Formation of Oligomers in Secondary Organic Aerosol
| Autor: | Michael P. Tolocka, Richard M. Kamens, Joy M. Ginter, Myoseon Jang, Murray V. Johnston, Frederick J. Cox |
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| Rok vydání: | 2004 |
| Předmět: |
Aerosols
Air Pollutants Spectrometry Mass Electrospray Ionization Reaction mechanism Polymers Electrospray ionization General Chemistry Photochemistry Tandem mass spectrometry Chemical reaction Oligomer chemistry.chemical_compound Matrix-assisted laser desorption/ionization Monomer chemistry Aldol reaction Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization Environmental Chemistry Organic chemistry Organic Chemicals Volatilization Environmental Monitoring |
| Zdroj: | Environmental Science & Technology. 38:1428-1434 |
| ISSN: | 1520-5851 0013-936X |
| Popis: | The formation of oligomeric molecules, an important step in secondary organic aerosol production, is reported. Aerosols were produced by the reaction of alpha-pinene and ozone in the presence of acid seed aerosol and characterized by exact mass measurements and tandem mass spectrometry. Oligomeric products between 200 and 900 u were detected with both electrospray ionization and matrix-assisted laser desorption ionization. The exact masses and dissociation products of these ions were consistent with various combinations of the known primary products of this reaction ("monomers") with and/or without the expected acid-catalyzed decomposition products of the monomers. Oligomers as large as tetramers were detected. Both aldol condensations and gem-diol reactions are suggested as possible pathways for oligomer formation. Exact mass measurements also revealed reaction products that cannot be explained by simple oligomerization of monomers and monomer decomposition products, suggesting the existence of complex reaction channels. Chemical reactions leading to oligomer formation provide a reasonable answer to a difficult problem associated with secondary organic aerosol production in the atmosphere. It is unlikely that monomers alone play an important role in the formation and growth of nuclei in the atmosphere as their Kelvin vapor pressures are too high for them to significantly partition into the particle phase. Polymerization provides a mechanism by which partitioning to the particle phase becomes favored. |
| Databáze: | OpenAIRE |
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