It involves the separation of stereoisomers into enantiomers. The stationary phase is chiral instead of achiral. The enantiomers of the same compound then differ in affinity to the stationary phase, thus they would have different retention time. Many of the columns are available for either HPLC or SFC applications.
RStech ChiroSil
ChiroSil columns are excellent for enantiomer separation of natural/synthetic alpha-amino acids, alpha-amino acid derivatives, and primary amines. Other racemic compounds known to be separated on ChiroSil columns include amino alcohols (beta-blockers), secondary amines, and compounds containing both primary and secondary amines. The chiral stationary phase for ChiroSil RCA(+) and SCA(-) is prepared by a covalent trifunctional bonding of (+) or (-)-(18-Crown-6)-tetracarboxylic acid as the chiral selector to aminopropyl silica gel.
Orochem
Orochem Epitomize CSP1 Chiral columns are based on cellulose tris (3,5-dimethyl phenyl carbamate) coated on spherical silica. They are excellent for separating these racemic compounds, e.g., atropine, proglumide, flavanone, homatropine...etc.
Orochem Epitomize CSP-2 series, shown in the table below, is based on derivatized polysaccharides that are covalently-bound to silica gel. The covalent linkage permits the use of all typical organic solvents including ketones (e.g., acetone), halogenated solvents (e.g., dichloromethane and chloroform), ethyl acetate, THF, MTBE, and other aggressive solvents such as DMF and DMA. The CSP-2 series allows the separation of many new racemates that could not be accomplished on coated CSPs due to mobile phase limitations. The CSP-2-R series is available for aqueous-based mobile phases.