MIGRATION BEHAVIOR OF MICELLE COUNTERIONS IN MICELLAR ELECTROKINETIC CHROMATOGRAPHY - INFLUENCE ON MICELLE MOBILITY, EFFICIENCY AND SELECTIVITY

The migration behaviour of micelle counterions in micellar electrokine tic chromatography (MEKC) is treated theoretically. It is demonstrated that, due to a high degree of counterion binding, micelle counterions in commonly used surfactant systems possess negative transport number s under MEKC conditions. This phenomenon is illustrated for a sodium d odecyl sulphate micellar system in which sodium ions possess a negativ e effective mobility. In addition to that, the influence of sodium and tris(hydroxymethyl)aminomethane as dodecyl sulphate counterions on th e effective mobility of micelles, efficiency and selectivity in MEKC a nalyses is evaluated.