Method 8280B Water
Polychlorinated Dibenzodioxins (PCDDs) and Polychlorinated Dibenzofurans (PCDFs) by High Resolution Gas Chromatography/Low Resolution Mass Spectrometry (HRGC/LRMS)
This method is for the determination of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-tetrachlorinated dibenzofuran (2,3,7,8-TCDF), and the 2,3,7,8-substituted penta-, hexa-, hepta-, and octachlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in water at part-per-trillion (ppt) concentrations. The sample is filtered prior to extraction to remove particulates. The filtrate is extracted with methylene chloride using a separatory funnel, liquid-liquid extractor or solid phase extraction (SPE). The particulates are extracted separately with toluene using a Soxhlet extractor. After extraction C13-labeled standards are spiked into the sample to monitor clean-up efficiency. Clean-up options for the extracts are an acid-base wash, gel permeation, alumina, silica gel and Florisil column clean-ups. After clean-up the extract is concentrated and analyzed by high resolution gas chromatography/low resolution mass spectrometry (HRGC/LRMS).
This is an isotope dilution method.
A calculation of the TEQ (toxicity equivalent concentration) is done for each sample using international toxicity equivalency factors (TEFs). A high TEQ, greater than 7 ppt, will require analysis on a second GC column unless 2,3,7,8-TCDF is separated from its closest eluting isomers from analysis on the primary column.
This method replaces Methods 8280 and 8280A.