Optical resolution by high-performance capillary electrophoresis : micellar electrokinetic chromatography with sodium N-dodecanoyl-L-glutamate and digitonin

Abstract Optical resolution by micellar electrokinetic chromatography with sodium N-dodecanoyl- l -glutamate (SDGlu) and with digitonin— sodium taurodeoxycholate (STDC) mixed micelles was investigated. Addition of sodium dodecyl sulphate, urea and methanol to SDGlu micellar solutions could give improved peak shapes and resolution. With SDGlu, phenylthiohydantoin (PTH) derivatives of five dl -amino acids (α-aminobutyric acid, methionine, norvaline, tryptophan and norleucine) were separated from each other and each pair of enantiomers was optically resolved. On the other hand, three PTH- dl -amino acids (norvaline, valine and α-aminobutyric acid) were also successfully resolved with a digitonin-STDC-urea solution (pH 2.5).