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Chiral separation of dansyl amino acids in capillary electrophoresis using mono‐(3‐methyl‐imidazolium)‐β‐cyclodextrin chloride as selector
Author(s) -
Tang Weihua,
Ong Teng Teng,
Ng SiuChoon
Publication year - 2007
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200600461
Subject(s) - chemistry , capillary electrophoresis , cyclodextrin , enantiomer , chromatography , amino acid , protonation , dansyl chloride , cationic polymerization , resolution (logic) , analyte , chiral resolution , carboxylate , organic chemistry , high performance liquid chromatography , derivatization , ion , biochemistry , artificial intelligence , computer science
Enantioseparations of fourteen dansyl amino acids were achieved by using a positively‐charged single‐isomer β‐cyclodextrin, mono‐(3‐methyl‐imidazolium)‐β‐cyclodextrin chloride, as a chiral selector. Separation parameters such as buffer pH, selector concentration, separation temperature, and organic modifier were investigated for the enantioseparation in order to achieve the maximum possible resolution. Chiral separation of dansyl amino acids was found to be highly dependent on pH since the degree of protonation of these amino acids can alter the strength of electrostatic interaction and/or inclusion complexation between each enantiomer and chiral selector. In general, the chiral resolution of dansyl amino acids was enhanced at higher pH, which indicates that the carboxylate group on the analytes may interact with the imidazolium group of cationic cyclodextrin. For most analytes, a distinct maximum in enantioresolution was obtained at pH 8.0. Moreover, the chiral separation can be further improved by careful tuning of the separation parameters such as higher selector concentration ( e. g . 10 mM), lower temperature, and addition of methanol. Enantioseparation of a standard mixture of these dansyl amino acids was further achieved in a single run within 30 min.