Interphase model for retention and selectivity in micellar electrokinetic chromatography

The fundamental properties of micelles are reviewed to arrive at a working definition of a micellar solvent for micellar electrokinetic chromatography (MEKC). Emphasis is placed on the dynamic nature of micelles, the influence of the external electrolyte environment on micelle properties, and factors that influence solubility of neutral solutes in micelles. The solvation parameter model is used to characterize the capacity of common surfactants for defined intermolecular interactions as a basis for understanding selectivity in MEKC. The need for additional surfactants and their required solvation properties to provide a wider selectivity range for methods development is identified. As an approach to understanding the mechanism of retention in MEKC an interphase model is proposed.