| The pesticide residues are the critical food safety question concerned by every nation, relative to persons' healthy and international trade in food. So the maximum residue levels (MRL) in food were constituted by WHO/FAO-CAC. Some developed county created difficulties for our foreign trade by the detection technologies of pesticide residues in food, therefore it is the critical problem in executing the law about food safety and international trade. In order to protect consumers' healthy, avoid handicapping by the developed country in international trade, improve the competitive ability of our food in the international market, it is very important to exploit the prompt detection technologies based on pesticide residues in food and the requirement for international trade on food. It is the trend to exploit simply, fast, efficient pre-treatment technologies for samples and high sensitive, high selective methods in multi-pesticide residues detections. Focused on the study on micro-chemical method and solid-phase extraction technology used in the sample pre-treatment and the detection methods by gas chromatography, fast methods on the multi-pesticide residues in food has been established. The methods are significant for the management on food safety and international trade.The thesis includes three parts: the background and literature summarize (Chapter I), four Methods of determination for pesticide residues in food (Chapter II to V), and the primary study on analysis method on the Hope pesticide residues in food (Chapter VI).Sample pre-treatment technologies and their application to pesticide residues analysis were introduced in Chapter I. It is mainly in the micro-chemical technology and gas chromatography method.In Chapter II, the method of analysis on methamidophos in Allium Chinense has been established. And high recoveries (87.4-109%) have been obtained by changing the quantity of acetone in organic and water phase. Relative standard deviations (RSDs) were from 0.5% to 2.5% and the detection limit was 0.02 mg/kg, according with the requirement of MRLs.In Chapter III, It is method of determination for 13 OPPs with weak polarity in Allium Chinense. Multi-organophosphorus pesticides were extracted under 2 anddetected by gas chromatography. The interference of the chemical substance in Allium Chinense was eliminated. The recoveries were from 61.5% to 135%. RSDs were from 2.6% to 15% and the detection limits were from 0.005 mg/kg to 0.04 mg/kg, according with the requirement of MRLs on the organophosphorus pesticide residues in Allium Chinense.In Chapter IV, twenty organophosphorus pesticides in tea have been analyzed using gas chromatography. The most kinds of organophosphorus pesticides in tea can be detected with the same program in domestic. The recoveries were from 60% to 120%. RSDs were from 0.3% to 10.2% and the detection limits were 0.018-0.04 mg/kg, according with the requirement of MRLs by European Union (EU) on the analysis of organophosphorus pesticide residues in tea.In Chapter V, the method has been established for determination 8 Carbamate pesticide residues in tea using gas chromatography with micro-chemical and solid phase extraction technology based on the new pesticide residues regulated by EU and the practice in our tea gardens. The recoveries ranged from 70% to 104%. RSDs were 2.4%-8% and the detection limits were 0.01-0.1 mg/kg. This method is rapid, sensitive and suitable for pesticide residues analysis. It can also be applied to the determination of Carbamate pesticide multi- residues in other plant samples such as vegetables, fruits and so on.In Chapter VI, the analysis method for Hope in food using gas chromatography was primarily investigated. Hope pesticide residues in rice and Allium Chinense were detected using micro-chemical method and improved sample pre-treatment technology. The research results indicated that the standard pesticides added in blank samples can be derived quantitatively and can be detected with good linearity by gas chromatography. And this method can b... |
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