Preparation And Application Of Electrochemical Sensor Base On The Magnetic Nanoparticles

Organophosphorus pesticides?OP?,phenolic compounds and H₂O₂ will cause serious harm to human health and environment,detect these pollutants is an important subject in the area of food safety and environmental protection.The traditional methods are tedious and cost time.So it is necessary to establish a fast and sensitive method.Chemical sensors and biosensors are applying in the field of food and environment monitoring.First,the multi-wall carbon nanotube composite materials,Prussian blue-gold nanoparticles?PB-Au?were prepared to build H₂O₂ sensor for detecting OP in this paper.Then use Fe₃O₄ coate with Prussian blue?Fe₃O₄MNPs@PB?as a catalyst for removing H₂O₂ in water.Finally,the electrochemical sensor of phenol was studied by Fe₃O₄-MWCNTs.While,this paper achieves following results:1?The H₂O₂ sensor to detect the residue of organophosphorus pesticide based on composite materials,Prussian blue-gold nanoparticles.Use the method of crosslink to absorbe chitosan?CS?on the surface of multi-walled carbon nanotubes,applying the amino of CS to combine with gold nanoparticles?GNPs?that forming Au-NH₂,and then the gold nanoparticles-multiwalled carbon nanotubes-chitosan?GNPs-MWCNTs-CS?composites materials was prepared.A novel H₂O₂ sensor was prepared by GNPs-MWCNTs-CS together with PB-Au modified gold electrode.The H₂O₂ in the system of catalyze 3-IP by ALP was detected,trace parathion and folimate were analyzed based on the catalytic activity of ALP was drastically inhibited,the detection limit was 2.00×10^-66 mol/L.The results for detect parathion residues,omethoate residuewas in cabbage was399mg/kg and 99mg/kg,respectively.The recovery rate is in the range of 90⁹5%.2?The study of Fe₃O₄MNPs@PB as catalyst to degrade H₂O₂.Magnetic iron oxide nanoparticles?Fe₃O₄MNPs?is prepared by co-precipitation and mix with FeCl₃,K₄[Fe?CN?₆]solution,then the core-shell structure of Fe₃O₄ MNPs@PB was successfully synthesized.The Prussian blue?PB?has the activity of like-enzyme,it can decomposes H₂O₂,due to the Fe₃O₄ has the property of magnetic,Fe₃O₄MNPs@PB can be separated effectively from aqueous solution by an external magnetic field.In the reaction of Fe₃O₄MNPs@PB catalytic H₂O₂ decomposition,we have studied the experimental parameters of pH,temperature,reaction time,the ratio of concentration and the recycle time of Fe₃O₄MNPs@PB was pH6.5,55?,35 min,74:100 and it can recycle 4 times,respectively.3?The electrochemical sensor of phenol is studied base on Fe₃O₄MNPs-MWCNTs composite materials.Fe₃O₄MNPs-MWCNTs composite materials are prepared by co-precipitation,then put it on the surface of magnetic carbon paste electrode?MCPE?.Naturally dried at room temperature,the modified MCPE was prepared by the Fe₃O₄MNPs-MWCNTs.The electrochemical impedance spectroscopy?EIS?and cyclic voltammetry?CV?were used to characterize the modified electrode.The results show that:in the condition of pH6.5,[H₂O₂]was 0.02mM,and the reaction time was 15 min,the modified electrode behaves well.Series of phenol were detect by the prepared sensor.The results show that the phenol concentration have a good linear relationship with the peak current of DPV in the range of5.00×10^-9mol/L¹.00×10^-4mol/L,the correlation coefficient was 0.99,the detection limit was1.69×10^-9mol/L.Applying the prepared sensor into the detection of phenol samples,the results were accurate.So the modified electrode can be used in analyse of trace phenol.