The Application Of Chromatography-Mass Spectrometry Technique In The Analysis Of Pesticide Multi-Residues In Nuts

Pesticide residue is one of the important issues that affect food quality and safety .It has attracted the great concern of the world's governments and organizations and is a greatly concerned and important issue in international trade. Therefore, the development of accurate, rapid, sensitive and practical method for the analysis of pesticide residues is undoubtedly the basis of controling pesticide residues, guaranteeing food safety and ensuring food import and export. In this paper, Gas chromatography - tandem mass spectrometry was employed to detect 185 kinds of pesticides having MRL in nuts. The detcetion conditions were optimized and the established method was proved to be simple and accurate with low detection limit. This thesis is divided into two chapters:Chapter 1, Based on 124 papers, commonly used sample preparation and detection methods for the analysis of pesticide residues were reviewed. Among sample preparation methods, solid phase extraction, solid phase micro extraction, gel permeation chromatography, supercritical fluid extraction, matrix solid phase dispersion extraction, accelerated solvent extraction and microwave assisted extraction were discussed. Among detection methods, enzyme inhibition, immunoassay, biosensors and chromatography were introduced.Chapter 2, A method was developed for the determination of 185 pesticides in nuts(Peanuts, Sunflower seeds, Walnuts and Almonds )by gas chromatography tandem mass spectrometry (GC-MS/MS) .The sample was extracted by 1% acetic acid acetonitrile and cleaned up by C18 tandem PSA solid-phase extraction. Detection limits (S /N = 5) ranged from 0.02 to 526.4μg/kg, and 81% pesticides were found to be below 10μg/kg,and all LOQ(limit of quantification) of these 185 pesticides were less than the maximum residue limits (MRL).These 185 pesticides have shown a good linear relationship with correlation coefficients larger than 0.99 ranged from LOQ to 83 LOQ. The recoveries were determined at three spiked levels of 1 LOQ ,2 LOQ and 4 LOQ in four samples. The average recoveries of 86.0% pesticides were between 70% and 110%; 90.5% pesticides were between 60% and 120%.RSDs of 82.3% pesticides were less than 10%. The established method is accurate,sensitive and simple,and can be used for the routine analysis of pesticide residues in nuts .