Per- and Polyfluoroalkyl Substances (PFAS) in Food Products by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS), AOAC Official Method 2025.07, First Action

BACKGROUND: Poly- and perfluoroalkyl substances (PFAS) are fluorinated organic chemicals, which include perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). PFAS are persistent and bioaccumulate. PFAS can enter the food supply through plants and animals grown, raised, or processed in contaminated areas. OBJECTIVE: This single-laboratory validation (SLV) study was conducted for a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to determine 30 PFAS in a variety of foods, including produce, coffee, milk, protein powders, eggs, seafood, fish meat, edible offal, fish oil, baby food, and pet food, and to compare with AOAC INTERNATIONAL Standard Method Performance Requirement (SMPR(®)) 2023.003. METHOD: Matrixes were extracted using acetonitrile and QuEChERS reagents and then purified by solid-phase extraction (SPE) and concentrated under nitrogen. Fish meat did not require concentration under nitrogen, and fish oil and edible offal did not require QuEChERS reagents and sample concentration to reach the required limit of quantitation (LOQ). RESULTS: The LC-MS/MS system provides linear responses in the range of 0.01–25 μg/kg for most target analytes, depending on the matrix. Triplicate determinations over at least three spiking concentrations were made in each matrix with quantitation by isotopic dilution. We evaluated recovery, precision, retention time, blanks, ion ratios, and signal-to-noise ratio of the qualifier ions in all matrixes to determine the LOQ. Potential interference from cholic acids were separated chromatographically. CONCLUSIONS: The method developed and validated for the analysis of PFAS in food met the LOQ and recovery and precision requirements of the SMPR. HIGHLIGHTS: The LC-MS/MS method developed uses a single set of operating conditions, enabling easy and rapid transfer of the method. The extraction is simplified, with only small variations necessary due to the sample matrix. The implementation of this method is cost-effective to laboratories due to minimal solvent usage and labor required to extract samples.