title: Formation of formaldehyde and malonaldehyde by photooxidation of squalene.
abstract: Formaldehyde and malonaldehyde were identified upon exposure of squalene to ultraviolet (UV) irradiation at 300 nm. Formaldehyde was derivatized by reaction with cysteamine to form thiazolidine; malonaldehyde was derivatized by reaction with N-methylhydrazine to produce N-methylpyrazole. The derivatives were subsequently analyzed with a gas chromatograph equipped with a fused silica capillary column and a nitrogen/phosphorus detector. The levels of formaldehyde and malonaldehyde produced increased with irradiation time. The amount of formaldehyde produced reached a maximum of 3.40 nmol/mg squalene after 7 hr irradiation; the maximum amount of malonaldehyde generated, 0.92 nmol/mg, was found after 5 hr of irradiation. Prior to this study, formaldehyde had not been reported as a photoproduct of squalene. Acetaldehyde and acetone were also detected in the irradiated squalene, which may be formed via a 6-methyl-5-hepten-2-one intermediate. 6-Methyl-5-hepten-2-one can also undergo breakdown to form malonaldehyde.
authors.affiliation: Department of Environmental Toxicology, University of California, Davis 95616.
authors.forename: H C
authors.initials: HC
authors.lastname: Yeo
authors.forename: T
authors.initials: T
authors.lastname: Shibamoto
mesh_terms: D005557:Formaldehyde / Q000138:chemical synthesis; D015227:Lipid Peroxidation; D008315:Malondialdehyde / Q000138:chemical synthesis; D013185:Squalene / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D005557:Formaldehyde; D008315:Malondialdehyde; D013185:Squalene