Assessing Per- and Polyfluoroalkyl Substances (PFAS) in Fish Fillet Using Non-Targeted Analyses
- Instrument: 6560 Q-TOF LC/MS
Bioaccumulation, Lepomis, consumption advisory, mass spectrometry, ion mobility spectrometry
Lab head: Erin Baker
Submitter: Anna Boatman
Per- and polyfluoroalkyl substances (PFAS) are a class of thousands of man-made chemicals that are persistent and highly stable in the environment. The diverse structures of PFAS give them different chemical properties that influence their solubility in different environmental matrices and biological tissues. PFAS in drinking water have been extensively studied, but information on their presence in fish and other exposure routes is limited. To address this, a non-targeted analysis using liquid chromatography, ion mobility spectrometry, and mass spectrometry (LC-IMS-MS) was performed to evaluate PFAS in fish fillets from in central North Carolina and compare with PFAS data from previously published water. A total of 22 different PFAS were detected in the fillets, including only 4 of the PFAS reported in water. Both more PFAS types and higher concentrations were observed in fish caught near a known PFAS point-source compared to those from a reservoir used for drinking water and recreation. Median fillet PFOS levels were 54 ppb in fish closest to the point source and 14-20 ppb in fish from the reservoir. Thus, future PFAS monitoring should include both targeted and non-targeted analyses of both water and fish to increase understanding of human exposure risks and ecosystem impacts.
Sunfish fillets were collected from 5 sites in North Carolina in the summer of 2020. A stable isotope-labeled PFAS standard mix (MPFAC-HIF-ES) was obtained from Wellington Laboratories (Guelph, Canada) containing heavy-labeled PFAS at varying concentrations from 250 to 5,000 ng/ml in methanol. The mix was diluted 1:1 in methanol for use as internal standard. Optima LC-MS grade methanol, water, and ammonium acetate were used for extractions and mobile phases (Fisher Scientific). The Standard Reference Material 1947 (SRM1947, Lake Michigan Trout) was also obtained from NIST and used for quality control. Fish fillet samples, quality control samples (0.5 g SRM1947), and method blanks (0.5 mL water) were homogenized in a bead mill. Sample wet weights for the fish fillets ranged from 0.1 to 1 g. The homogenized tissue was spiked with internal standards (5 µL) and extracted in methanol (5 mL) with 1 hr sonication followed by centrifugation, syringe filtration, and dispersive carbon treatment. Extracts were concentrated to dryness in a speedvac and reconstituted in 200 µL of 40% methanol, 60% water by volume buffered with 3 mM ammonium acetate. Reconstituted samples were transferred to polypropylene LC vials with inserts.
1001-1057: extracted fish fillet samples
MB01-03 and BB01: method blanks (water extracted along with the fish fillets)
DB1-2: double blanks (reconstitution buffer in LC vial)
SIL: standard blanks (internal standard spiked into reconstitution buffer)
QC01-04: quality control (NIST SRM 1947 fish tissue homogenate)
Created on 9/1/23, 3:26 PM