Considerations on the Enantiomeric Separation by MEKC of N-Bz-Amino Acids with N-Dodecoxycarbonylvaline as Chiral Selector

Abstract

N-dodecoxycarbonyl-(S)-valine was evaluated for the separation of some benzoylated amino acids (alanine, aminobutyric acid and leucine). Successful enantiomeric separation required blocking of the carboxylic function by the formation of the methyl esters in order to avoid repulsion of the charged carboxylate group by the hydrophobic interior of the chiral micelles. A model of chiral recognition is presented. The highest enantioselectivity was obtained for the 3,5-dinitrobenzoyl derivatives (α > 1.07). Based on the data, the generally accepted MEKC-resolution equation was experimentally verified and confirmed.