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Mimicking the atmospheric OH‐radical‐mediated photooxidation of isoprene: formation of cloud‐condensation nuclei polyols monitored by electrospray ionization mass spectrometry
Author(s) -
Silva Santos Leonardo,
Dalmázio Ilza,
Eberlin Marcos N.,
Claeys Magda,
Augusti Rodinei
Publication year - 2006
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.2574
Subject(s) - isoprene , chemistry , electrospray ionization , mass spectrometry , tandem mass spectrometry , electrospray , radical , photochemistry , aerosol , chemical ionization , ionization , ion , organic chemistry , chromatography , copolymer , polymer
Recently, it has been proposed (M. Claeys et al., Science 2004; 303: 1173) that the atmospheric OH‐radical‐mediated photooxidation of isoprene is a source of two major secondary organic aerosol (SOA) components, that is, 2‐methylthreitol and 2‐methylerythritol. These diastereoisomeric tetrols, which were characterized for the first time in the fine size fraction (<2.5 µm aerodynamic diameter) of aerosols collected in the Amazon rain forest during the wet season, were proposed to enhance the capability of the aerosols to act as cloud‐condensation nuclei. In the present study, we performed the oxidation of isoprene in aqueous solution under conditions that attempted to mimic atmospheric OH‐radical‐induced photooxidization, and monitored and characterized on‐line the reaction products via electrospray ionization mass (and tandem mass) spectrometry in the negative ion mode. The results show that the reaction of isoprene with photo‐ or chemically generated hydroxyl radicals indeed yields 2‐methyltetrols. Other polyols were also detected, and they may therefore be considered as plausible SOA components eventually formed in normal or more extreme OH‐radical‐mediated photooxidation of biogenic isoprene. Copyright © 2006 John Wiley & Sons, Ltd.