Effects of Light, Oxygen, and pH on the Absorbance of 2,2-Diphenyl-1-picrylhydrazyl

The absorbance of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) at 517 nm in methanol and acetone decreased by 20 and 35% for 120 min at 25 °C under light, respectively; in the dark it did not change significantly for 150 min. Decomposition of DPPH under 21% oxygen after 90 min under light was significantly...

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Bibliographic Details
Published in:Journal of food science 2003-03, Vol.68 (2), p.487-490
Main Authors: Ozcelik, B., Lee, J.H., Min, D.B.
Format: Article
Language:English
Subjects:
antioxidant activity measuring method
Antioxidants
DPPH
Food science
free radicals
Light
Oxygen
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Summary:The absorbance of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) at 517 nm in methanol and acetone decreased by 20 and 35% for 120 min at 25 °C under light, respectively; in the dark it did not change significantly for 150 min. Decomposition of DPPH under 21% oxygen after 90 min under light was significantly higher than that under 1% oxygen. Absorbance of DPPH in pH 4 buffer solution in methanol, and in pH 10 buffer solution in acetone, decreased by 55 and 80%, respectively, under light for 120 min. The evaluation of antioxidant activity by the changes of DPPH absorbance should be carefully interpreted since the absorbance of DPPH at 517 nm is decreased by light, oxygen, pH, and type of solvent in addition to the antioxidant.
ISSN:0022-1147
1750-3841
DOI:10.1111/j.1365-2621.2003.tb05699.x