Inhibitory Effects by Ascorbic Acid on the Oscillations of the BriggsRauscher Reaction

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

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: German
• Weight: 161 KB
• Volume: 87
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200490068

✦ Synopsis

Abstract

The BriggsRauscher oscillating reaction (in batch mode) has been shown to be sensitive to various antioxidants, some of which cause cessation of oscillations for a period of time, before a restart occurs. The length of time before oscillations restart is related to the type of antioxidant and its concentration. Procedures have been devised to apply this method as a tool for measuring antioxidant activities of pure compounds and of extracts of natural sources. The antioxidant activity in the BriggsRauscher system has been generally related to the reaction of an antioxidants with hydroperoxy radicals (HOO^.^) present in the oscillating system. Thereby, at low concentration (<2×10^−4^ M), ascorbic acid is known to have a little effect on the reaction. However, there is a concentration range, where a nearly linear relation is observed between ascorbic acid concentration and inhibition time. We were able to model this type of inhibition by the reducing power of ascorbic acid without invoking a reaction with HOO^.^.