▎ 摘　　要

A practical sensor based on a glassy carbon electrode (GCE) modified with exfoliated graphene (GR) and poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT:PSS) was prepared to determine L-tryptophan (L-Trp) via differential pulse voltammetry (DPV). Optical microscopy was utilized to characterize the surface morphology of the composite electrode. Electrochemical behaviors of the composite electrodes were carried out via cyclic voltammetry (CV). According to DPV results, there are linear relationships between the peak currents and the concentrations in the ranges of 0.1-100 mu mol L-1 and 100-1000 mu mol L-1 for L-Trp, with the detection limit of 0.015 mu mol L-1 for L-Trp. Moreover, the modified electrode can eliminate the interference effects of Ca2+, Mg2+, K+, Na+, L-tyrosine and ascorbic acid, which exhibit excellent stability and reproducibility.