傅里叶变换离子回旋共振质谱（FT-ICR MS）具有超高质量分辨能力和质量精确度，可以实现从分子水平表征复杂有机混合物的组成。FT-ICR MS在研究大气有机气溶胶的分子组成的应用近年来才开始。我们拟利用项目组在气溶胶化学和超高分辨质谱分析方面积累的多年经验研究大气细粒子以及部分燃烧源气溶胶的分子组成，重点着眼于具致癌毒性的有机化合物组，如多环芳烃、含氧多环芳烃、硝基多环芳烃和含氮芳香化合物；或能在肺部细胞中促进活性氧生成的有机化合物组，如醌类化合物和生物碱类。我们将探索合适的离子化方法，结合FT-ICR MS对目标有机化合物组实现分子层次上的解析。项目组将基于对气溶胶主要化学组分及污染源的认识，选取珠三角地区和北京一郊区点具有代表性的大气细粒子样品进行FT-ICR MS分析。本项目将首次获得多套典型中国大气细粒子毒性有机成分的分子组成数据，填补大气细粒子健康效应方面相关知识体系的空白。

Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICRMS) provides unequaled resolving power and mass accuracy among all mass spectrometers. The extreme resolving power and mass accuracy of FT-ICRMS allows characterization of complex organic mixtures at the molecular level through accurate molecular mass determination. This has been plentifully demonstrated in characterizing natural organic matter derived from aqueous environments. Its applications in characterizing atmospheric organic aerosols have only emerged in the past few years. The project team has made the first few exploratory UHRMS studies in probing Chinese aerosols, revealing unprecedented molecular composition information. In this project, we propose to tap into the combined expertise of the project team in aerosol chemistry and ultra-high resolution mass spectrometric analysis to study the molecular composition of PM2.5 collected in the Pearl River Delta region and in a Beijing suburban area and select combustion source aerosols, and the focus will be placed on organic compound groups of either known carcinogenic toxicity, such as polycyclic organic compounds (PAHs), oxygenated PAHs, nitro-PAHs, nitrogen-containing aromatic compounds, or known to be involved in generating reactive oxygen species (ROS) in lung cells, such as quinones, and alkaloids. By seeking suitable modes and methods of ionization methods, the full range of these compound groups in the mass range of 100-1000 will be identified by taking advantage of the unique MS capability of FTICR-MS. Typical PM2.5 samples from the two sampling areas will be selected using our knowledge of major chemical constituents and PM sources. This project will produce unique sets of organic molecular composition data of typical Chinese PM2.5 that are yet unable to be achieved by other analytical techniques. Such information fills in a fundamental knowledge gap in elucidating the health effects by PM2.5.