vi SUMMARIES OF PAPERS IN THIS ISSUE [June, 1974Summaries of Papers in this IssueA Direct Gas -chromatographic Method for the Determination of BasicNitrogenous Drugs in Pharmaceutical PreparationsA gas-chromatographic method has been developed for the direct assayof basic nitrogenous drugs, present as salts, in a range of pharmaceuticalpreparations. A glass column was packed with 3 per cent. silicone OV-17 onGas-Chrom Q, 80 to 100 mesh, and maintained isothermally a t temperatureswithin the range 200 to 270 "C, as appropriate for the drug to be determined.Calibration data are given for eighteen drugs, and the gas-chromatographicprocedures have been subjected to a statistical evaluation. Five determina-tions performed on each of eight standard pharmaceutical preparations gavecoefficients of variation of less than 2.2 per cent.The subsequent applica-tion of the method, based upon duplicate determinations, to a larger series ofstandard pharmaceutical preparations gave recoveries within the range 96 to104 per cent. of the known concentration of the test drug. The procedurecan now be used as part of a routine quality control specification in place ofa variety of non-specific classical methods.N. D. GREENWOOD and I. W. GUPPYRegional Quality Control Laboratory, Pharmacy Department, Leeds GeneralInfirmary, Great George Street, Leeds, LSl 3EX.Analyst, 1974, 99, 313-325.A Method for the Determination of Volatile Fatty Acids in the BloodPlasma of Ruminant AnimalsAn improved method for the determination of volatile fatty acids in theblood plasma of ruminant animals is described.The acids are extracted astheir sodium salts with isopropyl alcohol and then dissolved in 9 + 1 diethylether - formic acid for determination by gas - liquid chromatography.J. W. GARDNER and G. E. THOMPSONDepartment of Physiology, The Hannah Research Institute, Ayr, KA6 5HL,Scotland.Analyst, 1974, 99, 326-329.Quantitative Determination of the Enantiomeric Purity ofSynthetic PyrethroidsPart 11. S-BioallethrinS-Bioallethrin consists primarily of ( + )-allethronyl-( + )-trans-chrysanthe-mate, but technical samples contain small amounts of other allethrin isomers.The ratio of diastereoisomers can be measured directly from the nuclearmagnetic resonance spectrum after using a europium shift reagent, whenmany of the resonances split into two distinct diastereoisomer signals.If theenantiomeric purity of the chrysanthemate moiety is determined independently,then the absolute enantiomeric purity of the allethrin sample can be calcu-lated. Standard deviations for the measurement of laboratory or technicalsamples were between 0.3 and 0.7 per cent.The accuracy of the method was verified by independently determiningthe enantiomer ratios of various allethrolone samples by gas chromato-graphy of their diastereoisomeric ( - )-a-methoxy-a-trifluoromethylphenyl-acetic esters, esterifying with natural ( + ) -trans-chrysanthemic acid and re-determining the enantiomeric purity by nuclear magnetic resonance.Goodagreement was achieved between the two determinations.The nuclear magnetic resonance method should also be suitable formeasuring the diastereoisomer ratio of cis-allethrins.F. E. RICKETT and P. B. HENRYWellcome Research Laboratories (Berkhamsted), Berkhamsted Hill, Berkhamsted,Hertfordshire.Analyst, 1974, 99, 330-337June, 19741 SUMMARIES OF PAPERS I N THIS ISSUEThe Detection and Determination of Polynuclear AromaticHydrocarbons by Luminescence Spectrometry Utilising the Shpol’skiiEffect at 77 KThe luminescence emission spectra of twenty-three polynuclear aromatichydrocarbons (PAH) have been examined in n-alkane solvents a t 77 K. TheShpol’skii effect, in which narrow-band (quasi-linear) emission spectra areobtained under these conditions when a monochromator of adequate resolvingpower is used, is shown to be readily observed for twelve of the compoundsexamined in these solvents.Quasi-linear emission spectra have also beenobtained in tetrahydrofuran for some of the PAH compounds examined.These emission spectra provide for unambiguous qualitative identification ofPAH compounds a t trace concentrations in solution; this effect is demon-strated by identification of the compounds present in an eight-componentmixture of PAH compounds.Measurement of the low-temperature quasi-linear luminescence intensitycan be applied quantitatively to the determination of these compoundsprovided that a standard additions procedure is employed in conjunctionwith the use of an internal standard to ensure sufficient accuracy and precision.G.F. KIRKBRIGHT and C. G. de LIMAChemistry Department, Imperial College, London, S.W.7.Analyst, 1974, 99, 338-354.viiApplication of the Spectrophotometric Determination of Nickel andCobalt in Mixtures With Bipyridylglyoxal Dithiosemicarbazone tothe Analysis of CatalystsBipyridylglyoxal dithiosemicarbazone forms a complex with nickel( 11)a t pH 5.2, which can be extracted into chloroform (Amax. = 410 nm). Asimilar complex is obtained with cobalt(II), but is not extractable in thissolvent, thus allowing nickel and cobalt to be determined in mixtures. Twoprocedures are proposed for the accurate analysis of such mixtures in which1 p.p.m. of one of the ions can be determined accurately in the presenceof as much as 6 p.p.m. of the other. One of the procedures has been appliedto the determination of nickel and cobalt in industrial catalysts and theresults obtained have been compared with those obtained by atomic-absorp-tion spectrophotometry. Satisfactory results were obtained.J. L. BAHAMONDE, D. PEREZ BENDITO and F. PIN0Department of Analytical Chemistry, University of Seville, Seville, Spain.Analyst, 1974, 99, 355-359