Conjugated polymer nanoparticle-enhanced molecularly imprinted poly(o-phenylenediamine) electrochemical sensors for selective, sensitive and rapid detection of trace perfluorooctanesulfonate

Abstract

Perfluorooctanesulfonate (PFOS), a representative persistent organic pollutant, demands rapid and sensitive detection methods to support environmental protection and health risk assessment. In this work, a conjugated polymer nanoparticle (CPNP)-enhanced molecularly imprinted poly(o-phenylenediamine) electrochemical sensor (CPNPs-MIP-PoPD/GCE) was developed for selective and ultrasensitive detection of trace PFOS. The spherical CPNPs were found to establish intermolecular interactions with PFOS molecules, while their integration into the PoPD matrix synergistically increased the sensor's effective surface area and improved its PFOS enrichment capacity. The optimized sensor enabled rapid detection (25 s) of PFOS in the range of 0–2.5 nM with a remarkably low detection limit of 0.0037 nM (S/N = 3) and excellent sensitivity (0.6605 μA nM⁻¹), representing an order-of-magnitude improvement over the non-CPNP-modified counterpart (0.0446 nM). Notably, this method achieved satisfactory PFOS recoveries (95.6–103.2%) in real water samples without requiring complex pretreatment procedures. The developed sensing platform combines high sensitivity with cost-effectiveness, demonstrating substantial potential for on-site monitoring of PFOS contamination in environmental systems.