Analysis Of Benzoylurea Insecticides And Preservatives In Foods By High Performance Liquid Chromatography

Food is the basic material for human to survive and development. In recent years, theproblem of food safety has been paid close attention to by the public in China. Pesticideresidues and food additives are two important aspects, so it is important to monitor pesticideresidues and additives in food. In the first chapter, we summarized the characteristics andhazard of benzoylurea insecticides and dimethyl fumarate, and introduced the main analysismethods to them. In the second chapter, new method based on enrichment of microextractionflask-liquid chromatography was used for determination of benzoylurea insecticides in waterand apple vinegar. Factors relevant to the extraction efficiency, such as extractant, saltinity,extactant volume and extraction time, were studied and optimized. For triflumuron,hexaflumuron and teflubenzuron, the linearity was good in the range of0.5-100μg/mL withthe correlation coefficients above0.9998. In water and apple vinegar, the recoveries were89.77%-102.18%and73.50%-102.69%, respectively; the relative standard deviations (RSDs)were less than5.7%and5.4%, respectively; the detection limit was1.0ng/mL and5.0ng/mL,respectively. In the third chapter, a method for determination of diflubenzuron andteflubenzuron in pear juice drink by salting out phase separation solid phase extraction-highperformance liquid chromatography was developed. The sample was extracted withacetonitrile and cleaned up by the solid phase extraction using florisil. Benzoylureainsecticides were separated on C18column employing methanol: water=85:15as mobile phaseand determined using UV detector at260nm. For diflubenzuron and teflubenzuron, themethodology exhibited good linearity between0.5to100μg/mL. The recoveries were75.11%and83.16%, respectively; RSDs were less than1.74%; the detection limits were0.0086μg/mL and0.0136μg/mL, respectively. In the fourth chapter, solid phase dispersionextraction-liquid chromatography was used for the determination of dimethyl fumarate inbean paste. The linear range was0.136-33.5μg/mL with correlation coefficient of0.9998. Thedetection limit was0.82μg/g and the recovery was82.5%.