Description of a Dimethylmercury Automatic Analyzer for the High-Resolution Measurement of Dissolved Gaseous Mercury Species in Surface Ocean Waters
Description of a Dimethylmercury Automatic Analyzer for the High-Resolution Measurement of Dissolved Gaseous Mercury Species in Surface Ocean Waters
复制标题
用于高分辨率测量表层海水中溶解气态汞形态的二甲基汞自动分析仪的描述
DOI：
10.1021/acs.est.2c02908
复制
发表时间：
2022
影响因子：
11.4
通讯作者：
Mason, Robert P.
中科院分区：
文献类型：
--
作者：
He, Yipeng;Shi, Xiangming;Huffman, Wesley W.;Lamborg, Carl H.;Mason, Robert P.
由于缺乏对水体中二甲基汞（DMHg）的详细测量，我们对DMHg在汞（Hg）全球海洋生态地球化学循环中的重要性的认识尚不清楚。据我们所知，30年来发表的研究在海洋表面沃茨和海洋边界层（MBL）中产生的DMHg数据点不超过200个。为提高表层海水中二甲汞测定的精密度和降低不确定度，研制了一种简单、耐用的二甲汞自动分析仪。该DAA系统耦合了主要的采样和分析步骤，包括连续流动室，双Carbotrap预浓缩，气相色谱柱，冷蒸气原子荧光光谱法和用于信号积分的数据记录器。我们比较了我们的DAA和传统的手工分析方法之间的操作，性能和重现性。其优点包括操作简便，时间分辨率和精密度高（30 min采样，相对变异<5%），长期稳定性（2周）。DAA可同时测定MBL和表层海水中的DMHg。DAA对大气和表层海水中DMHg的估计检出限分别为10 pg/m3和0.2 fM。在近海沃茨成功的DAA现场测量表明，它可以帮助检测表层海水中的低浓度DMHg，时间序列DMHg数据有助于我们了解DMHg的行为（源和汇）和它进入MBL的通量。不同海洋中DMHg浓度的比较也表明，沿海地区的DMHg平均值最低，比其他生态系统低一个数量级。
Our understanding of the significance of dimethylmercury (DMHg) to the mercury (Hg) global ocean biogeochemical cycle is unclear because of the lack of detailed DMHg measurements in the water column. To our knowledge, 30 years of published studies have generated no more than 200 DMHg data points in the ocean surface waters and marine boundary layer (MBL). To improve the precision and reduce the uncertainty in determining DMHg in surface seawater, we developed a simple and robust DMHg automatic analyzer (DAA). This DAA system couples the main sampling and analytic steps, including a continuous flow chamber, with dual Carbotrap preconcentration, a gas chromatographic column, a cold vapor atomic fluorescence spectrometry, and a data logger for signal integration. We compared the operation, performance, and reproducibility between our DAA and the traditional manual analytic method. Its advantages include the ease of operation, the high time resolution and precision (30 min sampling and <5% relative variation), and long-term stability (2 weeks). The DAA can determine DMHg in both the MBL and surface seawater. The estimated detection limits for DMHg with the DAA in the atmosphere and in surface seawater are 10 pg/m3and 0.2 fM, respectively. The successful DAA field measurement in coastal waters indicates that it can help detect the low DMHg concentration in surface seawater, and the time series DMHg data helped our understanding of the DMHg behavior (sources and sinks) and its flux into the MBL. The comparison of DMHg concentration in various oceans also suggests that the coastal region had the lowest averaged DMHg, up to an order of magnitude lower than other ecosystems.