Linking Bulk and Single-Particle Composition of Atmospheric PM: A Cross-Platform Approach for the Analysis of Alkylated Polycyclic Aromatic Hydrocarbons Using GC×GC-MS and SPMS

• Applicant: Dr. Barbara Giocastro
• Subject Area: Analytical Chemistry
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 566503831

This project aims to combine comprehensive two-dimensional gas chromatography- mass spectrometry (GC×GC-MS) methods with single particle mass spectrometry (SPMS) to advance the molecular speciation of atmospheric particulate matter (PM). By integrating these methods, the project establishes a powerful cross-platform system for the detailed identification and quantification of organic pollutants in PM, addressing both bulk and single-particle level. Through the fine-tuning of experimental conditions and setups, the project aims to establish correlations between the bulk chemical profile of atmospheric PM and the detailed chemical composition of individual particles, thereby offering an enhanced molecular-level understanding of pollutant distribution, source identification, and potential health impacts. This innovative approach will be tested and utilized for the determination of polycyclic aromatic hydrocarbons (PAHs), with particular focus on their alkylated (Alkyl-PAHs) derivatives. Alkyl-PAHs are a class of emerging pollutants known for their toxicity, persistence, and bioaccumulation. These compounds are predominantly released into the atmosphere through the incomplete combustion of organic materials such as forest fires, fossil fuel combustion, wood burning, and industrial processes. Alkyl-PAHs are typically found in PM as a complex mixture of isobaric isomers, originating from varying sources and exhibiting different toxicity. Compared to their unsubstituted parent-PAHs, many Alkyl-PAHs show higher toxicity and mutagenic potency, underscoring the urgent need for advanced analytical methods to monitor their presence and their fate in the environment and identify their sources. While current SPMS methods can recognize PAHs pattern in PM, they fall short in distinguish between different isomeric compounds and lack the ability to provide quantitative data. In contrast, GC×GC-MS is a powerful tool capable to distinguish between isomeric compounds and quantify them but does not provide insights into the distribution of these compounds across individual particles, thus losing crucial information on particle mixing states and diversity. The proposed cross-platform approach, combining simultaneous GC×GC-MS and SPMS, will provide a comprehensive understanding of Alkyl-PAHs, and organic pollutants in general, at both the bulk and single-particle level, enabling better insights into their atmospheric behavior, sources, and potential health impacts. Moreover, this innovative methodology has the potential to serve as a valuable tool for setting regulatory limits aligned with the European Union´s air quality targets, and for incorporating Alkyl-PAHs into routine environmental monitoring programs. Moreover, the combination of SPMS and GC×GC MS hold the potential to elucidate fundamental processes, including the size distributions of organic matter in the aerosol and the aerosol mixing state.

• DFG Programme: Position