A gas chromatographic method is described for the determination of linear alkylbenzenesulfonate (LAS). LAS was converted into its N-methylanilide derivative by a convenient procedure involving ion-pair extraction followed by amidation, and was analyzed by electron-capture gas chromatography (ECD-GC) using 0.5% OV-17+0.1% FFAP on Uniport HP as the GC column packing. The derivative was very stable and provided excellent ECD response. By ECD-GC method, a linear calibration curve was obtained in the range of 5 -1000 ng of LAS. The detection limit of LAS was 0.1 ng as injection amount. LAS in river water could be measured without influence of co-existing substances. The recoveries of LAS in river water were 95 -109% and the reproducibility was found to be satisfactory. The LAS contents in river water samples were measured by ECD-GC method and Methylene Blue method, and the analytical results by both methods were compared.

The effects of various cephem antibiotics and related compounds on ethanol metabolism were studied in association with their chemical structures. In rats, cefoperazone, cefbuperazone, cefamandole, latamoxef, cefmetazole, cefotetan, cefmenoxime and cefminox which have the [(1-methyl-1H-tetrazol-5-yl) thio] methyl group at position 3 of the cephem ring caused a significant increase in the blood acetaldehyde concentration. In the last three compounds, disulfiram-like activity was less potent than that evaluated in the preceding compounds. Cefazolin and ceftezole having a 1H-tetrazol group at position 7 also showed a disulfiram-like activity. A single administration of 1H-tetrazol also increased the blood acetaldehyde concentration. Both blood ethanol and acetaldehyde values were increased significantly on administration of these drugs. In beagle dogs, cefoperazone induced a less remarkable but much more sustained increase in the blood acetaldehyde. These results indicate that the 1H-tetrazol group, as well as the [(1-methyl-1H-tetrazol-5-yl) thio] methyl group, is responsible for inducing a disulfiram-like action and that there is a difference in the potency of the disulfiram-like activity among the drugs having a [(1-methyl-1H-tetrazol-5-yl)thio] methyl group at position 3 of the cephem ring in relation to those in which the side chain is substituted at position 7.

No abstract