Acetylcholinesterase biosensor based on electrochemically inducing 3D graphene oxide network/multi-walled carbon nanotube composites for detection of pesticides

摘要

A sensitive electrochemical biosensor for determining organophosphates (OPs) and carbamate pesticides has been achieved by immobilizing acetylcholinesterase (AChE) on electrochemically inducing 3D graphene oxide network/multi-walled carbon nanotube composites (e-GON–MWCNTs). The nanocomposites of e-GON–MWCNTs can provide a favorable environment for the immobilized AChE and improve the electron transfer speed between the analyte and electrode surface. The fabricated AChE biosensors show a favorable affinity to acetylthiocholine chloride (ATCl) with a Michaelis–Menten constant of 0.43 mmol L?1. In the optimal conditions, the biosensor exhibits a linear range of 0.03–0.81 ng mL?1 for detecting carbofuran, and two linear ranges of 0.05–1 ng mL?1 and 1–104 ng mL?1 for detecting paraoxon. Furthermore, the detection limits for carbofuran and paraoxon can reach 0.015 and 0.025 ng mL?1, respectively. The AChE biosensor exhibits good reproducibility and high stability, which demonstrates good efficiency in real sample analysis.