abstract
This study reports the identification of oligomeric alkenylperoxides by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS2), during the oxidation of oleic, linoleic and linolenic acids with Fenton's (Fe2+/H2O2) and Fe2+/O2 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. Copyright (C) 2012 John Wiley & Sons, Ltd.
keywords
EPOXIDIZED VEGETABLE-OILS; LIQUID-LIQUID SYSTEMS; OXIRANE RING; HYDROPEROXIDES; DEGRADATION; IDENTIFICATION; MECHANISMS; CHEMISTRY; PRODUCTS; HYDROXY
subject category
Biochemistry & Molecular Biology; Chemistry; Spectroscopy
authors
Villaverde, JJ; Santos, SAO; Maciel, E; Simoes, MMQ; Neto, CP; Domingues, MRM; Silvestre, AJD
our authors
Armando Jorge Domingues Silvestre
Full professor
Carlos Pascoal Neto
Raiz Director
Sónia Andreia Oliveira Santos
Assistant Researcheracknowledgements
The authors gratefully acknowledge the financial support provided by the European Research Project (Novel enzyme tools for production of functional oleochemicals from unsaturated lipids (ERA-NOEL), ERA-IB/BIO/0001/2008), CICECO, QOPNA (project PEst-C/QUI/UI0062/2011) and RNEM (REDE/1504/REM/2005 -that concerns the Portuguese Mass Spectrometry Network). Juan Jose Villaverde and Sonia A. O. Santos also thank FCT-Fundacao para a Ciencia e a Tecnologia for the awarding of a postdoctoral grant (BPD/UI89/4520/2009) and a Ph.D. grant (SFRH/BD/42021/2007), respectively.