An electrochemical sensor for enantiorecognition of tyrosine based on a chiral macrocycle functionalized rGO

Abstract

A novel chiral sensor was developed to produce the distinguishing response to the enantiomers of tyrosine (Tyr), with high sensitivity and selectivity. The electrochemical sensor was modified by the inorganic-organic nanohybrid material with the functionalization of reduced graphene oxide (rGO) to be the amplifier and a chiral hetero-multifarene[3,2,1] (CHMF[3,2,1]) as the chiral receptor. The as-prepared rGO-CHMF was characterized by transmission electron microscopy (TEM), atomic force microscope (AFM), infrared spectroscopy (IR), thermogravimetric analysis (TGA), Raman spectroscopy and electrochemical methods. It was observed that the composites exhibited different binding ability for Tyr enantiomers. The proposed sensor presented significant difference with peak potential separation value (ΔEp = 70 mV) and the ratio of peak current (IL-Tyr/ID-Tyr = 1.58) for Tyr enantiomers by differential pulse voltammetry. In addition, the peak currents increased linearly with the concentration of Tyr enantiomers in the concentration range 0.1–10 μM with detection limits of 78 nM and 83 nM for l-Tyr and d-Tyr (S/N = 3), respectively. It also exhibited the ability to determine the percentage of one Tyr enantiomer in the racemic mixture. Moreover, the selectivity, reproducibility, and stability of the chiral sensor were investigated to give satisfactory results. The above discoveries offered an alternative technology for chiral recognition with electrochemical response to actualize a real-time and quantitative determination.