Study On Determination Of The Pesticide Residues In Environmental Sample And Farm Products

In recent years, the pesticide residues in environment and food are concerned more and more, and the improvement in their analytical techniques are also regarded highly because the variety and amount of pesticides continue to increase. The development of fast, reliable, sensitive and practical analysis of pesticide residues is the basis of controlling pesticide residues, ensuring environmental and food safety and avoiding international trade disputes .This thesis took Pendimethalin and Chlorothalonil pesticide residues as the research objects, and liquid-phase microextraction and matrix solid-phase dispersion extraction technique were used in the procedure of sample preparation in environmental water and some agricultural products samples,rapid qualitative and quantitative analyses were carried out by external standard method–high performance liquid chromatography. This thesis mainly included two aspects:The methods for the determination of pendimethalin and chlorothalonil pesticide residues in water by liquid-phase microextraction coupled with high performance liquid chromatography were established. The effects of extraction solvent, solvent volume, extraction time, stirring rate, temperature and salinity of solution on the single drop liquid phase microextraction were investigated detaily. The detection limit, relative standard deviation for determination of pendimethalin and chlorothalonil were 0.04μg/L and 0.02μg/L, 2.5%～3.4% and 3.1%～6.1%, respectively. The recoveries of spiked pendimethalin and chlorothalonil in the water samples were 88.0%～99.8% and 98.2%～106%, respectively. The highest enrichment factors for pendimethalin and chlorothalonil from water were more than 400 and 200, respectively.The methods for determination of pendimethalin in vegetables and chlorothalonil in fruits by matrix solid-phase dispersion extraction technology coupled with high performance liquid chromatography have been developed. The average recoveries of pendimethalin in vegetables ranged from 84.5% to 92.3%, and relative standard deviations were between 2.4% and 5.3%, The limit of detection for pendimethalin was 10.7μg/kg. The average recoveries of chlorothalonil in fruits ranged from 86.3% to 95.1%, and the relative standard deviations were between 1.7%～3.2%. The limit of detection for chlorothalonil was13.0μg/kg.