y. Suzuki.


The adsorption isotherms of polymeric Ca8 bonded phase were compared to those of monomeric C18 bonded phase in three mobile phase systems. The results indicate that the bonded phases in methanol/ dichloromethane are more rigid than those in aqueous organic mixtures, and the polymeric Ca s bonded phase is more tight than the monomeric Ca8 bonded phase. - J. Chromatogr. Sci. 27, 698-703 (1989). Fac. Engin., Yamanashi Univ., Takeda, Kofu (J)

Comparison of thermodynamic retention behaviors on various C1 s columns different in their hydrophobicity. F.M. Yamamoto, S. Rokushika and H. Hatano.

To characterize the packing materials, an apparent solubility parameter of the stationary phase, 5 ' , is introduced from a solubility concept model. The 5's values for ten different commercially available octadecyl silica materials are determined with a 30% aqueous methanol eluent and toluene as a test solute. The calculated values range from 18.73 to 19.03 (cal/cm3) a/2, values greater than the value of 5 for alkane but smaller than the value for the solvating layer on the hydro- carbonaceous chains. Silanization of the remaining silanol groups on a silica surface results in the increase of the 5's value. A thermodynamic retention behavior of purine bases on various C18 bonded columns is explained on a basis of the 5's value. An enthalpy-entropy compensation relationship is obtained for the retention of a purine base on the Ca8 columns examined here. - J. Chromatogr. Sci. 27, 704-709 (1989). Dept. Chem., Fac. Sci., Univ., Kyoto (J)

Eluentenentgasung mit gasselektiven Membranen. W. Stubba. Das beschriebene Entgasungssystem kann die bisher angewandten

Methoden zur Entgasung yon Eluenten in der HPLC ersetzen. Die entwickelte Kunststoffmembran ist gasdurchlfissig aber flfissigkeitsun- durchl~issig. In einer mittels einer Vakuummembranpumpe evakuierten Vakuumkammer befindet sich ein solcher Membranschlauch. Die Druckdifferenz zwischen Innen- und AnBenseite der Membran bewirkt ein kontinuierliches Entziehen der im durchstr6menden Eluenten gel6- sten Gase. - Labor-Praxis 13, 758-762 (1989). ERC, Ges. ffir Vertrieb wiss. Gedite mbH, Alteglofsheim b. Regensburg (D) M. Rittich

A simple procedure of calculating the capacity ratio in liquid adsorption chromatography with ternary mobile phase. M. Bor6wko and B. O~cik- Mendyk.

New dependences of the capacity ratio on composition of ternary mobile phase are proposed and tested on experimental data. The first type of relationships are derived for constant ratio of mole fractions of two solvents in the mobile phase, whereas the second type of equations describe the chromatographic process when the mole fraction of any solvent in the mixed eluent is fixed. - J. Liquid Chromatogr. 12, 2601 - 2610 (1989). Dept. Chem., Univ., Lublin (PL)

Calculation of solute retention for pH gradient elution HPLC experiments using single and coupled columns. C.F. Buck and S.A. Tomellini.

Die Berechnung von Retentionszeiten fiir die nicht-lineare pH-Gra- dientenelution bei der HPLC gelingt mit einer Abweichung von maximal 5%. Dies gilt sowohl ffir einzelne als auch ffir Doppelsfiulen. Die berech- neten Ergebnisse stimmen gut mit den experimentellen iiberein. - J. Chromatogr. Sci. 27, 166-171 (1989). Dept. Chem., Univ., Durham, NH (USA) M. Rittich

Novel prediction of solute retention in NP-HPLC with the alcohobaliphatic hydrocarbon mobile phases. T. Kowalska.

Die vom Autor entwickelte Methode zur Quantifizierung des Einflus- ses intermolekularer Wechselwirkung zwischen den Komponenten ge- mischter mobiler Phasen ist, wie vorher gezeigt, nicht nut ffir die TLC anwendbar, sondern auch in der NP-HPLC. -- J. High Resolut. Chroma- togr. 12, 474-476 (1989). Inst. Chem., Silesian Univ., Katowice (PL)

M. Rittich

Suspension postcolumn reaction detection method for liquid chromatography. D.T. Gjerde and J.V. Benson.

A novel detection method for HPLC utilizes the addition of a colloidal suspension of solid reagent postcolumn to the eluant stream. The average particle size of the insoluble solid reagent is small enough to keep it in

suspension. The solid reagent may react with the sample to reduce the background signal or may react with the eluate making it detectable. Since the reagent is solid, it is "invisible" to detectors that repond only to the liquid phase, e.g. conductometric and potentiometric detectors. This paper examines the properties of sulfonated polystyrene-type solid reagents and describes their application in conductivity detection. Other potential uses of the solid phase reagents are discussed. - Anal. Chem. 62, 612-615 (1990). Sarasep, Inc., Santa Clara, CA (USA)

Single optical fiber, position-sensitive detector-based multiwavelength absorbance spectrophotometer. C.N. Renn and R.E. Synovec.

A relatively simple, yet stable and versatile, multiwavelength absorbance spectrophotometer is described. A broad-band mercury-xenon source was coupled into a single UV-vis transmitting optical fiber, through a detection cell, and dispersed by a monochromator onto the face of a continuous position-sensitive detector (PSD). Two wavelength regions illuminated opposite ends of the PSD while the remainder of the dispersed light was masked. Photocurrent contributions by the two wavelength regions were readily balanced to achieve a stable electronic null condition. The resulting optical configuration provided absorbance measurements simultaneously at two wavelengths, while also correcting for light source intensity fluctuations and refractive index aberrations. The absorbance detector was applied in microbore LC with a 6 mm path length z-configuration flow cell (1.2 pl volume). A 1.1 x 10 - 4 a n (3 X root mean square noise level, 60-s intervals) was routinely achieved, which constitutes over a factor of 10 reduction in noise due to light source fluctuations. Aldehyde derivatives with 2,4-dinitrophenylhydrazine were chromatographically analyzed as a test system. The mass detection limit of injected formaldehyde was 4 pg. Since two wavelength regions are simultaneously measured, molar absorptivity ratios of the aldehyde derivatives were obtained and compared to absorbance spectra obtained from a commercial instrument. - Anal. Chem. 62, 558-564 (1990). Center Process Anal. Chem., Dept. Chem., Univ., Seattle, WA (USA)

Elektrochemische Detektion in der HPLC. Ausgew/ihlte Beispiele aus biochemisch- und umweltrelevanten Fragestellungen. N. Wenkel.

Mittels HPLC und elektrochemischer Detektion wird die Auftrennung von Aminos/iuregemischen unter Verwendung von F~ingerreagentien durchgefiihrt. Nach Austausch der Elektrode kann mit der gleichen Methode Ethylenharnstoff in Fungiciden bestimmt werden. - Labor- Praxis 14(I/2), 46--50 (1990). Axel Semrau GmbH, Sprockh6vel (D)

H. Hoffmann

Surface-enhanced Raman spectroscopy at a silver electrode as a detection system in flowing streams. N.J. Pothier and R.K. Force.

An analytical application for surface-enhanced Raman spectroscopy at a silver electrode is described. Raman spectra of several DNA bases have been recorded in a 30-gl flow cell under flowing conditions. An optical multichannel analyzer allowed high-quality spectra to be recorded with integration times of less than 5 s. The Raman intensity vs concern tration yields a monotonic relationship over 4 orders of magnitude. Limits of detection fo adenine, thymine, and cytosine were 175, 233, and 211 pmol, respectively. The samples could be rapidly desorbed off the surface of the electrode in less than l0 s. The technique shows promise as a solute property detector for HPLC and flow injection analysis. - Anal. Chem. 62, 678-680 0990). Dept. Chem., Univ., Kingston, RI (USA)

Characteristics of an amperometric detector for capillary HPLC. V.F. Ruban.

The main characteristics of a dual electrode amperometric detector with a cell of the "cylinder-in-flow" type with a working wire electrode have been investigated. The effective cell volume is 10-40 nl in a system with 0.2-0.4 mm i.d. packed fused-silica columns. Extra-column spreading at the optimum elntion rate does not exceed 01005 gi z. The linear range is 103 at a relative standard deviation of 0.009. The low noise level ( 2 - 3 pA) facilitates determination of electro-active substances. The detection limit for catecholamines is of the order of tenths of a femtomole. -- J. High Resolut. Chromatogr. 13, 112-115 (1990). Inst. Macromol. Comp. Acad. Sci., Leningrad (SU)


Adaptation of a thermospray liquid chromatography/mass spectrometry interface for use with alkaline anion exchange liquid chromatography of carbohydrates. R.C. Simpson, C.C. Fenselau, M.R. Hardy, R.R. Townsend, Y.C. Lee and R.J. Cotter.

An interface is described that allows the direct coupling of high- performance alkaline anion exchange liquid chromatography with thermospray mass spectrometry. A membrane suppressor is used to remove nonvolatile alkaline salts from the mobile phase after the chromatographic process is completed and prior to introduction into the mass spectrometer. Examples are given of both isocratic and gradient separations of a three-component test mixture of N-acetylated mono- and disaccharides, followed by on-line mass spectral data acquisition. Sensitivity studies show minimum detection limits for the test compounds to be in the microgram range, - Anal. Chem. 62, 248-252 (1990). Dept. Chem. Biochem., Univ., Baltimore, MD (USA)

Effective on-line coupling of HPLC and flame-AAS by means of hydraulic high pressure nebulization. G. Weber and H. Berndt.

Hydraulic high pressure nebulization is used as an effective way of on-line coupling of HPLC to flame-AAS for speciation of metal compounds in the ng range. Compared to coupling with a conventional nebulizer a signal enhancement by a factor of 7.5 (peak height) and 10.1 (peak area) for copper is obtained. Using an injected volume of 50 ~1 the detection limits for Cu, Fe, Ni and Cd are below 0.1 gg/ml (= 5 ng) and for Mg below 0.01 gg/ml (= 0.5 rig). The effects of HPLC flow-rate and nebulization nozzle diameter on the signal peak height have been investigated. The performance of the system is demonstrated using speciation of iron. A base-line separation of Fe(II) and Fe(III) is achieved within two minutes. Also species changes (Fe acetate to Fe citrate) carl be analysed using the proposed system. - Chromatographia 29, 2 5 4 - 258 (1990). Inst. Spektrochem. angew. Spektrosk., Dortmund (D)

Phenylalanine as eluent for indirect photometric detection. K.Y. Jiang, M.C. Liu, Z.D. Hu and P.L. Zhu.

In this paper the use of phenylalanine as eluent for indirect photometric chromatography is reported. The effects of the mobile phase pH, phenylalanine concentration etc. on the eluent strength and the sensitivity of detection are discussed. Using 3 mM aqueous solution of phenylalanine at pH 3.0 containing 1% methanol as the mobile phase, a mixture of alkali metals was separated and sodium ion concentration in water was determined on a low-capacity cation-exchange column. - Chromatographia 29, 131-134 (1990). Dept. Chem., Univ., Lanzhou ( a c )

Thermospray enhanced inductively coupled plasma atomic emission spectroscopy detection for liquid chromatography. S.B. Roychowdhury and J.A. Koropchak.

Thermospray sample introduction is studied as an interface between LC and ICP-AES for metal speciation studies. Detection limits for chromium species separated by ion chromatography or mobile phase ion- pairing chromatography are improved by factors of 24 and 36, respectively, for 50 and 25 ~tm aperture based thermospray system, as compared to pneumatic sample introduction. For arsenic species separated by ion chromatography, relative response factors between the two sample introduction systems were species dependent. Lower enhancements for certain species with thermospray were thought to result from thermal decomposition to form volatile species which were lost during desolva- tion. For nonaqueous size exclusion studies of organoiron species, detection limits were improved by a factor of about 50 with thermospray compared to a pneumatic sample introduction system. - Anal. Chem, 62, 484-489 (1990). Dept. Chem. Biochem., Univ., Carbondale, IL (USA)

Liquid adsorption chromatography of metal chelates. Connection of chromatographic parameters and extraction distribution constants. A~R. Timerbaev, I.G. Tsoy and O.M. Petrukhin.

Man untersuchte das Verhalten der Chelate von Mn, Co, Ni, Pb, Cu, Bi, Zn, Cd un d Hg mit Diethyldithiocarbamat bzw. Diethyldithiophos- phat bei ihrer HPLC-Analyse mit Normal-(NP-HPLC) bzw: Umkehr- phasen (RP-HPLC). Gleichzeitig wurden die Verteilungskoeffizienten (D) dieser Chelate bei der Extraktion aus w/iBrigen L6sungen mit organi-

schen L6sungsmitteln (Benzol, Toluol, Octanol) bestimmt. Die Abh~ingigkeit der log k'-Werte (k' = Kapazit/itsfaktor) dieser Chelate bei NP- HPLC bzw. RP-HPLC von ihren log D-Werten in der Extraktion mit den erw/ihnten L6sungsmitteln verl/iuft linear, so dab diese Abhfingigkeit zur Vorhersage der Retentionsparameter der erw/ihnten Chelate bei NP- HPLC bzw. RP-HPLC mit Acetonitril/Wasser bzw. Dioxan/Wasser als mobilen Phasen verwendet werden kann. - Zh. Anal. Khim. 44, 1847 - 1853 (1989) (Russisch, mit engl. Zus.fass.). Mendeleev Chem. technol. Inst., Moskau (SU) F. Jancik

Simulated counter-current moving column chromatography used in the continuous separation of carbohydrate mixtures. P.E. Barker, A. Knoechelmann and G. Ganetsos.

A moving column-bundle counter-current chromatographic system consisting of twelve 0.9 cm id x 72.5 cm long glass columns has been used for the separation of glucose-starch and glucose-maltose mixtures. The system was packed with Spherosil XOBO75 for the glucose-starch separation and with Dowex-5OW-X4K + for the glucose-maltose separation. Purities of up to 100% were obtained and the operating throughputs were up to 4.4 kg sugar solids/m 3 resin/h. - Chromatogra- phia 29, 161-166 (1990). Dept. Chem. Engin. Appl. Chem., Aston Univ., Birmingham (GB)

Selectivity related to carbon loading and endcapping of octadecyl bonded silica gels in the reversed-phase liquid chromatography of phenolic compounds. J. Yamaguchi and T. Hanai.

Four types of octadecyl bonded silica gels, high carbon loaded and low carbon loaded, with and without endcapping, were synthesized. The retention times of phenolic compounds were measured for these ODS packings in acidic aqueous acetonitrile solutions. Their selectivity indices and enthalpies were measured and compared with those of alkylbenzenes and chlorobenzenes. The retention mechanism of nonionizable compounds was similar for these packings, while that of phenolic compounds appeared quite different in consideration of their selectivity indices and enthalpies. The humidity of ODS packings may possibly be a determining factor in the retention of polar compounds. - J. Chromatogr. Sci. 27, 710-715 (1989). Res. Inst., Gasukuro Kogyo Inc., Iruma (J)

Radiometric and fluorimetric determination of aminosilanes and protein covalently bound to thermally pretreated glass substrates. L. Locascio- Brown, A.L. Plant, R.A. Durst and M.V. Brizgys.

Verff. beschreiben ein Verfahren zur Derivatisierung von Natronglas- kfigelchen mit Aminosilanen. Sie bestimmen die Stabilitfit dieser Grup- pen in der N/ihe des physiologischen pH in flieBenden w/il3rigen Pufferl6- sungen. Dann bestimmen sie die Anwesenheit und die Menge der immo- Nlisierten und adsorbierten AminosiIane an den Glasoberfl/ichen, zum einen radiometrisch, zum zweiten fluorimetrisch. Das letztere Verfahren ist weniger aufwendig und auch aus gesundheitlichen Grfinden ffir den Analytiker vorzuziehen. Kurzzeitiges Erhitzen der Glaskfigelchen auf 200°C vor der Derivatisierung erleichtert diesen ProzeB (Vertreiben von adsorbiertem Wa~ser). Die Vorbehandlung sollte aber auf max. 1 - 2 h beschr/inkt werden, da bei lfingerem Erhitzen der Derivatisierungsgrad exponentiell abnimmt. Die Bestimmung von nanomolaren Konzentra- tionen der Aminosilane unter Verwendung von Fluorescamin wird beschrieben. Ebenso ein Verfahren zur kovalenten Anbindung yon Rinder- serumalbumin an die vorbehandelten Glasperlen. - Anal. Chim. Acta 228, 107-116 (1990). Center Anal. Chem., Nat. Inst. Standards/Tech- nol., Gaithersburg, MD (USA) W. Czysz

Synthesis and chromatographic properties of an HPLC chiral stationary phase based upon human serum albumin. E. Domenici, C. Bertucci, P. Salvadori, G. F61ix, I. Cahagne, S. Motellier and I.W. Wainer.

A new HPLC stationary phase was synthesized by the in situ covalent immobilization of human serum albumin (HSA). The protein was immobilized on a commercially available diol column which had been activated with 1,1-carbonzcldiimidazole. Initial chromatographic studies show that this phase can be used for chiral separations of enantiomeric solutes and that these separations may reflect in vitro binding to the HSA. The effects of mobile phase composition and temperature on the stereochemical resolutions are reported. - Chromatographia 29, 170 176 (1990). St. Jude Child. Res. Hosp., Memphis, TN (USA)


Direct liquid chromatographic separation of enantiomers on immobilized protein stationary phases. VIII. A comparison of a series of sorbent based on bovine serum albumin and its fragments. S. Andersson, S. Allenmark, P. Erlandsson and S. Nilsson.

A mixture of three peptides (Ms 38 000), obtained by enzymatic cleav- age of bovine serum albumin (BSA) was isolated, immobilized to silica and used as a chiral stationary phase in LC. A comparison of sorbents containing these fragments and intact BSA, showed that the enantioselectivity is preserved for only a limited n.umber of compounds. Under identical mobile phase conditions, retention on the columns based on BSA fragments was also much lower than on those containing intact BSA. The method used for immobilization has a great influence on the retentive and enantioselective properties of the sorbent obtained. When sorbents based on BSA entrapped in silica and 3-aminopropylsilica, by cross-linking with glutaraldehyde were compared under identical mobile phase conditions, the latter were generally found to give larger capacity factors and often also larger ~ values. These results indicate that the increased hydrophobicity, primarily caused by the aminopropyl groups, partly contributes to the overall retention and chiral discrimination process and that the situation may be different from that in a solution of the free protein. - J. Chromatogr. 498, 81-91 (1990). IFM/Dept. Chem., Univ., Link6ping (S)

Variation of stationary phases in planar chromatography. T.J. Good and A.G. Taketomo.

Die Trennleistungen abgefinderter stationfirer Phasen mit 3 Entwick- lungsmethoden wurden an einem Farbgemisch und einem aus Spinat- blfittern gewonnenen Gemisch pflanzlicher Pigmente untersucht und verglichen. Fiir die DSC wurden fertige 5 x 10 cm-Kieselgel-Platten (200 gm-Schichtdicke) eingesetzt, unverfindert oder 1 h bei ,100°C aktiviert, sowie nach Modifizieren in eine lineare und eine cyclische Diol-Phase, eine Cyanopropyl- und eine Carboxylsfiureester-Phase, gleichfalls unver- ~indert oder wie oben aktiviert. Alle Versuche liefen bei Ramntemperatur (etwa 25°C). Zur Entwicklung wurden eine normale, senkrechte Trenn- kammer, eine experimentelle, waagerechte Sandwich-Trennkammer und eine experimentelle Hochdruck-Apparatur verwendet. Bei den beiden letzteren konnte fiir die Planar-Chromatographie die Kieselgelschicht beliebig vorkonditioniert werden. Dies wurde im geschlossenen System unmittelbar vor der Entwicklung mit der mobilen Phase angewendet. Die Laufstrecke betrug 7 bzw. 5 cm, die Entwicklungszeit 120 s. Das in Hexan/Ethanol (80:20) gel6ste Farbgemisch enthielt Sudan 3, Sudan Schwarz mit einem gering polaren Nebenprodukt und Alizarin. Etwa 100 ng Probe, mit einer Lambda-Pipette aufgetragen, wurden mit Toluol entwickelt. Der senkrechte Tank wurde etwa 45 min vorges/ittigt, bei den beiden anderen Ger/iten 5 min lang vorbehandelt. Der Pflanzenextrakt enthielt Carotine, Pheophytin, Chlorophyll a und b, Violaxanthin und Neoxanthin. Laufmittel war ein Gemisch aus i-Octan/Methanol/Ethyl- ether (70:10:20), die Laufstrecke 7 cm. Vorbehandelt wurde 5 min. Bei beiden Probegemischen eriibrigte sich eine Nachweisreaktion. Die Rf- Werte der Untersuchungsreihen sind vergleichend in Tabellen wiederge- geben und werden diskutiert. - J. Planar Chromatogr. 2, 10, 383-386 (1989). CERA, Baldwin, Park, CA (USA) A.M. Roscovanu

High resolution functions in analytical and preparative OPLC separations. S. Hara, T. Uchimaru, Y. Hoshi and G. Szepesi.

Overpressured-layer chromatography (OPLC) has a controllable mobile phase flow originating from the closed bed stationary phase and compulsory pumping systems that are not included in ordinary TLC. These features allow increased carrier flow rate and extend the migration distance of the solute on TLC plates. Elution of solutes from a thin layer plate is also possible in OPLC experiments. Consequently, high resolution functions per unit of time should be expected for both analytical and preparative applications. In this paper, closely related terpenoids were selected, and the resolution of sample pairs was examined using conventional TLC and OPLC. OPLC was found to give a high efficiency per unit time. Extraction of a pure specimen separated on a thin layer plate has often been carried out for preparative purposes. Successive elution of sample spots is possible in the operation of OPLC. Thus, the fractionation of pure products from a crude reaction mixture syntheti- cally obtained was examined by OPLC. Closely related diastereometric mixture components were separated and isolated, in a quantity of

milligrams per single TLC plate, within a reasonable period of time. - J. Planar Chromatogr. 2, 430-433 (1989). Tokyo Coll. Pharm., Hachioji, Tokyo (J)

Multidimensional and multimodal thin layer chromatography: Pathway to the future. C.F. Poole, S.K. Poole, W.P.N. Fernando, T.A. Dean, H.D. Ahmed and J.A. Berndt.

Approaches to increasing the separation potential of TLC and to interface TLC to multidimensional detectors yielding structural information for separated zones are made from the perspective of current practices. The separation potential is greatest for two-dimensional forced flow TLC but considerable difficulties remain in quantifying such separations. Unidimensional multiple development may be a more yielding strategy in the near term and is the method of choice for separations achieved with solvent gradients. A lack of a suitable theoretical model for optimizing such separations is a major obstacle to the general use of the technique. Multimodal separations obtained by interfacing column chromatographic techniques and supercritical fluid extraction to TLC are not particularly difficult to implement and are practical solutions to the separation demands of complex mixtures. Mechanical and electronic optical scanning densitometry is likely to remain the principal method of quantitation but there is a strong need for alternative detection techniques yielding structural information for separated samples. At present, low temperature fluorescence methods, surface enhanced Raman scattering, and mass spectrometry are the most viable options to fill this role. - J. Planar Chromatogr. 2, 336-345 (1989). Dept. Chem., Wayne State Univ., Detroit, MI (USA)

Thin-layer chromatography of inorganic ions on polyethyleneimine cellulose in mixed sulfuric acid-organic solvent media. T. Shimizu, H. Hirata and K. Nakajima.

Thin-layer chromatographic behavior of 49 inorganic ions has been systematically studied on polyethyleneimine (PEI) cellulose with solvent mixtures consisting of sulfuric acid and either methanol or acetone. The sorption of most ions on the cellulose increases with increasing methanol content in. the solvent. The feature is noticeable for some ions which form sulfato complexes. The Rf values of Re(VII) slightly increase with increasing methanol content. Ba(II), Hg(II), Pb(II), Pd(II), Au(III), Ru(III), Sb(III), Pt(IV), Mo(VI) and W(VI) are strongly retained on the layer in methanol media. The behavior of most ions in the acetone system does not appreciably differ from that in the methanol system, but their Rf values are somewhat higher in acetone than in methanol. There are marked differences in the behavior of Hg(II), Au(III), Ru(III) and Re(VII) between the two systems. Feasibilities for the separation of many ions of analytical interest are also demonstrated in these systems. - Chromatographia 28, 620-622 (1989). Dept. Chem., Fac. Educat., Gunma Univ., Aramaki, Maebashi (J)

Solid-state dissociation of metal chelates and reagents in a silica gel stationary phase in TLC II. Data on reagents. V.V. Salov, A.R. Timerbaev and O.M. Petrukhin.

The Rf values of reagents containing labile hydrogen are shown to decrease as the reagents' concentrations in the silica gel layer in TLC decrease. These dependences are compared with the similar phenomena for metal chelates. A conclusion drawn is that chelates and reagents dissociate on the silica gel stationary phase. A model accounting for the dissociation of compounds in the stationary phase explains the experimentally observed Rf vs concentration dependences. - J. Planar Chromatogr. 2, 461-463 (1989). Mendeleev Inst. Chem. TechnoI., Moscow (SU)

Solid-state dissociation of metal chelates and reagents in a silica gel stationary phase in TLC. I. Experimental data on chelates. V.V. Salov, A.P. Timerbaev and O.M. Petrukhin.

The Rf value for low-stability metal chelates is shown to decrease with decreasing chelate concentration in a thin silica gel layer in TLC. Two ways of explaining this dependence are discussed: ion exchange of the chelate metal for the hydrogen atom of silanol groups or dissociation of the chelates in the stationary phase. A conclusion drawn is,that for the final choice of the phenomenon's explanation similar data are needed

1.i Fundamentals, methods, apparatus, reagents, automation, data processing 655

for the chelating reagents. - J. Planar Chromatogr. 2, 310-314 (1989). Mendeleev Inst. Chem. Technoi., Moscow (SU)

Investigation of steric effects in molecules of aliphatic alcohols as mobile phases in TLC of ~,~-alkanediols. M. Koralewska and J. Sliwiok.

We investigated steric effects that occur when using aliphatic alcohols as mobile phases in adsorption TLC. It was proved that alcohols with longer aliphatic chains shield their own hydroxyl groups, whereas with C-1 to C-3 alcohols no similar effect takes place. The shielding effect results in increased selectivity of a given liquid-solid chromatographic system when alcohols are used as mobile phases. - J. Planar Chromatogr. 2, 452-455 (I989). Inst. Chem., Silesian Univ., Katowice (PL)

Quantitative evaluation of thin layer chromatograms. 9. Special scanning procedures. M. Prosek, M. PukI, A. Golc-Wondra and D. Fercej- Temeljotov.

The use of a computer controlled scanner and two new scanning procedures are described. The first scanning technique was developed for the evaluation of a plate treated by postchromatographic derivatization. This method is able to construct a reliable baseline and obtain the correct response even when spots are not in a straight line~ It is quicker than other flying spot or peak search techniques. The second scanning procedure was developed for quantitative evaluation of two-dimensional chromatograms. Scanning and integration programs are also described. The evaluation of one selected chromatogram is shown. - J. Planar Chromatogr. 2, 464-468 (1989). KIBK, Ljubljana (YU)

Spectrometric analysis of planar separations using charged-coupled device detection. J.A. Cosgrove and R.B. Bilhorn.

An experimental apparatus using a cooled, slow-scan charged-coupled device (CCD) camera has been evaluated as a detector for the quantitative spectrometric analysis of planar separations. Experimentation has shown this technology capable of providing two-dimensional separation mapping for component detection and XY-coordinate identification, and quantification by either UV/visible absorption of fluorescence. With the introduction of an imaging spectrograph, UV/visible absorption and fluorescence spectra of individual spots can be recorded. In comparison to scanning densitometry, the application of CCD detection technology offers enhanced data acquisition and evaluation capability. Initial feasibility testing has shown imaging densitometry provides as much as an order of magnitude increase in precision, expanded dynamic range, and significantly reduced data acquisition times when compared to the current technology. Initial sensitivity studies have indicated that these two modes of detection are comparable. - J. Planar Chromatogr. 28, 362-367 (1989). Eastman Kodak Co., Anal. Technol. Div., Rochester, NY (USA)

Simultanspektrometer als Detektoren in der Diinnschieht-Chromatogra- phie. S. Bayerbaeh und G. Gauglitz.

Reflexions- und Fluorescenzspektren von Substanzen k6nnen auf Dfinnschichtplatten mit Hilfe von Glasfasern und einem Photodiodenar- ray gemessen werden. Durch die Verwendung der Lichtleiteranordnung und das Simultanspektrometer k6nnen die Dfinnschichtplatten punkt- weise spektraI abgetastet werden. Dadurch kann ffir jede Substanz eine optimale Detektionswellenl/inge ausgew~hlt werden,/iberlappende Zo- hen k6nnen durch Spektrenvergleich erkannt werden, eine Untergrund- korrektur kann durchgeffihrt werden, indem auch bei Wellenl/ingen, bei denen die detektierte Substanz nicht absorbiert, gemessen wird. Das Signal/Untergrund-Verhfiltnis wird durch Integration fiber einen Wellen- 1/ingenbereich verbessert. Der MeBaufbau einer solchen Anordnung und damit erhaltene Ergebnisse werden anhand einiger Beispiele diskutiert. Der Nachteil des Verfahrens liegt beim jetzigen Stand der Technik in der sehr hohen ben6tigten Datenmenge und der notwendigen hohen Lichtintensit~it bei der Detektion, die zur Zersetzung yon photolabilen Substanzen fiihren kann. - GIT Fachz. Lab. 34, 232--234 (1990). Inst. Phys. Theor. Chemic, D-7400 Tiibingen R.H.S.

Planar chromatography coupled with secondary ion mass spectrometry. K.L. Busch.

The use of secondary ion mass spectrometry in the direct analysis of samples separated by TLC is described. Central to the success of the experiment is the correct selection of extraction/sputtering solvent, and the performance of a series of sputtering solvents for the measurement of the mass spectra of some standard compounds is described. The influences of extraction solvent volume and primary ion beam parameters on the time-dependent behavior of the mass spectrum are also followed. Once the correct solvent/sample mix is established, spatially resolved mass spectra can be recorded; examples of the use of TLC/ SIMS in the sputtering of bile acids and diuretics are included. The combination of SIMS with visual analysis of the TLC plate is discussed. Location of sample spots through visual examination leads to much quicker mass spectral analysis, and a reduction in the amount of data processing and storage that must be completed. J. Planar Chromatogr. 2, 355-361 (1989). Sch. Chem. Biochem., Atlanta, GA (USA)

Elution system choice in spectrodensitometric thin layer chromatography. V.I. Kofanov and I.Sh. Kofman.

Two developing directions in instrumental TLC can be reciprocally enriched - optimization of separation applying Soczewinski principles and identification with diffuse reflectance electronic spectra recorded directly from the spots of the separated substances essentially improv- ing a given multicomponent mixture separation. Coefficient values of the equation RM = A - - B ( l o g X ~ ) together with the use of Rf magnitude are proposed for separation characterization. Diphenyl ether derivatives were taken as examples to show the optimization of their effective and selective separation. The coefficients of the Soczewinski equation for binary eluting systems based on hexane with polar additives were determined. The optimum conditions for the substances' chromatographic separation on silica gel TLC plates were found using a simple program for a personal computer. The physical sense of the Soczevinski equation coefficients is discussed and their correlation with chromatographic mobility in pure solvents and with the Snyder polarity criterion (t °) is shown. The averages of the ARf criterion optimization according to chromatographic system efficiency are shown. Chromatographic separation conditions for a microquantity of eight diphenyl ether group herbi- cides on silica gel using two-staged ascending chromatography are given. - J. Planar Chromatogr. 2, 378-381 (1989). Inst. Botany, Ukrainian SSR Acad. Sci., Kiev (SU)

Thin-layer chromatography with supersonic jet fluorometrie detection. T. Imasaka, K. Tanaka and N. Ishibashi.

A mixture sample is developed by a silica gel on a flexible TLC sheet. This is mounted on a sliding sheet roller attached to a supersonic jet nozzle. The first dye laser beam (275 nm) is introduced from a small through-hole to desorb the chemical species on the TLC sheet. The vaporized sample is entrained into a carrier gas of argon, and the gas is then expanded into a vacuum to form a supersonic jet. The sample molecule is detected by fluorescence induced by the second dye laser beam (366-375 rim). This technique allows direct measurements of the excitation spectrum and the chromatogram for the sample developed on the TLC sheet. The amount of sample used for recording a spectrum is 4.4 gg. The detection limits are ~ 10 ng in spectrometric and chromatographic measurements. - Anal Chem. 62, 374-378 (1990). Fac. Engin., Kyushu Univ., Hakozaki, Fukuoka (J)

"Thin-layer chromatography diskette" storage of high-performance liquid chromatographic effluents with off-line laser-induced fluorescence detection. J. Strojek, S.A. Soper, K.L. Ratzlaff and T. Kuwana.

The concept of thin-layer chromatography (TLC) "chemical diskette" is demonstrated whereby high-performance liquid chromatographic (HPLC) effluents are deliverd and stored along a linear path on a TLC surface. The time coordinate normally associated with the HPLC chromatogram is transformed therefore to a spatial coordinate on the solid matrices. After the HPLC analytes have been deposited on the TLC in a pre-determined pattern as controlled by a computer, the pattern can be retraced and interrogated by various spectroscopic methods. In the present demonstration, the analytes are detected by fluorescence where an optical fiber carries the laser beam for excitation. The LC/TLC diskette method was experimentally implemented by replacing the pen of high resolution digital x-y recorder with the outlet tube ofa microbore


HPLC column. The writing rate and pattern of the LC effluent on the TLC plate were controlled by the x -y recorder as driven by a microcomputer. After removal of the LC solvent, the adsorbed analytes on the TLC surface were interrogated by retracing the pattern with the He-Cd laser irradiation as carried by the optical fiber on the pen holder. Other fibers on the same holder collect and transmit the fluorescent emission to the detection system. The detection limits were in the low femtomole range for two amino acids derivatized by naphthalenedi- aldehyde. Also, it was possible to detect di-derivatized lysine, which was not quenched as in the solution phase, on the TLC surface. - Anal. Sci. 6, 121 - 1 2 6 (1990). Center Bioanal. Res., Univ. Kansas, Lawrence, KS (USA)

High-performance thin layer chromatography (HPTLC) - a versatile technique for industrial applications. M.L. Langhorst.

HPTLC can be used for diverse analytical applications. This paper describes a variety of applications of the technique, emphasizing flexi- bility with a simple set of equipment. These applications, in the areas of environmental, agricultural, toxicology, organic, and polymer research, illustrate trace quantitative capabilities, high sample throughputs, simple visualization of compounds which are difficult to detect, the ability to handle relatively "dirty" (complex) samlSle matrices with minimal sample clean-up, and the ability to help solve difficult analytical problems. - J. Planar Chromatogr. 2, 346-354 (1989). Dow Chem. Co., Anal. Sci., Midland, MI (USA)

Automated instrumentation for comprehensive two-dimensional high-performance liquid chromatography/capillary zone electrophoresis. M.M. Bushey and J.W. Jorgenson.

A comprehensive two-dimensional (2-D) separation system utilizing reversed-phase (RP) chromatography as the first dimension separation and capillary zone electrophoresis (CZE) as the second dimension separation is presented. Effluent from the RP column, operated under gradient conditions, fills a loop on a computer-controlled six-port valve. A second pump flushes this loop material over the grounded (anode) end of a CZE capillary at specific intervals. Electromigration injections are performed on the CZE portion of the system from a flowing stream. Fluorescence detection is used on the CZE capillary. The system is used for the analysis of peptide standards and fluorescently labeled peptide products from a tryptic digest of ovalbumin. The 2-D system has a much greater resolving power and peak capacity than either of the two systems used indepen- dently of each other. The entire system is automated and operated under computer control. Three-dimensional data representation provides a means of viewing peak profiles in either separation dimension, and contour mapping of the 3-D data provides a ,,fingerprint" of protein digests. - Anal. Chem. 62, 978 - 984 (1990). Dept. Chem., Univ., Chapel Hill, NC (USA)

A new valve for zone electrophoretic sample treatment coupled on-line with high-performance liquid chromatography. A.J.J. Debets, K.-P. Hupe, U.A.Th. Brinkman and W.Th. Kok.

The design of a new valve arrangement for zone-electrophoretic sample treatment (ZEST) coupled on-line with HPLC is described. Characteristics of this valve, such as the internal heat development as a function of the current, have been investigated. By using quinidine and desipramine as model compounds it is shown that charged compounds can be isolated from biological samples, in about 15 rain, with high selectivity. The carry-over of proteins to the analytical column has been compared with the carry-over using a pre-column sample clean-up method. The detection limits of quinidine and hydroquinine (50 ng/ml), using zone-electrophoretic sample treatment coupled with column liquid chromatography, are in the same range as with direct injections using pre-columns. - Chromatographia 29, 217-222 (1990). Dept. Anal. Chem., Free Univ., Amsterdam (NL)

Capillarelektrophorese. H.-J. Schneider. Es wird eine einfache YObersieht fiber die Methode und verschiedene

Teehniken in tier Capillarelektrophorese gegeben. - Labor-Praxis 13, (10), 868-869 (1989). Beckmann Instruments GmbH, Mfinchen (D)

M. Rittich

Design of a variable wavelength UV absorption detector for on-column detection in capillary eleetrophoresis and comparison of its performance to a fixed wavelength UV absorption detector. J.S. Green and J.W. Jorgenson.

The design, sensitivity, and noise characteristics of a deuterium lamp based variable wavelength UV absorption detector for capillary zone electrophoresis are described. This detector is compared to a previously described fixed wavelength detector which has been alternately fitted with a cadmium, zinc, and experimental arsenic lamp. - J. Liquid Chromatogr. 12, 2527-2561 (1989). Dept. Chem., Univ., Chapel Hill, NC (USA)

Preliminary investigation of ion mobility spectrometry after capillary electropboretic introduction. R.W. Hallen, C.B. Shumate, W.F. Siems, T. Tsuda and H.H. Hill, Jr.

Using standard capillary electrophoretic and ion mobility methods, several electrospray interface designs were investigated for the capillary electrophoretic introduction of samples into the ion mobility spectrometer. Of the interfaces investigated, the flow assisted interface and the direct coupled interface showed the most promise. These preliminary experiments were encouraging. The ion mobility spectrometer coupled with a capillary electrophoretic introduction system operated with excellent separation efficiency and ion mobility reproducibility. Using tetrabutylammonium iodide, the number of theoretical plates for the spectrometer was calculated to be 3.103 and reduced mobilities were found to be reproducible with a relative standard deviation of 1.43%. Because of the desire to hold the spectrometer as hot as possible, the solvent would often vaporize in the interface, creating an unstable spray and inhomogeneities in the electrophoretic field. More work is needed to improve the spray process which contributed to the overall noise of the system and to eliminate the phenomenon of solvent vaporization which limited the reproducibility of electrophoretic migration times. - J. Chromatogr. 480, 233-245 (1989). Dept. Chem., State Univ., Pullman, WA (USA)

Electroosmotic flow and electric current in capillary electrophoresis. T. Tsuda.

In capillary electrophoresis, the production of heat is inevitable an result of high voltage. Current density is a most reliable factor for understanding the relation with eleetroosmotic flow, apparent mobility and the number of theoretical plates. Equations for these matters have been derived. Effects of electrolyte concentration on electroosmotic flow is also discussed. The change in direction of electroosmotic flow due to the sign of surface charge is demonstrated. - J. Liquid Chromatogr. 12, 2501-2514 (1989). Nagoya Inst. Technol., Gokiso, Showa, Nagoya (J)

Capillary electroseparation methods looking into the crystal bail. J.H. Knox and K.A. McCormack.

The nature of the four capillary electroseparation (CES) techniques are discussed in relation to the basic theory of electrophoresis, electroendosmosis and partition. The limitations and the pitfalls likely to be encountered in practice are discussed: in particular we emphasise the avoidance of self-heating, the preservation of a uniform wall, and the problems of coupling narrow bore tubes to the separation capillary. The special requirements which have to be met in the design of detectors for CES are discussed and some design improvements are proposed. - J. Liquid Chromatogr. 12, 2435-2470 (1989). Dept. Chem., Univ. Edingburgh (GB)

Semiconductor radioisotope detector for capillary electrophoresis. S.L. Pentoney, Jr., R.N. Zare and J.F. Quint.

A simple, semiconductor radioactivity detector for capillary electrophoresis is described. The capillary electrophoresis-radioisotope detector system utilizes a commercially available semiconductor device which is positioned external to the separation channel and which re- sponds directly to impinging 7 or high-energy [3 radiation. The system performance is evaluated using synthetic mixtures of 32P-labeled sample molecules and the efficiency of the semiconductor detector (planar ge- ometry) is determined to be approximately 26%. The detection limit is determined to be in the low nanocurie range for separation performed under standard conditions (an injected sample quantity of 1 nCi corre-


sponds to 110 • 10 t8 moles of 32p). The lower limit of detection is extended to the sub-nonocurie level by use of flow (voltage) program- ming to increase the residence time of labeled sample components in the detection volume. - J. Chromatogr. 480, 259 - 270 (1989). Dept. Chem., Univ., Stanford, CA (USA)

Simple apparatus for capillary zone electrophoresis and its application to protein analysis. V. Rohli~ek and Z. Deyl.

The construction of a simple apparatus for capillary zone electrophoresis is described, consisting of an optical system allowing direct absorbance measurement in the capillary in UV light, an evaluating electronic module and a high-potential source. An attempt was made to achieve maximum sensitivity with a simple construction. In the elec- tronics, care was taken to obtain a quiet baseline and to optimize the signal-to-noise ratio. That part of the noise which is of the frequency band of the signal is filtered off. Both suction and electrophoretic sample introduction are possible. According to operator's choice, the apparatus can be run under constant voltage or current an is protected against overloading. The high-potential electrode chamber contains separate buffer and sample compartments and its construction offers an easy interchange between the running and sampling positions. The applica- bility of the system to the separation of amino acids as phe- nylthiocarbamyl derivatives, pepfides and both artificial and naturally occuring protein mixtures is demonstrated. - J. Chromatogr. 494, 8 7 - 99 (1989). Inst. Physiol., Acad. Sci., Prague (CS)

Simultaneous two-color thermo-optical absorbance detector for capillary zone electrophoresis. C.W. Earle and N.J. Dovichi.

A novel crossed-beam thermo-optical absorbance detector for capillary zone electrophoresis is constructed that measures absorbance simultaneously at two wavelengths. This detector uses two lasers, modulated at different frequencies, to both generate and to probe a thermo-optical signal within the capillary. Two lock-in amplifiers are used to demodulate the two-color thermo-optical signal. The technique is demonstrated for both static samples and a simple capillary zone electrophoresis separation. - J. Liquid Chromatogr. 12, 2575-2585 (1989). Dept. Chem., Univ., Edmonton, Alb. (CDN)

Electrophoresis in an expanded stationary boundary. B.M. Michov. A method of electrophoresis in an expanded stationary boundary is

described, in which a pH gradient formed in a single buffer is used. The degrees of ionization and the concentrations of the electrolytes have values at which the polyions stack and resolve simultaneously in a polyacrylamide gel. To illustrate the method, the resolving of serum proteins in a pH gradient formed by Tris-glycinate buffer is con- sidered. - Electrophoresis 11,289-292 (1990). Dept. Biochem., Acad. Med., Sofia (BG)

Steady state electrolysis and isoelectric focusing. R. Hagedorn and G. Fuhr.

The properties of pH gradients formed by stationary electrolysis of weak mobile or fixed electrolytes are analyzed. The model uses the appropriate balance equations and those of chemical equilibria. It is shown how the equation of the current density has to be modified for considering that fraction of current that is associated with the diffusion of neutral buffer molecules within a pH gradient. Furthermore it is shown that the pH gradients themselves give rise to water production within the gradient and that essential properties of the steady state are related to chemical reactions between the electrolyte constituents. The differential equations describing the gradients of the concentration of a given component, the pH, conductivity and potential are explicitly formulated in relation to those reactions. The equations are solved numerically and the significance of the results for isoelectric focusing is discussed. The experimental conditions to reach shallow and smooth pH gradients exhibiting sufficient ionic strength are formulated. - Electrophoresis 11, 281--289 (1990). Dept. Biol., Humboldt-Univ., Berlin (D)

Pouring wide-range immobilized pH gradient gels with a window of extremely flattened slope. K. Altland and A. Altland.

A gradient mixing device has been designed to pour polyacrylamide gels with a wide-range immobilized pH gradient including a "window" of extremely flattened slope. The device consists of an IBM-compatible personal computer controlling 8 step-motor-driven burettes, with four producing a density gradient from glycerol and delivering acrylamides and catalysts for gel polymerization, two delivering Immobilines for a wide-range pH gradient and the other two burettes responsible for the delivery of Immobilines for a partial pH range inside the wide range. The effect on a complex separation pattern of proteins with a wide range of pI is that resolution can be increased reproducibly to any reasonable extent at any location of the separation pattern. - Electrophoresis 11, 337-343 (1990). Inst. Human Genetics, Univ., Giessen (D)

Giant two-dimensional gel electrophoresis: Methodological update and comparison with intermediate-format gel systems. R.M. Levenson, G.M. Anderson, J.A. Cohn and P.J. Blackshear.

Two-dimensional (2-D) gel electrophoresis methods for separating complex mixtures of proteins have not changed fundamentally since their original description in the late 1970's. Nevertheless, 2-D gel resolution has improved substantially as a result of a series of incrementai modifications. One of these was the development of the "giant-gel" format, using gels measuring at least 30 × 30 cm to provide the highest resolution 2-D gel system available. As orginally described, this procedure has several important limitations: it requires custom-built equipment; it is expensive in terms of time, reagents, film and support matrices; and it generates gels which are difficult to manipulate, particularly for silver staining. This report describes modifications in the giant gel procedure to permit use of a commercially available gel apparatus and to obtain giant gels of improved mechanical strength suitable for silver staining. The resolution of giant gels is compared with that obtained using two systems currently being marketed for use by laboratories performing large numbers of 2-D gel analyses. The smaller format gels resolved fewer proteins, by 3 0 - 40%, compared with the giant gels. This difference in resolving power suggests that giant gels will continue to be useful in selected appi ica t ions . - Electrophoresis 11, 269-279 (1990). Howard Hughes Med. Inst. Labs., Durham, NC (USA)

Reagentless electroosmotic preconcentration for ionometric determination of anions. L.N. Moskvin, L.V. Epimakhova, V.M. Krasnoperov and V.S. Gurskii.

10 -4 . - 10 5 tool/1 Anionen in der L6sung k6nnen mittels der ionenselektiven Elektroden (ISE) in der Regel ohne Schwierigkeiten direkt potentiometrisch bestimmt werden; ihre Bestimmung in niedrigeren Konzentrationen ist dagegen bloB nach vorausgehender Anreicherung m6glich. Zu diesem Zweck wurde die beschriebene Methode der reagens- losen elektroosmotischen Anreicherung von C1- und NO3- ausgearbeitet, die in einer 20 ml-Teflonzelle mit durch por6se Membran (Fl[iche •2,6 cm 2) getrennter anodischer und kathodischer Kammer (schem. Abbildung s. Original) durchgef/ihrt wird, Die Membran mit negativer Ladung wird auf tier Basis der Acetylcellulose Millipor (USA; Poren- durchmesser 0,7 ~m) bzw. Vladipor (SU; Porendurchmesser 1,2 ~m) hergestellt. In der Zelle werden zwei Pt-Elektroden mit eingelegter Span- hung 500 - 600 V eingeschaltet; die Probe wird in die Zeile mit Hilfe der Mariotteschen Flasche dosiert. Nach der Einschaltung des elektrischen Feldes wandert das Wasser aus dem anodischen Raum infolge der Osmose in den kathodischen mit der Geschwindigkeit 3 1/h. Innerhalb von 3 0 - 4 0 rain k6nnen auf diese Weise die Anionen im anodischen Raum angereichert werden; Anreicherungskoeffizient ~ 1 0 z bei An- fangskonzentration 10 - s - 10 -7 tool/1. Die Verl~iBIichkeit dieser Me- rhode wurde durch die Methode des Standardzusatzes der KC1-L6sung mit 36C1- nachgepriift. Bei der Bestimmung yon 35 rag/1 CI- entspricht der Bestimrnungsfehler h6chstens 0,•7, bei der Bestimmung yon 62 mg/1 NO3- 0 , 1 1 . - Zh. Anal. Khim. 44, 1995-1997 (•989) (Russisch, mit engl. Zus.fass.). F. Jancik

Infrared spectroscopic determination of pH changes in diffusionally decoupled thin-layer electrochemical cells. [.T. Bae, D.A. Scherson and E.B. Yeager.

In situ Fourier transform reflection absorption infrared spectroscopy has been employed as a probe of the local pH in the thin layer of electrolyte solution trapped between the electrode and the optical win-

658 i General analytical chemistry

dow. The method is based on the differences in the spectral properties of certain bases and their conjugated acids, which makes it possible to determine pH changes on the basis of the relative integrated intensities of the two species. Illustrations are given for the carbonate/bicarbonate and acetate/acetic acid systems and the oxidation of CO in alkaline media. - Anal. Chem. 62, 45-49 (1990). Case Cent. Electrochem. Sci. Dept. Chem., Case West Reserve Univ., Cleveland, OH (USA)

Development of microcomputer-controlled pulse polarograph. T. Kakizaki, S. Hikima and K. Hasebe.

Ein elektroanalytisches System mit einer preiswerten Mikrocomputer- Oberwachung wird beschrieben. Es verwendet einen Personal-Computer mit einem Interface-Board und einem selbstgemachten Potentiostat ohne weitere analoge oder digitale Extrastromkreise. Software fiir die Hand- habung wird hergestellt. Das vorgeschlagene polarographise System mit Mikrocomputer-Steuerung wird hier zur Bestimmung von TI(I), Cd(II) und In(III) in 0,1 mol/1 KC1 eingesetzt. Die Polarogramme werden mit dem Personal-Computer ausgewertet. Unter leichter Verfinderung der Software kann das System auch ffir voltammetrische Messungen eingesetzt werden. - Anal. Sci. 5, 781-782 (1989). Lab. Chem., Hokkaido Univ. Educ., Iwamizawa (J) R.H.S.

Use of mercury containing Zeolite A layers on glassy carbon for differential-pulse anodic stripping voltammetry. J. Cassidy, E. O'Donoghue and W. Breen.

Layers consisting of Hg2+-exchanged Zeolite A and polystyrene formed stable coatings on glassy carbon electrode surfaces. After reduction, the Hg was used for differential-pulse anodic stripping voltammetry and the layers exhibited size-exclusion properties that pre- vented the adsorption of large organic molecules. - Analyst 114, 1509 - 1510 (1989). Dept. Chem., Inst. Technol., Dublin (IRL)

Metal speciation of polyelectrolytic systems by differential pulse anodie stripping voltammetry (DPASV). M. Estaban, H.G. De Jong and H.P. Van Leeuwen.

Eine Reihe yon Metall/Polyelektrolyt-Komplexen wird mit Hilfe der DPASV untersucht, wobei die grogen Unterschiede den Diffusionskoef- fizienten yon freiem und komplexiertem Metall ausgenutzt werden. Zink- Polymethacrylat, Cadmium-Polymethacrylat und Zinkpolyacrylat-Sy- steme sind unter DPASV-Bedingungen labil. In einem weiten Bereich yon Metall: Ligand-VerMltnis k6nnen die DPASV-Peaks erfolgreich mit Hilfe der mittleren Diffusions-Koeffizienten Ib analysiert werden. Diese I3-Werte hfingen direkt mit der Stabilit/it der Komplexe zusammen und erlauben daher ein Unterscheiden des Metalls in freier und komplexierter Form. Ffir Pb- und Cd-Polyacrylate ist die VerS.nderung der H6he der DPASV-Peaks mit der Polyionkonzentration nicht auf der Grundlage der Unterschiede der Diffusionskoeffizienten und yon Assoziation/Dias- soziation des Komplexes erkl/irbar, diese Systeme sind komplizierter, so dab weitere Untersuchungen zur Erkl/irung dieser Systeme erforderlich sind. - Intern. J. Environ. Anal. Chem. 38, 75-83 (1990). Dept. Quire. Anal., Univ., Barcelona (E) R.H.S.

Reshaping of staircase voltammograms by discrete spherical convolution. S.O. Engblom and K.B. Oldham.

Linear-scan staircase voltammetry and cyclic staircase voltammetry generate unsatisfactory current-voltage curves even for reversible electrode processes. A convolution method is described that converts such curves, obtained at spherical mercury electrodes, into the classical wave shape that is familiar from polarography. The plateaus of these wave are horizontal and their heights accurately match theorectical prediction. - Anal. Chem. 62, 625-630 (1990). Dept. Chem., Trent Univ., Peter- borough, Ontario (CDN)

Theory for cyclic staircase voltammetry for first-order coupled reactions. M.M. Murphy, J.J. O'Dea, D. Arn and J.G. Osteryoung.

A systematic computational study of three first-order kinetic systems has been performed for cyclic staircase voltammetry. The systems are electrochemically reversible but complicated by a preceding, following, or catalytic chemical reaction. Theoretical working curves have been calculated and the variation in peak currents and peak potentials with a change in rate parameter for the chemical step has been compiled in

graphical form. The results resemble, but differ quantitatively from, those for square wave and linear scan (cyclic) voltammetry. It is suggested that reverse current be measured with respect to the zero of current. - Anal. Chem. 62, 903 -909 (1990). Dept. Chem., SUNY Univ., Buffalo, NY (USA)

In-situ electron spin resonance and voltammetric studies using an internal- flow-type electrolysis cell. K. Kano, K. Mori, T. Konse, B. Uno and T. Kubota.

A newly designed three-electrode electrolysis cell for in-situ electron spin resonance (ESR) spectroscopy and cyclic voltammetry is described. An electrolysis solution near the electrode surface is continuously re- newed by an internal-flow method, which makes it possible to record the well-resolved ESR spectra of unstable free radicals. An accurate control of the electrode potential using an ohmic drop corrector has enabled us to obtain a fairly good voltammogram. This cell can be applicable to both oxidation and reduction experiments in aprotic and protic media at an arbitrary temperature by use of a temperature-controlled Dewar vessel. Some fundamental experiments are reported. - Anal. Sci. 5, 651-656 (1989). Gifu Pharm. Univ., Mitahora-higashi, aifu (J)

A solid-state reference electrode based on bilayer coating with poly(p,p'- biphenol) and polyimide films for the gate of field effect transistor. N. Oyama, T. Ohsaka, S. Ikeda and K. Okuaki.

A solid-state reference electrode has been fabricated. Its design is based on a field effect transistor, the gate of which is coated with two kinds of polymeric films in a bilayer state: the inner layer is an electroactive electropolymerized poly(p,p'-biphenoI) film and the outer one is a polyimide film. The electrode characteristics have been examined. The bilayer film~coated reference field effect transistors (RFETs) thus fabricated were intensive to electrolyte ions (including H + and OH ) under the condition of a constant concentration (e.g., 0.1 M) of an electrolyte; thus they could function as a reference electrode. These RFETs showed insensitivity to 02 and less sensitivity to CO2 (compared with the RFET coated with the polyimide film alone), long-term stability and little drift. The results demonstrate that the bilayer film-coated FETs are promising as a solid-state reference eIectrode coupled with conventional ion-sensitive field effect transistors in a biological system. - Anal. Sci. 5, 729-734 (1989). Dept. Appl. Chem., Fac. Tcchnol., Tokyo Univ. Agric. Technol., Koganei, Tokyo (J)

Electrochemical activation of carbon electrodes in base: minimization of dopamine adsorption and electrode capacitance. D.M. Anjo, M. Kahr, M.M. Khodabakhsh, S. Nowinski and M. Wanger.

A study has been made of the optimum conditions for electrochemical • activation of carbon electrodes used in the analysis of dopamin~. The conditions optimized were electrolyte pH, activation voltage, and the duration of the activation. The parameters monitored during the optimization were the reversibility of the dopamine couple, electrode capacitance, and dopamine adsorption. It was found that both the capacitance and dopamine adsorption decreased as the pH of the electrolyte was increased. The optimum conditions found for electrochemical activation were a pH of 13, a potential of 1.2 V (SCE) for a duration of 5 rain. These activation conditions were then applied to a number of glassy carbons and a pyrolytic carbon film electrode. - Anal. Chem. 61, 2603 -2608 (1989). Dept. Chem. Biochem., State Univ., Long Beach, c a (USA)

Electrochemical characterization of a microcellular carbon foam/epoxy composite electrode. B.K. Davis, S.G. Weber and A.P. Sylwester.

The construction of a microcellular carbon foam/epoxy resin composite electrode is described. The large perimeter-to-area ratio (P/A) of the resulting microelectrode array is desirable and represents an improvement in P/A over that of many composites presently in use. The array is characterized by using chronoamperometry and cyclic voltammetry. The results are compared to those of both a glassy carbon electrode and microelectrode array theory. The responses obtained are representative of expected behavior. The capacity of the electrode was 2.1 x 103 gF/ cm 2, 2 orders of magnitude greater than that expected for carbon. -


Anal. Chem. 62, 1000-1003 (1990). Dept. Chem., Univ., Pittsburgh, PA (USA)

Microemulsion structure and its effect on electrochemical reactions. R.A. Mackay, S.A. Myers, L. Bodalbhai and A. Brajter-Toth.

Changes in the microstructure of oil-in-water microemuisions were identified electrochemically by using ferrocene derivatives, methyl viologen, and ferricyanide as the electroactive probes. Microdroplets as well as the bicontinuous microstructure were detected. This was accomplished by determining diffusion coefficients of the probes. Use of probes of different hydrophobicity/hydrophilicity and charge made it possible to investigate different microenvironment of microemulsions including oil, water, and surfactant/eosurfactant interface. Electrochemi- cal reversibility of the probes was affected by the structure and appeared to reflect the ease of mobility across interphases. Reaction potential (E~/2) of the probes depended on the composition of the microemulsion. Anal Chem. 62, i084-1090 (1990). CRDEC, U.S. Army, Aberdeen Proving Ground, MD (USA)

Using dispersion staining colors and glass standards of known refractive index to determine the refractive index of liquids. P.F. Lott.

A method has been developed for measuring the refractive index of liquids microscopically that employs glass reference standards of known refractive index and dispersion staining. The dispersion staining color is converted to a refractive index value that is added (or substracted) to the refractive index value of the glass standard to obtain the refractive index of the liquid. The method is particularly suited for quality control checking of the refractive index of those immersion oils used in the detection and identification of asbestos by polarized light microscopy. - Microchem. J. 40, 331-334 (1989). Chem. Dept., Univ., Kansas City, MO (USA)

Current status and prospects for the use of optical fibres in chemical analysis. A review. J.O.W. Norris.

Introduction. Perceived advantages and disadvantages; advantages, disadvantages. Underlying principles of fibre optic sensors. Optical effects, chemical equilibria. Instrumentation: Method for classifying fibre optic sensors. Description of some sensors. Extrinsic species-specific sensors, remote spectroscopy, sensors utilising immobilised reagents, intrinsic species-specific devices, evanescent wave devices, non-species- specific techniques, indirect techniques. Conclusions, references. - Ana- lyst 114, 1359-- 1372 (1989). Mater. Dev. Div., HarwelI Lab. AEA Tech- nol., Oxfordshire (GB)

Robust statistics - how not to reject outliers. Part 1. Basic concepts. Analytical Methods Committee.

The subject of outliers has been controversial whenever analytical data have been processed. Modern statistical theory provides an alternative to outlier rejection, in which outlying observations are retained but given less weight. This approach is known as robust statistics and is beginning to find favour with analytical chemists. An introduction to robust statistics is given and some examples are described. -

Part 2. Inter-laboratory trials. Robust statistics can be used to find estimates of true values and

precision that are insulated from the effect of outliers. In this paper these procedures have been extended to inter-laboratory trials. - Analyst 114, 1693-1697, 1699-1702 (1989). Royal Soc. Chem., Piccadilly, London (GB)

Aspects of the analysis of three-way data. L. St~thle. An algorithm is developed for linear three-way decomposition (LTD)

of three-way tables for the case of one dependent block of variables and one independent, predictor block. The algorithm is a generalization of the two-block partial least squares (PLS) algorithm. Using simulation and real data LTD is compared with multi-way PLS with and without decomposition of the weight matrix. LTD and PLS with a one-dimensional decomposition of the weight matrix gives essentially the same results. By means of the cross-validation criterion it is shown that, in practice, optimal prediction may be obtained with a model that is neither completely trilinear nor bilinear. The multi-way PLS method with decomposition of the weight matrix to give the minimum cross-validation

prediction error is preferred. - Chemometrichs Intell. Lab. Systems 7, 95-100 (1989). Dept. PharmacoI., Karolinska Inst., Stockholm (S)

Multivariate rule building expert system. P. de B. Harrington and K.J. Voorhees.

A multivariate rule building expert sytem (MuRES) has been devised that acquires knowledge in the form of rules from training sets of multivariate analytical data. MuRES differs from conventional expert system in that it generates rules that consist of a linear combination of all variables. MuRES advantageously combines the robust character of univariate expert systems and the feature transformatin properties of linear classifiers. MuRES develops its own certainty factors and provides qualitative information regarding the classification. When evaluated with exemplary data, MuRES performed better than linear discriminant analysis, soft independent modeling of class analogy, and a univariate expert system. -- Anal. Chem. 62, 729-734 (1990). Dept. Chem. & Geochem., Colorado School of Mines, Golden, CO (USA)

Reliability of repeatability and reproducibility measures in collaborative trials. K.F. Karpinski.

The acceptability of a new analytical method is generally assessed in terms of repeatability and reproducibility etimates derived from a collaborative study. Procedures are presented for calculating confidence intervals and operating characteristic curves for acceptance criteria based on the repeatability and reproducibility estimates. Comparisons of the reliability of estimates are provided for various numbers of collaborators. With a small number of collaborators, the estimates of reproducibility are not reliable and decisions regarding acceptability of a method will be heavily based on the method's repeatability rather than the property of most interest, namely, the reproducibility of the method. - J. Assoc. Off. Anal. Chem. 72, 931--935 (1989). Health Welfare Canada Health Protect. Branch, Food Statist. Operat. Plann. Div., Ottawa, Ontario (CDN)

General least-squares smoothing and differentiation by the convolution (Savitzky-Golay) method. P.A. Gorry.

Smoothing and differentiation of large data sets by piecewise least- squares polynomial fitting are now widely used techniques. The calculation speed is very greatly enhanced if a convolution formalism is used to perform the calculations. Previously tables of convolution weights for the center-point least-squares evaluation of 2m + 1 points have been presented. A major drawback of the technique is that the end points of the data sets are lost (2m points for a 2m + ] point filter). Convolution weights have alos been presented in the special case of initial-point values. In this paper a simple general procedure for calculating the convolution weights at all positions, for all polynomial orders, all filter lengths, and any derivative is presented. The method, based on the recursive properties of Gram polynomials, enables the convolution technique to be extended to cover all points in the spectrum. - Anal. Chem. 62, 570- 573 (1990). Dept. Chem., Univ., Manchester (GB)

Computer steuern Analysenmeflger~ite. K. Winter. Das System IDA verwaltet, iiberwacht und wertet die in Laboratorien

anfallenden Daten aus und ist eine Kombination yon LIMS (Computer- system ffir Datenhandling im Labor) und Inseln (Dialogschnittstellen yon Analysenautomaten mit eigener Software). Es tester formale Kor- rektheit der registrierten Proben und daraus resultierende Analysenauf- tr/ige, reiht die Auftr/ige in Warteschlangen ein, von wo sic zusammen mit den Steuerparametern an die Arbeitspl/itze gelenkt werden. Die Resultate werden fibernommen und dem Verwaltungssystem iibergeben, mit Hilfe von Stammdatens/itzen fiberprfift find statistisch aufbereitet. - LaborPraxis 13(I0), 763 - 764. Ingenieurbfiro Degner & Weber, Witten (D) W. Schmidt

1.2 Inorganic analysis

Electrolyte dropping electrode polarographic studies. Solvent effect on stability of crown ether complexes of alkali-metal cations. Z. Samec and P. Papoff.

660 I General analytical chemistry

A simple three-electrode polarographic assembly with the electrolyte dropping electrode for the study of the ion transport across a liquid- liquid interface was presented. Transfer of alkali-metal cations from water to nitrobenzene (NB) or 1,2-dicholoroethane (I,2-DCE) facilitated by complex formation with dibenzo-18-crown-6, dibenzo-24-crown-8, or dibenzo-30-crown-10 was studied. Experimental current vs potential data were used to clarify the mechanism of the ion-transport and to evaluate the stability constants of crown ether complexes. The stability constants are l0 s - 107 larger in NB and 10 ~° - 10 ~2 larger in 1.2-DCE than those in water. The selectivity sequence changes with the solvent, comparing water (K + > Na ÷ > Rb + > Cs +) with NB (Na + > K* > Rb + > Cs +, Li +) and 1,2-DCE (Li + > Na ~ > K + > Rb + > Cs +). Solvent effects can be understood in terms of differences in cation solvation, which plays a dominant role in low polar media. - Anal. Chem. 62, 1010-1015 (1990). Ist. Chim. Anal. Strumentale des CNR, Pisa (I)

Extraktionszeiten bringen nichts; Temperaturen zwischen 20 und 45°C beeinflussen die Au-Extraktion nicht, jedoch nimmt die Stabilitfit des Komplexes mit steigender Temperatur ab (Sommer bei 40+2°C nur noch 5 min!). Gemessen wird gegen Reagentienblindwert bei 395 nm. Nachweisbarkeitsgrenze 0,1 ~tg Au/ml; das Beersche Gesetz wird im Bereich 4,0-48,0 ppm Au erffillt; relative Standardabweichung bei 24 ppm Au _+ 0,8%. Anwendung des Verfahren zur Analyse yon Sonakhan- Erzen mit 1,5-2,2 ppm Au. S 2 , SO32- st6ren; <3 M HCI wird Pd mitextrahiert und st6rt; h6here Fe(III)-Gehalte (50 mg) sind nut bei geringerer Aciditfit tolerierbar, ferner bei 600 ~tg Au/15 mh 200 mg Mn(II), Zn(II); 150 Ni(II); 100 Cd(II), Cr(III), Cu(II), Th(IV), U(VI); 80 AI(III); 60 Co(II); 40 Zr(IV); 35 Pb(II); 20 Ti(IV); 15 Os(III), Ru(III); 10 Pt(IV), Ir(IV), Mo(VI); 8 Bi(III); 6 Sb(III); 5 Fe(III), Pd(II), Nb(V), Ta(V), V(V), W(VI); 2 Re(VII); 100 PO43-, AsO43-; 150 C2042-. - Analusis 17, 540 542 (1989). Dept. Chem., Ravishankar Univ., Paipur, M.P. (IND) G. Preis

Spectrophotometric study on complexation reaction of copper(II) with N- (4-hydroxy-3-methoxybenzylidene) hydrazine carbothioamide. H.S. Gow- da, S.M. Ahmed and K.S. Jagadeesh.

Cu(II) reacts with N-(4-hydroxy-3-methoxybenzylidene)hydrazine carbothioamide to form an orange-yellow complex suitable for spectrophotometry of the metal at pH 9.3 - 11.6 (phthalate buffer). The complex shows Lm~x at 410 nm (a 1.23 x 104) and obeys Beer's law from 0.1--3.2 ppm of Cu concentration. In determination of 1.5 ppm, the following ions (in ppm) do not interfere: F (8500); CI-, Br- (9000); I - (860); NO3-, $2032 (10000); SO42- (8000); CzO42- (80); tartrate, citrate (7000); PO43 (3500); EDTA (160) Ag(3); Mg (24); Ca, Ba (10); Sn2+ (27); Pb (24); Mn 2+ (100); Co 2+, Ni 2+ (0.5); Zn (20); Hg 2+ (36); A1 (24); As 3+ (104); Sb 3+ (16); Bi 3+ (6); Cr 3+ (146); Fe 3+ (6); Au 3+ (5); Sn 4+ (32); Ti 4+ (1.5); V 5+ (40); Te 6+ (31) and U 6+ (30). The method is applied to determine Cu in its alloys. - J. Indian Chem. Soc. 66, 915-917 (1989). Dept. Chem., Central College, Bangalore (IND)

H.B. Singh

Ultrafiltration study of silver(I) and copper(II) complexation with macroligands derived from polyacrylic acid and study of their separation. K. Ennassef, M. Persin and G. Durand.

Two macroligands derived from polyacrylic acid have been used to study ultrafiltration separation of silver(I) and copper(II). The first part is devoted to study of acid-base and complexometric properties of two macroligands polyacrylic acid and dispersant G. The exploitation of acid-base titrations curves by sodium hydroxide in presence of increasing quantities of metallic cations has allowed to show and calculate formation constants of i : 1 complexes for silver and copper and 1 : 2 for copper. A second part is devoted to utilization of ultrafiltration as a means of solution study. Formation constants of copper(II) and silver(I) complexes with two macroligands and complexometric titration curves have been obtained by this method and compared with precedent results. Finally, after study of physicochemical factors which influence reject rate, separation by ultrafiltration of the two cations has been done. - Analusis 17, 565-575 (1989). Lab. Chim. Electrochim. anal., ENSCM, Montpellier (F)

Extraction of gold(III) with various amidines: spectrophotometric determination of gold in low grade ores. N. Mishra, K.S. Patel and R.K. Mishra.

Verff. testen 9 Amidine zur extraktionsphotometrischen Bestimmung von Au(III) in Gegenwart von Bromid-Ionen (Bromo-Aurat-Komplex). Die Amidine werden durch Kondensation fiquimolarer Anteile N- Phenyl/-substituierter Benzimidoylchloride mit N-Phenylamin syntheti- siert. Angewendet wird eine 0,2% (w/v)-L6sung in CHCI3. Arbeitsweise. 7 ml 10 M HC1 und 3 ml 2,5 M KBr-L6snng werden zu einem Aliquot mit 25-1300 gg Au(III) in einen 150 ml-Scheidetrichter gegeben und mit dest. HzO zu 15 ml ergS~nzt; 2 rain mit 15 ml CHC13-Amidin sch/it- teln; Extrakt in 25 ml-Becherglas fiber 2 g Na2SO4, wasserfrei, trocknen. W/igrige Phase 3 x mitje 2 ml CHC13 nachwaschen; alle Extrakte nach dem Trocknen in 25 ml-Megkolben fiberfiihren und mit CHC13 zur Marke erg~inzen. Die Extraktion yon Au(III) ist ~> 99,5% ; Absorptions- bereich 390-395 nm. N-Phenyl-N-octylbenzamidin (POBA) gibt die st~irkste Farbreaktion. Der POBA-Komplex ist im Bereich 0,01 --11 M HCI quantitativ extrahierbar und bei 27 _+ 2°C 1 Stunde haltbar. L/ingere

A study of modifiers for the determination of beryllium by graphite furnace atomic absorption spectroscopy. L. Fangruo, L. Xiaoying and W. Mohui.

A method has been developed to determine trace Be in samples of stream sediment by stabilized temperature platform furnace (STPF) AAS in an acid mixture of HF and HNO3, using Al(NO3)3 as the modifier. The digested sample is sealed in a Teflon bomb and heated by microwave radiation. The Be values determined in the standard reference materials (SRM) show good agreement with the certified values. For ten replicates of one standard SRM, the certified value is 1.1 ppm, the average of determined values by this method is 1.16 ppm, the relative standard deyiation is 2.8%, and the characteristic mass for Be is 0.73 pg/0.0044 A.s. This method is very simple, rapid and efficient. - At. Spectrom. 11, 78-82 (1990). Chengdu Rock Min. Res. Lab., Chengdu, Sichuan (RC)

Design of a calcium-selective optode membrane based on neutral iono- phores. W.E. Morf, K. Sefler, B. Rusterholz and W. Simon.

A large variety of new optical ion-sensor constructions (optodes) can now be realized by using a poly(vinyl chloride) (PVC) membrane that incorporates a cation-selective neutral ionophore, a specially tailored H+-selective neutral chromoionophore, and lipophilic anionic sites in the same plasticized PVC membrane. Such membranes generally com- bine the advantages of a highly selective and reversible recognition of given ionic substrates and of a straightforward optical transduction of the recognition process. The present membrane exhibits the theoretically expected absorbance response to Ca 2 ÷ activities in different pH,bufferd samples. Dynamic range, reproducibility, response time, long-time stability, and selectivity of the new optode membrane are discussed. - Anal. Chem. 62, 738-742 (1990). Swiss Fed. Inst. Technol. (ETH), Dept. Org. Chem., Zfirich (CH)

Trifluoroethylxanthate as an analytical reagent: AAS of zinc, antimony and lead after coprecipitation of their trifluoroethylxanthates onto microcrystalline naphthalene. M.F. Hussain, M. Katyal, B.K. Purl and Y. Takagi.

Ein empfindliehes Verfahren zur direkten AAS-Bestimmung yon Zn, Sb und Pb nach Mitffillung in Form ihrer Trifluoroethylxanthate auf mikrokristallinem Naphthalin wird beschrleben. Dazu werden die pH- Werte der Probel6sungen mit wfil3rigem Ammoniak oder Perchlors/iure eingestellt. Die Metallxanthate werden quantitativ in folgenden pH- Bereichen geffillt: Zn 5,9-.8,4, Sb 4,0-6,0 und Pb 4,0-11,0. Die feste Masse besteht aus dem Metallkomplex und Naphthalin, diese wird gel6st in DMF. Die entstehende L6sung wird in die Luft/Acetylen-Flamme gesprfiht und dann bei 213,9 nm ffir Zn, bei 217,6 nm ffir Sb und bei 2/7,0 nm ffir Pb ausgewertet. Die Eichkurven sind fiir Zn im Bereich von 2 - 5 0 gg, ffir Sb von 3 - 9 0 gg und ffir Pb von 5--60 gg pro 10 ml DMF-L6sung linear. Die relativen Standardabweichungen liegen yon ± 0,5-0,6% (n = 10). Das Verfahren kann zur Vorkonzentrierung von Metallen aus gr6Beren Volumina wfil3riger Phase und zur Bestimmung in Standardreferenz-Materialien eingesetzt werden. Die gleichzeitige Be- stimmung von Zn, Pb und Sb in einer L6sung kann durch pH-Kontrolle durchgeffihrt werden. - Intern. J. Environ. Anal. Chem. 38, 525-531 (1990). Dept. Chem., Indian Inst. Technol., New Delhi (IND)

R.H.S.

1.2 Inorganic analysis 661

Determination of traces of mercury(II) and phenylmercury by direct polyurethane foam thin-layer spectrophotometry. M.N. Abbas, N.B. E1-Assy and S. Abdel-Moniem.

Verff. beschreiben ein Verfahren zur spektralphotometrischen Bestim- mung von Hg und Phenylquecksilber im ppb-Konzentrationsbereich, dessen Empfindlichkeit vor allem durch die Sorption an mit Dithizon imprfigniertem Polyurethanschaum bestimmt ist. Die Messung erfolgt nach dem yon den gleichen Verff. in Anal. Lett. 22, 1555 (1989) beschriebenen Verfahren. Dabei werden die mit dem Farbkomplex beladenen Schaumstfickchen in einer mit Ethanol geffillten 1-cm-Quarzklivette bei drei verschiedenen Wellenl~ingen (560, 485 und 400 nm) photometriert und die Netto-Absorption bei 485 nm nach Berficksichtigung der Ab- sorption des reinen Schaums und des Dithizons in Ethanol berechnet. Nachweisgrenzen: 5 bzw. 10 gg/1 Quecksilber bzw. Phenylquecksilber bei Verwendung von 100 ml-Proben. Die mittleren Wiederfindungen in Leitungswasser werden mit 100% (Quecksilber) und 96,6% (Phenyl- quecksilber) angegeben. - Anal. Lett. 22, 2575-2585 (•989). Microa- hal. Res. Lab., Nat. Res. Centre, Dokki, Kairo (ET) W. Czysz

Extraction of tervalent lanthanides as hydroxide complexes with tri-n- octylphosphine oxide. T. Cecconie and H. Freiser.

The extraction behavior of lanthanum(III), praseodymium(III), europium(III), terbium(III), holmium(III), and ytterbium(III) from dilute chloride solutions into chloroform solutions containing trim-octylphosphine oxide (TOPO) was examined. The lanthanides were found to extract as hydroxide complexes of the form Ln(OH)3"nTOPO. The extraction selectivity for this system increases with increasing TOPO concentration, rivaling those for common acidic organophosphorus extractants in the TOPO concentration range 0.025 - 0.100 M and surpass- ing them at higher concentrations. When TOPO concentrations of 0.25 M or greater are employed, the extraction system is, overall, the most selective for lanthanide separations to date. This is the first report of the lanthanides extracting as hydroxide complexes. - Anal. Chem. 62, 622-625 (•990). Strategic Metals Recov. Res. Facil., Dept. Chem., Univ., Tucson, AR (USA)

Thermal lensing detection of lanthanide ions by solvent extraction using crown ethers. C.D. Tran and W. Zhang.

A novel method has been developed to enhance the sensitivity and selectivity of the thermal lens detection of lanthanide ions. In this method, the rare-earth ions were selectively extracted from water to organic solvent with the use of crown ether, e.g., 18-crown-6, 15-crown- 5 as synergistic extractant. The thermal lens signal intensity of the extracted ions in the organic phase can be enhanced up to 24-fold. This enhancement is due to the fact that the thermal lens signal is dependent on the thermooptical properties of the solvent, and water is a poor thermooptical solvent (low dn/dT and high thermal conductivity, k, values), whereas organic solvents are good thermooptical media (high dn/dT and low k values). The well-defined cavities of the crown ethers restrict their complex formation (and hence solvent extraction) only with the rare-earth ions whose sizes are comparable to their cavities, and this is the origin for the improvement in the selectivity. For instance, with the use of 18-crown-6, up to 41% of the Er a + ion can be extracted from water to chloroform, whereas the extraction yield for the Pr 3 ÷ ion, under the same experimental conditions, was only 28%. The thermal lens technique was used to determine the stoichiometry of the extracted ion pair complexes. - Anal. Chem. 62, 830-834 (•990). Dept. Chem., Marquette Univ., Milwaukee, WI (USA)

Luminescence detection of rare-earth ions by energy transfer from counteranion to crown ether-lanthanide ion complexes. C.D. Tran and W. Zhang.

A novel method has been developed to enhance the sensitivity and selectivity of the luminescence detection for lanthanide ions. In this method, the lanthanide ion, crown ether, and benzoate were compart- mentalized into an ion pair complex in order to eliminate the quenching and to induce the energy transfer so that the luminescence detection for the lanthanide ions can be selectively enhanced. The molecular organiza- tion is achieved by using a crown ether such as 18-crown-6 or 15-crown- 5 as the synergistic extracting agent and benzoate as the counterion to selectivity extract the rare-earth ions from water into an organic solvent

where they are subsequently determined by luminescence technique. Compared to Ianthanide ions in aqueous solutions, the luminescence intensity of the extracted ion pair complexes is substantially enhanced. The luminescence intensities of the Tb 3 +, Eu a +, and Dy 3 ÷ ions were enhanced up to 4 times when they were extracted into ethyl acetate or into chloroform. This is because in water, the metal ions are quenched by the high-frequency vibrations of the OH group and this quenching is eliminated when they are extracted into the organic solvent. In addition, the measured luminescence intensity can be further enhanced up to 17 times by performing the measurement at the excitation wavelength where the Ianthanide ions were not excited directly but indirectly through the energy transfer from the counterion (i.e., benzoate). The total enhancement by the extraction and energy transfer processes can, therefore, be up to 67 times. The mechanism of energy transfer and the use of this technique to measure the selective extractions of Tb 3 +, Eu 3 +, and Dy 3 + ions are discussed. - Anal. Chem. 62, 835-840 (1990). Dept. Chem., Marquette Univ., Milwaukee, WI (USA)

Comparison of photoacoustic spectroscopy, conventional absorption spectroscopy, and potentiometry as probes of lanthanide speciation. R.A. Torres, C.E.A. Palmer, P.A. Baisden, R.E. Russo and R.J. Silva.

We measured the stability constants of praseodymium acetate and oxydiacetate complexes by laser-induced photoacoustic spectroscopy, conventional UV-visible absorption spectroscopy, and pH titration. For the spectroscopic studies, changes in the free Pr absorption peaks at 468 and 481 nm were monitored at varying ligand concentrations. The total Pr concentration was 1 x i0-4 M in solutions used for the photoacoustic studies and 0.02 M for conventional spectroscopy. For the pH titrations, we used solutions whose Pr concentrations varied from 5 x 10 .3 to 5 x 10 2 M, with total ligand-to-metal ratios ranging from 1 to 10. A comparison of the results obtained by the three techniques demonstrates that photoacoustic spectroscopy can give the same information about metal-ligand speciation as more conventional methods. It is particularly suited to those situations where the other techniques are insensitive because of limited metal concentrations. - Anal. Chem. 62, 298-303 (1990). Lawr. Livermore Nat. Lab., Livermore, CA (USA)

Zur schnellen coulometrischen Bestimmung yon Europium. M. Hahn, H.H. Rfittinger, H. Matschiner und U. Spohn.

Eine schnelle coulometrische Bestimmung yon Eu aus SE-Gemischen oder ffir die Nebeneinanderbestimmung yon Eu(II) und Eu(III) bei der pr/~parativen elektrolytischen Eu(II)-Erzeugung aus Eu(III) wird beschrieben. Die Analyse erfolgt in einer coulometrischen Titrationszelle (frfiher beschrieben), wobei Cu(II) als Redoxmediator dient und das entstandene Cu(I) bromometrisch mit biamperometrischer Endpunkfin- dikation gemessen wird. Cu(II) reagiert st6chiometrisch mit Eu(II). Der Megplatzaufbau ist dargestellt. In der Megzelle wird eine 5 mm lange Pt-Zwillingselektrode ( ~ = 0,5 ram) mit 200 mV polarisiert. Die Pro- benltsung (59,52 _+ 0,03 pl) kann fiber ein Dosierventil direkt oder nach Durchleiten fiber eine Zn-Amalgam-Reduktorsfiule der Mel3zelle zugefiihrt werden. Die Reduktorsfiule besteht aus einem 25 cm langen Glasrohr (4 mm i.D.), das am unteren Ende zu einer CapilIare (0,8- 1,0 mm i.D.) ausgezogen und mit zu 20% amalgamiertem Zn-Griel3 (Siebfraktion 0,4-0,6 mm) gefiillt ist. Der Grundelektrolyt enthfilt 0,1 M KBr, 0,01 M HC1 und 0,05 M CuClz, der Gegenelektrolyt 0,25 M KBr, 0,01 M HCI. Staudardl6sungen werden aus hochreinem, bei 800- 1000 °C gegl/ihten Eu203 durch L6sen in 0,2 M HC1 unter Erw/irmen hergestellt, mit NaOH aufpH 2 - 5 gebracht. Vergleichende Bestimmun- gen mit ICP-AES zeigten gute Ubereinstimmung. Bis zu 60 Titrationen k6nnen in einer 10,6 ml-Elektrolytfiillung im Bereich 0,5-10 mg/l Eu in salzsaurer Probenl6sung in 20-120 s durchgeffihrt werden, eine Re- duktorfiiliung reicht f/Jr mehr als 1000 Analysen. Der Eu(III)-Gehalt ergibt sich aus der Differenz zwischen Eu-Gesamtgehalt und Eu(I1)- Gehalt durch direkte Titration bzw. nach Passieren des Reduktors. - Z. Chem. 29, 12, 453 -454 (1989). Marthin-Luther-Univ., Halle-Witten- berg, Sekt. Chem., Halle (DDR) A.M. Roscovanu

Solvent extraction separation of thorium as picrate complex with 18- crown-6. N.V. Deorkar and S.M. Kbopkar.

Thorium was quantitatively extracted from 0.04 M picric acid with 0.065 M of 18-crown-6 at pH 2.0-3.5. It was stripped from organic


phase with 0.5 M nitric acid and was determined spectrophotometrically at 655 nm as its Arsenazo-III complex. Thorium was separated from mixture containing cerium, uranium, zirconium, hafnium, yttrium and lead in complex mixtures. The method was extended for the analysis of thorium in monazite. - J. Radioanai. Nucl. Chem., Art. 134, 437-443 (1989). Dept. Chem. Indian Inst. Technol., Bombay (IND)

Immobilized arsenazo I as a sensitive element of optical sensor for uranium(VI). O.P. Shvoeva, L.M. Trutneva and S.B. Savvin.

Aufgrund der Immobilisierung yon Arsenazo I (ARS) in geeignetes Fasermaterial wurde ein empfindlicher optischer Fiihler zur U(VI)-Be- stimmung hergestellt. Als Material des festen Tr/igers verwendete man mit feindispersem Anionenaustauscher gefiillte Polyacrylfasern. Der Tr/iger wurde in Form einer Scheibe (Durchmesser 2 cm) verwendet. Die noch feuchten Scheiben (Gewicht 40-50 rag) wurden mit 50 ml 0,1 M HC1 und danach mit 10 ml Aceton nachgewaschen, fiir 5 min in 10 ml 2 × 10 -5 mol/1 ARS-L6sung eingetaucht, danach mit 50 ml 0,1 M HC1 und zum Schlul3 mit Wasser nachgewaschen und feucht aufbewahrt. Ihr ARS-Gehalt wurde spektralphotometrisch ()~m~ = 500 nm) bestimmt. Die Scheiben mit immobiliziertem ARS k6nnen zur Bestimmung yon U(VI) eingesetzt werden, wobei das analytische Signal bei 640 nm durch Reflexions-Spektralphotometrie gemessen wurde. Die Nachweisgrenze liegt bei 3 × 10 .8 tool/1 U(VI) unter 10 min. Filtrieren der Probel6sung durch die Sfiule mit dem immobilisiertem ARS. Auf diese Weise kann U(VI) auch in Gegenwart yon La(III), In, Zr, Ti(IV), Fe(II,III) und A1 bestimmt werden. Die Selektivitfitskoeffizienten der genannten Metalle sind in einer Tabelle zusammengefal3t. - Zh. Anal. Khim. 44, 2084- 2087 (1989) (Russisch, mit engl. Zus.fass.). F. Jancik

Determination of picogram quantities of americium und curium by thermal ionization mass spectrometry (TIMS). D. Poupard and B. Jouniaux.

Picogram quantities of curium and americium have been measured in solutions of natural elements and fission products by thermal ionization mass spectrometry using the resin bead method combined with isotopic dilution. The fixation yields of americium on a resin bead vary from 6%, when the element is extracted from a few ml solution, to 2% for an aliquot 15 times larger. For curium the yields vary from 6%, when it is extracted from a few ml of solution, to 1% for an aliquot 5 times larger. The ionization yields with CAMECA THN 206 spectrometers are 1 ion for 3000 to 5000 atoms for the resin bead method and 1 ion for 25000 to 30000 atoms in the case of direct loading on a triple ~lament. The reliability is determined by comparison of the mass spectrometric results with those obtained by alpha spectrometry. The relative standard deviation on Cm and Am ratios measurements is _+0.2%. - Radiochim. Acta 49, 25-28 (1990). CEA Radiochim. Phenomenol., Bruyeres-le- Chatel (F)

lower acidity than that with individual extractants. The species formed is tentatively assigned to be QzZrC16' TBP, where Q = R31~(CH3) for Aliquat 336 und R3NH for Alamine 336. - J. Radioanal. Nucl. Chem., Art. 134, 259-264 (1989). Dept. Chem., Utkal Univ., Vani Vihar, Bhubaneswar (IND)

Extraction of zirconium(IV) and separation of 9Szr-gsNh from acidic thiocyanate media by LIX 54 and its mixtures with TBP. P.K. Mishra, V. Chakravortty, K.C. Dash, N.R. Das and S.N. Bhattacharyya.

Appreciable extraction of 9SZr-9~Nb by LIX 54 from aqueous HC1 alone is not observed in the concentration range from 0.1 to 2 M HC1. Presence of thiocyanate ions results in appreciable extraction of this pair from such acid medium. Synergism has been observed in the extraction of zirconium(IV) by mixtures of LIX 54 and TBP from thiocyanate media, whereas there has been no appreciable synergism in case of niobium(V) under identical conditions. Slope analyses indicate the species extracted by pure TBP to be disolvate whereas for extraction by the mixtures of LIX 54 & TBP it is found to be monosolvate with respect to TBP. The extraction of both the metal ions have been found to depend on the concentration of acid as well as that of thiocyanate ions. Extraction increases with increase in percentage of either of the extractants. Effective separation of these congeneric pairs has been achieved by suitable choice of above system. Extraction is independent of aq. zirconium concentration upto 0.01 M above which it decreases. - Radiochim. Acta 49, 45-48 (1990). Dept. Chem., Utkal Univ., Vani Vihar, Bhubaneswar (IND)

Stickstoffbestimmung nach Kjeldahl - heute. H. Fischer. Nach einem Uberblick fiber die geschichtliche Entwicklung der Stick-

stoffbestimmung nach Kjeldahl, welche auch heute noch zur Stickstoff- bestimmung in Lebensmitteln und Futtermitteln eingesetzt wird, werden moderne Ger/ite vorgestellt, bei denen innerhalb einer Stunde, mit einer Schnellaufschlul3-Einheit sogar innerhalb yon 20 min, gedruckte Ergeb- nisse vorliegen. Der Beschreibung moderner AufschluBapparaturen folgt die Vorstellung der heute gebrfiuchlichen Destillationseinheiten, die auch fiir andere Bestimmungen, bei denen Wasserdampf-Destillationen notwendig sind, wie beispielsweise der Bestimmung des Ammoniumstick- stoffs, der Nitratbestimmung mit der Devarda-Legierung, der Bestim- mung des Phenolindex und der Ermittlung flfichtiger organischer S/iuren, einsetzbar sind. Die Durchfiihrung der Analysen wird anhand von kon- kreten Beispielen demonstriert. Die Verfahren werden auch in der Was- ser- und Umweltanalytik eingesetzt. Die erhaltenen Ergebnisse sind gut reproduzierbar, diirfen aber nicht automatisch als Bewertung fiir den Gesamtproteingehalt herangezogen werden, weil alle stickstoffhaltigen Substanzen erfal3t werden. - GIT Fachz. Lab. 34, 618-622 (1990). Bfichi Lab.-Techn. GmbH, D-7320 G6ppingen R.H.S.

Trace determination of titanium by differential pulse polarography. N. Diwan and A.P. Joshi.

Ti(IV), in trace amounts (1 - 1 0 ppm, 0.1 - 1 ppm, l0 -100 ppb, 2 - 10 ppb), is determined by differential pulse polarography in an electrolyte containing EDTA (0.015 mol), KBrO3 (0.004 mol) buffered with 0.1 M CH3COONa/CH3COOH at pH 5.2. Gelatin (1 x 10-~%) is used as maximum suppressor. Other electrolytes like HC1, HNO3, HC104, HzSO4, H3PO4, acetic acid, malonic acid, 5-sulfosalicylic acid, tartaric acid and citric acid (>~0.05 M) can also be used. In the determination, Ni 2+ (50-times); As 3+, Bi 3+ (20-times); Pb z+, W 6÷ (10-times); Zn, Cd (5-times) and Cu 2÷, Cr 3÷ (2-times) can be tolerated. Co 2÷, Sb 3÷ and Sn 4÷ interfere. The method is applied to determine Ti in corn, barley and coal. - J. Indian Chem. Soc. 66, 839-840 (1989). Dept. Chem., Univ., Nagpur (IND) H.B. Singh

Extraction of zirconium(IV) from HCI solutions by mixtures of Aliquat- 336 and Alamine-336 with TBP. P.K. Mishra, V. Chakravortty, K.C. Dash, N.R. Das and S.N. Bhattacharyya.

Synergism has been observed in the extraction of zirconium(IV) by mixtures of Aliquat 336 or Alamine 336 with a neutral donor TBP from aq. HC1 solutions. Although the extractant dependency for Zr(IV) is found to be nearly second power with respect to TBP alone, monosolvate is found to be formed for extraction by its mixture with Aliquat 336 or Alamine 336. Quantitative extraction is observed with mixtures at a

Spectrophotometrie determination of nitrite in aqueous solution by the diazotization-coupling method with p-aminobcnzophenone-N-(1-naphthyl)ethylenediamine. A.A. A1-Hatim.

Geringe Nitritkonzentrationen k6nnen spektrometrisch durch Diazo- tierung mit p-Aminobenzophenon und nachfolgende Kupplung des re- sultierenden Diazoniumkations mit N(1-Naphthyl)ethylendiamin unter Bildung eines rotvioletten wasserl6slichen Azofarbstoffs mit einem Ab- sorptionsmaximum bei 555 nm bestimmt werden. Dazu werden die Pro- ben mit 1 -25 gg NOa- mit 0,3%iger p-Aminobenzophenonl6sung und 0,5% N-(l-Naphthyl)ethylendiamin-L6sung versetzt. Nach Auffiillen auf ein geeignetes Volumen wird die Absorption bei 555 nm gemessen. Das Verfahren eignet sich ffir Nitritbestimmungen yon 0,04 - 1,00 ppm NO2-, die Eichkurven sind in diesem Bereich linear und die Empfind- lichkeit liegt bei 7 x 104 1.mol 1 .cm-1 bzw. 6,5 x 10 .4 gg/cm 2. Cu(II), Fe(III) und Phosphat verursachen geringe St6rungen, beim Einsatz von Abwasser erhfilt man Fehler yon - 3 % . - Intern. J. Environ. Anal. Chem. 38, 617-622 (1990). Dept. Chem., Coll. Sci., Univ. Mosul (IRQ)

R.H.S.

Retention behavior of nitrate ion on high-performance ion chromatograph columns. L.G. Daignault, D. Rillema, R. Shaver, D. Jackman and J.W. Burke.

Es wird gezeigt, dag die Ionenchromatographie eine excellente Me- rhode ist zur qualitativen und quantitativen Bestimmung yon Nitrat-


Ionen im ppt-Bereich bei kleinen Volumina, ohne dab eine Voranreiche- rung n6tig ist. - J. High Resolut. Chromatogr. 12, 476-478 (1989). Dept. Chem., Univ., Charlotte, NC (USA) M. Rittich

Indirect determination of arsenic by flotation spectrophotometry. S. Kunze, U. Dietze and G. Ackermann.

An indirect method of arsenic determination in the submicrogram range via the determination of molybdenum is presented here. High sensitivity is achieved by combination of the chemical amplification during formation of dodecamolybdoarsenic acid (arsenic:molybdenum ratio 1:12) with multiplication due to the formation of ion-association complexes during flotation-spectrophotometric molybdenum determination with crystal violet (molar ratio 1:2). Thus, the amplification factor relating to arsenic is 24. Dodecamolybdoarsenic acid is formed in a weakly acidic medium and is quantitatively extracted by n-butanol. Back extraction of the heteropoly acid to the aqueous phase and its simultaneous destruction provides the basis for the reaction of released molybdate ions with thiocyanate ions. The molybdenum-thiocyanate complex forms a sparingly soluble ion-association complex with crystal violet which can be floated with toluene on the phase boundary (film flotation). After separation of the aqueous phase the floated molybdenum compound is dissolved in acetone and the resulting free crystal violet ions are subjected to photometric determination at 590 nm as equivalent of the concentration of arsenic. The molar absorptivity of crystal violet is 3.2' I 0 s 1. tool- 1. cm - 1. Beer's law is obeyed in a concentration range from 0.01 to 1 gg Mo/ml (0.001-0.1 gg As/ml). The resulting detection limit for arsenic is 1 ng/ml. - Mikrochim. Acta 1989, III, 147 - 153. Res. Inst. Mineral Processing, Acad. Sci., Freiberg (DDR)

Voltammetric behaviour of arsenie(III) in presence of mercury(II) in nonaqueous media at a glassy carbon electrode. A.A. Ramadan, H. Mandil, P.K. Agasyan and A.I. Kamenev.

Man untersuchte das inversionsvoltammetrische Verhalten yon As(III) in Gegenwart von Hg(II) mit der Kohleglaselektrode (KGE) in 0,1 M LiC1Oa-L6sung in wasserfreiem Acetonitril (AN) (Wassergehalt max. 0,06 Vol.%). Gearbeitet wurde mit rotierender Scheiben-KGE (Fa Tacussel, F) und Ag/AgC1 als Bezugselektrode. Dazu werden 5 ml L6sung von 0,2 tool/1 LiC104 in der elektrolytischen Zelle mit n x 10-4 mol/1 Hg(lI)-L6sung in AN und mit den entsprechenden Mengen von As(III)-L6sung versetzt und mit AN auf 10 ml verdiinnt; die L6sung wird mit N2 15 - 20 min unter elektromagnetischem Rfihren durchgebla- sen. Die Elektroabscheidung von As in elementarer Form (As(III)-Kon- zentration /> 1 x 10 .4 mol/1 findet bei Er < -0 ,75 V, diejenige yon Hg bei 0 V statt. Die Inversionskurven werden bei der Potential/inderungsge- schwindigkeit von 10 mV/s aufgenommen. Bei der gleichzeitigen Elek- troabscheidung yon As und Hg werden zwei Peaks, bei 0,60-0,64 V und bei 2,00-2,08 V, gebildet. Der bei EE 3,0 V gebildete Peak wird der Entstehung von Hg3As2 zugeschrieben. Es wurde festgestellt, dab 1 x 10 - 7 - 1 x 10 -6 tool/1As(III) in Gegenwart von Hg(II) aufgrund des Peaks bei 2,05 V mit s~ = 0,016 bestimmt werden k6nnen. - Zh. Anal. Khim. 44, 2114-2117 (1989) (Russisch, mit engl. Zus.fass.). Haleb Univ., (SYR) F. Jancik

Application of the hollow cathode discharge emission source to the determination of nonmetals in microsamples. F.-Y. Chen and J.C. Williams.

The use of the hollow cathode discharge source for the excitation of nonmetals in volume-limited samples is discussed. The effect of break- down voltage, fill-gas composition, electrode composition, hollow size, sample deposition mode, current, and fill-gas pressure on the emission signal from phosphorus and chlorine are reported. Instrumentation, operation, and sample preparation procedures are described. Temporal profiles of the emission signal from very small samples deposited in the hollow are given for P, C1, and Se. Detection limits of 9 and 20 pg are reported for P and C1, respectively. - Anal. Chem. 62, 4 8 9 - 496 (1990). Dept. Chem., State Univ., Memphis, TN (USA)

Potenfiometric oxygen sensor using bismuth oxide yttrium oxide ion conductor. K. Nagashima, T. lshimatsu, T. Hobo and Y. Asano.

A low-temperature oxygen sensor was developed by using a bismuth oxide-yttrium oxide ion conductor which was prepared by sintering a mixture of Bi203 and Y203 (3:1 tool%) at 750°C for 10 h in air. The

sensor, which is expressed as Au/(Bi203)3Y2Oa/Au, is a small disk. Both the working and reference electrodes were made by sputtering gold in argon. The thickness of the sputtered gold layers and oxygen ion conductor were 30 nm and 0.3 ram, respectively. When the sample gas containing oxygen impinges at 10 ml rain-1 on the working electrode, the output of the sensor closely obeys the Nernst equation. The air in the cylinder was used as the reference gas. The detection limit for oxygen was about 0.05% in nitrogen. The response times of the sensors were 25 s and 10 s at 400°C and 500°C, respectively. The sensor did not respond to 10% carbon monoxide at 500°C. The life time of the sensor was at least 3 months under continuous operation at 400°C. - Bunseki Kagaku 39, 229-232 (1990) (Japanisch, mit engl. Zus.fass.). Fac. Technol., Metropol. Univ., Setagaya-ku, Tokyo (J)

Photometric and amperometric estimation of trace amounts of selenium and tellurium. S.C. Lavale and M. Dave.

Chromotropic acid is used for photometric and amperometric estimation of Se and Te. Amperometric titrations are done on a manual polarograph at - 1 .6 V vs SCE and -1 .25 V vs SCE for Se and Te respectively. In photometric method, the absorbance of the brown complex obtained in each case is measured at 470 nm within 1 h. The complex contains Se (or Te) and the ligand in 1 : 1 ratio. In determination of either Se or Te, 100-fold excess amounts of Li, Na, K, A1, CI-, Br-, I - and CHaCOO- do not interfere. - J. Indian Chem. Soc. 66, 914-915 (1989). Chem. Res. Labs., Govt. College, Betul (IND) H.B. Singh

Determination of chromium by ETA-AAS using different furnace materials. K. Pyrzyfiska.

Zur Bestimmung yon Chrom durch elektrothermische AAS werden eine Reihe von verschiedenen Graphitrohren getestet: ohne Uberzug, pyrolytisch/iberzogen sowie mit einem Wolfram- oder Zirkonium-Uber- zug. Desgleichen wird die Wirkung yon Minerals/iuren und der Einflul3 vieler begleitender Metallionen auf das Absorptionssignal des Chroms untersucht. Mehrere Mel3kurven sind abgebildet. Die Auswertung der Versuche zeigt, dab die besten Ergebnisse (Nachweisgrenze und RSD) mit pyrolytisch iiberzogenen Graphitrohren erzielt werden. - Anal. Lett. 22, 2847-2859 (1989). Dept. Chem., Univ., Warschau (PL)

W. Czysz

Adsorption studies of Cr(III) and Cr(VI) on lead sulfide, copper sulfide and zinc sulfide. Determination of Cr(III) in the presence of Cr(VI). M. Sarwar, M.K. Masood and S. Farooq.

Verff. untersuchen das Adsorptionsverhalten von gel6stem Cr(VI) in Gegenwart yon Cr(III) an Suspensionen von Blei-, Zink- und Kupfersul- rid. Sic stellen fest, dab Cr(VI) zu 100% an Bleisulfid bei pH 4,0 adsorbiert wird, w/ihrend dies fiir Cr(III) bei pH 7,0 der Fall ist. Die 100%ige Adsorption yon Cr(VI) findet an Zinksulfid bei pH 4,5 statt, die yon Cr(III) bei pH 6,5; an Kupfersulfid bei pH 5,0 (Cr(VI)) bzw. pH 7,0 (Cr(III)). Auf der Grundlage dieses unterschiedlichen Adsorptionsver- haltens erfolgt die getrennte Bestimmung von Cr(III) und Cr(VI) nach der Diphenylcarbazidmethode. Die Ergebnisse der Adsorptionsversu- che, Einflug der R/ihrzeit und der Temperatur der Adsorptionsl6sung sind in Tabellen aufgefiihrt. Messungen bekannter Mengen ergeben eine sehr gute Richtigkeit des Verfahrens. - Anal. Lett. 22, 2877-2885 (1989). Pakistan Council of Sci. & Industr. Res. (PCSIR) Labs. Complex, Lahore (PAK) W. Czysz

Spectrophotometric determination of molybdenum in rock, alloy steel, ore, ash and fertilizer by thiocyanate and N-octylbenzamidine. M, Das, K.S. Patel and R.K. Mishra.

Verff. priifen 11 Aminderivate yon Imidoylchloriden als Extraktions- mittel zur Entwicklung einer hochspezifischen spektralphotometrischen Bestimmung yon Mo(V) als 3wertiger SCN-Komplex und w/ihlen yon diesen N-Octyl-N'-phenylbenzamidin (OPBA) ffir weiterf/ihrende Un- tersuchungen aus. Arbeitsweise: Ein Aliquot mit 30 gg Mo(VI) in 150 ml Scheidetrichter abnehmen; 3 ml 10%ige Ascorbins/iurel6sung; 7,5 m110 M HC1 oder H2SO4 und 2 m120%ige NH4SCN-L6sung zusetzen; gegebenenfalls zu 15 ml mit dest. H20 erg~inzen. 2 min mit 15 ml 0,1% benzolischer Amidinl6sung extrahieren; Extrakt in 25 ml Becherglas fiber 2 g Na2SO4, wasserfrei, trocknen uud dann bei 465 --470 nm gegen Reagentienblindwert vergleichen. Verff. ziehen das Arbeiten im HC1-


Medium vor; optimale Sfiurekonzentration 2 ,0 - 7,0 M. Eine Verlfinge- rung der Extraktionszeit bringt nichts, ein Anheben der Konz. auf 0,01 M OPBA bzw. 0,7 M NH4SCN verfindern die Komplexfarbe nicht. Die Extraktion ist im Temperaturbereich 15-45°C quantitativ; der Farb- komplex bei Raumtemperatur 40 +_ 2°C (Sommer) 1 h stabil. Nachweis- grenze der OPBA-Methode 0,01 gg Mo/ml; lineares Verh/iltnis Absorp- tion zu Mo-Gehalt zwischen 0,3 und 5,3 ppm Mo; relative Standardab- weichung bei 30 p-g Mo/15 ml + 1%. Nb(V) st6rt empfindlich, ist aber mit 2 ml NazC204 (5%, w/v) zu maskieren. Bei 30 gg Mo sind zu tolerieren (Fehler 2%): 250 mg Ni(II), Mn(II); 190 Pb(II); 170 Co(II); 150 Cd(II), AI(III), AsOz~.3- ; 140 Zn(II), PO43-, C2042-; 130 U(VI); 120 Zr(IV); 80 Hg(II); 65 W(VI); 40 Fe(III); 30 Sb(III); 20 Cu(II), V(V), Ta(V); 15 Bi(III); 2 Nb(V) in Gegenwart yon Oxalat; 1 Ti(IV); 400 I - ; 2 $2032-; 210 Tartrat. - Analusis 17, 536-539 (1989). Dept. Chem., Ravishankar Univ., Raipur, M.P. (IND) G. Preis

Fluorimetric stopped-flow determination of iodide. M. Toledano, M.C. Gutierrez, A. Gomez-Hens and D. Perez-Bendito.

Trace levels of iodide were determined by a stopped-flow method based on the catalytic effect of I - on the Ce(IV)-As(III) system and measurement of the formation rate of the fluorescent cation Ce(III). The calibration graph was linear over the range 2 - 80 ng/ml of I - , the slope was 7.6 x 10 -3 ml/ng rain, and the limit of detection was 09 ng/ml. The relative standard deviation was 1.79% at the 40 ng/ml level. Tolerance levels for foreign ions are reported; the most serious interferences were from citrate, tartrate and thiocyanate. The stopped-flow method was compared with its conventional kinetic counterpart. The calibration graph of the stopped-flow method had a wider linear range, and the sampling rate was higher, making this method the more suitable choice for routine analysis of I - . - Analusis 17, 514-518 (1989)~ Dept. Anal. Chem., Fac. Sci., Univ., Cordoba (E) C.K. Laird

Influence of the supporting electrolyte nature on the analytical signal in the determination of halide ions by stripping voltammetry with a silver indicator electrode. M.S. Zakharov, N.S. Raikova, I.V. Leiba and T.V. Tonkova.

Das inversions-voltammetrische Verhalten von Halogenidionen (CI-, Br- , I - ; Hal) bei Verwendung der Ag-Indicatorelektrode (Bezugselek- trode GKE) wurde in L6sungen von Ba(NO3)2, NH~NO3, Cd(NO3)z, NazB4OT, CH3COONa, Natriumcitrat (0,1 tool/l) sowie EDTA (0,01 mol/1) als Grundelektrolyten untersucht. In allen diesen Ffillen wurde die elektrolytische Hal-Ausscheidung (1 x 10-5 mol/1) innerhalb 2 rain auf der Ag-Indicatorelektrode in Form ihrer Ag-Hal durchgeffihrt. Die voltammetrischen Kurven wurden bei der Potential/inderungsgeschwin- digkeit von 0,02 V/s registriert. Die Nachweisgrenzen yon HaMonen h/ingen von den Stabilitfitskonstanten (s. Original) ihrer Komplexe mit den Kationen der verwendeten Grundelektrolyte sowie der Komplexe von Grundelektrolytanionen mit dem elektrolytisch ausgeschiedenen Ag indirekt proportional ab. - Zh. Anal. Khim. 44, 2117-2119 (1989) (Russisch, mit engl. Zus.fass.). Univ. Tyumen (SU) F. Jancik

Influence of chemical modification of bromide-selective electrodes on their analytical characteristics. L.N. Moskvin, D.V. Golikov and V.V. Nikonorov.

Durch chemische Modifizierung von Br--ionenselektiven Elektroden (Br--ISE) mit Oxidationsmitteln, insbesondere mit H202, wird ihre Empfindlichkeit wesentlich erh6ht, so dab die Nachweisgrenzen n x 10- 6 _ n x 10 7 tool/1 Br erreichen. Die optimale Modifizierung yon Br--ISE auf der Basis yon AgBr wird mit 3%iger HzOz-L6sung bei pH 2 innerhalb 3 - 1 0 min durchgefiihrt. Auf diese Weise modifizierte man Br--ISE mit AgBr/Ag2S/AszS3-, AgBr/AgzS- und AgBr-Membra- nen, die nach der Modifizierung zugleich stabile Elektrodenfunktionen aufweisen. - Zh. Anal. Khim. 44, 2070-2073 (1989) (Russisch, mit engl. Zus.fass.). Univ., Leningrad (SU) F. Jancik

Speetrophotometric determination of iodine and iodide in non-aqueous solvents and study of formation of iodine-iodide complexes. A.A. Ramadan and S. Ashour.

Man untersuchte die M6glichkeit der spektralphotometrischen Titra- tion yon I2 und I - in organischen L6sungsmitteln (OL), wie Acetonitril (AN), Dimethylformamid (DMF) und Dimethylsulfoxid (DMSO), aufgrund der I-/I2-Komplexbildung nach den Reaktionen: I - + I2 ~,~ I3- bzw. I3- + I2 ~- I5 -. Bei der Titration yon 2,5 x 10-6 mol/112-L6sungen in DMSO und AN mit I--L6sung wird alles Iz in dem Komplex I3- gebunden, w/ihrend in DMF unter gleichen Bedingungen nur 1,25 x 10- 6 tool/1 I2 in dem Komplex I5 - gebunden werden. Auf diese Weise wurden die Konstanten der Komplexbildung (log K) yon I3- bzw. I5 - bestimmt. log K der I3--Komplexe liegen bei 7,56 (AN), 7,7 (DMF) und 6,1 (DMSO); log K I5- liegt bei 6,37 (DMF). Man bestimmte auch die e- Werte yon I2, I - , Ia- und I5- bei den entsprechenden )~max-Werten in den genannten OL (Tabelle). Spektralphotometrische Titration yon I2 bzw. I - : 25 ml Vergleichsl6sung yon Ia bzw. I - werden in einer dunklen Kiivette (0,1 ; 1,0; 5 cm-Schichtdicke) mit 10 - 4 0 gbPortionen des Titra- tionsmittels versetzt und die Extinktion wird gegen reines OL nach jedem Zusatz von Titrationsmittel gemessen. Der )kquivalenzpunkt wird wie iiblich bestimmt. - Zh. Anal. Khim. 44, 2016 - 2022 (1989). (Russisch, mit engl. Zus.fass.). Aleppo Univ. (SYR) F. Jancik

Kinetic spectrophotometric determination of manganese by use of the salicylaldehyde-hydrogen peroxide system. F. Salinas, J.J. Berzas Nevado and C. Guiberteau.

Zur Bestimmung yon Spuren Mn(II) wird ein kinetisches Verfahren beschrieben. Es basiert aufder katalytischen Wirkung yon Mn(II) auf die Oxidation yon Salicylatdehyd durch Hydrogenperoxid. Diese Reaktion wird spektralphotometrisch verfolgt; und zwar miBt man die Anderungs- geschwindigkeit der Extinktion bei 500 nm. Die Eichkurve ist linear im Bereich 5 - 1 0 0 ng Mn(II)/ml mit einem rel. Fehler yon _+ 1,2%. Das Verfahren eignet sich zur Mn(II)-Bestimmung in nat/irlichen Wfissern. - Anal. Lett. 22, 2803-2812 (1989). Dept. Anal. Chem., Univ. Extrema- dura, Badajoz; Dept. Chem. Univ. Castilla-La Mancha, Ciudad Real (E) W. Czysz

Separation of rhenium from silicon by electrodialysis. O.D. Prasolova, L.V. Borisova and A.N. Ermakov.

Es wird die Trennung von Rh und Si durch die Elektrodialyse beschrieben. Die fast quantitative Rh-Trennung von Si wird auf diese Weise in einer aus drei 50 ml-Kammern zusammengesetzten Zelle erreicht; die einzelnen Kammern sind durch eine Kationenaustauschmembran MKK-1 und zwei Anionenaustauschmembranen MAK-1 voneinander getrennt; die verwendeten Membranen weisen eine groBe Trennungsse- lektivit/it sowie eine hohe mechanische Festigkeit auf. Als Anode dient eine platinierte Titanscheibe, als Kathode eine Pyrographitscheibe, auf die die Potentialdifferenz yon 600 V aufgelegt wird; in dem Elektrodialy- sator wird 20 mA-Gleichstrom eingeschaltet. Die Elektrodialyse wird beendet, sobald man in dem Elektrodiatysator keinen Strom feststellt. Unter den beschriebenen Bedingungen wandert Rh zur Anode, w/ihrend Si, insbesondere bei erniedrigter Temperatur (Kfihlung mit Wasserlei- tungswasser), im Katholyt zurfickgehalten wird. Die optimale Rh/Si- Trennung verl/iuft bei pH 5,5-6,0. Nach der Abtrennung wird Rh in Form des Komplexes mit Thioharnstoff und Si in Form der blauen Molybd/inkieselheteropolys/iure spektralphotometrisch bestimmt. Das Verfahren kann zur Rh-Bestimmung in komplizierten L6sungen des Bleierzeugungsabfalls eingesetzt werden. - Zh. Anal. Khim. 44, 1998- 2001 (1989) (Russisch, mit engl. Zus.fass.). Vernadskii Inst. Geochem. Anal. Chem., Akad. Wiss., Moskau (SU) F. Jancik

Utilization of arsenic-containing ion exchangers for extraction and photometric determination of microgram amounts of rhenium. N.M. Kuznetsova, R.V. Strel'nikova, S.V. Bogushevskaya, N.G. Monakhova, A.B. Kozlova and E.K. Ryabova.

Die zur Bestimmung von Re-Mikrogrammengen (5 x 10 -3 mg/1) in technologischen L6sungen und festen Materialien ausgearbeitete Me- thode beruht auf der Re-Sorption aus schwefelsaurer L6sung auf arsen- haltigen Ionenaustauschern ARS-1A bzw. ARSO, die Arson- bzw. Ar- sinoxid-Funktionsgruppen enthalten, auf der nachfolgenden Re-De- sorption mit HC104 und seiner photometrischen Bestimmung in Form des Rhodanidkomplexes (Lmax = 430 rim). Auf diese Weise, unter An- wendung des Ionenaustauschers ARS-1A, bestimmte man Re in einer L6sung, die Se (20 mg/1), U (3 g/l), Mo (300 mg/1), NO3-, SO41- und weitere Komponenten (40-60 g/l) neben 0,3 bis 270 mg/1 Re enth/ilt (st = 0,07-0,02), sowie in festen 0,7 bis 3 x 10 .4 % Re enthaltende Materialien (Sr = 0,05--0,1). ZU diesem Zweck werden 5 - 5 0 0 ml mit H 2 S O 4 anges/iuerte (2 mol/1 HzSO,) Probenl6sung durch die ARS-IA-


S/iule (6 × 200 mm; Ionenaustauschermenge 4 -4 ,5 ml; Korngr6Be 0,4 - 0;6 ram) filtriert; Durchflul3 1 - 2 ml/min. Die Sfiule wird mit 80-100 ml 2 M H2SO4 und 50 ml Wasser gewaschen, Re mit 25 ml 1 M HCIO4 eluiert und im Eluat in Form von Rhodanidkomplex photometrisch bestimmt. Bei der Analyse yon festen Proben werden diese durch Aus- schmelzen mit MgO + KMnO4 bei 640°C und Auslagen der Schmelze mit Wasser gel6st, und Re wird in der L6sung wie oben beschrieben bestimmt. Die ermittelten Resultate der Re-Bestimmung in L6sungen sowie in festen Proben sind in Tabellen zusammengefal3t. - Zh. Anal. Khim. 44, 2007 ~2011 (1989) (Russisch, mit engl. Zus.fass.).

F. Jancik

Spectrophotometric determination of iron(II) and copper(II) with 2,6- pyridinediol. S.K. Bansal, S. Tikku, S. Shrey and R.S. Sindhu.

2,6-Pyridinediol is used for spectrophotometry of Fe(II) and Cu(II) at pH 7.0 - 10.2 and 7.5 - 10.8 respectively. Iron complex is formed when the reactants are heated on a water bath for 30 min. It shows Lm~x at 420 nm (e 1.08 x 104) and obeys Beer's law up to 4.8 ppm of iron concentration. Copper complex is formed on mixing the reactants (without heating), shows )~max at 535 nm (a 1.42 x 10 *) and obeys Beer's law up to 6.6 ppm of Cu concentration. Both the complexes contain metal and the ligand in 1:2 ratio. In determination of 3.5 ppm of Fe 2 + or Cu 2 +, the following ions (in ppm) do not interfere: Br 0500); C1- (1000); Hg 2+ (500); Mn 2+ (200); F - , Co 2+, Ni 2+ (100); Zn (50) and EDTA (5). NO3- (500), $2032- (20) and Cu 2+ (1.5) do not interfere in iron determination while NO3- (1000), $2032- (10) and Fe 2+ (100) can be tolerated in Cu determination. The method is used to determine the two metals in their alloys. - J. Indian Chem. Soc. 66, 917-918 (1989). Chem. Dept., Regional College Educ., Ajmer (IND) H.B. Singh

Determination of cobalt in water with a new reagent: Gamma-azo- nitrophenol. V.P. Dedkova, M.A. Azarashvili and S.B. Savvin.

Zur spektralphotometrischen Bestimmung von Co(II) im Trinkwasser wird ein neues Reagens, 5'-Nitrophenol-(2'-azo-1)-2-amino-8-naphthol- 6-sulfons/iure (Gamma-azo-nitrophenol, GANP) vorgeschlagen, das mit Co(lI) bei pH >/6 (Glycinphosphatpuffer) einen hellblau gef/irbten Komplex 0~max = 650 nm) bildet. Ein fQberschuB von Cu(II), Fe(III), Ni, Be, V(IV) und Ti st6rt; die genannten Metallionen k6nnen jedoch mit EDTA, F -, PO43 - und H202 maskiert werden. Als Maskierungsge- misch bew/ihrten sich 10%ige K4P2OT-, 0,1 M EDTA- u n d i M NaF- L6sungen, die im Verh/iltnis 1:1:1 gemischt werden. Das Verfahren erlaubt Co(II) im Trinkwasser mit einer Nachweisgrenze von 0,018 mg Co(II)/1 und einem Fehler von ~<3% zu bestimmen. Aufstellung der Eichkurve. In einem 25 ml-Mel3kolben werden 0; 0,5; 1,0 und 2,0 ml 1 × 10 -4 mol/1 Co(II)-L6sung mitje 5 ml Glycinphosphatpuffer (pH 6), 0,05 ml 0,1%iger w/igriger GANP-L6sung und nach 5 min mit 0,3 ml Maskierungsgemisch, mit Wasser und 0,5 ml konz. HC1 versetzt und mit Wasser zur Marke erg/inzt. Die Extinktion wird in einer 1 cm-Ktivette bei 645 nm gegen Wasser gemessen. - Zh. Anal. Khim. 44, 2012 -2015 (1989) (Russisch, mit engl. Zus.fass.). Vernadskii Inst. Geochem. Anal. Chem., Akad. Wiss., Moskau (SU) F. Jancik

Ion chromatography of transition and heavy metals. Analysis of metal ions as 4-(pyridylazo)resocinol complexes. A.A. Artskova, V.I. Orlov, A.R. Timcrbaev and O.M. Petrukhin.

Das auf der Basis des Polystyroldivinylbenzol-Ionenaustauschers BA- 2 hergestellte sowjetische Sorbens CHIKS-1 wurde zur Trennung von l~bergangs- und Schwermetallen (Co, Cu, Fe, Ni, Zn) in Form ihrer Komplexe mit 4-(Pyridylazo)resorcin (PAR) mittels der Ionen-Chroma- tographie verwendet. Gearbeitet wurde mit dem F1/issigkeits-Chromato- graphen Tswet-306 mit spektralphotometrischem Detektor (500 nm) auf zwei hintereinander verbundenen, mit CHIKS-I geffillten S/iulen (6 x 200 mm); als mobile Phase benutzte man 0,04 tool/1 NazCO3-L6- sung (pH 12) in w/il3rigem Aceton bzw. 2-Propanoi (40 Vol.%). Die aufgrund der Abh/ingigkeit der PeakhShe yon der Konzentration des zu bestimmenden Metallions aufgestellten Eichkurven verlaufen linear mindestens im Bereich von zwei Ordnungen; die Nachweisgrenze liegt bei 1 x 10-6 _ 2 x 10-5 mol/1, die absoluten Nachweisgrenzen (in rig/ 100 ~tl) entsprechend 0,3 (Co), 1,2 (Cu), 5,0 (Fe), 1,0 (Ni) und 8,0 (Zn). Fiir die Trennungsselektivitgt der zu bestimmenden Elemente k6nnen die angegebenen Werte der relativen Retentionszeit von den Komplexen

der erw/ihnten Metalle mit PAR (t'R in min) ausgenutzt werden: 5,75 (Co), 7,53 (Cu), 11,0 (Zn), i2,72 (Fe), 19,25 (Ni); t'R PAR = 6,50 rain. Der Trennungsmechanismus der genannten Komplexe auf CHIKS-I verl/iuft gleichzeitig unter dem Einfiul3 der Adsorption und des Ionenaus- tauschs. Die Methode wurde zur Bestimmung der erwS.hnten MetaUe in galvanischen Abfall6sungen ausgenutzt. Zh. Anal. Khim. 44, 2060 - 2065 (1989) (Russisch, mit engl. Zus.fass.). Mendeleev Inst. Chem. Tech- noI., Moskau (SU) F. Jancik

lsonitrosothiocamphor as a spectrophotometric reagent for rhodium(III). T.K. Thokdar, P.K. Paria and S.K. Majumdar.

Rh(III) reacts with isonitrosothiocamphor on heating to form a red complex suitable for extractive speetrophotometry of the metal. The complex extracted in CHC13 shows )~max at 345 nm (with a broad band at 470 nm) and contains metal and the ligand in 1:3 ratio. In the estimation of 9.7 ppm Rh, the following ions (in ppm) do not interfere: NO3-, SO42 , PO43 , ascorbate, tartrate, citrate, Mg, A l, La 3 + (1000); Ba, Zn (900); Sr (850); Ca, As 3+ (800); Zr 4+ (700); Th 4+ (600); SCN , $2032- (500); Cd, U 6+ (400); F - , Br-, C2042 , Pb, Mn 2+ (300); and Cr 3+ (200). Ni 2+ (250) and Co 2+ (50) can be tolerated in presence of EDTA. -- Procedure. To an aliquot of Rh soln. (50 - 150 ~g) add 0.5 ml of the reagent (0.4%) in ethanol) and keep the pH between 2 - 4 . Dil. to ]0 ml and heat on a water bath for 10 rain. Cool and extract with 10 ml CHC13. Dry the organic layer over anhydrous Na2SO4 and measure its absorbance at 345 nm against a reagent blank. - J. Indian Chem. Soc. 66, 918-919 (i989). Dept. Chem., North Bengal Univ., Darjeeling (IND) H.B. Singh

Column preconcentration of palladium using phenanthrenequinone dioxime supported naphthalene by atomic absorption spectroscopy. B.K. Puri, M. Satake, J. Miura and S. Usami.

Zur Anreicherung von Palladium aus w/il3riger LSsung verwendet man eine 60 mm x 5 mm i.D. Glass/iule, die unten mit einem Wattepropf abgedichtet ist und mit einem angeschl~mmten Chelatbildner, Phenan- threnchinondioxim (PQDO) auf Naphthalin in einer 0 ,5 - 0,7 cm hohen Schicht gefiillt wird. Beim Passieren der S/iule bildet Pd bei pH 1 ,2- 2,7 mit PQDO einen Komplex, der anschliegend mit 5 ml Dimethyl- formamid/Salpeters/iure (i00:4) herausgelSst wird. Das Effluat wird in die Acetylen/Luft-Flamme (0,6 und 2,1 kg/cm 2) gesprfiht, das Pd atomisiert und bei 244,7 nm gemessen. Die Eichkurve ist linear im Bereich 1 bis etwa 24 pg Pd in 5 ml der eingespriihten L6sung. Empfind- lichkeit ffir 1% Absorption: 0,126 pg/mI (0,153 pg/ml fiir die direkte AAS-Bestimmung in w/igrigem Medium). Verschiedene Anwendung- sm6glichkeiten (z. B. Umweltproben) werden angegeben. - Anal. Lett. 22, 2835 -2846 (1989). Dept. Chem., Texas A&M Univ., College Station, TX (USA); Fac. Engin. Univ., Fukui 910 (J) W. Czysz

Sensitivity enhancement for reciprocal derivative constant-current stripping determination of palladium in the presence of tin(II) during stripping. X. Ruan and H. Chang.

The reciprocal derivative constant-current stripping signal of palladium at a mercury film electrode is increased, as in anodic stripping voltammetry (ASV), by a factor of ca. 80 if a certain amount of tin(II) is present in the stripping solution. This catalytic stripping phenomenon has been successfully used as a means of sensitivity enhancement in constant-current stripping determination of trace palladium. The limit of detection is 4 x 10 - 10 M at S/N = 3, which is about two decades lower than that obtained without tin(II) present. Linear response was observed over the range 10 1 ° 10-7 M. This method has been applied to determine palladium in waste water and mineral samples. The experimental results support the postulated mechanism of signal enhancement, namely a ~chemical redeposition reaction occurring during the stripping, giving a cycle of stripping and deposition and thus increasing the stripping signal. - Talanta 36, 1081 - 1086 (1989). Dept. Chem,, Xiangtan Univ., Hunan (RC); Dept. Chem., State Univ., Ames, IA (USA)

X-Ray fluorescence determination of trace noble metals after concentration on POLYORGS XI-H as complexing sorbent. A.V. Dement'ev, I.I. Antokol'skaya, G.V. Myasoedova and N.M. Kuz'min.

Die zur Bestimmung von Spurenmengen yon Edelmetallen (EM; Pd, Rh, Ru, Ag, Ir, Au, Pt) vorgeschlagene Methode beruht auf der Anrei-


cherung auf dem feindispersen Fasersorbens POLYORGS XI-H, das auf der Basis von Benzimidazol vorbereitet wurde (cf. G. V. Myasoedova et aI.: Zh. Anal. Khim. 41, 1816 (1986)), und nachfolgender Bestimmung mittels R6ntgenfluorescenzanalyse (RFA). Das Sorptionsmittel mit den adsorbierten EM.wird 30 min bei 105°C getrocknet, sein Gewicht mit trockenem, keine EM enthaltendem Sorbens auf 1,5 g eingestellt, 6 - 7 rain in einer Vibrationsmtihle gemahlen und unter 300 MPa-Druck zu einer Tablette (Durchmesser 40 mm, Dicke 2 ram) geprel3t. Zur Bestim- mung von EM benutzte man das R6ntgenspektrometer Phillips PW- 1400 mit W-Anode (60 kV, 50 mA), F-Kollimator und Kristallanalysator LiF 200. Die Einstellungsparameter des spektrometrischen Kanals fiir alle EM sind in einer Tabelle angegeben; die Methode zeichnet sich durch hohe Genauigkeit aus. Man stellte fest, dab der durch gegenseitige Beeinflussung der zu bestimmenden EM bei einem Gehalt yon 7-300 gg/g bewirkte Bestimmungsfehler vernachl/issigbar ist. - Zh. Anal. Khim. 44, 2002- 2006 (1989) (Russisch, mit engl. Zus.fass.). Vernadskii Inst. Geochem. Anal. Chem., Akad. Wiss., Moskau (SU) F. Jancik

1.3 Organic analysis

Spectrophotometric method for microdetermination of nitrogen in Kjeldahl digest. M.B. Devani, C.J. Shishoo, S.A. Shah and B.N. Suhagia.

The method is based on the reaction of ammonia with acetylacetone- formaldehyde reagent in aqueous medium to yield yellow 3,5-diacetyl- 1,4-dihydrolutidine with a characteristic absorption maxima at 412 nm. The effect of several experimental variables on the determination of nitrogen was studied. The method was suitable for determination of nitrogen in acidic medium without interference from the usual catalysts employed for the digestion in Kjeldahl method. Lambert-Beer's law is obeyed in the concentration range of 0.5-6.0 pg nitrogen/ml in the reaction mixture. The molar absorptivity in terms of nitrogen was 1.4 x 103 1/mol cm. The standard deviation and relative standard deviation were +0.0447 and -+0.896% (n= 10), respectively. The method is simple, rapid, and precise. A variety of carbocyclic and heterocyclic nitrogen compounds have been analyzed for nitrogen content. The results are comparable with those obtained by AOAC method, 47.021. - J. Assoc. Off. Anal. Chem. 72, 953-956 (1989). L.M. College Pharm., Dept. Pharm. Chem., Navrangpura, Ahmedabad (IND)

Ion chromatography/mass spectrometry for the determination of organic ammonium and sulfate compounds. J.J. Conboy, J.D. Henion, M.W. Martin and J.A. Zweigenbaum.

The ion spray LC/MS interface is coupled via a postsuppressor split with an ion chromatography (IC) system. The micromembrane suppressor selectively removes over 99.9% of the ion-pair agents required for ion chromatography from the eluent. The resulting solution consists of analyte, organic modifier, and water, which is compatible with ion evaporation mass spectrometry. A flow rate of 0.8 or 1.0 ml/min from the column was split after suppression such that approximately 10-20 gl/min was direct to the ion spray LC/MS interface, which was coupled to an atmospheric pressure ionization (API) mass spectrometer. This system provided a convenient way to effect isocratic and gradient separations of organic ions under chromatographic conditions incompatible with most forms of mass spectrometric ionization. This work describes the separation and positive ion detection of quaternary ammonium drugs and tetraalkylammonium compounds of industrial importance using both single and tandem mass spectrometric detection (e.g., IC/MS and IC/MS/MS). The former easily provided the molecular weights of these compounds while the latter gave some structural information. The limit of detection of 40 pg injected on-colunm for tetrapropylammonium cation is a factor of 10 better than that obtained with the conventional IC conductivity detector. The separation, detection, and identification of some alkyl sulfates and sulfonates are also shown with negative ion detection. Again, IC/MS readily produced the molecular weights of these compounds while IC/MS/MS provided some-structural information. -

Anal. Chem. 62, 800-807 (1990). Drug Testing Toxicol., Cornell Univ., Ithaca, NY (USA)

Quantitative analysis of alkyl phosphates using automated cool on-column aqueous injection. J.J. Ellington and C.D. Trusty.

Es wird ein Verfahren zum Nachweis wasserl6slicher Alkylphosphate beschrieben. Dazu wurde eine M6glichkeit zur automatisierten on-column Probenaufgabe fiir die w/iBrigen L6sungen entwickelt. Eine regel- mfiBige Sptilung mit entsprechenden L6sungsmitteln verhindert die Ab- lagerung der Puffersalze. Wasserstoff- und LuftfluB k6nnen w/ihrend der Wasserelution aufrecht erhalten werden. - J. High Resolut. Chro- matogr. 12, 470-473 (1989). Environ. Res. Lab., U.S. Environ. Protect. Agency, Athens, GA (USA) M. Rittich

Polarographic determination of inorganic phosphorus in phytic acid. Lu Guanghan, Zhu Chuanfang, Wang Yu and Yao Shenglai.

Zur Bestimmung von anorganischem Phosphor in Phytins/iure wurde ein polarographisches Verfahren entwickelt. Dabei wurde zuerst der Mechanismus des polarographischen Verhaltens yon Mo/Sb/P untersucht, nachdem sie sich aufgrund fihnlicher Vorarbeiten anderer Autoren fiir eine L6ung yon Mo(VI)/Sb(III)/NaC1/Aceton als Tr/igerelektrolytl6- sung entschieden hatten. Bei Konzentrationen von 0,16 M HC1, 8 x 10 - 5 M Sb(III), 2 x 10 -3 M MoO42-, 8 x 10 -2 M NaC1 und 20% Aceton erreichte die Peakh6he fiir Phosphor ein Maximum bei proportionaler Beziehung yon P zur Peakh6he im Bereich 2 x 10 - s bis 2 x 10 - v g/ml P; Nachweisgrenze 8 x 10 -9 M. Eine genaue Arbeitsvorschrift fiir die P- Bestimmung in Phytinsfiure ist angegeben. - Anal. Lett. 22, 2531- 2540 (1989). Dept. Chem., Central China Normal Univ., Wuhan (RC)

W. Czysz

Optimization of the micro-scale determination of arsenates by direct potentiometric titration with silver ions and its application to the determination of arsenic in organic compounds. A. Pietrogrande and M. Zancato.

Zur Bestimmung von Orthoarsenaten in niedrigen Konzentrationsbe- reichen wird eine argentometrische Methode mit potentiometrischer Endpunktbestimmung entwickelt und optimiert. Die besten Ergebnisse erzielt man bei Titration in w/iBrig-methanolischem Medium, das auf pH 7,50 gepuffert ist. Mit dieser Ab/inderung der bisher fiblichen Titra- tionsweise minimiert man den Fehler, der durch geringffigige Mitf/illung yon Silberoxid in der Nfihe des Aquivalenzpunktes entsteht. Die in dem vorgeschlagenen Medium erhaltenen Werte weisen demgegen/iber gute Richtigkeit und Reproduzierbarkeit auf. Die Titrationen wurden ausge- fiihrt in einem Metrohm 636 Titroprozessor in Verbindung mit der automatischen Biirette 635 und einer Silberkombinations-Festelektrode EA 246 vom selben Hersteller. Titriert wurde mit 0,02 M Silbernitratl6- sung, die gegen Levamisolhydrochlorid standardisiert war. Das Verfah- ren wurde auf die Arsenbestimmung in organischen Verbindungen nach Sch6ninger-Verbrennung in einer Quarzspirale angewendet. - Anal. Lett. 22, 2521-2530 (1989). Dept. Pharm. Sci., Univ., Padua (I)

W. Czysz

Helium discharge detector for quantitation of volatile organohalogen compounds. D.A. Ryan, S.M. Argentine and G.W. Rice.

A helium discharge has been evaluated as an element-selective, GC detector for volatile organohalogen compounds. Absolute limits of detection ranged from 3 pg for chloroform to 29 pg for p-dibromobenzene with a linear response of 10 a - 104. The relative response of the detector was determined to be based solely on the mass of the halogen species present. This feature allowed for relatively simple quantitation of chlorinated and brominated haloform species in water samples by the addition of a single internal standard for calibration of the halogen response. - Anal. Chem. 62, 853 -857 (1990). Dept. Chem., College of William and Mary, Williamsburg, VA (USA)

Determination of tin in organotin compounds by electrothermal atomic absorption spectrometry. E.T. Kabeshova, A.B. Volynskii and A.N. Kashin.

Sn in zinnorganischen Verbindungen (ZOV) kann mittels der beschriebenen elektrothermischen AAS unter Verwendung des Graphitanalysa- tors mit der Plattform aus Pyrographit bzw. pyrokristallinischem Gra- phit bestimmt werden. Gearbeitet wurde mit dem AA-Spektrometer AA-

1.3 Organic analysis 667

30 (Varian) mit dem Graphitanalysator GTA-96, Deuteriumkorrektor des Untergrunds nnd automatischem Probendosierer. Das analytische Signal wurde mit Hohlkathodenlampe bei 300,9 nm gemessen. Bei der Sn-Atomisierung bewfihrte sich als Modifikator ein Zusatz von 0,2 pl 0,2%iger Pd(NO3)2-L6sung in 2 M HNO3 zu 10 pl Probe. Der katalyti- sche Effekt yon Pd(NO3)2 wird wahrscheinlich durch feindisperses me- tallisches Pd bewirkt. Zur Aufstellung der Eichkurve benutzte man (C6Hs)4Sn-L6sung in Tetrahydrofuran; die Eichkurve verlfiuft linear im Bereich yon 0 - 2 pg Sn/ml. Optimale Bedingungen der Sn-Bestimmung: Probentrocknung bei 75°C (10 s), Mineralisierung des Rfickstands bei 150 - 200°C (30 s), Atomisierung von Sn bei 2400 °C (5 s). Unter optimalen Bedingungen der Sn-Bestimmung in ZOV mit Siedepunkt fiber 108°C entspricht der systematische Bestimmungsfehler h6chstens 4%. Die ermittelten Resultate der Sn-Bestimmung in ZOV mit 10 -54% Sn sind in einer Tabelle zusammengefaf3t. - Zh. Anal. Khim. 44, 2023-2027 (1989) (Russisch, mit engl. Zus.fass.). Lomonosov Univ., Moskau (SU)

F. Jancik

Some observations on the rapid microdetermination of iodine in organic compounds. C.Y. Wang and Y.Q. Li.

A small-scale method for the microdetermination of iodine in organic compounds is described. An interfacial voltaic cell is used as the indicator in combination with the Sch6niger decomposition of sample. This method has the advantages of being simple, rapid, and economical and of having very sharp endpoints. The presence of nitrogen, fluorine, sulfur, phosphorus, boron, silicon, sodium, and potassium does not interfere with the microdetermination of organic iodine. The absolute error is _+0.2%. - Microchem. J. 40, 360-363 (1989). Dept. Chem., Yunnan Univ., Kumming, Yunnan (RC)

Fluorescence chiral derivatization reagents for high-performance liquid chromatographic resolution ofenantiomerlc hydroxyl compounds. J. Goto, N. Goto, G. Shao, M. Ito, A. Hongo, S. Nakamura and T. Nambara.

Zwei empfindliche und m/igig reaktive chirale Derivatisierungsreagen- tien gegenfiber enantiomeren Alkoholen mit einer Binaphthalingruppe als Fluorophor und Carbonylchlorid als reaktiver Gruppe werden entwickelt. Die Derivatisierungsreagentien ( - ) - und (+)-2-Methyl-l,l '-binaphthalin-21-carbonylcyanid werden aus Dimethyl-l,i '-binaphthalin- 2,2'-dicarboxylat in einem mehrstufigen Verfahren hergestellt. Zur Reak- tion dieser Reagentien mit enantiomeren Alkoholen wie beispielsweise [3-Hydroxysfiuren und I3-Blocker-Enantiomeren kann unter milden Re- aktionsbedingungen gearbeitet werden. Die Derivate k6nnen durch HPLC auf einer normal-phase Cosmosil 5Sl-Sfiule in Pentan/Ethylacetat oder auf einer Spherical Silicagel-S/iule in Hexan/Ethylacetat oder mit 0,3% Methanol in Hexan/Chloroform als mobiler Phase getrennt werden. Die Esterderivate k6nnen gut fluorimetrisch bei 342/420 nm nachgewiesen werden. Man erhfilt Nachweisgrenzen yon 200 pg. - Anal. Sci. 6, 261-264 (:1990). Pharm. Inst. 3-ohoku Univ., Aobayama, Sendai (J)

R.H.S.

Color change behavior of water soluble azo-dye ions in a water-organic solvent mixed medium and its application to a spectrophotometric method for the determination of ethanol. S. Motomizu, Y. Hosoi and M. Oshima.

Solvent effects on the absorption spectra of water soluble azo-dye ions were investigated. Three types of azo-dyes (Type I, II and III) were used: Type I consists of 4-(4-dialkylaminophenylazo)benzene sulfonate ions (alkyl: methyl, ethyl, propyl and butyl groups), Type II, of 1-alkyl-4-(4- diethylaminophenylazo) pyridinium ions (alkyl : methyl, ethyl and propyl grouPs ) and Type III, ofN, N,N-trimethyl-p-phenylazoanilinium ion and its nitro derivative. Of these three types, the Type I dyes showed the most remarkable change in absorption spectrum. The absorption maximum wavelength decreased with increasing alcohol content: the more hydrophilic the dye ion and the alcohol, the greater was the blue shift of the absorption spectrum. By measuring the change in Propyl Orange absorbance at 420 nm, ethanol can be determined. The absorptiometric method of ethanol determination with Propyl Orange was applied to the flow injection procedure. - Bunseki Kagaku 39, 201-205 (1990) (Japanisch, mit engl. Zus.fass.). Dept. Chem., Fac. Sci., Univ., Okayama (J)

A practical method for the determination of optical purity of secondary alcohols. S.-S. Wu, Y.-H. Wen, Y.-F. Wang and H.-L. Wu.

A practical method using commercially available N-carbobenzoxy-L- phenylalanine(N-CBZ-Phe) as a potential homochiral derivatizing reagent for the HPLC determination of the enantiomeric composition of chiral secondary alcohols has been developed. The procedure is simple and its application to the determination of the enantiomeric composition of several optical secondary alcohols proved to be satisfactory. - J. Liquid Chromatogr. 12, 2997-3005 (1989). Sch. Pharm., Kaohsiung Med. Coll., Kaohsiung, Taiwan (RC)

Capillary gas chromatography of amines with ammonia as carrier gas. M. Abdel-Rehim, M. Hassan and H. Ehrsson.

The use of ammonia as a carrier gas for the chromatography of aliphatic and aromatic amines has been investigated. As compared to nitrogen, ammonia gave drastically improved peak symmetry and lower capacity factors (k') for primary and secondary amines on polar (poly- ethylene glycol) and medium polar (methylphenylcyanopropylsilicone) stationary phases. The effect of ammonia was more pronounced at low column temperatures. Considerably better detection limits of primary and secondary amines were obtained with ammonia as carrier gas than with nitrogen. No detrimental effects of using ammonia were observed on the gas chromatograph or on the columns over a period of about one year. - J. High Resolut. Chromatogr. 13, 252-256 (1990). Dept. Anal. Pharm. Chem., Biomed. Centre, Univ., Uppsala (S)

Construction and characterization of a beet stem-based biosensor for oxalate. S.A. Glazier and G.A. Rechnitz.

Verff. beschreiben einen Biosensor zur Bestimmung von Oxalat. Grundlage ist die Inkorporierung von in einem M6rser pulverisiertem pflanzlichem Material (Stengel von roten Beeten (Beta vulgaris rapacea) nach Anschl/immen mit Mineral61 in Graphitpulver, das als elektroak- tive Grundlage einer amperometrischen Graphitpaste-Elektrode (Acryl- stab mit Messingkontakt) diente. Das bei der enzymatischen Zersetzung des Oxalats durch Oxalat-Oxidase entstehende H202 wird bei einer Arbeitsspannung von 0,900 V vs. GKE registriert. Alle Messungen werden in einem Bernsteins/iure/EDTA-Puffer bei pH 4,00 durchgeffihrt. Man erh/ilt reproduzierbare Responsen (innerhalb 1 rain) bei einer Nach- weisgrenze von < 1,03 × 10 .4 M. Die Elektrode war nach 15t/igigem Gebrauch noch voll aktiv. Glykolsfiure, Glucose, DL-Valin oder Pyruvat werden nur in sehr geringem Made angesprochen. - Anal. Lett. 22, 2929-2948 (1989). Hawaii Biosensor Lab., Dept. Chem., Univ. Hawaii at Manoa, Honolulu, HI (USA) W. Czysz

Improved enzyme electrode for amygdalin. A. Ciucu, V. Magearu and C. Luca.

Verff. beschreiben eine Enzymelektrode zur Bestimmung des Cyanhy- dringlucosids Amygdalin. Sic besteht aus einer Cyanid-selektiven Elek- trode, deren Oberfl/iche mit einer Dialysemembran fiberzogen wird. die kovalent immobilisierte ]3-Glucosidase enth/ilt. Dieser Sensor zeigt gegen/iber/ihnlichen, in der Literatur beschriebenen Sensoren verbes- serte Responseeigenschaflen. Der Linearit~itsbereich liegt bei ~[0 -1 10 .5 M Amygdalin. Die Ansprechzeit ist kfirzer und die Stabilit/it der Elektrode h6her als bei den bisher beschriebenen Sensoren. - Anal. Lett. 22, 2673-2683 (1989). Nat. Inst. Chem., Dept. Chem. Technol., Bukarest (R) W. Czysz

Quantitative determination of glucose, fructose, and sucrose, and separation of fructo-oligosaccharides by means of TLC. J. Gr6sz and W. Braunsteiner.

The TLC separation of reaction mixtures consisting of glucose, fructose, sucrose, and different fructo-oligosaccharides is described. The mobile phase mixture contains boric acid and is suitable for many problems within the framework of sugar analytical chemistry. The monosac- charides glucose and fructose are separated most efficiently. Quantifi- cation was undertaken after staining with thymol-sulfuric acid reagent and measurement of reflectance or, respectively, derivatization with zir- conyl chloride and measurement of fluorescence. The two methods are compared and two practical examples are shown. - J. Planar Chromatogr. 2, 420 423 (1989). ()sterr. Zuckerforschungsinst, Fuchenbigl (A)

Indirect detection of cyclodextrins in micro-HPLC. T. Takeuchi, M. Murayama and D. Ishii.


Da fiir die Micro-HPLC keine Refraktionsdetektoren erh/iltlich sind und gleichzeitig Cyclodextrine keine UV-Absorption zeigen, bleibt als Ausweg die indirekte Detektion in AnschluB an die Mikro-HPLC. Es stehen dabei zwei unterschiedliche Methoden daffir zur Verffigung. Zum einen kann Theobromin als Visualisierungsreagens verwendet werden. Dabei entsteht das Signal als Folge einer Pertubation. Zum anderen bilden verschiedene Cyclodextrine und Phenolphthalein EinschluBkom- plexe, die im Chromatogramm zu verschiedenen Zeiten auftauchen. - J. High Resolut. Chromatogr. 13, 6 9 - 7 0 (1990). Res. Center Resource Energy Conserv., Nagoya Univ., Chikusa-ku, Nagoya (J)M. Rittich

HPLC of benzene derivatives on Silasorb 600 dynamically modified by cetrimide. V.D. Shatz and O.V. Sahartova.

The sorption of cetrimide onto Silasorb 600 silica from mobile phases containing acetate buffer and acetonitrile has been studied. It has been shown that cetrimide forms a hydrophobic layer on the silica surface functioning as a nonpolar stationary phase in the separation of benzene derivatives. The surface density of cetyltrimethylammonium groups depends on mobile phase composition and can reach I gmol/m 2. An increase in acetonitrile concentration in the mobile phase causes a nonlinear decrease in the logk'-values, while the logarithms of partition coefficients between the mobile phase and immobilized cetrimide follow a linear relationship. Variation in pH and ionic strength leads to changes in the amount of the stationary phase in the system, this being largely responsible for variation of capacity factors for neutral and basic solutes. - J. Liquid Chromatogr. 12, 2801-2819 (1989). Inst. Org. Synth., Latvian SSR Acad. Sci., Riga (SU)

Some observations on the determination of phenol using ion selective electrodes. W.H. Chan, A.W.M. Lee and M.S. Wong.

A PVC phenoxyacetate selective electrode has been developed for the indirect sensing of phenol, after in situ derivatization with chloroacetic acid. The electrode exhibits a Nernst response in the range 10 - 1 - 3.2 x 10 4 M phenoxyacetate with a slope of 68.9 mV per concentration decade. The electrode has a wide working pH range (7.5-11.0), a fast response time (less than 1 min), and is stable for at least 1 1/2 months. - Microchem. J. 40, 322-327 (1989). Dept. Chem., Hong Kong Baptist Coil, Kowloon (HK)

Determination of 2-naphthol and its derivatives in the presence of each by HPLC. A. Vincze and M~ Leventiszn~ Huszfir.

W/ihrend bei der GC ein thermischer Zerfall zu beobachten ist, stellt die HPLC die Methode der Wahl zur Bestimmung yon 2-Naphthol und dessert Derivaten dar. Als S~ulenmaterial dient eine C 1 s-Sfiule, als Eluent ein Acetonitril-Wasser-Gemisch. Die Detektion erfolgt mittels UV-De- tektor. - J. Liquid Chromatogr. 12, 2887-2892 (1989). Res. Devel. Co. Org. Chem. Ind., Budapest (H) M. Rittich

Room-temperature luminescence of the volatile compounds, I- and 2-naphthol, and other compounds, 5,6-benzoquinoline, 4-phenylphenol, phen- anthrene, triphenylene, and p-aminobenzoic acid, adsorbed on filter paper treated with salts and cyclodextrins. S.M. Ramasamy and R.J. Hurtubise.

1- and 2-Naphthol are known to volatilize upon heating along with solvents such as ethanol and water. Filter paper, treated with salts and cyclodextrins, was shown to be capable of trapping these volatile phosphors efficiently on filter paper and permitting strong luminescence signals to be observed. Filter paper samples treated with and without cyclodextrins were compared on the basis of their ability to induce room- temperature fluorescence and phosphorescence from adsorbed naph- thols and five other organic compounds. Also, the effect of heavy atom salt, NaBr, on the phosphorescence intensities Qf phosphors adsorbed on the filter paper surfaces was studied. - Microchem. J. 40, 3 1 7 -3 2 1 (1989). Chem. Dept., Univ. Wyoming, Laramie, WY (USA)

Voltammetric determination of ~-naphthylamine. J. Hurek, K. Tupaj- Wiszniewska and K. Nowak.

Three methods of 13-naphthylamine determination were developed: direct polarographic determination in acetonitrile as well as two indirect procedures of determination in aqueous medium, as a formyl or diazo derivative. All proposed methods have a good precision and accuracy. In comparison with the most frequently used. ftuorimetric and

spectrophotometric methods the voltammetric ones are experimentally simpler and more sensitive in the range 10-3_ 10-5 mol 1-1 The out- standing is the procedure based on the diazo-derivative and pulse voltammetry with hanging mercury electrode. The adsorptive preconcentration ensures significantly better sensitivity in comparison to the other procedures. The measurement of the current is simple and a single, good shaped peak is observed, which height is linearly dependent on 13- naphthylamine concentration. The measured currents are stable in time in contrary to the absorbance in the order methods. - Chem. Analit. 34, 53 - 61 (1989) (Polnisch, mit engl. Zus.fass.). Inst. Chem., High Paed. School, Opole (PL)

Selectivity of 2-(1-pyrenyl)ethylsilylated silica gel in the isomer separation of cyclohexane derivatives. N. Tanaka, K. Hosoya, Y. Tachibana, M. Araki, K. Tanaka and A. Kaji.

Separations of trans and cis isomers of disubstituted cyclohexanes are studied by using 2-0-pyrenyl)ethylsilylated silica gel and octadecylsilylated silica gel in aqueous methanol mobile phases. The Cls phase gives better separations for 1,4-disubstituted compounds based on the differences in the hydrophobicities of the solutes, while the stationary phase containing pyrenyl groups gives better separations for 1,2-disubstituted cyclohexanes based on the recognition of the structural planarity and the orientation of the polar substituents. The complementary use of the two stationary phases seems to be useful in isomer separations by RP-LC. - J. Chromatogr. Sci. 27, 735-740 (1989). Kyoto Inst. Tech- nol., Dept. Polym. Sci. Engin., Matsugasaki, Sakyo-ku, Kyoto (J)

Identification of monoterpenes from their pyrochromatograms by pattern recognition. A. Cuculova and N. Dimov.

A post-column pyrolysis gas-chromatography of monoterpene hydrocarbons in vapour phase and diluted with the carrier gas is carried out. The pyrochromatograms obtained are sufficiently specific. The possibility to identify the pyrolysed monoterpenes based on their thermal fragmentation is shown. A chemometrical approach, based on pattern recognition, is proposed for identification when numerous compounds are presented in the samples. Using a classificator With pyrochromatograms of only 14 monoterpenes, their 100% identification between 61 peaks is achieved. - Izv. him., BAN 4, 533 - 541 (1988).

Comparing centrifugal countercurrent chromatography, nonaqueous reversed phase HPLC and Ag ion exchange HPLC for the separation and characterization of triterpene acetates. T. Abbott, R. Peterson, J. McAlpine, L. Tjarks and M. Bagby.

A triterpene acetate mixture was isolated from Asclepias linaria, Car., by solvent extraction and preparative HPLC. Three semipreparative chromatographic techniques were used to separate the mixture into individual components. HPLC on a silver ion exchange resin followed by separation on a reversed phase column gave good separations with a single pass on each column. Countercurrent chromatography gave less complete separation than either of the other two techniques but enriched some components to 78% in the collected fractions. - J. Liquid Chromatogr. 12, 2281.-2301 (1989). U.S'. Dept. Agric., Res. Serv., North. Reg. Res. Cent., Peoria, IL (USA)

Solid-state analysisof eumelanin biopolymers by electron spectroscopy for chemical analysis. M.B. Clark, Jr., J.A. Gardella, Jr., T.M. Schultz, D.G. Patil and L. Salvati, Jr.

The single most misleading aspect of structure elucidation of naturally occuring biopolymers lies in the removal and preparation of the sample for chemical and physical composition analysis. We present a method for the application of electron spectroscopy for chemical analysis (ESCA or XPS (X-ray photoelectron spectroscopy)) to elucidate the chemical composition and organic functional group distribution within one type of biopolymer, eumelanin. Qualitative and quantitative elemental analyses were calibrated with model compounds. In addition, the relative proportions of the different carbon, oxygen, and nitrogen functionalities within these eumelanin precursor model compounds and the polymers generated from them are presented. The ESCA results showed that eumelanin has structural and compositional components consisting of both aromatic and partially oxidized units of 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid. - Anal. Chem. 62, 949-956

2.1 Inorganic industrial products 669

(1990). Dept. Chem., Surface Sci. Center, State Univ., Buffalo, NY (USA)

Indirect determination of pyrrolizidine alkaloids by flame atomic absorption spectrometry. C. Nerin, J. Cacho and A. Garnica.

Zur indirekten Bestimmung der Pyrrolizidinalkaloide Nemorensin, Platyphyllin, Senecionin and Seneciphyllin mit Hilfe der Flammen-AAS werden die Alkaloide als lonenpaare mit BiI4-, die einen r6tlichorangen- farbenen Niederschlag in wfil3rig-saurer L6sung bilden, mit 1,2-Dichlor- ethan extrahiert. Bi wird in der organischen Phase nach Atomisieren in einer Luft/Acetylenflamme bei 223,1 nm bestimmt. Die experimentellen Bedingungen, pH, Konzentration von BiI4-, Schiittelzeit, Phasenver- hS.ltnis und Anzahl der Extraktionen sowie der Eichkurvenbereich werden bestimmt und optimiert. Der Linearbereich liegt zwischen 0,13 und 1,91 mg Alkaloid/ml; Standardabweichung 2 ,4 - 3,2%,je nach Alkaloid. Streptomycin, Vitamin B2, Ephedrin und Codein st6ren nicht; ebenfalls nicht Sulfonamide, die Vitamine der B-Gruppe, Antibiotica, Zucker, Tr/igerstoffe und Guajakolglycerylether (da keine dieser Verbindungen als Ionenpaar mit BiI4- extrahiert wird). - Anal. Lett. 22, 3041 - 3055 (1989). Dept. Quim. ETSIIZ, Zaragoza (E) W. Czysz

2 PARTICULAR PRODUCTS AND FIELDS OF APPLICATION

2.1 Inorganic industrial products

Trace matrix separations for high-purity chromium, molybdenum and tungsten with cellulose collectors. W. B16dorn, R. Krismer, H.M. Ortner, J. Stummeyer, P. Wilhartitz and G. Wiinsch.

Trace metals (20 elements) in high-purity chromium, molybdenum and tungsten are collected and preconcentrated by precipitation and adsorption on cellulose collectors. The compound methods allow the application of AAS and ICP-AES as determination methods for the production control of highly pure refractory metals under routine conditions. - Mikrochim. Acta 1989, IlI, 423-432. Inst. Anorg. Chem., Univ., Hannover (D); Metallwerk Plansee GmbH, Reutte/Tyrol (A)

Extraction inductively coupled plasma-optical emission spectrometry (ICP-OES) determination of traces of phosphorus in tungsten. G. Bauer, W. Wegscheider, K. Miiller and H.M. Ortner.

A method for the separation and preconcentration of traces of phosphorus from tungsten was developed. Solid phase extraction of the phosphovanadomolybdate complex performed on a micro-column was applied. Phosphorus was determined by optical emission spectroscopy (OES) with inductively coupled plasma (ICP) excitation. A limit of detection of 0.4 gg/g P with respect to the solid phase is obtained. By directly coupling the extraction/elution step to the ICP instrument a detection limit of 0.06 gg/g P in W was achieved. Besides, the complexity of spectral evaluation in ICP-OES determinations of traces in spec- tralline-rich matrices is discussed. - Mikrochim. Acta 1989, III, 399- 412. Inst. Anal. Chem., Micro- and Radiochem., Univ. Technol., Graz (A)

Sample introduction into ICP-OES for metallic samples. K.D. Ohls. Two different methods of sample introduction into an ICP source

have been applied to solve special problems of metal analysis. First, an electrolytical cell was used to dissolve the metallic compounds of metals only. The resulting analyte solution is flow-injected directly into the ICP. Secondly, the solid sampling by a graphite crucible heated up temperature-controlled and coupled directly to the ICP torch system was modified to determine 9 trace elements contained in 24 available certified reference samples. - Mikrochim. Acta 1989, III, 337-346. Hoesch StahI AG, Dortmund (D)

Determination of boron in boron-alloyed steels by inductively coupled plasma atomic emission spectrometry. I. Hlav~t~ek and I. Hlavfi6kovfi.

An inductively coupled plasma atomic emission spectrometry (ICP- AES) procedure has been developed and examined for the determination of boron content (0.0/up to about 2% B) in boron-alloyed steels such as POLDI ATA BOR (65% Fe, 19% Cr, 12% Ni, 1.5% Mn, 1% B), POLDI ATA BOR EXTRA (62% Fe, 18% Cr, 13% Ni, 2.5% Mo, 1.5% Mn, 1% B) and POLDI ATA BOR-R (75% Fe, 18% Cr, 3.5% Ti, 1.8% B). The steel sample is dissolved with a mixture of hydrochloric, nitric, sulfuric and phosphoric acids in a quartz vessel. Borides of alloyed metals, especially of iron and chromium, are quantitatively decomposed. The presence of phosphoric acid in a sample solution reduces the vola- tility of boric acid with water vapour. - Mikrochim. Acta 1989, IlI, 309--314. Chem. Labs. Poldi-United Steelworks, Kladno (CS)

Determination of titanium and aluminium in ferrotitanium by complexometric titration. A. Karolev.

The determination is based on the quantitative replacement of EDTA in TiOEDTA and A1EDTA by fluorine ions. The titration can be carried out either in the presence of all components or after separation of Ti and A1 as benzoates. The complexometric titration is carried out as follows: An excess of EDTA solution (0.05 tool/l) is added to an aliquot of the hot sample solution or to the dissolved benzoates of Ti and AI. The solution is neutralized first to pH = 0.5-1.0 with ammonia (i + 2) and then to pH = 5.5-5.8 with 20% hexamethylene tetramine solution, cooled to room temperature and the excess EDTA titrated with 0.025 tool/1 ZnC12 solution (indicator xylenol orange). Then the pH is again adjusted to 5.2-5.7 (indicator paper), the solution is cooled to below 10°C, ice pieces are added and finally 4% NaF solution with pH = 5.2 - 5.7. The solution is titrated immediately with 0.025 mol/1 ZnC12 solution to a colour change from yellow to orange-pink or pink which is stable within 1 5 - 20 sec. The consumed titrant is equivalent to Ti content. An additional amount of NaF solution is added, the solution is boiled for 2 - 3 rain cooled to room temperature and titrated with 0.025 tool/1 ZnC12 solution (additional xylenol orange is added as well). The consumed titrant is equivalent to the A1 content. The developed procedure is applied to the determination of titanium and aluminium in ferrotitanium alloys. - Metalurg. 1, 22-25 (1989).

Atomic absorption spectrophotometric determination of lead in aluminium alloys using direct atomization of solid in a pyrocoated graphite-cup atomizer. N.A.N. Awad and F. Jasim.

A direct solid electrothermal atomization atomic absorption (ETA- AAS) method has been developed for the determination of lead in aluminium alloys using standard reference aluminum alloys as solid and solution calibrants for lead. An acceptable agreement with lead certified values has been achieved. Typical results for lead in two certified aluminum alloys using solid calibrants are: precision varies over the range RSD% 5./0-6.45%. A comparison of the results obtained with those determined by solution standard additions has been made. Accuracy agrees within 3 % of the certified values. Limits of detection using 0.110 mg of standard alloy are 26.00 and 22.50 pg/g; and for 5 gl injected alloy standard solution, limits are 66.00 and 43.20 pg, respectively. Characteristic mass (sensitivity) equals 70.30 pg/0.0044 A s. Beer's law is followed in the range 0.0-25.0 ng. X-ray diffractometry has been employed for identifying lead species possibly deposited within the atomizer. The method has been applied to the determination of lead in aluminium foils, wires, cables, ingots, and bars. - Microchem. J. 40, 352--359 (1989). Dept. Chem., Coll. Sci., Univ. Baghdad, Jadriya, Baghdad (IRQ)

Extractive spectrophotometric method for the determination of iron in titanium base alloys using 4-(2-pyridylazo)resorcinol and a long chain quaternary ammonium salt. M.R.P. Reddy, P.V.S. Kumar, J.P. Shyamsundar and Y. Anjanyulu.

An anionic complex formed between iron(III) and 4-(2-pyridylazo)- resorcinol is quantitatively extracted with cetyldimethylbenzylammo- nium cation as red coloured iron-pair in chloroform at pH 6.0-7.5 suitable for iron determination. The ion-pair shows )~max at 505 nm (s6.0 × 104) and obeys Beer's law from 0 - 2 ppm of iron concentration. The following ions (in ~Lg) can be tolerated Hg 2 + (500); A13 + (400); Bi 3 + (300); Cu 2+ (250); Cd 2+, Mo 6+ (/50); Pb 2+, Ti 2+, Mn 2+, Cr 3+, V s+ (100); Zn 2+ (75) and Sn 2+ (50) are masked if the extraction is carried

670 2 Particular products and fields of application

out in presence of 5 ml of 1 x 10 3M EDTA. Co 2÷ and Ni 2+ interfere. The method is applied to determine iron in titanium base alloys. - J. Indian Chem. Soc. 66, 837--839 (1989). Dept. Chem., Nagarjuna Univ., Nagarjuna Nagar (IND) H.B. Singh

Spectrophotometric determination of molybdenum in some alloys and steels using quinalizarin and cetylpyridiuium chloride. M.T.M. Zaki, F.M. E1- Zawawy, A.K. Abdel-Kader and M.M. Abdalla.

A new sensitive and rapid method is proposed for the spectrophotometric determination of molybdenum in some cobalt and nickel base alloys and steels. The procedure is based on the formation of a molybdenum(VI)-quinalizarin complex in an aqueous micellar solution of cetylpyridinium chloride (CPC) at pH 3.2-4.2. Beer's law is obeyed over the range 0.05-0.60 ppm of molybdenum. The apparent molar absorptivity of the complex is (1.27_+0.01)x 10 s 1 tool -~ cm ~ at 580 nm and the sensitivity index is 0.0007 ~tg cm-2 of molybdenum. The experimental factors which affect the color reaction were investigated throughly. The method is free of interference from most of the common metal ions. - Anal. Sci. 6, 6 1 - 6 5 (1990). Dept. Chem. Fac. Sci., Ain Shams Univ., Abbassia, Cairo (ET)

Selective spectrophotometric titration of molybdennm(VI) and tungsten(VI) in fluoride organo-aqueous solutions. V. V. Kuznetsov and V.N. Reshetnikova.

Die vorgeschlagene selektive Bestimmung yon Mo(VI) and W(VI) allein und in gegenseitigen Gemischen beruht auf der spektralphotometrischen Titration der Anionenfluoridkomplexe der Zusammensetzung [MoO2F4] 2- (log [31 = 4,28; log 132 = 6,90) bzw, [WO2F4] 2 (log 131 = 4,47; log [32 = 7,08) mit K÷-L6sung in iv¢/il3rigem Dimethylsulfoxid (DMSO) gegen Nitchromazo als Indicator ()~m~ = 632 nm). Auf diese Weise k6nnen Mo(VI) und W(VI) auch neben Fe, Cu, N i, V, Cr und anderen Metallen in ihren Legierungen selektiv bestimmt werden. Ar- beitsweise, a)Bestimmung yon Mo(VI) bzw. W(VI): 0,5 ml Probel6sung (3 - 5 0 0 pg Mo bzw. 3 --400 gg W enthaltend) werden in einer Titrierkii- vette mit 0,3 ml 1 M HF, 0,15 ml 0,1%iger Nitchromazo- und 0,3 ml 0,1 M HNO3-L6sung versetzt, mit 13,5 ml DMSO vermis.cht, mit Wasser auf 15 ml verdfinnt und mit 10- 3 _ 10- 2 mol/1 KC1-L6sung spektralphotometrisch titriert, b) Bestimmung von W in Stfihlen: 0 ,2-0,5 g Sp/ine werden in einem Teflonbecher in 5 ml konz. HF und 3 ml konz. HNO3 durch Erw/irmen gel6st und die L6sung wird nach dem Erkalten in einem 100 ml-MeBkolben mit Wasser zur Marke erg~inzt. 0,5 ml davon werden nach Zusatz yon 0,2 ml 0,1 M EDTA-L6sung weiter wie.oben angegeben spektralphotometrisch titriert, c) Bestimmung von Mound W nebenein- ander in St/ihlen: 0 ,7-1 ,0 g Sp/ine werden wie oben beschrieben mit HF/HNOa aufgeschlossen. Der Niederschlag wird abfiltriert ,das Filtrat mit Wasser auf 100 ml verd/innt und weiter wie oben beschrieben bear- beret. - Zh. Anal. Khim. 44, 2079--2083.(1989) (Russisch, mit engl. Zus.fass.). Mendeleev Chem. technol. Inst., Moskau (SU) F. Jancik

Analysis of placer platinum with sample decomposition by liquid-phase chlorination in sealed ampules. A.N. Kurskii, A.V. Mandrugin, E.V. Tarasova and N.L. Fishkova.

Von mehreren Aufschlul3varianten yon Rohplatinproben zwecks der AAS-Bestimmung von den anwesenden Edel- sowie anderen Metallen, bewfihrte sich als die geeignetste die Probenchlorierung in flfissiger Phase in einer eingeschmolzenen Ampulle. Zu diesem Zweck werden 0,1-0,3 g feinzermahlene Probe (Korngr6Be 0,1 -0 ,2 mm) in einer Ampulle aus Mo-Glas (L/inge 20 cm, i.D. 6 mm, Wandstfirke 1 ,5 -2 mm) mit 8 ,5 - 9,0 ml konz. HC1 versetzt, und der Ampulleninhalt wird in einem mit Aceton + CO2 gekiihlten Dewar-Gef/il3 vereist; nun l~i13t man in die Ampulle flfissiges Chlor bis 0 ,5-0,8 cm H6he zufliessen; die Ampulle wird eingeschmolzen, in einen Stahlschutzbehfilter eingelegt und in einem Ofen 10 h auf 250°C erhitzt. Nach der Abkiihlung wird der Ampullenin- halt unter dem Mikroskop beobachtet und falls die Probe nicht vollkom- men aufgel6st ist, mug die Erhitzung der Ampulle verlfingert werden. Nach dem Offnen der Ampulle wird der Ampulleninhalt in einen 100 ml-Mel3kolbe n quantitativ tiberfiJhrt und mit 2 M HC1 zur Marke er- g/inzt. Die anschliel3ende Bestimmung von Pt, Pd, Ir, Rh, Ru, Fe, Ni, Cu, Cr und Au wird mittels AAS durchgefiihrt. Nur Os wird nach dem Abdestillieren aus H2SO4-L6sung in 1%iger Thioharnstoffl6sung gesammelt und spektralphotometrisch bestimmt. Die Ergebnisse des

vorgeschlagenen Verfahrens stimmen mit denjenigen der Neutronenakti- vierungsmethode gut iiberein (Tabelle). - Zh. Anal. Khim. 44, 2091 - 2095 (1989) (Russisch, mit engl. Zus.fass.). Zentr. Inst. geol. Forsch. Bunt- u. Edelmetalle, Moskau (SU) F. Jancik

Calculation of concentrations of hydrochloric and citric acids together in a mixture with hydrolysable salts. T. Michalowski, A. Rokosz, P. Kogcielniak, M. Lagan and J. Mrozek.

A standard additions method based on the results of titrations in isomolar titrand-titrant systems was applied to the determination of hydrochloric and citric acids in a mixture with various hydrolysable salts or their mixtures, at high ionic strengths. The concentrations of the acids were found by applying the iterative MINUITS procedure to a semi- empirical regression function expressed by the Pad~ approximant. The results obtained were characterised by good accuracy and precision. - Analyst 114, 1689-1692 (1989). Dept. Anal. Chem., Fac. Chem., Jagiellonian Univ., Krak6w (PL)

Chemical analysis by inductively coupled plasma atomic emission spectrometry of semiconductiug ceramics of barium titanate doped with various metal oxides. J.C. Farifias and M.F. Barba.

The Ba and Ti macroconstituents as well as the impurities and dopants content (A1, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Nb, Ni, P, Pb, Si, Sr, W, Zn and Zr) in a dense ( > 98% theoretical) barium titanate sample have been determined by inductively coupled plasma-atomic emission spectrometry after one of these decomposition routes: (a) decomposition with HC1 in a PTFE-lined pressure vessel, (b) fusion with Na2CO3 in a platinum crucible, and (c) fusion with Li2B407 in a graphite crucible. Matrix effects were taken into account. Detection limits for minors and trace elements were determined. High sensitivity and good precision were attained. - Mikrochim. Acta 1989, III, 299--308. Inst. Cerfimica y Vidrio (C.S.I.C.), Chem. Anal. Dept., Arganda del Rey, Madrid (E)

Determination of trace impurities in electronic grade quartz: Comparison of inductively coupled plasma mass spectroscopy with other analytical techniques. H. Baumann and J. Pave1.

An analytical procedure for the determination of uranium and thorium in the sub-ng/g range as well as of other trace elements in the ng/g to pg/g range in high purity quartz samples is described. The results obtained by ICP-MS are compared to those obtained by other analytical techniques (instrumental neutron activation analysis, flame atomic absorption spectrometry, Zeeman graphite furnace atomic absorption spectrometry, total reflection X-ray fluorescence analysis, direct current arc optical emission spectrometry, and X-ray fluorescence analysis. For the ICP-MS measurements, the decomposition of the samples is carried out with HF/HNO3/H2SO4-mixtures. The results obtained by the different methods show reasonable agreement. For uranium and thorium, ICP- MS proves to be the most sensitive method: detection limits of about 50 pg/g can be achieved for both elements. - Mikrochim. Acta 1989, III, 413-422. Central Anal. Dept., Ciba-Geigy Ltd., Basle (CH)

Characterization of II - VI semiconductor materials using surface analytical techniques. M.H. Kibel.

The production, properties and structure of I I - V I semiconductor materials are topics of increasingly intense research activity. This paper discusses the use of the surface analytical techniques x-ray photoelectron spectroscopy, Auger electron spectroscopy and energy-dispersive x-ray spectroscopy to study and characterize these materials, and hence assist in understanding the growth process. - X-Ray Spectrom. 19, 7 3 - 77 (1990). Appl. Sci. Branch, Telecom Australia Res. Labs., Clayton, Victoria (AUS)

Study of K-absorption edge of selenium in the glassy semicondueting S%oo-xInx system. A. Kumar, M. Husain, S. Swamp, A.N. Nigam and A. Kumar.

The shift of the K-absorption edge (AEK) was measured in Selo0- xInx binary system where 0 ~< x ~< 30. The K-edge of Se pregressively shifted toward the lower energy side as the In concentration increased from 0 to 15 at.-%. However, a higher concentrations, the relative shift started to decrease. The results are in accordance with Pauling's concept to electronegativity and indicate that the nature of the bonds is iono-

2.1 Inorganic industrial products 671

covalent in these glasses, as found in many crystalline solids. The composition dependence of the edge shift is also discussed in terms of the structure of Se. - X-Ray Spectrom. 19, 2 7 - 2 8 (1990). Dept. Physics, Jamia Millia Islamia, New Delhi (IND)

Measurement of vanadium impurity in oxygen-implanted silicon by isotope dilution and resonance ionization mass spectrometry. S. Mayo, J.D. Fassett, H.M. Kingston and R.J. Walker,

The combined analytical capabilities of isotope dilution, laser-induced resonance ionization spectroscopy, and mass spectrometry, integrated in the resonance ionization mass spectrometry technique (RIMS), have been evaluated as a tool for quantitative elemental impurity analysis of SIMOX (separation by implanted oxygen), a new silicon-based material prepared by oxygen implants. The vanadium impurity content was measured in the top crystalline SIMOX film and the oxygen-synthesized buried oxide layer in commercial wafers, resulting in 0.14 pg/g _+ 20%, or 1.7 x 1015 atoms/cm 3. A similar analysis on the substrate bulk shows about 30 times lower vanadium impurity levels. The origin of this contamination may be linked to the oxygen implant, although no modeling for it is offered here. The sensitivity of RIMS to vanadium is in the pg/g range. The accuracy of results is limited by the uncertainty in the blank, in view of the low total vanadium content in the specimen. Anal. Chem. 62, 240-244 (1990). Semicond. Electron. Div., Nat. Inst. Stand. Technol., Gaithersburg, MD (USA)

Carbon determination in Si3N4 by slurry atomization ICP-AES. I. Varga, G. Zfiray, J. Sz~pv61gyi and G. K6nya.

Carbon content in silicon nitride powders having mean particle size below 5 pm was determined by slurry atomization (ICP-AES). A complete atomization of the solid particles was observed in a low power argon-ICP. The blank value of the carbon signal was reduced by using high purity argon, fresh bidistilled water and an extended torch. Silicon nitride slurries were analyzed by calibration and addition methods with acetic acid as reference. The results were in good agreement with data obtained by a LECO carbon analyzer. A blank restricted detection limit of0.018% was calculated. The relative standard deviation of the analysis was below 7%. - Mikrochim. Acta 1989, III, 381 387. Res. Lab. Inorg. Chem., Acad. Sci., Budapest (H)

Determination of impurities in zirconium carbide and nitride by inductively coupled plasma atomic emission spectrometry. T. Ishizuka, Y. Uwamino, H. Morikawa, Y. Iida and A. Tsuge.

Zur Bestimmung von Metallverunreinigungen in kommerziellen ZrC- und ZrN-Pulvern wird bier ein ICP-AES-Verfahren nach Sgureaufschlu3 der Proben eingesetzt. Die Proben werden in HNO3 + H F (3:1) durch 1 h Erwfirmen auf 50--60°C gel6st, nach Abkfihlung wird 4%ige Bor- s/iurel6sung zugeffigt, die Probe geeignet verd/innt und die ICP/AES- Messungen durchgefiihrt. Die Gehalte an A1, Ca, Co, Cr, Fe, Hf, Mg, Mn, Mo, Na, Nb, Ni, Si, Ti, V und W in den untersuchten ZrC- und ZrN-Proben werden mitgeteilt. Ffir alle Elemente, mit Ausnahme yon Na, ist die ICP-AES-Methode empfindlicher als die AAS. - Anal. Sci. 6, 315-317 (1990). Chem. Dept., Governm., Ind. Res. Inst., Kita, Nagoya (J) R.H.S.

Coulometric determination of carbon in fluorine-containing welding flux. V.Yu. Persits, A.V. Shatunova and L.N. Vasil'eva.

Es wird die coulometrische C-Bestimmung in fluorhaltigen SchweiB- flul3mitteln (FSFM) mit 0 ,03-1,0% C beschrieben, fJbliche FSFM enthalten 2,5 -- 90% CaF2, das bei Temperaturen fiber I00°C mit Wasser- dampf unter Freisetzung von HF bzw. weiteren flfichtigen Fluoriden reagiert. Die vorgelegte Methode beruht auf der Verbrennung von 0,5 g Probe mit CuO in einem Porzellanschiffchen bei 1250 1300 °C in rei- nero und trockenem Sauerstoffstrom; HF bzw. weitere Verbrennungs- produkte werden in einem bei 1000°C ausgegl/ihtem und auf beiden Rohrenden mit 0 , 3 - 0,4 ml Wasser befeuchtetem Kieselgel-geffillten U- Rohr (100 x 10 mm) adsorbiert; die HF-Adsorptionsvollstfindigkeit in dem U-Rohr wird mit Kongo-Papier kontrolliert. Gearbeitet wurde in einer geeigneten Apparatur, deren schemat. Abbildung und Detailbe- schreibung beigef/igt sind. Das freigesetzte CO2, das dem C-Gehalt entspricht, wird im Sauerstoffstrom in den coulometrischen Titrations- analysator gefiihrt, in dem sein Gehalt aufgrund der pH-Anderung aus-

gewertet wird. - Zh. Anal. Khim. 44, 1676- i679 (1989) (Russisch, mit engl. Zus.fass.). Forsch.ind. Verband f. Technol. d. Maschinenbaus, Moskau (SU) F. Jancik

Zur coulometrischen Bestimmung yon phosphoriger S~iure in Phosphor- siiure und Phosphorpentoxid. H. Opel und H. Matschiner.

Zur schnellen und genauen H3PO3-Bestimmung wird die direkte coulometrische Titration vorgeschlagen. 0,01 bis 0,1% H3PO3 k6nnen als Verunreinigung in P205 und HaPO~ auftreten. 10,0 g Probe werden auf 50 ml verdfinnt, doch empfiehlt es sich vor dem Aufffillen durch Zugabe yon NaOH-L6sung weitgehend, etwa bis zur Stufe Na2HPO~, zu neutra- lisieren. 1 ml dieser L6sung werden mit 45 ml Reagensgemisch versetzt. Dieses enthfilt 100 g KBr, 200 g KHCO3 und 22 g K;CO3 im Liter, der pH-Wert liegt bei 9. Die Messung erfolgt mit dem Coulometer NT-I, bei galvanostatischer Arbeitsweise ausgestattet mit einer stromkontrollier- ten Annfiherung an den Endpunkt, der biamperometrisch ermittelt wird. Bei Gehalten yon 0,0520% H3PO3 betrug die Standardabweichung s = 0,0024 (n = 10). Bei Versuchen mit reinen H3PO3-L6sungen wurden Zu- sfitze von jeweils 0,10 mg und 1,00 mg mit Abweichungen v o n + 1% relativ wiedergefunden, die Standardabweichung lag bei 0,001 (abs). Vergleiche mit der titrimetrischen Standardmethode zeigen sehr guts Ubereinstimmung. Bei letzterer versetzt man die mit NaHCO3 neutrali- sierte Probe mit 0,1 N Broml6sung im Uberschug, spfiter mit 0,1 N H3AsO3-L6sung im fQberschug und titriert danach mit 0,1 N Broml6- sung gegen Indigocarmin als Indicator. Z. Chem. 29, 11 ,411-412 (1989). VEB Agrochemie Piesteritz, Wittenberg-Lutherstadt (DDR)

A.M. Roscovanu

Investigation of sulfitic gold baths by means of voltammetric measurements. H. Grogmann and A. Hollfinder.

Auger der fQberwachung von Prozegbfindern mit klassischen Analy- senmethoden kommt auch die Voltammetrie zum Einsatz. In der vorliegenden Arbeit wird gezeigt, dab mit Hilfe von Stromdichte-Potentialkur- yen der EinfluB yon Cyaniden, Tensiden und feindispersem Kohlenstoff als st6rende Fremdstoffe in sulfidischen Goldbfidern ermittelt werden kann. Darfiber hinaus lfiBt sich mit diesem Verfahren der Gehalt und die Wirkung des in diesen Bfidern verwendeten Glanzzusatzes aufAs203- Basis aus dem Verlauf der Kurven erkennen. Als Megelektrode mit den am besten reproduzierbaren Werten erwies sich eine Scheibenelektrode, die aus einem in Kunststoff eingebetteten Feingoldstab besteht, und die vor jeder MeBreihe spezielI behandelt wurde, um sis von geringsten Oberfl/ichenverunreinigungen zu sfiubern. - Metalloberflfiche 44, 249 - 252 (1990). Entwickl. Galvanotechnik, Doduco GmbH, D-7530 Pforz- helm W. Czysz

Coated-wire ion-selective electrodes based on chloride and cyanide complexes of zinc and their application to zinc monitoring in the electrogalvanizing process. M.J. Rocheleau and W.C. Purdy.

Verff. untersuchen das elektrochemische Verhalten der Chlorozin- kat(II)- und Cyanozinkat(II)-Anionen mit dem Ziel, auf dieser Basis ein potentiometrisches Bestimmungsverfahren ffir Zink auszuarbeiten. Dazu wird mit einer elektroaktiven Membran gearbeitet, die entweder das Chlorozinkat- oder Cyanozinkatsalz des Tricaprylylmethylammoni- um-Kations (Aliquat 336S) enth/ilt, und die als fJberzug auf einer Platin- drahtelektrode (Beckman) plaziert wird. Beide Modifikationen dieser Elektrode zeigen ausgezeichnete Responseeigenschaften f/Jr Zink im Konzentrationsbereich 10- s bis 10-1 M Zn(II) in Chlorid- bzw. Cyanid- 16sungen. St6rungen verursachen lediglich einige UbergangsmetaIle: Cu(II), Cd(II) und Hg(II). Das Verfahren signet sich ffir die Bestimmung von Zink in Galvanisierbfidern und deren Abw/issern. - Anal. Lett. 22, 2541-2559 (1989). Dept. Chem., McGill Univ., Montreal, Quebec (CDN) W. Czysz

Rapid determination of bismuth in electrolytes and in arsenic compounds. A.T. Pilipenko and L.N. Demutskaya.

Zur schnellen extraktions-photometrischen Bestimmung von Bi in galvanischen B/idern zur Sn-Bi Beschichtung und in As-Verbindungen wird der Komplex von Bi(III), der in Gegenwart von Natriumpolysulfid (in 30fachem 1]berschug gegen Bi) und Cetyltrimethylammoniumbro- mid (im I0fachen Uberschug)im alkalischen Milieu von 1% Ammoni- nmcitrat mit 1,2% Weinsfiure gebildet wird, in Chloroform extrahiert


und der Extrakt bei 444 n m (Emax : 9,7 × 103) photometriert. Dos Beer- sche Gesetz gilt im Bereich 3 - 2 1 0 gg Bi/10 ml. Die Bestimmung von Bi wird durch 10000fach Sn(IV), As(III,V), A1, Ga(III), Ge(tV), Mo(VI) und W(VI), 400fach V(V), 100fach Sb(III,V), 18fach Fe(III), 3fach Cd(II), lfach Pb(II) und 0,Sfach Cu(II) nicht gest6rt. Der sr-Wert betrug 0,02 bei Gehalt 2,5% Bi im Elektrolyt. - Zavodsk. Lab. 55, 3 - 5 (1989) (Russisch). Inst. f. Kolloid u. Wasserchem., Akad. Wiss., Kiev (SU)

E. Svatek

Ion chromatography of inorganic anions in brine samples. P.F. Subosa, K. Kihara, S. Rokushika, H. Hatano, T. Murayama, T. Kubota and Y. Hanaoka.

An ion chromatographic method for separating and detecting anions in brine samples is described. Nitrite, bromide, nitrate, and sulfate ions in brine samples are well separated when chloride ion concentration in the sample solution is below 2000 ppm. However, at higher chloride concentrations, nitrite and chloride peaks are not resolved. Low level nitrite ion in the brine sample is separated from a major chloride ion by a heart-cutting and recycling system. After elution, the unresolved portion, including the nitrite ion, is cut and trapped in a 10-ml sample collecting loop and reinjected on the column by using 6- and 4-port valve systems. The detection limit of nitrite spiked in the seawater sample is 0.5 ppm. - J. Chromatogr. Sci. 27, 680-684 (1989). Dept. Chem., Fac. Sci., Univ., Kyoto (J)

which were extracted to the air. The samples were taken from the oil carter of a motor after different running times (0 km to 10.000 kin). The change of the amount of the trace elements (Cr, Fe, Co, Ni, Mo, W, Ti, C, A1, Mn) was detected with increasing time of use. Comparing the elemental composition of the pure and used oil samples allows conclusions which elements came from the material of the engine block due to friction or sucking in of polluted air. This method is effectiv for testing, controlling and comparing the different types of lubricants and also the different engine parts and materials. The friction wear of the engine material can also be measured. - J. Radioanal. Nucl. Chem. 130, 263-268 (1989). Inst. Nucl. Res. Hung. Acad. Sci., Debrecen (H); Fac. Bus. Educ. (Kuwait) G. Peters

Determination of tetraethyl lead in petrol fuels by atomic absorption spectrometry. J. Romanowski.

Direct determination of lead content in fuels has been performed by atomic absorption spectrometry using analytical line 217.0 nm and acetylene-air flame. The measurements were carried out after diluting samples with aviation fuels. The analytical curve was prepared using the solution of lead cyclohexabutyrate in lead-free aviation fuel. The method may be applied for determination of tetraethyl lead content in engine petrol fuels and in either kerosene products in the range of lead content from 0.05 to 1.10 g 1-1. _ Chem. Analit. 34, 297 - 300 (1989) (Polnisch, mit engl. Zus.fass.). Military Res. Centre Liquid Fuels, Warszawa (PL)

Ion chromatographic separation for analysis of radiostrontium in nuclear reprocessing solutions of high ionic strength. J.D. Lamb, F.R. Nordmeyer, P.A. Drake, M.P. Elder, R.W. Miles and R.P. Lash.

Determination of 9°Sr in nuclear fuel reprocessing solutions can be facilitated by a preparatory separation using analytical ion chromatography (IC). Furthermore, a novel acid suppression system is described which permits IC separation even in the presence of very strong (0.33 M) acid. Following acid suppression (where needed), Sr 2 ÷ is concen- trated and separated from most other solution components by selective adsorption on cation concentrator columns. Cation species retained on the concentrator columns with strontium are subsequently separated on a cation IC column. The Sr 2 ÷ peak aliquot is collected for subsequent radiostrontium analysis by liquid scintillation counting of the beta activity. Results have shown quantitative separation and recovery of strontium. The entire separation system is automated under computer control and is able to handle samples of large (500 ml) and small (gl) sizes. - J. Radioanal. Nucl. Chem., Art. 134, 317-331 (1989). Dept. Chem., Brigham Young Univ., Provo, UT (USA)

2.2 Organic industrial products

Measurement of mercaptans in gasoline. W. Lei, P.K. Dasgupta, S.D. Matza and D.C. Olson.

In an r-FIA single-line manifold, 10-pl portions of 5,51-dithiobis(2 - nitrobenzoic acid) and 2% (v/v) ethylenediamine in methanol/acetone (80:20) are injected from pressurized containers via high-speed on/off valves into a flowing gasoline stream. The reaction product, 2-nitro-5- mercaptobenzoate, is detected optically at 412 nm after a reaction time of ~ 15 s. The system is intended for the measurement of mercaptans in the 0 - 2 mM (0 - 64 ppm S) concentration range. The response for C1 - C 10 n-mercaptans ranges from 0.766 - 0.159 mAU/mM, the response to C1 - C 5 n-mercaptans is 630 mAU/mM (_+ 18.5% RSD). The response ratio of C1 and C5 mercaptans is 1:0.653. The system permits extreme conservation of reagents; only 10 gl of each reagent is consumed per determination. - Mikrochim. Acta 1989, lII, 35-41 . Dept. Chem. Biochem., Texas Tech Univ., Lubbock, TX (USA)

Trace element analysis of motor oil by CPAA method on external proton beam. F. Ditrol, I. Mahunka, S. Takacs and S. Self E1-Nasr.

Normal motor-oil was investigated to detect certain trace elements under ppm level by CPAA method using 12 and 18 MeV proton beams,

Characterization of specific interaction capacity of solid surfaces by adsorption of aikanes and alkenes. Part I: Adsorption on open surfaces. M. Sidqi, G. Ligner, J. Jagiello, H. Balard and E. Papirer.

Adsorption of a series of alkenes on initial and grafted silica surfaces has been studied by GC at ~nfinite dilution. Taking the n-alkanes adsorption as a reference, the influence of the double bond in the hydrocarbon adsorption phenomena has been examined. Thermodynamical parameters have been calculated which allow the estimation of specific parts of the alkene/silica interactions. - Chromatographia 28, 588- 592 (1989). Centre Recher. Phys. Chim. Surfaces Solides, C.N.R.S., Mulhouse (F)

Spectrophotometric determination of traces of monoethylene-glycol. R. BelSeva and M. Smukov.

The proposed method includes the following stages: absorption for monoethylene-glycol in water (flow rate 0.5 l/min, time 1 h), oxidation of absorbed monoethylene-glycol to formaldehyde with periodate (0.05 ml of 0.4% aqueous solution of KIO4), decomposition of the excess KIO4 with sodium sulfite (0.25 ml of 2.5% aqueous solution) and determination of formaldehyde with chromotropic acid (0.8 ml of 0.5% aqueous solution) in H2SO4 medium (6.5 ml of conc. HzSO4). The resulting colour product has )~ .... = 570 nm and molar absorptivity ~ = 15.7 1 mo1-1 cm -1. The colour is stable within 24 hrs. Beer's law is obeyed in the range of 1 - 1 0 gg monoethylene-glycol. The method is applied to the analysis of waste gases and liquified gas phases. - Neft i himija 4, 9 - 1 1 (1988).

Determination of cyclodextrin-guest association constants by competition with indicator dyes. W. Hirsch, C.K. Choy, K.W. Ng and V. Fried.

~- und [3-Cyclodextrin bilden Einschlugverbindungen innerhalb der Kavit/iten der Molekiile. Andererseits ist bekannt, dab die Cyclodextrine die rote, saure Form yon Methylorange, aber ouch dos basische, rosafar- bene Phenolphthalein in L6sungen komplexieren und entffirben. Bei der Zugabe konkurrierender farbloser Einschlugverbindungen kommt es zur Freisetzung der Indicatorspecies mit gleichzeitigem Wiederauftreten der urspriinglichen Ffirbung. Dieses Konkurrenzverhalten wird fiir einige biologisch interessierende Verbindungen (z.B. Benzoes~iure, p- Aminobenzoesfiure, p-Toluolsulfons/iure, L-Tryptophan, Citronen- s/lure, Carbonat, Citrat, Oxalat) untersucht und dabei dos Wiederer- scheinen der Methylrot- bzw. Phenolphthaleinffirbung photometrisch verfolgt. Auf Grund der Versuchsergebnisse wird ein mathematisches Modell zur Berechnung der Cyclodextrin-,,guest"-Assoziationskonstan- ten der obengenannten Verbindungen entwickelt. - Anal. Lett. 22, 2861-2869 (1989). Dept. Chem., Brooklyn Coll., City Univ. New York, Brooklyn, NY (USA) W. Czysz

2.2 Organic industrial products 673

Gaschromatographische online-Analyse von Produkten der katalytischen Oxidation yon Naphthalin im geschmolzenem Salz bei 425°C. M.S. Medi- magh und M.L. Bouguerra.

Mehr als drei Millionen Tonnen Phthals/iureanhydrid werden weltweit j/ihrlich durch Oxidation von Naphthalin erzeugt. Das Verfahren 1/iuft bei 425°C in einer Schmelze des eutektischen Gemisches KzSO4/KzS207 an V2Os, Kontakten ab. Mit Hilfe eines in den Reaktorauslal3 geschalte- ten Gaschromatographen kann online, ohne Zeitverzug, die Konzentra- tion der beteiligten Substanzen Naphthalin, Phthals~iureanhydrid und Naphthochinon-l,4 gemessen werden. Gerfit Intersmat IGC 121 FL; Sfiule Silicon61 SF 96 auf Chromosorb WAW; Helium als Tr/igergas; Detektor FID. Anderungen der Verfahrensparameter im Reaktor werden dutch Anderungen im C hromatogramm sofort erkannt. - Analusis 17, 543 - 546 (1989). Dept. Chim. Fac. Sci., Tunis (TN)

Identification of side products formed in the analysis of polymethylsiloxane liquids of linear structure by reactive gas chromatography. A.M. Filippov and V.N. Bochkarev.

Fliissige Polymethylsiloxane (PMS) allgemeiner Zusammensetzung (CH3)3Si-O-[Si(CH3)2-O]n-Si(CH3)3 (I) unterscheiden sich je nach der Provenienz durch den Gehalt an Dimethylsiloxangliedern (M2) und Trimethylsiloxan-Endgruppen (M3); ihr Verhfiltnis wird iiblicherweise mittels der Reaktions-Gaschromatographie (RGC) aufgrund der Reak- tion (I) NanV~, (CH3)2SiF2 (II) + (CH3)3SiF (III) bestimmt. Die GC- Bestimmung von II (Siedepunkt 2°C) sowie von III (Siedepunkt 16°C) unter isokratischen Bedingungen macht keine Schwierigkeiten. Es wurde jedoch festgestellt, dab die obenangegebene Reaktion durch das Verh~iltnis von PMS und NaHF2, die Temperatur und Reaktionsdauer beein- flul3t wird. Nur bei einem 6fachen Uberschug von NaHF2 bei Reaktor- temperatur 200°C und bei Durchfiihrung der GC-Bestimmung der entstehenden Reaktionsprodukte unter Temperaturprogrammierung ist die RGC-Analyse von PMS, bei der I quantitativ zu II, III und zuffillig auch anderen Stoffen umgewandelt wird, verlfil31ich. Aufdiese Weise wies man nach, dab neben den schon erwfihnten Stoffen im Sinne der obenange- ffihrten Reaktion noch weitere hochsiedende lineare Verbindungen, na- mentlich co,c0'-Difluorsiloxane und co-Fluor-co'-hydroxysiloxane, deren Struktur mittels der Massen-Spektrometrie bestfitigt wurde, entstehen k6nnen. Die Diskussion des Reaktionsmechanismus ihrer Bildung sowie genaue Bedingungen der PMS-Analyse mittels RGC s. Original. - Zh. Anal. Khim. 44, 2043-2048 (1989) (Russisch, mit engl. Zus.fass.). Forsch.inst. Chemie Technol. elementorg. Verbind., Moskau (SU)

F. Jancik

Effect of hydrogen substitution on the mass spectrometry and size-exclusion chromatography of perfluorinated polyether fluids as determined by time-of-flight secondary ion mass spectrometry. S.M. Hues, J.R. Wyatt, R.J. Colton and B.H. Black.

The secondary ion mass spectrometry (SIMS) of perfluorinated polyether (PFPE) fluids reveals an extensive series of high-mass ions whose distribution depends on the molecular weight, structure, and fragmentation pattern of the oligomers. Analysis by size-exclusion chromatography (SEC) showed the fluids to consist to either single or double component systems. Aliquots of the components were collected from the SEC column effluent and subsequently analyzed by time-of-flight SIMS. The oligomer distributions of the PFPE fluids were found to differ both in their number average molecular weight and in the degree of hydrogen substitution. The observed SEC separation was dependent on the molecular weight and the effect of hydrogen substitution on the molecular volume. - Anal. Chem. 62, 1074-1079 (i990). Chem. Div., Naval Res. Lab., Washington, DC (USA)

Differenz-Thermo-Analyse zur Identifizierung yon Polyurethan-Produk- ten. H. Gross.

Eine Ubersicht fiber m6gliche Methoden zur Beurteilung yon Polyure- than-Erzeugnissen und anderer Polymere. Hierfiir bieten sich die Diffe- renzthermoanalysen (DTA), die Dynamische Differenzkalorimetrie (DDK bzw. DSK fiir differential scanning calorimetry), die Thermogra- vimetrie (TG) und die Thermomechanische Analyse (TMA) an. Die aufgeffihrten Methoden werden kurz erl/iutert. Der Autor gab dann der

Thermoanalysestation TA 3000 yon Mettler Instruments den Vorzug. Es konnte die Kristallinit/it und Oxidationsbest~ndigkeit von vernetztem Polyethylen, Kristallinit/it und Zersetzungsbeginn von Polyethylen-Roh- ren ermittelt werden. - LaborPraxis 14(t/2), 3 8 - 4 0 (1990). Staatl. Materialpriifungsamt (MPA) Nordrhein-Westfalen, Dortmund (D)

H. Hoffmann

Size exclusion chromatography of poly(methyl vinyl ether-co-maleic anhydride) (PMVEMA). I. The chromatographic method. C.S. Wu, L. Senak and E.G. Malawer.

The optimum size exclusion chromatographic conditions for poly- (methyl vinyl ether-co-maleic anhydride) (PMVEMA) were found to consist of Waters Ultrahydrogel columns of pore sizes I20, 250, 1000, and 2000 A. with an Ultrahydrogel guard column and a mobile phase of pH 9 buffer with 0.2 M LiNO3. Sample recovery was found to be 100%. PMVEMA exists as an anionic polyelectrolyte in this mobile phase. PMVEMA was irreversibly adsorbed onto the same columns when analyzed in pH 2.5 phosphate buffer (0.1 M or 0.2 M). Attempts to analyze PMVEMA in THF, THF (1% acetic acid), THF (5% trichloroacetic acid), and DMF (0.1 M LiNO3) using PL gel columns were not successful due to adsorptive effects or electrostatic interactions. - J. Liquid Chromatogr. 12, 2901-2918 (1989). Gaf Chem. Corp., Wayne, NJ (USA)

HPLC of synthetic polymers. Characterization of polystyrenes by high- performance precipitation liquid chromatography (HPPLC). R. Schultz and H. Engelhardt.

The advantages and disadvantages of high-performance precipitation liquid chromatography have been demonstrated for polystyrene homopolymers. Depending on the mobile phase composition at the dissolution point of the polymeric sample and surface properties of the stationary phase, elution is governed either by a solution process or by adsorption. A contribution by adsorption was noticed on silica as well as on reversed phases based on silica with a normal phase gradient of increasing polarity (heptane to dichloromethane). Elution was solely governed by solubility of the polymers on both types of stationary phase for polystyrenes with a molecular weight above 35000 and reversed phase gradient of decreasing polarity (methanol to dichloromethane). Under these conditions an identical dependence of elution solvent composition on sample size was found as for turbidity titrations. Due to differences in the velocity of the eluent front and the polymeric sample with porous stationary phases the polymers can be eluted as colloidal solutions. Non-porous stationary phases are superior in this respect because the velocities of eluent and solutes are identical. - Chromato- graphia 29, 2 0 5 - 213 (i 990). Angew. Physik. Chem., Univ. Saarbriicken (D)

Rapid survey analysis of polymeric materials by laser ablation-inductively coupled plasma spectrometry. An analytical note. P.K. Booth and C.W. McLeod.

An Nd-Yag laser (1064 nm) in combination with a multichannel emission spectrometer was used for rapid survey analysis of polymers and paints. A novel design feature of the ablation chamber was the incorporation of a graphite furnace to effect electrothermal pretreat- ments of samples. Transient emission signals were studied as a function of laser operating mode, laser duration and flashlamp energy. - Mikrochim. Acta 1989, III, 2 8 3 - 289. Dept. Chem. Sheffield City Poly- technic, Sheffield (GB)

Analysis of multicomponent dye samples with laser microprobe mass spectrometry (LMMS). J.A. Bennett, E.A. Schweikert, L. van Vaeck and F.C. Adams.

Proben mit bis zu vier verschiedenen organischen Farbstoffen k6nnen durch LMMS bestimmt werden. Da die LMMS in der Lage ist, jede Verbindung im Gemisch einzeln nachzuweisen, erh~ilt man falsche Ergeb- nisse bei nicht-homogenen Proben. Deshalb ist es n6tig, zur qualitativen Identifizierung der Verbindungen eine Mitteilung der Spektren vorzu- nehmen. Quantitative Ergebnisse sind nur beschrfinkt auf Grund der Unterschiede in den Ionisationsausbeuten der einzelnen Farbstoffe zu erhalten. - J. Trace Microprobe Techn. 7, 279-292 (1989-90). Dept. Chem., Texas A&M Univ., College Station, TX (USA) R.H.S.


Some observations on the extraction of triphenylmethane dyes by ion-pair formation with amines as counterions. R. Izquierdo-Hornillos, J.L. Peral Fernandez and B. Cafias-Montalvo.

Triphenylmethane dyes such as xylenol orange, glycine, cresol red, and methylthymol blue by formation of ion pairs with diphenylguanidine, Amberlite LA-2, and tri-n-octylamine have been extracted into several solvents. The influence of the amine/solvent system, the concentration of amine, and the presence of electrolytes and the distribution parameters are discussed. As an application, the extraction of glycine thymol blue with Amberlite LA-2 solved into 1-pentanol as the most suitable extracting system was carried out. - Microchem. J. 40, 263-270 (1989). Dept. Anal. Chem., Fac. Chem. Sci., Univ. Complut., Madrid (E)

Reversed phase high-performance liquid chromatographic analysis of tri- phenylphosphine in a reaction mixture. J.E. Haky, D.M. Baird and S. Falzone.

Verff. beschreiben ein isokratisches RP-HPLC-Verfahren zur Bestim- mung der Konzentrationen von Triphenylphosphin (TPP) und anderen Verbindungen, die in eine durch einen Molybd/inkomplex katalysierte Sauerstofftransferreaktion einbezogen sind. Gute Ergebnisse erzielte man mit einer einfachen Octadecylsilan-S/iule und einer mobilen Phase aus w/il3rigem Acetonitril (65%), und zwar fiir TPP, Pyridin und deren beide Oxide in Konzentrationen in der mobilen Phase von 0,0012 bis 0,12 g/ml. Keine Ausf/illungen von TPP treten auf w/ihrend der Analyse auch yon iibers/ittigten L6sungen mit bis zu 0,27 g/ml TPP. Einige zu beobachtende Besonderheiten werden diskutiert. - Anal. Lett. 22, 2637-2651 (1989). Dept. Chem., Florida Atlantic Univ., Boca Raton, FL (USA) W. Czysz

Titration of anionic surfactants using a new potentiometric sensor. Lj. Zelenka, M. Sak-Bosnar, N. Marek and B. Kovacs.

Verff. entwickeln eine ionenselektive Elektrode zur Bestimmung anio- nischer Tenside. Zu diesem Zweck iiberziehen sie eine Ruzicka-Selek- trode (J. Ruzicka et al: Anal. Chim. Acta 62, 15 (1972)) mit plastifizier- tern (Triskresylphosphat) Polyvinylchlorid, in das Hyamin-dodecylsulfat als aktives Elektrodensubstrat eingearbeitet worden war. Diese Elek- trode hat einen Arbeitsbereich von 10 2bis 10 6 M Dodecylsulfat. Sie eignet sich fiir potentiometrische Titrationen mit einer Richtigkeit von 0,3%. Der EinfluB verschiedener organischer und anorganischer Anio- nen wurde untersucht; die entsprechenden Selektivitfitskoeffizienten werden angegeben: Dodecansulfat 0,042; Dodecylbenzolsulfonat 2,17; p-Toluolsulfat 0,029; Nitrat 0,037; Chlorid 0,021 ; Sulfat 0,58. - Anal. Lett. 22, 2791-2802 (1989). Dept. Chem., Pedagog. Fac., Univ., Osijek (YU) W. Czysz

Rapid colorimetric determination of activity of subtilisin enzymes in cleaning products. A.E. Klein, J. Freiberg, S. Same and M.A. Carroll.

A new colorimetric method is described for the determination of enzymatic activity of subtilisin in cleaning products. The procedure is more rapid and precise than the casein digestion methods commonly used to assay protease activity. The principle of the colorimetric method depends on the determination rate ofp-nitrophenol released on hydrolysis of N-CBZ-L-leucine-p-nitrophenyl ester at pH 8.0 by subtilisin, with correction for any nonenzymatic (spontaneous) hydrolysis of the substrate. Because of the broad range of hydrolytic activity of this enzyme, and the difficulties in predicting its proteolytic activity, this hydrolytic rate was chosen as a general indicator of subtilisin enzyme behavior. The slope for 7 replicate standard curves generated over a 6 week period exhibited a relative standard deviation of 7.5%, and 8.0% for 20 replicates with an enzyme cleaning product. Papain does not interfere with this assay. - J. Assoc. Oft'. Anal. Chem. 72, 881-882 (1989). Bausch & Lomb Inc., Personal Products Div., Rochester, NY (USA)

Calculation of plasticizers' retention indices in programmed temperature gas chromatography using a non-linear interpolation. F. Helaimia, M. Boumahraz, H. Sissaoui and D. Messadi.

The retention temperatures of standard n-alkanes obtained from a theoretical model which makes use of a transcendent integral do not vary linearly in terms of their carbon numbers. Natural cubic splines were used to compute retention indices of some plasticizers in linear programmed-temperature gas-solid and gas-liquid chromatography. By

comparing these values of retention indices to those obtained by linear interpolation it was found that: 1) the differences in values of the retention indices can reach ninety units; 2) the values of the retention indices obtained by cubic spline interpolation correspond better to linear distribution. - Analusist7, 596-600 (1989). Lab. Pollution, Univ. Annaba (Algeria)

2.3 Geological materials

Aufschlugverfahren in der analytiscben Geochemie (2). H. Heinrichs. Ausfiihrliche [Jbersichtsarbeit fiber Aufschlugmethoden yon Gestei-

hen, Erzen, Schlacken und B6den mittels Na3CO3, KOH, NazOz, (NazCO3+NazB407 oder H3BO3) bzw. (LizCO3+Li2B¢O7 oder H3BO3), LiBOz+LizB407, K2S207 oder KHSO4, NH4HSO4 + NH4NO3 und KHFz-Schmelzen. Die Einwaage, verwendete Tiegel, Auf- schlul3temperatur, L6sen der Schmelze, Verluste durch Verfliichtigung sowie m6gliche Riickst/inde werden mitgeteilt. -- LaborPraxis 14(1/2), 20-25 (1990). Geochem. Inst., Univ. G6ttingen (D) H. Hoffmann

Inductively coupled plasma/mass spectrometry in geochemistry. U. Sie- wers.

The use of a plasma mass spectrometer for quantitative analysis was demonstrated for the first time in Europe at an international geochemistry symposium in Helsinki in 1983. Geochemists have been waiting for such a sensitive analytical instrument for many years for various reasons: 1. The concentration of many elements in the earth's crust and in natural waters is often below the detection limits of conventional analytical techniques. Many of these elements are of great concern in terms of environmental pollution (e.g. Be, As, Se, Mo, Cd, Hg and T1). 2. It is necessary to preconcentrate elements before analysis for most other laboratory procedures (e.g. heavy metals in water, rare earth elements and gold). 3. Trace elements are becoming more and more important in the study of geochemical processes and mineral exploration. 4. The method offers the possibility of multi-element analysis with high sensitivity. The urgent need to reduce human interference in the complex chemistry of the biosphere is already painfully clear, e.g. forest decline, pollution of drinking water, rivers, lakes, or the North Sea. Several examples of the application of the method will be discussed which have been handled within a geological survey. The use of ICP-MS can help elucidate transport of elements and chemical processes in water of different sources, sediments, soils, and rocks by supplying precise analytical data. But there is still a need for reliable standard and reference materials with different matrices. - Mikrochim. Acta 1989, III, 365-372. Bundesanst. Geowiss. Rohstoffe, Hannover (D)

Application of high resolution ICP-spectrometry to the determination of B, Be, Co, Mo and Sn in soils and similar matrices. P. Schramel.

The most sensitive emission lines for the elements B, Be, Co and Mo are strongly influenced by disturbing emission lines of Fe using "normal" optical resolution. The advantages of high resolution, applying the new ICP-spectrometer JY 38 Plus (Jobin-Yvon, France) with the 2400 lines/ mm grating measuring in the 1 st and 2nd order will be discussed. Beside the concentrations in soils, sediments and sludges, applying aqua regia and HF decomposition methods, the detection limits in these matrices will be given. The possibilities of ICP-spectrometry for the determination of the above-mentioned elements are shown at the examples of SRMs (standard reference materials). For example, the most sensitive and normally used line for the determination of boron at 249.7733 nm cannot be used in case of this type of matrix due to normally high Fe-concentrations and due to a strong Fe-interference. Therefore, it is necessary to use the line at 249.6778 nm, where an interference-free measurement can be achieved in case of high optical resolution. The measured B- contents in these samples are in the range of 20 to 60 gg/g, for Co in the 10 gg/g region, for Be well below 1 gg/g, for Sn between 3 and 400

2.4 Environmental matrices 675

gg/g. Mo was only detectable in the sludge samples (limit of determination 0.5 gg/g). - Mikrochim. Acta 1989, III, 355 - 364. Ges. Strahlen- und Umweltforsch. mbH, Inst. Okol. Chem. Neuherberg (D)

Determination of total, leachable and mobile boron in sedimentary rocks by ICP-AES. G. Zeibig.

An ion exchange batch technique is described, which allows to determine the amount of mobile boron in geological material. Boron selective ion exchange resin IRA-743 (0.5 g, effective size 0.45 mm) was slurried together with 5 g sample (grain size smaller than 0.04 mm) at 70°C in aqueous solution. After separating resin and suspension by sieving, elution was done in columns with 3 N HC1. Boron was determined in the eluates by ICP-AES. Possible correction for the iron interferences on the boron emission lines are discussed. The mobile boron content in the investigated shallow marine sedimentary rocks ranged between 5 and 10% of the total. It must be assumed that most of the boron in the shales is fixed in the lattice of the minerals. - Mikrochim. Acta 1989, III, 3 8 9 - 397. Arbeitsgruppe Geochem., Hahn-Meitner-Inst. Berlin GmbH, Berlin (D)

Determination of trace metals in hydrothermal calcites by ICP-methods. J.H. Luck and V. Lfiders.

Lanthanum, cerium, and europium in calcites from carbonate-sulfde banded ores were determined by standard addition using ICP-MS. The concentration ranges in solution were for La 700-36 ng/g, Ce 2000-149 ng/g, and for Eu 140-2 .4 ng/g. Only Ce was determined by both ICP methods, and the results agree within 3 to 4%. In a second step, a scan over the mass range of the rare earth elements (REE) was performed. The solutions were analyzed directly without applying preconcentration or separation procedures. ICP-AES was used to determine Ca, Mn, and Fe. The matrix Ca is present in a concentration range from 1600 to 1300 gg/g and the major impurities Mn and Fe are 152-32 and 100-28 gg/g, respectively. The detection limits of ICP-MS for REE are found to be better by two orders of magnitude than for ICP-AES. A commercially available SCIEX Elan ICP-MS with additional software was used to make mathematical correction for isobaric interferences and molecular ions. - Mikrochim. Acta 1989, III, 329-336. Hahn-Meitner-Inst. Berlin GmbH, Berlin (D)

Rapid determination of seven trace elements in rock reference samples by ICP-MS. T. Okai.

The application of ICP-MS for the rapid and very sensitive determination of seven trace metals in silicate rock samples is investigated. The rock sample of 0.1 g was decomposed with HNO3-HC104-HF, then evaporated to dryness. The residue was dissolved in 2 ml HNO3 and made up to 100 ml with water. Since even small amounts of HC104 remaining could lower the determined values, complete evaporation of HC10~ was performed. In the determination of Ge, the use of HC1 for sample digestion lowered the values. Because our experiments showed that HC104 did not affect the Ge determination, it is likely that C1- ion exerts its effect on the Ge determination during the acid digestion process. It has been reported that both 5SFeO + and 58NIO + interfere with the determination of V~Ge. Also, the coexistence of ~ 14Sn interferes with the determination of 114Cd" However, in most cases of rock analysis, these kinds of interference are not significant. When such interference is observed, 76Ge and 11 ~Cd can be effectively used. Analytical results of ten GSJ rock reference samples using the simple and rapid method described above were in good agreement with reference values. - Bunseki Kagaku 39, T 5 5 - T 5 9 (1990) (Japanisch, mit engl. Zus.fass.). Geol. Survey Japan, Tsukuba-shi, Ibaraki (J)

Calibration of the ion microprobe for the quantitative determination of strontium, iron, manganese and magnesium in carbonate minerals. P.K. Swart.

The necessary operating conditions have been determined for the measurement of trace concentrations of Mg, Mn, Fe, and Sr in calcite and dolomite using a Cameca 3fion microprobe with the energy filtering method. With this technique, the presence of interference can be ascertained by examining the deviation of the measured isotopic ratios of an element from their natural values as a function of the kinetic energy

acquired during the sputtering process. With the energy filtering method it is possible, using an energy offset of - 5 0 V, to reduce interferences from other species at masses 24, 54, and 88 for Mg, Fe, and Sr. Although Mn has only one stable isotope, it is believed that a similar voltage offset may be suitable for this element. By use of these conditions, calibration lines have been established for Mg, Fe, Mn, and Sr employing 11 calcite and dolomite standards. It is estimated that for carbonate materials, concentrations of Mn, Mg, and Sr can be quantitatively measured as low as 1 ppm and Fe as low as l0 ppm. No significant differences in calibration were observed between calcite and dolomite. The slopes and intercepts of the relationships were found to remain constant within error over periods of 3 years. - Anal. Chem. 62, 722-728 (1990). RosenstieI School Marine Atmos. Sci., Univ., Miami, FL (USA)

Determination of thorium isotopes in bastnaesite ores. L. Doretti, D. Ferrara and G. Barison.

A procedure for the determination of alpha-emitting thorium isotopes in bastnaesite ores has been developed. The refractory sample was completely decomposed by potassium fluoride fusion in a platinum crucible followed by transposition to a pyrosulfate fusion. The pyrosulfate cake was dissolved in HC1 and the resulting precipitate dissolved in DTPA solution; thorium was coprecipitated as hydroxide using cerium present in bastnaesite as natural carrier. Thorium was then extracted into a TOPO solution, separated by using Dowex 1-X8 for anion exchange, electrodeposited and finally analyzed by alpha-spectrometry. Thorium was also determined spectrophotometrically using Arsenazo as a colorimetric reagent. The thorium yield of the above discussed chemical procedure is more than 85%. - J. Radioanal. Nucl. Chem., Art. 134, 3 4 3 - 352 (1989). Serv. Sicure Lavoro Protez. Sanita CNR, Padova (I)

2.4 Environmental matrices

Charcoal open tubular traps for the analysis of air and headspace samples. K. Grob, A. Artho, C. Frauenfelder and I. Roth.

5 cm x 0.3 mm i.d. glass capillary tubes coated with fine charcoal particles are used for the analysis of organic compounds, particularly tri- and tetrachloroethylene, benzene, and toluene, in air and headspace samples. Due to their small size, these traps are easy to use with capillary GC. As, e.g. 20 ml of gas can be sucked through this trap in 20 s, it is a simple technique providing high sensitivity; compared to headspace with split injection, sensitivity is increased by a factor exceeding 100. The column effluent is split into FID and ECD in such a way that small as well as large amounts of the chlorinated compounds can be detected. - J. High Resolut. Chromatogr. 13, 257-260 (1990). Kantonales Lab., Zfirich (CH)

Determination of ammonia/air diffusion coefficient using Nation lined tube. L.L. Spiller.

Spuren gasf6rmigen Ammoniaks kSnnen aus Luft entfernt werden, wenn man diese Luft dutch ein mit einem Nafionfilm ausgekleidetes Teflonrohr str6men lfil3t. Die Bedingungen der laminaren Luftffihrung und die Rohrdimensionen werden anhand eines Blockdiagramms beschrieben. Das Teflonrohr ist seinerseits in ein Rohr aus rostfreiem Stahl eingebettet. Nach AbschluB der Probenahme/Absorption unter kontrollierten Bedingungen wird der Nafionfilm abgetrennt, das Ammo- niak extrahiert und an einer Ammoniakgaselektrode bestimmt. Man ermittelte einen Ammoniak/Luft-Diffusionskoeffizienten von 0,288 _+_+ 0,012 cm 2 s ~ bei 1 atm und 25°C. Im Bereich 10--92% wurde keine Abhfingigkeit von der relativen Feuchtigkeit beobachtet. - Anal. Lett. 22, 2561--2573 (]989). 1221 Kingston Ridge Road, Cary, NC (USA)

W. Czysz

Spectrophotometric determination of nitrite (nitrogen dioxide). V. Raman and C.P. Sharma.


Acidified p-rosaniline hydrochloride diazotised with NO2 /NO2 and coupled with N-l-naphthylethylenediamine dihydrochloride produces a red violet dye ()~max 560 rim) suitable for spectrophotometry of NO2-/ NO2. Beer's law is obeyed from 0.04-0.40 ppm of NO2 - concentration. Interferences due to S 2- (4 gg); SO32- (25 pg) and Cu 2÷, Mn a+, Pb 2÷ and Cr 3 + (50 gg) are negligible. Addition of 0.5 ml of 0.1 N EDTA to NO2- solution eleminatess interference due to metal ions. The method is applied to determine NO2 in air after fixing it in alkaline Na3AsO3 soln. - Procedure. To an aliquot of NO2- soln. add 2 ml p-rosaniline hydrochloride (0.04% in 0.72 M HC1), shake and add 0.5 ml of the coupling agent (0.1%). Dil. to 50 ml. After 30 rain, measure the absorbance at 560 nm against a reagent blank. - J. Indian Chem. Soc. 66, 840-841 (1989). Nat. Physical Lab., New Delhi (IND) H.B. Singh

Continuous generation system for low-concentration gaseous nitrous acid. M. Taira and Y. Kanda.

A flow type generation system based on the reaction of sodium nitrite solution with sulfuric acid has been developed for parts per billion levels of nitrous acid. The reagent solutions are conitnuously pumped into a reaction vessel and drawn off to waste. A carrier gas is passed through a mixture of the reagent solutions in the vessel and continuously purges nitrous acid vapor from the mixture. Nitrous acid output of the generator is characterized by using a Na2CO3-impregnated filter and a chemiluminescent NOx monitor. A stable generation of nitrous acid of known concentration can readily be achieved by adjusting the concentration of sodium nitrite solution. - Anal. Chem. 62, 630-633 (•990). Nat. Lab. High Energy Physics, Oho, Tsukuba, Ibaraki-ken (J)

Einsatz der Ionenchromatographie zur Immissionsanalyse von SO2. P. Herger, G. Kapolka and G.W. Israel.

Das in der Abluft enthaltene SOz wird in einer beschriebenen Anrei- cherungsapparatur mittels H202 zu Sulfat oxidiert. In dieser so gewonnenen Probe wird der SOz-Gehalt als Sulfat mittels Ionenchromatographie in einem Ger/it der Fa. Dionex 2000i/sp durch Leitf/ihigkeitsmessung bestimmt. Die Nachweisgrenze liegt bei 3 gg/m 3. Die so ermittelten SO2- Werte werden mit der TCM-Methode nach VDI verglichen, im gesamten Konzentrationsbereich von 6 - 2200 gg/m 3 wird eine gute f]bereinstim- mung erzielt. Vorteile: Die gesammelten Proben sind fiber liingere Zeit haltbar, auch bei h6herer Temperatur, und es wird mit nichttoxischer Absorptionsl6sung gearbeitet. - Staub - Reinhalt. Luft 50, 13-15 (1990). TU Berlin (D) H. Hoffmann

schiedene DurchfluBraten, Luftvolumina, in Gegenwart anderer Verun- reinigungen einschlieglich photochemischer Oxidantien untersucht. Sic liegt fiber 0,95 ffir monofunktionelle Carbonyle, unges/ittigte Carbonyle und ~z-Dicarbonyle, Die Wiederfindungsrate nach Elution der Kartu- schen liegt ffir alle getesteten Carbonyle fiber 99 %. Die Nachweisgrenzen liegen yon 0,14-1,24 ppb bei Verwendung von 60 1 Luftproben. Die Genauigkeit wird mit _+ 5% angegeben, wenn mit Hydrazonstandards gearbeitet wird. Das Verfahren wird ffir Umweltuntersuchungen, z.B. der Luftverschmutzung in Museen und ffir andere Luftproben angewandt. - Intern. J. Environ. Anal. Chem. 38, 495-5•2 (1990). DGA Inc., Ventura, CA (USA) R.H.S.

A coated piezoelectric crystal sensor for the determination of 2,4-toluene diisocyanate in air. J.F. de Andrade, O. FatibelIo-Filho, A.A. Suleiman and G.G. Guilbault.

2,4-Toluoldiisocyanat (TDI) ist ein verbreitet verwendeter Grundstoff bei der Herstellung vieler organischer Produkte. Dementsprechend wich- tig ist ein Verfahren zu seinem Nachweis und zur quantitativen Bestim- mung in Luft. Verff. haben daffir einen Sensor auf der Grundlage eines piezoelektrischen Quarzkristalls entwickett. Der Sensor wird vorher mit einer L6sung yon Tetrakis(hydroxyethyl)ethylendiamin (THEED)/Di- thizon in Aceton fiberzogen. Die gfinstigste Zusammensetzung des Uber- zugs ist 30% THEED in Aceton/gesfittigte Dithizonl6sung in Aceton (1 : 3, v/v). Der Aufbau der Detektorzelle einschlieBlich der experimentellen Durchftihrung der Messungen wurde von den Verff. in einer frfiheren Arbeit beschrieben: O. Fatibello-Filho et al.: Anal. Chem. 61, 746 (1989); vgl. diese Z. 335, 429 (1989). Man erhfilt eine lineare Response- kurve im Bereich 3 - 2 4 ppb TDI. Der Sensor beh/ilt seine gleichblei- bende Empfindlichkeit, Reproduzierbarkeit und Regenerierbarkeit fiber wenigstens 2 Monate. SO2 verursacht eine nicht zu vernachlfissigende St6rung. - Anal. Lett. 22, 2601 - 2611 (1989). Dept. Chem., Univ., New Orleans, LA (USA) W. Czysz

Eine neue photometrische In-situ-MelMnrichtung zur Staubkonzentra- tionsmessung. D. Coe, W. Fabinski, F. Klein und M. Quirmbach.

Das Verfahren beruht auf dem Prinzip der Lichtschw/ichung beim Durchstrahlen einer partikelbeladenen Mel3strecke. Die Staubmessung erfolgt kontinuierlich fiber 2 h, dann wird auf den zweiten MeBkopf umgeschaltet. Ausffihrliche Beschreibung des Verfahrens, der Auswer- tung und der Vorteile gegenfiber der bisher fiblichen Ausffihrung. - Staub-Reinhalt. Luft 50, 47-52 (1990). H. Hoffmann

Formaldehyde quantitation in air samples by thiazolidine derivatization: factors affecting analysis. A. Yasuhara and T. Shibamoto.

A new method for the determination of trace levels of formaldehyde in air was developed and validated. The method is based on the reaction of formaldehyde with cysteamine to form thiazolidine. Air samples containing trace levels of formaldehyde were prepared from paraformaldehyde. The percent yield of formaldehyde from paraformaldehyde was 85.1 + 1.14%. Air samples were bubbled into an aqueous cysteamine trap. Thiazolidine formed from formaldehyde and cysteamine in the trap was determined by GC with a fused silica capillary column and a nitrogen-phosphorus detector (NPD). The lowest detection level for thiazolidine was 17.2 pg, equivalent to 5.80 pg formaldehyde. The recovery efficiency of trace gas phase formaldehyde in air was greater than 90%. Formaldehyde levels in ambient laboratory air were 48.9- 56.2 ppb (v/v). - J. Assoc. Off. Anal. Chem. 72, 899- 902 (1989). Dept. Environ. Toxicol., Univ., Davis, CA (USA)

Sampling of atmospheric carbonyls with small DNPH-coated C18 cartridges and liquid chromatography analysis with diode array detection. C.M. Druzik, D. Grosjean, A. van Neste and S.S. Parmar.

Zur Probennahme von Carbonylen aus Luft eignen sich DNPH-be- schichtete C18-Kartuschen, anschlieBend kann flfissigchromatogra- phisch mit Dioden-Array-Detektion nachgewiesen werden. Die Elution der Kartuschen wird mit Acetonitril durchgeffihrt und die flfissigchro- matographische Analyse erfolgt unter Verwendung einer C18-Schutz- s/iule und einer C18-S/iule bei 30°C mit einem Acetonitril/Wasser-Ge- misch (55: 45). Die Carbonylstruktur wird verifiziert durch Vergleich der Dioadearray-Scans der Probe mit den UV-VIS-Spektren (190- 600 nm) von 20 Carbonylhydrazonen. Die Probennahmeausbeute wird ffir ver-

Analysis of microgram amounts of particulate material by simultaneous multiwavelength AES. R.S. Pomeroy, J.D. Kolczynski, J.V. Sweedler and M.B. Denton.

A unique simultaneous emission spectrograph is utilized to perform qualitative and quantitative analysis on trace quantities of solid particulates. The AES system consists of a direct current plasma source and an echelle spectrograph with a charge injection device detector, enabling the system to simultaneously measure the wavelength range from 220 nm to 520 nm with 0.02 nm resolution at 300 nm. Monitoring all wavelengths simultaneously allows the qualitative and quantitative determination of most major and minor constituent in a trace quantity of sample with little prior knowledge about the sample. The ability to perform qualitative and quantitative analysis on particulates is demonstrated by evaluating NBS certified coal fly ash, as well as a sample taken from the respirator air filter at an acute care unit in a hospital. - Mikrochim. Acta 1989, III, 347-353. Dept. Chem., Univ., Tucson, AZ (USA)

Determination of stable isotope ratio of lead in air-borne particulate matter by ICP-MS. H. Mukai and Y. Ambe.

ICP-MS was applied to the measurement of stable isotope ratios of lead, which are used as an indicator of the source of lead in airborne particulate matter. For the measurement of lead isotopes ratios, the influences of machine conditions, lead concentration and matrix elements to the precision and accuracy of the measurements were studied. At a scanning mode, dwell time of 40 ~ 160 ps gave the best precision to the isotope ratio measurements; about 0.3% of R.S.D. for z°6Pb/ 2°VPb and 2°6pb/z°SPb, 0.6% for z°6pb/2°4pb. Precision of the measurement was better at a high concentration of lead in sample solution.

2.4 Environmental matrices 677

The observed value of 2°6pb/z°7pb ratio was not affected by the lead concentration, but in the cases of 2°6pb/2°4pb and 2°6pb/z°SPb, about 1% of the value changed in the observed ratios with the lead concentration of 100~ 500 gg/1. Six matrix elements (Na, K, Ca, Mg, A1, Fe) did not affect the observed isotope ratios up to 200 rag/1. The lead isotope ratios of reference materials were measured by using two kinds of sample; crude sample and lead-isolated sample from matrix elements by anodic deposition. Both cases gave the same isotope ratio values, therefore, lead isotope ratios in airborne particulate samples can be measured by ICP- MS without any separation of lead from matrix elements. - Bunseki Kagaku 39, 177-182 (1990) (Japanisch, mit engl. Zus.fass.). Nat. Inst. Environ. Studies, Tsukuba-shi, Ibaraki (J)

Determination of lead in environmental samples by stripping voltammetry. L.I. Fedorina, A.P. Rysev, V.A. Solomonov, L.M. Kurtynina and L.P. Zhitenko.

Zur Bestimmung yon Pb(II) in Umweltobjekten (atmosph/irische Nie- derschl/ige, Naturwasser, Luft) wurde ein inversions-voltammetrisches Verfahren unter Anwendung der Quecksilberfilmelektrode (QFE) auf Kohlesitalunterlage ausgearbeitet. Als Bezugselektrode verwendete man Ag/AgC1 und als Hilfselektrode eine Kohlesitalelektrode. Auf diese Weise wurde Pb(II) mit der Nachweisgrenze 1 gg/1 (5 x 10 lo tool/l) und sr = 0,15 bestimmt. Arbeitsweise. QFE-Herstellung: Die rotierende Kohlesitalunterlage wird durch kurze Ber/ihrung (15- 30 s) mit einem Graphitstfibchen mit einer dtinnen Graphitschicht bedeckt und in die Hg(II)-L6sung (0,1 g/l), aus 02 durch N2 verdrS.ngt wurde, eingetaucht: 10 rain elektrolytische Hg-Ausscheidung auf ihrer Oberti/iche wird bei -0 ,8 V durchgeffihrt. Nach 40 s wird das Potential auf -0 ,8 bis -1 ,0 V eingestellt, QFE bei diesem Potential 1 - 2 min moditiziert und danach mit Wasser nachgewaschen. Bei der Analyse yon Naturw/issern benutzt man 10-15 ml Probe, bei atmosphfirischen Niederschl~igen werden 0,05- 0,5 ml Probel6sung mit HC1 auf die Endkonzentration 0,05- 0,2 mol/1 anges~tuert und die Pb-Ausscheidung auf QFE wird durch 2 - 5 min Elektrolyse der O2-freien L6sung bei -0,95 V durchgef/ihrt. Da- nach wird das anodische Wechselstrom-Voltamperogramm (10 mV/s) aufgenommen. Der Pb(II)-Gehalt in der Probe wird mittels Standardzu- satzmethode ermittelt. - Zh. Anal. Khim. 44, 2088-2090 (1989) (Rus- sisch, mit engl. Zus.fass.). Lomonosov Inst. feinchem. Technol., Moskau (SU) F. Jancik

Sampling device for a simple, fast calibration technique in gas chromatographic trace analysis of gas phases and vapor phases. H. Hachenberg.

In order to accomodate continually changing tasks in the [p~l/1]-[ni/ m3]ranges of gas chromatographic trace analysis of gas phases and vapor phases, a simple and time-saving calibration technique is presented which renders unnecessary conventional test mixtures of the above-mentioned concentration ranges. This new method is based on the simulation of such mixtures at the inlet of the GC unit with the aid of commercially available multiway sampling valves of various volumes by means of partial pressure sampling. - J. High Resolut. Chromatogr. 12, 742- 748 (1989). Hoechst AG, Frankfurt/M (D)

Amperometric monitoring of ozone in gaseous media by gold electrodes supported on ion exchange membranes (solid polymer electrolytes). G. Schiavon, G. Zotti, G. Bontempelli, G. Farnia and G. Sandon/t.

An in situ amperometric sensor suitable for monitoring ozone in gaseous media is described. It consists of a porous gold working electrode (contacting the gaseous sample) supported on one surface of an ion exchange membrane (Nation 417) which serves as a solid polymer electrolyte. The other side of this membrane faces an internal electrolyte solution (1 M aqueous perchloric acid) containing the counter and reference electrodes. Amperometric measurements are performed at an applied potential of 0.5 V vs. SCE, by inserting the sensor in a cell in which ozone-oxygen streams are fed with different controlled rates. A current sensitivity of 38 A M - 1 cm- 2 and a response time of 0.5 s are observed. The dynamic range turns out to extend up to 2 x 10 _3 M (4.48 x 10 .2 arm) with good linearity and a detection limit of 10- s M (2.24 x 10- 7 atm) is predicted for S/N = 3. These performances are compared with those provided by the corresponding gaspermeation membrane electrodes and by spectrophotometric methods employing suitable reagents.

The effect of the flow rate on current responses is also discussed. - Anal. Chem. 62, 293-298 (1990). CNR-IPELP, Padova (I)

Diffusionssammler zur Probenahme yon organischen gas- und dampffiirmi- gen Substanzen in Abgasen. A. Canela, U. Gruntz, H. Mfihleisen und S. Tanner.

Es wird ein Diffusionssammler aus Glas zum Anreichern organischer L6sungsmittel wie Methanol, Aceton, Ethanol und IsopropanoI in Ab- luft ausfiihrlich beschrieben. In diesen Sammler k6nnen bis zu vier Sorbentienr6hrchen, gef/illt mit Silicagel, Aktivkohle und Carbosieve S- II angebracht werden, diese nehmen dann die L6sungsmittel auf. Die beladenen Sorbentien werden anschliel3end in Glasfl~ischchen tiberfiihrt und mit PTFE-Septa luftdicht verschlossen, sie sind so l~ingere Zeit, bis zu 3 Monate, haltbar. Danach werden die gesammelten Komponenten desorbiert und mittels Capillar-GC mit FID, ECD, NPD und MS- Detektoren analysiert. Die untere Bestimmungsgrenze liegt bei 0,1 rag/ m 3. Es werden die Ergebnisse mit Testgemischen und yon Feldversuchen mitgeteilt. - Staub-Reinhalt. Luft 50, 7 - I 2 (1990). H. Hoffmann

Automatic off]on-line preconcentration for ICP-OES: Powerful instrumentation for water analysis. N. Prakash, G. Csanfidy, M.R.A. Michaelis and G. Knapp.

Automated preconcentration technique for off/on-line determination with ICP-OES have been developed for various metal ions of environmental interest. Preconcentration studies were performed on two different types of chemically bonded chelating ion-exchangers, namely EDTrA-cellulose(iminoacetate groups) and HSO3 • oxine-cellulose. En- richment studies were carried out at various preconcentration factors and also at different loadings. - Mikrochim. Acta 1989, III, 257-265. Dept. Anal. Chem., M!cro- and Radiochem., Univ. Technol., Graz (A)

Reagentless-continuous determination of aqueous ozone with glass tube separator-thin film semiconductor. T. Aoki and H. Oguro.

Verff. beschreiben ein Verfahren zur Bestimmung yon Ultra-Spuren Ozon in W/issern ohne Verwendung eines Reagens. Sie konstruieren eine Apparatur, die aus einem 30 ° geneigten Pyrexglasrohr besteht, an deren innerer Wandung die Probe abw/irts flieBt. In der Gegenrichtung str6mt vorher durch Silicagel und Aktivkohle gereinigte Luft, die das Ozon aus der wfil3rigen Probe aufnimmt und aus dem Separatorrohr kontinuierlich in einen Halbleiter-Detektor (n-Typ, In203) iiberfiihrt. Die Spannungs- /inderung an der Indiumoxidschicht gibt das MaB ftir die Ozonkonzen- tration der Luft bzw. der Probe oberhalb 5 ppb. Die Nachweisgrenze (S/ N = 3) liegt bei 0,02 ppt mit einer rel. Standardabweichung yon 3,8% bei 7,6 ppb 03. St6rungen durch H202, Mono- und Dichloramin treten nicht auf. - Anal. Lett. 22, 2871-2876 (1989). Lab. Environ. Chem., Coll. Engin., Univ. Osaka Prefecture, Mozu-umemachi, Sakai (J)

W. Czysz

On-line preconcentration and ICP determination for trace metal analysis. V. Porta, C. Sarzanini and E. Mentasti.

The use of a closed-loop on-line enrichment procedure in combination with an ICP plasma emission spectrometer has been developed for the analysis of trace metal ions, such as Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The procedure utilizes a preconcentration column tilled with an anion exchange resin and 8-hydroxy-7-iodoquinoline-5-sulfonic acid is added to the sample prior to preconcentration. Details on the optimization of pretreatment and instrumental conditions are described. Results obtained for the analysis of river water and antartic seawater are reported. - Mikrochim. Acta 1989, III, 247-255. Dipt. Chim. Anal., Torino (I)

Multielement trace metal determination by electrodeposition, scanning electron microscopic X-ray fluorescence, and inductively coupled plasma mass spectrometry. N.-S. Chong, M.L. Norton and J.L. Anderson.

Multielement analysis of multicomponent metallic electrode-posits is described, based on scanning electron microscopy with energy dispersive X-ray fluorescence [EDXRF] detection, followed by dissolution and inductively coupled plasma mass spectrometry [ICP-MS] detection. Ap- plication of the method is described for determination of trace elements in seawater, including Zn, Mn, Co, Cu, Cr, Ni, Fe, Cd, Pb, and Hg.


These elements are simultaneously electrodeposited onto a niobium wire working electrode at 1.40 V vs an Ag/AgC1 reference and subjected to EDXRF analysis. Internal standardization is practical for quantitative calibration at the i ppm analyte concentration level in an analyte:internal standard concentration ratio range of 0.02- 50. Detec- tion limits for EDXRF range from 1.9 ppb for Fe to 50 ppb for Cd. The deposit is dissolved for subsequent ICP-MS determination. Significant reduction in ICP-MS matrix interferences by Na, Ca, Mg, K, and C1 ions is achieved by deposition at potentials more positive than their very negative reduction potentials. Measurement of elemental isotope ratios is achieved with 0 - 8 % relative error. ICP-MS detection limits for all elements except Zn and Fe are superior to those of EDXRF. Mn, Ni, Cd, Pb, and Hg can easily be determined in the range of 13-86 parts per trillion with ICP-MS. - Anal. Chem. 62, 1043 - 1050 (1990). Dept. Chem., Univ., Athens, GA (USA)

Coprecipitation of trace metals by D N A and RNA molecules. K. Fujiwara, R. Kojyo, K. Okada and Y. Kodama.

Coprecipitation of trace metal ions in the aqueous sample was investigated by using several nucleic acids (DNA and RNA) as the carrier. After the pH of the solution containing metal ion was adjusted, DNA or RNA dissolved in NaOH solution was added. Precipitation of DNA (or RNA) was done by the salting-out method, adding sodium chloride and acetone to the DNA-metal solution. Coprecipitation efficiencies for most positive metal ions were found to be maximum at pH 2 3 when sodium hydroxide/acetate buffer was used. Negative ions such as Cr2072-, Mo70246 , and PtC162- were not precipitated with DNA in the pH range from I to 12. It is also found that coprecipitations of cobalt(III) complexes were dominated by their charge, i.e., the complexes having plus three charge are coprecipitated with DNA at the high rate but the complexes of zero or minus charge are not. The anticancer drug cis-platin is negligibly coprecipitated with DNA. The present coprecipitation method also allows the preconcentration of trace metal ions except iron, calcium, and magnesium, which were intrinsically contained in DNA and RNA at the appreciable concentration. - Anal. Chem. 62, 504-508 (1990). Fac. Integr. Arts Sci., Univ., Hiroshima (J)

Determination of nitrates in water using a new spectrophotometric method. L. Cherian and V.K. Gupta.

NO3-, after its reduction to NO2-, is used to diazotise p-aminoacetophenone for subsequent coupling with N-(1-naphthyl)- ethylenediamine to form a purple dye for spectrophofometry of NO3 -. The dye shows )~max at 545 nm (g = 5.73 × 104) and obeys Beer's law from 0.1 - 0.8 ppm of NO 3 - concentration. In determination of 0.4 ppm NO3 , the following species (in ppm) can co-exist: SO4 z (800); CN , PO~ 3- (200); F - , Br-, Li +, Be z+, Sb 3+, Bi 3+, Se 4+ (100); aniline (96); Sr 2+ (72); Ca 2+, Sn 2+, Pb 2÷, Mn 2+ (50); Ni 2+, Cd 2+, HCHO (48); Fe 3+, phenol (40); Cr 6+ (16) and Cu 2÷ (10). The method is used to determine NO3- in water samples. Procedure. To an aliquot of water sample add 5 mI of 1.2% ammonia soln., 1 ml of 1% MnC12 soln., 0.2 g Zn dust and shake. Filter after 5 rain. Add i ml of p- aminoacetophenone (1% in 20% HCI) followed by 6 M HC1 (to maintain pH 2 - 3) and 2 ml of 0.1% coupling agent. Dil. to 25 ml and measure the absorbance at 545 nm against a reagent blank. - J. Indian Chem. Soc. 66, 897-898 (1989). Dept. Chem., Ravishankar Univ., Raipur (IND) H.B. Singh

The determination of trace amounts of phosphate in natural waters by flow- injection fiuorometry. Wei Fusheng, Wu Zhongxiang and Ten Enjiang.

Zur Bestimmung yon Spuren Phosphat in nat/irlichen Wfissern wird ein Fliel3injektionsverfahren (FIA) mit fluorimetrischer Detektion beschrieben. Grundprinzip ist die Beobachtung, dab (aus dem Phosphat mit Ammoniummolybdat gebildetes) Molybdophosphat die Fluorescenz von Rhodamin 6G unterdriickt, und zwar proportional der Phosphat- konzentration. Die Fluorescenz wird bei 350 nm angeregt und bei 550 nm gemessen. Die Eichkurve ist aufwiirts linear bis 100 ng P/ml bei einer Nachweisgrenze yon 1,9 ng/ml. Die Wiederfindungen in natiirlichen W~issern betrugen 92 102%. Probendurchsatz: 120/h. - Anal. Lett. 22, 3081-3090 (1989). China Nat. Environ. Monit. Centre, Beijing (RC) W. Czysz

Determination of low level sulfde in environmental waters by automated gas dialysis]methylene blue colorimetry. D. Francom, L.R. Goodwin and F.P. Dieken.

Zur Bestimmung geringer Konzentrationen Sulfid in Umweltwasser- proben wird ein automatisiertes Gasdialyseverfahren mit anschliel3ender Methylenblau-Photometrie beschrieben. Erfal3t wird das in saurem Mi- lieu extrahierbare Sulfid, das aus der Probenmatrix durch eine Gasdialy- semembran abgeschieden und in einem Strom yon verdiinnter NaOH- L6sung aufgenommen wird. Diesen Sulfid-Rezeptorstrom versetzt man mit N,N-Dimethyl-p-phenylendiamin und Fe(III)-chlorid; das sich bil- dende Methylenblau wird bei 660 nm gemessen. Die Ergebnisse der Bestimmung in Standardl6sungen und ungetrfibten Umweltwasserpro- ben stimmen gut untereinander und mit den Ergebnissen nach der Stan- dard-Methylenblaumethode /iberein. St6rungen wurden insbesondere bei Anwesenheit von Cu(II)-Ionen festgestellt. Um zuverl/issige Werte zu erhalten, ist es notwendig, Ascorbins/iure als Antioxidans zuzugeben. Die Nachweisgrenze wird mit 2 gg/1 Sulfid angegeben. - A n a l . Lett. 22, 2587-2600 (1989). Alberta Environmental Centre, Vegreville, Alberta (CDN) W. Czysz

A selenium speciation model for the studies of natural water. L. Cam- panella, T. Ferri and R. Morabito.

Ffir die biologische Bedeutung von Selen ist neben der Konzentration noch die chemische Bindungsform wesentlich. Die Verff. empfehlen daher fiir eine Selenspezifizierung in natiirlichen Wfissern auf Se(IV)-Basis eine polarographische und eine invers-voltammetrische Bestimmungs- methode. Arbeitsweise. 100 gl einer 20 ppm enthaltenden Se(VI)-L6sung werden mit 2,7 m130%ig. HC1 und 1,5 ml deionisiertem Wasser gekocht. Nach Reduktion, Kfihlung und Volumeneinstellung auf 25 ml wird die Probe quantitativ in den Polarographen iiberffihrt. Als Reduktionszeiten wurden 5 bis 30 min unter Riickflug getestet. Organisch gebundenes Selen wird in stark saurer L6sung (6 M HC1) unter Rfickflul3 bei 80°C in 5 h aufgeschlossen, aufein Volumen von 25 ml eingestellt und kathodisch polarographiert. Die Methode wurde auch mit Tiberwasser-Proben getestet. Daneben wurden Fragen der Konservierung in Probengef553en aus unterschiedlichem Material und der Mineralisierung untersucht. Es wurden Wiederfindungsraten von 97.2 bzw. 102% fiir Proben mit deionisiertem Wasser bzw. Leitungswasser festgestellt, wobei je 40 ppb Se von jeder Selenverbindung vorgegeben waren. - Analusis 17, 507-513 (1989). Dept. Chem., Univ., Roma (I) Th. Kempf

New type of device for isolation of volatile organic compounds from aqueous samples based on generation of water-gas mixtures. M. Biziuk and J. Namie~nik.

The presented new design of a device for both continuous and periodic isolation of volatile organics from water is based on the following operating principle. A stream of carrier gas enters through a capillary vertical tube placed in the thermostated analyzed solution (periodic mode) or is fed through a side connection with a capillary ending to a vertical, thermostated tube which is constantly fed with a stream of analyzed aqueous sample (continuous mode). A gas-water mixture of highly developed surface is formed as a result. A spontaneous separation of aqueous and gaseous phases occurs at the outlet of the tube, the latter phase being subsequently analyzed for the presence of volatile organics. - Analusis 17, 587-591 (1989). Inst. Inorg. Chem. Technol., Techn. Univ. Gdansk (PL)

New spray reagents for the detection of hazardous phenols separated by TLC. S. Laskar, B. Sengupta and J. Das.

Orthanilic acid, o-dianisidine and their diazotised products are used for rapid and efficient detection of 22 phenols on silica gel-G TLC plates using chloroform/methanol (98:2) as developer. Phenols (phenol; ~-/[3- naphthol; o-/m-/p-cresol; o-/p-aminophenol; catechol; thymol; p-phenylphenol; 2,3-/2,4-/2,5-xylenol; o-/p-chlorophenol; 2,4-dichloro- phenol; 2,4,6-trichlorophenol; o-/p-nitrophenol; 2,4-dinitrophenol; 4- chloro-m-cresol) give easily detectable characteristic colours and the detection limit is generally 1 - 5 gg, and even as low as 0.1-0.5 gg in most cases for the diazotised orthanilic acid. The diazotised products are useful for the detection of most of the phenols in polluted river waters or industrial effluents. - J. Indian Chem. Soc. 66, 899-901 (1989). Dept. Chem., Univ. Burdwan (IND) H.B. Singh

2.5 Soils, plants and agricultural-technical products 679

Spectrophotometric determination of phenol in waste water present at triarylphosphates manufacturing. W. Herzog.

A method of fast determination of phenol content in waste water in the presence of triarylphosphates was presented. Phenol was determined as phenolate (absorption max. at 288 nm) in ammonia water medium. The analyzed waste water neutralized with a 0.5 mo1-1-1 HC1 to pH ~< 7 and diluted to a concentration equal to that of the measured solution was used as a reference material. Under the analytical conditions (pH of the solution changed) change of position and of absorption intensity of triarylphosphate band (~ = 275 rim) were not observed, which allows its compensation. The influence of inorganic compounds was eliminated using the absorbance difference A = A288 - A320 [nm]. The precision of the method was estimated. - Chem. Analit. 34, 253-259 (1989) (Polnisch, mit engl. Zus.fass.). Inst. Heavy Organ. Synth. "Blachownia", Kedzierzyn-Kozle (PL)

Liquid desorption of organic solvents from industrial sludges. L. Ceccon, A. Turello, G. Mocellin and L. Colugnati.

Analysis of organic solvent residues in industrial sludges is usually based on preliminary extraction of solvents from the matrix, followed by GC determination. Liquid desorption with carbon disulfide is one of the most frequently used methods of recovery. Because of the number of parameters that can affect desorption efficiencies, we evaluated recoveries from 2 wastes with different physicochemical characteristics. Results were similar for both matrixes. The study of the kinetics of recovery showed that equilibrium was reached within about 5 rain. On the other hand, specific adsorption phenomena were observed not only for strongly polar solvents even at the highest concentrations, but alo for weakly polar compounds at the lowest concentrations. Water content of the matrix had little effect on recovery of the solvents examined, except for 2-ethoxyethanol, which yielded notably lower extractions when the moisture content of the matrix increased. - J. Assoc. Off. Anal. Chem. 72, 1010-1014 (1989). Dipt. Econom. Merceol., Univ., Trieste (I)

Chemical derivatization analysis of phenols. Part VI. Determination of chlorinated phenolics in pulp and paper effluents. H.-B. Lee, R.L. Hong- You and P.J.A. Fowlie.

Based on the in-situ acetylation procedure, a method for the determination of 31 chlorinated phenols, guaiacols, catechols, syringols, and vanillins in pulp and paper effluent samples has been successfully developed. Except for 4-chlorocatechol, this procedure provided satisfactory recovery for all phenols at 3 levels of fortification, namely, 400, 40, and 4 lzg/1. The acetyl derivatives were analyzed by GC using a 30 m DB-5 capillary column interfaced to an electron-capture detector. Mass spectral abundance data for the characteristic ions of the acetyl derivatives were used for confirmation of compound identities. By operating a mass selective detector in the selected ion monitoring mode, this procedure was further extended to the monochlorinated phenolics. Using a 50 ml effluent sample, the method detection limit was 0.5 btg/1 for all except the monochlorinated compounds, which had a detection limit of i gg/1. Several effluent samples from a Canadian paper mill were analyzed by this procedure and the results are presented. - J. Assoc. Off. Anal. Chem. 72, 979-984 (1989). Nat. Water Res. Inst., Res. Applic. Branch, Burlington, Ontario (CDN)

Fluorometrie in der Umweltanalytik. J. Behnert, H. Ilchmann and K.-P. Raezke.

In der Umwelt gibt es nur relativ wenig natfirlich vorkommende fluorescierende Substanzen, weswegen der MatrixeinfluB bei der Fluorome- trie sehr gering ist. Daher eignet sich diese Methode besonders zum Nachweis yon Umweltchemikalien. Die Anwendbarkeit und zuk/inftige Entwicklungen werden beschrieben. Labor-Praxis 13, 1116-1120 (i989). GAT Gamma Analysentechnik GmbH, Bremerhaven (D)

M. Rittich

Rapid screening of polycyclic aromatic hydrocarbons and fingerprinting of environmental materials by laser-excited fluorescence spectrometry. A. Mellone, B.W. Smith and J.D. Winefordner.

Laserangeregte Fluorescenz von molekularem Dampf organischer Verbindungen in einem Graphitrohrofen wird zum schnellen Screening

ffir polycyclische aromatische Kohlenwasserstoffe (PAK) in verschiedenen Probenmatrices eingesetzt. Desgleichen als eine Art Fingerprintme- thode zur Charakterisierung von Erd61, Erd61produkten und/ihnlichen Substraten. Die Einfachheit und Schnelligkeit dieses Verfahrens empfehlen es ffir schnelle Kontrollen auf Anwesenheit von PAK. - Talanta 37, 111-118 (1990). Dept. Chem., State Univ., Gainesville, FL (USA)

W. Czysz

Use of carbon-13 labelled dioxins mixture for analysis of polychlorinated dibenzo-p-dioxins in environmental samples by GC/MS. K.P, Naikwadi and F.W. Karasek.

Polychlorierte Dibenzo-p-dioxine (PCDDs) k6nnen in komplizierten Umweltproben bestimmt werden, wenn man ein C-13 markiertes Dioxin- gemisch verwendet und markierte und unmarkierte Dioxine in GC/MS Arbeitsweise mit EI-SIM-Auswertung mil3t. Die quantitative Auswer- tung kann mit Hilfe eines Vergleichstandard-Gemisches mit C-13 mar- kierten Dioxinen durchgeffihrt werden. Der C-13 Dioxinstandard ist ffir die Ermittlung eines Retentionsfensters f/ir Tetra- bis Octa-Chlordioxine, zur Identifizierung der Dioxine in jeder Gruppe und Berechnung der Wiederfindungsrate der Dioxine in Proben, die intensive Probenreini- gung vor der GC/MS-Analyse erfordern, sehr gut einzusetzen. Hier wird das Verfahren auf die Analyse von Flugasche angewandt, die im Soxhlet mit Benzol extrahiert wird. - Intern. J. Environ. Anal. Chem., 38, 329 - 342 (1990). Dept. Chem., Univ., Waterloo, Ontario (CDN) R.H.S.

The ICP-MS approach to environmental studies. D. Beauchemin. The certification of marine materials for trace metals is a process

which challenges every technique involved, especially if a technique is as recent as inductively coupled plasma mass spectrometry (ICP-MS). Developmental work was required for several materials (natural waters, biological materials, marine sediments). It is reviewed here, in an attempt to show how one can take full advantage of ICP-MS. This includes a review of the digestion procedures developed for the multielement analysis of biological materials and marine sediments in order to minimize spectroscopic interferences. The multielement analysis of natural waters is also reviewed, in particular that of saline waters which requires a separation of the analytes from the alkali and alkaline earths elements and a preconcentration of the analytes on a column of silica-immobilized 8-hydroxyquinoline. The potential of performing this separation/preconcentration procedure on-line is showed using both published and original results. Finally, the application of ICP-MS to speciation is illustrated by the determination of methylmercury in biological materials after extraction, and by the determination of arsenic species by high-performance liquid chromatography coupled to ICP-MS. - Mikrochim. Acta 1989, IIl, 273-281. Dept. Chem., Queen's Univ., Kingston, Ontario (CDN)

2.5 Soils, plants and agricultural-technical products

Determination of forms of sulfur in plant material by X-ray fluorescence spectrometry. A. Pinkerton, K. Norrish and P.J. Randall.

Ein Verfahren zur Bestimmung v o n S 6 + (Sulfat) und S c (C-S-gebunde- nem Schwefel) in Pflanzen durch R6ntgenfluorescenzspektrometrie wird beschrieben, welches wesentlich einfacher und schneller als die chemische Bestimmung der entsprechenden Schwefelformen ist. Das Verfahren beruht darauf, dab sowohl die Kc~- als auch die K[3-Linien wellenl~ingenab- hS.ngig vonder chemischen Bindung und damit im wesentlichen vonder Oxidationszahl sind. Die S Ks-Peak-Shifts im Verh/iltnis zur Oxidations- zahl sind f/it eine Reihe von in Pflanzen vorkommenden Sulfaten wie auch Verbindungen mit C-S-Bindung tabelliert. Durch Markierung von Pflanzenmaterial mit (NH4)2SO4 und Methionin wird gezeigt, dab eine quantitative Wiederfindungsrate mit dem R6ntgenfluorescenzverfahren erreicht wird. Die Methode wird ffir die Bestimmung von Schwefelver- bindungen in landwirtschaftlichen Produkten empfohlen. - X-Ray


Spectrom. 19, 63-65 (1990). CSIRO Div. Plant Ind., Canberra, ACT (AUS) R.H.S.

XRS-Analysis of sulfides by fusion methods. K. Norrish and G.M. Thompson.

Ein Verfahren zur XRS-Schmelzanalyse yon mineralischen und pflanzlichen Konzentraten, die Sulfide wie PbS, ZnS, CuFeS2 und FeS2 enthalten, zusammen mit Schlacken, Steinen, D/impfen und Kohlen wird beschrieben. Das Verfahren verwendet einen kurzen Voroxidations- schritt mit Natriumnitrat mit nachfolgender Schmelze mit einer geeigneten Hitzequelle. Ftir alle Elemente werden die K~-Linien verwendet mit Ausnahme fiir Sb (Lc 0, Pb (M~) und As (K[3). Die Verluste von Schwefel durch Verflfichtigung und von Metallen in Platintiegeln sind fiir die allgemeinen Bestimmungen akzeptierbar und zu vernachl/issigen. Das Verfahren gestattet die Bestimmung sowohl schwerer als auch leichter Elemente. Ergebnisse fiir eine Reihe von Proben werden mitgeteilt. - X-Ray Spectrom. 19, 67-71 (1990). CSIRO Div., Soils, Glen Osmond, SA (AUS) R.H.S.

amino acid on 3 ~tm and 5 gm octyldecylsilane RP-HPLC columns can be achieved within 15 and 30 min, respectively. Two prominent chromatographic peaks, observed with commercial preparations of A2bu, were also present in chromatograms of flatpea extracts. Quantifi- cation of A2bu in plant samples using peak areas from fluorescence and absorbance (A340 nm, A430 nm) chromatograms and their corresponding calibration curves gave similar results. Precision in peak area determinations for the more stable derivative was high (CV _< 5%), and sensitivity of the assay, based on this peak, was in the subnanomole range. The detection limit was 78 picomoles. S-J3-(4-pyridylethyl)penicillamine (Pep) was found to be a suitable internal standard. Calculation of A2bu concentrations using Azbu/Pep peak-area ratio calibration curves provided a reproducible means to quantify A2bu in flatpea extracts. Avail- ability of this analytical system will promote intensive investigations of the regulation of A2bu levels in flatpea tissues and the relationship between these levels and the health of animals that consume flatpea herbage. - J. Liquid Chromatogr. 12, 3033 -3050 0 989). USDA-ARS, Appalachian Soil Water Conserv., Res. Lab., Beckley, WV (USA)

Neutron activation method for nitrogen determination in biological specimens. L. Stoeva, TS. Pantaleev and A. Damyanova.

For the determination of the nitrogen content in plants, 14 MeV neutron activation analysis was used based on the determination of the elemental concentration by measuring the area of the gamma-radiation of the radionuclide 13N as a result of 14N(n,2n)lSN reaction. Three methods were tested in order to obtain quantitative results: comparator method, method for absolute determination of the neutron flux and monitor method. Using the monitor method, results for nitrogen content in plant species were obtained - for beans 74.8% and for maize 1.8%. The precision of determination is _+ 10%. The possible sources of errors are analyzed. The efficiency of the Ge(Li) detector has been determined using a combined T-source in the energy interval 120-1400 keV with precision of 4.5%. The sensitivity achieved was 4 mg or 47 imp/rag per rain. -- J. Radioanal. Nucl. Chem., Art. 134, 285-292 (1989). Inst. Nucl. Res. Nucl. Energy, Bulgarian Acad. Sci., Sofia (B)

Separation of some quaternary ammonium compounds from maize by OPLC. M. Garami and E. Mincsovics.

The importance of betaines in plant physiology has required their routine analysis. In addition to discussing betaine i$1entification by complicated and expensive methods, this paper describes the development of an overpressured-layer chromatographic method for some quaternary compounds expected in higher plants. The method utilizes a precleaning treatment for more sensitive quantitative measure. Previously reported problems concerning spot color sensitivity have been lessened. Choline, trigonelline, and glycinebetaine seem to appear in maize. The results presented provide groundwork showing OPLC to be a potential tool for monitoring quaternary ammonium compounds in plant tissues. - J. Planar Chromatogr. 2, 438-441 (1989). Lab. Instrument Co, Budapest (H)

Quantitative high-performance liquid chromatography and enzymatic estimation of four free amino acids in powders of anthers from bulbs of tulip. J. Tonecki, N. Gorin and W. Verhagen.

There was no significant difference between mean mass fractions of aspartic acid measured enzymatically and by HPLC. Thus aspartic acid was estimated specifically by the HPLC method. The bands of asparagine and glutamine (amino-amides) in the chromatograms originated from substances other than amino-amides, as the data from the HPLC procedure were significantly higher than the enzymatic data. Glutamic acid analyzed by HPLC was not affected by natural reducing substances of the anthers, as the data were significantly lower than the enzymatic data. Therefore HPLC estimation of glutamic acid was more selective than the enzymatic estimation. -- J. Liquid Chromatogr. 12, 2321-2331 (1989). Agric. Univ., Warsaw (PL)

High performance liquid chromatographic analysis of 2,4-diaminobutyric acid in flatpea extracts. J.G. Foster.

A rapid, reliable method for quantification of 2,4-diamino-butyric acid (A2bu) in flatpea (Lathyrus sylvestris L.) extracts has been developed. Resolution of ortho-phthalaldehyde derivatives of the basic

Determination of free and total gossypol by high-performance liquid chromatography. R.J. Hron, Sr., M.S. Kuk and G. Abraham.

Existierende HPLC-Verfahren gestatten nur die Bestimmung reinen Gossypols, w/ihrend die offizielle AOCS-Methode sowohl Gossypol als auch andere physiologisch aktive Gossypol-artige Verbindungen, die mit 3-Amino-l-propanol und Ani!in reagieren, bestimmt. Die Futtermittel- industrie setzt das offizielle AOCS-Verfahren ein, welches jedoch komplex ist und dessen Ergebnisse nur schlecht unter verschiedenen Labora- torien vergleichbar sind. Deshalb wird ein HPLC-Verfahren entwickelt, welches 3-Amino-l-propanol als komplexierendes Agens einsetzt und zur quantitativen Bestimmung yon freiem und Gesamt-Gossypol in Baumwollsamen, O1 und ethanolischen Micella einsetzbar ist. Es wird dazu auf einer C18 Reversed Phase S/iule mit einer austauschbaren C18 Supelguard Schutzs/iule gearbeitet, die isokratisch mit Methanol/Wasser (87:13) + 0,1% Phosphors~iure betrieben wird. Als komplexierendes Reagens wird 3-Amino-l-propanol in Eisessig zugesetzt, die L6sung abgekiihlt und mit N,N-Dimethylformamid verdtinnt: Der Nachweis wird bei 254 nm im UV ausgeffihrt. Dieses einfache, empfindliche Verfah- ren ergibt reproduzierbare Ergebnisse. - J. Am. Oil Chem. Soc. 67, 182-187 (1990). Southern Reg. Res. Center, Agricult. Res. Serv., USDA, New Orleans, LA (USA) R.H.S.

Rapid method for the clean-up of extracts of cottonseed prior to aflatoxin determination by bi-directional HPTLC. N. Bradburn, K. Jewers, B.D. Jones and I.I. Tomlins.

A non-polar phenyl-bonded-phase clean-up procedure has been developed for determining aflatoxin concentrations in aqueous acetone extracts of cottonseed by bi-directional HPTLC. It involves the addition of lead acetate solution to the extract prior to its passage through the bonded-phase cartridge. The accuracy and precision of the method have been evaluated for a range of aflatoxin concentration between 4 .7 - 806.1 p.g/kg (B1), 2.8--419.8 gg/kg (Bz), 5.1 --820.3 gg/kg (G1) and 3.3 - 396.9 gg/kg (G2). The coefficients of variation varied between 0.8 and 12%, with mean recoveries between 83 % and 99%. The limits of detection were found to be between 1.1 ~tg/kg (Bz and G2) and 2.7 gg/kg (B1). Comparison of the method with the first action AOAC method for cottonseed showed that the PH cartridge method recovered 80% more aflatoxin B~ and 52% more B2 from a sample naturally contaminated with aflatoxin. It was also more precise for aflatoxin B1 as well as being more rapid and cost effective. -- Chromatographia 28, 541 - 544 (1989). Overseas Dev. Nat. Resources Inst., Chatham Marit., Chatham, Kent (GB)

Selective determination of soluble inorganic selenium(IV), (VI) and organic selenium in soil. H. Yamada, T. Hattori, T. Miyamura, M. Okada and A. Ikeda.

Soil extracts containing appreciable amounts of dissolved organic compounds often present difficulties in their analysis for selenium. The addition of a small amount of copper ion to the soil extracts was found to be effective for suppressing interference caused by the organic compounds in the extracts. By applying this result, a method for the fractional determination of selenium in soil extracts was developed. Selenium(IV)

2.8 Pharmaceuticals and cosmetics 68]

was determined by HPLC with fluorescence detection after reaction with 2,3-diaminonaphthalene. Selenium(VI) was first reduced to the tetravalent state with potassium bromide and hydrochloric acid as reducing reagents and copper ion, then the total inorganic selenium was determined by the same method as the determination of selenium(IV). The amount of selenium(VI) was calculated by subtracting the amount of selenium(IV) from the total inorganic selenium. Total selenium in the soil extract was also determined by the same method as the total inorganic selenium after oxidizing the organic compounds in the extract. The amount of organically-bound selenium was estimated from the difference between the total selenium and the total inorganic selenium. The proposed method could be applied to the fractional determination of selenium in the soil extract with satisfactory reproducibility and recovery. - Bunseki Kagaku 39, 151-157 (1990) (Japanisch, mit engl. Zus.fass.). Fac. Agricult., Prefect. Univ., Kyoto (J)

Liquid chromatographic method for determination of extractable nitroaromatic and nitramine residues in soil. T.F. Jenkins, M.E. Walsh, P.W. Schumacher, P.H. Miyares, C.F. Bauer and C.L. Grant.

Air-dried soil samples are ground with a mortar and pestle and extracted with acetonitrile in an ultrasonic bath. A portion of extract is diluted with aqueous CaCI2 to flocculate suspended particles, filtered, and analyzed by LC. The method provides linear calibration curves over a wide range of concentration. Detection limits ranged from 0.03 to 1.27 gg/g. Recovery of spiked analyte was better than 80% for all analytes tested. Each step in the analytical procedure was optimized using spiked and field-contaminated soils. This optimization included test to (1) assess the effectiveness and kinetics associated with various extraction methods, solvents, and soil-to-solvent ratios; (2) compare separations achievable using various combinations of reverse-phase columns and eluants; (3) assess analyte recovery and ease for use for various procedures to remove particles from extracts; and (4) document stability of soil extracts and analytical stock and working standards. A ruggedness test and a preliminary assessment at 2 other laboratories indicated that the method was sufficiently rugged to justify a full-scale collaborative test. A comparison of extraction kinetics for spiked soil vs field-contaminated soil revealed very different kinetic behavior, indicating it is unwise to develop extraction procedures based solely on spiked soils. - J. Assoc. Off. Anal. Chem. 72, 890-899 (1989). U.S. Army Cold Reg. Res. Engin Lab., Hanover, NH (USA)

2.8 Pharmaceuticals and cosmetics

Drug screening and confirmation by thin-layer chromatography. A.K. Singh, K. Granley, M. Ashraf and U. Mishra.

Several studies have indicated that TLC has excellent resolution and, therefore, permits simultaneous identification of a wide range of substances in a single run. Applications of TLC methodology in drug testing are reviewed in this paper. The advantages and disadvantages of various TLC plates, adsorbants, developing solvents, and color developing reagents are discussed. The importance of prechromatographic extraction of urine and quality control for drug screening by TLC is also covered. - J. Planar Chromatogr. 2, 410-419 (1989). Minnesota Racing Anal. Lab., Dept. Vet. Diagn. Investig., Coll. Vet. Med., Univ. Minnesota, St. Paul, MN (USA)

Ultraviolet photolysis and ortho-phthalaldehyde-mercaptoethanol derivatization of pharmaceuticals for enhanced fluorescence detection in HPLC. B.M. Patel, H.A. Moye and R. Weinbcrger.

Verschiedene Klassen stickstoffhaltiger pharmazeutischer Verbindun- gen werden nach HPLC-Trennung fluorimetrisch bestimmt. Um auch originfir nicht fluorescierende Substanzen auf diese Weise erfassen zu k6nnen, wird ein post-column-Verfahren von UV-strahlungsinduzierter Photolyse mit anschliel3ender Derivatisierung durch o-Phthalaldehyd-2-

Mercaptoethanol (OPA-MERC) beschrieben. Auch UV-Photolyse allein wird in Wasser und in Gemischen von Methanol und Wasser (1 : 1) sowie Acetonitril und Wasser (I:1) untersucht. Dabei zeigt sich, dal3 Aceton sensibilisierend wirkt. Die bei der UV-Behandlung + Reaktion mit OPA-MERC entstehenden Fluorophore k6nnen in einem Fluores- cenzdetektor bestimmt werden. Beispiele einer Reihe von Pharmazeu- tika, die ffir diese Behandlung geeignet sind, werden beschrieben. Dabei werden Nachweisgrenzen im ng-Bereich erzielt. - Anal. Lett, 22, 3057 - 3079 (1989). Food Sci. and Human Nutr. Dept.,Pesticide Res. Lab., Univ., Gainesville, FL (USA) W. Czysz

Some applications of multidimensional gas chromatography to the enrichment of minor components in essential oil analysis. C. Bicchi, A. D'Amato, C. Frattini, G.M. Nano and A. Pisciotta.

The use of multidimensional gas chromatography (MDGC) for the analysis of essential oils is gaining in importance. A rarely used application consists in the enrichment of minor components through a MDGC system provided with a cold trap between trap column and analytical column. Under suitable conditions, in fact, the cold-trap can store a trapped compound (or a fraction) for a long time. Consequently, the same fraction can be heart-cut from several successive chromatographic runs on the first column and stored together in order to accumu- late trace compounds; afterwards the accumulated fraction can be injected in the analytical column. The possibilities of this technique will be illustrated through some examples of analysis of complex essential oils. - J. High Resolut. Chromatogr. 12, 705-708 (1989). Dipart. Sci. Tecnol. Farm., Torino (I)

Positive and negative chemical ionization GC/MS and GC/MS/MS for chromatographic studies of vetiveryl acetate. Use of MS]MS for the differentiation of isomeric sesquiterpenes. A. Cazaussus, P.Y. Roz6 and N. Sellier.

The acetylated fraction of a Vetiver oil from Java has been analyzed by GC/MS and GC/MS/MS with different ionization methods. 92 compounds were characterized and nine of them identified. The differentiation of isomers as methyl isozizanoate and methyl zizanoate confirmed the sensitivity, specificity, speed and accuracy of tandem mass spectrometry. - Chromat0graphia 28, 579-584 (1989). Lab. Spectrom. Masse, E.N.S.C.P.-C.N.R.S., Paris (F)

Electrochemical behavior of a phospholipid modified glassy carbon electrode. O. Chastel, V. Lopez, J.-M. Kauffmann and G.J. Patriarche.

Voltammetric oxidation of organic pharmaceuticals at a phospholipid modified glassy carbon electrode gives informations concerning the interaction drug-phospholipids. Measurements realized using the preconcentration technique allow interesting sensitivity improvements. The influence of several physico-chemical parameters has been investigated in order to optimize the electrode response. The accumulation process has been shown to be highly related to the charge beared by the phospholipid and by the molecule. The lipid modified electrode allows selective and quantitative measurements down to i x I0 -v M. -- Analusis 17, 581 586 (1989). Inst. Pharm., Univ. Libre de Bruxelles (B); Fac. Cie., Univ. Autonoma, Madrid (E)

Applications of ferrocene as a label for the liquid chromatography- amperometric analysis of some carboxylic, amine and carbonyl derivatives. N. Kubab, R. Farinotti, C. Montes, J. Chalom and G. Mahazier.

Derivatization methods using ferrocene reagents have been developed for the determination of carboxylic, amino and aldehyde group by HPLC with electrochemical detection. Among the reagents examined trimethylaminomethyl ferrocene iodide (I), ferrocene carboxaldehyde (II), ferrocenoylchloride (III) and ferrocenecarboxyhydrazide (IV) proved to be satisfactory with respect to reactivity, stability and electrochemical properties. Maximal sensitivity was observed at +0.5 V with I and II derivatives and at +0.75 V with III and IV derivatives, with a detection limit of 0.5 pmol. The polarity of the derivatives allowed their separation by RP-LC. The methods were found to be applicable to the monitoring of some drugs and drug metabolites. - Analusis 17, 559- 564 (1989). Univ. Paris-Sud, Centre d'6tudes pharm., Lab. Chim. Anal. II, Chatenay-Malabry (F)


Spectrophotometric determination of diphenadione via its metal complexes. S.Z. E1-Khateeb.

Zur Bestimmung des Anticoalgulans Diphenadion (2-(Diphenylace- tyl)-l,3-indandion) wird ein photometrisches Verfahren entwickelt, das auf der direkten Extinktionsbestimmung der Metallkomplexe mit Fe(III), Fe(II) oder Co(II) bei 488 nm, 505 nm und (334 nm, 372 nm) beruht. Das Metall: Metall-Verh/iltnis betrfigt 3 : 1 bei Fe(III) und 2:1 bei den beiden anderen Komplexen. Die molaren Extinktionskoeffizienten werden mit 1,48 x 103, 0,74x 103 und (1,70 x 103, 1,93 x 103) 1 tool -1 cm- 1 angegeben, die Richtigkeit mit 99,79 __ 0,6%, 99,64 + 0,37% und (100,09 _+ 0,53%, 99,99 +_ 0,42%). Die Arbeitsbereiche liegen bei 51 - 400 pg/ml Diphenadion beim Fe(II)-Komplex, bei den beiden anderen Komplexen bei 35-170 gg/ml Diphenadion. - Anal. Lett. 22, 2813- 2834 (1989). Pharm. Chem. Dept., Co11. Pharm., King Saud Univ., Riyadh (Saudiarabien) W. Czysz

Spectrophotometric determination of phenolphthalein in pharmaceutical products using 3-methylbenzthiazolinone-2-hydrazone. N. Geeta, A.P. Veena and T.R. Baggi.

A sensitive spectrophotometric method for the determination of phenolphthalein using 3-methylbenzthiazolinone-2-hydrazone in the presence of ceric ammonium sulfate as an oxidizing agent is presented. Beer's law is obeyed in the concentration range of 0 - 8 pg ml 1. The method is accurately reproducible and can be applied in the analysis of phenolphthalein and its formulations. The thin layer chromatographic and infrared studies of the colored coupling products were also performed. - Microchem. J. 40, 304-310 (1989). Cent. Foren. Sci. Lab., Burg. Pol. Res. Dev. (MHA), Ramanthapur, Hyderabad (IND)

High pressure liquid chromatographic analysis and dissolution of famoti- dine in tablet formulation. M.A. Sheikh Salem, H.N. Alkaysi and A.A. Badwan.

Zur quantitativen Bestimmung des Histamin-Ha-Rezeptor-Antagoni- sten Famotidin wird ein HPLC-Verfahren beschrieben. Die Trennung erfolgt an einer LiChrosorb RP-18-S/iule (7 gm) unter Verwendung einer mobilen Phase aus 0,1 M Phospatpuffer, Acetonitril und Methanol (84:11:5), pH 6,5. Die Detektion erfolgt bei 285 nm. Das Verfahren weist gute Pr/~zision auf. Die Wiederfindungen bewegen sich zwischen 99,86 __+ 0,787% und 101,28 + 0,682% (Dotierung 5 und 10 ~tg Famoti- din). - Anal. Lett. 22, 2501--2510 (1989). Fac. Pharm. Univ. Sci. Technol., Irbid (JOR) W. Czysz

Thin layer chromatography and structure-retention relationship of N-(2- ethylbutyryl)-N'-substituted imidocarbonic diamides. L. Ekiert and J. Bojarski.

Thin layer chromatographic separations of several di- and tri-substituted derivatives o f biuret were performed on normal and reversed phases. The best results were obtained on RP-18 plates (Merck), using water/methanol mixtures as mobile phases. A few reagents yielding color reactions were investigated for selective detection. The retention parameters (RM values) were correlated with the structure of the investigated compounds expressed in terms of the first order molecular con- nectivity indices and Van der Waals volumes. Statistically significant correlations were found for two groups of compounds differentiated by their ability to form intramolecular hydrogen bonds. - J. Planar Chromatogr. 2, 447-451 (1989). Dept. Org. Chem., Med. Acad., Krak6w (PL)

HPLC assay validation studies for bulk samples of a new analgesic. D.A. Roston and G.M. Beck.

A reversed-phase, ion-pairing HPLC method for assaying bulk samples of a new analgesic, 2,6-dimethyl-L-tyrosyl-N-(3-phenylpropyl)- D-alaninamide (DTPA), has been developed. The method is validated with a multiday, intralaboratory protocol. Key aspects of the validation concern characterizing method precision, linearity of response, selectivity, sensitivity, and method ruggedness. Preliminary validation data are generated with a photodiode array detector using multiple wavelengths. The validated method is used to characterize the purity of DTPA lots relative to a DTPA reference standard. - J. Chromatogr. Sci. 27, 519-523 (1989). Searle Res. Dev., Skokie, IL (USA)

HPLC of ketorolac enantiomers and application to pharmacokinetics in the rat. F. Jamali, F.M. Pasutto and C. Lemko.

A stereospecific HPLC assay was utilized to study the pharmacokinetics of the enantiomers of the antiinflammatory drug (_+)-ketorolac in the rat. Following derivatization with ethyl chloroformate/L- leucinamide the diastereomer were resolved on a 5 gm octadecyl silica column using acetonitrile/phosphate mobile phase with UV detection at 280 nm. Plasma enantiomer concentrations were superimposable but the S:R concentration ratios of conjugated KTR in urine ranged from 1.10 to 2.93. The assay appears to be readily applicable to the study of enantioselective KTR pharmacokinetics in humans. - J. Liquid Chromatogr. 12, 1835-1850 (1989). Fac. Pharm. Pharmac. Sci., Univ., Edmonton, Alb. (CDN)

Quantitation of ketoprofen in isopropyl myristate by high-performance liquid chromatography. S.-C. Chi and H.W. Jun.

An HPLC procedure with UV detection has been developed for the quantitation of ketoprofen released into isopropyl myristate used as the receptor phase in an in vitro membraneless drug diffusion cell. The drug and the internal standard (naproxen) were extracted from isopropyl myristate with a mixture of dimethyl sulfoxide/methanol/water (2:1 :I) and quantitated using a reverse phase C18 column. The chromatograms were completely free from interfering peaks, and the relative retention times of the internal standard and ketoprofen were 6.5 and 7.7 rain, respectively. Calibration plots were linear over the concentration range of 0.5-200 gg/ml of ketoprofen with the correlation coefficients all higher than 0.999. The mean recoveries for the calibration range were 93.9 __ 3.0% for the drug and 96.4 _+ 0.5% for the internal standard. The method is simple, reliable and accurate for the quantitation of ketoprofen in unpurified isopropyl myristate. - J. Liquid Chromatogr. 12, 2931-2945 (1989). Dept. Pharm., Coll. Pharm., Univ., Athens, GA (USA)

Stability-indicating assay for sulindac in tablet formulations by reverse- phase HPLC. I.M. Jalal, H.S. Khalil, and D. Jawhari.

A simple and stability-indicating HPLC procedure is described for the determination of sulindac in tablet formulations. Potential degradation products of sulindac were separated, thus rendering the method selective and stability-indicating. The assay is accurate, precise and can be used to test the content uniformity of tablets. The extraction procedure for the active ingredient from the tablets is very simple. The mobile phase is composed of 50 volumes of 0.05 M ammonium acetate adjusted to pH 6.0 with glacial acetic acid and 50 volumes of methanol. The column used was ultrasphere XL ODS (70 x 4.6 mm i.d.) (3 gin). UV detection at 280 nm and propyl paraben was used as internal standard. The proposed HPLC method was verified for linearity, specificity, accuracy and reproducibility. - J. Liquid Chromatogr. 12, 3087-3101 (1989). A1-Hikma Pharm., Amman (JOR)

Enantiomeric separation of aminoaleohols by TLC using a chiral counterion in the mobile phase. A.-M. Tivert and A. Backman.

Zur Trennung und zum qualitativen Nachweis der enantiomeren 13- Rezeptoren Alprenolol (A) und Propanolol (P) an Diol F254 HPTLC- Platten mit Dichlormethan + 0,4 mMol Ethanolamin als FlieBmittel wird diesem 5 mMol N-Carbobenzoxyglycyl-L-prolin zugesetzt. Nach Zweimalentwicklung erfolgt die densitometrische Bestimmung bei 280 nm (A) bzw. 300 nm (P), jeweils mit Subtraktion des Untergrundes bei 350 nm. Die Enantiomerentrennung ist bei P ausgeprfigter als bei A. - J. Planar Chromatogr. 2, 472-473 (1989). AB Hfissle, Dept. Anal. Chem., M61ndal (S) K.F. Becker

Quantitative determination of hydralazine hydrochloride and phthalazine in aqueous solutions by high-performance liquid chromatography. S. Halasi and J.G. Nairn.

A HPLC assay for separating and determining the concentration of hydralazine hydrochloride and phthalazine, a decomposition product, in aqueous solutions was developed. It was found that the separation and determination could be carried out using isocratic elution with a reverse phase CN column 0.46 cm i.d. by 15 cm in length, with a pore size of 5 pm. The mobile phase consisted of 850 ml of 0.04 M sodium formate/0.062 M formic acid, pH 3.5 and 150 ml methanol delivered at

2.8 Pharmaceuticals and cosmetics 683

a flow rate of 1.0 ml/min. The eluent was monitored at 258 nm. A linear relationship was obtained for the peak height ratio for both hydralazine hydrochloride and phthalazine against the internal standard phenyleph- fine hydrochloride over the range of 2 to 16 and 2 to 12 pg/ml respectively. - J. Liquid Chromatogr. 12, 2397-2403 (1989). Fac. Pharm., Univ. Toronto, Toronto, Ont. (CDN)

Investigation of conformational diastereomers of 2,3-benzodiazepines by high-performance liquid chromatography. I. Fellegvfiri, J. Visy, K. Valk6, T. Lfing and M. Simonyi.

4-Methyl-5-ethyl-5H-2,3- benzodiazepine derivatives in ethanolic solution can exist in two conformations which interconvert into each other. The kinetic properties of interconversion for six derivatives were investigated by HPLC using silica stationary phase. The rate constants (kl +k2), half lives and equilibrium constants (K) of interconversion were calculated from the concentration ratios obtained at various time intervals after dissolving the compounds in ethanol. Correlation was found between K and (kl + k2) for five compounds except one involving basic substituent and exhibiting extremely high rate of interconversion. Hammett correlation was found for the equilibrium constant suggesting a decline from linearity for higher 8 values. The rate of interconversion decreased by increasing volume of non-basic substituents in the i -phenyl ring. - J. Liquid Chromatogr. 12, 2719-2732 (1989). Cent. Res. Inst. Chem., Hung. Acad. Sci., Budapest (H)

Spectrofluorimetric method for the determination of 1-(3,4-dimethoxyphenyl)-4-methyl-5-ethyl-7,8-dimethoxy-5H-2,3-benzodiazepine (tofisopam). I. Kfisa, H. Horny~k, J. K6r6si and T. Hfimori.

The method described is based on the reaction of tofisopam in dimethyl sulfoxide in the presence of an alkali metal hydroxide at 9 0 - 100°C to give 1-ethyl-4-(3,4-dimethoxyphenyl)-6,7-dimethoxy-2-naphthol, which shows intensive fluorescence. The method is suitable for the determination of 5 x 10- s _ 5 x 10- 5 g ml- 1 of tofisopam. - Anal. Chim. Acta 227, 315--318 (1989). Dept. Phys. Chem., Techn. Univ., Budapest (H)

Extraction-spectrophotometric method for determination of clemastin in pharmaceutical preparation. J. Sutkowska, G. Rynarzewska and F. Matecki.

Zur Gehaltsbestimmung von Clemastin in Tabletten und Ampullen wird das Probenmaterial in 10 ml dest. Wasser gel6st und flltriert (Tablet- ten). Anschliel3end wird 1 ml entnommen und mit 5 ml 0,2 M Acetatpuf- fer (pH 5,5) sowie 0,7 ml 0,2 M Eriochromschwarz T in Methanol versetzt. Nach Ergfinzen mit Wasser zu 10 ml und Zugabe von 10 ml Chloroform wird 2 min extrahiert. Die Absorption des gebildeten Ionen- paares wird nach 20 min bei 518 nm gemessen. Die Eichgerade zeigt Linearit~it von 2 20 pg Clemastin/ml. Zur optimalen Bildung des Ionen- paares soll die Farbstoffkonzentration das Doppelte der Clemastinkon- zentration betragen. Zwischen pH 4,5 und 5,5 wird der fiberschtissige Farbstoff nicht mitextrahiert. - Pharmazie 44, 862-863 (1989). Dept. Anal. Chem. School Med., Wroctaw (PL) W.H. Mennicke

Colorimetrie determination of terbutaline and orciprenaline through ni- tration and subsequent treatment with acetyl acetone in alkaline medium. M. E1-Sadek, H.A. Latef and A.A. Khier.

Zur Bestimmung yon Terbutalinsulfat, Orciprenalinsulfat und ihren pharmazeutischen Formulierungen wird ein colorimetrisches Verfahren vorgeschlagen. Es basiert aufder Bildung der Trinitroderivate (Nitrierge- misch: 3 ml konz. HNO3 + 7 ml konz. HaSO~). Diese werden anschlie- Bend einer Ladungstransfer-Komplexierungsreaktion mit Acetylaceton als Donor unterzogen (unter Zugabe von 20%iger KOH-L6sung). Die Extinktionen werden ffir beide Verbindungen bei 405 nm gegen die Reagentienblindl6sung gemessen. Das Beersche Gesetz ist fiir beide Ver- bindungen im Bereich 4 - 32 gg/ml erffilit. Prfizisionen und Richtigkeiten sind gut. Das Verfahren kann zur Bestimmung der Wirkstoffe in Tablet- ten und Ampullen eingesetzt werden. - Anal. Lett. 22, 2511-2519 (1989). Pharm. Chem. Dept., Fac. Pharm., Univ., Zagazig (ET)

W. Czysz

Spectrophotometric determination of some benzene sulfonamides with 7,7,8,8-tetracyanoquinodimethane. A.-M.I. Mohamed.

A new spectrophotometric method for the determination of some unsubstituted benzene sulfonamides is presented. The method is based on the interaction of these derivatives with 7,7,8,8-tetracyanoquinodimethane at pH 9.0-9.5 to produce intense blue products. The quantitation of the products was carried out at 578 nm. Beer's law was obeyed over a wide range of concentrations for all sulfonamide compounds studied. Optimum analytical conditions were determined, and the color produced was stable for at least 90 min at 25°C. Analytical data for determination of sulfonamide compounds in pure form are presented together with application of the proposed method for analysis of some commercially available pharmaceutical preparations. The results are in good agreement with those obtained by official procedures. - J. Assoc. Off. Anal. Chem. 72, 885- 889 (1989). Dept. Pharm. Chem., Fac. Pharm. Univ., Assiut (ET)

Differential pulse polarographic determination of some substituted ben- zylidene acethydrazones. M.M. Kamal, Y.M. Temerk, Z.A. Ahmed and Abd-E1-Wahab.

Die Differentialpulspolarographie ftir die Spurenbestimmung yon Benzylideuacethydrazon (BAH), 2- und 4-Hydroxy-, 4-N,N-Dimethyl- amino- und 4-Nitro-BAH als m6gliche Tuberculostatica wird untersucht. Optimale Bedingungen sind pH 5,08 (Britton-Robinson-Puffer), 30 rain entlfiften, Tropfzeit 1 s, Scanrate 2 mV/s, Pulsamplitude 100 inV. Die Bestimmungsgrenzen liegeu bei den substituierten BAH zwischen 0,099 und 0,199 pMol, fiir BAH bei 0,799 pMol. Die linearen Konzentrations- bereiche sind angegeben. Durch Komplexbildung mit/]bergangsmetal- len (beschrieben nur for Cu und 4-Nitro-BAH) wird bei pH 4,02 die Bestimmungsgrenze herabgesetzt. Analusis 17, 532--535 (1989). As- suit Univ., Fac. Sci., Chem. Dept., Assiut (ET) K.F. Becker

Simultaneous determination of lonidamine, l-(2,4-dichlorobenzyl)-lH-in- dazole-3-carboxylic acid, a new antitumoral, and its impurity, N2 substituted isomer, by UV derivative spectrophotometry. C. Vetuschi and G. Ragno.

Verff. beschreiben ein derivativ-UV-spektralphotometrisches Verfah- ren zur Bestimmung des neuen Antitumorwirkstoffs Lonidamin (chemi- scher Name, siehe Titel) und des als Nebenprodukt bei der Synthese entstehenden N2-alkylierten Isomers. Die Richtigkeit des Verfahrens wird durch Regressionsanalyse einer gr6geren Anzahl yon Standardl6- sungen fiberprtift. Man erhfilt richtige und reproduzierbare Ergebnisse, die f/Jr den Anspruch der Analyse yon Laborgemischen und yon kommerziellen PrS.paraten genfigen. - Anal. Lett. 22, 1685-1692 (1989). Dip. Farm. Chim., Univ., Bari (I) W. Czysz

High-performance liquid chromatographic separation of taxol and related compounds from Taxus brevifolia. K.M. Witherup, S.A. Look, M.W. Stasko, T.G. McCloud, H.J. Issaq and G.M. Muschik.

Taxol, ein hoch-funktionalisiertes Taxan-diterpenamid mit antitumor- und antileuk/imischen Eigenschaften wird ffir Klinikversuche im Kilo- magstab aus den Methanol-Extrakten der Rinde der westlichen Eibe (Taxus brevifolia; Taxaceae) extrahiert. Silicagel mit gebundenen Cyan- und Phenyl-Gruppen dient als stationfire Phase in der Umkehrphase- Fltissig-Chromatographie fiir empfindliche Methoden und wird nun zur Bestimmung und Nachweis von Taxol und 4 verwandten Taxanen eingesetzt. Diese sind Cephalomannin, 10-Deacetylcephalomannin, Baccatin III, und 10-Deacetylbaccatin III; sie sind im rohen Methanol-Extrakt sowie dessen Methylenchlorid-16slichen Anteilen enthalten. Ein Gemisch dieser Substanzen wird je nach der isokratischen und der Gradienten- Methode aufgetrennt. Isokratische Elution auf der Phenyl-Sfiule gibt ffir Taxol einen linearen Bereich yon 5 ng bis 10 pg. Zur Quantifizierung in Methylenchlorid-Extrakten wird die Methode der Standard-Zusfitze gewfihlt. Die Vorreinigung der rohen Extrakte, kombiniert mit der Gra- dienten-Elution vermindert die Peak-/Jberlappung und erh6ht die analytische Prfizision. - J. Liquid Chromatogr. 12, 2117-2132 (1989). Pro- gram Resources Inc., NCI Frederick Cancer Res. Facility, Frederick, MD (USA) B.R Glutz

Electroanalytical behaviour of 2-thioorotic acid. J. Rodriguez, L. Calvo, C. Matin and A. Sanchez.

Das elektroanalytische Verhalten der gegen Virusinfektionen wirksa- men 2-Thioorots/iure wird bei verschiedenen pH-Werten und unter An-


wendung mehrerer Methodenvarianten (Gleichstrom- und Differential- puls-Polarographie und cyclische Voltammetrie) untersucht. Dabei wird festgestellt, dab die Verbindung im gesamten pH-Bereich, der hierffir in Frage kommt, drei Reduktionsstufen aufweist: die erste zwischen pH 0,80 und 4,40 mit einem konstanten Peakstrom bei pH 1,00; Stufe zwei zwischen pH 4,50 und 7,70 mit einem Peakmaximum bei pH 5,50; Stufe drei erscheint oberhalb pH 5,50 und zeigt einen konstanten Peakstrom im pH-Intervall 7,70-8,90. Aus der Beobachtung dieses Verhaltens wird, unter Einbeziehung auch des gfinstigsten Temperaturbereichs, ein Verfahren zur Bestimmung der 2-Thioorots/iure empfohlen. - Anal. Lett. 22, 2145-2154 (1989). Dept. Anal. Chem. Electrochem., Univ. Extremadura, Badajoz (E) W. Czysz

Liquid chromatographic determination of penicillin V potassium in tablets: Collaborative study. B. Mopper.

A LC method for the determination of penicillin V potassium in tablets was collaboratively studied by 7 laboratories. The method uses an octadecyl silane reverse-phase column, a mobile phase of acetonitrile/ methanol/0.01 M potassium phosphate monobasic (21:4:75), photometric detection at 225 nm, and sulfadimethoxine as an internal standard. Each collaborator received 6 samples; powdered composites of 2 commercial tablet preparations and 1 synthetic tablet powder mixture, each with blind duplicates. The mean repeatability and reproducibility relative standard deviation for commercial samples were, respectively, 1.10 and 1.46% (250 mg dosage), and 0.84 and 2.82% (500 mg dosage). The average standard recovery from the synthetic formulation was 99.1%, with repeatability and reproducibility relative standard devi- ations of 1.30 and 3.66%, respectively. The method has been adopted official first action. - J. Assoc. Off. Anal. Chem. 72, 883-884 (1989). Food Drug Admin., New York Reg. Lab., Brooklyn, NY (USA)

Analysis of a modified neutral cephalosporin by HPLC-photolysis-electrochemical detection. S.A. McClintock and M.L. Cotton.

A method for the determination of a modified neutral cephalosporin (L-658,758) by HPLC with electrochemical detection is described. After the separation the compound is irradiated with UV light in a knitted open tubular polytetrafluoroethylene post-column reactor. The resulting species produced is detected at a glassy carbon electrode maintained at 1.1 V vs Ag/AgC1 reference electrode. The system response is linear from I ng to 1 pg injected on column with a detection limit of 1 ng based on a signal three times the baseline peak-to-peak noise. - J. Liquid Chromatogr. 12, 2961-2969 (1989). Merck Frosst Canada Inc., Pointe Claire-Dorval, PQ (CDN)

Cyclic and linear sweep voltammetry of cefazolin and cefmetazole: Electroanalytical applications. E. Mufioz, L. Camacho, J.L. Avila and F. Garcia-Blanco.

A study of the variables influencing the voltammetric behaviour of cephalosporins and cefamycins bearing substituents of the S - R' type (R' = non-electroactive group) has been carried out in order to determine the most suitable conditions for obtaining reproducible peaks for the determination of both types of antibiotics and the calculation of kinetic and thermodynamic parameters. The voltammetric behaviour of cefazolin and cefmetazole has also been studied. The voltammetric peak yielded by these two antibiotics at high sweep rates and low concentrations is due solely to the reduction of adsorbed molecules as the contribution of those molecules moving to the electrode through diffusion to the current is negligible. The peak current of cefazolin varies linearly with its concentration in the range 10 9_ 10-7 M, whereas the linear range for cefmetazole is between 10 -8 and 5 x 10 -7 M, which allows the electroanalytical determination of the two antibiotics at these concentrations. - Analyst 114, 1611-1615 (1989). Dept. Phys. Chem. Appl. Thermodynamics, Fac. Sci., Univ., C6rdoba (E)

Improved separation of erythromycin on aged reversed-phase columns. Th. Cachet, I. Quintens, E. Roets and J. Hoogmartens.

It was previously observed that for HPLC of the antibiotic erythromycin better results were obtained on aged reversed-phase columns. Here it is shown that the chromatographic properties of short chain reversed-phase materials (C2, TMS or C8) are improved by heating at 120°C the column, containing a mobile phase methanol/1M phos-

phoric acid/water. Analysis of the packing materials prior and subsequent to the aging procedure reveals that all materials lose a part of the bonded phase. Silanoi interaction as measured by the adsorption of methyl red increases consequently. The stability of the reversed-phase materials upon aging in acidic conditions depends on the chain length and the type of derivatisation. The results confirm that shorter chain reversed-phases and materials prepared with monofunctional .silylating reagents are more labile. - J. Liquid Chromatogr. 12, 2171-2201 (1989). Kathol. Univ. Leuven, Lab. Farm: Chem., Leuven (B)

Coordination chemical studies of some polymeric transition metal complexes with neomycin and their biological activity uses. Indirect determination of neomycin by atomic absorption spectroscopy (AAS). S.M. Abu-E1-Wafa, M.A. E1-Ries, F.M. Abou-Attia and R.M. Issa.

Verff. beschreiben ein indirektes Verfahren zur Bestimmung yon Neomycin. Sic verwenden dazu polymere f0bergangsmetallkomplexe mit Co(II), Ni(II), Cu(II) oder Zn(II) und Carbonat als Hilfsligand. Man versetzt die Neomycinl6sung in Gegenwart von Natriumcarbonat mit der betreffenden fAbergangsmetallsalzl6sung bekannter Konzentration, zentrifugiert den sich biidenden, das Neomycin enthaltenden Nieder- schlag ab und bestimmt den in der iiberstehenden L6ung verbliebenen f.)berschuB und Metallsalz nach Atomisieren durch Flammen-AAS. Die in Tabellen angegebenen Werte zeigen, dab das Verfahren zu pr/izisen und richtigen Ergebnissen ffihrt. - Anal. Lett. 22, 2703-2716 (1989). Dept. Chem., Fac. Educ., Ain Shams Univ., Roxy, Cairo (ET)

W. Czysz

Identification of tetracyclines by TLC. W. Naidong, T. Cachet, E. Roets and J. Hoogmartens.

The procedure described permits the identification of chlortetra- cycline, demeclocycline, doxycycline, metacycline, minocycline, oxy- tetracycline, and tetracycline by TLC on silica gel layers, previously sprayed with a 10% solution of sodium edetate adjusted to pH 7.0, 8.0 or 9.0, with dichloromethane/methanol/water (59:35:6) as the mobile phase. The influence of the humidity of the silica gel layer on the separation of tetracyclines has been studied. Reversed-phase chromatography on silanized silica gel was also examined, and was found to give less satisfactory separations than those obtained on silica gel, The described method is applicable to laboratory-prepared layers and precoated plates of various other origins. - J. Planar Chromatogr. 2, 424-429 (1989). Kathol. Univ., Lab. Farm. Chem., Inst. Farm. Wetensch., Leuven (B)

Identification and qnantitation of tetracycline antibiotics by cyanophase HPTLC. J.S. Kang and S. Ebel.

The separation of tetracycline antibiotics using cyanophase HPTLC plates and methanol/acetonitrile/0.5 M aq. oxalic acid as eluent is described. This eluent is optimized with respect to the separation of the most frequently used compounds (tetracycline, chloro- and oxytetra- cycline, and demechlocycline). There is no advantage to using acetone as eluent even though it is very strongly, a hydrogen bond acceptor. The results of quantification of doxycycline by using densitometry at 254 nm are present as an example. In the range from about 400 to 900 rig/spot there is an almost linear dependance of relectance on the amount of substance within a spot. Therefore, linear regression, as well as nonlinear regression techniques with the common saturation function, may be used for calibration purpose. - J. Planar Chromatogr. 2, 434-437 (1989). Dept. Pharm., Univ., Wfirzburg (D)

Determination of colistin concentration by isotachophoresis. W. Holska and E. Gw6zdz.

In a simple isotachophoretic system the correlation between the zone area and the concentration of colistin is linear. Leading electrolyte: 10 mM HC1 with 0.3 % hydroxypropylmethylcellulose; terminating electrolyte: 10 mM Tris. The apparatus used was LKB 2127 Taehophor with UV detection at 206 nm and on HP 3390 integrator. The current was 150 pA, the temperature 5°C, the 10-30 rain duration of the analysis depends on the sample. This method was applied for determination of colistin in the drug as well as in intermediate stages of the production of colistin. It was found good agreement between results obtained with isotachophoresis, HPLC and the biological estimations. -- J. Liquid

3 Biochemical and clinical analysis 685

Chromatogr. 12, 2761-2767 (1989). Tarchomin Pharmac. Works "Polfa", Anal. Dept,, Warsaw (PL)

Turbidimetric determination of phenformin by flow injection analysis. J. Martinez Calatayud and A. Sanchez Sampedro.

The study of some phenformin-counteranion compounds was carried out in order to determine the suitable precipitate for phenformin determination using a flow injection manifold. The selected reagent, tungstate, gives a white precipitate. FIA variables were established using the modified simplex method and the calibration graph is linear over the range 120-222 ppm of phenformin. The method is proposed for control analysis on pharmaceutical formulations of phenformin and it is based on the direct injection of the drug into one stream of 0.060 M tungstate solution with pH and ionic strength 2.00 and 0.15 M NaC1, respectively. - Analusis 17, 413 - 416 (1989). Dept. Quire. Anal., Coleg. Univ. CEU, Moncada (Valencia) (E)

Photoehemically induced fluorimetric determination of the antimalarial mefloquine. J. Fidanza and J.J. Aaron.

Mefloquine (MQ) was determined quntitatively in pharmaceutical tablets by irradiating the MQ solution for 2 - 7 min with a high-pressure UV lamp, measuring simultaneously the increase in fluorescence signal at room temperature (298 K) and comparing the signal with that of a standard. The effect of several solvents (acetone, dioxane, ethanol, methanol, propan-2-ol, tetrahydrofuran, water) and "pH" on the fluorescence properties of MQ and its photochemical decomposition product were studied. The limit of detection of MQ was 50 ng ml 1. The mean overall recovery from pharmaceutical tablets was 102.3 ± 4%. - Anal. Chim. Acta 227, 325-330 (1989). Fac. Sciences, Centre Univ., Avignon (E)

Liquid chromatographic and mass spectral analysis of methoxyamphetamines and methoxymethamphetamines. F.T. Noggle, Jr., C.R. Clark and J. DeRuiter.

The 2-, 3-, and 4-methoxyamphetamines and methoxymethamphetamines were prepared by reductive anaination of the corresponding ke- tones. The compounds have a wavelength of maximum absorption in the UV range around 271 nm and a molar absorptivity of 1.0 x t03 1/ mol cm. The compounds were separated by RP-LC with a C ~ 8 stationary phase and acidic aqueous acetonitrile mobile phase. The mass spectra showed the amine-dominated fragmentation pattern with molecular ions of very low relative abundance. - J. Chromatogr. Sci. 27, 602-606 C1989). Alabama Dept. Foren. Sci., Auburn, AL (USA)

Liquid chromatographic and mass spectral analysis of N-substituted analogues of 4-methoxyamphetamine. F.T. Noggle, Jr., C.R. Clark, C.L. McMillian and J. DeRuiter.

A number of N-alkyl substituted 4-methoxyamphetamines were synthesized and characterized as potential designer drugs related to the amphetamines. These amines were prepared via reductive amination of 4-methoxyphenylacetone with appropriate alkylamines. The UV absorption properties of the compounds are very similar, displaying absorption maxima at 274 nm and absorptivities of 1.4 x 103 l/tool cm. The amines were separated by RP-LC using an acidic aqueous acetonitrile mobile phase and several hydrocarbon stationary phases. The mass spectra of the N-alkyl analogues show an amine-dominated fragmentation pattern with molecular ions of very low relative abundance. These amines can be readily distinguished from each other and other amphetamine-type compounds on the basis of their unique chromatographic and spectral properties. -- J. Chromatogr. Sci. 27, 607-61l (1989). Alabama Dept. Foren. Sci., Auburn, AL (USA)

The method is precise and accurate and compares favorably with the established HPLC method. Substances like mace, henna, and nutmeg do not interfere with the method. - Microchem. J. 40, 297-303 (~989). Cent. Foren. Sci. Lab., Bur. Pol. Res. Dev. (MHA), Ramanthapur, Hyderabad (IND)

Quantitative densitometric HPTLC determination of cetalkonium chloride in a gel preparation (Mundisal Gel). K. Wenz and B. Renger.

Zur Bestimmung yon N-Benzyl-N,N-dimethylhexadecylammoni- umchlorid in Gelzubereitung mit Cholinsalicylat und Ethanol werden 150 mg Gel mit 150 ~1 2% w/il3riger NaHCO3 20 mg BaC12 und 150 gl Ethylacetat 5 rain gemischt und 5 rain mit 10000 U/rain zentrifugiert. Von der klaren F1/issigkeit wird I gl auf Silicagel HPTLC-Platten 10 x 10 cm aufgetragen und mit n-Butanol/Eisessig/Wasser (66:17:17) 8 cm entwickelt. Die Flecken werden mit Hexaiodplatinat sichtbar gemacht und densitometrisch bei 600 nm ausgewertet. Die Wiederfindungsrate betrfigt 99,4 ± 3,2%. - J. Planar Chromatogr. 2, 476-477 (1989). Byk Gulden Pharmazeutika, Konstanz; Mundipharma GmbH, Limburg (Lahn) (D) K.F. Becker

3 BIOCHEMICAL AND CLINICAL ANALYSIS

Performance of an integrated biosensor composed of a mediated and an oxygen-based glucose sensor under unknown oxygen tension. K. Yoko- yama, E. Tamiya and I. Karube.

Zur Glucosebestimmung wird ein aus zwei Einzelsensoren zusammen- gesetzter Mikrosensor entwickelt. Er besteht aus einem Sensor auf der Grundlage von immobilisierter Glucose-Oxidase (GOD) unter Verwen- dung yon 1,1"-Dimethylferrocen als Elektronenvermittler (Mediated Glucose Sensor; MGS) in Kombinatiou mit einem ,,normalen" Glucose- sensor auf der Basis O2/GOD (OGS). Die Responsen beider Sensoren werden (unterschiedlich) durch die Konzentration yon gel6stem Sauer- stoff beeinflul3t. Die Response des MGS wird bei der Auswertung auf der Grundlage der Response der OGS rechnerisch korrigiert. Auf diese Weise erhS~lt man Ergebnisse, die von der Konzentration an gel6stem Sauerstoff unbeeintr/ichtigt sin& Konstruktion der kombinierten Elek- trode, Versuchsanordnung und -durchffihrung, s. Original. - Anal. Lett. 22, 2949-2959 (1989). Res. Cent. Adv. Sci. and Technol., Univ. Tokyo, Meguro-ku, Tokyo 153 (J) W. Czysz

Oxalate, phosphate and sulfate determination in serum and urine by ion chromatography. L. Politi, R. Chiaraluce, V. Consalvi, N. Cerulli and R. Scandurra.

Serum is deproteinized through a Centrifree filter by centrifugation and the ultrafiltrate directly injected into an ion chromatograph equipped with an anion exchange column and a conductivity detector. By this procedure the sample is not diluted and even small amounts of oxalate in biological fluids can be detected. Mean serum concentration found in healthy individuals are: phosphate 1.07 mmol/1; sulfate 0.35 mmol/1; oxalate 21.02 gmol/1. Phosphate, sulfate and oxalate contents were also determined in urine from healthy individuals. Values found in serum and urine are in good agreement with those previously reported. - Clin. Chim. Acta 184, 155-166 (1989). Dipart. Sci. Biochim., Inst. Urol., Univ. La Sapienza, Rome (I)

Quantitation of A9-tetrahydrocannabinol in cannabis using 3-methyl benzthiazolinone 2-hydrazone. K. Lavanya and T.R. Baggi.

A simple method for the estimation of A9-tetrahydroeannabinol (A 9- THC) in cannabis is reported. The method involves the oxidative coupling of cannabinoids in cannabis with 3-methyl benzthiazoiinone-2-hydrazone. The derivatized products are separated by TLC and one of the isomeric derivatives of Ag-THC is utilized for spectrophotometric estimation of Ag-THC. The nature of the derivative is studied using both infrared and mass spectrometry and the reaction mechanism is proposed.

Non-destructive determinationof aluminum in biological reference samples using neutron activation analysis. S. Landsberger and A.M. Arendt.

The non-destructive methods of thermal and epithermal neutron activation analysis have been employed to determine the aluminum concentration of seven National Institute of Standards and Technology certified biological reference materials. Through the judicious use of both thermal and epithermal neutron activation analysis using bare and boron-lined irradiation carriers, the major and minor contributions of the 31P(n,~)28A1 and of the 28Si(n,p)2SAl reactions, respectively, to the

686 3 Biochemical and clinical analysis

ZTAl(n,7)28A1 reaction could be corrected for explicitly. Based on replicate determinations precision of the analysis ranged from 2.5 % for citrus leaves determined at the 75 ppm level to 18% for bovine liver measured at the i ppm level. Accuracy was demonstrated whenever possible by comparison to existing published data. - J. Radioanal. Nuel. Chem., Lett. 137, 443--454 (1989). Dept. Nuclear Engin., Univ. Urbana, IL (USA)

Direct determination of lead in whole blood using electrothermal vaporization inductively coupled plasma atomic emission spectrometry. J. Alva- rado, P. Cavalli, N. Omenetto, G. Rossi, J.M. Ottaway and D. Little- john.

Zur Bestimmung yon Blei in Vollblut durch Atomemissionsspektro- metric mit elektrothermischer Verdampfung in das induktiv gekoppelte Plasma (ICP) benutzt man als Verdampfer einen Kohlestab. Parallel zur Probe werden Standards bekannter Bleikonzentration mit Triton X oder Salpeters/iure behandelt oder 1 + 5 mit dest. Wasser verdfinnt und dann in gleicher Weise bestimmt wie die Probe. Durch Vergleich der erhaltenen MefSkurven kann der Gehalt der Proben an Blei ermittelt werden. Beide Standardmodifikationen ffihren zu gleichen Ergebnissen und entspre- chen auch denen der Probemessung. Ein besonderer Matrixeffekt wurde nicht festgestellt. Bei Verwendung einer w/il3rigen L6sung von 1 gg Pb/ ml erh/ilt man unter optimierten Bedingungen ein Signal-zu-Untergrund- Verhgltnis yon 5,5. RSD der Blind- und analytischen Signale liegen bei 0,2 bzw. 1,8 %. Nachweisgrenze: 0,007 gg Pb/ml in w/iBriger LSsung. - Anal. Lett. 22, 2975-2984 (1989). CEC Joint Res. Centre, Chem. Div., ISPRA Establ., Ispra, Varese (I) W. Czysz

Use of a fragment of bovine serum albumin as a chiral stationary phase in liquid chromatography. P. Erlandsson and S. Nilsson.

Bovine serum albumin (BSA) was cleaved into fragments by proteolytic degradation. A fragment consisting of the N-terminal half of BSA was isolated an immobilized on a silica column. Compared with BSA- based columns, this column showed a retained stereoselective resolving capability for the enantiomers of oxazepam, benzoin und morpholep, whereas the enantiomers of, e.g., tryptophan and warfarin were not resolved. - J. Chromatogr. 482, 35-51 (1989). Dept. Techn. Anal. Chem., Chem. Center, Univ., Lund (S)

Analysis of a carcinogen, 4,4'-methylenedianiline, from thermosetting polyurethane during sterilization. H. Shintani and A. Nakamura.

Polyurethane (PU) is widely used in medical devices such as potting material in artificial dialysis devices, plasma separators, etc. Gamma- ray irradiation is frequently used for the sterilization of such devices. This paper reports that a carcinogen, 4,4'-methylenedianiline (MDA, p,p'-diaminodiphenylmethane), is produced from medical thermosetting PU by gamma-ray irradiation. Gamma-ray irradiated PU was immersed in methanol or equine serum. The serum was treated with a mixture of 5N HC104/acetonitrile (1 : 10) in order to deproteinate and recover MDA. It was found that MDA is formed from thermosetting PU at around a few ppm in the original sample. The production of MDA increased with increasing irradiation dose. The MDA amount formed was related to the irradiation dose by a second order equation. Results of methanol and serum extraction were similar. Pressurized steam (autoclave) sterilization in place of gamma-ray sterilization was also examined. MDA production was not found in autoclave sterilization procedures. Gel permeation chromatography (GPC) of methanol or N,N-dime- thylformamide (DMF) extract of irradiated PU showed that the PU oligomers eluted. Time course of methanol extract of irradiated PU was detected at 245.5 nm. This showed an exponential decline regardless of doses of irradiation. - J. Anal. Toxicol. 13, 354-357 (1989). Nat. Inst. Hyg. Sci., Dept. Med. Devices, Kamiyoga, Setagaya, Tokyo (J)

Intact chemoreceptor-based biosensors: extreme sensitivity to some excit- atory amino acids. R.M. Buch and G.A. Rechnitz.

Biosensoren auf der Basis intakter Chemorezeptoren werden zum Nachweis einiger Verbindungen benutzt, die zu den neuronalen Anre- gungs-Aminos/iuren gehSren: die in der Meeresalge Digenea simplex vorkommende Kainins/iure und die in Quisqualis-Pflanzen vorkommende Quisqualins~iure. Diese Anregungs-Aminos/iuren induzieren De- polarisation an Neuronen fihnlich der verschiedener Neurotransmitter.

Der besonders physiologisch/biochemisch zu interpretierende Aufbau des Sensors auf der Basis yon Chemorezeptoren wird beschrieben. Als chemotaktisch empfindliches Substrat verwendet man die Antennulen der blauen Krabbe Callinectes sapidus. Mit dieser Art Sensoren werden Empfindlichkeiten bis 10-1 s M erreicht, das sind etwa neun Gr6f3enord- nungen niedriger als mit traditionellen potentiometrischen Biosensoren mSglich ist. - Anal Lett. 22, 2685-2702 (1989). Hawaii Biosensor Lab. ; Dept. Chem., Univ. Hawaii et Manoa, Honolulu, HI (USA)

W. Czysz

Automated analysis of urinary hydroxyproline. K.-C. Ho and C.-P. Pang. Es wird eine modifizierte Methode zur Bestimmung von Hydroxypro-

lin in Harn beschrieben (C.-P. Pang u.a.: J. Chromatogr. 386, 309 (J987)). Arbeitsweise. Harnpeptide werden in 6 ml/1 HC1 hydrolysiert. Der pH-Wert des Hydrolysates wird auf 8,0-10,0 eingestellt. Die spek- trophotometrische Methode (Ehrlich-Reaktion) ist dadurch gekenn- zeichnet, dab der pH-Wert des sauren Hydrolysates bei etwa 6,0 liegt. Das Harnkreatinin wird mit der Jaffe-Reaktion und einem Astra 8- Analyzer bestimmt. Es hat sich ergeben, dab weder mit Hydroxylysin noch mit 3-Hydroxyprolin St6rungen mit dem 4-Hydroxyprolin-Peak auftreten. Fiir die selektive Bestimmung yon 4-Hydroxyprolin in Ham sind empfindlichere Methoden erforderlich. Eine ungeniigende Bindung von sauren Harnpeptiden zeigt sich in einem deutlichen Hydroxyprolin- verlust. Mit dem Cobas Bio Analyzer werden ausreichendfd genaue Befunde erhalten. Untersuchungen von 20 Proben nach der spektropho- tometrischen Methode und nach der HPLC ergeben Befunde mit ausrei- chender Genauigkeit. Die Regressionsgleichung lautet y = 0,94 x + 28,57. r-0,973. -- Clin. Chim. Acta 185, 191 -196 (1989). Dept. Chem. Pathol., Chin. Univ. of Hong Kong, Prince of Wales Hosp. Shatin, N.T. (HK) F. Knorr

Dependence of the silanophyl effect on the chemical structure of peptides and on the type of organic mobile phase in reversed-phase thin-layer chromatography. T. Cserhfiti, G. ()sapay and M. SzSgyi.

The retentions of 22 peptides in reversed-phase thin-layer chromatography are determined with methanol, ethanol, or n-propanol as the organic mobile phase. The majority of the peptides show a silanophyl effect: their RM values first decrease to a minimum and then increase with increasing organic phase concentration. The retention behavior of the peptides is adequately described with a quadratic function; the application of a bilinear function has no additional advantage. Principal component analysis (PCA) proves that each constant in the quadratic function depends on the lipophilicity of the peptides. On the basis of their retention characteristics, the peptides form four distinct groups in the two-dimensional nonlinear map of PC variables: peptides containing a basic amino acid, peptides containing an acidic amino acid, peptides with a ring structure in the amino acid side-chain, and peptides containing uncharged amino acids. Stepwise regression analysis indicates that the organic phase concentration corresponding to the minimum retention of the peptides increases with increasing lipophilicity of the peptides, and decreases with increasing lipophilicity of the organic mobile phase. - J. Chromatogr. Sci. 27, 540-544 (1989). Cent. Res. Inst. Chem., Acad. Sci., Budapest (H)

Derivafization of ?-glutamyl semialdehyde residues in oxidized proteins by fluoresceinamine. I. Climent, L. Tsai and R.L. Levine.

Oxidative modification of proteins is implicated in a number of physiologic and pathologic processes. Metal-catalyzed oxidative modification usually causes inactivation of enzymes and the appearance of carbonyl groups in amino acid side chains of the protein. We describe use of fluoresceinamine to label certain of those carbonyl groups. Fluor- esceinamine reacted with those carbonyl groups to form a Schiff base which was reduced by cyanoborohydride to yield a stable chromophore on the oxidized residue. The high molar absorbtivity of the fluorescein moiety conferred high sensitivity upon the method. Labeled peptides were readily identified after tryptic digestion of oxidized glutamine synthetase. Further, acid hydrolysis of labeled glutamine synthetase allowed isolation of the derivatized, oxidized residue. The oxidized amino acid was identified as y-glutamyl semialdehyde. During metal- catalyzed oxidation, the inactivation of glutamine synthetase paralleled the appearance of 7-glutamyl semialdehyde. - Anal. Biochem. 182,

3 BiochemicaI and clinical analysis 687

226-232 (1989). Lab. Biochem., Nat. Heart, Lung, Blood Inst., Nat. Inst. Health, Bethesda, MD (USA)

Electrophoresis of native proteins on agarose gels containing volatile buffers. L. Alvarez and A. Nieto.

Verff. beschreiben ein Verfahren zur schonenden Aufl6sung von Pro- teingemischen an Agarosegel, bei dem die Proteine nicht denaturiert werden. Sie verwenden Oele, die Ammoniumbicarbonatpuffer enthalten, den man sp/iter verfifichtigen kann. Nach der elektrophoretischen Tren- nung (1 - 2 h bei 4 - 5 V/cm) schneidet man das Gel in lfingliche Streifen, f/irbt mit 0,1%iger L6sung von Amidoschwarz in 50%igem Methanol, das 10% Essigs/iure enth~ilt, an und entffirbt dann 10-15 min bei 8 V/ cm. Man kann die Banden entweder aus dem Gel eluieren und abzentri- fugieren oder sie, unter nicht-denaturierenden Bedingungen, durch Ca- pillartransfer auf Nitrocellulosepapier fibertragen, hn Ietzteren Fall be- halten die Proteine ihre biologische Aktivit/it. - Anal. Lett. 22, 2737- 2745 (1989). Centro Biol. Molec. (CSIC-UAM), Univ. Auton., Madrid (E) W. Czysz

A native, affinity-based protein blot for the analysis of streptavidin heterogeneity: Consequences for the specificity of streptavidin mediated binding assays. J. Dittmer, A. Dittmer, R.D. Bruna and V. Kasche.

Commercial preparations of streptavidin, a bacterial biotin-binding protein, were analyzed by isoelectric focusing combined with an affinity- based protein blot using biotinylated, protein-saturated nitrocellulose. The colorimetrical detection of streptavidin with biotinylated alkaline phosphatase allows the selective visualization of streptavidin molecules with at least two active biotin-binding sites. Dependent on the preparation, seven to sixteen streptavidin forms were found with isoelectric points ranging from 5 to 8. Molecular weight analysis of the subunits of streptavidin showed that the observed heterogeneity was mainly due to limited proteolysis, which does not destroy the biotin-binding activity. The preparations differed also in the nonspecific reactivity of streptavidin with single-stranded DNA, bovibe serum albumin and Tween 20. - Electrophoresis 10, 762-765 (1989). Physiol. Inst. Univ., Zfirich-Irchel (CH); Techn. Univ., Hamburg-Harburg (D)

Rapid detection of proteins by enzyme-linked immunofiltration assay after transfer onto nitrocellulose membranes. J.-M. Pinon, D. Puygauthier- Toubas, H. Lepan, C. Marx, A. Bonhomme, J. Boulant, R. Geer and H. Dupont.

Enzyme-linked immunofiltration assay (ELIFA) for labeling trans- ferred proteins is an interesting and powerful technique for the rapid specific detection 05 mix) of proteins immobilized on nitrocellulose or nylon membranes (0.20 and 0.45 gin). ELIFA does not require fastidious handling of the membranes. Saturation, specific labeling and washing procedures are achieved by filtration, controlled by a monitoring unit which regulates the flow rate and ensures excellent specificity, repetition and reproducibility. The recycling by closed circuit or by repetetive inversion of the flow direction offers the advantage of reducing the volumes of expensive reagents while simultaneously increasing the sensitivity of the technique. The detection limit is at least as low as 1 - 5 ng using directly or indirectly enzymatically labelled probes. ELIFA may be extended to the identification of glycoproteins using specific ligands such as lectins or to the immunocapture of an antigen using specific antibodies immobilized on an activated membrane. ELIFA complements fast separation, by e.g., isoelectric focusing, polyacrylamide gel electrophoresis, or sodium dodecyl sulfate - polyaerylamide gel electrophoresis and accelerated electrotransfer to membranes with rapid detection reducing the total time for separation transfer and detection to less than 2 h. - Electrophoresis 11, 4 1 - 4 5 (1990). Lab. Parsitologie- Mycologie C.H.R.U., Reims (F)

Improved detection of lymphocyte membrane proteins in purified form and as a crude mixture using native and denaturing polyacrylamide gel electrophoresis by optimisation of Coomassie Brilliant Blue and silver staining. R.S. Warlow and C.C.A. Bernard.

Optimised silver staining protocols were devised for the detection of membrane proteins in purified form and as a crude mixture. These were adducted in both sodium dodecyl sulfate (SDS) and native polyacrylamide gel eletrophoresis and consisted of ethanol-acetic acid-

formaldehyde fixation, Coomassie Brillant Blue prestaining, Rapifix pretreatment, formaldehyde enhancement and finally ammoniacal silver staining. With these modifications, numerous staining problems of membrane proteins were overcome. These included reduction in background staining, enhanced detection sensitivity in native gels, elimination of negative staining and the avoidance of metallic silver deposition on the gel surface. In overcoming these problems, some factors determining the colour and stainability of membrane proteins in their native state were determined. Both the anionic Coomassie Brilliant Blue dye and SDS detergent improved the sensitivity of silver staining in native gels, and ammoniacal silver was more sensitive than neutral silver, suggesting silver staining to be a charge dependent process. - Electrophoresis 11, 53-60 (•990). Neuroimmun. Lab., Psychol. Dept., La Trobe Univ., Bundoora, Victoria (AUS)

Horizontal two-dimensional electrophoresis of cerebrospinal fluid proteins with immobilized pH gradients in the first dimension. K. Mattila, T. Pirttil~ and H. Frey.

A horizontal two-dimensional electrophoresis method with immobilized pH gradient isoelectric focusing supplemented with carrier ampholytes in the first dimension was applied to cerebrospinal fluid (CSF) proteins. About 300 protein spots could be detected on the silver- stained two-dimensional maps of CSF samples. This high-resolution method is a tool worthy of consideration for the research of CSF proteins and disease-specific changes in different neurological disorders. - Electrophoresis 11, 9 1 - 9 2 (•990). Dept. Clin. Sci. Brain Res. Center, Univ., Tampere (SF)

Essential problems in quantification of proteins following colloidal staining with Coomassie Brilliant Blue dyes in polyacrylamide gels, and their solution. V. Neuhoff, R. Stamm, I. Pardowitz, N. Arold, W. Ehrhardt and D. Taube.

Quantitative determination of stained proteins following polyacrylamide gel electrophoresis (PAGE) is of increasing interest especially since computer-aided densitometers have become available as well as recipes for sensitive and background-free staining with Coomassie Brilliant Blue dyes. However, avoidance of separation artifacts ist not the only essential prerequisite for quantitative evaluation. The local particle density of a protein in a given gel is of critical importance since it determines its stainability. Depending on local protein concentration, the dye binding to the same amount of a given protein differs considerably. Since the stainability of proteins using colloidal staining procedures, as with Coomassie Brilliant Blue dyes, is time-dependent and, in addition, also dependent on the pore size of a given polyacrylamide gel used for PAGE, calibration curves for quantitative determinations have to be prepared in polyacrylamide gels of the same composition as used for PAGE. Staining conditions also have to be identical for calibration gels and gels under analysis. - Electrophoresis 11, 101 - 117 (1990). Max-Planck- Inst. exp. Med., G6ttingen (D)

Suitability of staining techniques for the detection and quantitation of nonhistone high mobility group proteins. A. Csordas, M. Pedrini and H. Grunicke.

Three different staining techniques were compared for the detection of nonhistone high mobility group (HMG) proteins after acidic urea- polyacrylamide gel electrophoresis. Silver staining after glutaraldehyde fixation provides the highest detection sensitivity. Because of the acid solubility of HMG proteins precial care has to be taken concerning fixation. Staining with colloidal CBB G-250 according to Neuhoff et al. is superior in sensitivity and reliability of quantitation when compared with noncolloidal Coomassie Brilliant Blue R-250. High detection sensitivity and reproducibility of quantitation are prerequisites for studying the tissue-specific expression of HMG proteins. In the present study tissue-specific differences in the molar amounts of various HMG proteins in thymus and erythrocytes of the chicken are documented by application of the methods tested. - Electrophoresis 11, 118-123 (1990). Inst. Med. Chem. Biochem., Univ., Innsbruck (A)

Alternative methods for fixing and staining gliadins in polyacrylamide gels. R.L. Clements.


Staining efficiencies of Coomassie Brilliant Blue G-250 (CBB G-250) and Coomassie Brilliant Blue R-250 (CBB R-250) in various media were studied in efforts to reduce or eliminate requirements for trichloroaeetic acid (TCA). Stained gels were compared with gels stained with CBB R- 250 in 12% TCA and evaluated for overall stain and background. Be- cause of qualitative effects, stain intensities of low- and high-mobility gliadins were aIso evaluated. Results indicated gliadins are fixed under a wide range of conditions, permitting adjustment of conditions to provide optimum staining. CBB G-250 and R-250 in tap water fixed and stained most gliadins. Best results were obtained with CBB G-250 in 2% TCA, in 2% TCA containing 5% sodium sulfate, and in 2% and 5% phosphoric acid containing 5% sodium chloride or 5% sodium sulfate. Gels stained in these media were more easily observed during staining and more easily destained than gels stained in CBB R-250 in 12% TCA. - Electrophoresis 11, 123-128 (1990). USDA-ARS Soft Wheat Quality Lab., Wooster, OH (USA)

Column isoelectric focusing in natural pH gradients generated by biological buffers. N.R. Vaidya, B.P. Gothoskar and A.P. Banerji.

Using 2 or 3 simple Good zwitterionic buffers at a 16 or 18 mmol/1 final column concentration of the mixture, natural pH gradients of 4 to 8 and 3 to 9.5, respectively, were generated in a liquid LKB column. The pH gradients, stabilized by an anticonvective sucrose gradient, were linear, reproducible and stable in the electric field up to 5 h. The pH gradients were used for isoelectric focusing of a number of impure proteins such as human hemoglobin, bovine serum albumin and chicken egg white lysozyme. The protein components could be well separated in the gradient, were easily recoverd and appeared to be quite pure when analyzed by sodium dodecyl sulfategel electrophoresis. Furthermore, the pH gradient 4-- 8 was effectively used to isolate one of the acidic isozyme (pI 5.6) components of mouse liver alcohol dehydrogenase (EC 1.1.1.1) in an enzymatically active state, suggesting that the procedure does not denature proteins. The low cost, the ease with which the pH gradients are formed, their linearity, stability for a sufficient period to allow proteins to reach equilibrium and their subsequent recovery from buffer eluates should make the procedure interesting for electrofocusing of proteins. - Electrophoresis 11, 156-161 (1990). Biol. Chem. Div., Cancer Res. Inst., Parel, Bombay (IND)

Videofluorometric analysis of aging human collagen. S.L. Neal, D.R. Sell, M.P. Thomas, V.M. Monnier and I.M. Warner.

Bereits friiher wurde die Entwicklung fluorescierender Pigmente in alterndem menschlichem Collagen beobachtet, ohne dal3 deren Entste- hung und chemische Zusammensetzung bekannt war. Vor kurzem wurden zwei definierte Fluorophore aus derartigem Gewebe isoliert und einer Sequenz yon proteolytischen Aufl6sungen und chromatographischen Trennungen unterworfen. Unter Einsatz eines Videofluorimeters, der die Fluorescenzintensitfit einer Probe als Funktion verschiedener Anregungs- und Emissionswellenlfingen registriert, wurde die Fluores- cenz dieses collagenreichen Gewebes auf verschiedenen Stufen des Tren- nungsprozesses aufgezeichnet und daraus die Anzahl der fluorescieren- den Komponenten in jeder dieser Proben aufgrund ihrer Fluorescenz- spektren bestimmt. Diese Analyse zeigte, dab die unl6sliche collagenrei- che Fraktion zwei Hauptfluorophore enth/ilt, deren Spektren mit denen der isolierten Verbindungen iibereinstimmen. - Anal. Lett. 22, 2747- 2760 (1989). Dept. Chem., Emory Univ., Atlanta, GA (USA)

W. Czysz

Effects of the standardization of quantitative fluorometry on the automated evaluation of platelet antibodies. D. Gardell and M. Flagler.

An automated fluorescence invertoscope featuring a computer-controlled scanning stage with plate inserts for multiple samples, a photomultiplier tube and software controlling every function of the microscope were used to collect the fluorescence data after analog- to-digital conversion. Principal differences between this method and qualitative platelets tests include the standardization of all test reagents and the quantitative evaluation of possible autofluorescence. The automated data acquisition permitted the separate evaluation of the fluorescence and optimal fluorochrome concentrations. EDTA-anticoagulated platelets of 100 donors were incubated with serum, subsequently with fluorescein or rhodamine-treated IgG, washed, counted in PBS-glycerol,

and mounted on thin glass plates. Each plate contained 5000 ceils per test and negative and positive controls. - Anal. Chim. Acta 227, 251 - 256 (1989). Canadian Red Cross Society, Ottawa Centre, Ottawa, Ontario (CDN)

A sensitive, radiometrie assay for lysophosphatidylcholine. D.J. Dob- meyer, P.B. Corr and M.H. Creer.

To facilitate investigation of the metabolism of lysophosphatidylcholine and choline lysoplasmalogen in small quantities of tissue, a method for the quantification of these phospholipid species that is capable of accurate and reproducible analysis in samples which contain less than 1 nmol of total choline lysophospholipid was developed. The procedure employs chloroform and methanol extraction of phospholipids from isolated tissue with subsequent separation of the choline lysophospholipid fraction by HPLC. The choline tysophospho- lipids are then acetylated with [3H]acetic anhydride and the [3H]acetyl- lysophosphatidylcholine product is isolated by TLC and quantified by liquid scintillation counting. The choline lysophospholipid content in the sample is determined from a standard curve constructed from samples containing a known amount of synthetic lysophosphatidylcholine with correction for recovery based on the inclusion of [l~C]lysophosphatidylcholine as an internal standard. - Anal. Biochem. 185, 36-43 (1990). Dept. Int. Med. Dept. Pharmacol., Washington Univ., School Med., St. Louis, MS (USA)

An immunoradiometric assay for 1,25-dihydroxyvitamin D3 receptor. M.E. Sandgren and H.F. Deluca.

A ligand-independent, quantitative assay has been developed for the measurement of ],25-dihydroxyvitamin D receptor utilizing purified receptor from pig intestine as a standard and two high affinity monoclonal antibodies directed to two different epitopes on the receptor. In this assay a fixed amount of 125I-labeled antibody is incubated with a fixed amount of a second antireceptor antibody linked to biotin and increasing amounts of purified receptor protein or sample. Antibody- receptor complexes can then be immunoprecipitated with avidin- Sepharose beads and counted. This method is highly reproducible and can detect 150 pg of 1,25-dihydroxyvitamin D3 receptor in crude extr~acts with intra- and interassay coefficients of variation of 8.6 and 18.2%. The monoclonal antibodies used recognize both native and denatured receptors from several different species, including human. This immunoradiometric assay should prove useful for studies of receptor regulation, occupancy, distribution, and turnover. - Anal. Biochem. 183, 57 -63 (1989). Dept. Biochem., Univ., Madison, WI (USA)

Chromatographic determination of 7-dehydrocholesterol in human blood serum. I.N. Karinova and V.I. Dvorkin.

7-Dehydrocholesterol (7-DCH) wurde in Humanblutserum (HBS) unter Verwendung einer mit Zorbax ODS gefiillten Sfiule (250 x 4,6 mm) und Acetonitril/Isopropanol (35:65) als mobiler Phase mittels HPLC bestimmt. Gearbeitet wurde mit dem Fliissigkeits-Chromatographen ,,Altex" mit UV-Detektor (282 nm). 7-DCH liegt im HBS meistens in Form seiner Ester vor, die vor der HPLC-Analyse mit alkoholischer Kalilauge bei 45°C verseift werden miissen. 7-DCH wird danach aus dem Reaktionsgemisch extrahiert (cf. G.R. Cooper et al. : Clin. Chem. 32, 921 (1996)) und auf die beschriebene Weise bestimmt. Die quantitative Auswertung der Analyse erfolgt aufgrund der im Bereich 0 -1000 pmol/1 7-DCH linear verlaufenden Eichkurve; Nachweisgrenze 0,05 gmol/1 7-DCH. Ausffihrliche Besprechung des vorgelegten sowie der in der Literatur angegebenen Verfahren s. Original. - Zh. Anal. Khim. 44, 1902-1905 (1989) (Russisch, mit engl. Zus.fass.). Allunion Forsch.- zentrum f. prophylaktische Med., Moskau (SU) F. Jancik

Quantitative profiling of 6-ketoprostaglandine FI~, 2,3-dinor-6-ketoprostaglandine F1~¢, thromboxane B2 and 2,3-dinor-thromboxane B2 in human and rat urine by immunoaffinity extraction with gas chromatography-mass spectrometry. C. Chiabrondo, V. Pinciroli, A. Campoleoni, A. Benigni, A. Piccinelli and R. Fanelli.

The urinary metabolites of prostacyclin and thromboxane were quantitatively extracted from human or rat urine spiked with deuterated internal standards using mixed-bed columns containing immobilized anti-6-keto-PGFja and anti-TXB2 antibodies (cross-reacting with 2,3-


dinor-6-keto-PGFsz and 2,3-dinor-TXB2, respectively). The extract was directly derivatized to form pentafluorobenzyl ester, methyloxime, trimethylsilyl ether derivatives. Quantitation was performed by stable isotope dilution assay and HRGC/NICI-MS by monitoring the carb- oxylate anion (M-181) of the derivatized metabolites. The method was applied to evaluate the urinary excretion of 6-keto PGFa~, 2,3-dinor-6- keto-PGFlcz, TXB2 and 2,3-dinor-TXB3 in humans and rats. Results were in accordance with previously reported data obtained by other methods. This sensitive and selective method represents a significant advance in terms of rapidity and simplicity over other immunoaffinity/ GC/MS methods for measuring single prostanoids, such as 6-keto- PGFI~ or TXB2 since it allows profiling of a group ofmetabolites whose balance is important in several physiopathological conditions. - J. Chromatogr. 495, 1 - 11 (1989). Ist. Ricerche Farmacol. "Mario Negri", Milan (I)

Preparation and specificity of antisera for radioimmunoassay of 4- methoxyestrogen. M. Teranishi, Y. Fujih and M. Yamazaki.

4-Hydroxyestrogens are metabolized to 4-methoxyestrogens by catechol-O-methyltransferase. For radioimmunoassay of 4-methoxyestrone (4-MeOE1), asantisera were prepared in rabbits by immunization with two types of hapten-bovine serum albumin (BSA) conjugates. The antiserum A was elicited with the C-2 conjugate in which 4-MeOE1 was coupled to BSA by a Mannich reaction. Antiserum B was raised against 4-methoxyestradiol 17-hemisuccinate-BSA conjugate. The antisera A and B bound to approximately 50% of tritium-labeled 4-MeOE1 at final dilutions of 1:47600 and 1:420000, respectively. The association constants of antisera were determined as 6.1 × 109 and 4.6 x 101° M- 1 using Scatchard plots. The linearity of standard curve (log-logit plots) ranged from 10 to 1000 pg for antiserum A, while the plots were linear over the range of 2 to 1000 pg for antiserum B. The antiserum A showed cross-reactions to a considerable extent with estrone derivatives substituted at the A-ring. In contrast, the antiserum B underwent no cross-reactions with any compound except 4-methoxyestradiol (107%). - Bunseki Kagaku 38, 636-642 (1989) (Japanisch, mit engl. Zus.fass.). School Pharm., Hokuriku Univ., Kanazawa-shi, Ishikawa (J)

Simultaneous "determination of methylprednisolone and methylprednisolone 21-[8-[methyl-(2-sulfoethyl)amino]-8-oxooctanoate]sodium salt in human urine by high-performance liquid chromatography with ultraviolet detection. J.A. Shah and D.J. Weber.

The assay procedure involves stabilization of urine samples by addition of NazEDTA and ion-pair extractions of MPSO using tetraethylammonium chloride (TEAC1) as the counter ion. After extracting both drugs and internal standard into chloroform, the extract was evaporated to dryness under nitrogen. The resulting residue was reconstituted in 200- 500 gl of mobile phase and chromatographed on a IBM Cas reversed-phase column (5 gm). The mobile phase was a mixture of water/acetonitrile/isopropanol (71.2:18.8 : 10.0) containing 75 gi of 0.1 M HCI and 0.450 g of TEAC1 per liter. Propyl p- hydroxybenzoate was used as an internal standard. The extraction ef- flciencies of MP and MPSO were greater than 90% using the ion-pairing agent TEAC1. The chromatographic responses were linear up to about 200 gg/ml for MP and 80 gg/ml for MPSO and had sufficient precision and accuracy to provide quantitative data from human urine. The assay detection limit was about 8 ng/ml for MP and 25 ng/ml for MPSO in human urine. - J. Chromatogr. 496, 245 - 254 (1989). Drug Metabolism Res., Upjohn Co., Kalamazoo, MI (USA)

GS-MS assay for 9~t,15(S)-dihydroxy-ll-oxo-thromba-5(Z),13(E)-dien- 1-oic acid. A. Ferretti, V.P. Flanagan and E.J. Maida.

The title compound (TXB2-M) is a quantitative index of thromboxane A2 synthesis in the human. We developed a method for its determination in urine based on the use of the 13C_labele d methyl ester derivative of the analyte as internal standard and GC-EIMS. The interassay coefficient of variation (CV) was 5.3% (N = 4) and the intraassay CV ranged from 2.6 to 8.2% (N= 3). The equation of the regression curve correlating the amounts added and recovered was Y = 0.932 x + 3.99 (R = 0.9947). The relative recovery of TXB2 from nine urine specimens was 99.8_+ 2.8% (mean + SEM). The mean (_+ SD) 24-h output in six healthy male sub- jects was 1371 _+ 307 ng, and in six females it was 1176_+418 ng.

Concentrations as low as 200 pg/ml of urine can easily be measured with this procedure if one uses 50 ml of urine for the analysis. - Anal. Lett. 22, 2323 -2334 (1989). Lipid Nutrit. Lab., Human Nitrition Res. Center, Beltsville, MD (USA)

Spectrophotometric determination of thyroxine sodium with p-benzoquinone. S.Z. E1-Khateeb.

A simple, sensitive and selective spectrophotometric method has been developed for the determination of thyroxine sodium. It is based on a reaction with excess of p-benzoquinone in ethanol (95%) whereby 1 : 1 (thyroxine sodium: quinone) coloured product is obtained, which has an apparent molar absorptivity of 2.911 x 1031 tool- i cm- 1 and Beer's law is obeyed over the range of 40-200 gg ml 1. When applied to tablets labelled to contain 100 gg, the proposed method gave mean recoveries of 99.•3 _+ 0.36% for different amounts of added authentic drug. - Anal. Lett. 22, 2223-2232 (•989). Pharm. Chem. Dept., Coll. Pharm., King Saud Univ., Riyadh (Saudi Arabia)

Fluorescent enzyme immunoassay of free thyroxin using glucose oxidase as enzyme label. H. Arakawa, M. Maeda and A. Tsuji.

A fluorescent enzyme immunoassay for free thyroxin using glucose oxidase as the label enzyme has been developed. Double antibody solid phase method was used. After separation of bound and free fractions the glucose oxidase activity was measured using a coupled enzyme procedure: glucose and horseradish peroxidase were used as the substrate and coupled enzyme, respectively. Hydrogen peroxidase generated from glucose was determined by the fluorophotometric method using p- hydroxyphenylpropionic acid as a substrate. The proposed fluorescent enzyme immunoassay is uninfluenced by thyroxin-binding globulin or by albumin. Free thyroxin values in serum determined by the proposed method correlated well with those obtained by the equilibrium dialysis method (serum: r=0.93). Free thyroxin in a dried blood filter paper disc (3 mm in diameter) could be assayed by this method. The mean variabilities (RSD) of within and between assays were 9.6% and 6.9% for sera and 7.6% and 9.1% for dried blood samples, respectively. The measurable range of free thyroxin was from 0.05 to 5 ng/dl. - Anal. Sci. 6, 3 3 - 37 (I990). School Pharm. Sci., Showa Univ., Tokyo (J)

Elimination of human chorionic gonadotropin in sandwich enzyme immunoassay for human thyroid-stimulating hormone in serum. K. Tanaka and E. Ishikawa.

Verff. beschreiben eine Methode zur Ausschaltung des menschlichen Choriongonadotropins (hCG) beim Sandwich-Enzymimmunoassay des menschlichen Thyroid-stimulierenden Hormons (hTSH) in Blutserum. Man lfiSt hTSH im Serum, das daneben auch hCG enth~ilt, mit Dinitro- phenyl-monoklonalem Mfiuse-Anti-hTSH-~-Subunit-IgG1 reagieren. Den zwischen Dinitrophenyl-IgG1 und hTSH gebildeten Komplex ffingt man an Polystyrolkiigelchen ab, die mit affinit/itsgereinigtem Kanin- chen-(anti-dinitrophenyl-BSA)-IgG fiberzogen sind. Durch Waschen der Polystyrolkfigelchen wird danach das hCG weitgehend eliminiert. An- schlieBend lfigt man den Komplex auf den Kiigelchen mit affinitfitsgerei- nigtem Kaninchen-Anti-hCG-Fab'-Peroxidase-Konjugat reagieren und wfischt abermals. Die weitere hTSH-Bestimmung erfolgt wie fiblich. Einzelheiten werden in der Arbeit angegeben. - Anal. Lett. 22, 2471 - 2483 (1989). Dept. Biochem., Med. Coll., Kiyotake, Miyazaki (J)

W. Czysz

Enzymatic fluorimetric determination of ursodeoxycholic acid in urine using Clostridium absonum 7fl-hydroxysteroid dehydrogenase. E.S. Liani- dou, D.S. Papastathopoulos and P.A. Siskos.

A simple and rapid enzymatic fluorimetric method for the determination of ursodeoxycholic acid (UDCA) and its glycine (GUDCA) and taurine (TUDCA) conjugates in urine has been developed. Octadecyl- silane-bonded silica cartridges (Sep-Pak ClS) are used for the solid-phase extraction of bile acids (BA) from urine samples. The method is based on the fluorimetric monitoring of NADPH formed via the reaction of 713-hydroxylated BA (7J3-BA) with J3-nicotinamide adenine dinucleotide phosphate (J3-NADP ÷) catalysed by 7J3-hydroxysteroid dehydrogenase (7[3-HSD) isolated from Clostridium absonum cultures and purified by affinity chromatography. The method has a limit of detection of 2 gmol/ 1, within-run precision from 8.3% to 5.3% and between-run precision


from 12% to 1.8% for low and high concentrations resp. The recovery of ursodeoxycholic acid added to urine samples was about 98% (range 88-110%). - Anal. Lett. 22, 2265-2280 (1989). Dept. Chem. Anal. Chem. Lab., Univ., Athens (GR)

Optical surface methods for detection of nucleic acid binding. C.F. Mandenius, A. Chollet, M. Mecklenburg, I. Lundstr6m and K. Mos- bach.

Verff. beschreiben einen Nachweis ffir die DNA-Bindung und -Hybri- disierung durch pseudo-Brewster-Winkelrefiektrometrie und Ellipsome- trie. Die DNA wird an ebene Siliciumoberflfichen angelagert, die vorher mit einer Nitrocelluloseschicht yon 150 A Dicke oder einer Monoschicht Aminosilan fiberzogen wurden. Als Bindungsmittler zwischen diesen modifizierten Schichten und DNA benutzte man Poly-L-lysin. Gemessen wird der Verlauf der Reassoziierung durch Reflektometrie. Ffir Polynu- cleotide yon 0 ,5-1 ,0 kb wurde eine Reassoziationszeit von annfihernd I Stunde festgestellt. - Anal. Lett. 22, 2961-2973 (1989). Dept. Pure Appl. Chem., Chem. Center, Univ., Lund (S) W. Czysz

A disposable hypoxanthine sensor based on a micro oxygen electrode. M. Suzuki, H. Suzuki, I. Karube and R.D. Schmid.

Verff. konstruieren einen einfach verffigbaren Mikroenzymsensor zur Bestimmung yon Hypoxanthin. Sic verwenden dazu eine Mikro-Sauer- stoffelektrode vom Clark-Type und Xanthinoxidase, die nach einem beschriebenen Verfahren an der Elektrodenoberfi/iche immobilisiert wird. Diese Elektrode zeigt sehr gutes Ansprechverhalten fiir Hypoxan- thin, das als Indicator ffir die Frische yon Fischen im Lebensmittelhandel benutzt wird. Der Bestimmungsbereieh liegt zwischen 6,7 und 180 gM Hypoxanthin. - Anal. Lett. 22, 2915- 2917 (1989). GBF-Ges. Biotech- nol. Forsch., D-3300 Braunschweig; Fujitsu Labs. Ltd., Atsugi (J)

W. Czysz

A highly sensitive enzymatic assay method for hypoxanthine estimation based on the use of an oxygen electrode. J.M. Kim, M. Suzuki and R.D. Schmid.

Zur Bestimmung yon Hypoxanthin wird ein hochempfindliches enzy- matisches Verfahren unter Verwendung von Xanthin-Oxidase und dem Einsatz einer Clarkschen Sauerstoffelektrode beschrieben. Das Verfah- ten, das auf der Messung des Sauerstoffverbrauchs durch Xanthin- Oxidase beruht, wurde bereits frfiher durch Zugabe von Sulfit dahinge- hend verbessert, dab der stimulierte Sauerstoffverbrauch eine Erh6hung der Empfindlichkeit bedeutet. Dabei trat jedoch eine wachsende Unge- nauigkeit der Methode dadurch auf, dab es zu einer signifikanten Erh6- hung auch der nichtenzymatischen Oxidation yon Sulfit kommt. Dieser Nachteil wird nun durch die Zugabe von EDTA zur Reaktionsl6sung weitgehend ausgeschaltet. Mit dieser Modifikation werden Empfindlich- keiten erreicht, die im Bereich der Chemiluminescenzverfahren liegen. Hypoxanthin kann im Bereich 5 nM bis 100 pM mit Responsezeiten von 4 min oder weniger (bei 30°C)bestimrrit werden. - A n a l . Lett. 22, 2433 - 2443 (1989). Ges. f. Biotechnol. Forsch. (GBF), D-3300 Braunschweig

W. Czysz

3,4-Dinitrophenyl N-acetyl-~-D-glucosaminide, a synthetic substrate for direct spectrophotometric assay of N-acetyl-[3-D-glucosaminidase or pC_ acetyl-[3-D-hexosaminidase. T. Yagi, R. Hisada and H. Shibata.

3,4-Dintrophenyl N-acetyl-[3-D-glucosaminide (3,4-dnpClcNAc) was synthesized and proposed as an artificial substrate for N-acetyl-[3-D- glucosaminidase (EC 3.2.1.30) and N-acetyl-[3-D-hexosaminidase (EC 3.2.1.52) (collectively abbreviated as NAGase). 3,4-dnpGlcNAc is water soluble and is fairly stable in aqueous medium. 3,4-Dinitrophenol released from 3,4-dnpGlcNAc by NAGase absorbs light of 400 nm at pH near 5, where the activity of urinary NAGase is assayed for diagnostic use. Direct and sensitive spectrophotometric assay of NAGase is, thus, possible using 3,4-dnpGlcNAc as an artificial substrate by monitoring the increase of A400 due to the release of 3,4-dinitrophenol in a thermostated spectrophotometer. -- Anal. Biochem. 183, 245--249 (1989). Dept. Chem. Chem. Educ., Univ., Shizuoka (J)

An enzyme-linked immunosorbent assay for N-aeetylglucosaminyltrans- ferase-V. S.C. Crawley, O. Hindsgaul, G. Alton, M. Pierce and M.M. Palcic. '

The development of an enzyme-linked immunosorbent assay (ELISA) for uridine 5'-diphospho-N-acetylglucosamine:emannoside [31 ~ 6 N- acetylglucosaminyltransferase (GnT-V) is reported. The assay quantitates the enzymatic conversion of the specific synthetic GnT-V acceptor GlcNAc[31 ~2Mancd ~6Man[3-R (5) to the product GlcNAc[31 -~ 2[GIcNAc-[31 ~ 6]Maned --* 6Man[3-R (6) when these oligosaccharide structures were covalently attached to bovine serum albumin which was then coated on microtiter wells. Conversion of 5 to 6 was detected using a polyclonal antiserum raised against the product 6 and from which antibodies cross-reacting with acceptor 5 had been removed by affinity adsorption. GnT-V activity detected by ELISA was linearly proportional to both enzyme concentration and time under appropriate experimental conditions where 50 - 300 fmol of product was formed per microtiter well. GnT-V activity could be measured by ELISA in Triton X-100 extracts of hamster kidney acetone powder and in human serum. The twofold increase in GnT-V activity which is known to accompany Rous sarcoma virus transformation of baby hamster kidney cells could also be quantitated using the ELISA. - Anal. Biochem. 185, 112-117 (1990). Dept. Food Sci., Univ. Edmonton, Alberta (CDN); Dept. Cell Biol. Anatomy, Univ., School Med., Miami, FL (USA)

Head-space chromatography in determination of enzymatic activity. Microdetermination of the urinary kallikrein as arginine esterases. R. Curini, S. de Angelis Curtis, G. D'Ascenzo and A. Lagan~c

Viele enzymatische Reaktionen ffihren, unmittelbar oder fiber Stufen- sequenzen, zu flfichtigen, d.h. gasf6rmigen Produkten. Dieses Verhalten nutzt man zur Entwicklung einer Methodik, bei der indirekt die enzymatische Aktivit/it des betreffenden Enzyms mit Hilfe der Head-space- Gaschromatographie bestimmt werden kann. Als Beispiel dient die Be- stimmung von Kallikrein als Arginin-Esterase in Urin. Man verwendet N~-Acetyl-L-phenylalanyl-L-arginin-Ethylester als Substrat und bestimmt das sich bei der Inkubation von 10 rain bei 30°C entwickelnde Ethanol. Die Reaktion wird danach dutch einen Inhibitor (eine L6sung yon 1,44 g Zinksulfat-Heptahydrat + 0,69 g Natriumnitrit in 10 ml dest. Wasser) gestoppt, das GeffiB mit einer Head-space-Verschlul3kappe luftdicht abgeschlossen, 30 rain bei 60°C im Thermostaten erw/irmt (urn den Verteilungskoeffizienten zwischen Dampf- und Flfissigphase zu optimieren) und im AnschluB daran das Ethanol gas-chromatographisch bestimmt. Das Verfahren brachte sehr gute Ergebnisse hinsichtlich Rich- tigkeit und Prfizision mit Wiederfindungen zwischen 95,0 und 98,0%. Es wurde an wfigrigen L6sungen und Urinproben getestet. - Talanta 36, 1087-1090 (1989). Dept. Chem. Sci., Univ., Camerino (I)W. Czysz

Fluorometric determination of serum cholinesterase activity. F. Kusu, T. Tsuneta and K. Takamura.

The fluorometric assay using 3-(p-hydroxyphenyl)-propionic acid (HPPA) was adapted for the determination of serum cholinesterase (ChE) activity in serum and plasma. The combined use of ChE and choline oxidase promotes the degradation of benzoylcholine to generate hydrogen peroxide. The resulting hydrogen peroxidase can be determined fluorometrically through the reaction with HPPA in the presence of peroxidase. The detection limit of ChE activity was 10 IU/1. The relative standard deviation of the activity in serum was 1.7%. The present method was also applied to the determination of ChE activity in dried blood samples on filter paper with good results. - Bunseki Kagaku 39, 115-121 (1990) (Japanisch, mit engl. Zus.fass.). Coll. Pharm., Tokyo (J)

Immunochemical detection of microqnantities of bacterial formate dehydrogenase. A.V. Bogdanova, V.I. Tishkov, T.V. Cherednikova, A.G. Galkin and A.M. Egerov.

Zum Nachweis yon NAD +-abh[ingiger Formiat-Dehydrogenase (EC 1.2.1.2, FHD), die aus dem methylotrophen Bacterium Pseudomonas sp. 101 isoliert wurde, werden zwei immunchemische Methoden entwik- kelt: 1. die dot-blot-Analyse unter Verwendung yon polyklonalen Kanin- chen-Antik6rpern; 2. die indirekte kompetitive ELISA-Methode unter Verwendung von poly- oder monoklonalen M/iuse-Antik6rpern. Bei der ersten Screeningmethode erreicht man eine Empfindlichkeit von 5 bzw. 1 pg Enzym je Probe, wenn man Anti-Kaninchen-Antik6rper/Meerret- tich-Peroxidase-Konjugat bzw. biotinylierte Anti-Kaninchen-Antik6r- per/Avidin-Peroxidase-Konjugat verwendet. Das zweite Verfahren zur


exakten Bestimmung der FHD-Konzentration in zellfreien Extrakten ausgew/ihlter rekombinanter Klone durch ELISA erreicht eine Empfind- lichkeit yon 1 ng bakterielle EHD je Probe. - Anal. Lett. 22, 2761 - 2770 (1989). A.N. Bach Inst. Biochem., USSR Acad. Sci., Moskau (SU)

W. Czysz

Direct assay of glycosphingolipid glycusyltransferase activities on thin- layer chromatogram. X. Gu, T. Gu and R.K. Yu.

A modified method for the determination of glycosphingolipid glycosyltransferase activity using HPTLC plates has been developed. An acceptor glycosphingolipid was chromatographed on an HPTLC plate and was incubated with an enzyme mixture and an appropriate radioactive sugar nucleotide. After incubation, the plate was washed with phosphate buffer and 2% Tween 80. The radiolabeled reaction product was scrapped off the plate and the radioactivity determined using a liquid scintillation counter or, alternatively, the plate was exposed to an X-ray film to reveal the radioactive product. We have used this assay method to determine the activities of rat brain cytidine 5'-monophosphate-N- acetylneuraminic acid: LacCer-, GM3-, GM1-, or GD3-sialyl- transferases: This method is sensitive, fast, and reliable and is capable of assaying simultaneously the acitivities of glycosyltransferases with multiple acceptor specificity. It should be useful in monitoring the enzyme activities present in various column fractions during chromatographic fractionation of glycosyltransferase with different substrate specificities. - Anal. Biochem. 185, 151-155 (1990). Dept. Biochem. Mol. Biophysics, Med. College, Richmond, VA (USA); Dept. Biochem., Med. Univ., Shanghai (RC)

Determination of total (Na + + K ÷)-ATPase activity of isolated or cultured cells. Z. Xie, Y. Wang, M. Ganjeizadeh, R.McGee, Jr. and A. Askari.

The aim of this work was to determine if the total (Na + + K +)-ATPase of the plasma membrane of a cell population could be assayed without cell homogenization and partitial purification of the enzyme. Several types of intact cells that were placed in an assay medium containing MgATP, Na +, and K + hydrolyzed little or none of the added ATP. When the cells were pretreated with the ionophore alamethicin and then placed in the assay medium, they exhibited an ouabain-sensitive (Na + + K +)-ATPase activity that increased and reached a limiting value with increasing alamethicin concentration. Since alamethicin did not increase the activity of the purified membrane-bound (Na++K+) - ATPase, its effects on the intact ceIIs are probably due to the formation of large channels within the plasma membrane that allow the free access of the components of the assay medium to the intracellular domains of (Na + + K +)-ATPase. Utilizing whole cells treated with alamethicin, total (Na++ K +)-ATPase activity was determined in clonal pheochromocy- toma cells (PC12), neuroblastomaxglioma hybrid ceils (NG108-15), and myocytes isolated from adult and neonatal rat hearts. With the use of this whole-cell assay, the ouabain sensitivities of the enzymes in adult and neonatal rat heart myocytes were determined and found to be the same as those that have been determined with the use of partially purified enzymes. - Anal. Biochem. 183, 215-219 (1989). Dept. Pharmacol. Med. College, Toledo, OH (USA)

Optimization of gradients in anion-exchange separations of oligonu- eleotides using computer-assisted retention prediction and a high-performance liquid chromatographic simulation system. Y. Baba and M.K. Ito.

A computer-assisted retention prediction system which is an alternative to computer simulation is demonstrated to be an efficient tool for finding optimum gradients in anion-exchange separations of oligonucleotides. The effect of the gradient profile on the resolution is illustrated by computer simulation in the visualization of simulated chromatograms by changing the variables for the gradient profile. A convex gradient was found to be more effective for the separation of high-molecular- weight oligonucleotides than a linear gradient which has been widely used, An increase in the gradient time also improved the resolution. Recommendations are presented for an approach to maximize the resolution and to minimize the analysis time in the anion-exchange HPLC of oligonucleotides. -- J. Chromatogr. 485, 647-655 (1989). Chem. Lab., Fac. Educ. Univ., Oita (J)

Reversed-phase liquid chromatographic retention and selectivity surfaces. lI. Deoxyribonucleosides. E. Grushka, N.-I. Jang and P.R. Brown.

By plotting capacity factors and selectivity factors as functions of temperature and pH or methanol concentration of the mobile phase, retention and selectivity surfaces of four deoxyribonucleosides were generated. Although changes in the methanol content had little effect on selectivity, changes in pH and temperature could be used to improve selectivity. However, changes in pH or temperature can be coupled with changes in methanol concentration to optimize the analysis time. In addition, by using lines of constant analysis time (isochrons), it was found that several sets of conditions will result in nearly identical retention times. These isochrons can be used to optimize the resolution of the solutes. - J. Chromatogr. 485, 617-630 (1989). Dept. Inorg. Anal. Chem., Hebrew Univ., Jerusalem (IL); Dept. Chem., Univ., Kingston, RI (USA)

Evaluation of fluorescent and colored phosphatidylcholine analogs as substrates for the assay of phospholipase As. H.S. Hendrickson, K.J. Kotz and E.K. Hendrickson.

Two fuorescent phospholipid analogs, 1-O-{12-(2-naphthyl)-dodec- 11-enyl}-2-O-decanoyl-sn-glycero-3-phosphocholine and dansyl-PC [rac- l-O-( N-dansyl-11-amino- a-undecyl)-2-O-decanoyl-glycero- 3-phosphocholine], and a red-colored analog, dabsyl-PC [rac-l-O-(N-dabsyl- 11-amino- 1-undecyl)-2-O-decanoyl-glycero-3-phosphocholine], were evaluated as substrates for the assay of phospholipase A2 (PLA2) (Cro- talus adamanteus). The assay reaction was monitored by separation of the fluorescent or colored substrate and product by TLC and quantitation by fluorescence or absorption scanning. All three substrates gave similar (within an order of magnitude) activities with PLA2. Dansyl-PC was best suited to this TLC assay. Dabsyl-PC was less sensitive to detection by absorbance, but had the advantage of being red colored and readily detected by the unaided eye. - Anal. Biochem. 185, 80 -83 (1990). Dept. Chem., St. Olaf College, Northfield, MN (USA)

Analysis of pirprofen in cerebrospinal fluid, plasma, and synovial fluid by high-performance liquid chromatography with electrochemical detection. L. Zecca, P. Ferrario, R. Pirola, F. Zambotti, N. Zonta and F. Fraschini.

Pirprofen, eine antiinflammatorisch wirksame Substanz, wird in Plas- ma, Cerebrospinalfltissigkeit (CSF) und Synovialflfissigkeit (SF) nach HPLC-Trennung durch elektrochemische Detektion mit einer ,,glassy carbon" Elektrode und Ag/AgCI-Referenzelektrode bestimmt. Dazu werden 500 gl der KSrperfliissigkeiten (Plasma und SF mit Wasser 1:10) verdfinnt) mit i ml 1 M Phosphors~iure und 5 ml Dichlormethan versetzt und 10 min extrahiert. AIs interner Standard dient p-Hydroxyphenylbu- tazon. Nach Zentrifugation werden 4 ml der org. Phase entnommen und mit Stickstoff zur Trockne gedampft. Der Riickstand wird in 100 gl mobiler Phase gel6st, davon 5 - 20 gi in den Chromatographen injiziert. Chromatographiebedingungen." Sfiule (150 x 4,6 ram) mit Erbasil C-18 (5 gin) (Carlo Erba, Mailand); mobile Phase: Acetat-Puffer (0,027 M Na- Acetat + 0,023 M Essigs~iure, pH 3,0 mit H3PO4)/Acetonitril (57:43); Flieggeschw. : 2~0 ml/min~; Mel3potential: + 850 inV. Linearitfit der Eich- geraden: 1 -500 ng/ml bei CSF, 0 ,25-40 gg/ml bei Plasma und SF; untere Erfassungsgrenze: 0,1 - 0,2 ng/ml bei CSF und 1 ng/ml bei Plasma und SF. Acetylsalicyls~iure, Salicylsfiure, Diclofenac, Acetaminophen, Indomethacin, Naproxen, Ketophen und Tiaprofens/iure stSren nicht bei der Bestimmung. - J. Pharm. Sci. 78, 776-779 (1989). Ist. Tecn. Biomed. Avanzate, Milano (I) W.H. Mennicke

High-performance liquid chromatographic assaY of diltiazem and six of its metabolites in plasma: Application to a pharmacokinetic study in healthy volunteers. P.K.F. Yeung, T.J. Montague, B. Tsui and C. McGregor.

Diltiazem und sechs durch Entacetylierung, Entmethylierung und N- Oxidation entstandene Metaboliten, die z.T. ebenfalls pharmakologisch wirksam sind, werden nach Extraktion aus Humanplasma durch HPLC getrennt und vermessen. Dazu werden 2 ml Plasma mit 0,1 ml (600 ng) Imipramin (interner Standard, in Methanol) und 0,2 ml 10%iger Ammoniumearbonati6sung (pH 7,8) versetzt und mit 5 ml Methyl-t- butylether extrahiert. Nach Zentrifugation wird die org. Phase entnommen und die w/iBr. Phase mit 5 ml Dichlormethan erneut extrahiert. Die vereinigten org. Phasen werden bei 50°C mit Stickstoff zur Trockne gedampft. Der Rfiekstand wird in 0,1 ml 0,01 M HC1 gelSst, davon werden 3 - 30 gl in den Chromatographen injiziert. Chromatographiebe- dingungen: Sfiule (250 × 4,6 ram) mit Ultrasphere-ODS (5 ~m); mobile


Phase: Methanol/0,04 M Ammoniumacetat/Acetonitril (40:36:24) mit 0,04% Triethylamin (pH 7,3 mit Eisessig); FlieBgeschw.: 1,2 ml/min; MeBwellenlfinge: 237 rim. Bei genauer Einhaltung dieser Bedingungen sind Diltiazem und seine Metaboliten gut voneinander getrennt (Chro- matogramme sind abgebildet). Die Linearit/it der Eichkurven erstreckt sich yon 2 bis 300 bzw. 400 ng/ml, die unteren Erfassungsgrenzen liegen bei 2,5 ng/ml, ffir den N-Oxidmetaboliten bei 5 ng/ml. - J. Pharm. Sci. 78, 592-597 (1989). College Pharm., Univ., Halifax (CDN)

W.H. Mennicke

Determination of methylguanidine in plasma and urine by high-performance liquid chromatography with fluorescence detection following post- column derivatization. V.K. Boppana, G.R. Rhodes and D.P. Brooks.

Ein HPLC-Verfahren zur Bestimmung yon Methylguanidin in biologischen Flfissigkeiten wird entwickelt. Methylguanidin und Ethylguanidin als interner Standard werden aus den mit 1 tool/1 NaOH auf pH 11 gebrachten Plasmaproben fiber eine CBA-Extraktionss[iule isoliert. Die Sfiule wird mit Wasser gewaschen und mit 1% Trifluoressigs~iure in Methanol eluiert. Der Rfickstand des eingedampften Extraktes wird in Methanol/Monochloressigs/iurepuffer (15:85) eluiert und dann auf einer Ultrasil Kationenaustauschers/iule mit Methanol/Monochloracetat (15: 85) als mobiler Phase chromatographiert. Urinproben k6nnen nach Verdiinnung direkt auf die Ultrasil-S~iule injiziert werden. Die postcolumn-Derivatisierung des Methylguanidins wird mit alkalischem Ninhy- drinreagens ausgeffihrt und das resultierende fluorescierende Produkt on-line bei 390/470 nm nachgewiesen. Dieses spezifische, empfindliche, reproduzierbare Verfahren weist eine Nachweisgrenze von 1 ng/ml in Plasma und von 100 ng/ml in Urin auf. Die Eichkurven sind von 1 - 1000 ng/ml in Plasma und yon 0,1600 gg/ml in Urin linear. - Anal. Biochem. 184, 213-218 (1990). Dept. Drug Metabolism., Dept. Phar- macol., Smith Kline & French Lab., King of Prussia, PA (USA)

R.H.S.

. Analysis of 2-cyano-l-methyl-3-[4-(4-methyl-6-oxo-l,4,5,6-tetrahydropyridazin-3-yl)phenyl]guanidine in dog plasma by liquid-solid extraction and reversed-phase high-performance liquid chromatography. J.C. Pearce, W.J. Leavens and R.D. McDowall.

A method for the determination of 2-cyano-l-methyl-3-[4-(4-methyl- 6-oxo- 1,4,5,6-tetrahydropyridazin-3-yl)phenyl]guanidine (SK&F94836, 1) in plasma is presented. The method involves liquid-solid extraction of the drug by C1~ cassettes, with subsequent elution by an AASP LC module for determination by HPLC with UV detection. The assay is rapid, precise, accurate, and specific. The between-day CV values over the concentration range 50-500 ng/ml are 4% or less; this rises to 8% at 25 ng/ml. The corresponding between-day bias is < 1% over the same range of concentrations. The limit of quantification is 25 ng/ml and the assay can be used for measuring 1 in samples from preclinical studies following either oral or intravenous administration of the compound. - J. Pharm. Sci. 78, 874-876 (1989). Dept. Drug Anal., Smith Kline French Res., Ltd., Welwyn, Herts. (GB)

Simultaneous determination of propranolol enantiomers in plasma by high- performance liquid chromatography with fluorescence detection. C. Prakash, R.P. Koshakji, A.J.J. Wood and I.A. Blair.

Die beiden Propranolol-Enantiomere im Plasma lassen sich nach Deri- vatisieren mit (-)-Menthylchloroformat und HPLC-Trennung simultan bestimmen. Dazu wird 1 ml Plasma mit 125 ng (+)-Flecainid in 50 gl Methanol, mit I ml 1 M NaOH und mit 8 ml 1% Butan-(a)-ol in n- Hexan versetzt, 3 min intensiv geschiittelt und 5 min zentrifugiertl Von der organischen Phase werden 7 ml entnommen und bei 50°C mit Stick- stoff zur Trockne gedampft. Der Rfickstand wird in 100 gl 0,4% Tri- ethylamin in Acetonitril/Methanol (1:1) gel6st und naeh Zugabe yon 50 gl 0,023 M (-)-Menthylchloroformat in Acetonitril 15 rain kr/iftig durchmischt. AnschlieBend werden davon Aliquots in den Chromatogra- phen injiziert. Chromatographiebedingungen: S/iule (250 x 4,6 ram) mit Spherisorb ODS-2 (5 gin); mobile Phase: Methanol/Wasser (89:11); FlieBgeschw. : I ml/min; Anregung: 228 nm, Emission: Kantenfilter von 340 rim. Unter diesen Bedingungen erscheint (-)-Propranolol vor (+)- Propranolol. Die Eichkurve ffir beide Enantiomere ist yon 2 ,5-100 ng/ ml linear, untere Erfassungsgrenze: 1 ng/ml. -- J. Pharm. Sci. 78, 7 7 1 -

775 (1989). Dept. Pharmacol. Med., Vanderbilt Univ., Nashville, TN (USA) W.H. Mennicke

Determination of saterinone in plasma by high-performance liquid chromatography. M. Rudolph.

Ein empfindliches Verfahren zur Bestimmung des zur Behandlung yon Herzinsuffizienz eingesetzten neuen Wirkstoffs Saterinon wird entwik- kelt. Zur Bestimmung in Plasmaproben werden diese mit einem struktur- verwandten internem Standard versetzt, alkalisch gemacht und mit Di- chlormethan zentrifugiert. Der Oberstand wird eingedampft, der Rfick- stand in tert.-Butylmethylether aufgenommen und 0,01 tool/1 HC104 zugesetzt. Nach Zentrifugation wird die wS.Brige Phase auf einer Spheri- sorb ODS II-S~iule mit einer mobilen Phase aus 1,92 g Natrium-J- pentansulfonat in 500 ml Wasser + 300 ml 0,01 tool/1 HC104 + 300 ml AcetonitriI + 50 ml Tetrahydrofuran chromatographiert. Der fluorime- trische Nachweis wird bei 345/435 nm ausgeffihrt. Lineare Eichkurven werden yon 0,25-100 ng/ml erhalten, der Variationskoeffizient liegt zwischen 1 und 2%. Die Nachweisgrenze wird mit 0,18 ng/ml angegeben. Dieses schnelle Verfahren kann ffir eine groBe Anzahl yon Proben zur pharmakokinetischen Untersuchung eingesetzt werden. - J. Chroma- togr. 497, 342-348 (1989). Beiersdorf AG R&D Pharma, Biochem. Dept., D-2000 Hamburg 20 R.H.S.

High-performance liquid chromatographic procedure for the determination of clozapine, haloperidol, droperidol and several benzodiazepines in plasma. D. Wilhelm and A. Kemper.

Zur Bestimmung von Clozapin in Kombination mit Haloperidol, Dro- peridol und anderen Benzodiazepinen, wie sie zur Behandlung von Schi- zophrenie getestet werden, werden die Plasmaproben mit Clonazepam als internem Standard und mit 0,5 mol/1 K2HPO4 versetzt, fiber eine Silica 100 RP-18 Extraktionssfiule gegeben, die mit Wasser gewaschen und mit Methanol eluiert wird. Der Rfickstand des eingedampften Eluats wird in Methanol/Phosphatpuffer aufgenommen und auf einer Silica 100 RP-18-Sfiule mit einem Gradienten yon 1 ,5-10% 2-Propanol in 0,05 tool/1 Phosphatpuffer (pH 2,9)/Ethanol/Acetonitril (70: 22: 8) chromatographiert. Der Nachweis wird bei 254 und 226 nm durchgeffihrt. Der Extraktionsschritt dauert ca. 15 rain und die HPLC-Trennung 20 rain. Die Nachweisgrenze wird mit 450 pg/ml angegeben. - J. Chroma- togr. 525, 218-224 (1990). Dept. Clin. Neurochem. Anal., Centr. Clin. Psych. Neurol., DDR-Berlin 1141 R.H.S.

Determination of nomifensine in rat brain by high-performance liquid chromatography with fluorescence detection. V. D'Aranno, A. Mancinelli, F. Borsini, M. Furio and A. Meli.

Ein einfaches Verfahren zur Detektion des Antidepressivums Nomi- fensin in Him wird beschrieben. Dazu werden die in Na2HPO4-Puffer (pH 9,2) homogenisierten Proben mit einer methanolischen L6sung yon Prazosin als internem Standard versetzt. Dann wird mit Benzol extrahiert. Nach Zentrifugation wird die organische Phase in 0,1 tool/1 HC1 rfickextrahiert und nach Alkalisierung erneut in Benzol extrahiert. Der Rfickstand des Extraktes wird in mobiler Phase aufgenommen und auf einer gBondapak VC18-Sfiule mit 0,01 tool/1 Na2HPO4 Puffer (pH 9,2)/ Acetonitril/Nonylamin (69,999:29,999:0,002) chromatographiert. Der Nachweis wird fluorimetrisch bei 292/360 nm ausgeffihrt. Im Bereich yon 5-2000 ng/g Gewebe erhfilt man eine lineare Eichkurve. - J. Chromatogr. 525, 2 3 4 - 239 (1990). Dept. Pharmacol., ,,Menarini Ricer- che Sud", Pomezia, Rom (I) R.H.S.

Enzymatic cycling assay for phenylpyruvate. A.J.L. Cooper, L.K.H. Leung and Y. Asano.

Enzymatic cycling assays for the determination of L-phenylalanine and phenylpyruvate in deproteinized tissue extracts are described. Assay 1 couples glutamine transaminase K with L-phenytalanine dehydrogenase. Assay 2 combines phenylalanine dehydrogenase, L-amino acid oxidase, and catalase. In both assays, tyrosine and some other amino acids (or their ~-keto acid analogs) can replace phenylalanine (or phenylpyruvate) to a small extent. Thus, if phenylalanine is to be measured a correction must be made for the nonspecificity of the reaction. By remov- ing phenylalanine on a cation-exchange column it was possible to measure phenylpyruvate in tissue extracts. Concentrations of phenylpyruvate (gm01/kg) in normal rat liver, kidney, and brain were 2.1 _+ 1.1 (n=8), 1.8 _+ 0.4 (n=4), and 3.3 _+ 0.6 (n=4), respectively. -- Anal. Biochem.


183, 210-214 (1989). Dept. Biochem. Neurol., Cornell Univ., Med. College, New York, NY (USA); Sagami Chem. Res. Center, Sagamihara, Kanagawa (J)

Gas-liquid chromatographic method for routine detection of plasma sul- fo-, gloco-, and free 3-methoxy-4-hydroxyphenylglycol. J.E. Piletz and A. Halaris.

Das erste Stoffwechseiprodukt des Norepinephrins (NE) im Zentral- nervensystem ist 3-Methoxy-4-hydroxyglykol (MHPG), und Vanillyl- mandelsfiure ist das erste Stoffwechselprodukt des Norepinephrins in peripheren Geweben. Es wird eine Methode zur Messung der Sulfatase- Gluco- und freien Plasmafraktionen (MHPG) beschrieben. Arbeitsweise. Eine Sulfataseeinheit wird als die Enzymmenge festgesetzt, die 1,0 gmol p-Nitrocatecholsulfat bei pH 5,0 und 37°C innerhalb yon 30 min hydrolysiert. Die chromatographischen Arbeiten werden mit einem Gaschro- matographen (Packard, 428) durchgeftihrt. Als Detektortemperatur werden 238°C, als Ofentemperatur 140°C angegeben, und die Injektion erfolgt bei 175°C. Der Gasdurchlauf (N2) liegt bei 4 ml/min. Durch Venenpunktion werden 8 ml Blut entnommen. Ffir die Bestimmung der Gesamt-MHPG ist eine nach Vorschrift zubereitete Probe erforderlich. Zur Berechnung der MHPG-Konzentration wird ein Externalstandard yon 40 ng MHPG und 40 ng EHPG (3 Ethoxy-4-hydroxyphenylglycol) in 0,5 ml Ethylacetat verwendet. - Clin. Chim. Acta 185, 165-~76 (1989). Dept. Psych., Metro Health Med. Center and Case Western Reserve Univ., School Med., Cleveland, OH (USA) F. Knorr

High-performance liquid chromatography for cyclosporin measurement: comparison with radioimmunoassay. M. Plebani, M. Masiero, C.D. Paleari, L. Sciacovelli, D. Faggian and A. Burlina.

Ein empfind!iches, selektlves, reproduzierbares und leicht durchffihr- bares HPLC-Verfahren zur tfiglichen Routinekontrolle der Cyclosporin- konzentration in Blut wird entwickelt und mit anderen chromatographischen Verfahren und mit Radioimmunassays verglichen. Dazu wird das Verfahren von G. Sivorinowsky, S.R. Binder, M.J. Regalia und M.E. Biaggi [Ann. Clin. Biochem. 24, Suppl. 2, 64 (1987)] modifiziert. 1 mI Wasser und 2 ml des internen Standard (30% w/il3rige Acetonitril-L6- sung von Cyclosporin D) wird in 1 ml Blutprobe gegeben. Nach Zentrifu- gation bei 0°C wird der Uberstand auf eine Cyanoextraktionss/iule gegeben. fQberschiissiges Blut wird mit 15 % Acetonitril vonder S fiule gewaschen und hydrophobe Verunreinigungen mit 50% Acetonitril. Die Cy- closporine werden mit Ethanol eluiert. Das Eluat wird mit 10 .3 tool/1 Phosphorsfiure verdiinnt und mit Hexan gewaschen. Nach Zentrifuga- tion des Hexans wird das Eluat direkt auf eine Reversed-Phase C8 Mini- S~ule gegeben, die isokratisch mit gepufferter mobiler Phase (pH 6,2) (20 retool/1 Ammoniumphosphatpuffer in 56% wfigrigem Acetonitril) bei 70°C eluiert wird. Der Nachweis wird bei 210 nm im UV durchgeffihrt. Durch Vergleich der Peakverh/iltnisse kann der Cyclosporin A- Gehalt in Blut bestimmt werden. Die erhaltenen Ergebnisse stimmen gut mit solchen fiberein, die mit dem viel aufwendigeren RIA-Verfahren erhalten wurden. Die untere Nachweisgrenze (S/N =2) liegt bei 25 gg/i. Die Wiederfindungsraten liegen zwischen 104 und 98% bei Konzentra- tionen von 100 - 1000 gg/l. Die Variationskoeffizienten werden mit 2.3 - 2.7% angegeben. - J. Chromatogr. 476, 93 98 (1989). Catt. Chim. Microscop. Clin., Lab. Centr. Anal., Univ., Padova (I) R.H.S.

Quantitation of 5-fluorouracil incorporation into RNA by high-performance liquid chromatography without the use of radioactive precursors. R.C. Sawyer, R.L. Stolfi and D.S. Martin.

Die Entwicklung eines Verfahrens zur Identifizierung und quantitativen Bestimmung von 2',3'-FUMP (das 2'- und 3'-gemischte Isomere yon Fluorouridinmonophosphat) in alkalischen Hydrolysaten yon Tumor- RNA durch HPLC/UV wird beschrieben. Dazu wird den Tieren Fluo- rouracil + [3H]Fluorouracil injiziert, das Tumorgewebe entfernt, homo- genisiert, die Nucleins/iuren durch F/illung mit Ethanol abgetrennt, ge- 16st und mit 4 mol/1 NaOH hydrolysiert. Die DNA wird durch F/illung mit HC104 gewonnen und mit der Burton Diphenylamin-Farbreaktion bestimmt. In den angesfiuerten alkalischen Hydrolysaten werden die Purinnucleotide durch Erw/irmen in die Purinbasen umgewandelt. Das Hydrolysat wird neutralisiert durch Extraktion mit Tri-n-Octylamin/ Freon (1:2). Die Proben werden auf einer Resolve C~8 und 5 mmol/1 Tetrabutylammoniumhydrogensulfat (pH 2,7) chromatographiert. Das

Effluat wird im UV bei 254 nm ausgewertet. Die erhaltenen Ergebnisse sind gut vergleichbar mit solchen, die mit dem herk6mmlichen Verfahren der Messung der Sfiure-f/illbaren, Alkali-labilen Radioaktivitfit erhalten werden. - J. Chromatogr. 496, 450-455 (1989). Cancer Res. Lab., Cathol. Med. Center, Woodhaven, NY (USA) R.H.S.

Quantitation of hexadecylphosphocholine by high-performance thin layer chromatography with densitometry. I. Rustenbeck and S. Lenzen.

Ein Verfahren zur Bestimmung des antineoplastisch wirkenden Ether- Phospholipids Hexadecylphosphocholin (HDPC) wird ein dfinnschicht- chromatographisches Verfahren entwickelt. Die Lipide werden aus Pro- ben wie Homogenaten von Leberzellen, Plasma, Gesamtblut oder Ery- throcyten mit Hexan/2-Propanol extrahiert. Der Uberstand wird zur Trockne eingedampft, in Chloroform/Methanol/Wasser (30:60:8) wie- deraufgenommen und fiber eine Sephadex G15-Minis/iule entsalzt und nach erneutem Eindampfen und Wiederaufl6sen auf eine HP-TLC-Platte aufgetragen. Diese wird in Chloroform/Methanol/Triethylamin/Wasser (30:35:34: 8) chromatographiert. Nach 10 min Trocknung bei 180°C wird die Platte mit einer L6sung von 10%igem Kupfersulfat in 8 % wfil3r. Phosphors/lure gespr/iht. Die Lipide werden durch 2 min Erhitzen auf 110°C und 10 min Erhitzen auf 170°C verkohlt und dann densitometrisch bei 530 nm ausgewertet. Im Bereich von 27 pmol bis 90,55 nmol HDPC erh/ilt man eine lineare Eichkurve. Die untere Nachweisgrenze wird mit 25 pmol angegeben. Die Wiederfindungsrate liegt bei 89%. - J. Chromatogr. 525, 8 5 - 91 (1990). Inst. Pharmacol. Toxicol., Univ., G6t- tingen (D) R.H.S.

Determination of navelbine and desacetylnavelbine in biological fluids by high-performance liquid chromatography. F. Jehl, 3. Debs, C. Herlin, E. Quoix, C. Gallion and H. Monteil.

Der neue Antitumorwirkstoff Navelbin (5'-Noranhydrovinblastin) aus der Gruppe der Vincaalkaloide kann schnell, empfindlich und genau mit Hilfe eines HPLC-Verfahrens zusammen mit seinem Desacetylmeta- boliten in biologischen F1/issigkeiten bestimmt werden. Dazu werden die mit Vinblastin als internem Standard und Phosphatpuffer (pH 7) versetzten Serumproben mit Diethylether extrahiert. Der Oberstand des Zentrifugats wird eingedampft und in Methanol/HC1 (pH 2) (20:80) aufgenommen. Diese L6sung wird auf einer Cyanos/iule mit Acetonitril/ 40 mmol/1 Ammoniumacetat (55:45, pH 3) chromatographiert. Der Nachweis wird im UV bei 268 nm ausgeffihrt. Die Nachweisgrenze far S /N=4 wird mit 2,5 ng/ml ffir Navelbin in Serum und mit 5 ng/ml in Urin angegeben. Die Extraktionsausbeuten liegen um 67%. Im Bereich von 2,5-1000 ng/ml erhfilt man in Serum und yon 5-5000 ng/ml in Urin lineare Eichkurven. - J. Chromatogr. 525, 225-233 (1990). Inst. BacterioI., Hosp. Univ. Center, Strasbourg (F) R.H.S.

High-performance liquid chromatographic method for the simultaneous determinationof enrofloxacin and its primary metabolite ciprofloxacin in canine serum and prostatic tissue. K. Tyczkowska, K.M. Hedeen, D.P. Aurcoin and A.L. Aronson.

Sample preparation consisted of mixing canine serum with a 1:1 dilution of acetonitrile and 0.1 M sodium hydroxide followed by ultrafiltration through a 10000 molecular mass cut-off-filter. Prostatic tissue was sonicated with the same solution prior to ultrafiltration. Separation of these two quinolones in the ultrafiltrate was accomplished by ion-paired LC using a reversed-phase analytical column eluted with an acetonitrile-methanol-water solution. Enrofloxacin and ciprofloxacin were detected by a photometric ultraviolet-visible detector set at 278.6 nm and confirmed by a photodiode array detector operating from 230 to 360 nm. The limits of detection for enrofloxacin and ciprofloxacin were 4 and 2 ng/mI, respectively. -- J. Chromatogr. 493, 337 - 346 (1989). Clin. Pharmacol. Unit, College Veterin. Med., State Univ., Raleigh, NC (USA)

Determination of metabolites of etophyllinclofibrate in plasma by reversed- phase high-performance liquid chromatography. V. Ostrovskfi, A. Pechovfi and X. Svobodfi.

Die Verbindung ist ein aktives Agens gegen Hyperlipfimie und wird im K6rper in seine Komponenten Clofibrins/iure und Etophyllin zerlegt. Bei den bisher bekannten Nachweismethoden waren stets zwei Extrak- tions- und Trennschritte erforderlich. Kennzeichen der neuen Methode


ist, dab nur noch ein Schritt n6tig ist. Ausjhhrung. 1 ml Plasma wird mit 200 gl Internstandard (Ornidazol, 14 gg/ml) und 200 gl 1M HC1 gemischt und dreimal mit Chloroform extrahiert; der Extrakt wird eingedampft und in 1 ml mobiler Phase ohne Natriumheptasulfonat gel6st. Davon werden 100 gl auf die S/iule mit Spherisorb ODS-1 (Spectra Physics, Darmstadt) 25 cm x 4 mm gegeben. Die mobile Phase wird gemischt aus 8 Tln Acetonitril mit 92 Tln 0.005 M Natriumheptasulfonat in Wasser. Natriumheptasulfonat reduziert die Retentionszeit yon Clofibrins~iure. Die Wiederfindungsrate yon zugesetzten Komponenten wird mit 64% ffir Clofibrins/iure und 77% ffir Etophyllin angegeben. - J. Liquid Chromatogr. 12, 2793- 2799 (1989). Dept. Physical Anal. Chem., Drug Res. Inst., Modra (CS) A. Niemann

Simultaneous determination of pyrimethamine and mefloquine in human plasma by high-performance liquid chromatography with ultraviolet detection. A. Guenzi, G. Cappelletti, A. Scala and M. Zanetti.

A rapid, sensitive and selective method was developed for the simultaneous determination of pyrimethamine and mefloquine, two of the active ingredients of Fansimef, in human plasma. The procedure involved extraction of the compounds and the internal standard nitrazepam from basified plasma with dichloromethane and chromatography on a Cls column 0,tBondapak, 300xY9 mm I.D.) with acetonitrile/phosphate buffer as the mobile phase and UV detection at 222 nm. The limit of quantification was 10 ng/ml for both substances, using a 1-ml plasma specimen. The mean inter-assay precision was 2.8% for pyrimethamine and 4.7% for mefloquine up to 800 ng/ml. The practicability of the method was demonstrated by the analysis of more than 1200 plasma samples from several pharmacokinetic studies involving single-dose administration of Fansimef to both patients and volunteers. - J. Chromatogr. 494, 219-230 (1989). Pharmacokinetics Lab. Prodotti Roche SpA, Milan (I)

Determination of quinonoid dihydrobiopterin by high-performance liquid chromatography and electrochemical detection. S. Heales and K. Hyland.

Sodium bisulfite is shown to react with quinonoid dihydrobiopterin to form a stable adduct. Sodium bisulfite does not react with tetrahydrobiopterin. Quinonoid dihydrobiopterin reacts with dithioerythritol to form tetrahyrobiopterin, whereas the quinonoid dihydrobiopterin bisulfite adduct does not. Using these properties we have developed an indirect method for the quantitative measurement of quinonoid dihydrobiopterin. The method requires division of a sample into two. Dithioerythritol is added to one half (a). This converts quinonoid dihydrobiopterin to tetrahydrobiopterin and prevents the oxidation of tetrahydrobiopterin. Measurement of the tetrahydrobiopterin content of this sample by electrochemistry following HPLC separation (with dithioerythritol present in the mobile phase to prevent autoxidation of the tetrahydrobiopterin on column), therefore provides a total value of the tetrahydrobiopterin plus quinonoid dihydrobiopterin present within the original sample. Sodium bisulfite is added to the other portion of the sample (b), followed immediately by dithioerythritol which prevents autoxidation of the remaining tetrahydrobiopterin. The bisulfite reacts with the quinonoid dihydrobiopterin present and the quinonoid dihydrobiopterin-bisulfite adduct is no longer detected by electrochemistry at the retention time of tetrahyd~obiopterin. - J. Chromatogr. 494, 7 7 - 8 5 (1989). Dept. Child Health, Inst. Child Health, London (GB)

Simultaneous determinations of tolbutamide and its hydroxy and carboxy metabolites in serum and urine: Application to pharmacokinetic studies of tolbutamide in the rat. S. St-Hilaire and P.M. Belanger.

Methods of analysis of tolbutamide (1) and its hydroxylated (2) and carboxylated (3) metabolites in serum and urine based on HPLC were developed. The separation was performed on a Apex ODS column in the isocratic mode using a mobile phase composed of 22.5% acetonitrile, 77.5% Sorensen phosphate buffer (pH 7.0), and 0.30 ml of tetrabutylammonium phosphate reagent (Pic A). The compounds were detected at 254 nm. The retention times of 3, 2, 1, and the internal standard chlorpropamide were 3.1, 4.1, 14.8, and 10.0 rain, respectively. These conditions were suitable for the simultaneous quantitation of 1, 2, and 3 in serum or plasma samples, but not for the determination of metabolites 2 and 3 in urine. For the analysis of 2 and 3 in urine, the mobile

phase was modified to 18% acetonitrile, 82% Sorensen phosphate buffer (pH 7.0), and 0.35 ml of Pic A. Under these conditions, the retention times of the carboxy and hydroxylated metabolites and the internal standard salicylic acid were 4.6, 6.7, and 8.1 min, respectively. These methods were applied to study the pharmacokinetics of I administerd intravenously and intraperitoneally to the rat. Tolbutamide was almost completely recovered as metabolites 2 and 3 in the urine within 24 h. - J. Pharm. Sci. 78, 863 - 866 (1989). Ecole Pharm., Univ. Laval, Ste-Fox, Qu6bec (CDN)

Assay for methylnaltrexone in rat brain regions and serum by high-performance liquid chromatography wtih coulometric electrochemical detection. C. Kim, R. Cheng, W.A. Corrigall and K.M. Coen.

A simple and sensitive method is described for the determination of methylnaltrexone, a quaternary narcotic antagonist. Perchloric acid extracts of the brain tissue or serum were passed through a normal- phase solid-phase extraction CN column, and then analyzed by RP- HPLC on Ultrasphere ODS C18. Methylnaltrexone gave a linear response over the range of 12.5-100 ng in 1.0 ml for cerebellar homogenates and 25-200 ng in 50 ~L1 for serum. The average between- assay coefficients of variation for methylnaltrexone from 1.0 ml of cerebellar homogenate and 50 ~1 of serum were 5.2 and 3.6%, respectively, over the concentration range studied. The within-assay coefficients of variation at 12.5 ng/ml cerebellar homogenate and 25 ng/50 gl for serum were 7.4 and 4.6%, respectively. Analytical recovery ofmethylnatrexone, added to cerebellar homogenate and serum samples, were 85 and 89%, respectively. - Chromatographia 28, 359-363 (1989). Addict. Res. Found., Toronto, Ont. (CDN)

Determination of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine by CGC. D. Mancas, M. Leanca and Ch. Chiriac.

Der zum Nachweis yon Kohlenstoffdisulfid bei belasteten Personen gebr/iuchliche Jod-Azid-Test (ITA) (D. Djuric, N. Surducki und I. Ber- kes; Br. J. Ind. Med. 22, 321 (1965)) ist ffir sehr geringe Mengen an CS2 nicht ausreichend empfindlich. Seitdem TTCA als Metabolit yon CSz identifiziert ist, k6nnen auch geringste Mengen CS2 fiber einen biologischen Weg chemisch nachgewiesen werden. Die Autoren zeigen, dab hierffir die Capillar-GC der HPLC fiberlegen ist. Ausffihrung. Eine Urin- probe yon 5 ml wird mit 1,5 g Kochsalz versetzt und mit 5N HC1 auf pH I eingestellt. Die Probe wird zweimal mit 10 ml Ethylacetat auf dem Vortex extrahiert, zentrifugiert und der Extrakt zunfichst auf 1 ml, dann in einer Mikroschale unter Stickstoff zur Trockne eingeengt. Ffir die HPLC wird in 200 gl Methanol gel6st und fiber eine Chromsil 6 gm C18-Sfiule in einem Liquochrom 2010 HPLC Instrument (Labor Mim Budapest) mit UV-Detektor (273 nm) chromatographiert. Zur GC wird in 100 ~tl Methanol gel6st, mit einem Uberschul3 Diazomethan/Dime- thylether bei 0°C fiber 1 h verestert, eingedampft und zur GC in Isooctan ge16st. Die Chromatographie wurde in einer 25 m x 0,32 mm Quarzs~iule, imprfigniert mit immobilisiertem PS-225 (Mega, Italien), verbunden mit einem Thermoionen-Detektor, am Fraktovap 2350 AC (Carlo Erba, Mailand) ausgeffihrt: Sfiulentemperatur 2 min 68°C auf 1 J 6 °C mit 20°/ rain, nach 1 rain mit 0,1 °/rain bis zum Austritt des TTCA-Methylesters. Die abgedruckten Chromatogramme lassen die besere Trennung dutch Capillar-GC erkennen. - J. High Resolut. Chromatogr. 12, 828-829 (1989). Inst. Hyg., Jassi (R) A. Niemann

Determination of nicotine metabolites by HPLC after complexation with diethylthiobarbituric acid. C.L. Smith, S. O'Doherty, M. Cooke and D.J. Roberts.

Zur Bestimmung von Nicotinmetaboliten in Urin werden die Proben mit Acetatpuffer (pH 4,7), KCN, Chloramin T und Diethylthiobarbitur- s/lure versetzt. Das Reaktionsgemisch wird nach 20 rain fiber eine C~8 Sep-Pak Kartusche gegeben, vonder die Diethylthiobarbitursfiurekom- plexe mit Methanol extrahiert werden. Die gef/irbten Methanolextrakte werden auf einer LiChrom C ls ROSii-S/iule mit einem Gradienten aus 35 70% Methanolin Wasser + Natriummethansulfonat als Ionenpaa- rungsreagens getrennt. Der Nachweis der Komplexe kann bei 530 nm durchgeffihrt werden. Mit dem Verfahren k6nnen Cotinin, Coffein und 3'-Hydroxycotinin getrennt werden. Es wird mit internen Standards gearbeitet. - Anal. Proc. 26, 348-351 (1989). Dept. Inorgan. Chem., Cantock's Close, Bristol (GB) R.H.S.

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