High-precision, automated stable isotope analysis of atmospheric methane and carbon dioxide using continuous-flow isotope-ratio mass spectrometry
High-precision, automated stable isotope analysis of atmospheric methane and carbon dioxide using continuous-flow isotope-ratio mass spectrometry
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DOI：
10.1002/rcm.2300
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发表时间：
2006-01-01
影响因子：
2
通讯作者：
Nisbet, EG
中科院分区：
文献类型：
--
作者：
Fisher, R;Lowry, D;Nisbet, EG
小规模开发了现成的连续流气相色谱/同位素比质谱（CF-GC/IRMS）系统，以便对环境浓度下的甲烷（CH 4）和二氧化碳（CO2）进行高精度同位素分析。对于一个标准储罐的10次连续分析，该系统可获得的重复性（1 sigma）为CH 4的δ（13）C为0.05份/千，CO2的δ（13）C为0.03份/千，CO2的δ（18）O为0.05份/千。一个自动化的入口系统，它允许昼夜研究的CO2和CH 4同位素，也被描述。通过在燃烧炉中使用钯粉/石英棉催化剂，提高了CH 4氧化成CO2的效率，实现了CH 4分析的精度提高。自动进样通过保持常规恒定，进一步提高了CH 4和CO2分析的精度。所描述的方法提供了一个快速的样本周转，准确，可重复的结果，并允许在一个网站的甲烷或二氧化碳同位素的长期连续记录，提供有关变化的气体来源的信息季节性和年际。版权所有（c）2005年约翰威利父子有限公司。
Small-scale developments have been made to an off-the-shelf continuous-flow gas chromatography/isotope-ratio mass spectrometry (CF-GC/IRMS) system to allow high-precision isotopic analysis of methane (CH4) and carbon dioxide (CO2) at ambient concentrations. The repeatability (1 sigma) obtainable with this system is 0.05 parts per thousand for delta(13)C of CH4, 0.03 parts per thousand for delta(13)C of CO2, and 0.05 parts per thousand for delta(18)O of CO2 for ten consecutive analyses of a standard tank. An automated inlet system, which allows diurnal studies of CO2 and CH4 isotopes, is also described. The improved precision for CH4 analysis was achieved with the use of a palladium powder on quartz wool catalyst in the combustion furnace, which increased the efficiency of oxidation of CH4 to CO2. The automated inlet further improved the precision for both CH4 and CO2 analysis by keeping the routine constant. The method described provides a fast turn-around in samples, with accurate, reproducible results, and would allow a long-term continuous record of CH4 or CO2 isotopes at a site to be made, providing information about changing sources of the gases both seasonally and interannually. Copyright (c) 2005 John Wiley & Sons, Ltd.