Separation and Determination of Six Metal Cations by Capillary Zone Electrophoresis

A rapid, simple and reliable method was devised for separation and determination of six metal cations, based on the capillary zone electrophoresis.The results showed that the complete separation of K + ,Cu 2+ , Zn 2+ , Mn 2+ , Pb 2+ and Cd 2+ can be achieved within 5 min.A new electrolyte system containing 15 mmol•L -1 imidazole as a background absorbance reference and 8 mmol•L -1 malonic acid, 2 mmol•L -1 18-crown-6 ether as the complexing agents, 10% methanol as an organic modifier, by using acetic acid to adjust the pH=4.40 was developed.The applied voltage was 20 kV at 25 o C.Under the optimum conditions, 6 ions were separated and determined with the correlation coefficient of 0.9984-0.9993.The detection limits (S/N=3) from 0.05 (K + ) to 0.75 (Zn 2+ ) mg•L -1 .The repeatability of migration times was less than 0.60% and of peak area ranged from 3.4 to 5.6% (n=6).The results were compared with AAS for analyzing the real samples of waste-water and snow water.