Atmospheric aerosol have important and extensive effects on the environment. However, many of the processes that lead to the formation of aerosol, particularly aqueous secondary organic aerosol (aqSOA), remain poorly understood due to the complex processing of secondary organic constituents within the aerosol phase leading to hydration, oligomerization, and other reaction products. As the molecular composition of aerosol can significantly influence their properties, it is vital we increase our understanding of how such molecules behave in aqSOA systems. Vibrational sum-frequency (VSF) spectroscopy, a surface sensitive technique, can provide information about interfacial molecular populations and behaviors. Complementary experimental surface tensiometry and computational calculations afford further insights into these systems. A combination of these methods is utilized to investigate methylglyoxal at the air-water interface as a model for aqSOA. Methylglyoxal (MG) is an abundant and atmospherically important aldehyde that is known to participate in SOA formation. MG exists in an equilibrium of two hydration states in bulk water: a single hydrated diol and a doubly hydrated tetrol. Our studies of MG at the neat air-water interface determined that the diol to tetrol ratio is greater at the interface than in the bulk, favoring the diol. Here we present our preliminary studies on MG with non-reactive salts, which indicate an even greater shift in the equilibrium, further favoring the MG diol. This work has important implications for understanding MG’s atmospheric fate and in turn the formation and aging of agSOA.

Experimental and computational VSFS studies on the influence of NaCl on methylglyoxal surface adsorption and hydration state at the air-water interface

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.