{"id":35915,"date":"2025-08-28T17:57:50","date_gmt":"2025-08-28T17:57:50","guid":{"rendered":"https:\/\/discover.restek.com\/?p=35915"},"modified":"2026-04-08T19:29:26","modified_gmt":"2026-04-08T19:29:26","slug":"what-is-the-concentration-on-my-pfas-standardss-cofa","status":"publish","type":"post","link":"https:\/\/discover.restek.com\/de\/faq-it\/gnot4956\/what-is-the-concentration-on-my-pfas-standardss-cofa","title":{"rendered":"What is the concentration on my PFAS standard’s CofA?"},"content":{"rendered":"\n

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 \u201cCompound\u201d and \u201cCAS #\u201d fields on your certificate. In the example below, you can see that PFOSK was used as the raw material. The concentration listed in the \u201cGrav. Conc.\u201d 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 \u00b5g\/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?<\/a>” for more information.<\/p>\n\n\n

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Excerpt from PFOS standard (cat.# 30802<\/a>) certificate of analysis.<\/em><\/p>\n\n\n\n

See our\u00a0PFAS compound cross-reference<\/a>\u00a0for additional CAS #s of various salts and conjugate acids.<\/p>\n\n\n\n