Separation Science and Technology, Vol.53, No.18, 2981-2989, 2018
Preparative enantioseparation of 2-(4-hydroxyphenyl)propionic acid by high speed counter-current chromatography with hydroxyethyl-beta-cyclodextrin as chiral selector
Enantiomers of 2-(4-hydroxyphenyl)propionic acid (HPPA) were successfully separated by high-speed counter-current chromatography (HSCCC) using hydroxyethyl-beta-cyclodextrin (HE-beta-CD) as chiral selector. Liquid-liquid extraction was applied to optimization of the two-phase solvent system used in HSCCC separation. A two-phase solvent system composed of isobutyl acetate and 0.1 mol L-1 phosphate buffer solution containing HE-beta-CD (1:1, v/v) was selected. Factors affecting the distribution behavior of HPPA in the two-phase solvent system were studied separately, including pH of aqueous solution, concentration of HE-beta-CD and equilibrium temperature. The optimum conditions containing pH of 2.50, 0.1 mol L-1 of HE-beta-CD concentration, 5 degrees C of temperature were obtained. Under the optimum conditions, 20 mg of HPPA enantiomers could be completely separated by HSCCC in a head-to-tail mode. Purities of the separated enantiomers were over 99.5% as determined by HPLC.
Keywords:High-speed countercurrent chromatography;enantioseparation;2-(4-hydroxyphenyl)propionic acid;hydroxyethyl-beta-cyclodextrin;liquid-liquid extraction