Separation of amino acid enantiomers by micellar electrokinetic capillary chromatography using synthetic chiral surfactants.

A synthetic chiral surfactant was employed for the enantioselective micellar electrokinetic capillary chromatographic (MECC) separation of amino acid enantiomers derivatized with 6-aminoquinoyl-N-hydroxysuccinimidyl carbamate (AQC). The effect of surfactant concentration and buffer pH on resolution was studied, and the optimized conditions were used to evaluate the method in terms of sensitivity, reproducibility, and linearity. Resolution and alpha values for 12 ACQ-derivatized amino acids are reported. The ability to perform both achiral and chiral separations simultaneously is illustrated in a separation of a mixture of six amino acid enantiomeric pairs, all with baseline resolution. The direct reversal of enantiomer migration order, useful in quantitation and chiral identification, is also shown. Comparisons with other N-protected amino acid derivatives are made in terms of resolution and sensitivity, and the advantages of this chiral MECC technique used in conjunction with the inherent advantages of the AQC derivatizing reagent are discussed.