Capturing Elusive Volatile Organics in Atmospheric Particles via Dual-Mode Solid-Phase Microextraction Coupled with...

Area of Science:

• Atmospheric Chemistry
• Analytical Chemistry
• Environmental Science

Background:

• Molecular-level characterization of organic aerosol (OA) is crucial but analytically challenging.
• Complex chemical composition and broad volatility distribution hinder OA analysis.

Purpose of the Study:

• Develop a high-sensitivity method for direct OA detection in ambient samples.
• Expand the accessible volatility range for OA analysis.

Main Methods:

• Utilized dual-mode solid-phase microextraction (DM-SPME) integrated with gas chromatography-orbitrap mass spectrometry (GC-Orbitrap MS).
• Combined headspace and direct immersion extraction techniques.
• Performed nontargeted analysis on diverse air samples.

Main Results:

• DM-SPME detected ~50% more compounds and ~40% higher concentrations than conventional solvent extraction.
• Enhanced detection of polycyclic aromatic hydrocarbons, ketones, aldehydes, and aliphatic hydrocarbons.
• Revealed molecular differences across sites, with urban samples showing more oxidized and nitrogen-containing compounds.

Conclusions:

• DM-SPME offers an improved analytical strategy for molecular-level OA analysis.
• The method enhances understanding of OA composition and atmospheric processes.
• Robustness for comparative analysis across different environments was demonstrated.