Studies of Short-lived Radicals in the γ-irradiated Aqueous Solution of Uridine-5′-monophosphate by the Spin-trapping Method and the Liquid Chromatography

Abstract

An aerated aqueous solution cyclic UMP was .gamma.-irradiated with 2-methyl-2-nitrosopropane as a spin-trapping reagent. Liquid chromatography was applied to separate the stable nitroxide radicals in the irradiated solution. The radicals were detected by UV and ESR spectrometry. The ESR detection showed 4 peaks in the chromatogram. The orcinol method for detection of the residual sugar moieties was applied before and after reduction on the base to determine the existence of the 5,6-double bond for the molecules in each fraction. From the combined results of the ESR and orcinol methods, the short-lived radicals which were trapped by 2-methyl-2-nitrosopropane were identified as radicals of N-1 and C-6 positions of the base moiety and tert-butyl radical which was the radiolytic product of the trapping reagent.