Electrophoresis, Vol.23, No.17, 3027-3034, 2002
Comparative enantioseparations with native beta-cyclodextrin and heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin in capillary electrophoresis
Twenty-three cationic chiral analytes were resolved in capillary electrophoresis using native beta-cyclodextrin and single isomer heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cycloclextrin as chiral selectors. For 12 of 16 chiral analytes resolved with both chiral selectors the enantiomer migration order was opposite. In selected cases the structure of cyclodextrin-analyte complexes in aqueous solution was investigated using one-dimensional transverse rotating frame nuclear Overhauser and exchange spectroscopy. It was found that in contrast to mainly inclusion-type complexes between chiral analytes and beta-cyclodextrin, external complexes are formed between the chiral analytes and structurally crowded, highly charged heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin.
Keywords:beta-cyclodextrin;capillary electrophoresis;chiral recognition;enantioseparation;Heptakis-(2-0-methyl-3,6-di-O-sulfo)-o-cyclodextrin One-dimensional transverse rotating;frame nuclear Overhauser and exchange spectroscopy