Electrodynamic balance–mass spectrometry reveals impact of oxidant concentration on product composition in the ozonolysis of oleic acid

Abstract

The chemical and physical properties of atmospheric aerosol particles change upon oxidative ageing, influencing their interaction with radiation, their propensity to serve as nuclei for cloud condensation and ice formation,...

Oxidation pathways of linoleic acid revisited with electrodynamic balance–mass spectrometry

“…The formation of high molecular weight products would be expected based on the ability of Criegee intermediates to build dimers and oligomers, 44 but the absence of the corresponding peaks is assumed to be a result of thermal decomposition in the evaporation step. 35,45,46 At m / z below 111, the spectra from droplets of unreacted and aged linoleic acid were not apparently different.…”

“…8 in the appendix, the consumption of linoleic acid can be described well with an exponential decay. Exponential curves were fitted to the data taking into account the uncertainty in particle size and calculating a common [LA] 0 for all fits using Bayesian inference as described by Müller et al 35…”

“…This technique has been used to monitor the evaporation of semi-volatile compounds, [25][26][27][28] for quantitative measurements of compounds in droplet mixtures, 29,30 and to study chemical reactions in droplets. [31][32][33][34][35] In our setup, an evaporation unit is used to transfer the compounds into the gas phase and ionise those in a cold plasma ion source before MS analysis. A detailed description of the instrumentation and the typical experimental procedure can be found elsewhere.…”

“…A detailed description of the instrumentation and the typical experimental procedure can be found elsewhere. 35…”

“…This allows to compensate short reaction times in laboratory experiments with high ozone mixing ratios to reach atmospherically relevant ozone exposures. There are, however, a few cases (including linoleic acid oxidation) where this assumption breaks down 14,17,35,[41][42][43] and therefore the extrapolation from a laboratory setting to atmospheric condition needs to be assessed carefully in each case.…”