Evaluation and Comparison of Three Common Methods for PFAS Extraction from Soybean Tissues

This study evaluated three methods, methyl <i>tert</i>-butyl ether-sodium hydroxide (MTBE-NaOH) method, EPA method 1633, and U.S. Food and Drug Administration (FDA) chemical analytical manual (CAM) method C-010.03, for their effectiveness in extracting PFAS from soybean tissues. EPA method 1633 consistently delivered the highest and most reproducible EIS recoveries when plant tissues contained PFAS at low levels. Regarding target PFAS extraction efficiency, EPA method 1633 also demonstrated superior performance at environmentally relevant low concentrations. At higher PFAS concentrations in plant tissues, no single method clearly dominated; however, EPA method 1633 remained consistently reliable and was never significantly outperformed by the other two methods. Overall, EPA method 1633 is recommended as the default method for routine analyses at typical environmental PFAS levels, with MTBE-NaOH method preferred when accurate isotopic correction based on EIS recovery is critical in highly contaminated plant samples. A cost comparison of these three methods further supports the preference for EPA Method 1633 and MTBE-NaOH method for plant-tissue analyses. These findings contribute to PFAS risk assessment in agricultural and food safety contexts by enhancing the understanding of PFAS interactions with edible crops.