Development of a Relative Rate Technique to Measure Criegee Intermediate Reactivity

Criegee intermediates (CIs) play a major role in atmospheric chemistry, contributing to aerosol formation and oxidizing capacity. To assess this contribution, the kinetics of bimolecular reactions of CIs must first be established. However, few techniques are available for this purpose, limiting our understanding of CIs in the atmosphere. Accordingly, we develop a precise, economical, and highly accessible strategy for acquiring kinetic data using a relative rate approach. This method exploits highly symmetrical alkenes that produce a single type of CI through ozonolysis. By suppressing other reactive species (e.g., OH radical) formed in these systems, we probe the reactivity of CIs toward a selection of acids and alcohols, where decays of reactants were tracked using proton-transfer reaction mass spectrometry. In this proof-of-principle paper, we find that this approach can be applied to a broad variety of compounds, allowing us to access reactions with lower volatility species, extending and augmenting the CI kinetic database toward a class of reaction that may be significant for aerosol formation.