| It is well known that governments and organizations around the world have attached great importance to the pollution hazard because of the extensive use of pesticides, and many policies and regulations about the using of pesticides were enacted, for example it is prohibited to use pesticides of high pollution. Meantime, environmental and food safety issues caused by pesticide residues become increasingly serious, which will affect the safety of human life. Therefore, it is inevitable trend to develop new pesticide residue detection method combining with modern science and technology.Moreover, a variety of effective techniques for the degradation of pesticide residues are used, which is also an important research field to reduce environmental pesticide residues and pesticide toxicity.This work has been carried out under the above-mentioned background and carries out to a series studies on the basis of laboratory. This paper mainly studies the pesticide residues in fruit juice by spectroscopic technology, and the quantitative analysis mathematical models are established about pesticide residues based on spectrum technology. The reasearch of pesticide degradation technical about the detected pesticide will be carried out on the basis of the above work, including ozone,ultraviolet, and Chinese herbal of medicine and food homology. And interaction information systems between pesticides and bio-molecular will be constructed under the help of various spectral analysis method, which can provide technical support for studying the toxicity changes of pesticide before and after degradation. This project is the systematic study about the detection and degradation of pesticide residues, the interactions between pesticides and bio-molecular. And there are important economic and social value ensuring the food safety, degrading pesticide pollution and understanding the functional mechanism of pesticide.The main innovations and research contents of this thesis are as follows:(1) Ii is put forward to detect pesticide residues in pure fruit juice based on the UV-visible absorption and fluorescence spectrum, and the relationships between spectral peak intensity and drug concentration were studied about pesticide(Imidacloprid, Carbendazim, Abamectin and Chlorothalonil)and the mixed solution with pure juice(apple juice, orange juice an peach juice). The prediction models of pesticide residues in pure juices were obtained according to the experimental results through the regression analysis, and the correlation coefficients are basically over 0.99. Meantime the model function was evaluated and analyzed including these aspects of recovery rate, detection limit and the limit of quantification, etc. The analysis results show that the Savitzky-Golay spectrum smoothing can improve the correlation coefficient according to carbendazim-juice mixed system absorption spectra. It is also proved that derivative spectra can improve the resolution of the model function through avermectin-peach juice mixed system absorption spectra, and the detection limit and the limit of quantification have been increased nearly 5 times. In summary, it is feasible to meet the needs of fast and accurate analysis of pesticide residues using the UV-visible absorption andfluorescence spectrum.(2) The hardware platforms about pesticide residue degradation are designed and built based on ozone and ultraviolet light technology. It is put forward to describe degradation effect according to the change of pesticides absorbance, and the prediction models of pesticide residues degradation were obtained according to the relationship between degradation time and absorbance.Combining with the pesticide residue detection model function based on the absorption spectrum, the degradation rate is calculated corresponding to different degradation time. According to the ultraviolet light degradation experiment results about the mixed system between pesticide(Imidacloprid, Abamectin and Hymexazol) and pure juice(apple and peach juice), it is shown that degradation effect of Imidacloprid is best, and the degradation rate is about 3 times of Avermectin and Hymexazol. According to the ozone degradation experiment results about the Imidacloprid, Abamectin and Chlorothalonil, it is shown that degradation effect of Abamectin is best and the degradation model can be constructed,while we can not achieve the accurate degradation model about Imidacloprid and Chlorothalonil. As an exploratory research, it is explained to realize the pesticide degradation using Chinese herbal of medicine and food homology through the change of fluorescence peak intensity.(3) The binding mechanism of pesticides(Carbendazim and Hymexazol) and bovine serum albumin(BSA) was studied by fluorescence, UV-vis spectroscopy and synchronous fluorescence. The pesticide-serum albumin interaction information systems are constructed including binding constants,the number of binding sites, binding distance, fluorescence quenching type, the interaction force type and the conformational changes of BSA. It is put forward to study the toxicity changes of pesticide before and after degradation using UV radiation and ozone according to the information systems. The results show that: ozone degradation will result in the change of quenching type about Hymexazol(from static quenching to dynamic quenching); UV and ozone degradation can change the binding constant between the two pesticides and BSA, and will change the interaction force type between the Carbendazim and BSA(from electrostatic force to Hydrogen bonds and van der Waals forces); UV degradation will result in the decrease of binding distance, while ozone degradation will result in the increase of binding distance between Hymexazol and BSA; Carbendazim and Hymexazol after UV and ozone degradation will affect the BSA conformation, which is proved because of the blue shift of their synchronous fluorescence spectra(Δλ = 60nm). Research results can provide the reference to observe pesticide degradation and toxicity variation at the molecular level. |
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