AChE inhibition sensing through SiO₂ and GQDs interface on screen-printed electrode for malathion detection

Abstract

Organophosphorus pesticides like malathion, adversely affect and cause significant risks to human health and the environment. Conventional detection methods are often pricey and tedious and need specialists. In this study, an electrochemical biosensor for malathion detection was developed using acetylcholinesterase (AChE) inhibition. The sensor was created by modifying a screen-printed electrode with silica nanoparticles (SiO₂) and graphene quantum dots (GQDs), followed by the immobilization of AChE. Square wave voltammetry was used to evaluate of the sensor performance using acetylthiocholine chloride (ATCl) with a detection range of 40–100 pM with a significant current difference of 9 µA. The biosensor demonstrated a sensitivity of 0.10 µA/pM for the substrate ATCl and achieved a detection limit of 0.01 ppm for malathion. It effectively detected malathion in various vegetable samples, highlighting its potential for on-site pesticide monitoring and rapid detection.