MoS2/PPy Core–Shell Nanocomposite-Modified Glassy Carbon Electrode for Electrochemical Detection of Chlorpyrifos

In this study, a MoS 2 /polypyrrole (PPy) nanocomposite sensing film was constructed in situ on a glassy carbon electrode (GCE) surface via chemical oxidative polymerization. The synergistic coupling of high-surface-area layered MoS 2 and conductive PPy not only significantly increased the effective electrochemical active area of the electrode but also generated multiple affinity interactions toward chlorpyrifos (CPF) molecules through the edge-active sites of MoS 2 and the π -conjugated structure of PPy, endowing the composite film with prominent adsorption-enrichment capability and excellent selectivity for CPF. Upon enrichment of CPF, the specific interactions between the organophosphate groups and the MoS 2 /PPy interface modulated the electron transfer kinetics of the composite film, producing quantifiable electrochemical signals proportional to the pesticide concentration. Under optimized conditions, the proposed sensor achieved a low detection limit of 1.10 μg/L for CPF and exhibited outstanding anti-interference capability and favorable operational stability in complex agricultural product matrices. Real sample analysis demonstrated that the spiked recoveries ranged from 97.69% to 100.83%, with RSD values of 2.34%–3.53%, verifying the excellent accuracy and reliable analytical performance of the as-prepared material. This work provides a novel nanocomposite sensing material for organophosphorus pesticide residue detection and manifests great application potential in agricultural product quality and safety monitoring.