Development and application of a comprehensive thermal desorption/photoionisation mass spectrometry instrument for the determination of the nature of the carbonaceous fraction and the oligomeric/polymeric content of ambient participate matter

更好地了解对流层气溶胶中含碳物质的化学组成对于气候和健康研究非常重要。最近的研究表明，除了挥发性和半挥发性有机物（OC）以及所谓的元素碳组分（EC），城市气溶胶中还存在聚合物（如腐殖类物质）和高极性多官能化合物（如糖衍生物）。这对于含碳二次气溶胶颗粒（SOA）也是特别有效的。气溶胶中的低挥发性有机组分至今难以分析。应用创新的热方法，通过释放过滤器上采样的颗粒物（PM）的含碳部分，并采用一系列温度步骤，从约100 ℃到约100 ℃，100至850 °C（通过解吸、热解和氧化）使得能够检测化学上不同的键合碳作为非特异性总和参数。在拟议的项目中，将开发一种新的分析技术，通过该技术，将用于释放碳分子或热解产物的热分析方法与新的光电离质谱仪（软单光子和多光子电离，SPI和REMPI）联用。通过这样做，可以对进化产物进行直接化学分析。在高达340°C的温度范围内成功进行的初步可行性研究表明，PM的分子成分，例如多环芳烃以及聚合气溶胶成分的热解产物是可检测的。开发和优化后的新技术，除了改进表征的低聚物和聚合物部分的碳质PM的人为和生物的SOA部分的区别将尝试。

A better understanding of the chemical composition of carbonaceous material from tropospheric aerosol is very important with respect to climatic and health research. Recent investigations revealed that in addition to volatile and semivolatile organic species (OC) as well as so called elementary carbon fractions (EC) also polymeric (e.g. humic like substances) and highly polar, polyfunctional compounds (e.g. sugar derivatives) are present in urban aerosol. This is especially valid also for carbonaceous secondary aerosol particles (SOA). Low volatile organic constituents of aerosol are hardly accessible analytically up to now. Applying innovative thermal methods for determination of OC and EC fractions by releasing the carbonaceous portion of particulate matter (PM) sampled on filter with a succession of temperature steps from approx. 100 to 850 °C (by desorption, pyrolysis, and oxidation) enables detection of chemically different bonded carbon as non-specific sum parameters. In the proposed project a novel analytical technique will be developed, by which the thermal analytical method for releasing carbonaceous molecules or pyrolysis products is hyphenated with a new photo ionisation mass spectrometer (soft single and multi photon ionisation, SPI and REMPI). By doing so, a direct chemical analysis of the evolved products is possible. A successful preliminary feasibility study in the temperature range up to 340°C showed, that molecular components of PM, e.g. polycyclic aromatic hydrocarbons as well as pyrolysis products of polymeric aerosol constituents are detectable. After development and optimisation of the novel technique, in addition to an improved characterisation of oligomeric and polymeric fractions of carbonaceous PM distinction of anthropogenic and biogenic portions of SOA will be attempted.