Ultrasensitive and Selective Analysis Monitoring of Multiple PFAS in Environmental Water Samples Using a Photoelectrochemical Sensing Platform

Per- and polyfluoroalkyl substances (PFAS), as a class of environmentally persistent pollutants, have aroused significant concerns owing to their serious negative effects on human health, even at nanogram-level concentrations. Robust, ultrasensitive, and selective technologies are urgently needed to detect PFAS in environmental water. Herein, a photoelectrochemical (PEC) sensing platform was developed by the immobilization of an anti-PFAS aptamer onto Bi2S3 nanowires/WO3 nanosheet arrays (Bi2S3 NWR/WO3 NSA) for the detection of the three target PFAS compounds, including perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), and perfluorohexanesulfonic acid (PFHxS). The superior performance of the PEC sensing technique lies in its ability to ultrasensitively and selectively detect the three target PFAS compounds with ultralow concentrations in environmental water by combining the Bi2S3 NWR/WO3 NSA photoactive electrode with outstanding PEC response characteristics and a highly specific anti-PFAS aptamer. In the presence of target PFAS, the photocurrent response of the sensing platform changes as the recognition events of aptamer toward target PFAS proceed, attributing to the fact that the formed aptamer-PFAS complexes on the sensing surface reduce the electron transfer ability. Target PFAS could thus be quantitatively detected by establishing the correlation between photocurrent response and concentrations. Meanwhile, the sensing platform exhibits strong resistance to interference. Furthermore, its practical applicability was demonstrated through the determination of target PFAS levels in diverse environmental water samples. Therefore, the prepared PEC sensor would provide a new approach for the monitoring of low-concentration PFAS.