Khan Asif Ali, Akhtar Tabassum
Analytical and Polymer Research Laboratory, Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh, India.
Anal Sci. 2008 Jul;24(7):881-7. doi: 10.2116/analsci.24.881.
A new heterogeneous precipitate of an organic-inorganic composite cation-exchanger poly-o-toluidine Zr(IV) phosphate was utilized for the preparation of a Hg(II) ion-sensitive membrane electrode for the determination of Hg(II) ions in real aqueous as well as in real samples. The electrode showed good potentiometric response characteristics, and displayed a linear log[Hg(2+)] versus EMF response over a wide concentration range of 1 x 10(-1) - 1 x 10(-6) M with a Nernstian slope of 30 mV per decade change in concentration with a detection limit of 1 x 10(-6). The membrane electrode showed a very fast response time of 5 s and could be operated well in the pH range 2 - 8. The selectivity coefficients were determined by the mixed-solution method, and revealed that the electrode was selective in the presence of interfering cations; however most of these did not show significant interference in the concentration range of 1 x 10(-1) - 1 x 10(-4) M. The lifetime of the membrane electrode was observed to be 120 days. The analytical utility of this electrode was established by employing it as an indicator electrode in the potentiometric titrations of Hg(2+) ions from a synthetic mixture as well as drain water.
一种新型的有机-无机复合阳离子交换剂聚邻甲苯胺磷酸锆非均相沉淀被用于制备汞（II）离子敏感膜电极，用于测定实际水样及实际样品中的汞（II）离子。该电极表现出良好的电位响应特性，在1×10⁻¹ - 1×10⁻⁶ M的宽浓度范围内，呈现出线性的log[Hg²⁺]与电动势响应，能斯特斜率为每十年浓度变化30 mV，检测限为1×10⁻⁶。该膜电极响应时间非常快，仅5 s，并且在pH值2 - 8范围内能良好工作。通过混合溶液法测定了选择性系数，结果表明该电极在存在干扰阳离子时具有选择性；然而，在1×10⁻¹ - 1×10⁻⁴ M浓度范围内，大多数干扰阳离子并未表现出显著干扰。观察到该膜电极的使用寿命为120天。通过将其用作指示电极，对合成混合物及排水中的汞（II）离子进行电位滴定，确立了该电极的分析实用性。
