An estimated 4700 chemical compounds are classified as PFAS. 20 of these have been targeted in the EU Drinking Water Directive 2020/2184 due to their toxicity. They are strongly suspected of causing liver damage, thyroid disease, adiposity, fertility disorders, and cancer.
The EU Drinking Water Directive (EU 2020/2184) includes maximum limits for total PFAS of 0.5 µg/L.
For the sum of 20 PFAS of most concern the maximum limit is 0.1 µg/L, which requires a limit of detection of (LOD) of 30 ng/L for the sum and 1.5 ng/L for the individual compounds.
Even when using a modern triple quadrupole HPLC-MS system, a concentration step is required.
A GERSTEL MultiPurpose Sampler (MPS) and GERSTEL SPExos Online-SPE coupled directly to an LC-MS/MS system can determine PFAS at the required levels by direct injection of water samples. The system is fully automated. Solid phase extraction (SPE) is used as specified in the DIN 38407-42 method.
The DIN method list of analytes can easily be expanded to include those in the EU Drinking Water Directive. Key benefits are simplified sample handling, very low solvent consumption, and excellent accuracy and reproducibility.
Successful participation in a round robin demonstrates the high quality of results achieved: “RV 7/22 PFAS nach EU-TrinkwasserRichtlinie“ (RV 7/22 PFAS in accordance with the EU Drinking Water Directive).
Due to the anionic properties of the analytes to be determined, weak anion exchange (WAX) resins are used.
Following analyte concentration, the SPE cartridges are rinsed with solvent and eluted with a solution of ammonia in methanol resulting in analyte focusing on the column head for improved LC separation and MS/MS detection.
The SPE cartridge can be replaced after each analysis to eliminate carryover.