A family of single‐isomer positively charged cyclodextrins as chiral selectors for capillary electrophoresis: Mono‐6 A ‐butylammonium‐6 A ‐deoxy‐β‐cyclodextrin tosylate

• Published in: Electrophoresis Vol. 26; no. 16; pp. 3125 - 3133
• Main Authors: Tang, Weihua, Muderawan, I Wayan, Ong, Teng Teng, Ng, Siu‐Choon
• Format: Journal Article
• Language: English
• Published: 01.08.2005
• ISSN: 0173-0835; 1522-2683
• DOI: 10.1002/elps.200500018

Abstract A novel single‐isomer positively charged β‐cyclodextrin (β‐CD), mono‐6 A ‐butylammonium‐6 A ‐deoxy‐β‐cyclodextrin tosylate (BuAM‐β‐CD), has been synthesized, characterized, and used for the enantioseparations of α‐hydroxy acids, carboxylic acids, and ampholytic analytes by capillary electrophoresis in acidic aqueous background electrolytes. The effective mobilities of all studied analytes decreased with increasing concentration of CD. Satisfactory resolutions were obtained for α‐hydroxy acids over a wide range of chiral selector concentration. The optimum CD concentration was lower than 5 m M for the carboxylic acids, while higher than 20 m M for α‐hydroxy acids. Inclusion complexation in combination with ion pair interaction seemed to account for the chiral discrimination process. The hydrogen bonding may provide secondary contribution for the chiral resolution of α‐hydroxy acids. In addition, BuAM‐β‐CD was further proved to be an effective chiral selector for anionic analytes by the baseline enantioseparation of a six‐acid mixture within 20 min.