| Special agricultural product refers to the special or famous product of a certain place with which there is cultural connotation or history,and also refer to a kind of product only produced in a certain place.In recent years,people pay more and more attention to food nutrition and health.The demand for special agricultural products is also increasing.In order to improve the yield,pesticides are widely used in cultivation and production process of agricultural products.However,due to the irregular usage or misusage,pesticide residues are often detected or exceed the MRL.Some countries or organizations,such as China,Japan and European Union etc.,have formulated more and more regulation items related to MRLs for different agricultural products.Due to the matrix complication,target substances population and polarity range,new requirements and challenges are proposed for the detection methods of pesticide residues.Pretreatment is a key step in the extraction of target substances from complex agricultural substrates,especially when the concentration of target substances in some samples is low.It is particularly important to establish an efficient,rapid,simple and environmentally friendly pretreatment method in sample analysis to achieve good separation,purification and enrichment of target pesticides.Chromatography-mass spectrometry is the main method of multi-pesticide residues analysis.High-resolution mass spectrometry(HRMS)based on accurate qualitative confirmation,with high sensitivity and full scan mass spectrometry,which can be potentially applied in the high-throughput screening of multi-pesticide residues.In chapter 1 of this paper,the research progress of sample pretreatment technology is briefly introduced,and the detection technology of pesticide compounds is concisely summarized.In chapter 2,A method that efficient enrichment and analysis of atrazine and its degradation products in Chinese Yam using accelerated solvent extraction and pipette tip solid-phase extraction followed by UPLC–DAD was developed.Molecularly imprinted polymer(MIP)was used as the adsorbent material.Experimental performance was investigated that the limit of quantification was 1–3?g/kg,and recoveries range was 79.2–103.8%.Compared with previous reports,this method could provide superior performance of sensitivity.This method is,therefore,expected to be useful in supervised residue analysis.In chapter 3,a method of rapid solvent extraction combined with high performance liquid phase triple quadrupole mass spectrometry was developed for the determination of Neonicotinoids pesticides in pollen.The method can effectively and rapidly separate and analyze Neonicotinoids pesticides in pollen samples.Green solvent(water)was used in accelerated solvent extraction(ASE),which could greatly improve the applicability of the method due to its environmentally friendly.The conditions of separation and detection were investigated and optimized.The recoveries at three spiked concentrations levels for Neonicotinoids pesticides in pollen samples were in the range of 83.3–100.6%with RSDs?4.4%.The method LOQ was 0.25–5?g/kg.The proposed method was applied for the determination of Neonicotinoids pesticides in actual pollen samples successfully,which is fast,environmentally friend and high sensitive.In chapter 4,a method of SPE-LC-Q-TOF/MS was established for rapid screening and identification of 377 pesticide residues in Goji(Lycium barbarum).Combined with the laboratory-built PCDL database,a fast screening method was proposed by using All Ions MS/MS,which does not need the standard reference materials,and only one sample injection could complete the first level accurate quality screening and high-resolution secondary fragment ion full scan mass spectrometry confirmation.LC-Q-TOF/MS provides better method selectivity,accuracy and precision in All Ions MS/MS acquisition mode.The results showed that the method was cost-saving and sensitive,which improved the efficiency of pesticide residue screening,and could provide a reference for the rapid screening of multiple pesticide residues in Chinese medicinal materials.In chapter 5,a high throughput screening and quantification method for 481 pesticide chemical contaminants in tea was established based on automatic solid phase extraction-LC-HRMS.In this study,an automatic SPE system based on TPT purification column was established,which not only improved the throughput but also reduced the cost and time.In the experiment,the sample preparation process,the type and volume of extraction solvent,the volume of water and the extraction column were optimized,and the qualitative and quantitative methods were verified and evaluated,this method is applied in the analysis of the actual samples.Compared with the previous analytical methods,this new method has the advantages of high throughput,high sensitivity,good repeatability,high standardization and high pass rate.Therefore,this study can provide important technical support for the rapid screening and accuracy quantitation of multiple pesticides in tea.In chapter 6,a high throughput screening and quantification method for 488 pesticide chemical contaminants in almond by solid phase extraction-liquid chromatography-time-of-flight mass spectrometry was established.Carb-NH2 column could effectively reduce matrix interference,and moderate or weak matrix effect(ME)was shown in 95.0%pesticides.The limit of screening(SDL)of 87.9%pesticides and the limit of quantification(LOQ)of 83.6%pesticides were less than or equal to 10?g/kg,which indicate this method have the high screening and quantitative ability.This method provides technical support for the detection of multiple-pesticide residues in almond samples,and can provide reference for the high-throughput screening of multi-pesticide residues in other nut matrix.This study timely responded to the main problems of food safety and trade in the current specialty agricultural products pesticide residues,and provided strong technical support for food safety risk monitoring.The established method is sensitive,rapid,high-throughput,accurate and reliable,which is suitable for the qualitative,quantitative and confirmatory detection of pesticide residues in specialty edible agricultural products.This research has certain practical application value. |
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