Use of a zwitterionic cyclodextrin as a chiral agent for the separation of enantiomers by capillary electrophoresis.
The purity and enantioselectivity of a novel chiral agent, the zwitterionic mono-(6-delta-glutamylamino-6-deoxy)-beta-cyclodextrin (beta-CD-Glu), were studied by capillary electrophoresis. Chiral separation of the enantiomers of chlorthalidone was obtained at pH 2.3, a pH at which beta-CD-Glu is partially protonated. Comparison with the cationic mono-(6-amino-6-deoxy)-beta-cyclodextrin (beta-CD-NH2) enantioselectivity clearly shows that the greater the difference in mobility between the free analyte and the analyte-cyclodextrin complex, the better the resolution. Hydrobenzoin enantiomers were separated at pH 11.2, a pH at which beta-CD-Glu is anionic. Under these conditions, the migration order was opposite to that observed in the presence of beta-CD-NH2 at pH 2.3. When no separation was obtained directly with beta-CD-Glu, a dual cyclodextrin system was developed. Carprofen enantiomers were resolved at pH 2.3 in the presence of a beta-CD-Glu/trimethyl-beta-cyclodextrin (TM-beta-CD) system in which the charged CD confers a non-zero mobility to the analyte, while the neutral CD allows chiral recognition.
Lelièvre
F
F
Laboratoire d'Electrochimie et de Chimie Analytique (URA CNRS 216), Ecole Nationale Supérieure de Chimie de Paris, France.
Gueit
C
C
Gareil
P
P
Bahaddi
Y
Y
Galons
H
H
D003505:Cyclodextrins / Q000737:chemistry* / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure
D003505:Cyclodextrins