Enhanced Chiral Electrochemical Recognition of Tryptophan Enantiomers Using a Novel Triple-Layered GO/BSA/CS Modified Glassy Carbon Electrode

A novel chiral electrochemical sensor was fabricated and used for recognition of tryptophan (Trp) enantiomers. Graphene oxide (GO) was prepared by the modified Hummers' method. Moreover, the suspensions/solutions of GO, bovine serum albumin (BSA) and chitosan (CS) in deionized-distilled water were coated onto the surface of GCE by a layer-by-layer drop method, and the novel triple layered GO/BSA/CS composite modified glassy carbon electrode (GO/BSA/CS/GCE) was fabricated. The electrochemical recognition and quantification of the Trp enantiomers on the GO/BSA/CS/GCE were performed using differential pulse voltammetry (DPV). The Trp monomer concentrations exhibited a good linear relationship with the peak current values. The GO/BSA/CS/GCE exhibited good coefficients of determination (R ² _D-Trp = 0.98917 and R ² _L-Trp = 0.94824) for D- and L-Trp enantiomers in the concentration range of 1 to 8 mM, respectively. The GO/BSA/CS/GCE fabricated in this study exhibited superior recognition performance, good oxidation potential and current response signals for D- and L-Trp. The novel GO/BSA/CS/GCE fabricated in this study exhibited potential to be used as a convenient, fast and efficient chiral electrochemical sensor for qualitative and quantitative determination of Trp enantiomers.