High-energy ionizing radiation influence on the fragmentation of glutamine

Both experimentally, by using the mass-spectrometric technique, and theoretically, by applying Becke's three-parameter hybrid density functional approach, the yield of the ionic products of both single- and dissociative ionization of the glutamine molecule (C₅H₁₀N₂O₃) under high-energy (11.5 MeV) electron impact has been studied. The experimental mass spectra measured at different irradiation doses (i.e., 0, 5, 10, and 20 kGy) have been identified and analyzed. It has been shown that high-energy electrons cause irreversible changes in the structure of the molecule under study, accompanied by a transition to the zwitterionic/deprotonated form, which may cause a change in the fragment ion production at the interatomic distance variation. It has been shown that the yield of the low-mass fragments from the zwitterionic glutamine molecular structure may increase due to an increase in the isobaric ion yield.