Abstract
Abstract. Aerosol mass spectrometers (AMS) are frequently applied in atmospheric aerosol research in connection with climate, environmental or health-related projects. This is also true for the measurement of the organic fraction of particulate matter, still the least understood group of components contributing to atmospheric aerosols. While quantification of the organic and/or inorganic aerosol fractions is feasible, more detailed information about individual organic compounds or compound classes can usually not be provided by AMS measurements. In this study, we present a new method to detect organic peroxides in the particle phase in real-time using an AMS. Peroxides (ROOR') are of high interest to the atmospheric aerosol community due to their potentially high mass contribution to SOA, their important role in new particle formation and their function as “reactive oxygen species” in aerosol–health-related topics. To do so, supersaturated gaseous triphenylphosphine (TPP) was continuously mixed with the aerosol flow of interest in a condensation/reaction volume in front of the AMS inlet. The formed triphenylphosphine oxide (TPPO) from the peroxide–TPP reaction was then detected by an aerosol mass spectrometer (AMS), enabling the semiquantitative determination of peroxide with a time resolution of 2 min. The method was tested with freshly formed and aged biogenic VOC and ozone SOA as well as in a short proof-of-principle study with ambient aerosol.
Highlights
Atmospheric aerosols attract attention in atmospheric research owing to their effects on climate and human health
Since the peroxide determination is based on the measurement of triphenylphosphine oxide (TPPO), this background signal has to be taken into account
The ozonolysis of α- and βpinene in the presence of ammonium sulfate seed aerosol was used to demonstrate the potential of the analytical procedure
Summary
Atmospheric aerosols attract attention in atmospheric research owing to their effects on climate and human health. One highly relevant class of compounds which is assumed to play an essential role in SOA formation, including participation in new particle formation, are organic peroxides (Bonn et al, 2004; Mochida et al, 2006; Reinnig et al, 2008, 2009; Tobias et al, 2000; Tobias and Ziemann, 2002; Zhou et al, 2018; Bianchi et al, 2016, 2017, 2019; Ziemann, 2002, 2003; Kahnt et al, 2018; Zhang et al, 2017; Lee et al, 2019) Besides their significant contribution to SOA mass (Docherty et al, 2005; Ziemann and Atkinson, 2012), particle-phase peroxides are especially interesting due to their often very low saturation vapor pressure, when they contain several hydroperoxy groups induced by autoxidation (Tröstl et al, 2016; Krapf et al, 2016).
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