Development of a poly (alizarin red S)/EDTA/GCE sensor for rapid and reliable monitoring of methyl parathion pesticide

Methyl parathion (MP) is a powerful organophosphate insecticide commonly used in agriculture, but it poses serious risks to both human health and environmental safety. This study presents a highly sensitive electrochemical sensor development based on a glassy carbon electrode (GCE) that has been modified in sequence with Ethylenediaminetetraacetic acid (EDTA) and electropolymerized with poly(Alizarin Red S) (poly(ARS)) for detecting MP. The poly(ARS)/EDTA/GCE was characterized with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The EDTA improves the surface functionality and adhesion, while the redox-active poly(ARS) film aids in electron transfer and offers selective sites for MP interaction. The sensor showed significantly better stability, catalytic performance, and electroactive surface area compared to the unmodified electrode. Under optimized pH of 7.0, the sensor reached a limit of detection (LOD) of 0.5527 μM, a limit of quantification (LOQ) of 1.8425 μM, and a linear range from 0.05 to 140 μM, with a sensitivity of 0.1265 μA/μM. It exhibited excellent analytical capabilities, such as repeatability with a relative standard deviation (RSD) of 2.01 %, reproducibility across five independently crafted electrodes with an RSD of 3.13 %, and operational stability over five days with an RSD of 1.76 %. The practical utility of the sensor was validated through MP recovery studies on fresh vegetable samples, which achieved recoveries ranging from 98 % to 113 %. In summary, the developed poly(ARS)/EDTA/GCE sensor provides an effective and reliable method for monitoring MP in both environmental and food safety contexts.