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

Abstract

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 (2.28×103M−1s−1) using chronoamperometry. The square wave voltammetric (SWV) peak currents of the electrode increased linearly with the corresponding CAP concentration in the range of 5.0×10−8M–8.0×10−4M with a detection limit of 1.0×10−8M.