title: Characterization of oxygenated derivatives of isoprene related to 2-methyltetrols in Amazonian aerosols using trimethylsilylation and gas chromatography/ion trap mass spectrometry.
abstract: In the present study, we have tentatively identified the structures of three oxygenated derivatives of isoprene in Amazonian rain forest aerosols as the C(5) alkene triols, 2-methyl-1,3,4-trihydroxy-1-butene (cis and trans) and 3-methyl-2,3,4-trihydroxy-1-butene. The formation of these oxygenated derivatives of isoprene can be explained by acid-catalyzed ring opening of epoxydiol derivatives of isoprene, namely, 1,2-epoxy-2-methyl-3,4-dihydroxybutane and 1,2-dihydroxy-2-methyl-3,4-epoxybutane. The structural proposals of the C(5) alkene triols were based on chemical derivatization reactions and detailed interpretation of electron and chemical ionization mass spectral data, including data obtained from first-order mass spectra, deuterium labeling of the trimethylsilyl methyl groups, and MS(2) ion trap experiments. The characterization of 2-methyl-1,3,4-trihydroxy-1-butene (cis and trans) and 3-methyl-2,3,4-trihydroxy-1-butene in forest aerosols is important from an atmospheric chemistry viewpoint in that these compounds hint at the formation of intermediate isomeric epoxydiol derivatives of isoprene and as such provide mechanistic insights into the formation of the previously reported 2-methyltetrols through photooxidation of isoprene.
authors.affiliation: Department of Pharmaceutical Sciences, University of Antwerp (Campus Drie Eiken), Belgium.
authors.forename: Wu
authors.initials: W
authors.lastname: Wang
authors.forename: Ivan
authors.initials: I
authors.lastname: Kourtchev
authors.forename: Bim
authors.initials: B
authors.lastname: Graham
authors.forename: Jan
authors.initials: J
authors.lastname: Cafmeyer
authors.forename: Willy
authors.initials: W
authors.lastname: Maenhaut
authors.forename: Magda
authors.initials: M
authors.lastname: Claeys
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D001938:Brazil; D002070:Butadienes / Q000032:analysis* / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D045782:Hemiterpenes / Q000032:analysis* / Q000737:chemistry*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010420:Pentanes / Q000032:analysis* / Q000737:chemistry*; D011891:Rain; D014197:Trees / Q000378:metabolism*; D014297:Trimethylsilyl Compounds / Q000737:chemistry*; D014329:Tropical Climate
chemical_list: D000336:Aerosols; D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; D014297:Trimethylsilyl Compounds; C005059:isoprene; D010100:Oxygen