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

Aqueous solutions of coumarin have been used to detect the hydroxyl radicals produced as a result of gamma radiolysis. Reverse-phase chromatography and fluorescence measurements show that the 7-hydroxycoumarin (umbelliferone) is produced. The hydroxycoumarin isomers of 3OH-, 4OH-, 5OH-, 6OH- and 8OH-coumarin are also produced although the fluorescence emission of these products is negligible compared to that of 7-hydroxycoumarin. The radiation chemical yield of 7-hydroxycoumarin has been studied in different gas conditions.