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Titre du Document
Environmentally Persistent Free Radicals (EPFRs). 1. Generation of Reactive Oxygen Species in Aqueous Solutions
Auteur(s)
KHACHATRYAN Lavrent ; VEJERANO Eric ; LOMNICKI Slawo ; ...
Résumé
Reactive oxygen species (ROS) generated by environmentally persistent free radicals (EPFRs) of 2-monochlorophenol, associated with CuO/silica particles, were detected using the chemical spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy. Yields of hydroxyl radical (˙OH), superoxide anion radical (O2˙), and hydrogen peroxide (H2O2) generated by EPFR―particle systems were reported. Failure to trap superoxide radicals in aqueous solvent, formed from reaction of EPFRs with molecular oxygen, results from fast transformation of the superoxide to hydrogen peroxide. However, formation of superoxide as an intermediate product in hydroxyl radical formation in aprotic solutions of dimethyl sulfoxide (DMSO) and acetonitrile (AcN) was observed. Experiments with superoxide dismutase (SOD) and catalase (CAT) confumed formation of superoxide and hydrogen peroxide, respectively, in the presence of EPFRs. The large number of hydroxyl radicals formed per EPFR and monotonic increase of the DMPO―OH spin adduct concentration with incubation time suggest a catalytic cycle of ROS formation.
Editeur
American Chemical Society
Identifiant
ISSN : 0013-936X CODEN : ESTHAG
Source
Environmental science & technology A. 2011, vol. 45, n° 19, pp. 8559-8566 [8 pages] [bibl. : 53 ref.]
Langue
Anglais
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