Synthesis of a chiral ionic liquid, cholinium-clindamycin phosphate, as sole chiral selector in capillary electrophoresis

Abstract

Recently, in separation science, ionic liquids (ILs) have been commonly used as modifiers for buffer solutions, dynamic coating solutions, or coating solutions on carriers in capillary electrophoresis. However, only several papers have reported the use of chiral ILs as the sole chiral selector. In this paper, a chiral ionic liquid, cholinium-clindamycin phosphate (Ch-CP), was synthesized and employed as a sole chiral selector in capillary electrophoresis (CE). A series of parameters affecting the separation were optimized, including chiral selector concentration, buffer pH, proportion of organic modifier, as well as the applied voltage. Under the optimal conditions, compared to clindamycin phosphate (CP), the IL selector showed better enantioseparation capability and improved peak shapes for five racemic drugs. In addition, Molecular docking program Autodock was employed to elucidate the chiral recognition mechanism of Ch-CP, the computing results conformed to the experimental results.