Separation of enantiomers by capillary electrochromatography

The current popularity of capillary electrochromatography (CEC) has led to an increasing number of studies on the development and evaluation of enantioselective CEC systems. These studies clearly demonstrate that the most prominent advantage of electrically driven separation methods, the vastly increased column efficiency as compared to pressure-driven chromatography, can also be experimentally achieved for the separations of enantiomers. In analogy to high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE), several approaches have been used. The addition of a chiral selector to the mobile phase is the simplest method. Less erroneous and more elegant approaches are those that use open-tubular, conventional packed, and monolithic columns containing chiral stationary phases that stereoselectively interact with enantiomers. This review evaluates the new techniques and compares them to enantioselective HPLC and CE. Further, it describes the various concepts of enantioselective CEC and focuses on the current ‘state-of-the-art' column technology.