A sensitive Cu(salophen) modified screen-printed electrode for simultaneous determination of dopamine and uric acid

This research applied a nanostructured electrochemical sensor with a screen-printed electrode (SPE) for examining the dopamine (DA) electrocatalytic oxidation when uric acid (UA) was present. Cu(salophen) nanostructured modified SPE (Cu(salophen)/SPE) was employed to investigate the electrochemical behavior of DA. At optimal pH (pH 7.0), oxidation of DA at the modified electrode takes place at a potential around 100 mV less positive than at the unmodified SPE. Chronoamperometry was used to determine the diffusion coefficient of DA (D = 1.96x10(-5) cm(2) s(-1)). Differential pulse voltammetry (DPV) showed linear response in the range between 0.2-450.0 mu M for DA. The limit of detection (LOD) of DA was computed to be 0.05 mu M. Moreover, Cu(salophen)/SPE was employed for determining DA in the presence of UA using DPV. The DPV results showed that at the modified electrode, two well-separated oxidation peaks of DA and UA could be obtained at potentials of 180 and 325 mV, respectively. This separation forms the basis for the co-detection of these two materials on the surface of Cu(salophen)/SPE. This sensor was then employed to determine DA and UA in real specimens.