ICP-MS测量天然淡水中的~(226)Ra

~(226) Ra是一种极毒的α放射性核素,是辐射环境监测中重点关注的核素之一。本工作建立了一种利用电感耦合等离子体质谱(ICP-MS)对天然淡水中~(226 )Ra快速定量分析的方法。对500mL的水样进行浓缩后,利用AG 50W-X8离子交换树脂和Sr萃取树脂分离基体质谱测量干扰元素(Ca、K、Mg、Na、Sr、Ba等),随后利用ICP-MS对~(226 )Ra进行定量分析。样品分析结果显示,~(226 )Ra全程加标回收率为90%~95%,~(226 )Ra的方法检测限为0.04pg/L(1.46mBq/L,n=10),整个流程耗时约10h。该方法实现了样品中~(226 )Ra的快速准确测量,为日常预警监测以及特殊情况应急中~(226) Ra监测提供了一条快捷可靠的途径。

ICP-MS for Determination of 226Ra in Natural Freshwaters

Due to the chemical toxicity and radioactivity (α emitter), ²²⁶Ra is one of the most important radionuclide for the environmental radioactivity monitoring. Herein, a rapid method for the determination of ²²⁶Ra in natural freshwaters by inductively coupled plasma mass spectrometry (ICP-MS) was established. In general, after the pre-concentration of water sample from 500 mL to 15 mL, separation of Ra from these potential interfering elements (i.e. Ca, K, Mg, Na, Sr and Ba ) was achieved using AG 50W-X8 ion exchange resins and Sr-resin, followed by the ICP-MS measurement. Results of four natural freshwater samples show that the ²²⁶Ra recovery range from 90% to 95%, and the detection limit of the methodology is determined to be 0.04 pg/L (1.46 mBq/L, n=10) for 500 mL sample. Compared to conventional radiometric techniques, the as-established method greatly shortens the analytical time for ²²⁶Ra determination (about 10 h), providing a rapid and reliable way for the determination of ²²⁶Ra in daily monitoring and emergency response.