A new sensor for electrochemical determination of captopril using chlorpromazine as a mediator at a glassy carbon electrode

A new simple, selective and rapid cyclic voltammetric method is reported for the accurate and precise determination of captopril using chlorpromazine as a suitable electrocatalyst. It has been shown by cyclic voltammetry, single step chronoamperometry and electrochemical impedance spectroscopy that chlorpromazine can catalyze the oxidation of captopril in aqueous buffer solution and produces a sharp oxidation peak current at about 0.625 V vs. saturated calomel reference electrode. The catalytic oxidation peak current of captopril is linearly dependent on its concentration and enables the determination of captopril over the concentration range of 8-1000 mu M at pH 5.0, with a detection limit of 4.8 mu M. The relative standard deviation for the determination of 400 mu M captopril is 0.66% (n = 9). The influence of potential interfering substances on the determination of captopril was studied. The method was satisfactorily applied to the determination of captopril in real samples such as drug and urine.