Characterization of 2-methylglyceric acid oligomers in secondary organic aerosol formed from the photooxidation of isoprene using trimethylsilylation and gas chromatography/ion trap mass spectrometry.
J Mass Spectrom
; 42(1): 101-16, 2007 Jan.
Article
em En
| MEDLINE
| ID: mdl-17154243
ABSTRACT
In the present work, we have characterized in detail the chemical structures of secondary organic aerosol (SOA) components that were generated in a smog chamber and result from the photooxidation of isoprene under high-NO(x) conditions typical for a polluted atmosphere. Isoprene high-NO(x) SOA contains 2-methylglyceric acid (2-MG) and oligoester derivatives thereof. Trimethylsilylation, in combination with capillary gas chromatography (GC)/ion trap mass spectrometry (MS) and detailed interpretation of the MS data, allowed structural characterization the polar oxygenated compounds present in isoprene SOA up to 2-MG trimers. GC separation was achieved between 2-MG linear and branched dimers or trimers, as well as between the 2-MG linear dimer and isomeric mono-acetate derivatives thereof. The electron ionization (EI) spectra of the trimethylsilyl derivatives contain a wealth of structural information, including information about the molecular weight (MW), oligoester linkages, terminal carboxylic and hydroxymethyl groups, and esterification sites. Only part of this information can be achieved with a soft ionization technique such as electrospray (ESI) in combination with collision-induced dissociation (CID). The methane chemical ionization (CI) data were used to obtain supporting MW information. Interesting EI spectral differences were observed between the trimethylsilyl derivatives of 2-MG linear and branched dimers or trimers and between 2-MG linear dimer mono-acetate isomers.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pentanos
/
Compostos de Trimetilsilil
/
Butadienos
/
Hemiterpenos
/
Poluentes Atmosféricos
/
Glutamatos
/
Cromatografia Gasosa-Espectrometria de Massas
Idioma:
En
Revista:
J Mass Spectrom
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Bélgica