Self-assembled reduced graphene oxide/polyaniline/sodium carboxymethyl cellulose nanocomposite for voltammetric recognition of tryptophan enantiomers

A nanocomposite was synthesized from reduced graphene oxide (rGO), polyaniline (PANI), and carboxymethyl cellulose (CMC) as the initial materials by in situ polymerization. The substrate rGO provides many active sites for in situ polymerization of aniline and self-assembly of CMC. Scanning electron microscopy, X-ray diffraction, thermogravimetry, Raman, Infrared Spectroscopy, and X-ray photoelectron spectroscopies were used to characterize the morphology, electronic structure, and composition of different materials. The nanocomposite was used to modify a glassy carbon electrode (GCE) to obtain a sensor for chiral electrochemical recognition of tryptophan enantiomers. Their electrochemical properties and recognition abilities were investigated using cyclic voltammetry and differential pulse voltammetry, and the final consequence demonstrated that the modified GCE could well distinguish l-tryptophan and d-tryptophan. The enantiomeric selectivity is 2.26. The GCE was successfully used for the recognition of d-tryptophan and l-tryptophan in spiked serum and urine samples.