Compound-specific hydrogen isotope analysis of fluorine-, chlorine-, bromine- and iodine-bearing organics using gas chromatography-chromium-based high-temperature conversion (Cr/HTC) isotope ratio mass spectrometry
Compound-specific hydrogen isotope analysis of fluorine-, chlorine-, bromine- and iodine-bearing organics using gas chromatography-chromium-based high-temperature conversion (Cr/HTC) isotope ratio mass spectrometry
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DOI：
10.1002/rcm.7872
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发表时间：
2017-07-15
影响因子：
2
通讯作者：
Gehre, Matthias
中科院分区：
文献类型：
--
作者：
Renpenning, Julian;Schimmelmann, Arndt;Gehre, Matthias
原理：传统的高温转化（HTC）方法对含卤（F, Cl, Br， I）有机物进行氢化合物特异性同位素分析（CSIA），由于产生HF， HCl， HBr和HI副产物，导致H-2产率不完全和相关的氢同位素分馏。此外，传统的高卤化化合物离线燃烧导致水作为氢同位素比质谱（IRMS）的中间化合物不完全回收，因此也导致同位素分馏。本研究提出了一种优化的铬基高温转化（Cr/HTC）方法，用于各种氟化、氯化、溴化和碘化有机化合物的氢CSIA。Cr/HTC方法快速、经济，且不受低H-2产率和相关同位素分馏的影响。方法：采用离子阱质谱仪对改进的气相色谱/铬基高温转化（GC-Cr/HTC）体系进行性能监测和优化。所有含卤化合物都实现了有机氢向H-2分析气体的定量转化。采用(i)离线转化为H2后的手动双入口(DI)-IRMS和（ii）元素分析仪(EA)-Cr/HTC-IRMS（在线转化）验证CSIA的相应准确性。结果：通过GC-Cr/HTC-IRMS对含F-、Cl-、Br-和i的有机物进行整体氢同位素分析，达到精密度sigma
RATIONALE: The conventional high-temperature conversion (HTC) approach towards hydrogen compound-specific isotope analysis (CSIA) of halogen-bearing (F, Cl, Br, I) organics suffers from incomplete H-2 yields and associated hydrogen isotope fractionation due to generation of HF, HCl, HBr, and HI byproducts. Moreover, the traditional off-line combustion of highly halogenated compounds results in incomplete recovery of water as an intermediary compound for hydrogen isotope ratio mass spectrometry (IRMS), and hence also leads to isotope fractionation. This study presents an optimized chromium-based high-temperature conversion (Cr/HTC) approach for hydrogen CSIA of various fluorinated, chlorinated, brominated and iodinated organic compounds. The Cr/HTC approach is fast, economical, and not affected by low H-2 yields and associated isotope fractionation.METHODS: The performance of the modified gas chromatography/chromium-based high-temperature conversion (GC-Cr/HTC) system was monitored and optimized using an ion trap mass spectrometer. Quantitative conversion of organic hydrogen into H-2 analyte gas was achieved for all halogen-bearing compounds. The corresponding accuracy of CSIA was validated using (i) manual dual-inlet (DI)-IRMS after off-line conversion into H2, and (ii) elemental analyzer (EA)-Cr/HTC-IRMS (on-line conversion).RESULTS: The overall hydrogen isotope analysis of F-, Cl-, Br- and I-bearing organics via GC-Cr/HTC-IRMS achieved a precision sigma