An electrochemical chiral sensor for tryptophan enantiomers based on reduced graphene oxide/1,10-phenanthroline copper(ii) functional composites

Abstract

An electrochemical chiral sensor based on reduced graphene oxide (RGO) non-covalently functionalized with 1,10-phenanthroline copper(II) (PhenCu) complex has been developed for electrochemical discrimination of tryptophan (Trp) enantiomers. The formation and morphology of reduced graphene oxide/1,10-phenanthroline copper(II) (RGO/PhenCu) composites were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Cyclic voltammetry (CV) was employed to monitor the electrochemical behavior of RGO/PhenCu immobilized on glassy carbon electrode (RGO/PhenCu/GCE). The reduction in peak current was significantly different when the chiral sensor interacted with L-Trp and D-Trp. This suggested that RGO/PhenCu/GCE could be used as an electrochemical chiral sensor for the discrimination of Trp enantiomers. Further studies showed that the peak current decreased linearly along with an increasing percentage of L-Trp in the Trp mixture. The RGO/PhenCu/GCE electrochemical chiral sensor, with rapid recognition, good sensitivity and high stability, provided an efficient method to recognize and discriminate Trp enantiomers.