Centre for Hydrogeology and Geothermics (CHYN), University of Neuchatel, Rue Emile Argand 11, 2000 Neuchatel, Switzerland.
Centre for Hydrogeology and Geothermics (CHYN), University of Neuchatel, Rue Emile Argand 11, 2000 Neuchatel, Switzerland.
J Chromatogr A. 2014 Jan 17;1325:16-22. doi: 10.1016/j.chroma.2013.11.055. Epub 2013 Dec 4.
An investigation was carried out to develop a simple and efficient method to collect vapour samples for compound specific isotope analysis (CSIA) by bubbling vapours through an organic solvent (methanol or ethanol). The compounds tested were benzene and trichloroethylene (TCE). The dissolution efficiency was tested for different air volume injections, using flow rates ranging from 25ml/min to 150ml/min and injection periods varying between 10 and 40min. Based on the results, complete mass recovery for benzene and TCE in both solvents was observed for the flow rates of 25 and 50ml/min. However, small mass loss was observed at increased flow rate. At 150ml/min, recovery was on average 80±17% for benzene and 84±10% for TCE, respectively in methanol and ethanol. The δ(13)C data measured for benzene and TCE dissolved in both solvents were reproducible and were stable independently of the volume of air injected (up to 6L) or the flow rate used. The stability of δ(13)C values hence underlines no isotopic fractionation due to compound-solvent interaction or mass loss. The development of a novel and simple field sampling technique undertaken in this study will facilitate the application of CSIA to diverse gas-phase volatile organic compound studies, such as atmospheric emissions, soil gas or vapour intrusion.
进行了一项研究，旨在开发一种通过将蒸气通过有机溶剂（甲醇或乙醇）鼓泡来收集用于化合物特异性同位素分析（CSIA）的蒸气样品的简单有效的方法。测试的化合物为苯和三氯乙烯（TCE）。使用流速范围为 25ml/min 至 150ml/min 且注入时间在 10 至 40min 之间，对不同的空气体积注入进行了溶解效率测试。基于结果，对于 25 和 50ml/min 的流速，在两种溶剂中均观察到苯和 TCE 的完全质量回收。然而，在增加的流速下观察到少量质量损失。在 150ml/min 时，苯和 TCE 在甲醇和乙醇中的回收率平均分别为 80±17%和 84±10%。在两种溶剂中溶解的苯和 TCE 的 δ(13)C 数据是可重现的，并且独立于注入的空气体积（高达 6L）或使用的流速而稳定。因此，δ(13)C 值的稳定性强调了由于化合物-溶剂相互作用或质量损失而没有同位素分馏。本研究中进行的新型简单现场采样技术的开发将促进 CSIA 在各种气相挥发性有机化合物研究中的应用，例如大气排放、土壤气体或蒸气入侵。
