Trichloroethylene radicals generated by ionizing radiation. An EPR/spin trapping study.

Trichloroethylene (TCE) was exposed in the presence of the spin trap N-tert-butyl-α-phenyl nitrone (PBN, 0.1 M) to ionizing radiation from two different sources in an attempt to determine the origin of the spin-trapped radicals generating the EPR spectra in precision cut liver slices. TCE samples were irradiated with 18 MeV electrons to a total dose of 1000 Gy in a linear accelerator (LINAC) or exposed to 60Co γ-rays to total doses of 100 Gy and 1000 Gy. The results show that three PBN adducts were generated during the LINAC radiations. Two of these spin adducts correspond to the addition of carbon-centered radicals to PBN, and the third adduct is consistent with a decomposition product of PBN. The predominant carbon- entered radical yields a PBN adduct that is more stable, persists for over 24 h and has identical hyperfine coupling constants (a N=1.61 mT, aHβ=0.325 mT) to the PBN adduct obtained when precision-cut liver slices were exposed to TCE. Gamma radiation (100 Gy) of TCE yields PBN adducts with l...