Total organofluorine (TOF) testing for PFAS
The screening method for PFAS — what it measures, what it doesn't, and when to follow up with targeted testing.
Most state PFAS laws don't list specific chemicals to test for. They restrict PFAS as a class, usually PFAS that were intentionally added. A total organic fluorine (TOF) test screens for PFAS as a class by measuring organic fluorine, without identifying the individual compounds. Targeted testing then identifies which specific PFAS are present.
What TOF doesn't tell you:
- Which specific PFAS are present
- Whether the PFAS was intentionally added or is incidental contamination
- On its own, whether the product meets a particular state's rule
Where a fluorine measurement itself matters:
- California textile articles — PFAS present at or above 100 ppm total organic fluorine (from January 1, 2025) or 50 ppm (from January 1, 2027) count as regulated PFAS, whether or not anyone added them on purpose (Health and Safety Code 108970(g)). This threshold is in California's textile law only.
- Washington — for several restricted product categories, Ecology presumes that total fluorine detected above 50 ppm indicates intentionally added PFAS (WAC 173-337-110).
- Minnesota — the report to the MPCA asks for the amount of each PFAS by CAS number (Minn. Stat. §116.943, subd. 2), which a TOF screen alone can't give you.
Targeted testing: ask your lab which method it uses for your product's material, and why. EPA Methods 533 and 537.1 are drinking-water methods (40 CFR 141.901), not methods for testing a product.
WARNING: Don't assume a PTFE coating is outside PFAS laws. Maine, for example, defines PFAS as any fluorinated organic chemical containing at least one fully fluorinated carbon atom (38 MRSA §1614(1)), and cookware with intentionally added PFAS is banned in Minnesota (from January 1, 2025) and Colorado (from January 1, 2026).