Analytical Sciences

Abstract − Analytical Sciences, 21(8), 955 (2005).

Determination of Heavy Metal Ions by Capillary Electrophoresis with Contactless Conductivity Detection after Field-amplified Sample Injection
Feng TAN, Bingcheng YANG, and Yafeng GUAN
Department of Analytical Chemistry and Micro-Instrumentation, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116012, China
A method has been developed for determining of heavy metal ions by field-amplified sample injection capillary electrophoresis with contactless conductivity detection. The effects of the 2-N-morpholinoethanesulfonic acid/histidine (MES/His) concentration in the sample matrix, the injection time and organic additives on the enrichment factor were studied. The results showed that MES/His with a low concentration in the sample matrix, an increase of the injection time and the addition of acetonitrile improved the enrichment factor. Four heavy metal ions (Zn2+, Co2+, Cu2+ and Ni2+) were dissolved in deionized water, separated in a 10 mM MES/His running buffer at pH 4.9 and detected by contactless conductivity detection. The detection sensitivity was enhanced by about three orders of magnitude with respect to the non-stacking injection mode. The limits of detection were in the range from 5 nM (Zn2+) to 30 nM (Cu2+). The method has been used to determine heavy metal ions in tap water.