| 多接收电感耦合等离子体质谱测定氙同位素比值研究 |
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| 基金项目:国家重点研发计划资助（2021YFF0700100） |
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| 中文摘要:核爆炸产生的氙（Xe）同位素是全面禁止核试验条约的重要监测对象。该文建立了大气气溶胶中Xe同位素比值的多接收电感耦合等离子体质谱（MC－ICP－MS）分析方法。通过研发Xe的富集纯化平台，使用高纯氩气（99.999%）为载体，有效降低了大气气溶胶中残留颗粒物和有机物对质谱测量的影响。为提高信号稳定性，建立了MC－ICP－MS专用Xe气体进样系统，通过活性炭吸附质谱样品气的Xe、气体进样系统烘烤和抽真空2 h等措施，有效降低了记忆效应和系统本底，129Xe的本底信号强度从3.0 × 10-2 V降至小于2.7 × 10-3 V，Xe本底对样品比值测量的影响小于万分之一。采用标准样品交叉法校正质量分馏效应，在24 h内穿插测量7次Xe质控标样，Xe同位素比值测量精密度小于0.09%，对130Xe/131Xe和132Xe/131Xe测量精密度小于0.008%，测量结果与参考值在不确定度范围内一致。采用该方法有效鉴别了Xe同位素组成存在差异的实际样品。该文建立的Xe同位素比值的MC－ICP－MS测量技术精密度高，结果准确，可为Xe监测事件识别及溯源等研究提供可靠数据。 |
| 中文关键词:氙同位素比值 Xe富集纯化平台 Xe气体进样系统 多接收电感耦合等离子体质谱（MC－ICP－MS） |
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| Determination of Xenon Isotope Ratios by Multiple Collector Inductively Coupled Plasma Mass Spectrometry |
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| Abstract:Xenon（Xe） isotopes from nuclear test and accidents are important monitoring components of the comprehensive nuclear test ban treaty（CTBT）．An approach for the reproducible and accurate compositional analysis of Xe isotope ratios by multiple collector inductively coupled plasma mass spectrometry（MC－ICP－MS） was described in this paper．A Xe enrichment and purification platform was established to separate Xe from the collected atmosphere gas，enriching the Xe concentration and utilizing high purity argon as aerosol carrier，thus resulting in eliminating the negative influences of organic compound and particles on mass spectrometry．A relible Xe injection system was built to control the gas flow rate between the sample and the MC－ICP－MS in order to improve the stability and reproducibility of the ion-signals．Furthermore，several measures，including adsorbing Xe from the sample gas for mass spectrometry and baking the Xe introduction device for 2 hours with vaccum pumping，were taken to reduce the Xe blank．As a result，the blank signal of 129Xe falled from 3.0 × 10-2 V to 2.7 × 10-3 V．Analyses were performed on a Neptune XT MC－ICP－MS，and standard sample bracketing（SSB） was involved in correcting the mass fractionation．The approach was successfully validated by the measurement of standard reference materials in 24 hours，showing that the relative uncertainties for all Xe isotope ratios were less than 0.09%（n = 7），while the results agreed with the certificated values within uncertainty range．Especially，the relative uncertainties for 130Xe/131Xe and 132Xe/131Xe ratios were 0.007 1% and 0.006 9%，respectively．Two kinds of atmosphere gas collected at different times were analyzed and distinguished successfully by the proposed approcach．The results demonstrated that the developed technique was a precise and accurate method for Xe isotope dectection，Xe monitoring event identification and event sourcing. |
| Key Words:xenon isotope ratios Xe enrichment and purification device Xe injection system multiple collector inductively coupled plasma mass spectrometry（MC－ICP－MS） |
| 引用本文：汪伟，席瑞阳，郭思琪，徐江，康泰，韦冠一，李雪松，李萌，李志明，陈彬，王亚龙，粟永阳.多接收电感耦合等离子体质谱测定氙同位素比值研究[J].分析测试学报,2023,(4):473-479. |
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