质谱法测定水中溶解氙的含量及其同位素组成

利用设计的一套水样中提取并分离Xe的装置,与稀有气体质谱仪Helix SFT联用,建立了高精度水中溶解Xe的含量及其同位素组成的分析方法。对该装置的密封性及本底进行检测,证明此方法可靠；循环升温-降温法分离Xe气中大量Ar的方法,可在短时间内除掉绝大部分Ar,减小其对Xe含量及同位素组成的测试影响。该方法的检出限可低至10-13~10-14 L/L；对空气饱和水进行测试, Xe 含量、129 Xe/131 Xe 和132 Xe/134 Xe的测试结果的相对标准偏差分别为1.00%,0.10%和0.20%,误差分别为0.93%,0.16%和0.50%；分析了造成测试误差的因素,明确了误差的来源。

Determination of Dissolved Xe Concentration and Isotope Composition in Water by Mass Spectrometry

A method was established to analyze the dissolved Xe concentration and Xe isotopes in water precisely with the self-design device of Xe extraction and separation line in combining with the Helix SFT noble gas mass spectrometer. The leak test and the background determination of the whole system proved the system was reliable. The large amount of Argon from Xe could be effectively removed by cycling temperature rising and falling method, which resulted in the elimination of the interference to the analysis of Xe concentration and isotopes. The limit of detection of the method for Xe concentration could reach as low as 10-13-10-14 L/L. The method was used for the measurement of the dissolved Xe in air saturated water (ASW), and the RSDs of Xe concentration, 129Xe/ 131Xe and 132Xe/ 134Xe were 1. 0%, 0. 10% and 0. 20%respectively, while the errors were 0. 93%, 0. 16% and 0. 50% respectively.