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Advances and Applications of Mass Spectral Techniques for the Characterization of Atmospheric Aerosol Particles.

机译：质谱技术在大气气溶胶粒子表征中的进展与应用。

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摘要

Aerosol particles are ubiquitous in the atmosphere and induce significant impacts on human health and climate that depend on their physical and chemical properties, such as size, composition, and mixing state (chemical associations). Measurements of aerosol composition at the single-particle level are necessary to better understand these effects. Aerosol time-of-flight mass spectrometry (ATOFMS) is able to monitor the size and chemical composition of individual particles in real time. In this doctoral research, ATOFMS analysis was extended to identify new mass spectral markers and improve the potential for quantitative measurements. Development of novel instrumentation was also undertaken.;Ion markers indicative of organosulfate compounds were identified in ATOFMS mass spectra collected in Atlanta, GA. In this study, the mixing state and temporal behavior of particulate organosulfate compounds were observed for the first time. Organosulfates were overwhelmingly detected in carbonaceous submicron particles and the temporal trends indicated that they likely formed by the daytime oxidation of isoprene followed by aqueous reaction with sulfate overnight. These results highlight the roles of mixing state and multi-phase reactivity on the formation of secondary organic aerosols.;ATOFMS measurements of thermally-conditioned aerosol residuals obtained during the 2005 Study of Organic Aerosols in Riverside, CA were analyzed to determine the impacts of atmospheric aging on the laser desorption/ionization process. Coatings of secondary species suppressed the ionization efficiency, thereby impacting the mass spectral peak areas; however, a novel analysis method was found to correct these artifacts and produced strong agreement with collocated quantitative instrumentation. This new analysis technique was then applied to investigate the mixing-state dependence of aerosol volatility observed in Riverside. It was observed that particulate nitrate evaporated at different temperatures from different particle types (e.g., organic vs. biomass burning), which may influence the regional transport of nitrate species.;ATOFMS provides important insights into size-resolved particle sources; however it heavily fragments most organic species, resulting in loss of the molecular information. Therefore, a novel chemical ionization mass spectrometer was developed to better characterize the molecular organic aerosol constituents. In particular, an ion funnel was incorporated into a home-built proton-transfer-reaction mass spectrometer. Initial characterization studies and ion simulations indicated that the ion funnel can provide high-efficiency ion transfer from the ionization region to the mass spectrometer. These results demonstrate the potential for this instrument to ultimately achieve highly sensitive analyses of organic aerosols.
机译：气溶胶颗粒在大气中无处不在，并根据其物理和化学特性（例如大小，组成和混合状态（化学缔合））对人体健康和气候产生重大影响。为了更好地理解这些影响，必须对单颗粒水平的气溶胶成分进行测量。气溶胶飞行时间质谱（ATOFMS）能够实时监控单个颗粒的大小和化学成分。在这项博士研究中，ATOFMS分析得到了扩展，以识别新的质谱标记并提高定量测量的潜力。还进行了新型仪器的开发。；在佐治亚州亚特兰大市收集的ATOFMS质谱图中鉴定了指示有机硫酸盐化合物的离子标记。在这项研究中，第一次观察到了颗粒状有机硫酸盐化合物的混合状态和时间行为。在碳质亚微米颗粒中绝大多数检测到有机硫酸盐，其时间趋势表明，它们很可能是由白天异戊二烯的氧化，然后与硫酸盐的水溶液反应过夜而形成的。这些结果凸显了混合状态和多相反应性在二次有机气溶胶形成中的作用。分析了2005年在加利福尼亚州里弗赛德进行的有机气溶胶研究期间获得的热调节气溶胶残留量的ATOFMS测量结果，以确定大气的影响激光解吸/电离过程的老化。次要物种的涂层抑制了电离效率，从而影响了质谱峰面积。然而，发现了一种新颖的分析方法来纠正这些伪影，并与并置的定量仪器产生了强烈的一致性。然后将这种新的分析技术用于研究在河滨观测到的气溶胶挥发性的混合态依赖性。观察到硝酸盐颗粒在不同的温度下从不同的颗粒类型蒸发（例如，有机燃烧与生物质燃烧），这可能会影响硝酸盐物种的区域迁移。但是，它会严重破坏大多数有机物种，导致分子信息丢失。因此，开发了一种新型化学电离质谱仪，以更好地表征分子有机气溶胶成分。特别地，将离子漏斗结合到自制的质子转移反应质谱仪中。初步的表征研究和离子模拟表明，离子漏斗可以提供从电离区域到质谱仪的高效离子转移。这些结果表明该仪器有潜力最终实现对有机气溶胶的高灵敏度分析。

著录项

  • 作者

    Hatch, Lindsay Erighn.;

  • 作者单位

    University of California, San Diego.;

  • 授予单位 University of California, San Diego.;
  • 学科 Chemistry.;Atmospheric chemistry.;Analytical chemistry.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 197 p.
  • 总页数 197
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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