摘要
报道了双硫腙修饰玻碳电极同时测定痕量镉和铅的电分析方法。镉和铅离子通过与电极表面的双硫腙发生螯合作用而富集在电极表面 ,同时在 -1 .2 0V(vs.SCE)还原成零价镉和铅 ,当电极电势从 -1 .2 0V向 -0 .3 0V扫描时 ,被还原的镉和铅从电极表面溶出 ,分别于 -0 .78V和 -0 .4 8V左右形成灵敏的阳极溶出峰。优化了支持电解质及pH值、双硫腙用量、富集电位及时间等实验参数。利用该修饰电极测定镉、铅的线性范围分别为 1 .0×1 0 - 8～ 2 .5× 1 0 - 6 mol L和 5 .0× 1 0 - 9～ 2 .5× 1 0 - 6 mol L。检测限分别为 5 .0× 1 0 - 9mol L和7.0× 1 0 - 1 0 mol L。该法用于实际水样中镉和铅的测定 ,平均回收率分别为 99.3 0 %和 99.5 4 %。
Dithizone-modified glassy carbon electrode has been investigated to detect trace levels of Cd2+ and Pb2+, Cd2+ and Pb2+ are preconcentrated on the surface of the dithizone-modified glassy carbon electrode at - 1.20 V(vs. SCE), and subsequently reduced on the electrode. In the following step, reduced cadmium and lead are oxidized, and voltammograms are recorded by scanning the potential towards a positive direction. The peak currents are linear with the concentrations in the range of 1.0 x 10(-8) similar to 2.5 x 10(-6) mol/L for Cd2+ and of 5.0 x 10(-9) similar to 2.5 x 10(-6) mol/L for Pb2+. The detection limits are 5.0 x 10(-9) mol/L for Cd2+ and 7.0 x 10(-10) mol/L for Pb2+. The relative standard deviation, determined on one single electrode at a concentration of 1.0 x 10(-6) mol/L Cd2+ and Pb2+, has been calculated to be 3.1% for Cd2+ and 3.0% for Pb2+ (n = 6). Using this modified electrode, trace levels of Cd2+ and Pb2+ in several water samples were determined, and the average recovery is 99.30% (Cd2+) and 99.54% (Pb2+).
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
2002年第11期1367-1370,共4页
Chinese Journal of Analytical Chemistry
基金
湖北省教育厅重点项目 (No .2 0 0 2 0 0 80 10 )
