Automated, high frequency, on-line dimethyl sulfide measurements in natural waters using a novel "microslug" gas-liquid segmented flow method with chemiluminescence detection.
Automated, high frequency, on-line dimethyl sulfide measurements in natural waters using a novel "microslug" gas-liquid segmented flow method with chemiluminescence detection.
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DOI：
10.1016/j.talanta.2020.121595
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发表时间：
2021-01
期刊：
影响因子：
6.1
通讯作者：
Geng Leng;Chao-Feng Jin;T. Bell;S. Ussher;P. Worsfold;Wei-Yi Li
中科院分区：
文献类型：
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作者：
Geng Leng;Chao-Feng Jin;T. Bell;S. Ussher;P. Worsfold;Wei-Yi Li
二甲硫醚（DMS）是表层海水中主要的生物挥发性硫化合物。具有高时间和空间分辨率的高质量 DMS 数据对于了解还原硫生物地球化学是理想的。在这里，我们提出了一种基于“微段塞”气液分段流动化学发光（MSSF-CL）的新型方法，用于连续原位测量天然水中的 DMS。将样品收集到流动罐中，并使用变向盘旋流将 DMS 从水相转移到气相，其中散布有微量液体和气体段塞。分离的 DMS 在反应池中与臭氧反应，用于 CL 检测。分析过程是自动化的，样品通量为 6.6 h−1。与常用的鼓泡方法相比，使用 MSSF 进行 DMS 分离更有效，并且更容易与 CL 检测集成。研究了所提出方法的关键参数。该方法的线性范围为 0.05–500 nM (R2= 0.9984)，检测限 (3 x S/N) 为 0.015 nM，与常用的气相色谱 (GC) 方法相当，并且足够灵敏，足以在典型水生环境中进行直接 DMS 测量。通过在天然水样（河流、湖泊、水库和池塘）中添加不同浓度的 DMS（10、20 和 50 nM）来评估重现性和回收率，相对标准偏差 (RSD) ≤1.75% (n = 5)，回收率为 94.4–107.8%。该全自动系统无需试剂、易于组装、使用简单、便于携带（重量约 5.1 千克），并且可以在现场进行数小时的无人值守操作。该仪器可以为天然水体提供高质量的 DMS 数据，环境相关的时间分辨率约为 9 分钟。
Dimethyl sulfide (DMS) is the major biogenic volatile sulfur compound in surface seawater. Good quality DMS data with high temporal and spatial resolution are desirable for understanding reduced sulfur biogeochemistry. Here we present a fully automated and novel “microslug” gas-liquid segmented flow-chemiluminescence (MSSF-CL) based method for the continuousin-situmeasurement of DMS in natural waters. Samples were collected into a flow tank and DMS transferred from the aqueous phase to the gas phase using a vario-directional coiled flow, in which microvolume liquid and gas slugs were interspersed. The separated DMS was reacted with ozone in a reaction cell for CL detection. The analytical process was automated, with a sample throughput of 6.6 h−1. Using MSSF for DMS separation was more effective and easily integrated with CL detection compared with the commonly used bubbling approach. Key parameters of the proposed method were investigated. The linear range for the method was 0.05–500 nM (R2= 0.9984) and the limit of detection (3 x S/N) was 0.015 nM, which is comparable to the commonly used gas chromatography (GC) method and sensitive enough for direct DMS measurement in typical aquatic environments. Reproducibility and recovery were assessed by spiking natural water samples (river, lake, reservoir and pond) with different concentrations of DMS (10, 20 and 50 nM), giving relative standard deviations (RSDs) ≤1.75% (n = 5) and recoveries of 94.4–107.8%. This fully automated system is reagent free, easy to assemble, simple to use, portable (weight ~5.1 kg) and can be left in the field for several hours of unattended operation. The instrumentation can provide high quality DMS data for natural waters with an environmentally relevant temporal resolution of ~9 min.