Resumo

MURILLO PULGARIN, José Antonio; GARCIA BERMEJO, Luisa Fernanda  e  CARRASQUERO-DURAN, Armando. Application of the luminol-perborate-co(II) chemiluminescence in the teaching of the structure-reactivity relationships of organic molecule. Paradígma [online]. 2013, vol.34, n.2, pp.93-108. ISSN 1011-2251.

A flow injection analysis (FIA) methodology has been developed for the estimation of the radical scavenging activity of phenolic compounds as a measure of their antioxidant activity, which can be employed in the organic physical chemistry courses at university level. The method was based on the inhibition of the luminol chemiluminescence (CL) induced by the oxygen reactive species formed during the Co(II) catalyzed perborate decomposition. At the optimum operational conditions, the antiradical activity is measured in terms of the CI₅₀ (the phenolic concentration required to reduce in a 50 % the CL emission in the absence of antiradical compounds). For this purpose the percentage of CL inhibition (% Inh) against the sample concentration was plotting. The method was evaluated employing caffeic acid, hydroquinone, tymol, salycilic acid, phenol, resorcinol, catechol and p-hydroxybezaldehyde.  Results showed that the caffeic acid and hydroquinone had the highest antiradical activities which were dependent on the molecular structures and reactivity of the phenols evaluated. The method resulted adequate for a fast, simply and accurate estimation of the antioxidant activity of the phenolic compounds present in natural or artificial sources.

Palavras-chave : FIA; Chemiluminescence; antiradical activity; reactivity; phenolics.

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