次灵敏线火焰原子吸收光谱法测定稀土-镁中间合金中镁

Determination of magnesium in rare earth-magnesium intermediate alloy by atomic absorption spectrometry with hyposensitive line

以镁的202．5nm次灵敏线为分析线、火焰原子吸收光谱法测定了电解稀土-镁中间合金中的镁含量。考察了稀土基体及主要杂质的干扰情况，结果表明，钆、钇、钕3种稀土元素对镁的测定均有干扰，但在标准溶液中加入定量钆、钇、钕基体可消除干扰；测定溶液中主要杂质元素铁、铝、钨、钼的质量浓度在1μg／mL时，对10μg／mL镁的测定没干扰。镁的质量浓度在0～20μg／mL范围内呈良好线性关系。对钆-镁、钇-镁、钕-镁3种合金产品进行了检测并验证方法的精密度和准确度，RSD均小于2％，回收率在98％～102％范围内。本方法无需预先分离稀土，较常规EDTA滴定法简便、快速，适用于实际生产中量大而快速的检测需要。

The magnesium in rare earth-magnesium intermediate alloy was determined by flame atomic absorption spectrometry with the hyposensitive line of magnesium （202.5 nm） as the analytical line. The interferences of rare earth matrix and major impurities in alloys were investigated. The results showed that three rare earth elements including gadolinium, yttrium and neodymium had interferences with the determination of magnesium; however, the interferences could be eliminated by adding gadolinium, yttrium and neodymium matrixes into standard solutions quantitatively. When the mass concentration of major impurities including iron, aluminum, tungsten and molybdenum was 1 μg/mL, they had no interference with the determination of magnesium in 10 μg/mL. The linearity range of magnesium was 0-20 μg/mL. Magnesium contents in three master alloys of gadolinium-magnesium, yttrium-magnesium and neodymium-magnesium were determined and the precision and accuracy of the method were tested. The RSD was 〈2% and the recovery rates were in the range of 98 %--102 %. Thi＇s method is simpler and quicker than conventional EDTA titrimetry, for it need no pre-separation of rare earth, and thus it was suitable for the rapid determination for large amounts of samples.