Quantitation of the hydroxyl radical by reaction with dimethyl sulfoxide

Abstract

This investigation was conducted to validate the use of dimethyl sulfoxide (DMSO) as a quantitative molecular probe for the generation of hydroxyl radicals (HO) in aqueous systems. Reaction of HO with DMSO produces methane sulfinic acid as a primary product, which can be detected by a simple calorimetric assay. To evaluate this method for estimating total HO production, we studied three model systems, including the Fenton reaction,  irradiation of water, and ultraviolet photolysis of hydrogen peroxide, for which the theoretical maximum yield of HO could be calculated and compared to measured DMSO oxidation. The results confirm that 0.05 to 1 M DMSO may be used to capture nearly all of the expected HO radicals formed. Thus, methane sulfinic acid production from DMSO holds promise as an easily measured marker for HO formation in aqueous systems pretreated with DMSO.

Analysis of the biological and chemical reactivity of zeolite-based aluminosilicate fibers and particulates.

“…The reaction of hydroxyl radicals with DMSO has an appreciable rate constant (k = 7 × 10 9 L/mol·sec), and the reported yield for this reaction varies from 85% to 91% (24,25,43). The MSA method gave somewhat lower values than the HPLC method, but the trends in both cases were similar.…”

“…Babbs and Steiner (24,25) developed the spectrophotometric quantification of MSA, and we used a modified version of this method. The photooxidized species from the Fast Blue BB salt solution (C 17 H 18 ClN 3 O 3 )ZnCl 2 (Fluka Chemie; Sigma-Aldrich USA, Milwaukee, WI) was removed by extraction with 1 mL chloroform.…”

“…The difference in the amount of DMSO before and after reaction with hydroxyl radicals was estimated from liquid chromatography. The second method involved UV-visible spectroscopy for estimating MSA formed by reaction of hydroxyl radicals with DMSO, and a detection limit of 100 µmol of MSA was achieved (24,25). Figures 8 and 9 plot the amount of hydroxyl radicals by the HPLC and the UVVis methods, respectively, against the amount of surface iron determined by the polymer exchange method (micrograms iron per gram of zeolite times grams dry zeolite used for the experiment).…”

Interfacial mechanisms of heterogeneous Fenton reactions catalyzed by iron-based materials: A review

“…The scavenging of UOH by Cl − is significant only at low pH (Grebel et al, 2010) (e.g., pH < 2 (Machulek et al, 2006)), while carbonate scavenging of UOH increases with pH (Grebel et al, 2010). (3) The respective stoichiometric reaction between UOH and coumarin, terephthalic acid or DMSO can produce fluorescent or colored products, and can be used for UOH quantification (Huang et al, 2013;Luo et al, 2010;Steiner and Babbs, 1990;Yan et al, 2012). (4) A series of hydroxylated products detected during contaminant degradation can also indicate ·OH existence (Costa et al, 2006(Costa et al, , 2008 (Lin and Gurol, 1998;Pignatello et al, 2006)).…”

Degradation characteristics of humic acid over iron oxides/Fe0 core–shell nanoparticles with UVA/H2O2

“…To compensate for surface charge effects, the binding energies were calibrated using the C 1s hydrocarbon peak at 284.80 eV. The concentration of hydroxyl radicals formed in the catalyst aqueous suspension was determined using a photometric method described in the literature [21,22].…”