建立了电感耦合等离子体原子发射光谱(ICP-AES)测定超导粉中痕量铁的新方法。 优化了仪器工作参数, 对痕量铁测定时的基体干扰及消除干扰的方法进行了系统研究, 结果表明: 大量存在的基体元素产生一定基体效应, 并使重现性变差, 且由于铁含量甚微, 仪器灵敏度不能满足测定的要求, 需采用分离富集方法以提高测定结果的准确度和精密度。 以三乙醇胺掩蔽基体元素铋和铜, 在适宜的酸度条件下, 铁与邻二氮菲生成配合物, 以活性炭定量吸附, 用1∶1硝酸解吸, 并对分离富集条件进行了优化。 对模拟标准样品进行测定, 分析结果与理论值一致, 相对标准偏差为2.4%, 方法检出限为0.033 μg·g-1。 该方法已用于超导前驱粉样品中痕量铁的分析, 结果令人满意, 并进行了回收实验, 回收率为95.6%～98.0%。

A new method for determination of trace iron in superconductor powder by ICP-AES was proposed. The instrument parameters were optimized, and the matrix effects as well as the method of eliminating interferences were also studied systemically. The results showed that matrix interference was serious when the amount of matrix increased, and the repeatability was poor, so it was necessary that separation and preconcentration were used to improve the accuracy and precision. In the experiment, complex was formed with Fe and phenanthroline after the matrix elements Bi and Cu were masked by triethanolamine in an appropriate acidity condition. Then the complex was quantitatively adsorbed by activated carbon, and desorbed by 1∶1 HNO3. The enrichment conditions were investigated in detail. Under the optimal condition, an artificial sample was analysed, and the result was identical with reference values, with the RSD and detection limit being 2.42% and 0.033 μg·g-1, respectively. The method was applied for the determination of trace iron in Bi-based superconductor powder samples with satisfactory results, in which the recoveries experiment was performed with the recovery coefficient falling in the range of 95.6% to 98.0%.