Custom-made PTFE filters for ultra-clean size-fractionated aerosol sampling for trace metals
Custom-made PTFE filters for ultra-clean size-fractionated aerosol sampling for trace metals
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DOI：
10.1016/j.marchem.2018.09.009
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发表时间：
2018-10
期刊：
影响因子：
3
通讯作者：
K. Sakata;Minako Kurisu;H. Tanimoto;A. Sakaguchi;M. Uematsu;C. Miyamoto;Y. Takahashi
中科院分区：
文献类型：
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作者：
K. Sakata;Minako Kurisu;H. Tanimoto;A. Sakaguchi;M. Uematsu;C. Miyamoto;Y. Takahashi
海洋气溶胶的大气沉积是海洋中溶解的微量金属的重要来源之一。使用萃取实验对尺寸分级气溶胶颗粒中的痕量金属和稳定同位素比率进行分析，有助于了解海洋环境中痕量金属的溶解行为和生物地球化学循环。这些分析需要在清洁的环境中处理样品，且采样过滤器不会污染目标金属。然而，采样过滤器中目标金属的污染程度不够低，无法确定微量金属的溶解度分数（萃取金属/总金属）和稳定同位素比率。在本研究中，我们优化了 Sierra 型级联冲击器的疏水性 PTFE 过滤器的酸洗程序。结果表明，用于级联冲击器上级（= PTFE-ST）的定制 PTFE 过滤器的过滤器毛坯比纤维素过滤器的过滤器毛坯低约 10-1000 倍。此外，使用PTFE-ST还减少了主要离子和水溶性有机碳的过滤空白。除备用阶段外，已在非常短的采样周期内成功测定了尺寸分级（7 级）气溶胶颗粒中的痕量金属浓度。因此，使用污染极小的PTFE过滤器进行气溶胶采样是获取海洋气溶胶颗粒中各种元素的化学和同位素组成的有用方法。
Atmospheric deposition of marine aerosols is one of the important sources of dissolved trace metals in the ocean. Analyses of trace metals and stable isotope ratios in size-fractionated aerosol particles using extraction experiments are useful to understand the dissolution behavior and biogeochemical cycles of trace metals in the marine environment. These analyses require sample treatments in clean environment without contamination of target metals from the sampling filter. However, the contamination of target metals from sampling filter is not low enough to determine the fractional solubility (extractive metal/total metal) and the stable isotope ratio of trace metals. In this study, we optimized the acid-washing procedure of hydrophobic PTFE filter for the Sierra-type cascade impactor. The results showed that the filter blanks of the custom-made PTFE filters used for the upper stages (= PTFE-ST) in the cascade impactor were about 10–1000 times lower than those of cellulose filters. In addition, the filter blanks of major ions and water-soluble organic carbon were also decreased by using PTFE-ST. Trace metal concentrations in size-fractionated (7 fractions) aerosol particles with very short sampling periods have been successfully determined except for the backup stage. Thus, aerosol sampling with PTFE filter with only a tiny contamination is a useful method to obtain chemical and isotopic compositions of various elements in marine aerosol particles.