CAPILLARY-ELECTROPHORESIS, NUCLEAR-MAGNETIC-RESONANCE AND MASS-SPECTROMETRY STUDIES OF OPPOSITE CHIRAL RECOGNITION OF CHLORPHENIRAMINE ENANTIOMERS WITH VARIOUS CYCLODEXTRINS

Markedly different chiral separation abilities were observed for nativ e beta-cyclodextrin (beta-CD), carboxymethyl-beta-CD (CM-beta-CD) and heptakis (2,3,6-tri-O-methyl)-beta-CD (TM-beta-CD) towards the enantio mers of (+/-)-chlorpheniramine ((+/-)-CHL) in capillary electrophoresi s (CE). Native beta-CD afforded almost baseline enantioseparation at a concentration of 18 mg/mL, whereas only 1 mg/mL solution of CM-beta-C D was required for adequate enantioseparation. TM-beta-CD allowed the nearly baseline enantioseparation only at a concentration as high as 8 0 mg/mL. Moreover, the migration order of (+/-)-CHL in the presence of TM-beta-CD was opposite to that with beta-CD and CM-beta-CD. H-1 and C-13-NMR spectroscopy and electrospray ionization mass spectrometry (E SI-MS) have been used in order to obtain preliminary information about the stoichiometry and the binding constants in the intermolecular dia stereomeric complexes of (+/-)-CHL with these CDs.