The radiation chemistry of cystamine sulphate

Abstract

Irradiation of aqueous cystamine solutions with X-rays (230 kV; 15 mA), in the presence of oxygen, results in the formation of taurine, hydrogen peroxide, and traces of hydrogen sulphide. When oxygen is removed from the solution, hydrogen sulphide formation increases noticeably, while yields of taurine and peroxide both decrease. The dependence of the radiation yields on pH and on the initial concentrations of cystamine, hydrogen peroxide, and dissolved oxygen have been studied. The primary action upon the cystamine molecule most probably is attack by ·OH with contributions from attack by ·H and by ·O₂H under favourable conditions. Hydrogen peroxide, ·O₂^– and e_aq.^– probably do not react readily with cystamine. The results suggest that the successful radiation-protective properties of cystamine may be due to its dual capacity of radical acceptor and oxygen scavenger.