Electrochemical chiral recognition of tryptophan enantiomers by using chiral polyaniline and β-CD-MOF

Abstract

Chiral detection of tryptophan (Trp) isomers is of vital importance and the introduction of efficient, stable and sensitive enantioselective recognition technology is in high demand in the fields of medicine, food and life science. Herein, a facile and sensitive electrochemical probe for the chiral recognition of Trp enantiomers by using chiral polyaniline (D-PANI) and β-CD-MOF is presented. The structure and electrochemical performance of the designed sensor (GCE/β-CD-MOF/D-PANI) were characterized via FT-IR, SEM, TEM, EIS, CV and DPV methods. Under the optimized conditions, the enantiomer selection coefficient (I_L/I_D) reached 2.26, and the detection limits for L- and D-Trp were calculated to be 6.67 and 16.1 μM, respectively. The higher DPV result for L-Trp was attributed to its higher affinity for the chiral selectors D-PANI and β-CD-MOF than that of D-Trp. Moreover, the proposed chiral sensing platform could be used for analyzing the percentage of D-Trp in enantiomer mixed solutions and human urine samples with satisfactory recoveries.