Determination of captopril in pharmaceutical forms by stripping voltammetry

A voltammetric procedure is developed for determining captopril in pharmaceuticals. It is based on the preliminary electrochemical accumulation of the captopril oxidation product on a platinum electrode in a 0.1 M HNO3 solution at 1.2 V versus a saturated silver-silver chloride electrode. The reduction current of the oxidation product is a linear function of captopril concentration in the range from 1.2 x 10(-6) to 3.2 x 10(-4) M. The determination limit is 9.2 x 10(-7) M. The relative standard deviation is between 1 and 4%.