INFINITE ELUTION RANGE IN MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY USING A NONIONIC/ANIONIC MIXED MICELLAR SYSTEM

摘要

The feasibility of increasing the elution range in micellar electrokinetic capillary chromatography (MEKC) was investigated using a nonionic/anionic mixed micellar system. The micellar ''pseudostationary'' phase was comprised of a mixture of nonionic (poly(oxyethylene)(23) dodecanol) and anionic (sodium dodecyl sulfate) surfactants. Variation in poly(oxyethylene)(23) dodecanol (Brij 35, Aldrich) concentration affected the electroosmotic and micellar electrophoretic mobilities differently. Equal but opposite electroosmotic and micellar electrophoretic velocities were obtained at a specific Brij 35 concentration, thereby producing a ''stationary'' micellar phase. Retention characteristics of a series of n-alkylphenone homologues suggested a nearly infinite elution range. Infinite elution ranges are possible at neutral pH (7.0) using deactivated fused-silica capillaries and at a pH of 6.2 using untreated fused-silica capillaries, [References: 25]