Capillary electrophoretic resolution of chiral aryl alkyl and aryl benzyl sulphoxides using sulphated beta-cyclodextrins as chiral selectors

The enantiomeric resolution of a series of chiral aryl alkyl and aryl benzy l sulphoxides was investigated by reversed-polarity capillary electrophores is using sulphated-beta -cyclodextrins as chiral selectors. Separations wer e performed using fused silica capillaries with a lithium phosphate run buf fer (100 mM, pH 2) containing hydroxyethylcellulose as a dynamic coating ag ent to virtually eliminate electroosmotic flow and sulphated-Beta-cyclodext rins as chiral selectors. The majority of enantiomeric pairs were resolved in the presence of heptakis-6-sulphato-beta -cyclodextrin, heptakis-(2,3-di acetyl-6-sulphato)-beta -cyclodextrin, and sulphated-beta -cyclodextrin (av erage degree of substitution = 4). In general, the electrophoretic migratio n order was R- before S-sulphoxide, indicating generally greater affinities between the R-enantiomers and the sulphated beta -CDs.