Development of analytical methods for determination of dioxins: Advantages of tritium-labeled TCDD and carbon 14-labeled OCDD

Malisch, Rainer; Metschies, M.

doi:10.1016/0045-6535(94)90348-4

Cited by 4 publications

(1 citation statement)

References 3 publications

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“…Tritium ( 3 H) labeled compounds are often used in toxicology studies because of analytical advantages that include rapid sample throughput associated with liquid scintillation counting (LSC), the ability to analyze a large number of samples at low cost, and low limits of detection due to high specific activity. For example, investigations of the toxicity (1, 2), pharmacokinetics (3)(4)(5), and metabolism (6-10) of 2,3,7,8tetrachlorodibenzo-p-dioxin (TCDD), in addition to analytical methods, development for polychlorinated dibenzo-pdioxins and dibenzofurans (11) have used 3 H-labeled prepa-rations to measure concentrations of TCDD without the need for slower, more expensive gas chromatography/mass spectrometry (GC/MS) analysis. In aquatic toxicology, [ 3 H]TCDD has been especially useful for the determination of bioconcentration factors (12,13) and delivered dose to small fish (12,14) and/or early life stages of fish (15)(16)(17)(18)(19) that require analysis of tissue samples too small for use of radiocarbon ( 14 C) labeled TCDD with its lower specific activity.…”

Section: Introductionmentioning

confidence: 99%

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

Fernandez

Cook

Butterworth

et al. 1999

Environ. Sci. Technol.

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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.

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