Interlaboratory comparison of PCDF and PCDD analysis in transformers and capacitors dioxin 88

Abstract The major object of the study was to evaluate and upgrade methods of analysis; analysis of field samples was an important secondary output. The study involving five participating laboratories, was conducted in two phases. Phase I was designed to locate glaring discrepancies in the techniques, and Phase II to statistically improve the accuracy of results from the different laboratories on a series of unknown samples. The impetus for the studies has been the wide range of toxicities (4–5 orders of magnitude) seen for the individual compounds in animal tests, and the difficulty of quantitatively analyzing for some of these chemically similar compounds of dissimilar toxicity, often in the presence of a great excess of PCBs. This study suggests that there is no strongly preferred analytical procedure among those using a combination of extraction/chemical cleanup, gas chromatography, and mass spectrometry for measuring compound-specific concentrations of PCDF and PCDD. In the field samples, the maximum concentration for 2, 3, 7, 8-Tetra-CDD was 32 ng/g and the maximum concentration of the combination of 2,3,7,8-tetra-CDF + 2,3,4,8-tetra-CDF was 459 ng/g. The highest concentration measured was for one sample of the much less environmentally significant octachlorinated dibenzofuran at 65,000 ng/g. These concentrations are reported with a statistical 95% confidence level.