Iron Fenton oxidation of 2'-deoxyguanosine in physiological bicarbonate buffer yields products consistent with the reactive oxygen species carbonate radical anion not the hydroxyl radical.

Product analysis from the iron Fenton oxidation of 2'-deoxyguanosine found reactions in bicarbonate buffer yield 8-oxo-2'-deoxyguanosine and spiroiminodihyantoin consistent with CO3˙-. Reactions in phosphate buffer furnished high yields of sugar oxidation products consistent with HO˙. These observations change the view of DNA oxidation products from the iron-Fenton reaction.