The Analysis of PFAS in Milk by LC‐MS/MS

Per-and polyfluoroalkyl substances (PFAS) are a class of manufactured organic compounds that are used for a wide array of applications and products.The environmental prevalence and bioaccumulation of these compounds can lead to contamination of produce and other commodities meant for human consumption.One potential complication of this analysis is the presence of co-extractables, such as bile acids, found in the final sample.Bile acids, taurochenodeoxycholic acid (TCDCA), tauroursodeoxycholic acid (TUDCA), and taurodeoxycholic acid (TDCA), are endogenous compounds that are formed in the liver.These compounds share the same mass transition with some of the target PFAS in this method and can be detected at high concentrations in samples of animal origin.In this application, a workflow was developed for the analysis of 28 PFAS compounds in milk, resolving the target PFAS from potential bile acid interferences.To prepare samples, a QuEChERS approach coupled with dSPE was implemented.This workflow returned exceptional results for the four PFAS compounds required in the Guidance Document on Analytical Parameters for the Determination of Per-and Polyfluoroalkyl Substances (PFAS) in Food and Feed released by the European Union Reference Laboratory for Halogenated POPs in Feed and Food.Recoveries for the four main PFAS compounds ranged from 100.7 -113.0%and %RSD of 2.56 -16.6% with acceptable method accuracy and precision results achieved for the majority of other compounds also monitored.While detectable levels of bile acid interferences were not observed in tested milk samples, the chromatographic method developed herein is suitable to apply to other matrix samples of animal origin for the detection of PFAS compounds where high levels of bile acids may be present.