EPR studies of gamma-irradiated L-alanine ethyl ester hydrochloride, L-arginine and alanyl-L-glutamine

gamma-Irradiated powders of L-alanine ethyl ester hydrochloride (LAES), L-arginine (LA) and alanyl L-glutamine (ALG) were investigated at room temperature by electron paramagnetic resonance (EPR). The observed species in LAES and LA are attributed to the CH3CHCOOC2H5 and CH2CHNHCNHNH2 radicals, respectively. In the case of ALG, the EPR signal is attributed to the CH2CNHCOOH. Hyperfine structure constants and g-values are determined for these three radicals. It is found that these results are in good agreement with those of previous experimental and theoretical studies. The unirradiated samples were found to display no EPR signal.