Voltammetric sensor based on Co3O4/SnO2 nanopowders for determination of diltiazem in tablets and biological fluids

In this work, an anodic stripping voltammetry for nanomolar determination of diltiazem with a chemically modified carbon paste electrode (CMCPE) containing Co3O4/SnO2 nanopowders was studied. The accumulation potential and time were selected at, -0.2 V and 190 s, respectively. The electroanalytical performance of the CMCPE was evaluated regarding the carbon paste composition, the solution pH, the time and potential accumulation, and the potential interferences. The novel electrode showed linear response to diltiazem concentration range of 50-650 nM with a lowest detection limit value of 15 nM. The precisions for six consecutive determinations of 350 and 550 nM diltiazem were 3.2 and 2.5 %, respectively. It was demonstrated that the proposed method was free from most interference. Finally, the method was effectively applied to the determination of diltiazem in pharmaceutical tablets and biological samples.