Determination of Organophosphorus Pesticides Using a Biosensor Based on Acetylcholinesterase Immobilized by Au Nanoparticles/Sol-gel Composite Membrane

Based on the inhibition effects of organophosphorus pesticides on acetylcholinesterase(AChE), an amperomerometric biosensor was developed by immobilizing AChE on glassy carbon electrode with the composite film of Au nanoparticals and chitosan-silica hybrid sol-gel. Using acetylthiocholine chloride as the substrate, the electrochemical determination method for organophosphorus pesticide was established with monocrotophos as a representative model for sensitivity tests. The experimental conditions were optimized according to the current response. The response of biosensor fabricated was related linearly to the concentration of monocrotophos in the range of 0.5-12.0 mu g/mL with a detection limit of 0.02 mu g/mL. The developed biosensor exhibited good reproducibility and acceptable stability, providing a simple method for the analysis of organophosphorus pesticide.