Title
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The acid effect in the formation of 2-methyltetrols from the photooxidation of isoprene in the presence of $NO_{x}$
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Author
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Abstract
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The objectives of this study were to obtain insights into acid effects in the formation of secondary organic aerosol and 2-methyltetrols from the photooxidation of isoprene in the presence of NOx. A photooxidation experiment was performed with isoprene in the presence of NOx where the gaseous reaction mixture was passed over a sulfuric acid-treated and non-treated quartz fibre filter. Consistent with previous laboratory data, the organic carbon and 2-methyltetrol amounts on the sulfuric acid-treated filter were significantly enhanced. In addition, oxygenated isoprene products related to the 2-methyltetrols and formed on the sulfuric acid-treated filter were structurally characterized as enol tautomers of 4-hydroxy-1,3-dioxo-2-methylbutane. No evidence could be found for the formation of C5-epoxydiols in the gas phase but very small amounts, about two orders of magnitude lower than those of the 2-methyltetrols, were generated on the sulfuric acid-treated filter. The formation of the 2-methyltetrols and enol tautomers of 4-hydroxy-1,3-dioxo-2-methylbutane is explained by acid-catalyzed reactions of gas-phase nitrooxypolyols. Implications for the measurement of the 2-methyltetrols using gas chromatography/mass spectrometry (GC/MS) with prior trimethylsilylation are discussed. |
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Language
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English
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Source (journal)
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Atmospheric research / Université de Clermont-Ferrand 2. Institut et Observatoire de physique du globe du Puy de Dôme. - Clermont-Ferrand
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Publication
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Clermont-Ferrand
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2010
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ISSN
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0169-8095
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Volume/pages
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98
:2/4
(2010)
, p. 183-189
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ISI
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000284983400001
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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