Yield for the scavenging of hydroxyl radicals in the radiolysis of nitrous oxide-saturated aqueous solutions

Schüler, Robert H.; Patterson, L. K.; Janata, E.

doi:10.1021/j100453a020

Cited by 269 publications

(177 citation statements)

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“…Absorbances were converted into concentrations by dividing with the corresponding extinction coefficients. The SCN • extinction coefficient at 330 nm (1200 M -1 cm -1 ) was taken from ref 20, and the (SCN) 2 •-extinction coefficient at 472 nm (7580 M -1 cm -1 ) was taken from ref 21. The yield of hydrated electrons was taken as 3.4 electrons per 100 eV in agreement with the experiment.…”

Section: Resultsmentioning

confidence: 89%

Pulse Radiolysis of Aqueous Thiocyanate Solution

Milosavljevic

LaVerne

2004

J. Phys. Chem. A

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The pulse radiolysis of N 2 O saturated aqueous solutions of KSCN was studied under neutral pH conditions. The observed optical absorption spectrum of the SCN • radical in solution is more complex than previously reported, but it is in good agreement with that measured in the gas phase. Kinetic traces at 330 and 472 nm corresponding to SCN • and (SCN) 2•-, respectively, were fit using a Monte Carlo simulation kinetic model. The rate coefficient for the oxidation of SCN -ions by OH radicals, an important reaction used in competition kinetics measurements, was found to be (1.4 ( 0.1) × 10 10 M -1 s -1 , about 30% higher than the normally accepted value. A detailed discussion of the reaction mechanism is presented.

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Section: Resultsmentioning

confidence: 89%

Pulse Radiolysis of Aqueous Thiocyanate Solution

Milosavljevic

LaVerne

2004

J. Phys. Chem. A

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“…The radiolysis of neutral water leads to the formation of three highly reactive species: e aq -(2.6), · OH (2.7) and H · (0.6) in addition to the formation of less reactive products, H 2 O 2 (0.7), H 2 (0.45) and H 3 O + (2.6) (numbers in parentheses are the radiation yield values defined as the number of the species formed per 100 eV energy absorbed) [14]. The dose absorbed per pulse was measured on the basis of the initial yield of (SCN) 2 ·-formed in the N 2 O-saturated 0.01 M KSCN aqueous solution assuming a radiation yield 6.13 and an extinction coefficient of 7580 M -1 cm -1 at 472 nm [15].…”

Section: Pulse Radiolysismentioning

confidence: 99%

Pulse radiolysis and steady-state analyses of the reaction between hydroethidine and superoxide and other oxidants

Zielonka¹,

Sarna²,

Roberts³

et al. 2006

Archives of Biochemistry and Biophysics

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Hydroethidine (HE) is a cell-permeable probe used for the intracellular detection of superoxide. Here we report the direct measurement of the rate constant between hydroethidine and superoxide radical anion using the pulse radiolysis technique. This reaction rate constant was calculated to be ca. 2·10 6 M -1 s -1 in water:ethanol (1:1) mixture. The spectral characteristics of the intermediates indicated that the one-electron oxidation product of HE was different from the one-electron reduction product of ethidium (E + ). The HPLC-electrochemical measurements of incubation mixtures containing HE and the oxygenated Fenton's reagent (Fe 2+ /DTPA/H 2 O 2 ) in the presence of aliphatic alcohols or formate as a superoxide generating system revealed 2-OH-E + as a major product. Formation of 2-OH-E + by the Fenton's reagent without additives was shown to be superoxide dismutase-sensitive and we attribute the formation of superoxide radical anion to the one-electron reduction of oxygen by the DTPA-derived radical. Addition of tert-butanol, DMSO, and potassium bromide to the Fenton's system caused inhibition of 2-OH-E + formation. Results indicate that reducing and oxidizing radicals have differential effects on the formation of 2-OH-E + .

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“…Data gathering and analysis techniques are described in [19,20]. The (CNS); ion was used for dosimetry [21]. Phosphate-buffered (5 mM) solutions of Fe(III)chelate (0.1 mM) containing 20 mM sodium formate were prepared immediately before radiation.…”

Section: Hedtamentioning

confidence: 99%

The kinetics of the reaction of superoxide radical with Fe(III) complexes of EDTA, DETAPAC and HEDTA

1983

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To gain an understanding of the mechanism by which the hydroxyl free radical can arise in superoxide generating systems and learn how different chelaters of iron can inhibit this reaction, a pulse radiolysis kinetic study of the reaction of O;-with Fe(III)EDTA, Fe(III)HEDTA and Fe(III)DETAPAC (or DTPA) was undertaken. Superoxide reacts readily with Fe(III)EDTA and Fe(III)HEDTA with a pH-dependent second-order rate constant having values of 1.9 x lo6 M-l. s-' and 7.6 x 16 M-'. s-' at pH 7, respectively. However, the rate constant for the reaction of O;-with Fe(III)DETAPAC was found to be much slower, the upper limit for the rate constant being 104 M-l. s-l. These results in conjunction with spin-trapping experiments with Fe(II)EDTA, Fe(II)HEDTA, Fe(II)DETAPAC and Hz02 suggests that DETAPAC inhibits the formation of 'OH by slowing the reduction of Fe(II1) to Fe(I1) and not by inhibiting the Fenton reaction.

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Yield for the scavenging of hydroxyl radicals in the radiolysis of nitrous oxide-saturated aqueous solutions

Abstract: ErratumRyu HJ, Kim DY, Park JY, Chang HY, Lee MH, Han K-H, Chon CY, Ahn SH. Clinical features and prognosis of hepatocellular carcinoma with respect to pre-S deletion and basal core promoter mutations of hepatitis B virus genotype C2.

Cited by 269 publications

References 0 publications

Pulse Radiolysis of Aqueous Thiocyanate Solution

Pulse Radiolysis of Aqueous Thiocyanate Solution

Pulse radiolysis and steady-state analyses of the reaction between hydroethidine and superoxide and other oxidants

The kinetics of the reaction of superoxide radical with Fe(III) complexes of EDTA, DETAPAC and HEDTA

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