Surface molecular imprinting on dye-(NH2)-SiO2 NPs for specific recognition and direct fluorescent quantification of perfluorooctane sulfonate

A perfluorooctane sulfonate (PFOS, C8F17SO3−) molecularly imprinted (MIP) fluorescence sensor was developed by anchoring the MIP polymer on the surface of SiO2 NPs via a surface molecular imprinting process. Fluorescence dye and organic amine were covalently immobilized onto the surface of MIP-SiO2 NPs to form a hybrid monolayer of dye fluorophores and amine ligands which acted as the receptor sites to bind PFOS(C8F17SO3−) species through the acid-base pairing and hydrogen-bond interaction under acid condition (pH ∼ 3.5). The specific binding of PFOS into the recognition cavities in the polymer matrixes results in the fluorescence quenching due to the electron transfer from the fluorescence dye to PFOS. This proposed method can selectively and sensitively detect down to 5.57 μg L−1 of PFOS in water, and a linear relationship has been obtained covering the concentration range of 5.57-48.54 μg L−1 (10.36-90.2 nM).