The Study On Preparation And Detection Of Pesticides Of Amperometric Acetylcholinesterase Sensor Electrodes

With the continuous development of China's economy and improvement of living standards,the concept that we should eat full and be healthy has been more and more popular in recent years.Therefore,to develop a kind of electrochemical sensor which can be applied to rapidly and sensitively detect the pesticide residue has a great importance to ensure the food safety of our country.The study on preparation and detection of pesticides of amperometric acetylcholinesterase sensor electrodes mainly includes the following three parts:1)Prepared graphite electrode by using thick film technology,studied the effects of three kinds of adhesive electrodes,namely,HPMC,cellulose acetate and chitosan,on the performance of the prepared electrodes.The orthogonal test results proved that the chitosan with the concentration of2.5%is the best binder.2)Through the XRD test result showed that the reaction of nickel foam with potassium ferrocyanide solution generated a complex Ni₂Fe?CN?₆·0.5H₂O,which is insoluble in water.Therefore,foam nickel electrode is not suitable for using potassium ferrocyanide to test its electrochemical characterization.However,nickel foam has stable property in phosphate buffer containing acetylcholine chloride,the enzyme biosensor which is prepared by foam nickel/graphite electrode could be used for the detection of pesticide.Composite graphite electrode that is prepared through tablet method can be directly used to detect potassium ferrocyanide and hydroquinone detection solution,this electrode conducts well and responds sensitively.3)The AChE electrochemical biosensor is prepared by AChE and AChE is fixed by adsorption-covalent crosslinking method,the enzyme modified electrode is characterized using cyclic voltammetry method and electrochemical impedance method.The sensor mentioned above is used to detect pesticides including carbosulfan and dursban.The results show that the enzyme electrode biosensor reacted sensitive to the two kinds of pesticides,when the enzyme inhibition percentage and pesticide concentration are at the range of 1.0×10^-61.0×10^-88 mo-1/L,they have a good linear relationship.Meanwhile,the lowest limits of detection are 2.45×10^-11mo1/L and 1.82×10^-11 mo1/L.