Chiral recognition of tyrosine enantiomers on a novel bis-aminosaccharides composite modified glassy carbon electrode

A polyaminosaccharide (chitosan, CS) and an aminosaccharide (D-galactosamine, GaIN) were integrated together via hydrothermal assembly to obtain a bis-aminosaccharides composite (CS-GaIN), and a novel and facile chiral sensing platform based on CS-GaIN modified glassy carbon electrode (CS-GaIN/GCE) was fabricated and used for electrochemical recognition of tyrosine (Tyr) enantiomers. CS-GaIN composite was characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and contact angle goniometry. It was observed that CS-GaIN composite exhibited different binding ability for Tyr enantiomers. Under optimized experimental conditions, the oxidation peak current ratio of L-Tyr to D-Tyr (I-L/I-D) and the difference between their peak potentials (Delta Ep = E-D-E-L) were 1.70 and 28 mV at CS-GaIN/GCE by square wave voltammetry (SWV). In addition, the peak currents increase linearly with the concentration of Tyr enantiomers in the concentration range 0.01-1.00 mM with detection limits of 0.65 mu M and 0.86 mu M for L-Tyr and D-Tyr (S/N= 3), respectively. CS-GaIN/GCE also exhibited the ability to determine the percentage of D-Tyr in the racemic mixture. In addition, CS-GaIN/GCE possessed remarkable sensitivity, great stability as well as fine reproducibility. It could be concluded that the chiral interface of CS-GaIN/GCE can provide an ideal platform for electrochemical recognition and determination of Tyr enantiomers. (C) 2019 Elsevier B.V. All rights reserved.