title: Chiral separation of highly negatively charged enantiomers by capillary electrophoresis.
abstract: The separation of two highly negatively charged enantiomeric organic disulfates containing two chiral centers was investigated by capillary electrophoresis using cyclodextrin based chiral selectors added to the run buffer. The optimum separation for the enantiomers was achieved in less than 3 min at 25 degrees C with a run buffer of 10 mM glycine pH 2.4 and 5 mM QA-beta-CD, which is a positively charged quaternary ammonium beta-cyclodextrin derivative. The method resulted in baseline resolution, excellent linearity, and highly reproducible migration times allowing facile evaluation of the enantiomeric purity of the individual isomers. Detection limits for the enantiomeric pair were determined to be 0.3 ng/microl (S/N = 3). The nature of the selector-enantiomer interaction and a quantitative measurement of the apparent stability constants that governed chiral discrimination of the enantiomers with QA-beta-CD were also investigated by UV-Vis spectroscopy and electrospray ionization mass spectrometry.
authors.affiliation: Department of Chemistry, College ofArts and Sciences, University of Toledo, Toledo, OH 43606, USA.
authors.forename: Qinfeng
authors.initials: Q
authors.lastname: Liu
authors.forename: Takayo
authors.initials: T
authors.lastname: Inoue
authors.forename: Jon R
authors.initials: JR
authors.lastname: Kirchhoff
authors.forename: Chunli
authors.initials: C
authors.lastname: Huang
authors.forename: L M V
authors.initials: LM
authors.lastname: Tillekeratne
authors.forename: Kay
authors.initials: K
authors.lastname: Olmstead
authors.forename: R A
authors.initials: RA
authors.lastname: Hudson
mesh_terms: D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism