Abstract
A method for the micro amperometric determination of thiol-groups as small as from 0.1 to 1.0μ mole, corresponding to 10-100μg of cysteine, was devised. The thiol-group was titrated in ammoniacal solution in the stream of nitrogen with silver nitrate solution, using an ultramicroburette. The course of the titration and the end point was detected amper-ometrically using platinum vibrating electrode. The method was suitable for the determina-tion of a minute amount of thiol-groups, especially those found in plant tissues, which used to contain such substances as might otherwise disturb the determination. Contents of acid-soluble thiol compounds in etiolated mung bean seedlings at various stages of growth were determined by the method described here.