34 research outputs found
Gas phase hydration of methyl glyoxal to form the gemdiol
No full textMethylglyoxal is a known oxidation product of volatile organic compounds (VOCs) in Earth’s atmosphere. While the gas phase chemistry of methylglyoxal is fairly well understood, its modeled concentration and role in the formation of secondary organic aerosol (SOA) continues to be controversial. The gas phase hydration of methylglyoxal to form a gemdiol has not been widely considered for water-restricted environments such as the atmosphere. However, this process may have important consequences for the atmospheric processing of VOCs. We will report on spectroscopic work done in the Vaida laboratory studying the hydration of methylglyoxal and discuss the implications for understanding the atmospheric processing and fate of methylglyoxal and similar molecules
Gas phase hydration of methyl glyoxal to form the gemdiol
No full textMethylglyoxal is a known oxidation product of volatile organic compounds (VOCs) in Earth’s atmosphere. While the gas phase chemistry of methylglyoxal is fairly well understood, its modeled concentration and role in the formation of secondary organic aerosol (SOA) continues to be controversial. The gas phase hydration of methylglyoxal to form a gemdiol has not been widely considered for water-restricted environments such as the atmosphere. However, this process may have important consequences for the atmospheric processing of VOCs. We will report on spectroscopic work done in the Vaida laboratory studying the hydration of methylglyoxal and discuss the implications for understanding the atmospheric processing and fate of methylglyoxal and similar molecules.Made available in DSpace on 2017-01-26T21:39:35Z (GMT). No. of bitstreams: 4
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Previous issue date: 2016-06-2
Ultraviolet study of the gas phase hydration of methylglyoxal to form the gemdiol
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Previous issue date: 6Methylglyoxal is a known oxidation product of volatile organic compounds (VOCs) in Earth’s atmosphere. While the gas phase chemistry of methylglyoxal is fairly well understood, its modeled concentration and role in the formation of secondary organic aerosol (SOA) continues to be controversial. The gas phase hydration of methylglyoxal to form a gemdiol has been shown to occur in infrared studies but has not been widely considered for water-restricted environments such as the atmosphere. However, this process may have important consequences for the atmospheric processing or VOCs. We have recorded UV spectroscopic measurements following the hydration of methylglyoxal and have compared these measurements to calculated spectra of the electronic transitions of methylglyoxal and methylglyoxal diol. We will report on these measurements and discuss the implications for understanding the atmospheric processing and fate of methylglyoxal and similar molecule
Examining Interdisciplinary Sustainability Institutes at Major Research Universities: Innovations in Cross-Campus and Cross-Disciplinary Models.
No full textThis is a study of the distinctive characteristics, activities, challenges and opportunities of a specific type of sustainability institute, one that spans the many disciplines of the University and, to do so, reports to upper administration (Provost or Vice President.) Among research universities within the Association of American Universities (AAU), 19 are identified and 18 agreed to participate in this study. Directors were sent a 71-question survey in January 2017 that covered issues of Governance, Research, Education, Engagement, Campus Operations and Best Practiceshttps://deepblue.lib.umich.edu/bitstream/2027.42/136638/1/1366_Hoffman.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136638/4/1366_Hoffman_June2017.pdfDescription of 1366_Hoffman_June2017.pdf : June 2017 revisio
VIBRATIONAL SPECTROSCOPY OF PHOTOREACTIVE MOLECULES IN ATMOSPHERIC CHEMISTRY
No full textAuthor Institution: Department of chemistry and Biochemistry, University of Colorado, Boulder, CO 80309Vibrational overtone spectra of oxidized atmospheric chromophores are presented and analyzed to energies where chemistry through vibrational overtone pumping is possible. Experimental near infrared and visible spectra complemented by dynamical theory are presented to elucidate the light initiated reaction dynamics of pyruvic and of glyoxilic acid photo-decarboxylation. The role of water is investigated by making use of vibrational spectra of hydrates of the title compounds. Consequences of water and sunlight mediated chemistry to formation of secondary organic aerosol in the atmosphere will be discussed.\\ \\ \noindent K. L. Plath, J. L. Axson, G. C. Nelson, K. Takahashi, R. T. Skodje and V. Vaida {em React. Kineti. Catal. Lett.} \textbf{96}, 209 (2009)\\ V. Vaida {\em J. Phys. Chem. A} \textbf{113}, 5 (2009)\\ K. Takahashi, K. L. Plath, R. T. Skodje and V. Vaida {\em J. Phys. Chem A} \textbf{112} 7321 (2008
Detection of Active Microbial Enzymes in Nascent Sea Spray Aerosol: Implications for Atmospheric Chemistry and Climate
No full textThe oceans cover nearly three-quarters
of the Earth’s surface
and produce vast quantities of sea spray aerosols (SSA). Studies have
shown that due to ocean biology SSA particles are comprised of much
more than just sea salt and often include proteins, lipids, sugars,
viruses, and bacteria. In this study, we show for the first time that
a diverse array of microbial enzymes (protease, lipases, and alkaline
phosphatase) are transferred from the ocean into the atmosphere and
often become even more active with measured activities in SSA particles
that are 1–2 orders of magnitude higher than those in bulk
seawater. We hypothesize that these enzymatic reactions are enhanced
in the interfacial environment of droplets and aerosols that can dynamically
modify surface chemical species and properties. Simulations reveal
that enzyme-containing SSA particles can rapidly coagulate with other
preexisting aerosols, thus transferring the impact of enzyme reactions
to a broad range of marine aerosols. These biotic reaction pathways
are expected to profoundly change the composition of marine aerosols,
particularly at the interface, and thus will impact cloud properties
in marine environments. Future studies are needed to determine how
photochemistry, changing ocean conditions in a warming climate, and
other external factors will influence the activities of these enzymes
and their impact on the composition of the marine atmosphere
Advancing Model Systems for Fundamental Laboratory Studies of Sea Spray Aerosol Using the Microbial Loop
No full textSea spray aerosol (SSA) particles
represent one of the most abundant
surfaces available for heterogeneous reactions to occur upon and thus
profoundly alter the composition of the troposphere. In an effort
to better understand tropospheric heterogeneous reaction processes,
fundamental laboratory studies must be able to accurately reproduce
the chemical complexity of SSA. Here we describe a new approach that
uses microbial processes to control the composition of seawater and
SSA particle composition. By inducing a phytoplankton bloom, we are
able to create dynamic ecosystem interactions between marine microorganisms,
which serve to alter the organic mixtures present in seawater. Using
this controlled approach, changes in seawater composition become reflected
in the chemical composition of SSA particles 4 to 10 d after the peak
in chlorophyll-a. This approach for producing and varying the chemical
complexity of a dominant tropospheric aerosol provides the foundation
for further investigations of the physical and chemical properties
of realistic SSA particles under controlled conditions
Nanoparticle Digestion Simulator Reveals pH-Dependent Aggregation in the Gastrointestinal Tract
No full textDynamics and spectroscopy of vibrational overtone excited glyoxylic acid and 2,2-dihydroxyacetic acid in the gas-phase
No full textSpectroscopic Determination of Aerosol pH from Acid–Base Equilibria in Inorganic, Organic, and Mixed Systems
No full text
