The Research Of Enzyme Biosensor Based On Porous Graphene For Detecting Pesticide Residues

Chemical pesticides are widely used to protect the crops from harmful insect.Among them,the most representative organophosphorus and carbamate pesticides are harmful to the health of human beings.Therefore,it is urgent to develop a rapid,sensitive,simple,and reliable method for detecting ultra-trace pesticide residues.AChE based electrochemical biosensors are particularly attractive due to their high sensitivity,simple operation,low cost and fast response.In this work,three porous carbon materials have been prepared as electrode support materials of biosensors,which are used for the detection of organophosphorus and carbamate pesticides.The research contents and results include:?1?Holey graphene oxide?HGO?has been synthesized by one step hydrothermal method and applied to construct a highly sensitive acetylcholinesterase?AChE?biosensor.It is proved that HGO can effectively immobilize AChE and accelerate electron transfer rate.Under optimum conditions,AChE/HGO/GCE can effectively detect paraoxon with linear range from 10 to 45 ng mL^-1 and the detection limit of 5 ng mL^-1.Moreover,the developed biosensor is used for detecting paraoxon in real samples of lettuce and cabbage and shows a satisfactory recovery.?2?An amperometric biosensor AChE/HG/GCE for detecting of carbamate pesticides had been successfully fabricated based on efficient immobilization AChE on holey graphene?HG?.HG has rich porous structure and good electrical conductivity,which contributes to improve the sensitivity of AChE/HG/GCE detected pesticide.Under optimum conditions,AChE/HG/GCE can effectively detect carbaryl with linear range from 60 to170 ng mL^-1 and the detection limit of 30 ng mL^-1.?3?Amino functionalized porous nitrogen-doped reduced graphene oxide?NH₂-PNRGO?has been synthesized by hydrothermal method.The material not only maintains the unique physical properties of porous graphene,but also the amino group contributes to immobilize acetylcholinesterase.The AChE/CHIT-NH₂-PNRGO/GCE can effectively detect carbofuran with linear range from 0.05 to 11 ng mL^-1 and the detection limit of 0.025 ng mL^-1.