Naslov
Availability of oxygen in radiation-induced peroxidation of unsaturated fatty acids.

Autori
Katušin-Ražem, Branka ; Ražem, Dušan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
10th "Tihany" Symposium on Radiation Chemistry - Book of Abstracts / - Budimpešta : Hungarian Chemical Society, 2002, P-35

Skup
10th "Tihany" Symposium on Radiation Chemistry

Mjesto i datum
Sopron, Mađarska, 31.08.2002. - 05.09.2002

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Sažetak
Radiation – induced chain peroxidation of polyunsaturated fatty acids (PUFA) critically depends on the availability of oxygen. An inverse square-root dependence of the radiation chemical yield of hydroperoxide, G(LOOH), on the dose rate is usually taken as a criterion of the chain mechanism of the reaction; the proportionality factor contains another important quantity, oxidizability. However, this criterion is valid not only under adequate oxygenation, but also under hypoxic conditions, where inverse square-root dependence also holds, with the proportionality factor assuming a different meaning. We suspect that inadequate oxygenation might be the cause of a significant scatter of data on the oxidizability of PUFA in the literature. In our investigations of radiation peroxidation of PUFAs we measured G(LOOH) values as function of surface-to-volume ratio. Oleic (OlH), linoleic (LiH), linolenic (LinH) and arachidonic (ArH) acid were irradiated by 60Co gamma rays at various dose rates without bubbling, and LOOH were analyzed by a spectrophotometric method based on ferric thiocyanate. As the surface-to-volume ratio increased, the G(LOOH) values also increased to approach the values obtained in PUFAs bubbled with oxygen during irradiation. The largest volumes which could be adequately oxygenated only by diffusion at a relatively high rate of oxygen consumption (at the dose rate 5.5 Gy/s) were 7, 6 and 5 mg of LiH, LinH and ArH, respectively. Penetration depths of oxygen were calculated as 0.068, 0.062 and 0.050 cm in LiH, LinH and ArH, respectively. These penetration depths correspond to 9, 7 and 5 mg of LiH, LinH and ArH, respectively, which is in reasonable agreement with the experiment.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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