Structures and reactivity of peroxy radicals and dimeric products revealed by online tandem mass spectrometry.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33436593.
- Also identified by DOI 10.1038/s41467-020-20532-2 and PMC identifier 7804243.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Organic peroxy radicals (RO<sub>2</sub>) play a pivotal role in the degradation of hydrocarbons. The autoxidation of atmospheric RO<sub>2</sub> radicals produces highly oxygenated organic molecules (HOMs), including low-volatility ROOR dimers formed by bimolecular RO<sub>2</sub> + RO<sub>2</sub> reactions. HOMs can initiate and greatly contribute to the formation and growth of atmospheric particles. As a result, HOMs have far-reaching health and climate implications. Nevertheless, the structures and formation mechanism of RO<sub>2</sub> radicals and HOMs remain elusive. Here, we present the in-situ characterization of RO<sub>2</sub> and dimer structure in the gas-phase, using online tandem mass spectrometry analyses. In this study, we constrain the structures and formation pathway of several HOM-RO<sub>2</sub> radicals and dimers produced from monoterpene ozonolysis, a prominent atmospheric oxidation process. In addition to providing insights into atmospheric HOM chemistry, this study debuts online tandem MS analyses as a unique approach for the chemical characterization of reactive compounds, e.g., organic radicals.