Curcumin-modified multi-walled carbon nanotubes@zirconia nanocomposite for sensitive electrochemical determination of methyl parathion in fruit juice

Methyl parathion (MP), an organophosphorus pesticide, exhibits potent insecticidal activity. However, the high toxicity of MP residues poses a serious threat to the environment and food safety. To achieve highly sensitive detection of MP, an electrochemical sensor was developed utilizing a composite modifier comprising multi-walled carbon nanotubes (MWCNTs), zirconia (ZrO 2 ), and curcumin (CM). MWCNTs provide a three-dimensional interconnected carbon conductive network. Owing to their inherent high electrical conductivity and large specific surface area (derived from their one-dimensional hollow nanostructure), this network accelerates electron and ion transport. ZrO 2 nanoparticles exhibit specific affinity for phosphorus-containing functionalities (including P S) within MP molecules, promoting analyte enrichment; the electropolymerized curcumin forms a redox-active mediator layer that facilitates MP reduction. This synergistic combination results in superior sensing performance. Under optimized conditions, the developed MWCNTs@ZrO 2 /CM sensor exhibits a linear detection range for MP from 0.01 to 10 μM and achieves a limit of detection (LOD) of 7.13 nM (S/N = 3). The fabricated sensor demonstrated excellent repeatability and reproducibility. Moreover, the sensor displayed high accuracy and practicality for MP determination in real fruit juice samples, underscoring its potential for food safety monitoring.