Perylene-functionalized graphene sheets modified with chitosan for voltammetric discrimination of tryptophan enantiomers

• DOI: 10.1007/s00604-019-3442-5
• Publication Date: 2019-05-07T17:36:16Z
• Authors: Xing Yang; Xiaohui Niu; Zunli Mo; Ruibin Guo; Nijuan Liu; Pan Zhao; Zhenyu Liu
• Keywords: Chitosan; Tryptophan; Reproducibility of Results; Stereoisomerism; Biosensing Techniques; Electrochemical Techniques; 02 engineering and technology; Limit of Detection; Calibration; Graphite; 0210 nano-technology; Electrodes; Perylene

A composite was prepared from graphene functionalized with 3,4,9,10-perylene tetracarboxylic acid and chitosan (rGO-PTCA-chitosan) by a chemical method. It involves non-covalent functionalization of rGO with PTCA followed by amidation reaction with chitosan. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and electrochemical methods were used to characterize the composites. By combining the chiral features of chitosan and the excellent electrochemical behaviors of rGO-PTCA, a graphene-based material with enantioselectivity was constructed for electrochemical chiral recognition of tryptophan (Trp) enantiomers. A glassy carbon electrode (GCE) modified with rGO-PTCA-chitosan had a higher recognition capability for L-Trp than for D-Trp. Best operated at a working voltage near 0.78 V (vs. SCE), the enantioselectivity coefficient is 3.0. The sensor has a linear response in the 1 mM to 10 mM Trp concentration range and a 1.2 μM detection limit (at S/N = 3) for L-Trp, and of 3.0 μM to D-Trp. The sensor was successfully used to detect Trp enantiomers in real samples, and a recognition mechanism is presented. Graphical abstract Schematic presentation of a composoie prepared by graphene functionalized with 3,4,9,10-perylene tetracarboxylic acid and chitosan (rGO-PTCA-chitosan) via a chemical method. It involves non-covalent functionalization of rGO with PTCA followed by amidation reaction with chitosan and voltammetric determination of tryptophan enantiomers.