Recent innovation in capillary electrokinetic chromatography with replaceable charged pseudostationary phases or additives

Recent developments of separation of neutral analytes in capillary systems with the mobile phase driven by the electroosmotic flow (EOF) and charged a dditives acting as a pseudostationary phase are reviewed. As pseudostationa ry phases a number of additives are used. Soluble polymers, either anionic or cationic, were applied as alternatives to micelles. Monomeric charged ad ditives are also intended to form associates with the analytes, leading to selective retention and separation in a similar way as the polymeric pseudo stationary phases. Dendrimers, spherical macromolecules with highly branche d chains and charged terminal groups, are successfully applied for the sepa ration of lipophilic analytes. Polymers with covalently stabilized structur es are introduced in the form of permanent micelles and are therefore insen sitive to the mobile phase composition, enlarging the applicability of mice llar electrokinetic capillary chromatography (MEKC).