Enantiomer separations by capillary electrochromatography using chiral stationary phases

The applicability of capillary electrochromatography (CEC) using packed capillary column to enantiomer separations was investigated. As chiral stationary phases, OD type packing materials of 5 and 3 μm particle diameters, originally designed for conventional high-performance liquid chromatography (HPLC) were employed. The chiral packing materials were packed by a pressurized method into a 100 μm I.D. fused-silica capillary. Several racemic enantiomers, such as acidic, neutral and basic drug components, were successfully resolved, typically by using acidic or basic solutions containing acetonitrile as mobile phases. The separation efficiencies for some enantiomers in the chiral CEC system using the 5 μm OD type packing were superior to those obtained in HPLC using chiral packings. The plate heights obtained for several enantiomers were 8–13 μm or the reduced plate height of 1.6–2.6, which indicates the high efficiency of this chiral CEC system.