Synthesis of charged cyclodextrin highly soluble in organic solvents for enantiomer separations in capillary electrophoresis

Abstract

Synthesis of charged cyclodextrin highly soluble in organic solvents was made by exchanging the inorganic counter ion (Na+) of heptakis (2,3-di-Omethyl- 6-O-sulfo)-β-CD (Na7HDMS) with tetrabutylammonium (TBA+), to produce TBA7HDMS. The same ion exchange was used to synthesize the TBA salts of the analogous CDs TBA6HxDMS and TBA8ODMS. Indirect-UV detection capillary electrophoresis (CE) and 1H NMR were used as the characterization methods. Separations of thirteen pharmaceuticals were made using TBA7HDMS as the chiral resolving agent in aqueous CE. On the other hand, a set of twenty pharmaceuticals was used for the enantiomer separations in non-aqueous CE (NACE). Comparison between the results obtained with TBA7HDMS in aqueous and non-aqueous CE were made. In addition, comparison between the results obtained with TBA7HDMS and Na7HDMS in aqueous and non-aqueous CE were made as well.