Nanostructured Conducting Polymer/Copper Oxide as a Modifier for Fabrication of L-DOPA and Uric Acid Electrochemical Sensor

A modified electrode was prepared by modification of the carbon paste electrode (CPE) with a nanostructured material. This nanostructure with electrocatalytic activity was synthesized by combination of poly pyrrole and copper oxide nanoparticles (PPy/CuO). The structure and morphology of PPy/CuO was studied. The fabricated modified electrode (CPE-PPy/CuO) exhibited an excellent electrocatalytic activity toward levodopa (L-DOPA) and uric acid (UA) oxidation because of high conductivity, low electron transfer resistance and catalytic effect. The CPE-PPy/CuO had a lower overvoltage and enhanced electrical current with respect to the bare CPE for both L-DOPA and UA. Also, the modified electrode showed a good resolution for the overlapped anodic peaks of L-DOPA and UA. This electrode was used for the successful simultaneous determination of L-DOPA and UA. The electrochemical sensor responded to L-DOPA and UA in the concentration range of 0.050-1200 mM and 0.040-2000 mM, respectively. The detection limits were obtained by differential pulse voltammetry as 15 nM for L-DOPA and 20 nM for UA. Finally, the proposed electrode was used for determination of L-DOPA and UA in real samples using standard addition method.