Selective determination of dopamine using modified electrodes by differential pulse voltammetry

Abstract

Selective detection of dopamine (DA) shows physiological and pathological importance because DA was widely accepted as one of the most important neurotransmitters involved in physiological processes in the mammalian central nervous system and as a prognostic biomarker for many types of diseases. In this paper a highly sensitive electrochemical method for selective determination of DA in the presence of ascorbic acid (AA), one of the most potentially interferent coexisting in the cerebral systems, is investigated. Chemically modified gold electrodes with thin layers of cobalt (II)-porphyrins (CoP) were used and characterized for DA and AA selective preconcentration and detection. The presence of CoP was favorable for the affinity adsorption of DA. This led to the decrease in the oxidation potential of AA and the enhanced oxidation peak currents of DA at the CoP-modified Au electrode. By differential pulse voltammetry (DPV), the oxidation potentials of DA and AA, at the CoP-modified Au electrode in a binary mixture were found to be well resolved so their simultaneous determination could be achieved. Under the optimized experimental conditions in DPV technique both DA and AA reveal sensitive oxidation peaks for micromolar range of concentrations