A POTENTIOMETRIC DETECTION TECHNIQUE FOR CHELATING-AGENTS AFTER SEPARATION BY CAPILLARY-ZONE-ELECTROPHORESIS

The combination of capillary zone electrophoresis with potentiometric detection has been investigated for the determination of chelating age nts such as diethylenetriaminepentaacetic acid. The detector consists of a metallic copper electrode with a diameter of 100 mu m arranged in an end-capillary configuration. The electrode potential depends on th e concentration of copper ions at the electrode surface and therefore decreases when chelating agents pass the electrode. In combination wit h UV detection, both free ligands and metal complexes could be detecte d.