Sensitive and selective determination of dopamine by electrochemical sensor based on molecularly imprinted electropolymerization of o-phenylenediamine

A sensitive and selective sensor was developed for dopamine (DA) determination based on a molecularly imprinted electropolymer of o-phenylenediamine (OPD). A very small quantity of biocompatible sulfonated graphene was modified onto Au electrode to enhance the current response. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the molecular imprinted (MIP) sensor. Several important parameters controlling the performance of the molecularly imprinted sensor were investigated and optimized. Under optimum condition, DA can be determined in the range of 0.5-7.0 mg L-1 and the low detection limit is 0.11 mg L-1. Ascorbic acid (AA) almost did not interfere in the determination of DA when the concentration molar ratio of 50 : 1. The prepared sensor had been applied to the analysis of DA in human serum samples with satisfactory results. It also showed stable reproducibility and can be easily fabricated at low cost.