Determination of metal ions by capillary electrophoresis using on-column complexation with 4-(2-pyridylazo)resorcinol following trace enrichment by peak stacking.

Co2+, Fe2+, Cu2+ and Zn2+ were separated and detected following derivatization with 4-(2-pyridylazo)resorcinol by capillary electrophoresis with UV-Vis detection. Parameters which were examined include both on-column and pre-column complexation, limit of detection, capillary loadability, linear dynamic range and reproducibility. A sample stacking technique was investigated in order to obtain better detection limits and greater sensitivity. Detection limits of 1 x 10(-8) M were achieved for Co2+, Fe2+ and Zn2+ and 4 x 10(-7) M for Cu2+. Mass detection limits were 0.2 fmol for Co2+, Fe2+ and Zn2+ and 7.0 fmol for Cu2+. The use of this method for the determination of metals in vitamin tablets and a pond water sample is presented.