Chiral Recognition of Phenylglycinamide Enantiomer Based on Electrode Modified by Silver-Ammonia Ion-Functionalized Carbon Nanotubes Complex

Abstract

Polyacrylic acid (PAA) chains were used to decorate the surface of multi-walled carbon nanotubes (MWCNTs) via in situ free radical polymerization, and sulfonated chitosan (SCS) was synthesized via a simple and environmental method. Silver-ammonia ions were introduced as the fixative with PAA-MWCNTs as the basic framework, and SCS was used to decorate the surface, thereby obtaining PAA-MWCNTs-Ag-SCS. The modified electrode exhibited excellent cyclic voltammogram (CV) stability after 100 cycles of scanning. According to differential pulse voltammetry (DPV), the peak current value was approximately 250 μA, exhibiting outstanding sensitivity to phenylglycinamide (Pen) enantiomers. The peak current ratio of D-Pen to L-Pen reached 2.16, showing excellent selectivity. The detection limit (DL) was calculated as 0.015 mM and 0.036 mM for L-Pen and D-Pen, respectively, using the signal-to-noise ratio (S/N = 3). This study provides a new idea for the construction of a chiral-sensing platform with outstanding sensitivity, superior stability, and excellent recognition efficiency.