Recent developments in chiral separations by supercritical fluid chromatography

The increasing interest for obtaining pure, single enantiomers of chiral organic compounds has greatly expanded the progress of new synthetic procedures, especially in the field of chiral drugs, agrochemicals, flavors, and natural products. A parallel trend has been observed in the development of stereoselective separation methods for the precise and accurate measurements of the enantiomeric purity of chiral compounds. The advent of chiral stationary phases for gas or liquid chromatographic applications in the last three decades changed the approach to determine enantiomeric purity on the analytical scale and to obtain sizeable amounts of pure enantiomers by preparative resolutions. In recent years, continuous efforts have been placed on faster analytical methods and on environment-friendly processes. Chromatographic processes using supercritical fluids, especially carbon dioxide, combine both aspects with success because of the extremely favorable properties of the eluents in terms of physicochemical parameters and of impact on the environment. An overview of the recent achievements in the field of supercritical fluid chromatography using packed column with chiral stationary phases will be given, with an emphasis on very recent studies on high-efficiency, ultrafast chiral separations.