An electrochemical method for selective detection of dopamine by depleting ascorbic acid in diffusion layer

A facile method for selective detection based on the concept of electrochemical depletion of interfering species in diffusion layer was established. The feasibility of the method was verified by detecting dopamine in the presence of ascorbic acid. By applying a proper step potential to working electrode, at which interfering species, ascorbic acid, is oxidized while dopamine is kept unconsumed, an interferent-depleted region is thus created in the diffusion layer of the working electrode. Then the target analyte is detected by applying a follow-up linear sweep voltammetry with faster sweep rate to ensure the amount of the interfering species that diffuses to the electrode surface is negligible. The influence of step potential, step duration and sweep rate on dopamine detection has been systematically investigated. Since the proposed method only requires easily achievable potential control and commonly used electrode without modification, it is facile and thus high reproducibility is expected.