National Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230029, People's Republic of China.
Anal Chem. 2011 Dec 1;83(23):9024-32. doi: 10.1021/ac201838e. Epub 2011 Nov 1.
This paper describes thermal desorption/tunable vacuum-ultraviolet photoionization time-of-flight aerosol mass spectrometry (TD-VUV-TOF-PIAMS) for the real-time analysis of secondary organic aerosols (SOAs) in smog chamber experiments. SOAs are sampled directly from atmospheric pressure and are focused through an aerodynamic lens assembly into the mass spectrometer. Once the particles have entered the source region, they impact on a heater and are vaporized. The nascent vapor is then softly ionized by tunable VUV synchrotron radiation. TD-VUV-TOF-PIAMS was used in conjunction with the smog chamber to study SOA formation from the photooxidation of toluene with hydroxyl radicals. The ionization energies (IEs) of these SOA products are sometimes very different with each other. As the ideal photon source is tunable, its energy can be adjusted for each molecular to be ionized. The mass spectra obtained at different photon energies are then to be useful for molecular identification. Real-time analysis of the mass spectra of SOAs is compared with previous off-line measurements. These results illustrate the potential of TD-VUV-TOF-PIAMS for direct molecular characterization of SOAs in smog chamber experiments.
本文描述了热解吸/可调真空紫外光光电离飞行时间气溶胶质谱（TD-VUV-TOF-PIAMS），用于实时分析烟雾箱实验中的二次有机气溶胶（SOA）。SOA 直接从大气压中采样，并通过气动透镜组件聚焦到质谱仪中。一旦颗粒进入源区，它们就会撞击加热器并蒸发。初生蒸气随后通过可调谐 VUV 同步辐射软电离。TD-VUV-TOF-PIAMS 与烟雾箱一起用于研究甲苯与羟基自由基光氧化形成 SOA。这些 SOA 产物的电离能（IE）有时彼此非常不同。由于理想的光子源是可调谐的，因此可以根据要电离的每个分子来调整其能量。然后，可以使用在不同光子能量下获得的质谱来进行分子鉴定。实时分析 SOA 的质谱与以前的离线测量进行了比较。这些结果说明了 TD-VUV-TOF-PIAMS 在烟雾箱实验中直接对 SOA 进行分子特征分析的潜力。
