Applications of partial filling micellar electrokinetic chromatography: from electrospray mass spectrometry to fluorescence polarization immunodetection

Abstract

The potential interference of surfactants used in micellar electrokinetic chromatography (MEKC) with on-line detection methods has limited the application of MEKC. We present a solution for eliminating the elution of surfactant used in MEKC into detectors. In comparison to conventional MEKC our separation method involves filling the capillary with a small plug of surfactant. We have coined this separation mode as partial filling micellar electrokinetic chromatography (PF-MEKC). The capillary in PF-MEKC is filled with electrophoresis buffer, followed by an introduction of micellar solution, and finally the sample injection. In PF-MEKC analytes first migrate into the micellar plug where the separation occurs, and then into the electrophoresis buffer which is free of surfactants, while the micellar plug remains in the capillary. Therefore, the elution of the analytes into a given detector occurs in the electrophoresis buffer. As a result, PF-MEKC provides a solution for coupling MEKC separation technique on-line to various detectors. Before the application of PF-MEKC can be realized, it is important to investigate the overall mechanism and the effects PF-MEKC on analyte separation efficiency and resolution. The first paper in this work presents a theoretical model for predicting the separation behavior of triazine herbicides in PF-MEKC. The comparison between conventional and PF-MEKC in terms of separation eflHciency and resolution of the triazines herbicides are presented and