Enantiomeric separation of hydroxy acids and carboxylic acids by diamino-beta-cyclodextrins (AB, AC, AD) in capillary electrophoresis

Citation
G. Galaverna et al., Enantiomeric separation of hydroxy acids and carboxylic acids by diamino-beta-cyclodextrins (AB, AC, AD) in capillary electrophoresis, ELECTROPHOR, 22(15), 2001, pp. 3171-3177
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry & Analysis
Journal title
ELECTROPHORESIS
ISSN journal
0173-0835 → ACNP
Volume
22
Issue
15
Year of publication
2001
Pages
3171 - 3177
Database
ISI
SICI code
0173-0835(200109)22:15<3171:ESOHAA>2.0.ZU;2-H
Abstract
Selectively modified 6,6'-dideoxy-6,6'-L-diamino-beta -cyclodextrins (AB, A C, AD) were successfully used as chiral selectors for the enantiomeric sepa ration of hydroxy acids and carboxylic acids (in particular, phenoxyalkanoi c acid herbicides) in capillary electrophoresis (CE). Chiral separations we re obtained at a low selector concentration (1 mm) with good enantioselecti vity and resolution factors. Separations were optimized as a function of pH . The different position of the charged groups on the upper rim greatly inf luenced the separation, accounting for electrostatic interactions between t he protonated amino groups of the cycloclextrins (CDs) and the carboxylate of the selectands. The best enantiomeric separation of hydroxy acids was ob tained with the AC regioisomer, whereas carboxylic acids were well resolved only by the AB regioisomer. A recognition model is proposed, based on two- dimensional nuclear magnetic resonance (2-D NMR) experiments, in which the orientation of the guest in the inclusion complex is determined by the elec trostatic interactions between the selectand and the CD upper rim.