Stationary Phases for Chiral Chromatography

With chiral affinity phases, proteins undergo enantioselective interactions with a great variety of drugs. Thus, the resolution on chiral affinity stationary phases is due to interactions of the enantiomers with proteins bonded to the solid support. Typical proteins used for chiral affinity separa- 

Principle Chiral selector (example) Ref. Mobile phase Substrate (example) 

Inclusion T riacety lcellulose 78 Organic Aromatic compounds 

Multiple H-bond Polymethacrylate 83 Organic Aromatic compounds 

77-donor/acceptor phases (R)-N-( 3,5- Dinitrobenzoyl)phenyl- glycine 84 Organic Amides, cyclic imides, carbamates 

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If absorptions are limited to the UV range, interferences can become a considerable problem. The lack of selectivity of the Cy was also mentioned before. Future choices for chiral hosts will be based upon different association mechanisms and presumably will emphasize greater potential for selectivity. Virtually any material that has seen use as a stationary phase for chiral chromatography is a candidate, and others will eventually appear. Some of these have in fact been employed already, although not to the same degree that the Cy have, (e.g. cryptands, vesicles, micelles, metal complexes, and proteins). Their immediate most obvious advantage is a substantial increase in the magnitude of the induced ellipticity, which can be enhanced even further by fluorescence detection. 

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