Electrocatalytic determination of captopril using NiO nanoparticle/acetylferrocene modified electrode in biological and pharmaceutical samples

The electrocatalytic oxidation of captopril (CAP) has been studied by acetylferrocene (AF) modified NiO/NPs carbon paste electrode (AF/NiO/NPs/CPE). Cyclic voltammetry (CV), square wave voltammetry (SWV) and chronoamperometry were used to investigate the suitability of AF as a mediator for the electrocatalytic oxidation of CAP in aqueous solution. The catalytic reaction rate constant, kh was calculated (2.539 × 103 M−1 s−1) using chronoamperometry. The square wave voltammetric (SWV) peak currents of the electrode increased linearly with the corresponding CAP concentration in the range of 0.3–450 µM with a detection limit of 0.09 µM. The proposed sensor was used for determination of captopril in tablet and urine samples.