Cobalt-modified exfoliated zirconium phosphate/histidine-functionalized graphene quantum dots-based electrochemical biosensor for promoting sensitive detection of methyl parathion in agricultural foods and water bodies samples.

The detection of methyl parathion (MP) is of critical importance due to its high toxicity and widespread use as an organophosphate pesticide. Therefore, the monitoring and the rapid quantification of MP are essential for ensuring food safety and promoting sustainable farming practices, which minimize potential health risks to consumers. Effective detection strategies can aid in reducing exposure and mitigating the impact on human health and ecosystems. In this study, cobalt-modified exfoliated zirconium phosphate (Co-ExZrP) coated on histidine-functionalized graphene quantum dots (His-GQDs) was synthesized and integrated onto screen-printed silver electrode surface to develop an electrochemical biosensor for the electrochemical determination of MP. Moreover, a synergistic electrocatalysis approach integrating Co-ExZrP and His-GQDs was also presented. The Co-ExZrP possessed the greater surface accessibility, the higher loadings of Co electrocatalyst material, and the improved site access for electrocatalysis whereas His-GQDs facilitated outstanding electron transfer efficiency, thereby improving the MP detection performance. Under optimum conditions, the sensor exhibited a linear range of 0.2-50 μM with a high coefficient of determination (R = 0.9905), low detection limit of 0.01 μM (signal-to-noise ratio = 3), and high sensitivity of 0.85 mA (μM)‾ demonstrating the superior sensing performance. The applicability of the electrochemical biosensor constructed by Co-ExZrP/His-GQDs for food safety monitoring was investigated in pear and apple samples as well as in various water matrices, including drinking and groundwater samples, through MP analysis, implying the sensitive and efficient electrochemical strategy as well as good application potential in MP monitoring.