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Temporal Changes In Purity And Specific Activity Of Tritium-Labeled 2,3,7,8-Tetrachlorodibenzo-Ρ-Dioxin: Radiopurity Model For Toxicology, Steven P. Bradbury, Joseph D. Fernandez, Philip M. Cook, Brian C. Butterworth

Steven P. Bradbury

The specific activity (S) and radiopurity (R) of tritium labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin, [3H]TCDD, were measured by gas chromatography/mass spectrometry (GC/ MS) while attempting to accurately characterize TCDD doses received by invertebrates, fish, and fish embryos during several toxicology studies conducted over a 3 year period. The [3H]TCDD sample was found to consist of six TCDD analogues involving hydrogen, deuterium, and tritium substitution at the 1,6-dibenzo-p-dioxin carbon positions and a complex mixture of impurities (with and without tritium labels). Planar aromatic impurities were identified as tolyl- TCDD adducts and appeared to result from the decay of 3H radiolabels to produce TCDD carbocations …