Electrochemical approaches to glyphosate detection using molecularly imprinted polymer-coated metal-organic frameworks

Abstract

Glyphosate (GLY) is one of the most commonly used herbicides worldwide. Its widespread use raises significant concerns about public health and ecological integrity, which have led to increased control and oversight of its use, along with a growing demand for rapid and reliable monitoring. This study presents a novel electrochemical sensing platform designed for detecting GLY, utilizing the unique properties of multifunctional rare-earth metal-organic frameworks (RE-MOFs) alongside with the selective recognition capabilities of molecularly imprinted polymer (MIP) technology. The composite formed from yttrium-2-aminoterephthalic acid-based MOF and graphene oxide modifies the surface properties of a glassy carbon electrode (GCE) and serves as a support substrate for the subsequent preparation of the MIP. The crystallinity and flower-like architecture of the resulting composite, were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), while charge-transfer properties and conductivity were characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The selection of the appropriate MIP for GLY detection was driven by advanced theoretical calculations, that focused on the interactions between diverse functional monomers and GLY. Theoretical determination of the optimal monomer was followed by experimental optimization of the electropolymerization method for the preparation of MIP/MOF sensors. The resulting sensor demonstrated a wide dynamic linear range (1–16 542 nM) and a subnanomolar detection limit (0.42 nM). It exhibited good specificity and an excellent recovery rate in practical applicability for water samples. The obtained results highlight the potential of the proposed sensing platform for environmental monitoring applications