硒(Ⅳ)-碘酸钾体系极谱法测定痕量亚硫酸根

Polarographic Determination of Trace Sulfite With Selenite-Potassium Iodate System

报道了一种单扫描极谱测定痕量亚硫酸根的方法。在高氯酸介质中，亚硫酸根可将 Ｓｅ（Ⅳ）还原为 Ｓｅ（０），在 ｐＨ １０．５的 ＮＨ３－ＮＨ４Ｃｌ缓冲溶液中，在碘酸钾存在下，于－０．９０ Ｖ （ｖｓ．ＳＣＥ）处产生一个灵敏的还原催化波，导数波高与亚硫酸根浓度在０～０．４ ｍｇ／Ｌ范围内 有线性关系，检出限为 ２ μｇ／Ｌ。研究了极谱波的性质，讨论了电极过程机理。应用本法测定了 空气中二氧化硫的含量。

A method for polarographic determination of sulfite is described. In 0. 2 mol/L HClO4 solution, Se(Ⅳ ) was reduced to metal Se by sulfite. In pH l0. 5 NH3-NH4Cl buffer solution containing KIO3, a sensitive polarographic wave was obtained at -0. 90 V (vs. SCE), and the derivative wave height is lineary proportional to sulfite concentration in the range of 0-0. 4 mg/L, and the detection limit is 2μg/L. The electrochemical behaviour has been studied and the electrode process is discussed. The method has been applied to the determinaton of sulfite in air with satisfactory resu1ts.