title: Optimizing electron spin resonance detection of hydroxyl radical in water.
abstract: The parameters affecting the electron spin resonance (ESR) detection of hydroxyl free radical in water are studied and optimized. The hydroxyl radical is generated by the Fenton reaction with iron (II) ammonium sulfate and hydrogen peroxide reacting in a phosphate buffer using N-tert-butyl-alpha-phenylnitron as the spin trap. The concentrations of Fe(2+), H(2)O(2), and phosphate buffer are the parameters studied. The Taguchi method and the orthogonal experiment design were used to evaluate the effects of these parameters on the ESR signal intensity. By the analysis of the signal-to-noise ratio and the analysis of variance, the order of importance of the various parameters on the hydroxyl radical formation is determined for optimal ESR detection of hydroxyl radical. The results will help the development of water purification technologies using hydroxyl free radical as a green oxidant.
authors.affiliation: Department of Chemistry, The University of Hong Kong, Pokfulam Road, SAR, Hong Kong, China.
authors.forename: Shao-An
authors.initials: SA
authors.lastname: Cheng
authors.forename: Wai-Kit
authors.initials: WK
authors.lastname: Fung
authors.forename: Kwong-Yu
authors.initials: KY
authors.lastname: Chan
authors.forename: P K
authors.initials: PK
authors.lastname: Shen
mesh_terms: D000704:Analysis of Variance; D002021:Buffers; D002614:Chelating Agents / Q000737:chemistry; D003497:Cyclic N-Oxides; D004492:Edetic Acid / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000032:analysis*; D007501:Iron / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry; D013113:Spin Labels; D014867:Water / Q000737:chemistry*
chemical_list: D002021:Buffers; D002614:Chelating Agents; D003497:Cyclic N-Oxides; C045076:Fenton's reagent; D009589:Nitrogen Oxides; D013113:Spin Labels; D014867:Water; D017665:Hydroxyl Radical; C029217:phenyl-N-tert-butylnitrone; D004492:Edetic Acid; D006861:Hydrogen Peroxide; D007501:Iron