Dual chiral selectors modified magnetic particles for enantioseparation of tryptophan and mandelic acid enantiomers in aqueous medium

The realization of complete enantioseparation of a racemate in a single step is still a difficulty to be addressed. In this work, L-tryptophan (Trp) imprinted chitosan modified magnetic particles (Fe3O4@CS@MIP) were fabricated in a three-step process. The particles were spherical with an average diameter of 208.6 +/- 9.6 nm. The thicknesses of CS and MIP layers were 3.9 +/- 0.9 and 2.5 +/- 1.4 nm, respectively. Fe3O4@CS@MIP possessed the chiral selectivity of CS and the stereoselective cavities of MIP. They were able to achieve the complete chiral separation of Trp racemate in aqueous solutions in a single step. The enantiomeric excess (ee) was almost 100%. The imprinting factor of this material for L-Trp was 5.75. Furthermore, Fe3O4@CS@MIP prepared using S-mandelic acid (S-MA) as a template also exhibited enantioselectivity toward S-MA with an ee value of 30%. The results demonstrate that the strategy for the preparation of chiral adsorbents has great potential in enantioseparation.

Automated summary

The study successfully fabricated L-tryptophan imprinted chitosan modified magnetic particles in a three-step process, achieving complete enantioseparation of chiral mixtures with high enantiomeric excess. The results highlight the great potential of the strategy for preparing chiral adsorbents in enantioseparation.