On-column complexation of metal ions using 2,6-pyridinedicarboxylic acid and separation of their anionic complexes by capillary electrophoresis with direct UV detection

On-column complexation of metal ions with 2,6-pyridinedicarboxylate (2,6-PDC) to form anionic complexes enabled their separation by capillary zone electrophoresis with direct UV detection at 214 nm. Nine metal ions, Cu2+, Zn2+, Ni2+, Cd2+, Mn2+, Pb2+, Fe3+, Al3+ and Ca2+, were determined in less than 7 min using10 mM 2,6-PDC solution containing 0.75 mM tetradecyltrimethylammonium bromide at pH 4.0. Satisfactory working ranges (20–300 μM), detection limits (3–10 μM) and good repeatability of the peak areas (RSD 2.1–4.2%, n=5) were obtained using hydrodynamic injection (30 s). The proposed method was used successfully for the determination of Mn2+, Fe3+, Al3+ and Ca2+ in groundwaters.