Development, optimization and validation of a highly sensitive and selective method for the determination of PFAS in animal-based food.

Perfluorocarboxylic acids and perfluorosulfonic acids accumulate in food webs, thus posing a serious threat to food safety. The European Food Safety Authority (EFSA) derived a tolerable weekly intake (TWI) of 4.4 ng/kg body weight for the sum of the four so-called EFSA-PFAS in 2020. More sensitive analytical methods are urgently needed, not only to monitor maximum levels, but also for future toxicological assessments of these substances. Therefore, in the present study a dual SPE approach for the purification of the extracts was chosen to attain high and valid sensitivity for the matrices egg, liver, milk and dairy products using liquid chromatography coupled with tandem mass spectrometry. This method achieved limits of quantification of 2.60 (PFOS) - 6.80 ng/kg (PFHxS) for egg, 9.80 (PFOS) - 46.0 ng/kg (PFHxS) for liver and 0.165 (PFNA) - 0.455 ng/kg (PFOS) for milk for the 4 EFSA-PFAS. Summed medians for the 4 EFSA-PFAS of 396 ng/kg in bovine liver and 54.0 ng/kg in pork liver, as well as 8.46 ng/kg in cheese and 4.57 ng/kg in milk were detected. The results were subjected to correlation analysis. Statistically significant strong correlations were identified between bovine and porcine liver for PFNA, PFDA, PFUnDA and PFOS. To summarize the PFAS content and the PFAS spectrum detected depend on the animal species examined. Furthermore, an estimation of the exhaustion of the TWI for children, women and men was conducted. In our model, a TWI exhaustion of more than 27.0% (children) was calculated for liver, milk and cheese.