2.8 Pharmaceuticals and cosmetics 409

of the first and second peaks were linearly related to the total concen- tration of inosine and hypoxanthine in the range 0.01~2 mM and to the total concentration of inosine-Y-monophosphate, inosine and hypoxanthine in tile range 0.01 ~1 mM. The detection limits were 0.5 x 10 6 M for the first peak and 2 x 10 6 M for the second peak when a 10-1al sample was injected. The proposed FIA system was found to be useful as a new, simple, rapid and selective method for the estimation of fish freshness. - Bunseki Kagaku 37, 236-241 (1988) (Japanisch, mit engl. Zus.fass.). Dept. Appl. Chem., Coll. Engin., Univ. Osaka Prefect., Osaka (J)

Determination of inorganic tin in biological samples by hydride generation- atomic absorption spectrometry after silica gel cleanup. T. Tsuda, M. Wada, S. Aoki and Y. Matsui.

A method is described for the determination of inorganic tin in biologi- cal samples by hydride generation-atomic absorption spectrometry (HG- AAS). A sample is extracted with ethyl acetate after addition of HC1 and NaC1. The concentrated extract is passed through a silica gel column. The column is washed with ethanol, water, and 0.2 N HC1 successively, and then inorganic tin is eluted with 2 N HC1 and measured by HG- AAS. Recoveries from fish muscle spiked with 0.1 gg/g Sn 4+ are 78.9 _+ 4.2% (average + standard deviation, n = 5). The detection limit is 0.01 gg/g as Sn. - J. Assoc. Off. Anal. Chem. 71, 373-374 (1988). Shiga Prefect. Inst. Publ. Health Environ. Sci., Ohtsu, Shiga (J)

Identification of Escherichia coli from shellfish and related environments by automicrobic system. J.L. Tardi6, K. O'Brien and T. Latt.

A total of 463 fecal coliform positive isolates obtained from shellfish and related samples gave typical Escherichia coli IMViC reactions. E. coli identifications for 458 (99%) of these isolates were confirmed using a combination of the Automicrobic System (AMS) and the API 20E system (reference system). The AMS (test system) identified 433 isolates as E. coli," the remaining 25 (5%) isolates were identified as E. hermanii by the test system and as E. coli by the reference system. Additional tests performed on the isolates identified as E. hermanii confirmed those AMS identifications to be incorrect. - J. Assoc. Off. Anal. Chem. 71, 582 - 584 (1988). Food Drug Admin., Baltimore Distr. Lab., Baltimore, MD (USA)

Comparison of APHA and elevated temperature enrichment methods for recovery of vibrio cholerae from oysters: Collaborative study. A. DePaola, M.L. Motes and R.M. McPhearson.

Two methods (the American Public Health Association (APHA) method and the elevated temperature method) for recovery of Vibrio cholerae from oysters were compared in a collaborative study. Oysters were inoculated with high (about 150 cells/g) and low (about 20 cells/g) levels of V. cholerae. The elevated temperature method gave a signifi- cantly higher (P < 0.05) recovery rate and showed greater specificity (P < 0.01), as determined by the confirmation rate of suspect colonies. The elevated temperature method required only 25% of the labor and materials necessary for the APHA method. The elevated temperature method has been adopted official first action. - J. Assoc. Off. Anal. Chem. 71, 584-589 (1988). Food Drug Admin., Fish. Res. Branch, Dauphin Island, AL (USA)

2.8 Pharmaceuticals and cosmetics

Totally automated robotic system for liquid chromatographic analysis of solid dosage formulations with the aid of a reduced Kalman filter. R. Matsuda, Y. Hayashi, M. Ishibashi and Y. Takeda.

An automated system for the analysis of solid dosage formulations is described, comprised of a commercially available robotic system, an high-performance liquid chromatograph and microcomputers. By means of the robotic system, several sample solutions are simultaneously pre-

pared from the solid formulations and then injected successively into the chromatograph at regular, excessively short intervals. The overlapped peaks in the resulting complex chromatogram are resolved and quantitat- ively analyzed by a reduced Kalman filter. A content uniformity test was performed for twenty commercial diazepam tablets; the total analysis time involving the tablet disintegration and chromatographic determi- nation was significantly reduced. - J. Chromatogr. 438, 319-327 (1988). Div. Drugs, Nat, Inst. Hyg. Sci., Setagaya-ku, Tokyo (J)

Polar contributions of the stationary phase to the reversed-phase ion- pair high-performance liquid chromatographic separation of quaternary ammonium drugs. J.A. De Schutter and P. De Moerloose.

The chromatographic reproducibility of a methodology, developed for the separation and determination of quaternary ammonium drugs by reversed-phase ion-pair column liquid chromatography, was studied. The results in terms of retention dependence on the residual silanol content of the octadecyl stationary phase and column aging were com- pared with those obtained with conventional separation techniques. By on-column silylation with N-trimethylsilylimidazole, it was demon- strated that eluents containing both amines and alkanesulfonates, beside a higher resolving power, provide reproducible separations which are far less dependent on the residual and generated silanol groups compared to those obtained with eluents containing only an organic amine. - J. Chromatogr. 437, 8 3 - 9 5 (1988). Dept. Pharm. Chem., Drug Quality Control, State Univ., Ghent (B)

Ion-pair reversed-phase thin-layer chromatography of basic drugs using sufonic acids. R.J. Ruane and I,D. Wilson.

Eine Reihe basischer pharmazeutischer Wirkstoffe (Testgemisch) k6n- nen gut d/innschichtchromatographisch unter Verwendung yon Sulfon- s[iure-Ionenpaar Agentien getrennt werden. Dabei werden Trennungen sowohl auf C18-gebundenen Silicagel-, mit Paraffin beschichteten Silica- gel- und Silicagelschichten durchgef/ihrt. Als FlieBmittel werden Wasser/ Methanol-Gemische eingesetzt. Die ionenpaarbildenden Reagentien hatten nur auf den C18-gebundenen Silicagelen einen EinfluB auf die Trennung nnd nur, wenn die Reagentien bereits in die station[ire Phase eingebettet wurden. Die st/irksten Reduktionen in den Rf-Werten der Testverbindungen erhielt man bei Beschichtung der Platten mit Natri- umdodecylsulfat. - J. Chromatogr. 441, 3 5 5 - 3 5 0 (1988). Dept. Safety Med., ICI Pharm. Div., Alderley Park, Macclesfield, Cheshire (GB)

R.H.S.

Spectrophotometric determination of cetylpyridinium chloride in drugs by ion pair extraction with quinidine and Bromocresol Green. T. Sakai, Y. Ohsugi, T. Kamoto, N. Ohno and H. Sasaki.

Although cetylpyridinium cation does not form an ion associate with divalent Bromocresoi Green (BCG 2-) at ca. pH 7, the extractability of cetylpyridinium is enhanced only in the presence of quinidine. The proposed extraction system is based on the reaction of monovalent quinidine cation (HQuinidine+), BCG 2 - and cetylpyridinium cation to form a 1:1:1 ternary ion associate (HQuinidine+-BCG2--cetylpyridi - nium +) extractable into 1,2-dichloroethane, moderate polar solvent. Maximum absorption wavelength of quinidine-BCG associate was at 550 nm, but the wavelength of ternary ion associate shifted to 633 nm and bathochromic effect was also observed. The lincarity of the calibration curve was improved and the molar absorptivity increased compared with cetylpyridinium-BCG extraction system. Moreover, as the optimum pH was at 8.9~9.6, amines such as chlorpheniramine, dibucaine and diphenhydramine did not interfere with the absorption measurement. MoIar absorptivity was 35800 mol- i cm- 11 fiir quinidine- BCG-cetylpyridinium associate at 633 nm and relative standard devi- ation, 1.8%. The proposed method could be applied to the spectrophotometric determination of cetylpyridinium chloride in multi- component drugs. - Bunseki Kagaku 37, 174-179 (1988) (Japanisch, mit engl. Zus.fass.). Dept. Chem., School Liberal Arts, Asahi Univ., Hozumi, Motosu-gun, Gifu (J)

Spectrophotometric determination of glucose and fructose in injections using tetracyanoethylene reagent. S. Belal, A.A. E1 Kheir, M. Ayad and S,. E1 Adl.

410 2 Particular products and fields of application

Glucose und Fructose werden spektrophotometrisch nach Reaktion ihrer Osazone mit Tetracyanoethylen (TCNE) bestimmt. -- Arbeits- weise. Die Mischung der w/igrigen L6sung des Monosaccharids (5 rag) und 5 ml 5% Phenylhydrazin-HC1 (in Wasser) wird 10 rain bei 100 - 110~ g gehalten und nach Abkiihlung mit Ethylacetat extrahiert; das Volumen des Extrakts wird auf 50 ml gebracht. Zu 5 ml des Extrakts werden 2 ml 10 -3 M TCNE (in CHC13) zugeffigt. Nach 5 rain wird die optische Dichte bei 455 nm gegen eine Blindlfsung gemessen, und an Hand einer Eichkurve ausgewertet. Die Beersche Regel gilt ffir 0.001 - 0.01 mg/ml Monosaccharid. Die Zurfickgewinnung von Glucose betrug 99.87 +_ 0.30% und die yon Fructose 99.80 + 0.26%. Die vorgeschla- gene Methode ist empfindlicher und genauer als die mittels Phosphomo- lybdat. - Microchem.. J. 37, 2 5 - 2 9 (1988). Dept. Pharm. Chem., Fac. Pharm., Univ., Zagazig (ET) J. Eliassaf

Determination of procaine hydrochloride by pyrolysis GC. Y. Minami, T. Mitsui and Y. Fujimura.

The determination of procaine hydrochloric was studied by means of curie point pyrolysis GC using an induction heating pyrolyser. The procedure for the determination was as follows: Procaine hydrochloride in water (1~50 gg) was applied onto 30 mg of mixed powder [Ni : KI : (NH4)2SO4 = J0: 3 : 2] placed on pyrofoil by use of a microlitre syringe. After heating on a hot plate for 5 rain at 100~ to evaporate water the pyrofoil was pyrolysed for a 4 s at 590~ The procaine hydrochloride reacts with potassium iodide and ammonium sulfate to form ethyl iodide. The peak area of ethyl iodide was used for the determi- nation of procaine hydroehloride. No detectable interference was ob- served in determination of procaine hydrochloride by such compounds that sodium chloride, starch, glucose, lactose, fresh blood and putrid blood. The calibration curve for procaine hydrochloride constructed by using the peak area method were linear over the concentration range of 1 ~50 gg. The relative standard deviation (n = 10) was 1.95 for 24.5 Ixg of procaine hydrochloride. -- Bunseki Kagaku 37, 259-262 (1988) (Japanisch, mit engl. Zus.fass.). Forensic Sci. Lab., Prefect. Police Osaka (J)

Gravimetric determination of glafenine in tablets and suppositories. S.A. Ismaiel and E.A. E1-Moety.

Von feingepulverten Glafenin(G)-Tabtetten wird eine, etwa 0,5 g G entsprechende Menge in einen 100 ml-Megkolben gewogen, in etwa 80 ml 0,1 M HC1 gel6st, mit 0,1 M HC1 auf 100 ml erg/inzt und durch ein trockenes Whatman No. 1 filtriert. Ein 0,5 g G enthaltendes Supposi- torium wird mit 10 ml CHC13 und genau 100 ml 0,1 M HC1 bis zum Schmelzen des Zfipfchens erw/irmt, 5 rain lang intensiv geriihrt und zum Abkiihlen stehen gelassen. Die saure, G enthaltende Phase wird filtriert. Je 10 ml der G-haltigen Ausziige werden nach Zusatz yon 1 ml HC1 und 10ml 1:10 verdfinnter Essigs/iure (E) langsam mit 6 ml 0,25 m Kaliumwismutiodid-L6sung versetzt, gerfihrt, nach 30 min langem Ste- hen nochmals aufgeriihrt und nach weiteren 10 min durch ein G4-Glas- filter gesaugt. Nach Waschen mit 5,5 und 10 ml E und 2mal 5 ml H20 wird der Filterinhalt 6 0 - 9 0 rain bei 105~ getrocknet. 1 g der Ffillung entspricht 0,3738 g G. - Zent.bl. Pharm. Pharmakother. Lab.diagn. 127, 5 7 - 5 9 (1988). Res. Gen. Direct., Misr Co. Pharm. Ind., Post EI- Zeitoun, Cairo (ET) K. S611ner

Spectrophotometric determination of indomethacin. C.S.P. Sastry and A.R.M. Rao.

Zwei spektrophotometrische Bestimmungsmethodeu ffir Indometha- cin (I) [l-(4-Chlorbenzoyl)-5-methoxy-2-methylindol-3-yl-essigs/iure] werden vorgeschlagen. - Methode A: Eine Probe mit 10-100 Ixg I wird mit 1 ml 2 M HC1, 3ml 3-Methyl-2-benzothiazotinonhydrazon- hydrochlorid (0.2% in Wasser) und 1 ml 0,8% w/igrige FeC13-L6sung versetzt und nach 5 rain mit Wasser auf ein Gesamtvolumen von 10 ml gebracht. Die optische Dichte wird nach 15 min bei 660 nm gegen eine Blindl6sung gemessen und die Menge an I durch eine Eichkurve ermit- telt. - Methode B: Eine Probe mit 20--160 gg I u n d 5 ml 6% SbCI3 (in HC1) werden 7 min bei 75~ gehalten, abgekfihlt und mit konz. HCI auf 10 ml gebracht. Nach 2 rain wird die optische Dichte gegen eine Blindl6sung bei 600 nm gemessen und an Hand einer Eichkurve ausge- wertet. Die Zurfickgewinnung yon I betrugt 98.9 - 99.5% und die Fehler- grenze + 1.68% (Methode A) bzw. 1.23 (Methode B). - Analusis 15,

569 - 570 (1987). Dept. Foods, Drugs and Water, School Chem., Andhra Univ., Walta~ir (IND) J. Eliassaf

Proton magnetic resonance spectroscopic method for determination of phenylbutazone and oxyphenbutazone in tablets. S. Husain, M.K. Tullah and R,N. Rao.

A simple, specific, and rapid 1H-NMR spectroscopic method for the assay of phenylbutazone and oxyphenbutazone is described. Spectra are recorded in CDC13 containing 1,3-dichloro-5-nitrobenzenes as an internal standard. The aromatic proton resonances for the standard, at ~7.7 and 8.2, are well separated from those of phenylbutazone and oxyphenbutazone, which are in the region of ~6.5-7.3 ppm. Average percent recoveries of phenylbutazone and oxyphenbutazone were 98.9 and 98.6 with standard deviations of 0.6 and 0.7, respectively. Commer- cial formulations were analyzed and the results obtained by the proposed method closely agreed with those found by the British Pharmacopoeia method. - J. Assoc. Off. Anal. Chem. 71, 525-527 (1988). Reg. Res. Lab., Anal. Div., Hyderabad (IND)

Bromimetric determination of some benzothiadiazine diuretics in dosage forms. F. Beial, F. Ibrahim and A. E1-Brashy.

A simple titrimetric method was developed for the determination of some benzothiadiazine diuretics in dosage forms, involving the use of 1,3-dibromo-5,5-dimethylhydantoin of N-bromosuccinimide as the ti- trant. A known excess volume of either reagent is added and, after a specified time, the residual reagent is determined iodimetrically. The stoichiometry of the reaction was assessed and a proposal for the reaction pathway is presented. The reaction products were isolated and identified by NMR and IR spectroscopy. The results were compared statistically with those obtained using N-bromosuccinimide and official methods, and were found to be in good agreement. - Analyst 113, 637-639 (1988). Dept. Anal. Chem., Fac. Pharm., Univ., Mansoura (ET)

Reduetive amperometric determination of nitrofurantoin and acetazol- amide at a sessile mercury drop electrode using flow injection analysis. A.G. Fogg and A.B. Ghawji.

The application of a laboratory-built sessile mercury drop detector in drug analysis has been illustrated by the flow injection amperometric determination of nitrofurantoin and acetazolamide. Nitrofurantoin was determined in the range 1 - 5 0 gg mt -1 at -0 .70 V vs. SCE in a carrier stream consisting ofpH 7.5 Britton-Robinson buffer containing sulphite to lower the background oxygen level; acetazolamide was determined in the range 1 0 - 7 0 gg m1-1 at -0 .85 V vs. SCE in 0.1 M hydrochloric acid. The procedures were applied with good accuracy and precision to the determination of the drugs in tablet formulations. - Analyst 113, 727-730 (1988). Chem. Dept., Univ. Technol., Loughborough, Leices- tershire (GB)

Fast Black K salt: A visualisation reagent for thin-layer chromatography of beta-adrenergic blocking drugs. I. Ojanperfi and A. Ruohonen.

Eine empfindliche Methode zur Sichtbarmachung yon Beta-Blocker- Substanzen auf entwickelten Diinnschicht-Platten benutzt Echt-Schwarz K-Salz als Reagens. Fiir elf Substanzen der Propranolol-Klasse werden die Rf-Werte und die Nachweisgrenzen aufgelistet. Arbeitsweise: 1 gl der methanolischen L6sung mit 0,05 bis 1,0 mg/ml Wirkstoff wird auf eine beschichtete HPTLC-Platte aufgebracht und mit Ethylacetat/Methanol/ Ammoniak (85 : 10: 5) entwickelt. Die Platte wird danach mit 0,5% w~il3- riger Farbstoffi6sung mit 0,5 M NaOH und nochmals mit Farbstoffl6- sung besprfiht. - Andere kardiovaskul/ire Wirkstoffe st6ren praktisch nicht. Die Nachweisgrenze fiir Wirkstoffe in reiner Form bzw. in Urin- Proben betr~igt 0 ,1 -10 gg/ml. Die F/irbung wird durch die Reaktion des Diazoniumsalzes mit der sekund/iren Amingruppe der Wirkstoffe erhalten. - J. Anal. Toxicol. 12, 108-110 (1988). Dept. Forensic Med., Univ., Helsinki (SF) B.R. Glutz

Application of p-aminophenol in the estimation of isoxsuprine hydro- chloride and its dosage forms. D.M. Shingbal and A.S. Khandeparkar.

Isoxsuprine HC1 [benzenemethanol 4-hydroxy<~(l-(chloromethyl-2- phenoxyethyl)aminoethyl HC1] reacts with a p-aminophenol to form a coloured species suitable for colorimetric determination of the drug. The species shows )~max at 635 nm and obeys Beer's law from 10-110 ppm.

2.8 Pharmaceuticals and cosmetics 411

The method is applied to determine the drug in formulations (tablets, injections) without interference from excipients and diluents (recovery 100.6-102.3%). - Procedure. To a suitable aliquot of the drug soln. add 0.5 ml of 0.05% NaOH and 0.2 ml of 0.1% p-aminophenol and allow to stand for 35 rain. Dil. to 10 ml. Measure the absorbance at 635 nm against a reagent blank. - Indian Drugs 25, 255-256 (1988). Goa College Pharm., Pan@, Goa (IND) M. Katyal

Determination of prifinium bromide in six pharmaceutical formulations by reverse-phase HPLC. S.I. Sa'sa, I.M. Jalal and H.S. Khalil.

Prifinium bromide is an anti-cholinergic drug, available commercially in various pharmaceutical formulations such as tablets, suppositories, syrups, and ampoules. The present available analytical methods are time-consuming and range from non-aqueous titration to UV- spectrophotometry to ion-pair visible spectrophotometry. The method reported here is a fast, reliable, and stability-indicating reversed phase HPLC. The mobile phase was 0.03 M ammonium acetate in acetonitrite/ water (65:35); the pH was adjusted to 4.0 with glacial acetic acid. The column utilized was (250 mm x 4.6 mm i.d.) Supelcosil LC-8-DB (5g) and detection was carried at 254 am. Benzophenone was used as internal standard. The assay was applied to commercial products and the results expressed in (% label claim + RSD) are (99.58 + 0.36), (100.50 _+ 0.40), (99.95 _+_+ 0.70), (99.94 + 0.29), (100.28 + 0.52), and (99.99 +_ 0.57) for six commercial formulations. The method was tested for linearity, recovery, and specificity and was found fast, stability-indicating, and free from interferences. - J. Liquid Chromatogr. 11, 447-462 (1988). Yarmouk Univ., Chem. Dept., Irbid (JOR)

High performance fiquid chromatographic determination of levodopa from pharmaceutical preparations. S,S. Zarapker, R.V. Rele, V.J. Doshi and V.M. Shah.

High performance liquid chromatography is used for determination of ievodopa (3-hydroxy-L-tyrosine) from pharmaceutical preparations without interference from excipients (recovery 99.2%). The assay is carried out using Resolve Tm, 5 g spherical C 18 column. Catachin soln. is used as internal standard. The mobile phase consists of methanol/ water/acetic acid (50:50:1). The elution is performed at a flow rate of 0.5 ml/min and the detection is done at 281 am. A plot of area ratios vs levodopa concentration is linear in the range 0.5-30.0 ppm. - Indian Drugs 25, 245-247 (1988). Dept. Chem., D.G. Ruparel College, Bombay (IND) M. Katyal

Quantitation of terfenadine pseudoephedrine hydrochloride, and isuprofen in a liquid animal dosing formulation using high-performance liquid chro- matography. R.C. George and J.J. Contario.

Stability-indicating assay methods based on HPLC have been de- veloped for the quantitation of terfenadine, pseudoephedrine hydro- chloride, and ibuprofen when combined in an aqueous 0.5% w/v Tween 20 and 0.5 % methylcellulose animal dosing formulation. Because of the diversity of this drug mixture two separate chromatographic systems were required for the assays. A reversed phase system using a 3 gm Spherisorb ODS-2 column was used to assay for terfenadine and ibuprofen. An ion-exchange system using a 10-gm Partisil SCX column was used to assay for pseudoephedrine hydrochloride. The methods are accurate and precise with relative standard deviations over the concen- tration ranges of interest of 2% or less. - J. Liquid Chromatogr. 11, 475-488 (1988). Mcrrell Dow Res. Inst., Cincinnati, OH (USA)

Thin-layer chromatographic separation of some sulfa drugs using aceto- acetanilide as a coupling agent. R. Jain and A. Bhatia.

Einige Sulfawirkstoffe k6nnen direkt auf Silicageldfinnschichten in ihre Acetoacetanilid-Derivate umgewandelt und dann getrennt werden. Gute Ergebnisse werden erhalten, wenn die mit Natriumnitrit hergesteli- ten Diazoniumsalze der Sulfawirkstoffe auf mit 1% Tetrabutylammoni- umbromid imprfignierte Silicagel-D/innschichten aufgetragen werden. Die Auftragsstellen sind vorher mit Acetoacetanilid befeuchtet worden. Die in situ Bildung der Derivate erfolgt auf der Dtinnschichtplatte und die Derivate werden gut in Dichlormethan/CCl4/Methanol (45:50:5) getrennt. Alle 12 Kopplungsprodukte der nntersuchten Sulfawirkstoffe, die parallel mit authentischen Verbindungen laufen, k6nnen mit diesem System getrennt werden. Da die Derivate durch ihre Eigenffirbung als

gelbe Flecken beobachtet werden k6nnen, ben6tigt man kein Spr/ih- reagens. - J. Chromatogr. 441, 454-457 (1988). Schoool Studies Chem., Jiwaji Univ., Gwalior (IND) R.H.S.

Bestimmung von Sulfonamiden in Tierarzneimitteln mit HPTLC. U. de La Bigne.

Zur Bestimmung yon Sulfonamiden in Ffitterungsarzneimitteln fiir Tiere wird eine HPTLC-Methode entwickelt. Dazu werden die Proben mit Aceton extrahiert, filtriert, dem Filtrat n-Hexan zugegeben und gesch/ittelt. Die untere Phase wird eingeengt, der Riickstand in Aceton aufgenommen und aufeiner Kieselgel 60 F 254 HPTLC-Platte aufgetra- gen. Dann wird eine automatische Mehrfachentwicklung mit Universal- gradient auf Dichlormethan-Basis (20 Stufen) durchgeffihrt. Die quanti- tative Auswertung erfolgt mit einem CAMAG TLC SCANNER IImi t Rechnersteuerung mit Mel3wellenlfingen bei 265 und 366 am. Mit dem Verfahren kann eine absolute Nachweisgrenze von 10 ng erreicht wer- den, groge Probenmengen k6nnen neben Standardl~roben bestimmt wet- den. Das ohne Derivatisierungsschritt arbeitende Verfahren identifiziert die Verbindungen leicht durch die computerunterstfitzte Spektren- und Mehrwellenl/inge-Korrelation. LP-Special 88, 6 0 - 64 (1988). CAMAG, CH-4132 Muttenz (CH) R.H.S.

Quantitative and qualitative analysis of saframyeins. Polarographie and voltammetric behavionr and direct polarographic determination of safra- mycin A in fermentation broth and the high-performance liquid chromato- graphic determination of various saframycins. P.M. Bersier, H.-B. Jenny.

The polarographic and voltammetric behaviour of various safra- mycins has been studied. The scope and limitations of their individual and simultaneous determination and the direct determination of saframycin A in fermentation broth, as compared with results obtained using an HPLC method which allows separation of complex mixtures, are discussed. - Analyst 113, 721-726 (1988). ElectroanaI. Polaro- graphic Lab., Ciba-Geigy, Basle (CH)

Flow injection analysis as a diagnostic tool for development and testing of a penicillin sensor. T.D. Yerian, G.D. Christian and J. Ruzicka.

A penicillin sensor is developed for continuous, on-line analysis. The sensor consists of the enzyme, penicillinase, cross-linked with ;bovine serum albumin into a cellulose pad or covalently attached to th~ cellu- lose, with an acid-base indicator dye also covalently immobilized to the surface of the cellulose. The sensor is placed within a flow injection optosensing system to monitor changes in pH and is subjected to a thorough evaluation, using the flow injection analysis technique : sensor stability (both dye and enzyme stability), speed of sensor response, sensor sensitivity, and sensor lifetime data are obtained. - Anal. Chem. 60, 1250-1256 (1988). Cent. Proc. Anal. Chem., Dept. Chem., Univ., Seattle, WA (USA)

Spectrophotometric microdetermination of amoxicillin and neomycin with chloranil. T.S. A1-Ghabsha, T.N. A1-Sabha and G.A. Al-Iraqi.

Amoxicillin-Trihydrat (25 - 625 gg) und Neomycinsulfat (10 - 250 gg) werden spcktrophotometrisch mit Chloranil als 7c-Akzeptor bestimmt. Die Farbreaktion erfolgt sofort in Boratpuffer pH 9 und wird durch Stehen im 45~ Wasserbad fiir 1,4 h bzw. 1,1 h stabilisiert. Die Absorp- tion wird in 1 cm-Kiivetten bei 347 nm gemessen. Die Zuriickgewinnung betrug 100 + 1.0% und die Standardabweichung ~< 1.9%. - Microchem. J. 36, 323-325 (1987). Dept. Chem. Coll. Education, Univ. Mosul (IRQ) J. Eliassaf

Liquid chromatographic determination of medroxyprogesterone acetate in tablets. A.A. Fatmi, G.V. Williams and E.A. Hickson.

A reverse-phase octadecylsilane (C18) column with a mobile phase of methanol/0.01 M dibasic ammonium phosphate (80:20) v/v, pH 7.2 _+ 0.1) and photometric detection at 254 nm separates medroxypro- gesterone acetate from excipients. Detector responses were linear to concentrations of medroxyprogesterone acetate over the range 5 0 - 150 gg/ml (r = 0.999). Mean recovery of medroxyprogesterone acetate added to tablet excipients was 100.8 %. Mean assay results were 101.3 % (n = 3). The assay results are comparable to those obtained by the compendial liquid chromatographic method. - J. Assoc. Off. Anal. Chem. 71, 528-530 (1988). Reid-Rowell, Anal. Res. Dev., Marietta, o a (USA)

412 3 Biochemical and clinical analysis

Stopped-flow fluorimetric determination of theophyiline in pharmaceutical preparations. M". C. Guti6rrez, A. Gbmez-Hens and D. P6rez-Bendito.

The reaction of theophylline with cerium(IV) has been applied to the kinetic-fiuorimetric determination of theophilline using a simple and versatile modular stopped-flow system. The method is based on the monitoring of the variation in the fluorescence intensity during the formation of a 1:1 compound between the oxidation product of theophilline and cerium(III). The stopped-flow technique provides the data required to determine the reaction rate from each kinetic curve in only 8 s. The linear range of the proposed method is 1 -250 pg m1-1 of theophylline and the detection limit is 0.95 gg m1-1. The stopped- flow method has been satisfactorily applied to the determination of theophylline in various pharmaceutical preparations. Analytical recover- ies are in the range 95.0-102.0%. - Analyst 113, 559-562 (1988). Dept. Anal. Chem., Fac. Sci., Univ., C6rdoba (E)

Determination of reserpine and hydrochlorothiazide in commercial tablets by liquid chromatography with fluorescence and UV absorption detectors in series. U.R. Cieri.

A procedure is presented for the determination of reserpine and hydrochlorothiazide in commercial tablets by LC. Reference and sample solutions are prepared in methanol. For LC, a normal phase column is used, methanol is the eluting solvent, and 2 detectors are arranged in series. A fluorescence detector set at an excitation wavelength of 280 nm and emission wavelength of 360 nm quantitates reserpine, and a UV absorption detector set at 345 nm determines hydrochlorothiazide. Sev- eral synthetic mixtures and commercial tablets containing the 2 ingredi- ents were analyzed by the proposed method. - J. Assoc. Off. Anal. Chem. 71, 515-518 (1988). Food Drug Admin., Philadelphia, PA (USA)

Determination of the evaporation rate of essential oils and perfumery compositions using gas chromatography. T.A. Rudolf, M.M. Shchedrina and L.O. Mindlin.

Die Methode zur Bestimmung der Verdampfungsrate yon/itherischen Olen und Parfimgemischen basiert aufder GC mit Temperaturprogram- mierung und ist vergleichbar der simulierten Destillation. Es wird eine kurze Capillars/iule benutzt, die jedoch nicht mit einer flfissigen Phase beschichtet ist. Die Ergebnisse werden dargestellt als Beziehung zwischen Sfiulentemperatur und dem prozentualen Anteil der verdampften Probe. - Chromatographia 25, 520-522 (1988). All-Union Res. Inst. Natural Synthetic Odour Substances, Moscow (SU) M.J. Rittich

Flavor characterization of dentifrices using kinetic headspace gas chroma- tography. E.A. Tavss, S.G. Wiet, R.S. Robinson, J. Santalucia and D.L. Carroll.

A new instrumental technique, kinetic headspace gas chromatography (KHS-GC), was developed to measure relative quantity and composition of flavor released from dentifrices into the headspace of sealed vials, before equilibrium was attained. Dentifrice formulations varying in com- position or processing were analyzed for volatile flavor components, providing a quantitative instrumental determination of the effect of these factors on flavor. High correlations were found between the results of the KHS-GC procedure and human perceived flavor attributes of dentifrices as determined by trained sensory panelists. This method has applications in a wide array of product categories, such as foods, beverages and personal care products. - J. Chromatogr. 438, 2 7 3 - 280 (1988). Colgate-Palmolive Comp., Res. Developm. Div., Piscataway, NJ (USA)

Stabillty-indicating liquid chromatographic determination of alpha-ionone in toothpaste. RJ. Trivedi.

A simple, sensitive, and rapid liquid chromatographic method for quantitating c~-ionone in toothpaste at levels of 20 ppm in the presence of large amounts of flavor has been developed. 10 pin C ls packing and methanol/acetonitril/0,01 M K2HPO4 (35:20:45) as mobile phase are used. The method is accurate, precise, cost-effective, and specific for a c~-ionone. Average recovery of a laboratory-prepared sample was 99.0% with the relative standard deviation was 1.29% (n = 6). - J. Assoc. Off. Anal. Chem. 71, 3 6 - 3 7 (1988). Warner-Lambert, Consum. Prod. Res. Dev. Cent., Morris Plains, NJ (USA)

Determination of thioglycofie acid, dithiodiglycofic acid, cysteine and cystiae in hair-waving solutions by HPLC. J. Koyama, T. Matsumoto, Y. Ohtsu and O. Nakata.

A rapid and simple method by using HPLC was developed for the determination of thioglycolic acid, dithiodiglycolic acid, cysteine and cystine in hair-waving solutions. Ion pair method was suitable for the separation of these ingredients. HPLC conditions used for the separation were: column packing and size, CAPCELL PAK C18 and 4.6 mm i.d. x 250 mm; mobile phase, a mixture of 5% acetonitrite-95% water containing 0.1% phosphoric acid and 3.5 mM l-heptanesulfonic acid; detection, UV 210 rim. Recoveries of these four ingredients from the model sample were 100 ~ I02%. p-Hydroxybenzoic acid (0.25 mg/5 ml) was added to 0.25 g of sample as an internal standard and then it was diluted to ca. 40 ml with water; 10 gl of this sample solution was injected into chromatograph. By using this method, the four ingredients in 9 commercial hair-waving solutions were accurately determined without interferences of other ingredients. - Bunseki Kagaku 37, 142-146 (1988) (Japanisch, mit engl. Zus.fass.). Shiseido Toxicol. Anal. Res. Center, Yokohama-shi, Kanagawa (J)

A method for the determination of N-nitrosoalkanolamines in cosmetics. H. Sommer and G. Eisenbrand.

Die N-Nitrosoalkanolamine werden sfiulenchromatographisch abge- trennt, silyliert und die TMS-Derivate gaschromatographisch analy- siert. - Arbeitsweise. 2 g Probe in 9 ml Wasser 16sen, 100 pl NEPHA als innerer Standard und 0,5 g Ammoniumsulfamat zuffigen und mit Natriumchlorid s/ittigen. Bei stabiler Emulsionsbildung pH mit NaOH auf 8 ,5 - 9,5 einstellen, 1,5 ml Chloroform zuftigen und Mischung fiber eine Kieselgurs/iule geben, mit 3 ml Wasser nachspiilen, /iquilibrieren (20 min), mit 100 ml Cyclohexan/Dichlormethan (1:1) auswaschen und mit 150 ml n-Butanol eluieren. Unter steigendem Vakuum im Rotations- verdampfer bei 40~ abdampfen, Rfickstand in 20 ml Chloroform/Ace- ton (5:1) aufnehmen, fiber eine Kieselgelsfiule geben und mit dem L6- sunggsmittel bis zu 80 ml Gesamtvolumen nachspfilen. Mit 50 ml Aceton eluieren, im Rotationsverdampfer auf 5 ml einengen und mit Aceton in einen Kolben iiberspfilen: L6sungsmittel im Stickstoffstrom entfernen. Silylierung. Rfickstand mit 150 pl MSHFBA versetzen und nach 45 min mit i-Octan zu 0,5 ml ergfinzen. Externer Standard: 100 ng NDELA plus NEPHA; L6sungsmittel unter Stickstoff entfernen und derivatisieren. GC. App. Hewlett Packard 5880 A mit TEA; 3 m x 2 mm-S/iule (silani- siertes Glas) mit 6% OV 275 an Volaspher A 2. Tr/igergas Helium (20 ml/min), angewandte Menge 5 pl. Injektionstemperatur 200~ Tempe- raturprogrammierung 150~ (1 rain), dann bis 170~ (2~ bis 220~ (10~ Pyrolysetemperatur 400-500~ Wiederauffindung innerer Standard 95%, Erfassungsgrenze 5 p.g/kg. - Z. Lcbensm. Un- ters. Forsch. 186, 235-238 (1988). Fachrichtg. Lebensm.chem. u. Um- welttoxik., Fachber. Chem., Univ., Kaiserslautern (D) D. Rittweger

3 BIOCHEMICAL AND CLINICAL ANALYSIS

Pressurized microwave digestion of biological samples for metal determi- nation. I. Kojima, T. Uchida and C. Iida.

The utility of microwave oven for simple and rapid acid digestion of zoological and botanical materials was investigated by using a double Teflon vessel with a polypropylene jacket. The microwave-assisted diges- tion of samples with the HNO3-HC1-HC104-HF mixture in the bomb offers the advantage of taking much shorter process for sample prep- aration. The digestion was completed within 15 rain even under a very mild condition. Eight elements (Cu, Fe, Mn, Zn, Ca, Mg, K and Na) in the standard reference materials were determined by one-drop flame atomic absorption and emission spectrometry. Good agreement with the certifed values was obtained. - Anal. Sci. 4, 211-214 (1988). Lab. Anal. Chem., Dept. Appl. Chem., Nagoya Inst. Technol., Nagoya (J)