Capillary GC using pyridyl beta-cyclodextrin stationary phase

A new beta-CD derivative, heptakis [2,6-di-O-pentyl-3-O-(4'-chloro-5'-pyridylmethyl)]-beta-CD, was synthesized by the selective introduction of a pyridyl group on the 3-positions of beta-CD. The chromatographic properties of the pyridyl beta-CD derivative were studied by using it as the stationary phase in capillary GC. The polarity of the prepared stationary phase was moderate, and the separation results demonstrated that the prepared stationary phase possessed excellent separation ability and chiral recognition for a wide range of analytes. Not only the aromatic positional isomers, such as o-, m-, p-xylene and alpha-, beta-naphthol isomers, but also some compounds with multi-stereogenic centers, such as n-(1-methylpropyl)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxamide and n-(1-methylpropyl)-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxamide with three stereogenic centers including eight configurational isomers, were successfully separated. The results also indicated that the polarity of the beta-CD derivative, and the hydrogen bonding between the beta-CD derivative, and the analytes had a very important effect on separation.