title: Formation and stability of secondary ozonides from monoterpenes studied by mass spectrometry.
abstract: The secondary ozonide (SOZ) of limonene is a potential indoor pollutant from the gas-phase limonene/ozone-reaction. A screening in the liquid phase was performed to investigate the yield and stability of SOZs from ten cyclic monoterpenes. They were cryo-ozonolyzed in pentane, and the reaction mixtures were analyzed with GC-MS with negative and positive chemical ionization and electron ionization. The investigated terpenes were: limonene, 4-carene, 3-carene, 2-carene, terpinolene, (+)-alpha-pinene, (-)-beta-pinene, isolimonene, sabinene and camphene. The only identified endo-SOZs were from: limonene, 3-carene, 4-carene and possibly isolimonene. Collision induced dissociation (CID) of the quasi-molecular-ions as a proxy measure of the stability of the pristine SOZs was investigated. LimoneneSOZ and 3-careneSOZ were found to be more stable than 4-careneSOZ and isolimoneneSOZ, which corresponded well to their relative yields. 3-careneSOZ was found to be a major product from the gas-phase ozonolysis.
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen Ø, Denmark.
authors.forename: Anni
authors.initials: A
authors.lastname: Vibenholt
authors.forename: Asger W
authors.initials: AW
authors.lastname: Nørgaard
authors.forename: Per Axel
authors.initials: PA
authors.lastname: Clausen
authors.forename: Peder
authors.initials: P
authors.lastname: Wolkoff