1.3.3. Capillary electrophoresis and capillary electrochromatography of amino acids as dansyl derivatives

Abstract

Summary This chapter summarizes the advances in the enantioseparation of Dns-DL-AAs by CE and CEC. The basic principle of chiral recognition with the different chiral selectors is discussed by combining the typical examples for resolving the Dns-AAs. Cu(II) complexes with Lamino acids, L-amino acylamides or other complex-forming agents, CDs or CD derivatives, chiral surfactants and other chiral selectors have been well used as the chiral selectors added in the CE background electrolytes for chirally resolving Dns-DL-AAs. With the introduction of micellar phase of anionic surfactants in the CE electrolytes, two separation modes, LE-MEKC and CD-MEKC, have been developed for improving the separation selectivity. In addition, the combination of different chiral selectors, the addition of organic modifiers, and the adjustment of separation conditions like pH, ionic strength, buffer composition were also used to manipulate the selectivity. In CEC, with the advent of monolithic column technology, chiral stationary phases have been immobilized on the monolithic matrix by in situ co-polymerization and/or post-modifications or grafting of chiral selectors. Monolithic column technology makes CEC a very powerful technique for chiral separation with high separation selectivity and efficiency. New chiral selectors and column technology are expected to develop for the chiral separation of Dns-AAs in the future