Ligand exchange chiral separations by cyclodextrin derivatives in capillary electrophoresis.

A b-cyclodextrin substituted by an imidazole-bound histamine (CDmh) was successfully used to sep. underivatized tryptophan racemate in capillary electrophoresis in the presence of copper(II) ion by the ligand exchange mechanism. To the best of our knowledge, this is the first example of a cyclodextrin deriv. behaving as the first coordination sphere ligand in the complex added to the background electrolyte (BGE).