Inhibitory Effects by Antioxidants on the Oscillations of the Briggs-Rauscher Reaction in Mixed EtOH/H2O Medium

✍ Scribed by Rinaldo Cervellati; Kerstin Höner; Stanley D. Furrow; Francesco Mazzanti

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: German
• Weight: 189 KB
• Volume: 85
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/1522-2675(200208)85:8<2523::aid-hlca2523>3.0.co;2-e

✦ Synopsis

The Briggs-Rauscher (BR) oscillating reaction in mixed 20% EtOH/H 2 O (v/v) medium is studied together with the inhibitory effects by the addition of hydroalcoholic solutions of antioxidants on its oscillatory regime. As in aqueous BR mixtures, the inhibitory effect consists of an immediate cessation of oscillations, an inhibitory time that linearly depends on the concentration of the antioxidant added, and subsequent regeneration of oscillations. The effects of several water-insoluble and water-soluble antioxidants were investigated: at a parity of concentration of antioxidant added, inhibition times in the mixed EtOH/H 2 O medium are 2 ± 3 times lower than those reported previously in aqueous solution. However, the mechanism of the BR reaction, as far as that of the inhibitory effect, seems to be the same in either aqueous or mixed medium. The findings reported and discussed here are an indication that the analytical procedure to assess the activity of free radical scavengers based on the BR reaction can be extended to lipophilic antioxidants.