A FAMILY OF SINGLE-ISOMER CHIRAL RESOLVING AGENTS FOR CAPILLARY ELECTROPHORESIS .2. HEPTA-6-SULFATO-BETA-CYCLODEXTRIN

A new, hydrophilic, single-isomer charged cyclodextrin, the sodium sal t of hepta-6-sulfato-beta-cyclodextrin has been synthesized, character ized, and used for the capillary electrophoretic separation of the ena ntiomers of numerous noncharged, acidic, basic, and zwitterionic analy tes, Hepta-6-sulfato-beta-cyclodextrin proved to be a much stronger co mplexing agent for all the analytes tested, in both low-pH and high-pH background electrolytes, than the previously synthesized, moderately hydrophobic ptakis-(2,3-diacetyl-6-sulfato)-beta-cyclodextrin. The sep aration selectivities of the two single-isomer, differently functional ized charged cyclodextrins often proved to be complementary, In agreem ent with the predictions of the charged resolving agent migration mode l, separation selectivity for the noncharged analytes decreased as the concentration of hepta-6-sulfato-beta-cyclodextrin was increased. For acidic, basic, and zwitterionic analytes, selectivity could increase, decrease, or pass a maximum, depending on the binding strength of the enantiomers and ionic mobilities of both the complexed and noncomplex ed forms of the enantiomers.