Trapped electron (et–) and sugar radical yields in aqueous carbohydrate matrices γ-irradiated at 77 K have been determined using photbleaching and electron scavenging methods. Maximum values of Get–= 2·2 are found at 60% w/w solute and G(sugar radicals)= 2·3 at this solute concentration. Photobleaching results in reaction of the trapped electrons with the sugar to give almost an equivalent yield of sugar radicals and makes this method, therefore, unreliable for determining Get–. Conversion of radiation induced electrons into hydrogen atoms using H2SO4 doubles G(sugar radicals) at 60% w/w solute. From the variations in et– and radical yields with carbohydrate concentration in acidic and neutral ices, an increase in the ‘glassiness’ of the ices can be monitored as the solute content is increased above ca. 40% w/w. An increase in the yield of et– occurs here due to an increase in the number of suitable traps. Optical absorption spectra of et– have been recorded at 77 K in frozen, aqueous D-glucose, D-fructose, and sucrose glasses; λmax. decreases linearly with increasing sugar concentration, giving by extrapolation λmax.(glassy ice)= 670–690 nm and λmax.(pure sugar glass)= 485, 505, and 516 nm for the three sugars.
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