LIMIT OF DETECTION: Color Card: 100 ppb (as aroclor 1254), DTECHTOR meter: 50 ppb (as aroclor 1254)
This application describes a field screening method for determining PCB concentrations in water. A 1:2 dilution of the sample in methanol is made to minimize adsorptive losses. A chemical reaction is induced that causes a color change indicative of PCB in the sample. The PCB concentration is estimated by comparison of the color development to a color card or reading of the relative reflectance with the DTECHTOR meter.
Extraction and analysis should be performed in a well ventilated area. Laboratory technicians should wear chemical resistant gloves and safety glasses. Use gloves during the entire procedure..
The major drawback in testing water samples for the presence of PCB is the fact that PCBs have a very low solubility in water. The solubility of PCB in water generally decreases as the chlorination increases. Solubility ranges listed below were obtained from a textbook reference:
Biphenyl (0% Chlorination) 7.2 ppm
Aroclor 1254 (54% Chlorination) 10-31 ppb
Aroclor 1260 (60% Chlorination) <1 ppb
Aroclor 1240 (40% Chlorination) 40-170 ppb
Aroclor 1230 (30% Chlorination) 85-92 ppb
Aroclor 1221 (21% Chlorination) 500-1500 ppb
Comparing our water sample analysis limit with the solubility information provided above, the usefulness for the DTECH PCB test kit for water samples is obviously limited. Lower chlorination generally increases the solubility and therefore also increases the potential application of the DTECH test kit. However, it must be noted that our minimum detection level for these less chlorinated PCBs in many cases may also be higher.
MATERIALS: DTECH PCB Test Kit, Methanol (ACS Reagent Grade)
Equipment: DTECHTOR meter (optional)
1. Follow the procedure in the DTECH PCB Soil Test Kit Instruction Guide to analyze samples.
2. In Step 1, instead of adding 0.5 mL of solution to Bottle A, add 4.5 mL of water sample directly to Bottle A. Snap the filter tips and gently mix by inverting three (3) times.
3. Continue with procedure at Step 2.
Calculate the concentration in the water sample by using the color card supplied with the kit or the DTECHTOR and the table in the Interpretation” section of the test kit instuction guide. To determine the wipe concentration in the wipe sample, the soil equivalents should be divided by 10.
The DTECH PCB test kits will also react to other PCB aroclors. Please refer to the Specificity chart in the test kit instruction guide for detailed reactivities. Do not use reagents or components from one test kit with reagents or components from another. Do not use the test kits beyond the expiration date. Store at less than 80°F and run procedure out of direct sunlight.
EXPECTED RESULTS: See U.S. EPA SW-846 Method 4020 for PCB analysis in soil.