Development of a U.S. EPA method for the analysis of select pesticides and fungicides in drinking water by solid phase extraction and LC/MS/MS
Citation:
Tettenhorst, D. AND J. Jones. Development of a U.S. EPA method for the analysis of select pesticides and fungicides in drinking water by solid phase extraction and LC/MS/MS. American Chemical Society National Conference, San Francisco, CA, August 13 - 17, 2023.
Impact/Purpose:
This research will produce a drinking water method that may be used to collect nationwide occurrence data for contaminants in drinking water. This occurrence data could be used to inform decisions on protecting human health.
Description:
The U.S. Environmental Protection Agency’s (EPA) Office of Groundwater and Drinking Water (OGWDW) through the Office of Water (OW) is responsible for protecting the nation’s drinking water from known and emerging contaminants. Historically, OGWDW has used the Drinking Water Contaminant Candidate List (CCL) of microbes and chemicals to identify chemicals that might require future regulation for the protection of drinking water. The CCL is a list of contaminants that are not currently subject to any proposed promulgated national primary drinking water regulations. The CCL contaminants are known or anticipated to occur in public water systems. One of the key pieces of information that must be available in order to make a regulatory determination is nationwide occurrence data for the contaminants under consideration. Historically, OGWDW has collected the necessary occurrence data under its Unregulated Contaminant Monitoring Rule (UCMR). Thus, standardized methods that will produce data of sufficient quality for UCMR monitoring of contaminants on CCL 5 are needed. CCL 5, published in November of 2022, has identified seven pesticides or fungicides and two degradates as contaminants of interest to OW. A rugged solid phase extraction (SPE)-LC/MS/MS method is being developed for these chemicals that adequately addresses issues specific to analyzing compounds in drinking water, such as preservatives, internal and surrogate standards, and aqueous sample and extract holding times. Samples were preserved with sodium bisulfate to inhibit microbial growth and ascorbic acid for dechlorination. Preliminary recoveries of 86.8 – 97.4% with RSDs of <8.4% in 500 mL of preserved deionized water have been obtained using polymeric highly cross linked divinylbenzene SPE cartridges. Precision and accuracy data in surface water and ground water will be presented.