| The wide use of organphosphorus pesticides has led to a series of problems such as severe environmental pollution and the threat of human health. Therefore, how to detect the Organphosphorus pesticides fast and effectively has a very important signification. Current analytical techniques such as chromatography, mass spectrometry and spectroscopy are sensitive and reliable, but are time consuming, costly, professional performance and can't be carried out in field scene. Biosensor technique can satisfy the requirement of rapid detection of organphosphorus pesticides online which overcomes the above-mentioned difficulties. At the same time, biosensors have the advantages of rapid detection, simplicity, high sensitivity and low cost. Therefore, biosensor technique has an excellent foreground and has been attentioned by a variety of fields recently. In this paper, we designed two kinds of multienzyme organphosphorus pesticides biosensors with simplicity, high sensitivity, good selectivity and convenience. The major contents in this thesis are described as follows:1. The development of the sensors modified by HRP and the detection of H2O2The rapid and sensitive detection of H2O2 is the important foundation of our organphosphorus pesticides biosensors. In this experiment, there are two sections about the detection of H2O2. The first section is the detection of H2O2 by the graphite electrode modified by HRP. Using the graphite electrode modified POPD as the basic electrode, the HRP was immobilized on it by means of Nano-Au adsorption. The results showed that the detection limit of HRP/Nano-Au /POPD/graphite electrode to H2O2 was 8.82×10-8 mol/L, the detection range was 3.53×10-7~2.15×10-2 mol/L. Moreover, the biosensor exhibited fast response, high sensitivity, good repeatability and long-time stability. The biosensor was applied in the determination of recoveries to real samples with satisfactory results. It can be used for development of the organphosphorus pesticides biosensor.Secondly, we used planar gold electrode modified by HRP to detect H2O2. The planar gold electrode was chosen as the basic electrode and was immersed in 4-MBA solution for self assembly through the Au-S covalent bond, then the–COOH of the electrode surface was activated by EDC and NHS so that the HRP was immobilized on the basic electrode. It was found that the detection limit of HRP/EDC+NHS /4-MBA/gold electrode to H2O2 was 8.82×10-9 mol/L, the detection range was 3.53×10-8~8.82×10-6 mol/L. It can detect H2O2 rapidly with the advantages of simplicity, high sensitivity, good selectivity and convenience. The biosensor can also be used for development of the organphosphorus pesticides biosensor.2. The detection of organphosphorus pesticides based on the inhibition of ALP by the bi-enzyme biosensorA potentiometric organphosphorus pesticides bi-enzyme biosensor has been developed based on the inhibition of ALP by organophosphorus pesticides, and it was applied in the determination of parathion and omethoate in solution. It was found that the potential value was proportional to the parathion concentration in the range of 8.58×10-6~2.24×10-3 mol/L with a linear regression equation y= -26.418x+58.225,R2=0.9962, and the detection limit 4.29×10-6 mol/L. Likewise, the linear regression equation of omethoate was y= -23.12x+54.742 with the detection limit 9.38×10-7 mol/L. In addition, the biosensor possesses of advantages of easy preparation, fast detection, good consistency and long lifetime.3. The detection of organphosphorus pesticides based on the inhibition of AChE by the multienzyme biosensorA potentiometric organphosphorus pesticide multienzyme biosensor has been developed based on the inhibition of AChE by organophosphorus pesticides, and it was applied in the determination of methamidophos in solution. The inhibition percentage was proportional to the methamidophos concentration in the range of 6.92×10-8~1.04×10-6 mol/L with a linear regression equation y=79.403x+10.925,R2=0.9972, and the detection limit 3.46×10-8 mol/L. The biosensor exhibits easy preparation, fast detection and high sensitivity.
|
PDF Full Text Request