STTR Phase II: Aerosol Mass Spectrometer for Size and Composition Analysis of Sub-Micron Particles

这一小企业技术转让第二阶段项目将开发一种气溶胶取样仪器，该仪器可真实的实时提供亚微米级颗粒的尺寸和化学成分信息。该仪器将应用于目前无法获得商业仪器的空气中颗粒物分析。该设备将成熟的气溶胶采样和粒度分离技术与独特的热线颗粒汽化/质谱检测方案相结合。该仪器与目前利用高功率激光进行颗粒蒸发的研究系统相比不太复杂，因此将显著降低颗粒分析的成本。粒子质谱仪结合了空气动力学气溶胶采样入口和充电系统，该系统产生带电粒子束，其大小由其与电场的相互作用决定。选定质量的光束撞击热线，粒子在热线处蒸发并凝结。用分子飞行时间（TOP）质谱仪分析所得离子。第一阶段的工作已经成功地耦合粒子质谱仪与热线汽化技术，使用四极质谱检测。最初的工作已经证明了化学成分检测的范围内的液体和固体盐颗粒的单个粒子的直径下降到0.1 1 lm。在第二阶段工作中，探测极限将扩展到-0.03 1 lm直径。 该仪器将用于基本的大气气溶胶研究，并作为燃烧源（燃煤发电厂以及商用飞机和汽车的废气）微粒排放的在线真实的实时监测器。

This Small Business Technology Transfer Phase II project will develop an aerosol sampling instrument that yields both size and chemical composition information in real time for sub-micron sized particles. The instrument will have application to airborne particle analysis where commercial instrumentation is currently unavailable. The device combines proven technology for aerosol sampling and size separation with a unique hot wire particle vaporization/mass spectrometric detection scheme. This instrument is less complex compared to current research systems utilizing high power lasers for particle vaporization and, hence, will provide a significant cost reduction for particle analysis. The particle mass spectrometer combines an aerodynamic aerosol sampling inlet and charging system which generates a beam of charged particles whose size is determined by its interaction with electric fields. The mass selected beam impacts a hot wire where the particles vaporize and ionize. The resulting ions are analyzed with a molecular time of flight (TOP) mass spectrometer. The Phase I work has successfully coupled the particle mass spectrometer with the hot wire vaporization technique using quadrupole mass spectrometric detection. The initial work has demonstrated chemical composition detection for single particles for a range of liquid and solid salt particles down to 0.1 1lm diameter. The detection limit will be extended in the Phase II work to -0.03 1lm diameter. The instrument will be useful for basic atmospheric aerosol research and as a real time monitor for on-line particulate emissions from combustion sources (coal-fired power plants, and exhaust from commercial aircraft and automobiles).