Potentiometric detection of AFFFs based on MIP

• Potentiometric detection of AFFFs using molecular imprinted polymer on pencil lead.
• Introduction of methylene blue (MB) into polymer matrix due to ion-pairs of AFFF-MB.
• Specific detection of PFOA, PFOS and 6:2FTS in a range of 10 μM–10 mM.
• Discussion on the interferences and negative response.

Potentiometric detection of fluoro-surfactants formulated in aqueous film-forming foams (AFFFs) is demonstrated using molecular imprinted polymer (MIP) formed on pencil lead. We introduce an ingredient of methylene blue (MB) into the polymer matrix of polypyrrole (PPY) to increase the selectivity due to the formation of ion-pairs of AFFF-MB. Fluoro-surfactants including perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS) and 1H, 1H, 2H, 2H-perfluorooctanesulfonic acid (6:2FTS) are specifically detected in the range of 10 μM–10 mM with the limit-of-detection (LOD) down to ∼100 nM (or ∼41 ppb for PFOA). The interference caused by anionic surfactants of sodium dodecyl sulphate (SDS) and dodecylbenzenesulfonic acid sodium (SDBS) is tested and the negative response is discussed.

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