Enhanced electrochemical sensing of methyl parathion using a screen-printed electrode functionalized with...

We report a portable electrochemical sensor for trace detection of methyl parathion (MP) based on a screen-printed electrode (SPE) functionalized with a hierarchical MOF-CoFe₂O₄/Ti₃C₂T _x MXene/carbon nanofibers composite. Structural and surface analyses (XRD, XPS, SEM) confirm successful integration of a spinel CoFe₂O₄, delaminated Ti₃C₂T _x , and graphitic carbon nanofiber into a porous architecture. Electrochemical characterization (EIS, CV, DPV) demonstrates markedly reduced charge-transfer resistance and enlarged electroactive surface area relative to bare SPEs. The sensor shows a well-defined irreversible cathodic peak for MP reduction, with optimal response at pH 7 and diffusion-controlled kinetics. Differential pulse voltammetry yields a linear calibration from 0.015 to 16 µM and a detection limit of 5.8 nM. It exhibited high selectivity against common interferents, good reproducibility (RSD = 1.76%), and sustained stability over 21 days. Critically, the sensor was successfully applied to detect MP in spiked real samples, including tap water, river water, and various vegetables, with reliable recovery rates (95.8-105.0%). These results highlight the potential of the MOF-CoFe₂O₄/Ti₃C₂T _x MXene/carbon nanofibers/SPE as a robust, cost-effective platform for on-site food safety monitoring and environmental surveillance.