A sensitive amperometric AChE-biosensor for organophosphate pesticides detection based on conjugated polymer and Ag-rGO-NH2 nanocomposite.

Long-term accumulation of organophosphate pesticides in environment presents a potential hazard to human and animal health. Towards this, a highly sensitive amperometric AChE-biosensor based on conjugated polymer and Ag-rGO-NH2 nanocomposite has been successfully developed. First, 4, 7-di (furan-2-yl) benzo thiadiazole (FBThF) was electrochemically polymerized on the electrode surface. Then, Ag-rGO-NH2 nanocomposite and acetylcholinesterase (AChE) are modified on the polymer membrane surface. In this way, a novel amperometric AChE-biosensor was successfully prepared. The as-prepared biosensor possessed excellent conductivity, catalytic activity, and biocompatibility which were attributed to the synergistic effects of poly(FBThF) and Ag-rGO-NH2 and provided a hydrophilic surface for AChE adhesion. Under optimized conductions, the linear range was 0.099-9.9 μg L-1 with a regression coefficient of 0.9947 for malathion, 0.0206-2.06 μg L-1 with a regression coefficient of 0.9969 for trichlorfon. The detection limit is calculated to be about 0.032 μg L-1 for malathion and 0.001 μg L-1 for trichlorfon (S/N = 3). Moreover, the biosensor exhibited acceptable reproducibility and long-term stability, which makes it possible to provide a novel and promising tool for analysis of organophosphate pesticides.