Synthesis, analytical characterization and use of octakis(2,3‐di‐<b><i>O</i></b>‐methyl‐6‐<b><i>O</i></b>‐sulfo)‐γ‐cyclodextrin, a novel, single‐isomer, chiral resolving agent in low‐pH background electrolytes

Abstract

The third member of the family of single-isomer, sulfated gamma-cyclodextrins, the sodium salt of octakis(2,3-di-O-methyl-6-O-sulfo)-gamma-cyclodextrin has been synthesized, analytically characterized and used for the capillary electrophoretic separation of the enantiomers of nonionic, weak acid and weak base analytes in low-pH aqueous background electrolytes. Though octakis(2,3-di-O-methyl-6-O-sulfo)-gamma-cyclodextrin complexes less strongly with many of the analytes tested than the other members of the single-isomer, 6-O-sulfo gamma-cyclodextrin family, such as octa(6-O-sulfo)-gamma-cyclodextrin and octakis(2,3-di-O-acetyl-6-O-sulfo)-gamma-cyclodextrin, it offers excellent separation selectivities, often complementary to those of both the single-isomer, 6-O-sulfo beta-cyclodextrins and 6-O-sulfo gamma-cyclodextrins. Rapid, efficient enantiomer separations were observed for a large number of structurally diverse analytes in acidic aqueous background electrolytes.