Manipulation of separation selectivity in capillary zone electrophoresis of anionic solutes

This article discusses the main approaches to the manipulation of the separ ation selectivity of inorganic and low-molecular-mass anions in capillary z one electrophoresis (CZE). Physical or instrumental effects such as the det ection mode, the sampling mode, the separation voltage, and the temperature are easy to control but their influence on selectivity is generally minima l, except for the use of selective detection. Selectivity effects arising f rom chemical parameters (i.e. effective size and charge, and structure of a nalyte; the pH, surfactant type and content, polyelectrolyte content, organ ic solvent content of the electrolyte; capillary treatment; and complexing agents) are much more significant than those resulting from physical effect s. The effects on separation selectivity exerted by some of the above param eters can be complex, so that manipulation of selectivity in CZE of anionic solutes is often difficult. Nonetheless, many practical applications can b e performed through the judicious control of parameters noted in this revie w. Some practical limitations to selectivity manipulation are highlighted a nd possible areas that can be studied in the future for selectivity control are noted. (C) 2001 Elsevier Science B.V. All rights reserved.