Non-enzymatic g-C₃N₄ supported CuO derived-biochar based electrochemical sensors for trace level detection of malathion

Malathion (MALA), a widely used insecticide, even at trace levels exhibits deleterious effects towards respiratory tracts, and nervous system, necessitating its detection. Herein, we have offered non-enzymatic trace level monitoring of MALA using g-C₃N₄ supported CuO-derived biochar. The present B-CuO/g-C₃N₄ based electrochemical sensor is synthesized using hydrothermal approach followed by calcination at high temperature. The result unveiled the strong <pi-pi> interactions, high charge separation efficiency, significant porosity leading to excellent electrochemically active surface area 9.88 × 10^-5 cm² with least charge transfer resistance (R_CT) value of 35.2 K Ω. The B-CuO/g-C₃N₄ based nanocomposite offered excellent complex formation ability with MALA and square wave anodic stripping voltametric method (SWASV) generates an enhanced electrochemical signal due to oxidation of MALA. Following all necessary optimizations, the sensor was capable to exhibit limit of detection (LOD) value of 1.2 pg mL^-1 with R² = 0.968. The modified biosensor offered its potential towards detection of MALA in apple and tomato samples with a recovery ranging from 87.64 to 120.59%. This novel B-CuO/g-C₃N₄ ternary nanocomposite provides non-enzymatic detection of MALA having excellent electrochemical properties and hence opens new pathways for exploring the use of biochar in other electrochemical applications.