Restek PFAS materials are >99% pure. Some PFAS raw materials are utilized in their salt form to manufacture products; for example, Potassium Perfluorooctanesulfonate (PFOSK) is used to manufacture the Perfluorooctanesulfonic acid (PFOS) standard. To verify if the salt form of the raw material was used, simply check the “Compound” and “CAS #” fields on your certificate. In the example below, you can see that PFOSK was used as the raw material. The concentration listed in the “Grav. Conc.” field on your certificate of analysis (CofA) has been corrected for the salt content of the raw material and thus is the concentration of the compound as the acid. For example, the 99.4 µg/mL concentration stated in the example is that of Perfluorooctanesulfonic acid (PFOS). For salt correction details, refer to “Are your reference standards weight corrected for purity?” for more information.
Excerpt from PFOS standard (cat.# 30802) certificate of analysis.
See our PFAS compound cross-reference for additional CAS #s of various salts and conjugate acids.
