Electrocatalytic Oxidation Study of Theophylline on a Copper Nanoparticles-Modified, Carbon Paste Electrode Based on Cyclic Voltammetry

In this study, the Cu nanoparticles were prepared by reducing CuSO4. These particles were used in making copper nanoparticles modified carbon paste electrode (nano-CPE). The electrochemical characteristics of this electrode (nano-CPE) were investigated. The results of the electrocatalytic oxidation of theophylline (TP) on nano-CPE, using the cyclic voltammetry technique showed that nano-CPE, has more reactivity and more effective surface area, as compared to the unmodified carbon paste electrode (un-CPE). The investigation of voltammograms obtained from oxidation of TP at different scan rates on the nano-CPE confirmed a cyclic mediated redox mechanism followed by reducing Cu(III) which is a chemical reaction (EC mechanism). These species formed in more positive potentials and act as a redox intermediate for TP oxidation. There was a linear relationship between the oxidation peak current and the square root of the scan rate, showing that the oxidation reaction of TP at nano-CPE might be due to the diffusion-controlled process.