Square wave voltammetric determination of captopril in liquid phase using N-(4-hydroxyphenyl)-3,5-dinitrobenzamide modified ZnO/CNT carbon paste electrode as a novel electrochemical sensor

The electrocatalytic oxidation of captopril (CAP) has been studied by N-(4-hydroxyphenyl)-3,5-dinitrobenzamide (N-HPDB) modified ZnO/CNT nanocomposite carbon paste electrode (N-HPDB/ZnO/CNTs/CPE). Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry were used to investigate the suitability of N-HPDB as a mediator for the electrocatalytic oxidation of CAP in aqueous solution. The catalytic reaction rate constant, kh was calculated (2.28 × 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 5.0 × 10− 8 M-8.0 × 10− 4 M with a detection limit of 1.0 × 10− 8 M.