On-line triple oxygen isotope analysis of nitrous oxide using decomposition by microwave discharge.
On-line triple oxygen isotope analysis of nitrous oxide using decomposition by microwave discharge.
复制标题
利用微波放电分解对一氧化二氮进行在线三氧同位素分析。
DOI：
10.1002/rcm.6698
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
R. Well
中科院分区：
文献类型：
--
作者：
Arata Mukotaka;S. Toyoda;N. Yoshida;R. Well
理由
N_2O和NO_3 ~-的氧同位素异常Δ（17）O对解释氮氧化物动力学是有用的。先前开发的Δ（17）O测量方法难以维持金管热分解N2 O为O2的最佳条件，并且Δ（17）O值也取决于样品大小。
方法
在石英管中，利用微波放电将5-40 nmol的N_2O定量分解为O_2。使用气相色谱法纯化O2。使用同位素比质谱法测量三重氧同位素。每个步骤都在线连接，并应用于分析在日本横滨收集的降水样品中的硝酸盐。
结果
当N_2O浓度大于20 nmol，Δ ~（17）O值较小（约为0.26‰）时，Δ ~（17）O分析的精密度（1σ）优于0.26‰。1‰）。当60 nmol以上的硝酸盐用蒸馏器法转化为N2 O，然后在所开发的系统上测量时，它优于0.76‰。降水样品中Δ（17）O值（14.5-26.4‰）与前人的研究结果一致。
结论
利用微波放电分解N2 O，建立了一种N2 O三氧同位素的在线分析方法。该方法操作简便，不需要对反应装置进行调整，适用于NO、NO2等N2 O以外的分子。
RATIONALE
The oxygen isotope anomaly, Δ(17)O, of N2O and nitrate is useful to elucidate nitrogen oxide dynamics. The previously developed method for Δ(17)O measurement presents difficulty in maintaining optimal conditions of the gold tube for thermal decomposition of N2O to O2 and the Δ(17)O value is also sample size dependent.
METHODS
Trace amounts (5-40 nmol) of N2O were decomposed quantitatively to O2 in a quartz tube by microwave discharge. The O2 was purified using gas chromatography. Triple oxygen isotopes were measured using isotope ratio mass spectrometry. Each step was connected online and was applied to the analysis of nitrate in precipitation samples collected in Yokohama, Japan.
RESULTS
Precision (1σ) of Δ(17)O analysis was better than 0.26‰ when more than 20 nmol of N2O with a small Δ(17)O value (approx. 1‰) was measured. It was better than 0.76‰ when more than 60 nmol of nitrate was converted into N2O using the denitrifier method and then measured on the developed system. The obtained Δ(17)O values in precipitation samples (14.5-26.4‰) agreed with findings from previous studies.
CONCLUSIONS
A novel on-line analytical method was developed to measure the triple oxygen isotopes of N2O using microwave discharge to decompose N2O. This easy-to-use method is free from conditioning of reaction devices, and is applicable to molecules other than N2O such as NO and NO2.
影响因子：
7.4
作者：
Kaiser, Jan;Hastings, Meredith G.;Sigman, Daniel M.
通讯作者：
Sigman, Daniel M.