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Identification of linoleic acid free radicals and other breakdown products using spin trapping with liquid chromatography‐electrospray tandem mass spectrometry
Author(s) -
Reis A.,
Domingues M. R. M.,
Amado F. M. L.,
FerrerCorreia A. J. V.,
Domingues P.
Publication year - 2006
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.536
Subject(s) - chemistry , linoleic acid , adduct , radical , mass spectrometry , chromatography , electrospray , tandem mass spectrometry , organic chemistry , fatty acid
Linoleic acid radical products formed by radical reaction (Fenton conditions) were trapped using 5,5‐dimethyl‐1‐pyrrolidine‐ N ‐oxide (DMPO) and analysed by reversed‐phase liquid chromatography coupled to electrospray mass spectrometry (LC‐MS). The linoleic acid radical species detected as DMPO spin adducts comprised oxidized linoleic acid and short‐chain radical species that resulted from the breakdown of carbon and oxygen centred radicals. Based on the m / z values, the short‐chain products were identified as alkyl and carboxylic acid DMPO radical adducts that exhibited different elution times. The ions identified as DMPO radical adducts were studied by liquid chromatography–tandem mass spectrometry (LC‐MS/MS). The LC‐MS/MS spectra of linoleic acid DMPO radical adducts exhibited the fragment ion at m / z 114 and/or the loss of neutral molecule of 113 Da (DMPO) or 131Da (DMPO + H2O), indicated to be DMPO adducts. The short‐chain products identified allowed inference of the radical oxidation along the linoleic acid chain by abstraction of hydrogen atoms in carbon atoms ranging from C‐8 to C‐14. Other ions containing the fragment ion at m / z 114 in the LC‐MS/MS spectra were attributed to DMPO adducts of unsaturated aldehydes, hydroxy‐aldehydes and oxocarboxylic acids. The identification of aldehydic products formed by radical oxidation of linoleic acid peroxidation products, as short‐chain product DMPO adducts, is a means of identifying lipid peroxidation products. Copyright © 2005 John Wiley & Sons, Ltd.