Utilization of n-alkyl-beta-D-glucopyranosides in enantiomeric separation by micellar electrokinetic chromatography

The n-octyl-beta-D-glucopyranoside has been previously used in micellar liquid chromatography to separate racemic mixtures. We report here on the utilization of n-alkyl-beta-D-glucopyranosides (from C-7 to C-10) as pseudo stationary phases in the separation by HPCE of racemic mixtures of amino acids, derivatized as carbamates. The result from this comparative study was that the best enantiomeric selectivity is obtained with the n-nonyl-beta-D-glucopyranoside. Using this chiral surfactant we optimized different operating parameters such as: concentration of surfactant, ionic strength and pH of the mobile phase and temperature. Therefore it appeared that this new electrophoretic system is performing best at 18 degrees C, with an 80 mM concentration of surfactant in the electrolyte constituted by a NaHCO3-NaOH buffer, the applied voltage being equal to 15 kV. The enantiomeric selectivity of this system, original because of the nature of the micellar additive (neutral micelle), seems to be a function of the analyte hydrophobicity.