Electrocatalytic Oxidation of Cisapride at Carbon Paste Electrode Modified with Copper Sulfide Nanostructures

In the present study, a new carbon paste electrode chemically modified with copper sulfide nanostructures is constructed and used for the catalytic oxidation of cisapride. The voltammetric behavior and electrochemical reaction mechanism of cisapride have been investigated at modified electrode using cyclic voltammetry (CV), steady state polarization and differential pulse voltammetry. In CV studies, no oxidation response of cisapride can be seen at the unmodified electrode, but at the copper sulfide nanostructures modified carbon paste electrode (CSN-MCPE), a large anodic peak appears, indicating that the anodic oxidation of cisapride could be catalyzed at CSN-MCPE. This proves that the copper sulfide nanostructures bear the main role in electrocatalytic oxidation of cisapride. The kinetic parameter such as the electron transfer coefficient (α) and exchange current density (j0) for the modified electrode were calculated. The differential pulse peak current varied linearly with the concentration of cisapride in range of 9×10−8 to 15×10−6 mol L-1. The modified electrode can be prepared very easy and renewed in its surface by simple polishing. The reproducibility of the electrode response, based on six measurements during two month, was 3.23% for the slope of the calibration curve.