Chiral stationary phase
Chiral column chromatography is a variant of column chromatography in which the stationary phase contains a single enantiomer of a chiral compound rather than being achiral. The two enantiomers of the same analyte compound differ in affinity to the single-enantiomer stationary phase and therefore they exit the column at different times.
The chiral stationary phase can be prepared by attaching a suitable chiral compound to the surface of an achiral support such as silica gel, which creates a Chiral Stationary Phase (CSP). Many common chiral stationary phases are based on oligosaccharides such as cellulose or cyclodextrin (in particular with β-cyclodextrin, a seven sugar ring molecule). As with all chromatographic methods, various stationary phases are particularly suited to specific types of analytes.
Chiral Stationary Phases are much more expensive than comparable achiral stationary phases such as C18.
The principle can be also applied to the fabrication of monolithic HPLC columns or gas chromatography columns.
...
Wikipedia