ELECTRON-SPIN-RESONANCE STUDY OF SPIN-TRAPPED RADICALS FROM GAMMA-IRRADIATION OF GLUCOSE OLIGOMERS

Radicals produced in aqueous solution by gamma irradiation of the five first glucose oligomers were trapped using 2‐methyl‐2‐nitrosopropane (MNP) and separated by high‐performance liquid chromatography. The electron spin resonance (ESR) spectra were analysed on a microcomputer with a general interactive simulation program (VOYONS). The ESR coupling constants of five radical adducts, which were found in all the oligomers, are reported. A comparison with the coupling constants previously obtained from α‐D‐glucopyranosyl,‐0‐methyl‐α‐D‐glucopyranose, O‐α‐D‐glucopyranosyl‐(1 →4)‐α‐D‐glucopyranose or polyols, irradiated in the liquid phase or in the powder state, provides new information on the chemical structures of the radicals radioinduced in glucose oligomers. As the powder ESR spectra and the main radiolytic products from the gamma‐irradiated oligomers have been found to be comparable to those from irradiated starches, this work is the first step in the elucidation of the radiolysis mechanism of starch. Copyright © 1990 John Wiley & Sons, Ltd.