Most chiral compounds exhibit different biological and pharmacological activities because of their different effects between the enantiomers.Chiral separation of enantiomers has received great attention especially in production of pharmaceuticals and agriculture chemicals.Direct optical separation is a powerful method for enantiomer separations because of its inexpensive consumption and simple separation process.Several chiral selectors such as cyclodextrin,cellulose,and macrocyclic antibiotics have been widely used in chiral recognition [1].Teicoplanin is an important macrocyclic glycopeptide antibiotic and can be efficient employed for chiral separation because of its excellent structural characteristics.Recently,magnetic mesoporous nanoparticles have initiated intensive interest in many research fields due to their uniform nano-sizes,good magnetic responsibility,large surface areas,superior biocompatibility as well as ordered mesoporous structures [2].In this work,teicoplanin modified mesoporous silica magnetic nanoparticles (TE-MSMNPs) were fabricated as novel chiral magnetic nano-selectors.Several characterization techniques were used to confirm this successful preparation.The synthesized magnetic nanoparticles were regularly spherical (average diameter,600 nm),uniformly mesoporous (mean pore size,3.9 nm) and superior superparamagnetism (saturation magnetization,40 emu g-1).These functional magnetic nanoparticles were effectively used for direct optical separation of five racemic compounds in phosphate buffer.The results show that TE-MSMNPs possessed much stronger interaction with (+)-enantiomers than (-)-enantiomers.Capillary electrophoresis (CE) was employed for further investigating the chiral recognition abilities of TE-MSMNPs.After the racemic solution interacted with TE-MSMNPs,the supernatant was collected for CE analysis.The decrement of the peak areas in (+)-enantiomer was much more than that in (-)-enantiomer,suggesting that TE-MSMNPs was discriminatorily interacted with both of the two enantiomers and showed stronger interaction with the (+)-enantiomer than that with the (–)-enantiomer in the chiral separation.After washed with water and ethanol by sonication,these magnetic nanoparticles could be recycled at least three times with little loss of activity and be easily separated from the racemic solutions under an external magnetic field.These magnetic nano-materials are suitable for enantiomer separations.