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A SIMPLE ASSAY FOR 2,4-DICHLOROPHENOXYACETIC ACID USING COATED TEST-STRIPS
Citation:
Weetal, H. H. AND K R. Rogers. A SIMPLE ASSAY FOR 2,4-DICHLOROPHENOXYACETIC ACID USING COATED TEST-STRIPS. ANALYTICAL LETTERS 35(8):1341-1348, (2002).
Impact/Purpose:
The overall objective of this task is to develop scientifically sound sampling and bioanalytical approaches for screening and monitoring of hazardous wastes. These techniques are expected to provide the Agency with improved screening and field portable methods to characterize, reduce, and control risk to human health and the environment. Specific objectives will include development and characterization of the following concepts:
SPMDs for passive accumulation of TICs
Bioassays for toxic and genotoxic compounds
MIPs for volatile and semivolatile toxic organics
Rapid screening assays using the previously listed components.
Description:
Immunoassay test strips utilizing ascending chromatography has been devised for the detection of 2.4-dichlorophenoxyacetic acid (2,4-D). This test requires no instrumentation, inexpensive reagents and relies on the application of antibodies to 2,4-D adsorbed onto colloidal gold particles. The assay, although not completely optimized is capable of detecting 0.10ug/mL. The format for this assay involves addition of the unknown sample to a small test tube that contains 0.5 mL buffer and anti-2,4-D colloidal gold conjugate followed by addition of the test strip. For this assay, the anti-2,4-D gold conjugate co-migrates with the sample past pre-adsorbed bovine albumin labeled with 2,4-D (BSA-2,4-D). If 2,4-D is in the unknown sample at concentrations above the threshold value, then the colloidal gold-labeled anti-2,4-D antibody will not bind to the BSA-2,4-D adsorbed to the nitrocellulose strip but continue to migrate toward the top of the strip. To determine the presence of the analyte, the colloidal gold labeled antibody that binds to the BSA-2,4-D zone (as determined by a visible purpose band) is compared to positive (containing concentrations of 2,4-D above 0.02 ug/ml) and negative controls (containing no analyte).
The U.S. Environmental Protction Agency (EPA), through its Office of Research and Development (ORD), has funded and performed the research described. This manuscript has been subjected to the EPA's peer and administrative review and has been approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation by the US EPA.