Determination Of Pesticide Residues In Tea By Gas Chromatography-mass Spectrometry

Tea is a traditional Chinese drink.From China to the world,it is not only an important cash crop in China,but also one of the main export agricultural products in China.It occupies a huge share of the world beverage market.The city in the south of the Yangtze River is the largest production city in the province,and the production of tea is in the forefront of the country.With the improvement of the people’s living standard,the quality and safety of tea are becoming more and more concerned.With the increase of tea production and the emergence of new pesticides,there are more and more pesticide residues in tea.A rapid and effective method for the detection of pesticide residues in tea is studied in view of the possibility that there may be more pesticides in tea.Objective:A gas chromatography-mass spectrometry method for the detection of pesticide residues in tea leaves is established.The new method was applied to detect pesticide residues in tea,and completed the national food safety risk monitoring task.It provided data support for national formulation and adjustment of pesticide residue limit standard(MRL).A new method was established to detect pesticide residues in real estate tea in Yixing,and to understand the status of pesticide residues in real estate tea in Yixing,so as to provide scientific basis for relevant departments to formulate pesticide supervision and control measures.The establishment of testing methods is of great significance to the protection of human health,the reduction of agricultural losses and the reduction of international trade disputes.Methods and contents:1.13 target compounds were determined by consulting the literature at home and abroad.2.By comparing the solid phase extraction method and QuEChERS method of different pretreatment methods,And compared with electron ionization source mass spectrometry and negative chemical ionization source mass spectrometry,selection of pretreatment and detection method for the target compounds,the eventual establishment of pesticide separation,sensitive,accurate and rapid multiresidue detection technology.3.The pesticide residues in Yixing’s real estate tea were detected by the established analysis method,and the status of the 13 Pesticide Residues in the real estate tea in our city was preliminarily understood.The results were analyzed,and the Countermeasures for prevention and control were discussed.Result:A method for the determination of 13 Pesticide Residues in tea by gas chromatography mass spectrometry was established through experiments.The method uses three pole quadrupole detection technology,data acquisition and mass spectrometry multi response monitoring(MRM)scanning mode,sample pretreatment using solid phase extraction and QuEChERS two methods.When applied,it can be selected according to laboratory hardware conditions and testing purposes.Conclusion:1.The new method established in this study not only can detect 3 new pesticides,including Indoxacarb,Acetamiprid,Chlorfenapyr,but also detect Dicofol,Fenvalerate and other pesticides on tea plant.It can also detect more widely used pyrethroid pesticides in tea plants.The method has the advantages of simple operation,low requirement for equipment,high sensitivity,strong anti-interference ability and good reproducibility,so it is suitable for popularization and application.2.QuEChERS method was used to extract and purify tea samples.The method of detection established in this study was applied to analyze 74 samples of real estate tea collected,and the pesticide residue status of Yixing real estate tea was investigated.The results showed that the qualified rate of 13 kinds of pesticide residues in Yixing real estate tea was 100%.There is no significant difference in the detection rate of pesticide residues in different varieties of tea and different planting areas.The new pesticides with high efficiency and low toxicity are widely applied in tea planting.No restricted pesticides were detected in all samples.