| Organphosphorus pesticides are widely used in the prevention of crop disease and bug weeds for production increase, as they have advantages of rapid,wide adaptability and stability. However unique chemical properties make pesticide not easy to degrade in nature, food safety and environment pollution problems caused by pesticide residues are more and more seriously, pose a serious threat to the environment and human health. At present traditional analytical methods for pesticide residues (such as gas chromatorgraphy, liquid chromatorgraphy and mass spectroscopy) require expensive equipment, trival and professional operation, and are not applicable for on-site determination. Therefore, the research of method which can rapidly and sensitively detect pesticide residues is of important significance. Organphosphorus pesticides biosensors not only have the characteristics of high sensitivity, good selectivity, also have low material cost, simple manufacture process, strong anti-interference ability, suitable for rapid detection of pesticide residues, it is a hot topic in the area of pesticide residues analysis now.In this thesis, a potentiometric H2O2 sensor is developed based on immobilizing HRP on the surface of MCPE by using Au@PBMNPs and Au@Fe3O4MNPs, and collaborative catalysis in Au@PBMNPs, Au@Fe3O4MNPs and HRP play a great role in the development of the sensor. And then detect the H2O2 producted in the hydrolysis reaction of 3-IP catalytic by ALP, according to the inhibition to ALP by organophosphorus pesticide, we can realize the trace analysis of organophosphorus pesticide. Results show that the method for organophosphorus pesticide detection is simple and rapid, have low detection limit, high sensitivity, and has certain application prospect in organophosphorus pesticide detection.In this thesis the major contents include three sections as follows:(1) Study on the potential response property of carbon paste electrodes to H2O2 in reacting system of O-phenylemediamineA novel system for determining H2O2 by potentiometry method is established based on the reaction between H2O2 and O-phenylenediamine(OPD) with the product of 2,3-Phenazinediamine(DAP), and the potential response property of carbon paste electrodes(CPEs) to H2O2 are investigated. Under optimum experimental conditions, CPEs show the linear response range to H2O2 from 3.53×10-6 to 6.38×10-2 mol/L and the detection limit is 1.91×10-6mol/L, the slope of working curve is 23.42mV/decade. The results indicate that in the system which is designed, CPEs have low detection limit, high sensitivity, wide linear range, excellent electrode consistency and reproducibility. Compared with general electrochemical enzyme sensors, CPEs have simple preparation method, stable property, lowcost of raw materials which are easy to obtain, and also have better application prospect.(2) Development of a novel potentiometric H2O2 sensor based on Au@PBMNPs, Au@Fe3O4MNPs and HRPIn order to detect organophosphorus pesticide rapidly, we should development of a novel potentiometric H2O2 sensor to the rapid detection of H2O2. PBMNPs and Fe3O4MNPs is coated by nano Au, then Au@PBMNPs and Au@Fe3O4MNPs which have more stablility can be immobilized on the surface of MCPE by static adsorption force and magnetic, a sensor for rapid and trace detection of H2O2 is developed based on collaborative catalysis in Au@PBMNPs, Au@Fe3O4MNPs and HRP. Results show that the H2O2 sensor shows excellent catalytic response to the reduction of H2O2 and has short response time(less then 2s), the linear response range from 8.82×10-8 mol/L to 3.53×10-3mol/L which has spanning 6 orders of magnitude and the detection limit is 8.71×10-8 mol/L. The sensor has advantages that of rapid response, low detection limit and broad linear range which can be used in the rapid and trace detection of organophosphorus pesticides.(3) Application of HRP/Au@Fe3O4/Au@PB/MCPE uesd in the rapid detection organophosphorus pesticide.H2O2 producted in the hydrolysis reaction of 3-IP catalytic by ALP is detected, based on the inhibition to ALP by organophosphorus pesticide, parathion and omethoate in solution are detected, the linear response range are 8.58×10-6mol/L to 1.56×10"3mol/L and 1.88×10-6mol/L to 1.50×10-3mol/L, and the detection limits are 10-6 mol/L. This method realizes the rapid and trace detection of organophosphate pesticides, has a broad application prospect. |
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