PSEUDO-ELECTROCHROMATOGRAPHY NEGATIVE-ION ELECTROSPRAY MASS-SPECTROMETRY OF AROMATIC GLUCURONIDES AND FOOD COLORS

Pseudo-electrochromatography is a combination of liquid chromatography and an electromigration technique, especially directed at the separat ion of ionic compounds prior to mass spectrometric detection with a mo bile phase composition compatible with mass spectrometry. The applicat ion of pseudo-electrochromatography to the separation of food colours and aromatic glucuronides is described. An example of selectivity tuni ng by applying voltages of differing polarity during the chromatograph ic run is given. The coupling of pseudo-electrochromatography with ele ctrospray mass spectrometry is demonstrated. Differences in the effect s of the axial potential over the column between silica-based and poly meric packing materials are discussed.