Detection of perfluorooctanoic acid in water using a microfluidic electrochemical sensor with a molecularly imprinted polymer membrane

Abstract

Perfluorooctanoic acid (PFOA), a persistent and highly toxic member of the PFAS family, poses significant risks to water quality and human health. This study presents the development of a low-cost microfluidic sensor for low-level PFOA detection in water. The sensor integrates a free-standing molecularly imprinted polymer (MIP) membrane synthesized in situ by photopolymerization directly within the microfluidic sensing chamber between two sidewall electrodes, enabling recognition of PFOA through hydrogen bonding and hydrophobic interactions. Chronoamperometric measurements demonstrated stable and concentration-dependent responses, with the optimized sensor achieving a limit of detection (LOD) of 350 ng/L and a limit of quantification (LOQ) of 1,730 ng/L. Matrix-matched validation in diluted municipal tap water highlighted the potential of the platform for PFOA detection in diluted water matrices. The proposed platform offers simplified fabrication, by eliminating electrode pretreatment, and provides a compact and scalable approach for point-of-need monitoring of PFAS in environmental water samples.