ONLINE COUPLING OF MICELLAR ELECTROKINETIC CHROMATOGRAPHY TO ELECTROSPRAY MASS-SPECTROMETRY

The possibility of selectivity enhancement in capillary electrophoresi s-mass spectrometry (CE-MS) by hyphenating micellar electrokinetic chr omatography (MEKC) and electrospray mass spectrometry (MS) is describe d for two quaternary ammonium compounds. Direct coupling of MEKC to MS is hazardous because of the contamination of the ion source due to pr esence of an excess of micelle forming agent in the MEKC buffer. There fore, a coupled-capillary setup with the possibilities of voltage swit ching and buffer renewal has been designed. Such a system allows on-li ne heartcutting of the zones of interest in the MEKC capillary with su bsequent transfer via a second capillary to the mass spectrometer.