Electrochemical Oxidation of Sulfamethazine on Multi-Walled Nanotube Film Coated Glassy Carbon Electrode

The electrochemical oxidation of sulfamethazine (SMZ) has been studied at a multi-walled carbon nanotubes modified glassy carbon electrode (MWCNT-GCE) by cyclic voltammetry. This modified electrode (MWCNT-GCE) exhibited excellent electrocatalytic behavior toward the oxidation of SMZ as evidenced by the enhancement of the oxidation peak current and the shift in the anodic potential to less positive values (170 mV) in comparison with the bare GCE. The formal potential, E0'', of SMZ is pH dependent with a slope of 54 mV per unit of pH, close to the anticipated Nerstian value of 59 mV for a 2-electron and 2-proton oxidation process. A detailed analysis of cyclic voltammograms gave fundamental electrochemical parameters including the electroactive surface coverage (Г), the transfer coefficient (), the heterogeneous rate constant (ks). Under the selected conditions, the peak current shows two dynamic linear ranges of 10-200 M and 300-3000 Mwith the detection limit of 6.1 M. The method was successfully applied to analyze SMZ in serum sample.