A molecular-level approach for characterizing water-insoluble components of ambient organic aerosol particulates using ultrahigh-resolution mass spectrometry
A molecular-level approach for characterizing water-insoluble components of ambient organic aerosol particulates using ultrahigh-resolution mass spectrometry
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DOI：
10.5194/acp-14-10299-2014
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发表时间：
2014-09
影响因子：
6.3
通讯作者：
A. S. Willoughby;A. Wozniak;P. Hatcher
中科院分区：
文献类型：
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作者：
A. S. Willoughby;A. Wozniak;P. Hatcher
抽象的。大气中有机气溶胶的化学成分受到人类排放的强烈影响。这些化学物质对环境、人类健康和气候变化的影响取决于这些化学物质的分子性质。有机气溶胶样品的复杂性限制了研究化学成分的能力，从而限制了相关性质及其影响。许多研究都涉及有机气溶胶的水溶部分，并在确定存在的数千种化合物的特定分子式方面取得了很大成功。然而，对水不溶部分的关注很少，因为它可能包含人类活动排放的大部分化石物质。在这里，我们比较了在受自然和人为排放源影响的农村地区收集的环境气溶胶样本的水提取物和有机溶剂提取物(吡啶和乙腈)中存在的有机气溶胶。利用质子核磁共振波谱建立了一种半定量的方法，用于测定吡啶提取的有机物与水提取的有机物的量相当。电喷雾电离傅里叶变换离子回旋共振质谱图表明，与水或乙腈相比，吡啶提取的有机物在分子上是独特的，后者提取化学上相似的有机物成分。吡啶所特有的分子式的极性较低，但更多的是脂肪族，并揭示了含有硫的分子式是不溶性气溶胶有机物的重要组成部分。
Abstract. The chemical composition of organic aerosols in the atmosphere is strongly influenced by human emissions. The effect these have on the environment, human health, and climate change is determined by the molecular nature of these chemical species. The complexity of organic aerosol samples limits the ability to study the chemical composition, and therefore the associated properties and the impacts they have. Many studies have addressed the water-soluble fraction of organic aerosols and have had much success in identifying specific molecular formulas for thousands of compounds present. However, little attention is given to the water-insoluble portion, which can contain most of the fossil material that is emitted through human activity. Here we compare the organic aerosols present in water extracts and organic solvent extracts (pyridine and acetonitrile) of an ambient aerosol sample collected in a rural location that is impacted by natural and anthropogenic emission sources. A semiquantitative method was developed using proton nuclear magnetic resonance spectroscopy to determine that the amount of organic matter extracted by pyridine is comparable to that of water. Electrospray ionization Fourier transform ion cyclotron resonance mass spectra show that pyridine extracts a molecularly unique fraction of organic matter compared to water or acetonitrile, which extract chemically similar organic matter components. The molecular formulas unique to pyridine were less polar, more aliphatic, and reveal formulas containing sulfur to be an important component of insoluble aerosol organic matter.