Fluorinated antifouling imprinted polymer platform for electrochemical selective detection of perfluoroalkyl and polyfluoroalkyl substances.

Abstract

Perfluorooctane sulfonates (PFOS) commonly coexists with other PFAS in aquatic matrices, making selective recognition challenging in complex water samples. In this study, we developed a fluorination-engineered surface molecularly imprinted electrochemical sensor (Po-PD-F SMIP) for the highly selective detection of PFOS. The sensing layer was formed by electropolymerizing o-phenylenediamine on a PFDT-functionalized interface. PFOS was selectively captured through synergistic spatial matching within the MIP cavities and fluorinated interface interactions between the perfluorinated chains of PFOS and PFDT. The PFDT-containing interface also provided antifouling behavior through fluorinated interfacial while maintaining electron-transfer pathways. PFOS rebinding caused a pronounced decrease in the differential pulse voltammetry (DPV) response of the [Fe(CN)6]3-/4- redox probe owing to competitive adsorption and hindered electron transfer. The optimized sensor exhibited excellent linearity over a wide dynamic range from 0.05 ng mL-1 to 500.1 μg mL-1 (R2 = 0.9903), with a low limit of detection (LOD) of 12.1 ng L-1. Compared with the Po-PD sensor, incorporation of the PFDT probe increased the imprinting factor by 2.43-fold and enhanced the binding affinity by approximately 102.8-fold. The sensor exhibited an IF of 11.99 for PFOS, 4.28-8.75 times higher than those for other perfluorinated analogues. It was also successfully applied to real water samples, with satisfactory recoveries and good agreement with LC-MS/MS results. This study provides a promising approach for rapid, sensitive, and reliable on-site monitoring of trace PFOS in complex water samples.

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