State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
J Environ Sci (China). 2009;21(12):1658-66. doi: 10.1016/s1001-0742(08)62470-5.
The organic matter in tropospheric aerosol plays an important role in atmospheric physical and chemical processes. The bulk of organic matter, representing a significant proportion of the total suspended particulate (TSP) mass, is bound to polymeric material whose structure and properties are largely unknown. Here we used thermodesorption gas chromatography/mass spectrometry (Td-GC/MS) to study organic compounds of low molecular mass and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) to characterize the chemical structure of macromolecules in TSP samples collected in different seasons from different sites in Guangzhou. n-Alkanes, fatty acids and nitriles were the predominant compounds in the thermodesorption products, whereas aromatics, fatty acids, nitriles and n-alkanes/alkenes were the major compounds in the pyrolysates. The results indicated that aromatics were main units in macromolecules. The fatty acids and nitriles formed from carboxylic ammonium salts were detected in both thermodesorption products and pyrolysates at a certain concentration, indicating the importance of these compounds in TSP formation. The TSP source mainly determined the occurrence of compounds in samples from urban, suburban and forest sites, whereas the TSP source and formation process maybe controlled the seasonal variation in compounds detected. High levels of nitriles in summer samples from suburban and forest sites coincide with the release of ammonium from the land and of fatty acids from vegetation at these sites.
大气气溶胶中的有机物在大气物理和化学过程中起着重要作用。大部分有机物代表了总悬浮颗粒物（TSP）质量的很大一部分，与聚合物材料结合在一起，其结构和性质在很大程度上是未知的。在这里，我们使用热解吸气相色谱/质谱法（Td-GC/MS）研究低分子量的有机化合物，并使用热解气相色谱/质谱法（Py-GC/MS）来表征 TSP 样品中大分子的化学结构，这些样品是在不同季节从广州不同地点收集的。正烷烃、脂肪酸和腈是热解产物中的主要化合物，而芳烃、脂肪酸、腈和正烷烃/烯烃是热解产物中的主要化合物。结果表明，芳烃是大分子的主要单元。从羧酸铵盐形成的脂肪酸和腈在热解产物和热解产物中都以一定的浓度存在，这表明这些化合物在 TSP 形成中很重要。TSP 源主要决定了来自城市、郊区和森林地区样品中化合物的存在，而 TSP 源和形成过程可能控制了所检测化合物的季节性变化。郊区和森林地区夏季样品中腈的含量较高，这与这些地区土地中铵的释放以及植被中脂肪酸的释放相吻合。
