利用膜进样质谱连续走航测定表层海水O_2/Ar比值和pCO_2  

Continuous underway measurements of sea surface O_2/ Ar and pCO_2 by membrane inlet mass spectrometry

作　　者：郑文静[1] 韩玉[1] 秦川[1] 张桂玲[1] 

机构地区：[1]中国海洋大学海洋化学理论与工程技术教育部重点实验室,山东青岛266100

出　　处：《海洋环境科学》2016年第4期611-617,共7页Marine Environmental Science

基　　金：973课题"陆坡上生源要素输运和循环过程研究"(2014CB441502);973课题"营养元素循环的关键过程对多重压力的响应与反馈"(2011CB409802);国家自然科学创新研究群体科学基金"海洋有机生物地球化学"(41221004)

摘　　要：利用HIDEN公司HPR40溶解气体质谱分析仪,通过实验探索和实际应用,建立了连续走航高频率同时测定海水中O_2、Ar和CO_2等多种气体的分析方法。通过选择硅树脂膜的循环水取样器、进样流量为220 m L/min、进样平衡温度低于海水2℃等实验条件,建立了船载连续走航系统,实现了利用膜进样质谱仪(MIMS)连续走航测定表层海水O_2/Ar比值和p CO_2。所用仪器稳定性良好,连续测定12 h大气鼓泡48 h后的海水样品获得O_2、Ar和CO_2的精密度分别为1.57%、3.75%和2.21%,O_2/Ar的精密度为2.61%;该方法的重复性好,10 d内绘制7条CO_2工作曲线斜率的相对标准偏差RSD=4.18%。应用该方法在南海北部陆坡19.8°N^20.8°N,114.7°E^115°E断面进行调查并取得了很好的效果,结果表明:该调查断面的生物氧过饱和量Δ(O_2/Ar)为0.56%±1.02%,其变化范围为-2.52%至3.34%,调查断面的pCO_2值为361.53±40.46μatm。该方法具有直接、快速、高时空分辨率测定多种溶解气体的优点,为认识多组分气体的高分辨时空分布格局,深入开展我国陆架边缘海生物过饱和氧、海洋群落净生产力和pCO_2动力学研究提供了新方法。A continuous underway measurement of dissolved gases（ O_2,CO_2,Ar） in oceanic waters was developed using membrane inlet mass spectrometry（ MIMS,HPR-40,HIDEN,UK）. After optimizing experimental conditions,including sampling device,sampleing flow rate,sampling equilibrium temperature,we can use this method to determine the O_2/ Ar ratio and pCO_2 in the surface seawater. Laboratory experiments showed that the instrument yielded high signal stability and precision. The CV of the O_2,Ar,CO_2,O_2/ Ar value during 12 h continuous measurements was 1.57%,3. 75%,2. 21%,2. 61% for a same standard solution respectively. Seven standard calibration curves drawn within 10 days also showed high reproducibility with a relative standard deviation（ RSD） of 4. 18% for the seven slopes of standard calibration curves. The method was employed to determine O_2/ Ar ratio and pCO_2 in the north slope of the South China Sea（ 19. 8°N ～ 20. 8°N,114. 7°E ～ 115°E）. O_2/ Ar ranged from-2. 52% to 3. 34% with a meanof 0. 56% ± 1. 02%,and the mean of pCO_2 was 361. 53 ± 40. 46 μatm. This method can be used to measure dissolved gases（ O_2,CO_2,Ar） in oceanic waters directly,fast and with high spatial and temporal resolution,which provides a new approach to the research of net community production and pCO_2 in marginal seas of China.

关 键 词：氧氩比值(O2/Ar) CO2分压 膜进样质谱仪(MIMS) 

分 类 号：P734[天文地球—海洋化学]