Comparative evaluation of three extraction techniques: Validation of a novel approach for the determination of 51 Per- and Polyfluoroalkyl substances in Graminaceous plants

Per- and polyfluoroalkyl substances (PFAS) are a class of over 15,000 xenobiotic compounds that have permeated across the globe and are largely resistant to natural forms of degradation, resulting in their long-term environmental persistence. These compounds can bioaccumulate and cause toxicological effects in organisms living within PFAS contaminated ecosystems. Grasses and feedstocks grown on contaminated farmlands are intermediates in the transmission of PFAS from contaminated soil to livestock and humans and may provide a potential avenue for biomonitoring of PFAS as they permeate through agricultural food systems. However, extraction methods for these compounds in graminaceous plants are sparse, non-standardized and limited in analytical range of PFAS compounds. This study outlines the development of a novel method of extraction using an alkaline, methanol-based solid-liquid extraction technique for 51 PFAS in graminaceous plant material, including nine separate PFAS subclasses. In comparison to two other previously published methods, this alkaline, methanolic solid-liquid approach has statistically significantly improved analyte recoveries for 22 of the 51 tested PFAS, ranging from 64.7–139% recovery in previously unexposed prairie grass (Panicum virgatum and Dactylis glomerata). Method detection limits range from 0.091 – 53.7 parts per trillion across tested PFAS analytes, demonstrating increased precision and sensitivity when compared to two other tested extraction procedures. This method’s strategy of alkaline, methanolic SLE may serve as a foundation for further testing across new plant taxa and an increased range of PFAS analytes.