Determination of the 15N/14N, 17O/16O, and 18O/16O ratios of nitrous oxide by using continuous-flow isotope-ratio mass spectrometry
Determination of the 15N/14N, 17O/16O, and 18O/16O ratios of nitrous oxide by using continuous-flow isotope-ratio mass spectrometry
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DOI：
10.1002/rcm.3493
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发表时间：
2008-05-01
影响因子：
2
通讯作者：
Tsunogai, Urumu
中科院分区：
文献类型：
--
作者：
Komatsu, Daisuke D.;Ishimura, Toyoho;Tsunogai, Urumu
我们开发了一种快速，灵敏，自动化的分析系统，以确定Δ N-15，Δ O-18，和Δ O-17值的一氧化二氮（N2 O）同时在纳摩尔量为一批样品的连续流同位素比质谱法（CF-IRMS），没有任何繁琐和耗时的预处理。该分析系统包括一个真空线，以提取和纯化N2 O，气相色谱仪进一步纯化N2 O，一个可选的热炉分解N2 O到O-2，和CF-IRMS系统。我们还在系统中使用了气动阀和气动执行器，以便我们可以在个人计算机上通过定时软件自动操作。对于单次测量，分析精度对于Δ N-15（具有>4 nmol N2 O注入）优于0.12份千分之一，对于Δ O-18（具有>4 nmol N2 O注入）优于0.25份千分之一，并且对于Δ O-17（具有>20 nmol N2 O注入）优于0.20份千分之一。通过使用自动分析系统对190 nmol样品进行四次以上重复的多次分析，我们还能够轻松地将精密度（标准误差）提高到Δ N-15优于0.05 ppm，Δ O-18优于0.10 ppm，Δ O-17优于0.10 ppm。利用该系统，不仅可以对大气样品中的N_2O的Δ N-15、Δ O-18和Δ O-17进行定量，而且还可以对其它低N_2O含量的气体或液体样品（如土壤气体或天然水）进行定量。在这里，我们展示了有史以来第一次Delta O-17土壤N2 O测量。版权所有（C）2008约翰威利父子有限公司
We developed a rapid, sensitive, and automated analytical system to determine the delta N-15, delta O-18, and Delta O-17 values of nitrous oxide (N2O) simultaneously in nanomolar quantities for a single batch of samples by continuous-flow isotope-ratio mass spectrometry (CF-IRMS) without any cumbersome and time-consuming pretreatments. The analytical system consisted of a vacuum line to extract and purify N2O, a gas chromatograph for further purification of N2O, an optional thermal furnace to decompose N2O to O-2, and a CF-IRMS system. We also used pneumatic valves and pneumatic actuators in the system so that we could operate it automatically with timing software on a personal computer. The analytical precision was better than 0.12 parts per thousand for delta N-15 with >4 nmol N2O injections, 0.25 parts per thousand for delta O-18 with >4 nmol N2O injections, and 0.20 parts per thousand for Delta O-17 with >20 nmol N2O injections for a single measurement. We were also easily able to improve the precision (standard errors) to better than 0.05 parts per thousand for delta N-15, 0.10 parts per thousand for delta O-18, and 0.10 parts per thousand for Delta O-17 through multiple analyses with more than four repetitions with 190 nmol samples using the automated analytical system. Using the system, the delta N-15, delta O-18, and Delta O-17 values of N2O can be quantified not only for atmospheric samples, but also for other gas or liquid samples with low N2O content, such as soil gas or natural water. Here, we showed the first ever Delta O-17 measurements of soil N2O. Copyright (C) 2008 John Wiley & Sons, Ltd.