A simple method for modifying a glassy carbon electrode to simultaneously determine dopamine and ascorbic acid

The modification of a glassy carbon electrode by applying voltage pulses with a steep rise time led to a significant separation (about 210 mV) between the anodic oxidation peaks of ascorbic acid and dopamine. The limits of detection for ascorbic acid and dopamine were 8 and 3 μM, respectively, and the modified electrode retained its sensitivity for approximately 30 days. The peak separation effect was attributed primarily to oxygen-containing functional groups formed on the sp²-hybridized carbon framework during electrochemical functionalization and to covalent π–π interactions between the aromatic ring of dopamine and the basal plane of the glassy carbon electrode.