| With the rising of peoples'living standards, the question of food safety has attracted more and more attention. Due to large-scale use of pesticides, pesticide residues in food and environment have attracted extensive attention. Many countries have established residue monitoring system and MRLs of pesticides in food, so food export of our country are facing more and more technical barriers. The analysis of pesticide residues in food which harm human health and influence environment safety is one of the important research duties to chemical analysts. But it is great difficult to separate fastly and measure accurately, because of the complexity of the determination system and the ultratrace components. At present, development of the fast, effective, sensitive multi-residue detection methods for pesticides residues analysis is the focus of study in the world.According to the kinds of pesticides used and the limits for pesticide residues in vegetables, fruits, tea and traditional Chinese medicine samples, this paper studied extraction, purification of sample pretreatments and chromatography/mass spectrometry detection conditions of pesticide residues and also developed a rapid, accurate, sensitive, cheap analytical procedure to determine multi-pesticide residues in food. The details are as follows:1. A rapid detection QuEChERS/GC/MS method was developed, which could detect 30 pesticides in vegetables,fruits and tea. Pesticides were extracted from samples with acetonitrile and clean up by C18,PSA and GCB. The collected solution was analyzed by the GC/MS and quantified by internal standard method. The 30 pesticides were separated efficiently from impurity in high sensitivity and reproducibility. The limits of detection (LODs) ranged from 0.015μg/L to 6.5μg/L. The recoveries ranged from 70% to 114%, and the relative standard deviations (RSD) were 0.49%～10.38%(n=6). The sensitivity,accuracy and precision of the method all satisfy the requirement of pesticide residue analysis.2. A GC/MS/MS method was developed for the simultaneous determination of 40 pesticides residues in radix astragal. Samples were extracted and cleaned up by QuEChERS, then determined by a triple quadrupole mass spectrometer with select reaction monitoring (SRM). There were good linear relationships between the peak area and concentration in the linear ranges of 0.0025～1.0 mg/L for the 40 pesticides, the limits of detection (LODs) ranged from 0.10 ng/L to 42 ng/L (S/N=3). The recoveries of those pesticides were 74.9%-112.2%, and the relative standard deviations (RSD) were 2.024%-11.582% (n=6), those quantified by internal standard method. The sensitivity,accuracy and precision of the method all satisfy the requirement of pesticide residue analysis.3. A UPLC/MS/MS method was developed for the simultaneous determination of 43 pesticide residues in rhizoma gastrodiae. Samples were extracted and cleaned up by QuEChERS. The UPLC was performed on a Waters ACQUITY UPLC HSS T3 (50 mm×2.1 mm,1.8μm) column. Using 0.05% formic acid and acetonitrile as mobile phase, the flow rate is 0.3mL/min. The analyte were detected by ESI (+) under multiple reaction monitoring (MRM). There were good linear relationships between the peak area and concentration in the linear ranges for the 43 pesticides, the limits of detection (LODs) ranged from 2.5μg/L to 170 ng/L (S/N=3). The recoveries of those pesticides were 73.23%～121.5%, and the relative standard deviations (RSD) were 1.23%～11.99% (n=6), those quantified by internal standard method. The method is simple, sensitive and suitable for preliminary screening and corroboration the corroboration samples.All the methods above were applied to analysis the real samples.
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