Selective detection by depleting interferent in diffusion layer based on a combination of pre-depletion pulse and differential pulse voltammetry

A method for selective detection based on the concept of electrochemical depletion of interfering species in diffusion layer is proposed. By applying an appropriate pre-depletion pulse (PDP) to the working electrode, interfering species is oxidized and thus an interferent-depleted micro-environment is created in diffusion layer. Then a follow-up differential pulse voltammetry (DPV) is utilized for detecting target analyte. The feasibility of the method is verified by detecting dopamine in the presence of ascorbic acid. The results demonstrate that the detection limit is improved by more than an order of magnitude compared with that of the method of combining potential step with linear sweep voltammetry, owing to the ability of differential pulse voltammetry to eliminate background current. Experimental parameters affecting the dopamine detection are investigated systematically. Because only easily achievable potential control and commonly used electrode without modification are required, the proposed method is facile and thus high reproducibility is expected.