The Radiation Chemistry of Aqueous Solutions of Ammonium and Sodium Cyanides in the Megarad Dose Range

Oxygen-free aqueous solutions of 0.1 M ammonium and sodium cyanides were exposed to large doses of⁶⁰ Co γ rays. Radiation-chemical yields were determined for the decomposition of cyanide molecules, as were the total amount of nitrogen in nonvolatile nitrogen-containing radiolytic products, the free ammonia, and the yields of several amino acids released on acid hydrolysis of irradiated samples. Positive biuret reaction was found and its intensity used for an estimation of amide bond yields. Up to 18% of the nitrogen from nonvolatile radiolytic products appears in the amide bond, and up to 14% appears in natural amino acids. The origin of peptidic material is attributed to the polymerization initiated by cyano radicals produced in reactions of cyanides with OH, H, and <tex-math>$e{}_{{\rm aq}}{}^{-}$</tex-math> species from radiolyzed water.