EPA has released a newly developed and validated analytical methodology for testing pesticide products for the presence of per- and polyfluoroalkyl substances (PFAS). Referred to as the ACB Method, this new PFAS-detection method was developed by EPA’s Analytical Chemistry Branch (ACB). The ACB Method primarily differs from an alternative PFAS-detection method (the Lasee Method) in its approach to sample preparation. As background, the Lasee Method was introduced by Steven Lasee in November 2022 in his co-authored study titled “Targeted Analysis and Total Oxidizable Precursor assay of several insecticides for PFAS” in the Journal of Hazardous Materials.

The Lasee Method prepares a sample through dilution in a solvent/water solution to dilute the matrix using a single instrument for analysis. The ACB Method requires a more intense extraction to isolate PFAS compounds from the sample matrix before instrumental analysis, thereby reducing matrix interference and increasing the accuracy of PFAS detection. In short, EPA’s ACB Method is designed to eliminate interference from non-volatile oils and surfactants present in pesticide formulations that can result in false positive detections of PFAS. EPA’s verification analysis contains additional scientific details on the difference between the two methods and the significance of using EPA’s ACB Method when testing specific formulations.