Oxygen effect and influence of buffer on radiation-induced tritium cleavage from phage-T2-DNA-(methyl-3H) in aqueous solution.

The effect of gamma irradiation on tritium release into water (HTO) from phage T2-DNA-(methyl-3H) was studied in diluted aqueous solution. The influence of O2 and of citrate and phosphate buffer was investigated. In oxygenated solutions an enhancement ratio of 3 was found. From the linear dose yield relations G values were calculated. In the presence of N2O tritium release was doubled, whereas tritium release decreased with increasing citrate concentration. It has been concluded that the major precursor of this tritium release is the OH radical. This was substantiated by experiments using thymine-(methyl-3H) and dimethylsulfoxide.