For detection of Polychlorinated Biphenyls (PCB’s) (as Aroclor 1254) in soil. For testing in other matrices, please contact our technical support department at 1-800-544-8881.
Materials Required but Not Provided
SDI Sample Extraction Kit
(Part Number: A00137EA/A00137EB)
Procedural Notes and Precautions
- Prepare soil samples for analysis according to the procedure in the SDI Sample Extraction Kit Users Guide.
- After extraction and dilution of samples, follow the immunoassay procedure as described in the Rapid Assay PCB Test Kit User’s Guide.
- The initial 2x dilution described for water samples in Step 1 of “Collect/Store the Sample” does not need to be performed for soil samples.
A control solution at approximately 3 ppb (as Aroclor 1254) is provided with the PCB RaPID Assay Kit. It is recommended that it be included in every run and treated in the same manner as unknown samples. If running standard soil procedures an acceptable result should be 2000 times the value stated on the control vial (i.e. 6.0 + or – 1.2 ppm) when the control results are corrected for the dilution factors (see Results section below).
Interpret soil sample results as described in the RaPID Assay PCB Test Kit procedure, accounting for the total dilution factor indicated in the table of the SDI Sample Extraction Kit Users Guide. Alternatively, program the RPA-1 Analyzer as listed below to automatically correct for this dilution factor.
1. The RPA-I photometer (provided in the Rapid Assay Accessory kit) can be used to calculate and store calibration curves. To obtain soil results from the PCB Rapid Assay test kit on the RPA-I the following parameter settings are recommended:
Data Reduct : Lin. Regression
Xformation : Ln/LogitB
Read Mode : Absorbance
Wavelength : 450 nm
Units : PPM
# Rgt Blk : 0
# of Cals : 4
# of Reps : 2
#1: 0.00 PPM
#2: 0.50 PPM
#3: 2.00 PPM
#4: 10.00 PPM
Range: 0.5 – 10.00
Rep. %CV: 10%
The PCB RaPID Assay does not differentiate between PCB and other related compounds. The table below shows compounds at the method detection limit (MDL) which is the lowest concentration of the compound in soil that can be picked up in the assay. The limit of quantitation (LOQ) is an approximate concentration required to yield a positive result at the lowest standard, this is the lowest concentration of the compound in soil that can be quantified in the assay. The IC50 is the concentration in soil required to inhibit one half of the color produced by the negative control. It is also used to calculate cross-reactivity values to similar compounds.
Some contaminants found in soils that also contain PCB’s can interfere with the analysis and cause false positives, false negatives or both when the compound is present at elevated concentrations. Interferences were assessed by adding increasing concentrations of some relevant contaminants to blank and PCB spiked soils prior to the extraction procedure. The concentration of the compound shown below produced no evidence of interference in a positive or negative direction in the 500 ppb to 10 ppm detection range of the procedure described above.
If additional dilutions of the soil extract are made to detect soil PCB concentrations greater than 10 ppm, these interferences are diminished in direct proportions to the dilution made.
Range of Detection
The PCB RaPID Assay has a range of detection in soil of 500 ppb to 10 ppm (as Aroclor 1254) when used in conjunction with the SDI Sample Extraction Kit.
PCB recoveries will vary depending on soil type, retention mechanism, solvent and extraction apparatus used, length of extraction period and levels of potentially interfering substances in the soil.