A Family of Single-Isomer Chiral Resolving Agents for Capillary Electrophoresis. 1. Heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin

A new, moderately hydrophobic, single-isomer charged cyclodextrin, the sodium salt of heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin, has been synthesized and used to separate a variety of neutral, weak acid, strong base, weak base, and zwitterionic racemic enantiomers in low-pH and high-pH background electrolytes. Separation selectivity for the netural analytes rapidly decreases as the concentration of heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin increases. For charged analytes, selectivity can increase, decrease, or pass a maximum, depending on the numeric values of the respective complexation constants and ionic mobilities. In addition to separation selectivity, the extent of peak resolution that can be realized strongly depends on the magnitude of the dimensionless electroosmotic flow. Heptakis(2,3-diacetyl-6-sulfato)-β-cyclodextrin proved to be a broadly applicable chiral resolving agent.