SW-846 Update V 4430 - 1 Revision 1 

October 2012 

METHOD 4430 

SCREENING FOR POLYCHLORINATED DIBENZO-p-DIOXINS (PCDDs) AND 

POLYCHLORINATED DIBENZOFURANS (PCDFs) IN SOILS AND SEDIMENTS 

USING AN ARYL HYDROCARBON RECEPTOR-BASED PCR ASSAY 

 SW-846 is not intended to be an analytical training manual. Therefore, method 

procedures are written based on the assumption that they will be performed by analysts who are 

formally trained in at least the basic principles of chemical analysis and in the use of the subject 

technology. 

 In addition, SW-846 methods, with the exception of required method use for the analysis 

of method-defined parameters, are intended to be guidance methods which contain general 

information on how to perform an analytical procedure or technique which a laboratory can use 

as a basic starting point for generating its own detailed standard operating procedure (SOP) 

either for its own general use or for a specific project application. The performance data 

included in this method are for guidance purposes only, and are not intended to be and must not 

be used as absolute QC acceptance criteria for the purposes of laboratory accreditation. 

 

1.0 SCOPE AND APPLICATION 

For a summary of changes in this version, please see Appendix A at the end of this 

document. 

1.1 This method is a screening procedure for polychlorinated dibenzo-p-dioxins 

(PCDDs) and polychlorinated dibenzofurans (PCDFs) in soils and sediments. This method uses 

a commercially-available aryl hydrocarbon receptor (AhR)-based polymerase chain reaction 

(PCR) assay. The AhR-PCR assay screens samples by their toxicity equivalent quotient (TEQ) 

by responding to individual PCDD/PCDF congeners in approximate correlation to their toxicity 

equivalent factors (TEFs). The TEQ measured by the AhR-PCR assay is the sum of the 

response from the individual congeners. See Table 2 for a detailed list of response factors for 

individual PCDD/PCDF congeners. More information about the AhR-PCR assay can be found 

at www.eichrom.com/dioxin/products. 

1.2 The AhR-PCR assay employs AhR proteins extracted from mammalian cells to 

bind PCDD/PCDFs. Upon binding PCDD/PCDFs, the AhR forms an activated receptor complex 

with an aryl hydrocarbon nuclear translocator (ARNT) and a specific DNA response element 

(DRE). This activated receptor complex is captured onto a microwell in a 96-well plate and 

isolated from unreacted AhR, ARNT and DRE by washing on a 96-well plate washer. The level 

of PCDD/PCDF contamination is then measured indirectly by amplifying and measuring the 

DRE using real time PCR. Since the interaction of the AhR with individual PCDD/PCDF 

congeners is proportional to the TEF values of the individual PCDD/PCDF congeners, the 

response measured by the AhR-PCR assay correlates very well with the TEQ of the sample. 

1.3 The AhR-PCR assay and the associated sample preparation method outlined in 

this document provide a technique for the estimation of the total PCDD/PCDF TEQ. The 

method will not provide concentrations of individual PCDD/PCDF congeners, as the individual 

congeners are not separated during the sample preparation. During the sample preparation, 

the PCDD/PCDFs are isolated as a group from potentially interfering compounds such as 

polychlorinated biphenyls (PCB) and polynuclear aromatic hydrocarbons (PAH). A complete list 

of compounds which have been identified to have significant response on the AhR-PCR assay 

is provided in Table 2. 
SW-846 Update V 4430 - 2 Revision 1 

October 2012 

1.4 The AhR-PCR assay responds to PCDD/PCDF congeners in proportion to their 

concentration and TEF value. However, the response factors for individual PCDD/PCDF 

congeners on the AhR-PCR assay are not identical to the TEF values assigned by the World 

Health Organization (WHO). Therefore, variation in the accuracy among samples may occur 

solely because of variability in congener composition. A comparison of AhR-PCR response 

factors and WHO TEF values is provided in Table 2. 

1.5 This method details a single extraction technique, pressurized fluid extraction 

(PFE), and sample preparation method which has been shown to effectively extract the 

PCDD/PCDFs from soil and sediment samples and isolate the PCDD/PCDFs from most 

interfering classes of compounds. Other extraction methods, solvent systems or sample cleanup methods may be used, provided adequate performance of these methods is demonstrated 

for the analytes of interest from the matrix of interest. 

1.6 The limit of detection submitted by the manufacturer of this testing product is 0.4 

pg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). This detection limit is provided as 

guidance only, and the limit achievable by a user for a given sample will be dependent on 

several factors including the type of sample matrix. 

 1.7 Prior to employing this method, analysts are advised to consult the base method 

for each type of procedure that may be employed in the overall analysis (e.g., Methods 3500, 

3600, 4000, 5000, and 8000) and the manufacturer’s instructions for additional information on 

quality control procedures, development of QC acceptance criteria, calculations, and general 

guidance. Analysts also should consult the disclaimer statement at the front of the manual and 

the information in Chapter Two for guidance on the responsibilities of the analyst for 

demonstrating that the techniques employed are appropriate for the analytes of interest, in the 

matrix of interest, and at the levels of concern. 

 In addition, analysts and data users are advised that, except where explicitly specified in a 

regulation, the use of SW-846 methods is not mandatory in response to Federal testing 

requirements. The information contained in this method is provided by EPA as guidance to be 

used by the analyst and the regulated community in making judgments necessary to generate 

results that meet the data quality objectives for the intended application. 

1.8 This method is restricted to use by, or under the supervision of, personnel 

appropriately experienced and trained in the use of general laboratory techniques including 

sample extraction, column chromatography and polymerase chain reaction (PCR). Each 

analyst must demonstrate the ability to generate acceptable results with this method. 

2.0 SUMMARY OF METHOD 

2.1 Detailed sample preparation and analysis procedures for this method are available 

in the manufacturer’s literature at www.eichrom.com/dioxin/products. A brief description of the 

key steps is provided below. 

2.2 Diatomaceous earth is added to the dry sample and mixed. The sample is then 

extracted using pressurized fluid extraction (PFE). 

2.3 Following PFE, the solvent is exchanged to hexane, and the PCDD/PCDFs are 

isolated from interfering compounds by column chromatography using commercially available 

silica gels and Florisil®. The PCDD/PCDFs are recovered in 50% methylene chloride:hexane. 

The sample is concentrated and redissolved in heptane. 
SW-846 Update V 4430 - 3 Revision 1 

October 2012 

2.4 An accurately measured volume of blank, sample, standard or recovery standard 

in heptane is added to a glass vial containing a mixture of AhR, ARNT and DRE and mixed for 

one hour. 

2.5 An accurately measured volume of the AhR, ARNT, DRE that has been 

equilibrated with blank, sample, standard or recovery standard for one hour is then added to a 

plastic microwell and mixed for 30 min. PCDD/PCDF-AhR-ARNT-DRE complexes bind to the 

walls of the microwell, and excess AhR, ARNT and DRE are removed by rinsing on a 96-well 

plate washer. 

2.6 PCR reagents are added to the microwell and the amount of DRE, which is 

proportional to the TEQ of the sample, is measured using PCR. The response from the PCR is 

related to TEQ by a dose-response curve generated from 2,3,7,8-TCDD standards. The PCR 

can analyze up to 38 samples in duplicate, with blanks, standards and recovery standards 

simultaneously in 90 min. 

3.0 DEFINITIONS 

 See the glossary at the end of this method for procedure-specific terms. Also, refer to 

Chapter One, Methods 8280 and 8290, and the manufacturer’s instructions for definitions that 

may be relevant to this procedure. 

4.0 INTERFERENCES 

4.1 Solvents, reagents, glassware and other sample processing hardware may yield 

artifacts and/or interferences to sample analysis. All of these materials must be demonstrated 

to be free from interferences under the conditions of the analysis by analyzing method blanks. 

Specific selection of reagents and purification of solvents by distillation in all-glass systems may 

be necessary. Refer to each method to be used for specific guidance on quality control 

procedures and to Chapter Four and Method 8290 for general guidance on the cleaning of 

glassware. 

4.2 The AhR used in this method binds to the seventeen PCDD/PCDF congeners with 

established TEF values, and other aryl hydrocarbon compounds, such as PCBs, PAHs, 

brominated and mixed brominated/chlorinated dibenzo-p-dioxins and furans, PCDD/PCDF 

congeners without established TEF values and other compounds similar in structure to 2,3,7,8-

TCDD. The highest response is observed for 2,3,7,8-TCDD and compounds of similar structure 

and degree of chlorination. A complete list of compounds for which the response of the AhRPCR assay has been observed is given in Table 2. 

4.3 The AhR used in this method binds to PCDD/PCDF and similar molecules based 

on structure, not mass. Therefore, 13Carbon- or other stable isotope-labeled standards are 

detected to the same degree as native compounds. These labeled standards cannot be used 

as internal standards with this method. 

4.4 High levels (106

 x that of the desired analyte) of selected PAH compounds and 

high molecular weight aliphatic hydrocarbons have been shown to inhibit the response of the 

AhR-PCR assay. However, it is unlikely that high levels of these compounds will remain with 

the PCDD/PCDF fraction if the sample preparation instructions provided by the manufacturer 

are followed. 
SW-846 Update V 4430 - 4 Revision 1 

October 2012 

5.0 SAFETY 

5.1 This method does not address all safety issues associated with its use. The 

laboratory is responsible for maintaining a safe work environment and a current awareness file 

of OSHA regulations regarding the safe handling of the chemicals listed in this method. A 

reference file of material safety data sheets (MSDS) should be available to all personnel 

involved in these analyses. 

5.2 The AhR-PCR assay should only be used by properly trained personnel in an 

appropriate laboratory environment. Personnel should wear appropriate personal protective 

equipment, including safety glasses, lab coat and gloves. 

5.3 WARNING: PCDD/PCDF standards, solutions containing PCDD/PCDFs and 

potentially contaminated samples should be treated as hazardous materials. 

5.4 Handle all organic solvents (toluene, acetone, hexane, heptane and methylene 

chloride) in a fume hood. 

5.5 Silica gels and Florisil should be treated as respiratory hazards and treated with 

the appropriate care. 

5.6 Silica gels impregnated with sulfuric acid, potassium hydroxide and silver nitrate 

should be treated with care as they can cause skin irritation, discoloration and/or burns. 

5.7 Some test components are stored in freezers (-20 oC and -80 oC). Care should be 

taken to avoid direct contact of frozen components with skin. 

6.0 EQUIPMENT AND SUPPLIES 

6.1 This section does not list all common laboratory glassware (e.g., beakers and 

flasks). A complete list of the equipment and supplies can be found in the manufacturer’s 

literature (www.eichrom.com/dioxin/products). 

6.2 The AhR-PCR assay requires a real-time PCR instrument with FAM and ROX 

detection capabilities. Please see the manufacturer’s literature for a complete list of compatible 

models. 

6.3 Other significant equipment required for the AhR-PCR assay includes a 96-well 

platewasher (Biotek Elx50 or equivalent), a 96-well plateshaker (Heidolph Titramax 1000 or 

equivalent), a refrigerator/freezer (≤6 oC/-20 oC) and a -80 oC freezer (or liquid nitrogen vial 

storage Dewar) for storage of the test kit components. 

6.4 The manufacturer will supply or specify equipment, apparatus and materials 

necessary for the successful completion of the test. Do not mix the equipment, supplies or 

reagents from other test kits. The AhR-PCR assay contains reagents that are evaluated by the 

manufacturer on a lot to lot basis. Do not mix the reagents from multiple lots, unless expressly 

allowed by the manufacturer. 

6.5 Incorporation of apparatus for the capture of evaporated solvents during 

concentration procedures may be required by Federal, State or local municipality regulations 

that govern air emissions of volatile organics. EPA recommends the incorporation of this type of 
SW-846 Update V 4430 - 5 Revision 1 

October 2012 

reclamation system as a method to implement an emissions reduction program. Solvent 

recovery is a means to conform with waste minimization and pollution prevention initiatives. 

7.0 REAGENTS AND STANDARDS 

7.1 Reagent-grade or pesticide-grade chemicals must be used in all tests. Unless 

otherwise indicated, it is intended that all reagents conform to the specifications of the 

committee of Analytical Reagents of the American Chemical Society, where such specifications 

are available. Other grades may be used, provided it is first ascertained that the reagent is of 

sufficiently high purity to permit its use without lessening the accuracy of the determination. 

Reagents should be stored in glass to prevent the leaching of contaminants from plastic 

containers. 

7.2 Extraction solvents -- This method has been validated using a 3:7 mixture of 

acetone and toluene for the extraction solvent and a pressurized fluid extraction system. Other 

solvent systems or another extraction apparatus may also be used provided that they have 

been shown to provide reproducibly high recovery of the analytes of interest from the matrix of 

interest. The choice of extraction solvent and apparatus will depend on the analytes of interest 

and the matrix of interest, and no single solvent or apparatus is universally applicable to all 

analytes or matrices. Whatever solvent system and apparatus is employed, including those 

specifically listed in this method, the analyst must demonstrate adequate performance for the 

analytes of interest, at the levels of interest, from the matrix of interest. See Sec. 9.2.1 of this 

method for more information about how to demonstrate adequate performance. . 

 7.3 Detailed information on reagent requirements is given in the manufacturer’s 

literature (www.eichrom.com/dioxin/products). Do not mix the equipment, supplies or reagents 

from different testing products or different lots of the AhR-PCR assay. Store all reagents and 

standards according to the manufacturer’s instructions, and discard any reagents that are past 

the expiration date assigned by the manufacturer. 

8.0 SAMPLE COLLECTION, PRESERVATION AND STORAGE 

 Sample collection, preservation and storage requirements may vary by EPA program and 

may be specified in a regulation or project planning document that requires compliance 

monitoring for a given contaminant. Where such requirements are specified in the regulation, 

follow those requirements. In the absence of specific regulatory requirements, use the following 

information as guidance in determining the sample collection, preservation and storage 

requirements. 

8.1 The AhR-PCR assay requires small sample masses (typically 5-10 g). Sample 

collection procedures should ensure that the sample is representative of the source. The 

distribution of PCDD/PCDFs in the sample can be heterogeneous. Samples should be 

homogenized to ensure that any subsamples are representative of the whole sample. Water 

content should be low enough to avoid standing water in the sample containers and ideally 

should be removed before homogenizing and subsampling. 

8.2 Sample extracts are stable for up to three months when refrigerated (≤6 oC) and 

stored in tightly sealed vials. Longer storage times may be possible if validated with 

performance data. 

8.3 Store all test kit components as outlined in the manufacturer’s literature. 
SW-846 Update V 4430 - 6 Revision 1 

October 2012 

8.4 Some components must be thawed before use. Unless otherwise instructed by the 

manufacturer, thaw components immediately prior to use to near room temperature. Do not use 

hot water to thaw components as this can lead to decreased performance of the test. 

8.5 Do not use test kits or components after the expiration date. 

8.6 Do not use test kit components with components from a different lot of the test kit 

or with components from test kits from different manufacturers. 

9.0 QUALITY CONTROL 

9.1 Refer to Chapter One for guidance on quality assurance (QA) and quality control 

(QC) protocols. When inconsistencies exist between QC guidelines, method-specific QC 

criteria take precedence over both technique-specific criteria and those criteria given in Chapter 

One, and technique-specific QC criteria take precedence over the criteria in Chapter One. Any 

effort involving the collection of analytical data should include development of a structured and 

systematic planning document, such as a Quality Assurance Project Plan (QAPP) or a Sampling 

and Analysis Plan (SAP), which translates project objectives and specifications into directions 

for those that will implement the project and assess the results. Each laboratory should 

maintain a formal quality assurance program. The laboratory should also maintain records to 

document the quality of the data generated. All data sheets and quality control data should be 

maintained for reference or inspection.

9.2 Refer to Methods 3500, 3600, 3620 and 3630 for QC procedures to ensure the 

proper operation of the various extraction and sample preparation techniques. Any more 

specific QC procedures provided in this method will supersede those noted in Methods 3500, 

3600, 3620 or 3630. 

 9.2.1 Initial demonstration of proficiency 

 

Each laboratory must demonstrate initial proficiency with each sample preparation 

and determinative method combination it utilizes by generating data of acceptable 

accuracy and precision for target analytes in a clean matrix. At a minimum, such a 

demonstration will encompass the initial demonstration of proficiency described in method 

3500, using a clean reference matrix. The laboratory must also repeat the demonstration 

of proficiency whenever new staff members are trained or significant changes in 

instrumentation are made. See Method 8000D, Sec. 9.3 for information on how to 

accomplish a demonstration of proficiency. 

9.3 Initially, before processing any samples, the analyst should demonstrate that all 

parts of the equipment in contact with the sample and reagents are interference-free. This is 

accomplished through the analysis of a method blank. As a continuing check, each time 

samples are extracted, cleaned up, and analyzed, and when there is a change in reagents, a 

method blank should be prepared and analyzed for the compounds of interest as a safeguard 

against chronic laboratory contamination. 

9.4 Any method blanks, matrix spike samples, or replicate samples should be 

subjected to the same analytical procedures (Sec. 11.0) as those used on actual samples. For 

sample extracts that are cleaned up using this method, the associated quality control samples 

must also be processed through this cleanup method.

9.5 The commercially available testing product used to develop this method represents 

a performance-based analytical technique. Therefore, it is imperative that the manufacturer's 
SW-846 Update V 4430 - 7 Revision 1 

October 2012 

instructions and specifications be followed closely. Follow the manufacturer's instructions for 

the testing product being used for the quality control procedures specific to that testing product. 

The following discussion of quality control requirements relies heavily on the analyst's 

knowledge and understanding of the manufacturer's instructions. 

9.6 Stringent quality assurance protocols should be maintained throughout each stage 

of the testing procedure; i.e., sample extraction, sample preparation, and immunoassay 

analysis. Various QA actions check for failure at each of these points in the process. Duplicate, 

check samples, standard reference materials, and other QA samples and methods can and 

should be used with this kit, with the exception of conventional isotope labelled internal 

standards. The AhR-PCR assay recognizes PCDD/PCDF congeners based on structure and 

not on mass. Therefore, conventional isotope-labelled internal standards are detected as native 

material and cannot be used with this method.

9.7 As outlined above, routine quality control procedures associated with this method 

include the measurement of standards, assay blanks, method blanks and recovery standards. It 

is recommended that all measurements be performed in duplicate and that all measurements be 

performed as part of the same batch of samples. A batch of samples includes up to 38 field 

samples prepared and analyzed at the same time, along with standards, assay blanks, method 

blanks and recovery standards. 

9.8 Additional quality control considerations 

9.8.1 Do not use test kit components past their expiration dates. 

 

9.8.2 Do not mix the equipment, supplies or reagents from test kits from 

different manufacturers or from different lots of the test kit. 

9.8.3 Use the test components within the storage temperature and operating 

temperature limits specified by the manufacturer. 

9.8.4 The AhR-PCR assay identifies and measures PCDD/PCDF congeners 

based on structure, not mass. Therefore isotope-labeled internal standards are 

detected as native material and cannot be used with this method.

10.0 CALIBRATION AND STANDARDIZATION 

 See the manufacturer’s instructions for information on calibration and standardization. 

11.0 PROCEDURE 

 Follow the manufacturer’s instructions for the test kit being used. Instructions can be 

found on the test kit package insert or at www.eichrom.com/dioxin/products. 

12.0 DATA ANALYSIS AND CALCULATIONS 

 Follow the instructions provided by the manufacturer for the calculation of all testing 

product results. For each batch of samples, use the calibration curve generated concurrently 

with that AhR-PCR assay run. 
SW-846 Update V 4430 - 8 Revision 1 

October 2012 

13.0 METHOD PERFORMANCE 

13.1 Performance data and related information are provided in SW-846 methods only 

as examples and guidance. The data do not represent required performance criteria for users 

of the methods. Instead, performance criteria should be developed on a project-specific basis, 

and the laboratory should establish in-house QC performance criteria for the application of this 

method. These performance data are not intended to be and must not be used as absolute QC 

acceptance criteria for purposes of laboratory accreditation. 

In the case of this method, any test kit used must be able to meet the performance 

specifications for the intended application. Also, follow the manufacturer’s instructions for 

quality control procedures specific to the test kit used. 

13.2 Table 1 depicts response on the AhR-PCR assay for 2,3,7,8-TCDD over 1 year for 

four different laboratories along with QA acceptance ranges. These data are provided for 

guidance purposes only. 

13.3 Table 2 depicts cross-reactivity on the AhR-PCR assay relative to 2,3,7,8-TCDD. 

These data are provided for guidance purposes only.

13.4 Table 3 summarizes correlation data for AhR-PCR and GC-HRMS for spiked sand 

and soil samples. These data are provided for guidance purposes only. 

13.5 Table 4 summarizes correlation data for AhR-PCR and GC-HRMS for real-world 

soil and sediment samples from US EPA Superfund Sites. These data are provided for 

guidance purposes only. 

13.6 Table 5 summarizes typical false positive and false negative rates for AhR-PCR 

near the action level of 50 pg/g TEQ. These data are provided for guidance purposes only. 

13.7 Table 6 summarizes intra-lot variation on the AhR-PCR assay. These data are 

provided for guidance purposes only. 

13.8 Table 7 summarizes inter-lot variation on the AhR-PCR assay. These data are 

provided for guidance purposes only. 

14.0 POLLUTION PREVENTION 

14.1 Pollution prevention encompasses any technique that reduces or eliminates the 

quantity and/or toxicity of waste at the point of generation. Numerous opportunities for pollution 

prevention exist in laboratory operation. The EPA has established a preferred hierarchy of 

environmental management techniques that places pollution prevention as the management 

option of first choice. Whenever feasible, laboratory personnel should use pollution prevention 

techniques to address their waste generation. When wastes cannot be feasibly reduced at the 

source, the Agency recommends recycling as the next best option. 

14.2 For information about pollution prevention that may be applicable to laboratories and 

research institutions consult Less is Better: Laboratory Chemical Management for Waste 

Reduction, a free publication available from the American Chemical Society (ACS), Committee 

on Chemical Safety, 

http://portal.acs.org/portal/fileFetch/C/WPCP_012290/pdf/WPCP_012290.pdf. 
SW-846 Update V 4430 - 9 Revision 1 

October 2012 

15.0 WASTE MANAGEMENT 

 The Environmental Protection Agency requires that laboratory waste management 

practices be conducted consistent with all applicable rules and regulations. The Agency urges 

laboratories to protect the air, water, and land by minimizing and controlling all releases from 

hoods and bench operations, complying with the letter and spirit of any sewer discharge permits 

and regulations, and by complying with all solid and hazardous waste regulations, particularly 

the hazardous waste identification rules and land disposal restrictions. For further information 

on waste management, consult the ACS publication listed in Sec. 14.2. 

16.0 REFERENCES 

1. Dioxins and Furans in Soil and Sediment, Eichrom Method DFS01, 

www.eichrom.com/dioxin/products. 

2. M. Van den Berg, L. S. Birnbaum, M. Denison, M. De Vito, W. Farland, M. Feeley, H. 

Fiedler, H. Hakansson, A. Hanberg, L. Haws, M. Rose, S. Safe, D. Schrenk, C. Tohyama, 

A. Tritscher, J. Tuomisto, M. Tysklind, N. Walker, and R. E. Peterson; “The 2005 World 

Health Organization Reevaluation of Human and Mammalian Toxicity Equivalency Factors 

for Dioxins and Dioxin-like Compounds,” Toxicol. Sci. 2006, 93[2], 223-241. 

3. R. L. Allen, J. J. Willey; “Novel Real-Time PCR Assay for the Detection of Dioxins and 

Furans,” Organohalogen Compd. 2002, 58, 341-343. 

4. D. R. McAlister, M. J. Fern, R. L.; Allen, K. Sakata, B. Le Bizec, P. Marchand; “Sample 

Preparation for the Measurement of Polychlorinated Dioxins and Furans by the Procept 

Rapid Dioxin Assay,” Organohalogen Compnd. 2006, 68, 940-943. 

5. Y. Z. Gu, J. B. Hogenesch, C. A. Bradfield; “The PAS Superfamily: Sensors of 

Environmental and Developmental Signals,” Annu. Rev. Pharmacol. Toxicol. 2000, 40, 

519-561. 

6. D. R. McAlister, M. J. Fern; “Soil Screening at 50 pg/g Using a Novel Aryl Hydrocarbon 

Receptor-based PCR Assay,” Organohalogen Compd., 2007, 69, 1230-1233. 

7. D. R. McAlister, M. J. Fern; “Cross-reactivity of Compounds on the Procept Rapid Dioxin 

Assay,” Organohalogen Compd., 2007, 69, 1226-1229. 

8. S. Heid, R. Pollenz, H. Swanson; “Role of Heat Shock Protein 90 Dissociation in Mediating 

Agonist-induced Activation of the Aryl Hydrocarbon Receptor,” Mol. Pharmacol. 2000, 

57[1], 82-92. 

9. Fed. Reg. 2006, 71, 78441, Update to ATSDR Policy Guideline for Dioxins and DioxinLike Compounds in Residential Soil. 

10. C. A. Foy, H. C. Parkes; “Emerging Homogeneous DNA-based Technologies in the 

Clinical Laboratory,” Clin. Chem. 2000, 47(6), 990-1000. 

11. D. R. McAlister, M. J. Fern, R. L. Allen; “Rapid Aryl Hydrocarbon Receptor-based 

Polymerase Chain Reaction Screening Assay for Polychlorinated Dibenzo-p-Dioxins and 

Furans in Soil and Sediment,” Talanta, 2007, in press, 

doi.org/10.1016/j.talanta.2007.08.005. 
SW-846 Update V 4430 - 10 Revision 1 

October 2012 

17.0 TABLES, DIAGRAMS, FLOWCHARTS, AND VALIDATION DATA 

 

 The following pages contain the tables referenced by this method. A glossary is provided 

after the tables. 
SW-846 Update V 4430 - 11 Revision 1 

October 2012 

Eichrom Eichrom Multi-lab Multi-lab Multi-lab Acceptable

Historical Multi-lab Site 2 Site 3 Site 4 Range

Ct range 0-5000 5.5 5.8 5.7 5.0 4.9 >4.5

R

2

 (78-5000) 0.980 0.984 0.992 0.984 0.994 >0.97

average SD of replicates 0.20 0.20 0.20 0.25 0.13 <0.30

number of curves generated 25 6 5 4 3

* Data are from 43 determinations of 2,3,7,8-TCDD Response over more than one year for 7 point standard 

curve + blank in heptane (5000, 2500, 1250, 625, 313, 156, 78 and 0 pg 2,3,7,8-TCDD/mL heptane) generated 

in four different laboratories. The assay detection limit, approximated from the lowest standard concentration, 

78 pg/mL, which lies >3σ from the assay blank, is 0.4 pg 2,3,7,8-TCDD per well. Actual achievable method

lower limits of quantitation will depend on several factors including sample size, extract volume and recoveries 

of analytes through extraction and clean-up steps.

Table 1. Standard Curve Metrics (Ct vs pg/mL 2,3,7,8-TCDD)*

These data are provided for guidance purposes only.
SW-846 Update V 4430 - 12 Revision 1 

October 2012 

AhR-PCR AhR-PCR 

Structure compound Response compound Response Structure

2,3,7,8 TCDD 1 

TEF(1) 2,3,7,8 TCDF 0.06 TEF (0.1)

1,2,3,7,8 PCDD 0.6 

TEF (1) 1,2,3,7,8 PCDF 0.1 TEF (0.03)

1,2,3,4,7,8 HxCDD 0.4 

TEF (0.1) 1,2,3,4,7,8 HxCDF 0.4 TEF (0.1)

1,2,3,6,7,8 HxCDD 0.1 

TEF (0.1) 1,2,3,6,7,8 HxCDF 0.2 TEF (0.1)

1,2,3,7,8,9 HxCDD 0.5 

TEF (0.1) 1,2,3,7,8,9 HxCDF 0.3 TEF (0.1)

1,2,3,4,6,7,8 HpCDD 0.01 

TEF (0.01) 1,2,3,4,6,7,8 HpCDF 0.05 TEF (0.01)

1,2,3,4,6,7,8,9 OCDD 0.000003 

TEF (0.0003) 1,2,3,4,6,7,8,9 OCDF 0.0005 TEF (0.0003)

2,3,4,7,8 PCDF 0.3 

TEF (0.3) 1,2,3,4,7,8,9 HpCDF 0.02 TEF (0.01)

2,3,4,6,7,8 HxCDF 0.1 

TEF (0.1)

AhR-PCR AhR-PCR 

Structure compound Response compound Response Structure

PCB-77 (3,3',4,4') 0.00003 

TEF (0.0001) PCB-126 (3,3',4,4',5) 0.01 TEF (0.1)

PCB-81 (3,4,4',5) 0.00005 

TEF (0.0003) PCB-156 (2,3,3',4,4',5) 0.00003 TEF (0.00003)

PCB-105 (2,3,3',4,4') <3 x 10-7 

TEF (0.00003) PCB-157 (2,3,3',4,4',5') 0.00004 TEF (0.00003)

PCB-114 (2,3,4,4',5) 0.00001 

TEF (0.00003) PCB-167 (2,3',4,4',5,5') 0.000001 TEF (0.00003)

PCB-118 (2,3',4,4',5) <3 x 10-7 

TEF (0.00003) PCB-169 (3,3',4,4',5,5') 0.001 TEF (0.03)

PCB-123 (2',3,4,4',5) 0.000009 

TEF (0.00003) PCB-189 (2,3,3',4,4',5,5') <3 x 10-7 TEF (0.00003)

Table 2. Cross-reactivity on the AhR-PCR Assay

Response for Chlorinated Dioxins and Furans on AhR-PCR Assay

Response for Polychlorinated Biphenyls on AhR-PCR Assay

O

O

Cl

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl

Cl Cl

O

O Cl

Cl Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl Cl

O

Cl

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Cl Cl

O

Cl

Cl

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Cl Cl

O

Cl

Cl

Cl

Cl

Cl

Cl Cl

O

Cl

Cl

Cl

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl Cl

Cl

Cl

Cl Cl

Cl Cl Cl

Cl Cl

Cl Cl

Cl

Cl Cl

Cl

Cl

Cl

Cl Cl

Cl

Cl Cl

Cl Cl

Cl

Cl Cl

Cl Cl

Cl

Cl Cl Cl

Cl Cl

Cl Cl Cl

Cl

Cl Cl

Cl Cl

Cl Cl

Cl Cl

Cl

Cl Cl

Cl

Cl Cl

Cl

Cl Cl

Cl Cl

These data are provided for guidance purposes only.
Table 2. Cross-reactivity on the AhR-PCR Assy (continued) 

SW-846 Update V 4430 - 13 Revision 1 

October 2012 

AhR-PCR analogous AhR-PCR 

Structure compound Response chloro-compound Response Structure

2,3,7,8-TBrDD 0.3 2,3,7,8-TCDD 1.0

1-Br-2,3,4,6,7,8,9-HpCDD 0.00004 1,2,3,4,6,7,8,9-OCDD 0.000003

3-Br-2,7,8-TriCDF 0.4 2,3,7,8-TCDF 0.1

2-Br-3,6,7,8,9-PCDD 0.05 1,2,3,4,7,8-HxDD 0.4

1-Br-2,3,7,8-TCDF 0.3 1,2,3,7,8-PCDF 0.1

1-Br-2,3,7,8-TCDD 0.4 1,2,3,7,8-PCDD 0.6

1-Br-2,3,6,7,8,9-HxCDD 0.06 1,2,3,4,6,7,8-HpCDD 0.01

2,3-Br-7,8-DiCDD 0.4 2,3,7,8-TCDD 1.0

2-Br-1,3,7,8-TCDD 0.6 1,2,3,7,8-PCDD 0.6

2-Br-7,8-DiCDD <10-6 2,3,7-TriCDD N/A

2-Br-3,7,8-TriCDD 0.5 2,3,7,8-TCDD 1.0

2,3,6,7-TCl-xanthene 0.7 2,3,7,8-TCDD 1.0

2,3,7,8-TCl-thiophene 0.2 2,3,7,8-TCDF 0.1

2,3,7-Cl-8-methyl-dibenzo-pdioxin 0.3 2,3,7,8-TCDD 1.0

Response for Bromo/chloro Dioxins and Furans on AhR-PCR Assay

O

O

Cl

Cl

Cl

Cl

O

O

Br

Br

Br

Br

O

O

Cl

Cl

Cl

Cl

O

O

Cl

Cl

Cl

Cl

O

O

Cl

Cl

Cl

Cl

O

O Cl

O Cl Cl

O Cl

Br Cl

O

O Cl

Cl Cl

Cl

Cl

O

O Cl

Br Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Br

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Br

O

O Cl

Cl Cl

Cl

Cl

Cl Cl

O

Cl

Cl

Cl

O Cl

Cl

Cl

Cl

Br

O

Cl

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Br

O

O

Cl

Cl

Br

Br

O

O

Cl

Cl

Br

Cl

Cl

Cl

O

O

Cl

Cl

Br

Cl

O

Cl

Cl

Cl

Cl

O

O Cl

Cl

Cl

O

O

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

S Cl

Cl

Cl

Cl

Cl

O

O Cl

Cl Cl

Cl

Br

Cl

Cl

These data are provided for guidance purposes only.
Table 2. Cross-reactivity on the AhR-PCR Assy (continued) 

SW-846 Update V 4430 - 14 Revision 1 

October 2012 

AhR-PCR AhR-PCR 

Structure Compound Response Compound Response Structure

aldrin

no measurable 

response from 

2000 ppt to 

2000 ppm

Endosulfan II

no measurable 

response from 

2000 ppt to 

2000 ppm

alpha-BHC

no measurable 

response from 

2000 ppt to 

2000 ppm

Endosulfan sulfate

no measurable 

response from 

2000 ppt to 

2000 ppm

beta-BHC

no measurable 

response from 

2000 ppt to 

2000 ppm

Endrin

no measurable 

response from 

2000 ppt to 

2000 ppm

delta-DHC

no measurable 

response from 

2000 ppt to 

2000 ppm

Endrin Aldehyde

no measurable 

response from 

2000 ppt to 

2000 ppm

p,p'-DDE

no measurable 

response from 

2000 ppt to 

2000 ppm

Endrin Ketone

no measurable 

response from 

2000 ppt to 

2000 ppm

p,p'-DDD

no measurable 

response from 

2000 ppt to 

2000 ppm

Heptachlor

no measurable 

response from 

2000 ppt to 

2000 ppm

p,p'-DDT

no measurable 

response from 

2000 ppt to 

2000 ppm

Heptachlor epoxide

no measurable 

response from 

2000 ppt to 

2000 ppm

Dieldrin

no measurable 

response from 

2000 ppt to 

2000 ppm

Methoxychlor

no measurable 

response from 

2000 ppt to 

2000 ppm

Endosulfan I

no measurable 

response from 

2000 ppt to 

2000 ppm

Response of Pesticide Compounds on AhR-PCR Assay

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl Cl

Cl

Cl Cl

Cl Cl

Cl

Cl

Cl

Cl Cl

Cl

Cl

Cl Cl

Cl Cl

Cl Cl

Cl Cl

Cl Cl

Cl Cl

Cl

O

Cl

Cl

Cl

Cl

Cl

Cl

S

O

O

O

Cl

Cl

Cl

Cl

Cl

Cl

S

O

O

O

Cl

Cl

Cl

Cl

Cl

Cl

S

O

O

O

O

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

O Cl

Cl

Cl Cl

Cl

Cl

Cl

O

H

Cl

Cl Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Cl

Cl

Cl

O

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl Cl

O O

These data are provided for guidance purposes only.
Table 2. Cross-reactivity on the AhR-PCR Assy (continued) 

SW-846 Update V 4430 - 15 Revision 1 

October 2012 

AhR-PCR AhR-PCR

structure compound Response compound Response Structure

Indeno(1,2,3-cd)pyrene 0.8 Benzo(a)pyrene 0.1

Benzo(k)fluoranthene 0.5 Benzo(a)anthracene 0.05

Benzo(b)fluoranthene 0.6 Chrysene 0.04

Dibenzo(ah)anthracene 0.3 Benzo(ghi)perylene 0.004

acenaphthylene No response at 

200 ppt to 10 ppm anthracene

No response at 

200 ppt to 

10 ppm

fluorene No response at 

200 ppt to 10 ppm naphthalene

No response at 

200 ppt to 

10 ppm

fluoranthene No response at 

200 ppt to 10 ppm phenanthrene

No response at 

200 ppt to 

10 ppm

pyrene

No response at 

200 ppt to 10 ppm acenaphthene

No response at 

200 ppt to 

10 ppm

2-methylnaphthalene No response at 

200 ppt to 10 ppm 2-chloronaphthalene

No response at 

200 ppt to 

10 ppm

biphenyl No response at 

200 ppt to 10 ppm 2,4-dichlorophenol

No response at 

200 ppt to 

10 ppm

3,4-dichlorophenol No response at 

200 ppt to 10 ppm toluene

No response at 

200 ppt to 

10 ppm

triphenylene 0.001 cyclopenta[c,d]pyrene 0.0002

2,2'-binaphthyl 0.05

Response of PAH Compounds on AhR-PCR Assay

Cl

OH

Cl

Cl

Cl OH

Cl

These data are provided for guidance purposes only.
Table 2. Cross-reactivity on the AhR-PCR Assy (continued) 

SW-846 Update V 4430 - 16 Revision 1 

October 2012 

AhR-PCR AhR-PCR

structure compound Response compound Response Structure

dibenzo-p-dioxin < 10-6 1,2,3-TriCDD 0.006

dibenzo-p-furan < 10-6 2,3,7-TriCDD 0.08

2-MCDD < 10-6 1,2,7,8-TCDD 0.9

2,3-DiCDD < 10-6 1,3,6,8-TCDD 0.001

2,7-DiCDD < 10-6 1,2,3,4-TCDD 0.007

1,7,8-TriCDD 0.004 1,2,4,7,8-PCDD 0.3

Response of non-2,3,7,8 Dioxins/Furans on AhR-PCR Assay

O

O

O

O

O

Cl

O

Cl O

Cl

O

O

Cl

Cl

O

O Cl

Cl

Cl

O

O

Cl

Cl

Cl

O

O

Cl

Cl Cl

O

O

Cl

Cl

Cl

Cl

O

O

Cl

Cl

Cl

Cl

O

O

Cl

Cl

Cl

Cl

O

O

Cl

Cl

Cl

Cl

Cl

AhR-PCR AhR-PCR

structure compound Response compound Response Structure

bis-(2-ethylhexyl)phthalate < 7 x 10-7 diethylphthalate < 7 x 10-7

di-n-butylphthalate < 7 x 10-7 dimethylphthalate < 7 x 10-7

butylbenzylphthalate < 7 x 10-7 di-n-octylphthalate < 7 x 10-7

C10H22 decane < 9 x10-7 eicosane < 9 x10-7 C20H42

C12H26 dodecane < 9 x10-7 docosane < 9 x10-7 C22H246

C14H30 tetradecane < 9 x10-7 tetracosane < 9 x10-7 C24H50

C16H34 hexadecane < 9 x10-7 hexacosane < 9 x10-7 C26H54

C18H38 octadecane < 9 x10-7 octacosane < 9 x10-7 C28H58

octamethylcyclotetrasiloxane

no measurable 

response from 

2000 ppt to 

2000 ppm

benzophenone < 1 x10-6

Response of Miscellaneous Compounds on AhR-PCR Assay

O

Si

Si O

Si

O

O Si

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

O

These data are provided for guidance purposes only.
SW-846 Update V 4430 - 17 Revision 1 

October 2012 

GC-MS AhR-PCR 50pg/g GC-MS AhR-PCR 50pg/g

TEQ TEQ screen TEQ TEQ screen

0.03 0.6 CN 0.03 0.4 CN

0.03 0.4 CN 0.03 0.3 CN

0.03 0.8 CN 0.03 0.5 CN

0.03 0.4 CN 0.03 0.5 CN

0.03 0.6 CN 0.03 0.4 CN

0.03 0.6 CN 0.03 0.3 CN

5 6.9 CN 5 4.8 CN

5 5.9 CN 5 3.6 CN

5 4.6 CN 5 6.0 CN

5 4.9 CN 5 3.7 CN

5 4.7 CN 5 3.3 CN

5 4.5 CN 5 3.1 CN

25 22 CN 25 30 CN

25 29 CN 25 22 CN

25 29 CN 25 26 CN

25 28 CN 25 21 CN

25 35 CN 25 32 CN

25 22 CN 25 28 CN

50 45 FN 50 54 CP

50 50 CP 50 48 FN

50 52 CP 50 66 CP

50 31 FN 50 39 FN

50 62 CP 50 37 FN

50 76 CP 50 29 FN

75 80 CP 75 74 CP

75 90 CP 75 59 CP

75 103 CP 75 54 CP

75 82 CP 75 75 CP

75 83 CP 75 84 CP

75 52 CP 75 65 CP

500 610 CP 500 534 CP

500 652 CP 500 305 CP

500 627 CP 500 409 CP

500 372 CP 500 467 CP

500 646 CP 500 483 CP

500 497 CP 500 306 CP

1000 1275 CP 1000 939 CP

1000 1006 CP 1000 898 CP

1000 1078 CP 1000 771 CP

1000 710 CP 1000 1007 CP

1000 720 CP 1000 937 CP

1000 1040 CP 1000 930 CP

1500 1126 CP 1500 1214 CP

1500 1224 CP 1500 1187 CP

1500 1570 CP 1500 1168 CP

1500 876 CP 1500 961 CP

1500 1584 CP 1500 1234 CP

1500 1538 CP 1500 1293 CP

CP = Correct Positive, CN = Correct Negative, FP = False Positive, FN = False Negative

Table 3. Correlation of AhR-PCR with GC-HRMS for Spiked sand and loamy soil

sand loamy soil
SW-846 Update V 4430 - 18 Revision 1 

October 2012 

GC-HRMS AhR-PCR 50pg/g GC-HRMS AhR-PCR 50pg/g GC-HRMS AhR-PCR 50pg/g

TEQ (pg/g) TEQ (pg/g) screen TEQ (pg/g) TEQ (pg/g) screen TEQ (pg/g) TEQ (pg/g) screen

0.03 0.6 CN 0.03 2.1 CN 0.03 0.7 CN

14 14 CN 16 22 CN 0.03 1 CN

14 11 CN 16 18 CN 0.03 1 CN

14 6.8 CN 16 17 CN 0.03 1 CN

14 14 CN 16 19 CN 42 62 FP

12 8.8 CN 32 32 CN 42 21 CN

12 3.9 CN 32 37 CN 42 26 CN

12 11 CN 32 35 CN 42 21 CN

12 10 CN 32 25 CN 435 435 CP

15 15 CN 38 29 CN 435 637 CP

15 10 CN 38 36 CN 435 406 CP

15 10 CN 38 43 CN 435 255 CP

15 10 CN 38 26 CN 808 597 CP

14 15 CN 45 53 FP 808 2383 CP

14 8.4 CN 45 40 CN 808 423 CP

14 15 CN 45 44 CN 808 1276 CP

14 9.3 CN 45 36 CN 1048 1246 CP

13 14 CN 62 61 CP 1048 1136 CP

13 10 CN 62 55 CP 1048 1237 CP

13 10 CN 62 45 FN 1048 877 CP

13 10 CN 62 37 FN 3127 1548 CP

3127 995 CP

3127 5578 CP

3127 3083 CP

GC-HRMS AhR-PCR 50pg/g GC-HRMS AhR-PCR 50pg/g

TEQ (pg/g) TEQ (pg/g) screen TEQ (pg/g) TEQ (pg/g) screen

0.03 6.2 CN 0.03 5.2 CN

48 359 FP 8648 16393 CP

48 465 FP 8648 6684 CP

48 479 FP 8648 9972 CP

48 371 FP 8648 12430 CP

846 721 CP 8831 9889 CP

846 667 CP 8831 10716 CP

846 541 CP 8831 9183 CP

846 466 CP 8831 19528 CP

1279 859 CP 11071 11018 CP

1279 1201 CP 11071 17503 CP

1279 599 CP 11071 20696 CP

1279 1123 CP 11071 28013 CP

1833 1833 CP 11259 33839 CP

1833 1938 CP 11259 8139 CP

1833 1516 CP 11259 7410 CP

1833 1243 CP 11259 26151 CP

3257 4541 CP 11410 15053 CP

3257 3083 CP 11410 15297 CP

3257 2944 CP 11410 7100 CP

3257 2692 CP 11410 12760 CP

3951 4631 CP

3951 3935 CP

3951 3214 CP

3951 3352 CP

Solutia Soils Winona Post Soils

Table 4. Correlation of GC-HRMS and AhR-PCR Assay for Real World Soils

Raritan Bay Sediment Newark Bay Sediment Tittabawasse River Soil 
SW-846 Update V 4430 - 19 Revision 1 

October 2012 

GC-MS Procept Screen at 50 pg/g GC-MS Procept Screen at 50 pg/g

TEQ (pg/g) TEQ (pg/g) Result TEQ (pg/g) TEQ (pg/g) Result

25 22 True Negative 25 30 True Negative

25 29 True Negative 25 22 True Negative

25 29 True Negative 25 26 True Negative

25 28 True Negative 25 21 True Negative

25 35 True Negative 25 32 True Negative

25 22 True Negative 25 28 True Negative

75 80 True Positive 75 74 True Positive

75 90 True Positive 75 59 True Positive

75 103 True Positive 75 54 True Positive

75 82 True Positive 75 75 True Positive

75 83 True Positive 75 84 True Positive

75 52 True Positive 75 65 True Positive

Table 5. Example False Positive and Negative Rates Near Action Level (50pg/g)

Spiked Sand Spiked Soil
SW-846 Update V 4430 - 20 Revision 1 

October 2012 

Spiked Sample1 Mean Procept Standard

(pg/g TEQ) Response (ppt)2 Deviation2 % RSD2,3 % Recovery4

Blank 0.8 0.1 17 N/A

5.0 6.3 0.7 12 126

25 26 5.0 20 104

50 46 10 22 91

75 70 15 21 93

500 720 130 18 143

1000 1400 260 19 138

1500 1900 460 24 127

1Sand matrix spiked with 7 Dibenzo-p -Dioxin/Furan Standards (tetra-hexachloro)

2Eight measurements at each concentration on single lot of test kit on same day

3Relative standard deviation (standard deviation*100%/mean value)

4

(Mean AhR-PCR Response)*100%/Spike Concentration (pg/g TEQ)

Table 6. Same lot variation of Measurement
SW-846 Update V 4430 - 21 Revision 1 

October 2012 

Spiked Sample1 mean mean mean Inter-lot Mean AhR-PCR Inter-lot

(pg/g TEQ) lot 1018062

lot 011062lot 0330062 Response (pg/g TEQ) % RSD3

Blank 0.8 0.3 0.4 0.5 61

5.0 6.3 8.4 8.2 7.6 15

25 26 32 36 31 16

50 46 51 43 46 9

75 70 62 83 72 15

500 720 560 620 630 13

1000 1400 1200 1400 1300 9

1500 1900 1400 1500 1600 17

1

Sand matrix spiked with 7 Dibenzo-p -Dioxin/Furan Standards (tetra-hexachloro)

2Mean of Four to Eight measurements on each lot

3Relative standard deviation (standard deviation*100%/mean value)

Table 7. Variation of Measurement Between 3 Lots
SW-846 Update V 4430 - 22 Revision 1 

October 2012 

GLOSSARY 

2,3,7,8-TCDD - 2,3,7,8-tetrachlorodibenzo-p-dioxin 

AhR (aryl hydrocarbon receptor) -- A chemical-responsive DNA-binding protein that is 

responsible for producing the toxic and biological effects of dioxin and related chemicals 

ARNT - Aryl hydrocarbon receptor nuclear translocator protein 

Congener - Compounds containing different numbers and position of chlorine atoms (or other 

substituent) on the same base structure. 

Ct (threshold cycle) - This is the output of the real-time PCR instrument. Threshold cycle 

corresponds to the number of PCR temperature cycles at which the measured fluorescence of a 

sample well exceeds a threshold value. The threshold value is set by the user, or software, to 

optimize the linearity of the standard curve. Comparing the Ct of an unknown sample to an 

appropriate standard curve allows the analyst to relate Ct to concentration or TEQ. 

DRE - DNA response element 

PAHs - Polycyclic aromatic hydrocarbons 

PCBs - Polychlorinated biphenyls 

PCDD/PCDFs - Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. 

PCR (polymerase chain reaction) - A technique employed to replicate and measure the 

concentration of DNA fragments. 

TEF (toxicity equivalent factor) - Toxicity values established by the World Health Organization 

(WHO) for chlorinated dibenzo-p-dioxins and furans and polychlorinated biphenyls relative to 

2,3,7,8-tetrachlorodibenzo-p-dioxin. 

TEQ (toxicity equivalent quotient) - The sum of the concentration of dioxin congeners multiplied 

by their TEF value. TEQ = ∑(congener concentration) x (TEF). 
SW-846 Update V 4430 - 23 Revision 1 

October 2012 

Appendix A:

Summary of Revisions to Method 4430 (as compared to previous Revision 0, December 2007)

1. Improved overall method formatting for consistency with new SW-846 methods style 

guidance. The format was updated to Microsoft Word 2007.docx. 

2. Minor editorial and technical revisions were made throughout to improve method clarity. 

3. The revision number was changed to 1 and the date published was changed to May 

2012. 

4. This appendix was added showing changes from the previous revision. 

5. Sec. 9.2.1 was added to discuss the need for initial demonstration of proficiency (IDP).