Chemical Structural Features of Humic-like Substances (HULIS) in Urban Atmospheric Aerosols Collected from Central Tokyo with Special Reference to Nuclear Magnetic Resonance Spectra
Chemical Structural Features of Humic-like Substances (HULIS) in Urban Atmospheric Aerosols Collected from Central Tokyo with Special Reference to Nuclear Magnetic Resonance Spectra
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DOI：
10.5572/ajae.2018.12.2.153
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发表时间：
2018-06
影响因子：
1.5
通讯作者：
Naoya Katsumi;Shuhei Miyake;H. Okochi
中科院分区：
文献类型：
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作者：
Naoya Katsumi;Shuhei Miyake;H. Okochi
我们测量了城市大气气溶胶中由二乙氨基乙基 (DEAE) 和亲水亲油平衡 (HLB) 树脂分离的类腐殖质物质 (HULIS) 的 1H 和 13C 核磁共振 (NMR) 谱，以表征其化学结构。与HLB树脂分离的HULIS相比，DEAE树脂分离的HULIS具有较高的芳香族质子含量和较低的脂肪族质子含量，而与含氧脂肪族碳原子结合的质子含量相似。这些结果与 13C NMR 分析的结果一致，表明疏水性组分更选择性地吸附到 HLB 上，而 DEAE 树脂选择性地保留芳香族羧酸。此外，我们证明了 HULIS 的化学结构特征在春季和夏季样品之间存在显着差异，并且这些差异反映了它们的不同来源。研究发现，春季 HULIS 的估计浓度受到车辆排放和花粉扩散的调节，而夏季 HULIS 的行为与光化学氧化剂和二氧化氮浓度相似。夏季样品中脂肪族质子的比例高于春季样品，而夏季样品中芳香族质子的比例低于春季样品。化学结构的这些季节性变化也可能涉及它们在大气中的功能表达。
We measured 1H and 13C nuclear magnetic resonance (NMR) spectra of Humic-like substances (HULIS) in urban atmospheric aerosols isolated by diethylaminoethyl (DEAE) and hydrophilic-lipophilic balance (HLB) resin to characterize their chemical structure. HULIS isolated by DEAE resin were characterized by relatively high contents of aromatic protons and relatively low contents of aliphatic protons in comparison with HULIS isolated by HLB resin, while the contents of protons bound to oxygenated aliphatic carbon atoms were similar. These results were consistent with the results of the 13C NMR analysis and indicate that hydrophobic components were more selectively adsorbed onto HLB, while DEAE resins selectively retained aromatic carboxylic acids. Furthermore, we demonstrated that the chemical structural features of HULIS were significantly different between spring and summer samples and that these disparities were reflective of their different sources. The estimated concentrations of HULIS in spring were found to be regulated by vehicle emissions and pollen dispersion, while the behavior of HULIS in summer was similar to photochemical oxidant and nitrogen dioxide concentrations. The proportion of aliphatic protons for summer samples was higher than that for spring samples, while the proportion of aromatic protons for summer samples was lower than that for spring samples. These seasonal changes of the chemical structure may also involve in their functional expression in the atmosphere.