Journal ArticleDOI
Track effects in radiation chemistry. Concentration dependence for the scavenging of hydroxyl by ferrocyanide in nitrous oxide-saturated aqueous solutions
TLDR
In this paper, the radiation chemical yield for oxidation of ferrocyanide by OH produced in the fast electron radiolysis of N/sub 2/O-saturated aqueous solutions was found to increase from a low concentration limiting yield of 5.2 to values in excess of 6.7.Abstract:
The radiation chemical yield for oxidation of ferrocyanide by OH produced in the fast electron radiolysis of N/sub 2/O-saturated aqueous solutions is found to increase from a low concentration limiting yield of 5.2 to values in excess of 6.7 for ferrocyanide concentrations above 0.1 M. This observed dependence reflects competition between the scavenging reaction and track recombination processes involving OH radicals which occurs on a time scale greater than 10/sup -9/s. By extrapolation an additional yield of -- 1.5 is estimated for OH radicals which recombine at still shorter times. These scavenging studies show that significant amounts of recombination occur within the track even at times as long as 10/sup -6/s. Secondary radicals produced within the track are also subject to recombination processes as is illustrated by the low concentration limit which shows that most OH radicals produced from N/sub 2/O within the track do not escape from the track. In general, for concentrations of reactive solutes greater than -- 10/sup -4/ M, i.e., for k(S) > 10/sup 6/ s/sup -1/, scavenging of OH from the track will contribute significantly to the observed yields and this effect must be taken into account in comparing the results from different radiolytic systems.read more
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Journal ArticleDOI
Re-evaluation of the thiocyanate dosimeter for pulse radiolysis
George V. Buxton,Craig R. Stuart +1 more
TL;DR: In this article, the super-Fricke dosimeter was used as a secondary standard for the thiocyanate dosimeter in O2-saturated water and the results were improved to 3.47 ± 0.06.
Journal ArticleDOI
Methods for reactive oxygen species (ROS) detection in aqueous environments
Justina M. Burns,William J. Cooper,John L. Ferry,D. Whitney King,Brian P. DiMento,Kristopher McNeill,Christopher J. Miller,William L. Miller,Barrie M. Peake,Steven A. Rusak,Andrew L. Rose,T. David Waite +11 more
TL;DR: In this paper, a review summarizes direct and indirect analytical methods for the detection and quantification of reactive oxygen species (ROS): 1O2, O2−/HOO·, H2O2, HO·, and CO3·− in aqueous solution.
Journal ArticleDOI
Reactivity and Role of SO5•- Radical in Aqueous Medium Chain Oxidation of Sulfite to Sulfate and Atmospheric Sulfuric Acid Generation
TL;DR: In this article, the role of peroxymonosulfate anion radical (O3SOO• or SO5•-) intermediate during radical-induced chain oxidation of HSO3/SO32- in oxygenated aqueous solution was evaluated.
Journal ArticleDOI
Scavenging of nitrogen dioxide, thiyl, and sulfonyl free radicals by the nutritional antioxidant beta-carotene.
Steven A. Everett,Madeleine F. Dennis,Kantilal B. Patel,S. Maddix,Subhas C. Kundu,Robin L. Willson +5 more
TL;DR: Mechanisms of free radical scavenging by the nutritional antioxidant β-carotene have been investigated by pulse radiolysis and rate constants for thiyl radical-addition reactions vary from 106 to 109M s and correlate with the lipophilicity of the thiyle radical under study.
Journal ArticleDOI
Free Radical Reactions of Methionine in Peptides: Mechanisms Relevant to β-Amyloid Oxidation and Alzheimer's Disease
TL;DR: Time-resolved UV spectroscopic and conductivity studies with small model peptides show for the first time that Met radical cations in peptides can be stabilized through bond formation with either the oxygen or the nitrogen atoms of adjacent peptide bonds.
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