| The extensive use of various pesticides for many years has resulted in excessive pesticide residues in some Chinese medicinal materials,which seriously affects the quality of Chinese medicinal materials and proprietary Chinese medicines for subsequent deep processing,endangers human health and hinders the development of Chinese medicinal materials industry.Therefore,it is necessary to establish a new efficient pre-treatment method and analysis and detection technology to control pesticide residues in Chinese medicinal materials at trace level.In this study,a solid-phase Extraction(SPE)and GC-MS/MS method is established for simultaneous determination of multiple pesticide residues in Cassia seeds,Lycium barbarum and Torreya grandis,and samples from different regions are analyzed to verify the applicability and accuracy of the method.The main results are as follows:(1)SPE method combined with GC-MS/MS technology is established to simultaneously detect 35 pesticide residues in three kinds of medicinal and food homology of Cassia seed,Lycium barbarum and Torreya grandis.The extraction and purification factors are investigated,and the optimal parameters of each factor are finally screened out:15mL1% acetonitrile + acetate(v/v 1:99)as the extraction solvent,0.2g salt package(magnesium sulfate +sodium chloride + sodium acetate),homogenization twice,1min each time,Florisil solid phase extraction column as the purification material.And a mixture of 10 mL n-hexane +acetone(v/v 9:1)is used as the eluent for the experiment.(2)According to the physical and chemical properties of 35 pesticides,the optimum instrument parameters are determined.The matrix effect of 35 pesticides in cassia seeds,Lycium barbarum and Torreya grandis is investigated.Most of the pesticides showed matrix enhancement effect.Matrix matching calibration curve is used to eliminate matrix effect,and internal standard method is added to calibrate.35 pesticides in Cassia seeds,Lycium barbarum and Torreya grandis are tested by optimized pretreatment and instrument detection methods.Under these conditions,the linear range of 35 pesticides are 0.05 ～0.5μg/mL,the linear correlation coefficients are all greater than 0.997.The limits of detection(S/N=3)and quantification(S/N=10)are 0.6～48.5μg/kg and 2.2～91.2 μg/kg.The recoveries of the three herbs are 86.1～102.8% with relative standard deviations(RSDS)of 1.1%～10.0%(n=6)and daytime deviations of 0.74%～9.54%(n=6)at 50μg/kg(low-level),100 μg/kg(medium level)and 200 μg/kg(high-level)concentrations.At 0h,2.5 h,7 h,15 h and 27 h,the method have good stability,indicating that the method have high accuracy、sensitivity and stability,could satisfy the analysis of various agricultural residues in seed Chinese medicinal materials.(3)The recoveries of 35 pesticides are found to be in the range of 78.0% ～ 110.8%.The results are basically consistent with the pharmacopoeia method,indicating that the method is accurate and feasible compared with the standard method.(4)A total of 91 batches of cassia seeds,Lycium barbarum and Torreya grandis are randomly purchased from supermarkets,pharmacies and markets in Zhejiang Province.The detection rate is 70%,and the range of pesticide residues is 0.2 ～ 353.6 μg/kg.The average risk of chronic dietary intake(%ADI)of pesticide residues detected in Cassia seeds,Lycium barbarum and Torreya grandis are 0.043%、0.0131% and0.004675%。The acute dietary risk(%ARfD)of pesticides detected in Cassia seeds and Lycium barbarum are 0.000078% ～ 0.004305%,0.000036%～0.00432%.And %ARfD of Torreya grandis is 0.004567%.The quality and safety of the three kinds of Chinese medicinal materials are evaluated.This method has a positive significance on daily detection and risk assessment of import and export of chinese medicinal materials. |
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