ELECTROCHEMICAL STUDY OF THE OXIDATION OF CARBIDOPA AND ITS DETERMINATION USING LIQUID-CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

The electrochemical oxidation of carbidopa [(S)-(-)-2-(3,4-dihydroxybenzyl)-2-hydrazinopropionic acid monohydrate] was studied by linear sweep voltammetry, cyclic voltammetry, microcoulometry and preparative electrolysis. An ECCE mechanism with two-electron transfer, followed by two chemical reactions (decarboxylation and hydrolysis), were found, giving carbon dioxide, hydrazine and 3,4-dihydroxyphenylacetone. The final electrochemical step may be a reversible two-electron oxidation process which gives the o-quinoidal analogue of the latter. An analogous oxidation mechanism was found when carbidopa was oxidized with HBrCl2 in hydrochloric acid.