用钨酸盐和耐尔蓝光度法测定痕量碲

Spectrophotometric Determination of Trace Tellurium (Ⅳ)With Tungstate and Nile Bule

报告一个简单、灵敏、快速光度测定碲的方法。聚乙烯醇（ＰＶＡ）存在下，碲与钨酸盐和耐尔蓝（ＮＢ）反应形成离子缔合物。离子缔合物的最大吸收峰位于５８０ｎｍ；表观摩尔吸光系数ε值为３．３３×１０７Ｌ·ｍｏｌ－１·ｃｍ－１。本方法允许的碲浓度范围为０～６．０μｇ／Ｌ；对４．８μｇ／Ｌ碲（Ｎ）测定的相对标准偏差为１．３％（ｎ＝１１）；检测限（３σ）为０.０１１μｇ／Ｌ（ｎ＝１２）。考察了许多离子的影响，大多数常见元素不干扰，可允许５００倍量Ｓｅ（Ⅳ）、２０倍量Ｇｅ（Ⅳ）、Ｓｂ（Ⅴ）和１０倍量Ｓｉ（Ⅳ）、Ｐ（Ⅴ）、Ａｓ（Ⅴ）存在。本法已用于烟尘中ｎｇ量碲的测定，回收率为９７％～１０２％，相对标准偏差为０．８％～４．５％。

A simple and sensitive method for rapid spectrophotometric determination of tellurium is described, which is based on the reaction of tellurium(Ⅳ) with sodium tungstate and Nile blue (NB) to form an ion-association complex in the presence of polyvinyl alcohol (PVA). The complex exhibits a maximum absorptivity at 580 nm, and its apparent molar absorptive coefficient is 3.33×107 L. mol-1. cm-1. The method allows the determination of tellurium concentrations in the range of 0-0.6 μg/L. The relative standard deviation for the determination of 4.0μg/L of tellurium is 1.3% (n=11), and the detection limit is 0.11 μg/L (n=12)。Most common ions do not interfere with the determination and 500-fold amounts of Se(Ⅳ), 20-fold amounts of Ge(Ⅳ), Sb(Ⅴ), 10-fold amounts of St(Ⅳ), P(Ⅴ), As(Ⅴ) and Cu(Ⅱ) were tolerated. The method can be applied to the spectrophotometric determination of nanogram amounts of tellruium (Ⅳ) in smoke ash with recoveries of 97-102% and RSD of 0.8% ~4.5%.