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Characterization of oxygenated derivatives of isoprene related to 2‐methyltetrols in Amazonian aerosols using trimethylsilylation and gas chromatography/ion trap mass spectrometry
Author(s) -
Wang Wu,
Kourtchev Ivan,
Graham Bim,
Cafmeyer Jan,
Maenhaut Willy,
Claeys Magda
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1940
Subject(s) - isoprene , chemistry , alkene , chemical ionization , mass spectrometry , organic chemistry , mass spectrum , gas chromatography , derivatization , trimethylsilyl , photochemistry , ion , ionization , chromatography , catalysis , polymer , copolymer
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. Copyright © 2005 John Wiley & Sons, Ltd.