Electrochemically reduced graphene oxide and Nafion nanocomposite for ultralow potential detection of organophosphate pesticide

The development of rapid and field monitoring tools is highly desirable for the sensitive detection of organophosphate pesticide (OP) residues in water and agriculture products without interference. A novel disposable acetylcholinesterase (AChE) biosensor with low detecting potential (+50 mV), good selectivity, and high sensitivity was developed based on electrochemically reduced graphene oxide and Nafion hybrid nanocomposite (Er-GRO-Nafion) modified electrode. The Er-GRO-Nafion nanocomposite with conductive and three-dimensional interpenetrating network owns excellent characters as electrode modification material. It effectively promoted the electron transfer rate of electrode interface, could catalyze the anodic oxidation of thiocholine at ultra-low potential, and facilitated the access of substrates to the active centers. The modified electrode was used for the electrochemical detection of dichlorvos after adsorbing AChE on the biocompatible matrix. By dexterously controlling the electrochemical reduction variables and optimizing the electrode preparation parameters, the proposed electrochemical biosensor showed high sensitivity, wide linear range (from 5.0 to 100 ng mL(-1) and from 1.0 to 20 mu g mL(-1)), low detection limit (2.0 ng mL(-1)), good stability and reproducibility. It also had high precision for the real sample analysis, which indicated the good perspective for field application. (c) 2012 Elsevier B.V. All rights reserved.