Aromatic formulas in ambient PM2.5 samples from Hong Kong determined using FT-ICR ultrahigh-resolution mass spectrometry
Aromatic formulas in ambient PM2.5 samples from Hong Kong determined using FT-ICR ultrahigh-resolution mass spectrometry
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使用 FT-ICR 超高分辨率质谱法测定香港环境 PM2.5 样品中的芳香族分子式
DOI：
10.1007/s00216-018-1239-8
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发表时间：
2018-09-01
影响因子：
4.3
通讯作者：
Yu, Jian Zhen
中科院分区：
文献类型：
--
作者：
Kuang, Bin-Yu;Yeung, Hoi Sze;Yu, Jian Zhen
许多芳族化合物（例如，在大气气溶胶中发现的多环芳烃（PAH）是有毒的，并且以未取代和取代的形式存在。以前的研究主要集中在未取代的多环芳烃的调查，离开取代的化合物在很大程度上未被表征。本研究的重点是使用超高分辨率质谱检测环境气溶胶样品中未取代和取代的芳烃。采用傅里叶变换离子回旋共振质谱（FT-ICR-MS）结合大气压光电离（APPI）或电喷雾电离（ESI）对香港路边、市区和郊区的气溶胶样品进行了表征。在APPI+模式中，166个芳族CH式（即，仅含有C和H且双键当量（DBE）为4或更高的分子式）通过基于精确m/z测定的分子式计算来确定。在确定的芳香CH分子式中，有141个可能是烷基化的单环芳烃（MAH）或PAH分子式，占芳香CH+分子式总强度的45%以上。APPI+和ESI+在检测硝基芳烃（即，CHO 2N 1公式和DBE ≥ 5）。这两种电离模式提供了互补的分子式覆盖范围，由APPI+确定的分子式延伸到更高的DBE，而由ESI+确定的分子式覆盖更高的碳数。烷基化硝基苯化合物是硝基芳烃中含量最多的化合物，它们与烷基化硝基多环芳烃一起占芳香族CHO 2N+分子式总强度的80%以上，表明这些化合物在真实的气溶胶样品中的重要性。芳香CHN+和CHO+公式也确定，确认大气中存在的一些以前报道的O-和N-含芳香族化合物，并揭示新的可能的公式。本研究中芳香族有机分子式的确定为今后有害芳香族化合物的定量分析提供了有益的指导。未来的工作需要确定的丰度和研究的毒性烷基化的MAH和多环芳烃以外的16个美国环保局的优先多环芳烃化合物。图形摘要。
Many aromatic compounds (e.g., polycyclic aromatic hydrocarbons (PAHs)) found in atmospheric aerosols are toxic and exist in both unsubstituted and substituted forms. Previous studies have mainly concentrated on investigating unsubstituted PAHs, leaving the substituted compounds largely uncharacterized. This study focuses on detection of both unsubstituted and substituted aromatics in ambient aerosol samples using ultrahigh-resolution mass spectrometry. Aerosol samples collected from roadside, urban, and suburban sites in Hong Kong were characterized by Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) coupled with atmospheric pressure photoionization (APPI) or electrospray ionization (ESI). In the APPI+ mode, 166 aromatic CH formulas (i.e., formulas containing C and H only and with a double bond equivalent (DBE) of 4 or higher) were determined through molecular formula calculations based on an accurate m/z determination. Among the determined aromatic CH formulas, 141 are possible alkylated monocyclic aromatic hydrocarbon (MAH) or PAH formulas, and account for ≥ 45% of the total intensity by aromatic CH+ formulas. Both APPI+ and ESI+ are effective in detecting nitroaromatics (i.e., CHO2N1formulas and DBE ≥ 5). The two ionization modes provide complementary formula coverage, with formulas determined by APPI+ extending to higher DBE and those by ESI+ covering higher carbon numbers. Alkylated nitrobenzene compounds are the most abundant among nitroaromatics, and they, together with alkylated nitro-PAHs, account for > 80% of the total intensity of aromatic CHO2N+ formulas, indicating the importance of these compounds in real aerosol samples. Aromatic CHN+ and CHO+ formulas are also determined, confirming the atmospheric presence of some previously reported O- and N-containing aromatic compounds and revealing new possible formulas. The determination of aromatic organic formulas in this study provides useful guidance for future quantitative analysis of hazardous aromatic compounds. Future work is needed to determine the abundance and to study the toxicity of alkylated MAHs and PAHs outside the 16 US EPA priority PAH compounds. Graphical abstract.