The reaction of coumarin with the OH radical revisited: hydroxylation product analysis determined by fluorescence and chromatography

Radiolysis of Confined Water: Production and Reactivity of Hydroxyl Radicals

“…In aqueous solution, nonfluorescent coumarin is converted on irradiation into fluorescent 7-hydroxycoumarin (7-OHC). [10][11][12][13][14] The fluorescence intensity is proportional to the number of 7-OHC molecules formed, and this in turn is proportional to the locally available HOC concentration down to 10 À8 mol dm À3 . Such a selectivity and sensitivity with respect to HOC can not be achieved by measuring the bleaching of a dye under irradiation.…”

“…Above a pore diameter of 150 nm, the behavior of confined coumarin solutions is similar to that of homogenous solutions. [10,17] Such results can be attributed either to a cagelike effect which favors radical recombination in the pores [2] or to an enhanced surface reaction of HOC at the water/silica interface. [18] To identify a possible role of this interface, CPGs with pore sizes of 8, 50, and 300 nm were filled with various amounts of 1 mm coumarin solution and irradiated as described above.…”

“…Effect of pore size on the yield of 7-OHC in CPGs. The empty circle refers to the yield in solution taken from Louit et al [10] …”

Chapter Green Nanotechnology: Development of Nanomaterials for Environmental and Energy Applications

“…Hydroxyl radical spin traps produce a spin adducts which can be measured by electron spin resonance (ESR) spectroscopy (167,168). Terephthalic acid and coumarin react with hydroxyl radical to yield adducts with characteristic fluorescence (169,170). These fluorescence probes are easy to use and excellent for quantification of hydroxyl radical in a variety of systems.…”

The Investigation of Photocatalysts and Iron Based Materials in the Oxidation and the Adsorption of Toxic Organic and Chromium Materials

“…Hydroxyl radical spin traps produce a spin adducts which can be measured by electron spin resonance (ESR) spectroscopy (Fu et al, 2006;Schwarz et al, 1997). Terephthalic acid and coumarin react with hydroxyl radical to yield adducts with characteristic fluorescence (Ishibashi et al, 2000b;Louit et al, 2005). These fluorescence probes are easy to use and excellent for quantification of hydroxyl radical in a variety of systems.…”