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Full-Text Articles in Physical Sciences and Mathematics

Method Considerations For Compound Identification In Complex Mixtures Using Electrospray Ionization Ultrahigh Resolution Mass Spectrometry, Tyler Leverton Jan 2019

Method Considerations For Compound Identification In Complex Mixtures Using Electrospray Ionization Ultrahigh Resolution Mass Spectrometry, Tyler Leverton

Dissertations, Master's Theses and Master's Reports

Biomass burning aerosols are highly complex organic mixtures of thousands of components with consequences for global climate. Complex mixture component identification requires accurate mass measurement capability to separate components on a milli-Dalton scale, frequently using ultrahigh resolution mass spectrometry with electrospray ionization. Certain sample preparations and the ionization process may introduce artifacts that obscure the composition of the sample. Two method considerations were explored using isotopically labeled 15NH4OH and MeOH-d3 to track artifact formation in biomass burning samples. Informatics techniques and a custom molecular formula assignment software were used to identify the isotopic atoms in artifact …


Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman Apr 2017

Oxidation Of Substituted Catechols At The Air-Water Interface: Production Of Carboxylic Acids, Quinones, And Polyphenols, Elizabeth A. Pillar, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic activities contribute benzene, toluene, and anisole to the environment, which in the atmosphere are converted into the respective phenols, cresols, and methoxyphenols by fast gas-phase reaction with hydroxyl radicals (HO(•)). Further processing of the latter species by HO(•) decreases their vapor pressure as a second hydroxyl group is incorporated to accelerate their oxidative aging at interfaces and in aqueous particles. This work shows how catechol, pyrogallol, 3-methylcatechol, 4-methylcatechol, and 3-methoxycatechol (all proxies for oxygenated aromatics derived from benzene, toluene, and anisole) react at the air-water interface with increasing O3(g) during τc ≈ 1 μs contact time and contrasts their …


Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman Sep 2015

Heterogeneous Oxidation Of Catechol, Elizabeth A. Pillar, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

Natural and anthropogenic emissions of aromatic hydrocarbons from biomass burning, agro-industrial settings, and fossil fuel combustion contribute precursors to secondary aerosol formation (SOA). How these compounds are processed under humid tropospheric conditions is the focus of current attention to understand their environmental fate. This work shows how catechol thin films, a model for oxygenated aromatic hydrocarbons present in biomass burning and combustion aerosols, undergo heterogeneous oxidation at the air–solid interface under variable relative humidity (RH = 0–90%). The maximum reactive uptake coefficient of O3(g) by catechol γO3 = (7.49 ± 0.35) × 10–6 occurs for …