By taking advantage of recent advances in High-Resolution Atmospheric Pressure intake Time of Flight (APi–TOF) Mass Spectrometry (MS), the chemical analysis of naturally charged flame-generated soot nuclei and precursors is explored using a well-characterized dilution sampling approach. Measurements were performed for mass-to-charge ratio up to 2000 Thomson, bridging the gap between the gas phase and the particle phase. The flame products were sampled at several heights above the burner (HAB) in the soot inception zone of the flame, quickly diluted in nitrogen and directly transported to the APi–TOF inlet. The investigated sooting premixed flame has been the object of multiple studies over the years and the present results complement existing literature data. The analyses of flame products naturally carrying charge of either polarity revealed the chemical and polarity-dependent complexity of the nucleation and chemi-ionization processes. The measured high-resolution mass spectra include peaks attributed to (hydrocarbon) molecules/clusters containing oxygen and nitrogen atoms and suggest that collision charging of flame pyrolysis products likely involves protonation/deprotonation of neutral materials. Results clearly show the change of the overall composition of the charged flame products at different HABs. Patterns in the mass spectra under different conditions were investigated to discriminate between collision charging, chemical reaction and physical clustering (i.e., coagulation and condensation) growth mechanisms. A comparison of the results with those obtained with High-resolution Differential Mobility Analysis (HR-DMA) in a recent study allowed for a more quantitative determination of the ion number concentrations.

通过利用高分辨率大气压进气飞行时间（APi–TOF）质谱（MS）的最新进展，使用特征明确的稀释采样方法探索了天然带电火焰生成的烟尘核和前体的化学分析。 。进行了高达2000 Thomson的质荷比测量，弥合了气相和颗粒相之间的间隙。在火焰的烟灰起始区中，在燃烧器（HAB）上方几个高度对火焰产物进行采样，然后在氮气中迅速稀释并直接运输到APi–TOF入口。多年来，研究的烟灰预混火焰一直是多项研究的目标，目前的结果补充了现有的文献数据。对天然带有两种极性电荷的火焰产物的分析揭示了成核和化学电离过程的化学和极性相关的复杂性。测得的高分辨率质谱图包括归因于含有氧和氮原子的（烃）分子/团簇的峰，这表明火焰热解产物的碰撞带电可能涉及中性物质的质子化/去质子化。结果清楚地表明在不同的HAB处带电火焰产物的整体组成发生了变化。研究了在不同条件下的质谱图，以区分碰撞电荷，化学反应和物理团簇（即凝结和凝结）的生长机理。