Novel Laser Ionization Techniques for Single-particle Mass Spectrometry Reveal the Distribution of Key Compounds for Health Effects on Individual Particles
Johannes Passig, Julian Schade, Robert Irsig, Thomas Kröger-Badge, Sven Ehlert, Andreas Walte, RALF ZIMMERMANN,
Rostock University and Photonion GmbH Abstract Number: 240
Working Group: Instrumentation and Methods
AbstractBesides their climate effects, aerosols represent the largest environmental risk to human health (Lelieveld et al., 2015). The most health-relevant particle compounds are soot, metals and polycyclic aromatic hydrocarbons (PAHs). Single-particle mass spectrometry (SPMS) can detect them in real time (Pratt & Prather, 2012), however, limited sensitivity, matrix effects and molecular fragmentation limit chemical speciation in conventional SPMS. We address these challenges by developing new laser ionization approaches based on resonance effects.
One approach is the application of tunable laser systems, addressing atomic transitions of metals during their laser-driven release from the particle (Passig et al., 2020). This resonant laser desorption/ionization (LDI) enhances detection efficiencies for biologically relevant metals such as iron, zinc or manganese. We could show that important Fe-carriers in the atmosphere are not detected by conventional SPMS but by SPMS with resonant LDI.
We also combine Resonance-Enhanced Multiphoton Ionization (REMPI) of aromatic molecules with LDI of refractory compounds (Schade et al., 2019). This technology produces detailed PAH mass spectra combined with the particles’ inorganic composition, providing novel insight into the sources, distribution and ageing of atmospheric PAHs.
In our commercial instruments, we combine both resonance techniques for PAHs and Fe, a key micronutrient for marine life and a particular health-relevant aerosol compound.
Here we present results from experiments on PAHs in ambient air, the detection of individual ship plumes from the distance and PAH-based source apportionment (Passig et al. 2021, 2022).
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