Free radical-induced cross-linking of polydeoxythymidylic acid in deoxygenated aqueous solution.

Radiation-generated hydroxyl radicals and hydrogen atoms were shown to induce the cross-linking of polydeoxythymidylic acid (mol X wt approximately 170 000) in N2O-saturated acqueous solution. The irradiated samples were hydrolysed with formic acid and then analysed by high performance liquid chromatography. Products were isolated and subsequently characterized by capillary gas chromatography-mass spectrometry. The presence of previously described monomeric thymine products was also shown. Yields were determined and mechanisms of formation were described for the products.