Dissolved gas measurements in oceanic waters made by membrane inlet mass spectrometry
Dissolved gas measurements in oceanic waters made by membrane inlet mass spectrometry
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DOI：
10.4319/lom.2005.3.24
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发表时间：
2005-01
期刊：
影响因子：
--
通讯作者：
P. Tortell
中科院分区：
文献类型：
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作者：
P. Tortell
提出了一种用膜入口质谱法（MIMS）分析船舶海水中溶解气体（O2、CO2、Ar、N2、H2S、二甲硫化物）的方法。气体通过半透膜从海水中提取，进入质谱仪的离子源。该方法可以近实时地同时测量海水样品中的主要气体和痕量气体。在DMS的情况下，低nmol L−1的检测限可以实现没有任何浓度步骤。在亚北极太平洋进行的多次校准和方法比较表明，MIMS方法提供的气体测量结果与标准技术获得的结果一致，重复样品的精度在小于1%到大约5%的变异系数（CV）之间。为了说明MIMS方法的实用性，本文给出了亚北极太平洋各沿海和开放海洋站的O2、CO2、N2和DMS深度剖面图。除了这些离散的气体测量外，MIMS系统还被用于连续监测正在进行的样条沿线的气体浓度。沿两个沿海样带对O2、CO2和DMS进行的高频气体测量揭示了气体浓度在空间和时间上的高度变化，这可能是各种生物、化学和物理强迫的相互作用造成的。正在进行的MIMS数据为动态海水中气体循环的生物地球化学控制提供了见解。
A method is presented for the shipboard analysis of dissolved gases (O2, CO2, Ar, N2, H2S, dimethylsulfide) in oceanic waters using membrane inlet mass spectrometry (MIMS). Gases are extracted from seawater across a semipermeable membrane into the ion source of the mass spectrometer. The method can be used to simultaneously measure both major and trace gases in seawater samples in near real‐time. In the case of DMS, low nmol L−1 detection limits can be achieved without any concentration step. Multiple calibration and method comparison exercises conducted in the subarctic Pacific Ocean show that the MIMS method provides gas measurements that are consistent with those obtained by standard techniques, with precision of replicate samples ranging from less than 1% to approximately 5% coefficient of variation (CV). To illustrate the usefulness of the MIMS approach, depth profiles are presented for O2, CO2, N2, and DMS at various coastal and open ocean stations in the subarctic Pacific. In addition to these discrete gas measurements, the MIMS system has also been used to continuously monitor gas concentrations along underway transects. High frequency gas measurements of O2, CO2, and DMS made along two coastal transects reveal a high degree of spatial and temporal variability in gas concentrations, likely resulting from the interplay of various biological, chemical, and physical forcings. The underway MIMS data provide insight into the biogeochemical controls on gas cycling in dynamic marine waters.