Abstract
Earlier chromatographic data (Slama et al. Anal. Chem. 2002, 74, 5205) showed that the vancomycin dimerization was responsible for an enhancement of the dansyl valine enantioselectivity. In this paper, a new chromatographic system was used in order to investigate more easily the effects of the vancomycin dimerization on the solute chiral recognition. The retention and separation of D, L dansyl serine and D, L dansyl valine enantiomers were examined using an amino stationary phase and vancomycin as chiral mobile phase additive. A simplified interaction model was derived considering only the formation of vancomycin dimers in the mobile phase. This theoretical approach was convenient to describe, adequately, the retention behavior of the enantiomers. At an eluent pH of 5.5, it was shown that the glycopeptide dimerization increased the dansyl amino acid enantioselectivity by a factor around 1.50. This study demonstrated interest in using an amino stationary phase to study the glycopeptide dimerization dependence on the solute enantioselectivity.