Determination of association constants of dansyl-amino acids and beta-cyclodextrin in N-methylformamide by capillary electrophoresis.
The use of nonaqueous background electrolytes in capillary electrophoresis (CE) is a promising new trend which should widen the scope of this technique. We demonstrate the chiral separation of dansyl-amino acids (Dns-AAs) in N-methylformamide (NMF) using beta-cyclodextrin (beta-CD) as chiral selector. The solubility of beta-CD is much better in NMF than in water, allowing high concentration of the chiral selector and successful enantioseparation despite the weak host-guest interaction between the Dns-AAs and beta-CD. The association constants for the complexation between Dns-AAs and beta-CD could be calculated from the electrophoretic mobilities, with attention paid to the change in viscosity of the electrolyte upon addition of beta-CD. The association constants ranged between 2 and 13 M(-1).
Valkó
I E
IE
University of Helsinki, Department of Chemistry, Finland. istvan.valko@helsinki.fi
Sirén
H
H
Riekkola
M L
ML
D000596:Amino Acids / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry*; D003619:Dansyl Compounds / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000379:methods*; D005559:Formamides / Q000737:chemistry*; D015394:Molecular Structure; D047392:beta-Cyclodextrins
D000596:Amino Acids; D003505:Cyclodextrins; D003619:Dansyl Compounds; D005559:Formamides; D047392:beta-Cyclodextrins; C031215:betadex; C002950:methylformamide