Electrochemically pretreated graphite:glass thick films for ultra-trace detection of neonicotinoids in surface water and honey

Neonicotinoids (NNIs) pose a significant threat to pollinator populations and environmental health due to their widespread use and adverse effects on non-target organisms. Despite regulatory efforts, monitoring of NNIs in natural ecosystems remains challenging. In contrast to conventional chromatographic methods, integrated electrochemical sensors provide a rapid and on-site detection of NNIs. In this study, we report on a novel voltammetric sensor based on the electrochemical pretreatment of an in-house screen-printed graphite:glass electrode for a sensitive and selective detection of clothianidin (CLO), imidacloprid (IMI), and thiamethoxam (TMX). Electrochemical characterization via cyclic voltammetry and impedance spectroscopy demonstrated a significant enhancement in electrode performance after the pretreatment, offering strong adsorption properties and detection limits in the nanomolar level, achieving the lowest reported LODs for CLO (26 nmol L −1 ) and IMI (12 nmol L −1 ). For all three NNIs, two linear ranges between 0.5 and 40 μmol L −1 were observed, alongside great sensitivity (8.1–13.1 μA μmol −1 L, depending on the analyte). Notably, the recoveries obtained for NNIs in surface water and honey samples, ranging from 96.3 % to 107.8 %, indicate its applicability for real-sample and on-field monitoring. Utilizing one-step voltammetric electrode pretreatment and adsorption-based pre-concentration offers a cost-effective, fast, and ultra-sensitive platform, thus addressing a critical need in environmental analysis and pesticide regulation