Evaluation of cyclodextrin-micellar electrokinetic capillary chromatography with pyrrolidinium-based ionic liquid surfactant as a pseudostationary phase for chiral separation

Ionic liquids have drawn increasing attention in separation science recently. As a new promising brand of surfactants, ionic-liquid-based surfactants have their unique properties and superior aggregation behavior, which can be introduced as micelle-forming surfactants in micellar electrokinetic capillary chromatography mode. There have been few reports of the applications of ionic-liquid-based surfactants for micellar electrokinetic capillary chromatography enantioseparation. In this study, pyrrolidinium-based ionic liquids surfactants were applied for the first time for chiral separation with hydroxypropyl-beta-cyclodextrin as a chiral selector by micellar electrokinetic capillary chromatography. As observed, the established micellar electrokinetic capillary chromatography systems with ionic-liquid-based surfactants could provide better separation of tested chiral drugs than conventional non-ionic liquid cationic surfactant. In addition, parameters such as the alkyl chain length, concentration of ionic-liquid-based surfactants, type and proportion of organic modifier, concentration of chiral selector and composition and pH of buffer solution were systematically investigated to optimize the cyclodextrin-micellar electrokinetic capillary chromatography system.