Abstract: A novel alcohol/salt-based aqueous two-phase system containing chiral selector hydroxypropyl-β-cyclodextrin(HP-β-CD) for enantioselective liquid-liquid extraction was introduced.The chiral recognition of α-cyclohexyl-mandelic acid(CHMA) enantiomers was studied in this system.The dependency of the distribution ratio (D) and the separation factors(α) on parameters such as the concentration of HP-β-CD,the concentration of CHMA, the mass fractions of C2H5OH and (NH4)2SO4,temperature and pH have been investigated.It was found that the C2H5OH-(NH4)2SO4-H2O aqueous two-phase system containing HP-β-CD as chiral selector showed a good chiral recognition ability toward CHMA enantiomers . It could be concluded that the enantioseparation strongly depended on the concentration of HP-β-CD,the mass fraction of C2H5OH,temperature and pH.The optimum conditions of enantioseparation were as follows:The temperature was 40 ℃,the pH was 2.0,the mass fraction of C2H5OH and (NH4)2SO4 was 30% and 15%, respectively,the concentration of HP-β-CD was 50 g.L-1,the concentration of CHMA was 0.5mmol.L-1.Under these conditions the separation factor(α) reached at 1.86.

Key words: Keywords Aqueous two-phase system, Chiral recognition, α-cyclohexyl-mandelic acid enantiomers；Hydroxypropyl-β-Cyclodextrin