The per- and polyfluoroalkyl substances (PFAS) targeted for analysis in blood may vary based on the specific concern in a given region or population. Some commonly analyzed PFAS range from short- to long-chain compounds (C4 – C10). The ultrashort-chain (USC) PFAS with carbon chain lengths of shorter than C4 have become a major concern due to their prevalence and high levels of occurrence in environmental aquatic systems. Several studies have indicated a rapid increase in environmental concentration of USC PFAS, raising the concern of elevated human exposure. The measurement of USC PFAS in blood can not only monitor the human exposure but also provide a tool for studying the potential risks associated with USC PFAS exposure.
Accuracy and precision test was conducted using fetal bovine serum fortified with C1 to C10 carboxylic acid and sulfonic acid PFAS. A 100 μL aliquot of serum sample was mixed with both extracted and nonextracted internal standards, along with 200 μL of methanol containing 1.5% formic acid. After centrifugation, 5 μL of supernatant was injected onto a polar-embedded, reversed-phase column (Ultra IBD, 100 x 2.1 mm) for chromatographic separation followed by MS/MS detection. Calibration standards were prepared in the range of 0.05 to 40 ppb in reverse osmosis water containing phosphate-buffered saline. The established method was then applied to measure PFAS in various human serum and plasma samples, including a NIST 1950 reference human plasma.
