高压密封微波消解-石墨炉原子吸收光谱法检测进口铁矿石中镉含量

Determination of Cadmium in Iron Ore by High Pressure-airproof Microwave Digestion and Graphite Furnace Atomic Absorption Spectrometry

镉(Cd)是铁矿石中重点关注的微量有害元素。目前,铁矿石中镉含量的国家标准检测方法为ICP-Ms法。由于ICP-Ms设备昂贵,限制了方法的应用和推广。本文针对铁矿石和镉元素的特点,建立了盐酸-硝酸体系高压密封微波消解,石墨炉原子吸收光谱检测铁矿中镉含量的分析方法。通过实验确立了酸介质为1.5%硝酸+0.5%盐酸,基体改进剂为0.2%磷酸二氢铵,灰化温度为750℃,原子化温度为1550℃。通过基体匹配和加入基改剂,消除了基体干扰。在优化的条件下,测定镉元素检出限为0.05ug/L,方法精密度良好,回收率为96%~119.0%。本方法与ICP-Ms法的分析结果吻合,且简便快速、检测成本低。

Harmful element cadmium in iron ores has become one major concerns of environmental protection. The national standard method of the determination of Cd in iron ores uses ICP-Ms which is too expensive to be promoted.A simple and reliable method for the determination of cadmium in iron ores by graphite furnace atomic absorption spectrometry has been proposed. The sample was completely dissolved in HNO3-HCl solutions by high-pressure-airproof microwave digestion. The experimental conditions were optimized as follows:1.5% nitric acid + 0.5% hydrochloric acid as acid matrix, 0.2% ammonium dihydrogen phosphate as basic modifier, the ashing temperature is 750℃,and the atomization temperature is 1550℃. The matrix interferences were elimated by matrix matching and condition optimizing.The detection limit is 0.05 ug/L. The recovery is between 96% ~119.0%.The results of this method are in good agreement with those of ICP-MS, but with low cost.