Evaluation of different electrolyte systems and on-line preconcentrations for the analysis of haloacetic acids by capillary zone electrophoresis.

This study compares the sodium chromate, potassium hydrogenphthalate, 2,6-naphthalenedicarboxylic acid dipotassium and sodium tetraborate electrolyte systems, for determining haloacetic acids using capillary zone electrophoresis with and without modified electroosmotic flow. In order to detect low concentrations of these compounds, an on-line preconcentration step was carried out. Results were good when standard solutions were analysed, but when the method was applied to real samples, the sample had to be pretreated to decrease the interference of the matrix. For this reason, a solid-phase extraction process with LiChrolut EN cartridges was applied to clean up the sample before the injection.