| Cloud point extraction (CPE) is a new extraction technology in recent years, which has been successfully developed into an important method of extraction/enrichment and analysis of organic pollutants in the environment. CPE was based on solubilization phenomena and cloud point phenomenon of the surfactant solution, micelles generated by changing the physical and chemical conditions (such as solution pH, temperature or ionic strength, etc.), so that the distribution of hydrophobic substances into micellesby phase separation and enrichment of hydrophobic substances, concentration and separation. The technology has the advantage of economical, efficient, simple, non-polluting. In recent years, CPE associated with chromatography method for the separation and preconcentration of organic compounds, plant hormones and drugs. However, there were fewer reports on combination between CPE and enzyme inhibition spectrophotometry. A new method for the determination of trace organophosphorus pesticides in environmental samples were proposed in this paper. Firstly, trace organophosphorus pesticides in environmental samples were preconcentrated as CPE mentioned above; secondly, preconcentrated samples were detected by enzyme inhibition spectrophotometry simultaneously. Satisfaction results were obtained, such as high sensitivity, veracity, and low limits of detection (LOD).This present thesis consists of four parts as follow:1. Several common methods of preparation of organophosphorus pesticide residues and the progress of the application of cloud point extraction coupled with detector in organophosphorus pesticide residues were reviewed. Mainly instruments include:chromatography and spectrometer, etc. Organophosphorus pesticide residue detection methods mainly are spectrometry and chromatography, but enzyme inhibition spectrophotometry is more suitable for fast detection than chromatography, chromatography test it takes a long time.2. TritonX-114was used as surfactant, separation and enrichment of the PM sample, and the separation conditions (acidity, the extracting temperature, water bath time, etc.) was optimized and found the best conditions. Using of the inhibition of cholinesterase activity determine the residues of PM. The response for the optimized assay was linear in the range between1μg/L-1000μg/L. A successive calibration curve was performed and the results showed a linear correlation:y=0.0855x+0.1008, where y is degree of inhibition and x is the concentration of PM of natural logarithm with r2equal to0.9962. The lower limit of the linear range was0.99μg/L (S/N=3) PM.3. Using cloud point extraction method extract cholinesterase from the earthworm body, and then the SDS gel electrophoresis method detect the purity of the enzyme, the result is satisfactory. In the experiment, surfactant concentration (TritonX-114), the choice of the buffer, the temperature of water bath and the time optimization, were determined and the best purification conditions show that:0.9%(v/v) Triton X-114, pH4.1citric acid buffer solution, in the35℃water bath balance9min.4. Using classical Ellman spectrophotometry determinate cholinesterase activity, cloud point extraction technology to separation and enrichment of PM in water sample of environment. In the process of experiment, the substrate concentration, restrain time, color agent concentration and other conditions were determined and the optimization conditions were found out. The proposed method was applied to study PM analysis in real samples such as water samples in order to test its performance, the recoveries for water samples were found to be92.67%-103.15%. |
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