engleski

Elementary reaction steps in radiation induced hydroperoxidation of unsaturated fatty acids

Chain oxidation of unsaturated fatty acids (LH): oleic (OlH), linoleic (LiH), linolenic (LinH) and arachidonic (ArH) was initiated by 60-Co gamma rays at various dose rates. The measured radiation chemical yields of respective fatty acid hydroperoxides, G(LOOH), were iversely proportional to the square root of the dose rate, P, indicating a chain mechanism with bimolecular termination of propagating radicals (Eq. 1), where kp and kt are propagation and termination rate constants respectively, and G(L') is the radiation chemical yeild of initiating alkyl radicals (L'). G(L') was determined by the inhibitor method using alpha-tocopherol and measuring inhibiton dose, Dinh (Eq. 2). From these measurements respective oxidizabilities and kinetic chain lengths could be calculated. However, individual values of kp and kt could not be determined from a steady-state radiolysis data. Absolute values of the termination rate constants were measured independently, by the method of intermittent irradiation, for which a special apparatus was constructed. Thus absolute values of kp and kinh could be calculated (Table 1).

nije evidentirano

nije evidentirano