Abstract
Aerosols of variable composition, size, and shape are associated with public health concerns as well as with light-particle interactions that play a role in the energy balance of the atmosphere. Photochemical reactions of 2-oxocarboxylic acids in the aqueous phase are now known to contribute to the total secondary organic aerosol (SOA) budget. This work explores the cross reaction of glyoxylic acid (GA) and pyruvic acid (PA) in water, the two most abundant 2-oxocarboxylic acids in the atmosphere, under solar irradiation and dark thermal aging steps. During irradiation, PA and GA are excited and initiate proton-coupled electron transfer or hydrogen abstraction and α-cleavage reactions, respectively. The time series of photoproducts is studied by ion chromatography (IC) with conductivity and electrospray ionization (ESI) mass spectrometry (MS) detection, direct ESI-MS analysis in the negative ion mode, and nuclear magnetic resonance spectroscopy (NMR). The use of one-dimensional (1H and 13C NMR) and two-dimensional NMR techniques includes gradient correlation spectroscopy (gCOSY) and heteronuclear single quantum correlation (HSQC). The aging of photoproducts in the dark is monitored by UV–visible spectroscopy. The periodicity in the time domain of the optical properties is explained in terms of chromophores that undergo alternating thermochromism and photobleaching between nighttime and daytime cycles, respectively. A reaction mechanism for the cross reaction of GA and PA explaining the generation of trimers with general formulas C5H8O5 (148 Da), C6H10O5 (162 Da), and C5H8O6 (164 Da) is provided based on all experimental observations.
Document Type
Article
Publication Date
7-12-2018
Digital Object Identifier (DOI)
https://doi.org/10.1021/acs.jpca.8b05724
Funding Information
M.I.G. thanks the National Science Foundation for research funding under NSF CAREER award CHE-1255290. A.J.E. acknowledges support by the NASA Earth and Space Science Fellowship (NESSF) Program.
Related Content
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpca.8b05724.
Additional experimental details, Table S1, Figures S1–S8, and Schemes S1–S6 (PDF)
Repository Citation
Xia, Sha-Sha; Eugene, Alexis J.; and Guzman, Marcelo I., "Cross Photoreaction of Glyoxylic and Pyruvic Acids in Model Aqueous Aerosol" (2018). Chemistry Faculty Publications. 151.
https://uknowledge.uky.edu/chemistry_facpub/151
Additional experimental details, Table S1, Figures S1–S8, and Schemes S1–S6
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Analytical Chemistry Commons, Biochemistry Commons, Environmental Chemistry Commons, Environmental Engineering Commons, Environmental Health Commons, Environmental Sciences Commons, Physical Chemistry Commons
Notes/Citation Information
Published in The Journal of Physical Chemistry A, v. 122, issue 31, p. 6457-6466.
Copyright © 2018 American Chemical Society
This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.