Per- and polyfluoroalkyl substances (PFASs) constitute a diverse class of principally anthropogenic chemicals which have been manufactured globally for over 60 years. Perfluoroalkyl acids (PFAAs) are the most commonly studied class of PFAS, owing to their ubiquitous occurrence in the global environment, along with considerable persistence, bioaccumulation potential, and adverse health effects in lab animals. PFAA sources are numerous and not well characterized. In addition to emissions arising from direct manufacture and use, PFAAs may form from both abiotic and biologically-catalyzed transformation of other PFASs (i.e. PFAA-precursors). Examination of historical production data indicate that humans and wildlife may receive a significant proportion of their PFAA exposure from precursors. Despite the potential importance of precursors, routine monitoring tends to focus solely on a suite of PFAAs, in part due to a lack of analytical methods for measuring the numerous PFAA-precursors known to exist. This project represents a collaboration between ACES and the Swedish Naturhistoriska riksmuseet (NRM). The objective is to develop an advanced oxidation approach for characterizing known and unknown PFAA-precursors in wildlife samples. The methodology follows a similar approach for water and soil samples, which is gaining widespread adoption for characterizing precursors. This work will support ongoing monitoring efforts in wildlife fish, birds, and marine and terrestrial mammals.