Electron paramagnetic resonance characterization of gamma irradiation damage centers in powder of L-(+)-tartaric acid, N-acetyl-L-alanine and 1-methyl-L-histidine

Abstract

The electron paramagnetic resonance (EPR) of γ-irradiated powders of l-(+)-tartaric acid, N-acetyl-l-alanine and 1-methyl-l-histidine were investigated at room temperature. Radiation damage centers are attributed to HOOCCH(OH)Ċ(OH)COOH, CH₃ĊHCOOH and ‒CH₂ĊHCOOH radicals. The spectra were computer-simulated. Hyperfine structure constants and g-values were determined for these three radicals. The unirradiated samples showed no EPR signal. Some spectroscopic properties and suggestions concerning the possible structure of the radicals are discussed in this paper.

Keywords:

• EPR
• free radicals
• gamma irradiation
• amino acid derivatives

Acknowledgements

This work was supported by Grant No. EFBAP2009-5 of the Research Fund of Adıyaman University (ADÜYAP).