Huang Wensheng, Yang Chunhai, Zhang Shenghui
Department of Chemistry, Hubei Institute for Nationalities, Enshi 445000, Hubei, PR China.
Anal Bioanal Chem. 2002 Nov;374(6):998-1001. doi: 10.1007/s00216-002-1438-0. Epub 2002 Aug 21.
A sodium montmorillonite (SWy-2)-modified carbon-paste electrode has been examined for determination of trace levels of mercury. Because of its strong cation-exchange and adsorptive characteristics, SWy-2 greatly improves the sensitivity of determination of Hg(2+). Hg(2+) is preconcentrated and reduced on the modified electrode surface at -0.40 V and then stripped from the electrode surface during the positive potential sweep. The conditions used for determination, e.g. supporting electrolyte, pH, amount of SWy-2, accumulation potential, and accumulation time, were optimized. The peak current was linearly dependent on the concentration of mercury from 1 x 10(-9) to 5 x 10(-7) mol L(-1). The detection limit (signal-to-noise ratio=3) was 1 x 10(-10) mol L(-1) after accumulation for 6 min. When the SWy-2-modified carbon-paste electrode was used to detect mercury in water samples the average recovery was 101.11%.
已对钠蒙脱石（SWy - 2）修饰的碳糊电极用于测定痕量汞进行了研究。由于其强大的阳离子交换和吸附特性，SWy - 2极大地提高了Hg(2+)测定的灵敏度。Hg(2+)在 - 0.40 V时在修饰电极表面预富集并还原，然后在正电位扫描期间从电极表面溶出。对测定所用条件，如支持电解质、pH值、SWy - 2的量、富集电位和富集时间进行了优化。峰电流与汞浓度在1×10(-9)至5×10(-7) mol L(-1)范围内呈线性关系。在6分钟富集后，检测限（信噪比 = 3）为1×10(-10) mol L(-1)。当使用SWy - 2修饰的碳糊电极检测水样中的汞时，平均回收率为101.11%。
