I am looking for the best liquid adsorbent to bubble vapors through - the goal is to transfer the PFAS, precursors and other organics into the fluid while bubbling vapor/air through it. The fluid must be pure (free of PFAS) and not volatile
I'm not sure if this is what you're looking for, since it's not a pure liquid, exactly, although it would be free of PFAS: in my work, I've seen that activated carbon works very well at sorbing PFAS with high efficiency. I'm also aware that there are several manufacturers who produce activated carbon dispersions. Bubbling PFAS containing gas through the liquid dispersion should transfer organics to the suspended particles, which could later be desorbed or quantified.
Another method that I'm aware of is ion transfer, but may not be suitable based on your problem description.