Molecularly Imprinted SPR Sensor for Sensitive and Selective Detection of Pb2+-Ions

Abstract

Lead contamination poses a significant risk to environmental and human health, necessitating sensitive and reliable detection strategies. Here, a Pb2+-ion-imprinted surface plasmon resonance (SPR) sensor was developed by constructing a coordination-driven recognition layer directly on a gold surface. Surface characterization confirmed the successful formation of the imprinted polymeric layer and the presence of metal–ligand interactions within the polymer matrix. The sensor enables real-time detection of Pb2+-ions over the 5–100 ppb range, with a low detection limit (LOD = 3.079 ppb) and quantification limit (LOQ = 9.331 ppb) and good linearity. The binding behavior follows the Freundlich isotherm, indicating heterogeneous recognition sites generated during the imprinting process. Selectivity studies demonstrate that Pb2+-ions recognition is governed by coordination-based interactions, allowing effective discrimination against competing metal ions. The sensing performance remains stable in artificial wastewater, highlighting robustness in complex matrices. These results present a reliable and sensitive SPR platform for real-time monitoring of trace-level Pb2+-ions, offering strong potential for environmental applications.