Hyphenation of fast gas chromatography to photo-ionisation mass spectrometry for comprehensive analysis of climate and health-relevant organic aerosol components from dynamic combustion processes

众所周知，有机气溶胶的成分对人类健康和气候有复杂的影响。燃烧过程动态变化的研究，如原木燃烧或内燃机在不同负荷下的动态变化，需要适当的时间分辨率测量技术，以跟踪复杂有机排放的定性和定量变化。单光子（SPI）和共振增强多光子电离（REMPI）作为软电离技术与飞行时间质谱（TOFMS）相结合，满足了这些要求。然而，仅根据分子质量不能对化合物进行明确的鉴定。采用新型peltier调制器的快速气相色谱法与SPI/REMPI-TOFMS联用可以克服这一问题，分离出等压物质，而保留时间相同但分子质量不同的化合物在质谱上通过不同的峰进行分离。因此，在动态燃烧过程中，单挥发性到半挥发性化合物可以用足够的时间分辨率进行分析。重点将放在烷基化多环芳烃（PAH）和酚类物质上，这两种物质都可以通过SPI-和REMPI-TOFMS进行低检测限的分析。烷基化多环芳烃主要由化石燃料的燃烧过程排放，最近成为多环芳烃研究的中心，因为研究表明它们可以表现出与其未取代的基本结构显著不同的毒理学特性。已知酚类物质主要由生物质燃烧排放，并被讨论为减轻燃烧气溶胶中其他化合物的毒理学效应。除了对排放物进行毒理学评估外，这些数据对于预测环境空气中可能的转化过程，例如臭氧形成潜力或二次有机气溶胶的形成，也很有价值。最后，Fast-GC-SPI/REMPI装置可以进一步用于热光学碳分析仪的附加连接，以研究颗粒结合的有机物种，覆盖有机气溶胶排放的整个挥发范围。

Components of organic aerosol are known to have complex impacts on human health and climate. The investigation of dynamic changes in combustion processes, such as in log wood combustion or internal combustion engines at different loads, requires measurement techniques of appropriate time resolution to follow qualitative and quantitative changes of complex organic emissions. Single-photon (SPI) and resonance-enhanced multi-photon ionisation (REMPI) as soft ionisation techniques combined with time-of-flight mass spectrometry (TOFMS) fulfil these requirements. However, solely based on molecular mass no definite identifications of compounds can be carried out. The hyphenation of fast gas chromatography with a novel Peltier-modulator to SPI/REMPI-TOFMS can overcome this issue and separate isobaric species, while compounds of equal retention time but different molecular mass are separated by different peaks in the mass spectra. Hence, single volatile to semi-volatile compounds can be analysed with sufficient time resolution during dynamic combustion processes. The focus will be on alkylated polycyclic aromatic hydrocarbons (PAH) and phenolic species, which both can be analysed by SPI- and REMPI-TOFMS with low limits of detection. Alkylated PAHs, which are mainly emitted by combustion processes using fossil fuels, have recently moved towards the centre stage of PAH research, because it has been shown that they can exhibit significantly different toxicological properties than their unsubstituted basic structures. Phenolic species are known to be emitted by mainly biomass combustion and are discussed as mitigating toxicological effects of other compounds of the combustion aerosol. In addition to the toxicological assessment of emissions, the data can be valuable to predict possible conversion processes in ambient air, e.g. ozone formation potential or the formation of secondary organic aerosol. Finally, the Fast-GC-SPI/REMPI setup can be further utilised in an additional hyphenation to a thermal-optical carbon analyser to investigate particle-bound organic species , covering the full volatility range of organic aerosol emission.