Serum samples were analyzed for PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUdA, PFDoA, PFBS, PFHxS, and PFOS. About 250 μL of serum were spiked with labelled internal standards. Extraction was performed with acetonitrile, reduced and transferred to an autosampler vial to undergo instrumental analysis.