Chiral capillary electrophoresis with cationic pyrrolidinium-beta-cyclodextrin derivatives as chiral selectors.
New single-isomer, cationic beta-cyclodextrins, including mono-6-deoxy-6-pyrrolidine-beta-cyclodextrin chloride (pyCDCl), mono-6-deoxy-6-(N-methyl-pyrrolidine)-beta-cyclodextrin chloride (N-CH(3)-pyCDCl), mono-6-deoxy-6-(N-(2-hydroxyethyl)-pyrrolidine)-beta-cyclodextrin chloride (N-EtOH-pyCDCl), mono-6-deoxy-6-(2-hydroxymethyl-pyrrolidine)-beta-cyclodextrin chloride (2-MeOH-pyCDCl) were synthesized and used as chiral selectors in capillary electrophoresis for the enantioseparation of carboxylic and hydroxycarboxylic acids and dansyl amino acids. The unsubstituted pyCDCl exhibited the greatest resolving ability. Most analytes were resolved over a wide range of pH from 6.0 to 9.0 with this chiral selector. In general, increasing pH led to a decrease in resolution. The effective mobilities of all the analytes were found to decrease with increasing CD concentration. The optimal concentration for most carboxylic acids and dansyl amino acid was in the range 5-7.5 mM and >15 mM for hydroxycarboxylic acids. (1)H NMR experiments provided direct evidence of inclusion in the CD cavity.
Xiao
Yin
Y
School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.
Wang
Yong
Y
Ong
Teng-Teng
TT
Ge
Liya
L
Tan
Swee Ngin
SN
Young
David J
DJ
Tan
T T Y
TT
Ng
Siu-Choon
SC
D002412:Cations; D002853:Chromatography, Liquid; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D011759:Pyrrolidines / Q000737:chemistry*; D013237:Stereoisomerism; D047392:beta-Cyclodextrins / Q000737:chemistry*
D002412:Cations; D011759:Pyrrolidines; D047392:beta-Cyclodextrins; C031215:betadex