Understanding the dosimetric powder EPR spectrum of sucrose by
identification of the stable radiation-induced radicals
H. Vrielinck,1 J. Kusakovskij,1,2 G. Vanhaelewyn,1 P. Matthys1 and F. Callens1
1
EMR research group, Dept. Solid State Sciences, Ghent University, Krijgslaan 281-S1, B-9000
Gent, Belgium
2 Vilnius University, Institute of Applied Research, Sauletekio av. 9-III, LT-10222 Vilnius,
Lithuania
Ionising radiation produces stable radicals in carbohydrates, like sugars, in concentrations
correlated with the radiation dose. Hence it can be used in EPR dosimetry. In particular
sucrose, the main component of table sugar, present in nearly every household and quite
radiation-sensitive, is considered as an interesting emergency dosimeter [1]. Sugarcontaining foodstuffs usually contain a mixture of sugars, all exhibiting their distinct EPR
signal with specific dose response, and overlapping in the total spectrum. Hence they can
also be used to detect irradiation [2]. The complexity of EPR spectra of radicals in sugars, as
a result of many hyperfine interactions, and the multi-compositeness of the spectra of
individual sugars complicate dose assessment and the improvement of protocols for control
and identification of irradiated sugar-containing foodstuffs using EPR. A thorough
understanding of the EPR spectrum of individual irradiated sugars is desirable when one
wants to reliably use them in a wide variety of dosimetric applications.
Recently, the dominant room temperature stable radicals in irradiated sucrose have been
thoroughly characterized in our lab using EPR, electron nuclear double resonance (ENDOR)
and ENDOR-induced EPR [3-5]. These radicals were structurally identified by comparing
their proton hyperfine and g tensors with the results of Density Functional Theory
calculations for test radical structures. In this contribution we use the spin Hamiltonian
parameters determined in these studies to simulate powder EPR spectra at the standard Xband (9.5 GHz), commonly used in applications, and at Q-band (34 GHz), rendering spectra
with higher resolution. The simulations indicate that the central part of the dosimetric
spectrum can be understood as arising from these dominant radicals, but as-yet unidentified
radicals also contribute in a non-negligible way.
1. T. Nakajima, Health Physics 1988, 55, p. 951.
2. EN-1307 Foodstuffs - Detection of irradiated food containing crystalline sugar by ESR
spectroscopy, http://ec.europa.eu/food/food/biosafety/irradiation/13708-2001_en.pdf
3. H. De Cooman, E. Pauwels, H. Vrielinck, A. Dimitrova, N. D. Yordanov, E. Sagstuen, M. Waroquier
and F. Callens, Spectrochim. Acta A 2008, 69, p. 1372.
4. H. De Cooman, E. Pauwels, H. Vrielinck, E. Sagstuen, F. Callens and M. Waroquier, J. Phys.
Chem. B 2008, 112, p. 7298.
5. H. De Cooman, E. Pauwels, H. Vrielinck, E. Sagstuen, S. Van Doorslaer, F. Callens, and M.
Waroquier, Phys. Chem. Chem. Phys. 2009, 11, p. 1105.