应用微波消解-ICP-MS法分析环境水样中的钍

采用微波消解对环境水样进行前处理、应用电感耦合等离子体质谱法(ICP-MS)快速测定环境水样中钍含量，对测量条件和微波消解条件进行了优化，并从内标的选择、检出限、精密度、准确度、回收率以及实际样品测量等方面对结果进行分析。结果表明：以209Bi为内标分析水中钍时，测量结果的相对偏差最小，为0.2%～1.3%；该方法检出限为0.003 μg/L；考察了4个浓度水平下的方法精密度，相对标准偏差（s_r）均小于6.0%(n=6)；进行了3个不同浓度水平下的标准物质测量和加标回收率实验，测定值与标准值基本吻合，加标回收率为93.4%～106.2%；对20个实际环境水样中钍质量浓度进行了测量，测定结果在2016年测量值范围之内，验证了该法测量环境水样中钍含量的实用性。

Determination of Thorium in Environmental Water by Microwave Digestion-ICP-MS

In this article, the microwave digestion method was used to pretreat the environmental water samples, and the inductively coupled plasma mass spectrometry(ICP-MS) was used to rapidly determine the thorium content in the environmental water samples. The measurement and microwave digestion conditions were optimized. The results were analyzed in the aspects of selection of internal standard, detection limits, precision, accuracy, recovery, and actual sample measurements. The experimental results show that the relative deviation of measurement when analyzing thorium in water with 209Bi as the internal standard is the smallest, 0.2%-1.3%; the detection limit of this method is 0.003 μg/L. The precision of the method was investigated. The relative standard deviation(s_r) of the determination results is less than 6.0%(n=6). The reference material measurement and spiked recovery experiments were carried out at three different concentration levels. The measured values are basically consistent with the certified values, and the recoveries are 93.4%-106.2%. Twenty actual environmental water samples were measured. The results are within the range of results measured in 2016, which verifies the practicability of this method in measuring thorium content in environmental water samples.