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Updated: Jun 24, 2026

Exploring the Radical Nature of a Carbon Surface by Electron Paramagnetic Resonance and a Calibrated Gas Flow
Published on: April 24, 2014
Free radical generation in rosmarinic acid investigated by electron paramagnetic resonance spectroscopy
Katharina F Pirker1, Christopher W M Kay, Klaus Stolze
1Department of Environmental Research, Austrian Research Centers GmbH-ARC, Seibersdorf, Austria. katharina.pirker@arcs.ac.at
Abstract:
Free radical generation as a result of oxidation reactions of rosmarinic acid (RA), a caffeic acid ester with 3,4-dihydroxyphenyllactate, was investigated by electron paramagnetic resonance (EPR) spectroscopy using a variety of oxidation conditions. Limitations and possibilities of using the various methodologies to obtain information about the reaction chemistry of polyphenols are discussed. Three different spectra were detected dependent on the pH and oxidizing agent. Feasible structures for the observed radicals were tested by density functional theory (DFT) calculations and the results indicate that oxidation reactions can occur at both of the catechol groups.
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