An electrochemical AChE-based biosensor for organophosphate pesticides using a modified CuNWs/rGO nanocomposite on a screen-printed carbon electrode

•Amplified SPCEs: CuNWs/rGO enhance chlorpyrifos detection via AChE inhibition.•Detection range: 10–200 µg/L, LOD: 3.14 µg/L, LOQ: 12.5 µg/L for chlorpyrifos.•Versatile analysis: water, orange juice; high recoveries, no interference. An enzymatic electrochemical biosensor was built for the indirect detection of organophosphates (OPs), based on acetylcholinesterase inhibition. The biosensor was fabricated for enhanced performance on a screen-printed carbon electrode (SPCE), modified with copper nanowires (CuNWs) composited with reduced graphene oxide (rGO). The oxidation current was measured using the cyclic voltammogram (CV) method, as generated by the enzymatic interaction between acetylcholinesterase (AChE) and its substrate, acetylthiocholine (ATCh). The biosensing response is the reduction in signal caused by the inhibition of acetylcholinesterase in the presence of an organophosphate inhibitor. Benchmarking shows that the CuNWs/rGO nanocomposite enhanced the signal current considerably and decreased the oxidation potential for electrochemical detection of the OP chlorpyrifos, exhibiting a wide linear detection rangefrom 10 µg/L–200 µg/L, with a limit of detection of 3.1 µg/L and limit of quantification of 12.5 µg/L. This sensor is useful for the analysis of chlorpyrifosin drinking water and orange juice, with high recovery rates and no interference effects.