19F solid-state nuclear magnetic resonance as a tool to study the bioaccumulation of per- and polyfluoroalkyl substances in murine tissue samples

Many per- and polyfluoroalkyl substances (PFAS) are known to be persistent in the environment and are associated with adverse health effects including kidney and liver disease and developmental toxicity. While PFAS are also known to have high bioaccumulation potential, whether these compounds can be detected in biological tissue using nuclear magnetic resonance (NMR) has not been established. In this study, we used ¹⁹F solid-state magic angle spinning (MAS) NMR to investigate the accumulation of a legacy PFAS, perfluorooctanoic acid (PFOA), in murine tissue samples including the adult brain, intestine, kidney, liver, uterus, adipose tissue, placenta and fetal brain. Healthy pregnant (n = 4) and non-pregnant (n = 5) female CD-1 mice were exposed to 50 ppm of PFOA through their drinking water for 17 days. PFOA was detected above the limit of detection (10 μg g⁻¹) in all of the liver samples (n = 9/9), 25% (n = 2/8) of the adipose tissue samples, 33.3% (n = 4/12) of the male placenta samples, and 16.7% (n = 2/12) of the female placenta samples. The detection of PFOA in adipose tissue challenges the current understanding about the behaviour of PFAS in the human body. These results demonstrate that ¹⁹F solid-state MAS NMR is a promising tool for detection and quantification of PFAS in tissue samples and motivate further work to evaluate accumulation of unregulated, emerging PFAS that have different chain lengths and head groups.