40 research outputs found
Scavenging of Free-Radical Metabolites of Aniline Xenobiotics and Drugs by Amino Acid Derivatives: Toxicological Implications of Radical-Transfer Reactions
How Easily Oxidizable Is DNA? One-Electron Reduction Potentials of Adenosine and Guanosine Radicals in Aqueous Solution
Carboxyl radical induced cleavage of disulfide bonds in proteins. A .gamma.-ray and pulse radiolysis mechanistic investigation
The Trap Depth (in DNA) of 8-Oxo-7,8-dihydro-2‘deoxyguanosine as Derived from Electron-Transfer Equilibria in Aqueous Solution
Genetic Heterogeneity in a Large Cohort of Indian Type 3 von Willebrand Disease Patients
Photochemical coupling reactions between Fe(III)/Fe(II), Cr(VI)/Cr(III) and polycarboxylates: inhibitory effect of Cr species
The roles of chromium species on photochemical cycling of iron and mineralization of polycarboxylates are examined in the presence of Cr(VI) or Cr(III) at pH 2.2−4.0. Under UV irradiation, Cr(III) altered the redox equilibrium of iron species, leading to the shift of the photosteady state toward Fe(II). After a longer time of illumination, total organic carbon (TOC) approached a steady state in the presence of Cr(III) or Cr(VI), whereas oxalate was thoroughly mineralized in the absence of Cr species. The TOC of steady state was closely related to the kind of polycarboxylates, Cr species dosages, pH and O2 atmosphere, but hardly affected by more addition of Fe(III). ESI-MS data indicates that several Cr−oxalate complexes formed in the photochemical reactions, which are responsible for protecting oxalate against further oxidation. A mechanism is proposed for the inhibitory effect of Cr species on oxidation of oxalate and Fe(II). The present study may provide a new insight into the dual environmental effects induced by Cr contaminants especially at heavily chromium-contaminated and dissolved organic matter (DOM)-rich sites