Dioxins, Furans, and PCB Congeners

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Dioxin, Furan and Polychlorinated Biphenyl (PCB) Congeners are chlorinated biphenyl compounds that share a common toxicity mechanism. The analyses used to determine these compounds’ relative toxicity share common elements that differ from methods used for more traditional analytical determinations. The preferred methods for dioxins and related analyses use isotope dilution, high resolution gas chromatography/mass spectrometry (HRGC/HRMS). Concentrations are determined by measuring the ratio of the analyte to the appropriate isotopically labeled internal standard.

Holding Times for dioxins and related compounds are 30 days or longer for extraction and 40 days to a year for the analysis of the extract. These compounds are extremely stable and most published holding times are recommendations only.

Reporting Limits are determined from the lowest concentration used to calibrate each congener. These reporting limits are specified by the method and can be found on reverse of this page.

Detection Limits are calculated for each congener in each sample from the response and recovery of the appropriate labeled standard. The detection limits will depend on the matrix, the sample size and instrument performance. Detection limits are reported with each sample result and are usually much lower than the method reporting limits. It is very important to discuss any project-specific, detection limit requirements with the laboratory before the project begins.

With a HRGC/HRMS instrument, because the detection limits are calculated for each congener in each sample during each analytical run, the term MDL has no application.

Turn around times are usually longer for dioxin and related analyses. With our new Automated Solid Extractor, it is now possible to produce results for a solid sample in 48 - 72 hours after sample receipt. Cleanup procedures are also required before the extract can be analyzed. Our standard turn around time for these analyses is 21 days for the final report. Rush turn around times (3-7 days) are available upon request.

Matrix Spike/ Matrix Spike Duplicates are not required QC samples for these analyses. Recoveries are determined from isotope labeled internal standards. Lab control spikes are used to evaluate method consistency. MS/MSD samples may be run for additional project-specific QC. This must be requested in advance and are usually billed as separate samples.

Toxicity Equivalence Factors (TEFs) are used to assess the toxicity of dioxin and “dioxin-like” compounds relative to TCDD. These factors are multiplied by the concentration of the compound to determine the Toxicity Equivalence Quantity (TEQ). Most regulations cite the sum of the TEQ’s or total TEQ in a sample.

Second Column Confirmation of TCDF is required when TCDF is detected on the first column. Results from both columns will be included in the report, however, the results from the second column are used to evaluate the TCDF level in the samples and to determine the TEQ value for TCDF.

Over Range Samples are samples that have concentrations higher than the linear portion of the calibration curve. These results are flagged with an “E”. To bring the results within the calibration range, over range samples are diluted and re-analyzed. This will extend the turn around time for the final report by as much as a week.



Dioxin Furans PCBs

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Learn about Dioxin Testing...

Learn about Furan Testing...

Learn about Dioxin & Furan Testing...

Learn about PAH Testing...

Learn about PCB Congener Testing by the CLP Method...

Learn about Testing PCB Congeners & Aroclors...

Learn about Dioxin Cleanup Regions in the U.S....

Download Dioxin/Furan Conversion Table (Excel file)...