An Electrochemical Sensor for L-Tryptophan Using a Molecularly Imprinted Polymer Film Produced by Copolymerization of o-Phenylenediamine and Hydroquinone

Abstract

An electrochemical sensor for L-tryptophan based on a molecularly imprinted polymer was developed. The sensing film was prepared by the co-electropolymerization of o-phenylenediamine and hydroquinone on a gold electrode in the presence of L-tryptophan as the template. The performance of the L-tryptophan sensor was characterized by cyclic voltammetry, differential pulse voltammetry, and alternating current impedance. Under the optimal experimental conditions, the relative current change was linear to the concentration of L-tryptophan in the range of 1.0 × 10−8 to 1.0 × 10−6 mol/L and a detection limit of 0.50 × 10−8 mol/L was obtained. The sensor showed high sensitivity and selectivity for L-tryptophan. The imprinting factor was 3.58 and selectivity factors of L-tryptophan compared to analogs were larger than 2. The sensor also demonstrated good resistance to acidic, basic, and organic environments.