| The quality and safety of food is crucial to human's life.However, the presence of pesticide residue in food has become one of the serious problems that has greatly attracted government and organization's concerns. As the maximum residue levels of pesticides adopted by the legislation in the world become more and more strict, it is very important to develop simple, fast and efficient analytical methods.This dissertation focused on the studies of analytical methods on pesticide residue of organochlorine, organophosphorous and pyrethroid. After optimizing the analytical conditions of gas chromatography mass spectrometry (GC-MS) and gas chromatography tandem mass spectrometry (GC-MS/MS), the method for the residue determination of pesticides in food has been established. The dissertation consisted of four chapters.In the first chapter, the development history and toxicology theory of organochlorine, organophosphorus, carbarmate and pyrethroid pesticides were simply introduced. Current progress of multiclass pesticide residue analysis in food was summarized with emphasis on various detection methods for pesticide residue. Finally, the idea and plan of this dissertation as well as the aim and content of the research work was also dissussed.In the second chapter, GC-NCI/MS was applied to the simultaneous determination of 19 organophosphorus pesticides in milk and milk power. After optimazing the pretreatment conditions, pesticides were extracted from milk drink or milk powder with acetonitrile in an ultrasonic bath and cleaned up on a Florisil and neutral alumina column, then were determined by gas chromatography with negative chemical ionization mass spectrometric detection in the selected ion monitoring mode. Besides, the recoveries, limit of detection, accuary, precision and linear range of the method were investigated in detail to pledge the quality.In the third chapter, method of GC-MS/MS was studied. Take 13 organophosphorus pesticides for example, several parameters for MS/MS such as ionization mode, scan time, parent ion, excitation storage level, CID voltage, quantitation ions, trap temperature and so on were optimized. Electron impact ionization (EI) and chemical ionization (CI) were employed in a single analysis for the determination of pesticides according to the differernt sensitivity of each pesticide. Besides, method of GC-MS/MS for organochlorine and pyrethroid pesticide residue was also optimized. Multi-reaction monitor provided by Saturn 2100T GC-MS/MS system were applied to supply several channels to separate compounds in shorter time.In chapter four, take milk for matrix, traditional matrix solid phase dispersion (MSPD) was improved. After the effect to the analysis results of several parameters were studied, the optimized pretreatment method along with GC-CI(EI)-MS/MS were applied to the analysis of 13 organophosphorus pesticides in milk. Besides, the recoveries, limit of detection, accuary, precision, selectivity and linear range of the method were investigated in detail to pledge the quality of the method of GC-CI (EI)-MS/MS.
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