石墨炉原子吸收光谱法测定稀土中微量铕

STUDY ON THE DETERMINATION OF TRACE EUROPIUM IN RARE EARTHS BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROMETRY

本文对混合稀上中微量铕的石墨炉原子吸收光谱法测定进行了研究，比较了铕在热解涂层石墨管、普通石墨管及ＳＴＰＦ平台管中的原子化行为。用热解涂层石涂管研究了ＨＣＩ、ＨＣＩＯ４、ＨＮＯ３、Ｈ２ＳＯ４、Ｈ３ＰＯ４等对铕原子化的影响；研究了稀上及一些非稀土元素的干扰及其消除，基体盐类的背景吸收十扰的特征及消除方式等，最后用ＮＨ４ＣＩ作为基体改进剂，使灵敏度达到原来的１．９倍，有效地消除了大量其他稀土元素的干扰。从而建立广测定混合稀土中微量铕的方法。本法灵敏度为８×１０－３ｎｇ／０．００４４Ａ，线性范围０～１４４ｎｇＥｕ２Ｏ３／ｍｌ、对含０．７２μｇＥｕ２Ｏ３／ｍｌ的混合稀土样品的测定，其变异系数为３．７％。

The atomization behaviours of Eu in standard graphite tube, pyrolytically coated tube and STPF graphite tube were studied, and the effects of foreign elements on the determination of Eu were also studied. A sensitive method for the accurate determination of Eu in rare earths by GFAAS with pyrolytically coated tube and NH4CI as a matrix modifier was developed. Its sensitivity was enhanced by 190%, and no interference was found from other rare earth elements. Sensitivity of this method for Eu is 8 × 10-3 ng per 0. 0044A , and linear range for Eu2O3 is from zero to 144 ng ml-1. The relative standard deviation is 3. 7 % for 0. 72μg/mlEu.