All samples were sent to the University of Notre Dame to be screened for total fluorine as an indicator of likely PFAS treatment. Dr. Graham Peaslee, in the Department of Physics, measured the total fluorine content of paper products using particle-induced gamma-ray emission (PIGE) spectroscopy. Details on this procedure can be found in Ritter et al. 2017. This technique has been used in other studies of papers and textiles (Schaider et al, 2017, Lang et al, 2016), and validation of the technique with other methods including LC-MS/MS, Total Oxidizable Precursor assay, and Combustion Ion Chromatography can be found in Robel et al. 2017 and Shultes et al. 2019.[1-5] The PIGE method measures surface concentration of fluorine; inorganic standards with known fluorine concentrations were used for calibration and to determine an approximate concentration by weight.
- Schaider, L. A.; Balan, S. A.; Blum, A.; Andrews, D. Q.; Strynar, M. J.; Dickinson, M. E.; Lunderberg, D. M.; Lang, J. R.; Peaslee, G. F., Fluorinated Compounds in U.S. Fast Food Packaging. Environmental Science & Technology Letters 2017.
- Ritter, E. E.; Dickinson, M. E.; Harron, J. P.; Lunderberg, D. M.; DeYoung, P. A.; Robel, A. E.; Field, J. A.; Peaslee, G. F., PIGE as a screening tool for per-and polyfluorinated substances in papers and textiles. Nucl Instr Meth 2017, B407, 47-54.
- Lang, J.; Allred, B.; Peaslee, G.; Field, J. A.; Barlaz, M., Physical and biological leaching of poly-and perfluoroalkyl substances (PFASs) in laboratory-scale anaerobic bioreactors filled with carpet and clothing”. Environ Sci Technol 2016, 50, 5024-5032.
- Robel, A.; Marshall, K.; Dickinson, M.; Lunderberg, D.; Butt, C.; Stapleton, H.; Peaslee, G.; Lang, J.; Barlaz, M.; Field, J., Closing the mass balance of fluorine in papers and textiles. Environ Sci Technol 2017, 51, 9022-9023.
- Schultes, L.; Peaslee, G.; Brockman, J.; Manumdar, A.; McGuinness, S.; Wilkinson, J.; Sandblom, O.; Ngwenyama, R.; Benskin, J., Total fluorine measurements in food packaging: how do current methods perform? Environ Sci Technol Lett 2019, 6 (2), 73-78.