Thermal determination of perfluoroalkyl substances in environmental samples employing a molecularly imprinted polyacrylamide as a receptor layer
Fatemeh Ahmadi Tabar, Joseph W. Lowdon, Manlio Caldara, Thomas J. Cleij, Patrick Wagner, Hanne Diliën, Kasper Eersels, Bart van Grinsven
Abstract
Polyfluoroalkyl substances (PFAS) have gained increasing negative attention in recent years owing to their potential carcinogenicity, neurotoxicity, and ability to bio-accumulate in wildlife, making their rapid and low-cost detection highly desirable. Molecularly Imprinted Polymers (MIPs) were therefore implemented as robust, cost-effective, and highly selective affinity reagent in a thermal sensing platform (the “Heat Transfer Method”), enabling the development of a time-efficient sensor that is capable of analyzing both river water and soil samples. To this end, a MIP was synthesized for the detection of perfluorooctanoic acid (PFOA) with an optimized rebinding capacity of 123μmol g−1 and an imprinting factor of 2.1 as determined by UV–Vis spectrophotometry. Integration of the MIP into the thermal readout platform revealed a calculated limit of detection (LoD) of 22 pM in controlled buffer solutions. The sensor is able to distinguish PFOA from other PFAS and detect the compound in a mixture of PFAS, providing a proof-of-concept towards the desired application, the specific detection of PFOA in complex samples. To further illustrate the performance of the sensor in this sense, it was exposed to spiked (0.1 nM–500 nM) river water and soil samples, with a calculated LoD of 91 pM and 154 pM respectively. These findings highlight that the developed sensor has the potential to operate at a relevant sensitivity for the analysis of both aqueous and solid environmental samples, facilitating a more straightforward method of screening for PFAS against more complex and time-consuming methodologies.