RANGE OF EVALUATION: 0.5 to 4.0 ppb
Atrazine RaPID Assay Kit and Sample Diluent (cat. no. A00051)
Reagents: U.S. EPA Reference Standard for atrazine with certified concentration of 1000 μg/mL, in methanol ( NSI Environmental Solutions, Research Triangle Park, NC).
Equipment: precision micropipets: 100 μL and 500 μL (Rainin, Woburn, MA), 50 mL and 100 mL volumetric flasks, 10 mL glass test tubes with stoppers or 10 mL glass scintillation vials with screw caps, 5 and 10 mL serological pipets.
Add approximately 90 mL of the Sample Diluent to a 100 mL volumetric flask. Add 100 μL of the EPA standard material to the volumetric flask. Add Sample Diluent quantity sufficient to 100 mL and invert several times to mix. Label this flask as 'Stock I: 1000 ppb'. Prepare a second stock solution by adding approximately 40 mL of the Sample Diluent to a 50 mL volumetric flask. Add 500 μL of 'Stock I' to the volumetric flask. Add Sample Diluent quantity sufficient to 50 mL and invert several times to mix. Label this flask as 'Stock II: 10 ppb'. Prepare the solutions to be tested in the immunoassay by diluting various volumes of the 'Stock II' solution to 10 mL with Sample Diluent. See the table below for dilution scheme. First, add the diluent with a 10 mL serological pipet to the 10 mL tube or vial. Then use the 5 mL serological pipet to deliver the Stock II solution to the container. Mix the solutions by inverting several times.
ANALYSIS: Analyze a 200 μL portion of each of the test solutions as the 'sample' according to the package insert for the Atrazine RaPID Assay.
PROCEDURAL NOTES: Test solutions may be prepared in 10 mL volumetric flasks to achieve greater accuracy in making dilutions.
EXPECTED RESULTS: Recovery of 80 to 120% of the calculated test solution atrazine concentration expected when this procedure is used.