Enhancement of selectivity in capillary electrophoretic separations of metals and ligands through complex formation

A significant improvement of separation selectivity can be achieved in capillary electrophoresis by exploiting the formation of complexes which modify the analyte electrophoretic mobilities. Many organic compounds with electron-donor properties can form weak charge transfer complexes with suitable metals. These types of complexing equilibria can be exploited in the separation of both species involved in complex formation: metals and organic compounds. The first part of this article will review the use of complexation reactions to enhance separation selectivity in the analysis of metals whereas the second part will consider addition of metal ions to the background electrolyte to achieve separation of organic ligands. (C) 1998 Elsevier Science B.V.