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A sensitive micro method for the manual estimation of true glucose in 10 mul plasma by an enzymatic technique is described. Protein precipitation is avoided. The method is simple to perform, accurate and precise. Agreement with a glucose oxidase autoanalyzer method is excellent, even with haemolysed and icteric specimens.

A rapid, accurate microtechnique has been developed for gas chromatographic determination of the fatty acid composition of small (2-3 micro l) samples of vegetable oils. This microtechnique combines transesterification and sample injection into a single operation. The fatty acid compositions of soybean, linseed, and safflower oils thus determined are compared with those obtained by the usual two-step procedure.

The product of beta-lactamase activity (a penicilloic acid in the case of a penicillin) is stoichiometrically oxidized by iodine. Hence, the beta-lactamase activity can be measured as decolorization of the blue starch-iodine complex. Since the decolorization is a slow process, the rate of decolorization gave an underestimate of the rate of penicillin hydrolysis until a steady state was obtained after 15 to 20 min. If the reaction mixture (3 ml) contained no more than 0.001 unit of enzyme, a correct determination of beta-lactamase activity was obtained from the microiodometric method described. The method is sensitive and some applications are mentioned.

The microiodometric assay of Novick for penicillinase was adapted to the Technicon Autoanalyzer system. With this automated method, it is possible to analyze almost 60 samples per hr. Two different procedures are described: in the first, the samples were incubated with substrate in the machine under standardized conditions; in the second, samples were incubated outside the Autoanalyzer and assayed at intervals for penicilloic acid. As little as 5 mum penicilloic acid could easily be detected in a sample of 0.4 ml. The reproducibility was very good. The hydrolysis of penicillin in a suspension of nongrowing bacteria as well as in a growing culture could also be followed. The automated method has been used both for kinetic studies and in screening for activity in eluates from column chromatography experiments.