ARS | Publication request: EVALUATION OF AN ELISA KIT FOR THE DETECTION OF METRIBUZIN IN STREAM WATER

Submitted to: Journal of Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 10, 1996
Publication Date: N/A

Interpretive Summary: Detecting pesticides in stream water is an important step toward protecting the health of our environment; however, doing it can require a lot of time and equipment that costs thousands of dollars. A recently developed method, enzyme-linked immunosorbent assays (ELISA), used to detect pesticides in water is cheaper and quicker than many of the previously used methods. Before this new method can confidently be used, it needs to be tested against previously proven methods. This paper reports on the testing of an ELISA for the detection of a commonly used herbicide. Repeated measurement of stream water containing this herbicide showed that the ELISA would generally give a similar value over several days of testing. When the ELISA was compared to one of the previously proven methods, it was found that the ELISA was very comparable to this older method. Overall, the assay illustrated the ability to efficiently and accurately predict concentrations of this herbicide in stream water.

Technical Abstract: Classical pesticide extraction and quantification in environmental samples are often time consuming and require expensive analytical instruments. Enzyme-linked immunosorbent assays (ELISA) have recently been shown to be a rapid and inexpensive screening tool for pesticide detections. A recently developed magnetic-based ELISA for the herbicide metribuzin [4-amino-6-1(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] wa evaluated for its reproducibility, accuracy, and comparability to results from a gas chromatography/mass spectrometry (GC/MS) technique. Replicated metribuzin determination in stream water showed good daily reproducibility (CV <10%) except at low concentrations (<0.69 ug/L). The assay correlated well (r=0.954) with GC/MS results. Predicted accuracy by the metribuzin assay was tested in two matrices (stream and deionized water). Deionized water exhibited excellent agreement between the theoretical and predicted metribuzin levels indicating a high degree of accuracy. Predicted metribuzin concentrations were slightly elevated compared to theoretical concentrations in stream samples; however, no significant difference (p <0.05) was found between the two sample matrices. Overall, the assay illustrated the ability to efficiently and accurately predict concentrations of metribuzin and demonstrated the utility of the ELISA technique as a screening tool for the determination of metribuzin in stream samples.