Humic acid capillary zone electrophoresis adsorption on capillary walls, separation in metal ion supplemented buffer and the fingerprints

Capillary zone electrophoresis (CZE) in quartz tubes is often being used for the separation and characterization of humic acids (HA). A method was found to follow adsorption (and kinetics) of humic acids on a fused-silica capillary wall. It was shown that the adsorption of humic acids on an uncoated capillary wall is high. The effect on sorption of additives to the background electrolyte (BGE) was studied. Sorption can be eliminated by adding magnesium(II) salts (14–50 mM) to the BGE (pH 3.40) with resultant highly reproducible electropherograms as well as detailed and expressive fingerprints for HA of different origin.