Suppression of solute–wall interactions in humic acid capillary electrophoretic analysis by its diluted solution as background electrolyte

To analyze humic substances by capillary electrophoresis diluted humic acid (HA) solutions were used as a background electrolyte, resulting in the improved reproducibility of the analysis by suppressing the analyte interactions with capillary walls. Two HA solutions were investigated: standard HA solution and the Baltic Sea sediment HA extract. Characteristic shape electropherograms were obtained. Areas of the characteristic regions correlated linearly with the concentration of the injected HA sample.