A feasible and efficient voltammetric sensor based on electropolymerized L-arginine for the detection of L-tryptophan in dietary supplements

•An efficient voltammetric sensor was developed for L-tryptophan detection.•The sensor was based on the electropolymerization of L-arginine on glassy carbon electrodes.•The electropolymerization conditions were studied and optimized using chemometrics.•The presence of the polymeric coatings enhanced the electrode’s sensitivity.•The sensor successfully detected L-tryptophan in commercial dietary supplements.