EGU25-12699, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-12699
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Insufficient mass spectrometric detection of synthesized hydroperoxy acids from α-pinene ozonolysis
Markus Tischberger1, Maximilian Kaiser2, Hinrich Grothe1, Marco Lair1, Melanie Opacak1, David Schachamayr2, and Dominik Stolzenburg1
Markus Tischberger et al.
  • 1Institute of Materials Chemistry, TU Wien, Vienna, Austria
  • 2Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria

Alpha-pinene is one of the most studied precursor molecules for new particle formation (NPF). It was shown that RO2 radicals formed by α-pinene ozonolysis can undergo autoxidation to rapidly form highly oxygenated molecules (HOMs) (Bianchi et al, 2019). These HOMs are hypothesized to often contain hydroperoxide (C-O-O-H) functionalization. As the functionalization of molecules influences their vapor pressure, it is an important factor when modeling the formation and growth of new aerosol particles (Stolzenburg et al, 2022).

Authentic standards of α-pinene derived HOMs are sparse. While some research groups have achieved the synthesis of HOM-dimers (see, e.g., Kenseth et al, 2023), monomeric HOM compounds with the significant hydroperoxide functionalization are still not available commercially (Mettke et al, 2022). There is an urgent need to investigate the detection of these compounds in the widely used chemical ionization mass spectrometers, as their charging efficiencies remain largely unknown (Alage et al, 2024).

In this work, we report the synthesis of two α-pinene derived molecules containing hydroperoxy-acid (C(O)-O-O-H) groups, verified by H- and C-NMR techniques. We characterized the synthesized standards using an Orbitrap mass spectrometer with electrospray ionization and NO3- based chemical ionization at atmospheric pressure. We demonstrate that both ionization methods result in much higher signals of the corresponding carboxylic acids. This indicates a rapid destruction of the hydroperoxy acids during the ionization process.

Our results imply that HOMs formed via the autoxidation of α-pinene might often not be correctly quantified with different mass spectrometric techniques. As especially the chemical ionization using NO3- is widely used in atmospheric studies related to NPF, this could result in huge discrepancies when atmospheric process rates (such as nucleation and growth rates of newly formed particles) are derived from gas-phase measurements.

References:

Alage, S. et al (2024), Atmos. Meas. Techn., 17(15), 4709-4724, https://doi.org/10.5194/amt-17-4709-2024

Bianchi, F. et al (2019), Chem. Rev., 119(6), 3472–3509, https://doi.org/10.1021/acs.chemrev.8b00395

Kenseth, C. M. et al (2023), Science, 382(6672), 787-792, https://doi.org/10.1126/science.adi0857

Mettke, P. et al (2022), Atmosphere, 13(4), 507, https://doi.org/10.3390/atmos13040507

Stolzenburg, D. et al (2022), J. Aerosol Sci., 166, 106063, https://doi.org/10.1016/j.jaerosci.2022.106063

How to cite: Tischberger, M., Kaiser, M., Grothe, H., Lair, M., Opacak, M., Schachamayr, D., and Stolzenburg, D.: Insufficient mass spectrometric detection of synthesized hydroperoxy acids from α-pinene ozonolysis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12699, https://doi.org/10.5194/egusphere-egu25-12699, 2025.