DETERMINATION OF 2-THIOTHIAZOLIDINE-4-CARBOXYLIC ACID IN URINE BY LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

An assay procedure utilizing liquid chromatography and amperometric detection at a chemically modified electrode (CME) has been developed for the determination of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine samples. The electrocatalytic activity of the CME, which consisted of a glassy carbon surface coated with an electropolymerized cobalt phthalocyanine film, permitted optimum response at a potential of +0.75 V vs. Ag/AgCl with a detection limit of 7 pmol for TTCA and with no sample preparation required. In case of fouling of the electrode surface by sample constituents, the polymeric cobalt phthalocyanine electrode surface could be renewed with a variability of less than 10% and an equilibration time of less than 15 minutes.