Interdigitated Array Diffusion Layer Titration of Dithiocarbamates with Electrogenerated Hypobromite

A simple but sensitive technique was developed for determination of dithiocarbamates. The proposed method is based on its oxidation with hypobromite under the formation of sulfate. The oxidation proceeds only in the close vicinity of interdigitated array microelectrode (IDA), the segments of which were used as working and indicator electrodes. Hypobromite was formed by disproportionation of galvanostatically generated bromine (from bromide) in weakly alkaline solution on one segment of IDA (generator). The unreacted flux of hypobromite was amperometrically detected on the second segment (collector-indicator). The hypobromite flux is influenced by dithiocarbamates present in solution, causing changes in the collector versus generator current plot (titration curve) which can be quantitatively evaluated. The sensitivity of the method is 7 795 l mol-1 μA and detection limit estimated according to the 3s criterion is 2.2 · 10-6 mol l-1. The technique was used in analysis of real samples, such as in determination of a pesticide residues in cucumber leaves.