With worldwide concern growing over the emerging persistent contaminates known as Per- and poly-fluorinated alkyl substances (PFAS) there is a distinct need for affordable and reliable detection tools. As part of my ongoing research as a trainee of the STEEP Superfund Center, I am in the process of validating a novel tube passive sampler that will be used to measure PFAS contamination in surface and ground waters. Current work has focused on validating the uptake of PFAS across environmental conditions like flow, water temperature, and presence of biofouling using a microporous polyethylene tube filled with a commercially available sorbent used as the receiving phase for PFAS. While the current sorbent is commonly used for PFAS extraction, a novel cyclodextrin sorbent designed for PFAS remediation, could boast higher sorption for a wider range of PFAS, thus improving uptake of PFAS within the walls of this tube passive sampler. To test this, I propose travelling to the private company that produces this cyclodextrin sorbent, Cyclopure Inc. in Skokie IL, to validate a method for extraction of both native and mass labeled surrogate compounds from my passive samplers, loaded with their sorbent. Cyclopure Inc. is a working under an SRP-funded grant (R43ES029401), and their novel sorbent called DEXSORB+, was created for remediation of PFAS while being re-useable. This novel sorbent is also more affordable than the currently used sorbent, costing about 20 times less per 50 grams of sorbent. In addition to validating an extraction method for a wider range of PFAS standards than available in my current laboratory at the University of Rhode Island, I will gain direct mentorship while analyzing my own samples on Cyclopure?s Liquid Chromatograph/Mass Spectrometry instrument. With limited access to this instrument at my university, I will have valuable time to learn operation, troubleshooting, and data analysis under the guidance of Matt Notter and Frank Cassou of Cyclopure Inc. Through this experience, I will get the unique opportunity to learn about the skills that interests private sector companies before graduating from my doctoral program. Follow up collaborations using passive samplers with state and federal agencies will give me broad exposure to many career paths that I will consider as I finish my studies. The expected outcome of this externship will be an improved design for a passive sampler for PFAS in surface and ground waters that will be affordable, reusable, and reliable for all stakeholders. These results will be shared at the SRP annual meeting following the completion of the externship, which will allow for a wide variety of stakeholders to be introduced to this potential tool for PFAS measurements.