A chiral sensing platform based on chiral metal-organic framework for enantiodiscrimination of the isomers of tyrosine and tryptophan

Abstract

Chiral metal–organic framework (ZIF-8) was successfully prepared through a two-step electrodepostion method by using l-histidine (l-His) as the chiral source, and the resultant chiral ZIF-8 (l-His-ZIF-8) was used for enantiodiscrimination of the isomers of tyrosine (Tyr) and tryptophan (Trp). Although the isomers of both Tyr and Trp could be well discriminated by the l-His-ZIF-8 modified electrode, they displayed opposite voltammetric behaviors on the differential pulse voltammograms (ID-Tyr > IL-Tyr; ID-Trp < IL-Trp), which could be explained by density functional theory (DFT). Finally, both the pH and the electrodeposition time were optimized to obtain the highest recognition efficiency of the l-His-ZIF-8 modified electrode toward the isomers of Tyr and Trp.