Temporal Changes in Purity and Specific Activity of Tritium-Labeled 2,3,7,8-Tetrachlorodibenzo-p-dioxin:  Radiopurity Model for Toxicology

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 to...

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Bibliographic Details
Published in:Environmental science & technology 1999-10, Vol.33 (20), p.3558-3567
Main Authors: Fernandez, Joseph D, Cook, Philip M, Butterworth, Brian C, Bradbury, Steven P
Format: Article
Language:English
Subjects:
Animal, plant and microbial ecology
Applied ecology
AQUATIC ORGANISMS
Biological and medical sciences
BIOLOGY AND MEDICINE, APPLIED STUDIES
Characterization
CHEMICAL ANALYSIS
Chemicals
DIOXIN
Ecotoxicology, biological effects of pollution
ENVIRONMENTAL SCIENCES
Fish
Fresh water environment
Fundamental and applied biological sciences. Psychology
Gas chromatography
Impurities
Insects
Mass spectrometry
Radioactivity
Scientific imaging
TOXICITY
Toxicology
TRACER TECHNIQUES
Tritium
TRITIUM COMPOUNDS
WATER POLLUTION
Worms
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Summary: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 which reacted with the solvent, toluene. Formation of TriCDD and tolyl-TriCDDs, from both TCDD and tolyl-TCDDs, probably resulted from radiolysis-induced loss of a chlorine to form TriCDD free radicals which reacted with toluene. The measurement of S for [3H]TCDD by GC/MS was accurate and precise (±3%) because relative, rather than absolute, amounts of the analogues were determined. Changes in S over time were accurately modeled as a function of the conversion of each [3H]TCDD analogue to a solvent-TCDD analogue at a rate determined by 3H loss due to decay. Storage, purification, and use of tritiated chemicals for toxicology studies requires consideration of the 3H decay-related phenomena. For example, hydroxylated TCDD is an expected decay reaction product of [3H]TCDD in tissues and may be misidentified as a metabolite.
ISSN:0013-936X
1520-5851
DOI:10.1021/es990239j