Chiral separation of dansyl-amino acids in a nonaqueous medium by capillary electrophoresis

In this study the feasibility of using pure organic solvents as separation media in capillary electrophoresis was tested. The chiral separation of individual dansyl-amino acids was compared in aqueous phosphate-borate buffer and in N-methylformamide. In both cases beta-cyclodextrin was used as a chiral selector. The low solubility of beta-cyclodextrin in water may have hindered the separation of some dansyl-amino acid enantiomers when the aqueous buffer was used. By contrast, N-methylformamide proved to be an excellent solvent for beta-cyclodextrin. The chiral separation of ten dansyl-amino acids is demonstrated for beta-cyclodextrin in N-methylformamide. The results indicate the potential of organic solvents for chiral separations by capillary electrophoresis.