title: Formation of oligomeric alkenylperoxides during the oxidation of unsaturated fatty acids: an electrospray ionization tandem mass spectrometry study.
abstract: This study reports the identification of oligomeric alkenylperoxides by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS(2)), during the oxidation of oleic, linoleic and linolenic acids with Fenton's (Fe(2+)/H(2)O(2)) and Fe(2+)/O(2) systems. The reactions were followed by ferrous oxidation-xylenol orange method together with GC-MS and GC-FID, allowing to observe that both oxidation systems are different in terms of hydroperoxide evolution, probably due to the presence of different intermediate reactive species: perferryl ion and OH(·) radical responsible for the decomposition of lipid hydroperoxides and formation of new compounds. The analysis of ESI-MS in the negative mode, obtained after oxidation of each fatty acid, confirmed the presence of the monomeric oxidation products together with other compounds at high mass region above m/z 550. These new ions were attributed to oligomeric structures, identified by the fragmentation pathways observed in the tandem mass spectra.
authors.affiliation: CICECO and Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. jjvillaverde@ua.pt
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Villaverde
authors.forename: Sónia A O
authors.initials: SA
authors.lastname: Santos
authors.forename: Elisabete
authors.initials: E
authors.lastname: Maciel
authors.forename: Mário M Q
authors.initials: MM
authors.lastname: Simões
authors.forename: Carlos
authors.initials: C
authors.lastname: Pascoal Neto
authors.forename: M Rosário M
authors.initials: MR
authors.lastname: Domingues
authors.forename: Armando J D
authors.initials: AJ
authors.lastname: Silvestre
mesh_terms: D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000737:chemistry*; D010636:Phenols; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013454:Sulfoxides; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014992:Xylenes / Q000737:chemistry
chemical_list: D005231:Fatty Acids, Unsaturated; D008054:Lipid Peroxides; D010636:Phenols; D013454:Sulfoxides; D014992:Xylenes; C016833:xylenol orange