An acetylcholinesterase biosensor based on ionic liquid functionalized graphene–gelatin-modified electrode for sensitive detection of pesticides

Ionic liquid functionalized graphene (IL-GR) was synthesized through epoxide ring-opening reaction. A highly sensitive acetylcholinesterase (AChE) biosensor based on IL-GR and Gelatin (Gel) modified glassy carbon electrode (GCE) has been successfully developed. IL-GR was homogeneously dispersed in Gel and dropped on the surface of GCE. Glutaraldehyde (GA) was used as cross-linker to immobilize the AChE on IL-GR–Gel modified GCE. The IL-GR–Gel nanocomposite with excellent conductivity and biocompatibility offered an extremely hydrophilic surface for AChE adhesion. It effectively promoted the electron transfer rate of electrode interface and facilitated the access of substrates to the active centers. The modified electrode was used for the electrochemical detection of carbaryl and monocrotophos after adsorbing AChE on the biocompatible matrix. Under optimum conditions, the biosensor detected carbaryl and monocrotophos ranging from 1.0 × 10−14 to 1.0 × 10−8 M and from 1.0 × 10−13 to 5.0 × 10−8 M. The detection limits for carbaryl and monocrotophos were 5.3 × 10−15 M and 4.6 × 10−14 M, respectively. The developed biosensor exhibited many advantages such as high sensitivity, acceptable stability and low cost, thus providing a promising tool for analysis of enzyme inhibitors.