EGU21-14313
https://doi.org/10.5194/egusphere-egu21-14313
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

New halogenated trace gases discovered by non-target screening of the atmosphere at the Jungfraujoch high alpine station (Switzerland)

Myriam Guillevic1, Martin K. Vollmer1, Matthias Hill1, Paul Schlauri1, Aurore Guillevic2, Lukas Emmenegger1, and Stefan Reimann1
Myriam Guillevic et al.
  • 1Empa, Swiss Federal Laboratories for Materials Science and Technology, Air Pollution / Environmental Technology, Dübendorf, Switzerland (myriam.guillevic@empa.ch)
  • 2Université de Lorraine, CNRS, Inria, LORIA, Nancy, France

Non-target screening consists in searching for all present substances in a sample, suspected or unknown, with very little prior knowledge about the sample. This approach has been introduced more than a decade ago in the field of water analysis or forensics, but is still very scarce in the field of indoor and atmospheric trace gas measurements, despite the urgent need for a better understanding of the composition of the atmosphere.

Recently, we have installed a novel analytical system at the Jungfraujoch high alpine station (3500 m.a.s.l., Switzerland), allowing us to conduct non-target screening of the atmosphere. The system is composed of a preconcentration unit followed by gas chromatography (GC), electron ionisation (EI), and time-of-flight high-resolution mass spectrometry (HRMS). This allows screening the air for all mass fragments from approx. 25 m/z up to 300 m/z, produced by compounds with boiling points from -128 °C (NF3, CF4) to +140 °C (e.g., CHBr3, chlorobenzene, parachlorobenzotrifluoride PCBTF).

Here, we present a new and innovative method to detect and identify unknown organic substances in ambient air using GC-EI-HRMS. We developed an algorithm combining the identification of atom assemblage for the detected fragments and the reconstruction of a pseudo-fragmentation tree, linking fragments belonging to the same substance. This supports in particular the identification of substances for which no mass spectrum is registered in databases. Moreover, we developed a quality control strategy to ensure that the compounds have been correctly identified and are separated from potential coelutants.

Finally, we present a selection of halogenated compounds newly detected in air, measured for the first time at the Jungfraujoch station.

How to cite: Guillevic, M., Vollmer, M. K., Hill, M., Schlauri, P., Guillevic, A., Emmenegger, L., and Reimann, S.: New halogenated trace gases discovered by non-target screening of the atmosphere at the Jungfraujoch high alpine station (Switzerland), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14313, https://doi.org/10.5194/egusphere-egu21-14313, 2021.

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