Fluorescence Detection of Free Radicals by Nitroxide Scavenging
- 1 January 1990
- journal article
- research article
- Published by Taylor & Francis Ltd in Free Radical Research Communications
- Vol. 10 (1-2), 119-121
- https://doi.org/10.3109/10715769009145941
Abstract
The fluorescence quantum yield of 4-(1-napthoyloxy)-2,2,6,6-tetramethylpiperidine-l-oxyl (I) in acetonitrile and hexane is 55 and 30-fold lower, respectively, than those of diamagnetic analogs. Experiments described herein demonstrate that this property makes possible the fluorescence detection of radical scavenging reactions in which the paramagnetic nitroxide-substituted naphthalene is converted to a diamagnetic N-alkoxy derivative. 2-Cyanopropyl free radicals were generated by the thermal decomposition of azobisisobutyronitrile (AIBN) in cyclohexane or in acetonitrile containing 1. The fluorescence intensity of the sample increased proportionally to the decrease in its ESR signal intensity, indicating the conversion of the paramagnetic nitroxide to the diamagnetic product. The linear relationship between the increase in fluorescence intensity and decrease in ESR signal intensity shows that the changes in the fluorescence intensity can serve as a sensitive means for optically detecting radicals.Keywords
This publication has 3 references indexed in Scilit:
- Chemically mediated fluorescence yield switching in nitroxide-fluorophore adducts: optical sensors of radical/redox reactionsJournal of the American Chemical Society, 1988
- Determination of free radicals in polymer films by electron spin resonance spectrometryAnalytical Chemistry, 1983
- Determination of the Antioxidant Capacity of New and Used Lubricants: Method and ApplicationsIndustrial & Engineering Chemistry Product Research and Development, 1978