GRAPHITIC CARBON NITRIDE FUNCTIONALIZED NICKEL CERIUM BIMETALLIC OXIDE FOR ULTRASENSITIVE DETECTION OF TRICHLORFON

Abstract

Organophosphate pesticides are widely used in agriculture to protect crops from pest damage; however, excessive use contaminates soil, water, and food products, posing serious environmental and health risks. Trichlorfon (TF), an organophosphate pesticide, strongly inhibits the enzyme acetylcholinesterase (AChE), disrupting the nervous system. Therefore, the development of a rapid and sensitive method for TF detection is highly important to food safety and environmental monitoring. In this study, we report the fabrication of an electrochemical biosensor based on AChE immobilized on a Ce-NiO@g-C3N4 nanocomposite-modified indium tin oxide (ITO) electrode for ultrasensitive detection of TF. The Ce-NiO@g-C3N4 nanocomposite provides excellent electrical conductivity, large surface area, enhanced electron transfer, and superior electrocatalytic activity, which facilitate efficient enzyme immobilization and improve sensing performance. Glutaraldehyde was used as a crosslinking agent to enhance enzyme stability and prevent leaching from the electrode surface. The fabricated AChE/Ce-NiO@g-C3N4/ITO biosensor exhibited high sensitivity (5.412 µAµM⁻¹cm⁻²), excellent stability, good reproducibility, and strong anti interference capability for TF detection over a wide linear range, with a low detection limit of 0.1 pM. Furthermore, the developed biosensor was successfully applied to the determination of trichlorfon residues in real agricultural samples, including apple, cucumber, and rice, demonstrating satisfactory recovery and practical applicability. The proposed biosensor offers a simple, rapid, cost-effective, and highly efficient platform for monitoring organophosphate pesticides in food and environmental samples.