PFAS – Total oxidizable precursors (TOP) in products and waste
A growing number of PFAS substances and matrices are subject to regulation. In 2023 the POP regulation ((EU) 2019/1021) was extended to include, besides PFOS, limit values for PFOA and PFHxS regarding products and waste. Moreover, PFOA and PFHxS "related" substances are covered and for PFOS “derivatives”, all with separate limits. These additions significantly widen the scope and there are associated lists with several hundred examples. Another development is the proposal for a general PFAS group restriction (ECHA) where both single as well as the sum of all individual PFAS are to be assessed. For the sum, the measurement may include an oxidative conversion of precursors. Besides the POP regulation it should be noted that already existing REACH legislation for C9-C14 PFCA (perfluorinated carboxylic acids) and the expected for PFHxA, both regulate “related” compounds too. Another restriction in progress is the ECHA ban of PFAS in fire fighting foam (AFFF). Modern foams are almost entirely based on larger molecules, frequently 6:2 fluorotelomer based, that can degrade to PFAS that are commonly measured i.e. the AFFF content can in those cases be looked upon as “related” substances.
Both “related” substances and “derivatives” are most of the time so-called precursors. Precursors can as final degradation products form PFCA and PFSA (perflourinated sulfonic acids) in natural systems. Since there are thousands of different PFAS substances, the precursors make up a very broad group of both known and unknown compounds. Among the more known, e.g. PFOSA, EtFOSE 6:2 and 8:2 FTS (fluorotelomer sulfonates) can be mentioned.
In addition, precursors can be oxidized chemically to the corresponding perflourinated substances, typically PFCAs, and this is what takes place during TOP analysis. TOP can be used to assess the “type” of many “related” substances, “derivatives” and precursors after evaluation of the results, and also yield quantitative data. In some cases TOP can be used more as a tool for qualitative indications e.g. for side-chain co-polymers. The results may motivate further studies och possibly more exact identification of precursors. TOP can also be used as a means of oxidative conversion for comparison to the sum of individual PFAS in the proposed general ECHA PFAS restriction. We strongly recommend that a "regular" PFAS analysis is performed at the same time as TOP both to facilitate a comparison before vs after and of quality reasons. In many cases there is also a need to evaluate individual PFAS with limit values (PFOS, PFOA etc).
Eurofins now introduces two packs for TOP in products and waste. One package corresponding to DK PFAS22 used for soil, building material, sludge, water etc and a larger screening pack. The reporting limit (LOQ) is between 5-10 μg/kg with the lower value seen for the majority of compounds. The required sample weight is 10g or more. The delivery time (TAT) is 10 working days. Please note that sample preparation (milling, crushing) is not included and might have to be added (SL004), and in such cases more material is needed.
New TOP packs for products and waste:
PLWC0: DK PFAS22 (TOP)
PLWB3: PFAS38 screening pack (TOP)
“Regular” packs for products and waste:
PLW8E: DK PFAS22
PLWB0: PFAS33 experience based and regulation
PLWD5: PFAS50 screening pack
Contact Eurofins experts!
Questions about PFAS can be answered by our analytical advisory service, which can be reached via the customer support, 010-490 8110 or e-mail: sh-analys.miljo.se@etn.eurofins.com
Links
POP regulation ((EU) 2019/1021)
ECHA (Restrictions Annex XVII)
ECHA (Proposed general PFAS restriction)
ECHA (firefighting foam restriction)