Enantioselective separation of <i>RS</i>-mandelic acid using β-cyclodextrin modified Fe₃O₄@SiO₂/Au microspheres

Abstract

Chiral magnetic microspheres show great potential in direct enantioseparation. Herein novel chiral magnetic microspheres were prepared by self-assembling β-cyclodextrin on magnetic Fe3O4@SiO2/Au composite microspheres. The prepared materials were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the functional microspheres have a three-ply structure and high saturation magnetization. β-Cyclodextrin-immobilized magnetic Fe3O4@SiO2/Au microspheres (Fe3O4@SiO2/Au/β-CD) were applied in the direct chiral separation of RS-mandelic acid. The analysis results of HPLC revealed that the Fe3O4@SiO2/Au/β-CD magnetic microspheres exhibited stronger enantioselective adsorption for R-mandelic acid than S-mandelic acid. The chiral selector functionalized magnetic microspheres are therefore expected to be an efficient and economical chiral separation method for use in further research.