Nonaqueous capillary electrophoretic separation of enantiomers using the single-isomer heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin as chiral resolving agent

Abstract

The sodium salt of the single isomer heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin has been used as chiral resolving agent for the nonaqueous capillary electrophoretic separation of the enantiomers of a variety of weak base pharmaceuticals in 100% methanol background electrolytes. As predicted by the charged resolving agent migration model of enantiomer separations, very large separation selectivities were observed for the cationic analytes around the heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin concentrations where the effective mobilities of the slower migrating enantiomers approached zero. Neutral analytes and acidic analytes complexed very weakly with heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin in the methanolic background electrolytes. Heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin proved to be a useful chiral resolving agent in 100% methanolic background electrolytes for a variety of weak base analytes that have limited solubilities in aqueous background electrolytes.