Separation and determination of six metal cations by capillary zone electrophoresis

Abstract

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+, Zn2+, Mn2+, Pb2+ and Cd 2+ canbe achieved within 5 min. Anew 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 anorganic modifier, by using acetic acid to adjust the pH=4.40 was developed. The applied voltage was 20 kV at 25°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 (Zn̂mg-L1. 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. © 2008 Sociedad Chilena de Química.