Enantiometric separation of amino acids by copper (II)-L-arginine ligand exchange capillary zone electrophoresis.

A novel method for the separation of amino acid enantiomers by ligand exchange capillary zone electrophoresis (CZE) using a chiral Cu(II)-L-arginine ligand was developed in this paper. The effects of the buffer concentration, pH, the molar ratio of L-arginine to Cu(II), and the total concentrations of Cu(II) and L-arginine on the migration times and resolutions of chiral amino acids were investigated. The optimum experimental conditions were 40 mmol/L of NH4OAc, pH 7.0, the 2:1 concentration ratio of L-arginine to Cu(II), 1 mmol/L CuSO4 x 5H2O and 2 mmol/L L-arginine. Using the proposed method, six different dansyl-amino acids were separated successfully with the resolution ranging from 1.1 to 2.3 in less than 15 min.