示波催化极谱法测定高纯铅中痕量硒

CATALYTIC OSCILLOPOLAROGRAPHIC DETERMINATION OF TRACES OF SELENIUM IN HIGH-PURITY LEAD

在氨水 -氯化铵 -亚硫酸钠 -高碘酸钾混合底液中 ,硒产生灵敏的催化极谱波 ,测定起始电位为 - 0 .64V,峰电位为 - 0 .84 V( vs.SCE) ,一阶导数法测定 ,硒含量在 0～ 5.0 μg.L- 1 范围内与峰电流呈线性 ,检出限为 0 .1μg.L- 1 。以硫酸铅沉淀分离主体铅 ,可测定高纯铅中 w Se2× 1 0 - 5%～ x× 1 0 - 4 ,方法灵敏。试验了高纯铅中 2 0余种共存离子的干扰 ,方法具有很好的选择性 ,其他共存杂质元素均不干扰。用于高纯铅中痕量硒测定 ,加标回收率为 96%～ 99% ,RSD为 9.1 %～ 1 1 % ,测定结果与二氨基联苯胺光度法一致 ,方法简便、灵敏、准确。

It is found that in a base solution containing aqueous ammonia, ammonium chloride, sodium sulfate and potassium periodate, a sensitive catalytic polarographic wave of selenium is obtained, with its initial potential at -0.64V( vs .SCE) and its peak potential at -0.84V( vs .SCE). By using the first derivative method, a linear relationship between the concentration of selenium and the peak current is obtained in the range of 0~5.0μg·L -1 . The limit of detection of this method is found to be 0.1μg·L -1 . After the precipitation of the matrix element as PbSO 4, the method can be used to determine selenium in the range 2×10 -5 %~2×10 -4 %. No remarkable interference is observed by the co existing elements. Recoveries between 96%~99% are found by the standard addition method, and the RSD found are 9.1%~11%. The results obtained by this method checked very well with those obtained by the conventional photometric method.