Real-Time Electrochemical Detection of Uric Acid, Dopamine and Ascorbic Acid by Heme Directly Modified Carbon Electrode

Several simple electrochemical sensors were designed for three analytes, uric acid (UA), dopamine (DA) and ascorbic acid (AA) detection via electrolytic deposition of three functional materials heme, Fc(Cys)(2) and Fc-ECG onto glassy carbon electrodes (GCEs) without other medium. Characterization of the modified GCEs was conducted using SEM, TEM and DPV methods. Results showed that the heme/GCE demonstrated notable electro-catalytic capabilities, towards DA, AA, and UA oxidation in a solution of phosphate buffer. The current signals of DPV technique for three analytes shown up three defined oxidated peaks, the peak potential differences was 192 mV for AA and DA, and 142 mV for DA and UA. Under optimal conditions, it can be obtained linear responses for AA, DA and UA in the following concentration ranges: 10 to 50, 5 to 20, and 2.5 to 20 mu mol. L-1, and the limits of detection was calculated as 0.76, 0.50 and 0.63 mu mol. L-1, respectively. The results demonstrated that the heme directly modified GCE was a well-suited electrochemical sensor for determining UA, DA and AA in actual samples.