Electrochemical Recognition of Phenylalanine Enantiomers Based on Silver Nanoparticles Modified Aminated Carbon Nanotubes

Abstract

By utilizing β-cyclodextrin (β-CD) and bovine serum albumin (BSA) as chiral selectors, a simple method was employed to fabricate an electrochemical sensor that modified with aminoized multiwall carbon nanotubes (NH2-MWCNT) and silver nanoparticles (AgNPs). The appearance and structure of the chiral sensor were characterized through X-ray powder diffraction, scanning electron microscopy, transmission electron microscope, Fourier transform infrared spectroscopy, ultraviolet–visible spectrophotometer, and X-ray photoelectron spectroscopy. The electrochemical chiral recognition behavior of the phenylalanine (Phe) enantiomer was achieved by differential pulse voltammetry. The working chiral recognition is based on the “three-point action principle.” The hydrogen bond between chiral selectors and Phe is the key to chiral recognition. Under the optimal experimental conditions, the oxidation peak current ratio of D-Phe to L-Phe (ID/IL) was 1.71. In the linear range of 3–15 mM, the detection limits of D-Phe and L-Phe are 4.62 and 5.23 μM (S/N = 3), respectively. It is noteworthy that the sensor possessed good stability and reproducibility.