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

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 (I D-Tyr  > I L-Tyr ; I D-Trp  < I L-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.