Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Evaluation of C18 Solid-Phase Extraction Cartridges for the Isolation of Select Pesticides and Metabolites

Authors
item Novak, Jeffrey
item Watts, Donald

Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 5, 1997
Publication Date: N/A

Interpretive Summary: Pesticides are used by farmers and landowners to control weeds, insects, and plant diseases. Since pesticides are sometimes detected in drinking water supplies, methods for pesticide detection are continually being developed and evaluated. A method is available where pesticides in the water sample are extracted using a cartridge containing a resin that holds the pesticide while the water is removed. The pesticide is then rinsed fro the resin with a solvent and measured using analytical instruments. Several different types of resin cartridges are commercially available; however, a thorough evaluation of their extraction efficiency has not been conducted. We evaluated nine cartridges for their ability to extract 11 pesticides dissolved in water. We found that only four of the cartridges gave acceptable results, while the other six gave marginal to poor recoveries. These results are important for scientists monitoring for the presence of certain pesticides in water because some cartridges will bind their target pesticide better than others. Proper selection of a cartridge is important when determining for the presence of pesticides in drinking water supplies.

Technical Abstract: Isolation of pesticides and metabolites from water matrices typically requires an extraction and/or concentration procedure. Solid-phase extraction (SPE) has become a convenient method for pesticide isolation from water matrices when compared to classical liquid-liquid extraction procedures. Numerous types of C18 SPE cartridges are commercially available; however, an evaluation of their pesticide and metabolite extraction efficiency has not been thoroughly conducted. Nine different C18 SPE cartridges were evaluated for their efficiency at extracting nine pesticides and two metabolites from spiked deionized water samples. Cartridge type had a substantial effect on the recovery of certain pesticides and metabolites. Four of the nine SPE cartridges gave acceptable (70 to 110%) recovery percentages, while five cartridges had marginal (50 to 70%) to poor recoveries (<50%). Extracts from unspiked samples were found to contain nitrogen and/or phosphorus containing contaminants, some of which coeluted with our peaks of interests. These results indicate that several cartridges should be evaluated in order to optimize certain pesticide and metabolite isolation from water matrices.

Last Modified: 11/27/2014