Critical evaluation of a seaFAST system for the analysis of trace metals in marine samples.
Critical evaluation of a seaFAST system for the analysis of trace metals in marine samples.
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DOI：
10.1016/j.talanta.2019.01.047
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发表时间：
2019-05
期刊：
影响因子：
6.1
通讯作者：
K. Wuttig;A. Townsend;P. van der Merwe;M. Gault‐Ringold;Thomas C. Holmes;Christina Schallenberg;P. Latour;Manon Tonnard;M. Rijkenberg;D. Lannuzel;A. Bowie
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文献类型：
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作者：
K. Wuttig;A. Townsend;P. van der Merwe;M. Gault‐Ringold;Thomas C. Holmes;Christina Schallenberg;P. Latour;Manon Tonnard;M. Rijkenberg;D. Lannuzel;A. Bowie
采用离线扇形场电感耦合等离子体质谱（SF-ICP-MS）检测的海水预浓缩系统（seaFAST）在四年期间（2015-2018）对南大洋样品的超低痕量元素分析进行了严格评估。市售系统采用两个Nobias PA 1树脂柱进行缓冲液清洗和样品预浓缩，允许盐基质去除，同时提取一系列痕量元素。主要侧重于方法的简单性和实用性，考虑了与海洋学分析相关的一系列实验参数，包括减少空白水平（数周和数年），仪器调节，不同pH值范围内的提取效率（5.8-6.4）和预浓缩系数（约10-70倍）。优化了分析10种重要微量元素的条件（Cd、Co、Cu、Fe、Ga、Mn、Ni、Pb、Ti和Zn），包括在每个单独的分析序列之前对seaFAST单元进行初始预清洁和调节一周;用于提取的受控窄缓冲液pH值为6.20 ± 0.02;样品预浓缩系数为10，（相对）集中的雨水或海冰，40用于典型的海水样本，对于在南大洋等偏远公海采集的海水样品，最高可达67倍。方法精度通过广泛分析一系列海洋标准参考样品（包括SAFe D1（n = 20），D2（n = 3），S（n = 15），GEOTRACES GD（n = 6），GSC（n = 42）和GSP（n = 42）以及NASS-6（n = 6）。海洋样品的测量值被认为是一致的共识值± 6%以内的镉，铜，铁，镍，铅和锌。注意到Co（仅不稳定部分;无UV氧化）、Mn（在其他近期研究中也观察到差异）和Ti（有限参考值）的偏移。Ga目前没有共识值。南大洋样品中的铁和锰也通过流动注射分析方法进行了独立验证（R2= 0.95，n = 244（Fe）和0.92，n = 85（Mn），配对检验，p <0.05）。通过分析社区海水样本以及一系列散装内部海水，评估了四年多的精度（3个来源，每个n~100）和酸空白（n = 250），通常发现在5- 8%范围内，取决于分析物和浓度。此处提供的值代表这些参比样品的最大独立数据集之一，以及目前可用的最完整的GSP和GSC值（共识值尚未发布）。研究了涵盖盐度范围（0-60）的样品，以证明方法的通用性，使用seaFASTNobias PA 1色谱柱观察到极好的回收率（大多数元素>98%，Ga和Ti为70-80%）。举例来说，数据显示了该方法在南大洋印度部分凯尔盖朗高原（HEOBI航行，2016年1月至2月）收集的样本以及2015年夏季在南极洲戴维斯站附近收集的陆地固定冰和盐水中的应用（盐度范围为0至73 g kg−1）。最后，提供了一系列的建议，成功实施seaFAST系统，沿着考虑未来的调查。
A seawater preconcentration system (seaFAST) with offline sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS) detection was critically evaluated for ultra-low trace elemental analysis of Southern Ocean samples over a four-year period (2015–2018). The commercially available system employs two Nobias PA1 resin columns for buffer cleaning and sample preconcentration, allowing salt matrix removal with simultaneous extraction of a range of trace elements. With a primary focus on method simplicity and practicality, a range of experimental parameters relevant to oceanographic analysis were considered, including reduction of blank levels (over weeks and years), instrument conditioning, extraction efficiencies over different pH ranges (5.8–6.4), and preconcentration factors (~10–70 times). Conditions were optimised for the analysis of ten important trace elements (Cd, Co, Cu, Fe, Ga, Mn, Ni, Pb, Ti and Zn) in open ocean seawater samples, and included initial pre-cleaning and conditioning of the seaFASTunit for one week before each separate analytical sequence; a controlled narrow buffer pH of 6.20 ± 0.02 used for extraction; and a sample preconcentration factor of 10 for (relatively) concentrated rainwater or sea ice, 40 for typical seawater samples, and up to 67 times for seawater samples collected in the remote open ocean such as the Southern Ocean.Method accuracy (both short – days to weeks - and long term – months to years) were evaluated through extensive analysis of a range of oceanographic standard reference samples including SAFe D1 (n = 20), D2 (n = 3), S (n = 15), GEOTRACES GD (n = 6), GSC (n = 42) and GSP (n = 42), as well as NASS-6 (n = 6). Measured values for oceanographic samples were found to agree with consensus values to within ± 6% for Cd, Cu, Fe, Ni, Pb and Zn. Offsets were noted for Co (labile fraction only; no UV oxidation), Mn (difference also noted in other recent studies) and Ti (limited reference values). No consensus values currently exist for Ga. Iron and Mn in Southern Ocean samples were also independently verified via flow injection analysis methods (R2= 0.95, n = 244 (Fe) and 0.92, n = 85 (Mn), pairedt-test, p ≪0.05). Precisions over four years were evaluated through analysis of community seawater samples as well as a range of bulk in-house seawaters (3 sources, each n~100) and acid blanks (n = 250), and were typically found to be within 5–8%, depending on analyte and concentration.Values presented here represent one of the largest independent data sets for these reference samples, as well as the most documented comprehensive suite of GSP and GSC values currently available (consensus values have not yet been released). Samples covering a range of salinities (0–60) were investigated to demonstrate method versatility, with excellent recoveries noted using the seaFASTNobias PA1 column (>98% for most elements, with 70–80% for Ga and Ti). By way of example, data is presented showing the application of the method to samples collected on the Kerguelen plateau in the Indian sector of the Southern Ocean (HEOBI voyage, January-February 2016) and in land-fast ice and brine collected near Davis station, Antarctica, in austral summer 2015 (with a salinity range from 0 to 73 g kg−1). Finally, a range of recommendations for successful implementation of a seaFASTsystem are provided, along with considerations for future investigation.