Two-Dimensional Offline Chromatographic Fractionation for the Characterization of Humic-Like Substances in Atmospheric Aerosol Particles.
Two-Dimensional Offline Chromatographic Fractionation for the Characterization of Humic-Like Substances in Atmospheric Aerosol Particles.
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DOI：
10.1021/acs.est.7b00077
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发表时间：
2017-04
影响因子：
11.4
通讯作者：
T. Spranger;D. van Pinxteren;H. Herrmann
中科院分区：
文献类型：
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作者：
T. Spranger;D. van Pinxteren;H. Herrmann
大气颗粒物中的有机碳包括很大一部分色谱法无法解析的化合物，通常被称为类腐殖酸物质（HULIS），它们影响颗粒物的性质并影响气候，人类健康和生态系统。为了更好地了解其组成，提出了一种结合尺寸排阻（SEC）和反相液相色谱（RP-HPLC）的二维（2D）离线方法，该方法使用新的加标梯度曲线。它将HULIS分离成55个不同大小和极性的馏分，分子量和辛醇/水分配系数（log P）的估计范围分别为160-900 g/mol和0.2-3.3。HULIS在2D尺寸与极性空间内的分布用254 nm处的紫外吸收热图来说明。它被发现强烈不同，在一个小的例子集的样本，从莱比锡，德国附近的背景网站。在冬季，最强的信号获得的最大的分子（>520 g/mol）与低极性（log P <$1.9），而在夏季，较小的（225-330 g/mol）和更极性（log P <$0.55）的分子占主导地位。该方法揭示了这样的差异，在HULIS组成在一个更详细的方式比以前可能的，因此可以帮助更好地阐明来源的HULIS在不同的季节或在不同的网站。分析Suwannee河富里酸作为一个共同的HULIS替代品显示了类似的极性范围，但大小明显大于大气HULIS。
Organic carbon in atmospheric particles comprises a large fraction of chromatographically unresolved compounds, often referred to as humic-like substances (HULIS), which influence particle properties and impact climate, human health, and ecosystems. To better understand its composition, a two-dimensional (2D) offline method combining size-exclusion (SEC) and reversed-phase liquid chromatography (RP-HPLC) using a new spiked gradient profile is presented. It separates HULIS into 55 fractions of different size and polarity, with estimated ranges of molecular weight and octanol/water partitioning coefficient (log P) from 160-900 g/mol and 0.2-3.3, respectively. The distribution of HULIS within the 2D size versus polarity space is illustrated with heat maps of ultraviolet absorption at 254 nm. It is found to strongly differ in a small example set of samples from a background site near Leipzig, Germany. In winter, the most intense signals were obtained for the largest molecules (>520 g/mol) with low polarity (log P ∼ 1.9), whereas in summer, smaller (225-330 g/mol) and more polar (log P ∼ 0.55) molecules dominate. The method reveals such differences in HULIS composition in a more detailed manner than previously possible and can therefore help to better elucidate the sources of HULIS in different seasons or at different sites. Analyzing Suwannee river fulvic acid as a common HULIS surrogate shows a similar polarity range, but the sizes are clearly larger than those of atmospheric HULIS.