| The problem that pesticide residues exceed maximum residue limits(MRLs)is not only harmful to the health of people,but also severely restricts the international trade of medicine in our country.Therefore,to establish a rapid,efficient,accurate and sensitive detection method of pesticide multiresidues may be helpful to guarantee people’s safety.It is an urgent problem to be solved in the process of promoting the international trade of traditional Chinese medicine.Objective:(1)To perform the screening of pesticide,and determine the LC-MS/MS analysis condition of target compounds,which is not less than 150.(2)To establish an universal modular sample pretreatment method,which can be used for the determination of pesticide multiresidues in different matrix types of traditional Chinese medicine.(3)To establish a LC-MS/MS analysis method for the determination of pesticide multiresidues in traditional Chinese medicine,and select representative samples of different matrix types of traditional Chinese medicine,to conduct the method validation of the LC-MS/MS analysis method for the determination of pesticide multiresidues.Complete the actual sample determination for pesticide residues,and then analyze and evaluate the results.Methods:(1)By the screening of pesticides varieties and the optimization of pesticide mass spectrometry parameters,chromatographic conditions and the ion source conditions,we determined the LC-MS/MS analysis condition for the pesticide multiresidues.(2)In the comprehensive consideration of the characteristics of traditional Chinese medicine and commonly used sample pretreatment methods,we mainly made study from the two aspects of extraction and purification systematically,to build a modular sample pretreatment method.(3)We selected Fritillary thunberg bulb,Ganoderma,Chrysanthemi flos and Coicis semen,4 kinds of different matrix types of traditional Chinese medicine,to complete our method validation,and determination of pesticide residues.Results:(1)We finished the screening of pesticides,and determined the LC-MS/MS analysis condition,with the detection target as many as 258.The mobile phase is methanol(0.1%formic acid and 5 mmol ammonium acetate solution)and water(0.1%formic acid and 5 mmol ammonium acetate solution)with the gradient elution mode.The column is Agilent Poroshell 120 EC-C18,3.0mm×150mm,2.7μm.The flow rate is 0.4 mL·min-1 and column temperature is 40℃.The ion source is ESI and scanning mode is positive and negative ion switching.The nebulizing gas is nitrogen with a flow rate of 3L·min-1.The heating gas is air with a flow rate of 10L·min-1.The interface temperature,DL temperature and heat block temperature is 300,200,400,respectively.The drying gas is nitrogen with a flow rate of 8L·min-1.The MS detection mode is MRM,which greatly reduces the interference factors and can effectively avoid the occurrence of false positive and false negative.This method has high sensitivity and good specificity.(2)We established a modular sample pretreatment method.It can be used for the determination of pesticide multiresidues in different matrix type of traditional Chinese medicine.There are four extraction methods that can be selected,which are homogenate extraction,oscillation method,ultrasonic extraction and accelerated solvent etraction.The extraction solvent is acetonitrile-toluene(3:1)solution containing 1%acetic acid as the extraction solvent.The purification method is divided into three modules,respectively as QuEChERS,solid phase extraction(using GCB/NH2 column)and gel permeation chromatography.When doing actual analysis,we can select an appropriate sample pretreatment method,according to the different matix types of traditional Chinese medicine.(3)We established a LC-MS/MS analysis method for pesticide multiresidues in traditional Chinese medicine,and completed the method validation in 4 different matrix types of traditional Chinese medicines,such as Fritillary thunberg bulb,Ganoderma,Chrysanthemi flos and Coicis semen.The average recovery rates are 60.8～129.5%,60.8～115.9%,60.3～125.9%at three addition level of 10μg·kg-1、50μg·kg-1、100μg·kg-1 in Fritillary thunberg bulb,and the RSD is 0.9～19.3%、0.8～17.8%、0.7～19.4%,respectively.The method detection limit of the method is 0.00000-0.21733mg·kg-1,and the method quantitation limit is in the range of 0.00000～0.65856mg·kg-1;The average recovery rates were 60.5～119.9%、60.5～121.6%、60.5～133.7%at three addition level of 20 μg·kg-1、100 μg·kg-1、200 μg·kg-1 in Ganoderma,and the RSDs were 0.4～15.3%、0.1～9.1%、0.3～17.0%,respectively.The method detection limit of the method is in the range of 0.00000-0.07096mg·kg-1,and the method quantitation limit is in the range of 0.00000～0.21500mg·kg-1;The average recovery rates are 62.0～139.1%、61.4～137.3%、60.4～132.8%atthree addition level of 40 μg·kg-1、100 μg·kg-1、200 μg·kg-1 in Chrysanthemi flos,and the RSD is 0.3～16.9%、0.3～15.1%、0.3～14.5%,respectively.The methood detection limit of the method is in the range of 0.00002～0.35834 mg·kg-1,and the method quantitaton limit is in the range of 0.00006～1.11616 mg·kg-1;The average recovery rates are 61.7～128.4%、62.0～130.6%、61.2～124.6%at three addition level of 20 μg·kg-1、40 μg·kg-1、100 μg·kg-1 in Coicis semen,and the RSD is 0.1～16.0%,0.2～15.3%、0.0～19.2%,respectively.The method detection limit of the method is in the range of 0.00003～0.27350 mg·kg-1,and the method quantitaton limit is in the range of 0.00005～0.82878 mg·kg-1.The number of pesticides that meets the requirements of pesticide multiresidue analysis in the test of validation is all more than 200 for this four different matrix types of traditional Chinese medicine.It can be used as a universe method.We determined the amount of pestiside residues in a total of 143 batches of Fritillary thunberg bulb,Ganoderma and Chrysanthemi flos.In the result,the phenomenon of excessive pesticide residues exists in both Ganoderma and Chrysanthemi flos.Above all,pesticide residues should be paid sufficient attention by our society.Conclusion:(1)We determined a LC-MS/MS analysis method that can be used to simultaneously determine 258 kinds of pesticide compounds.This method can also be used for rapid screening and quantitative analysis of pesticide residues.It can also be used in food,agriculture,environment and other areas of the detection of pesticide multiresidues.(2)We established a modular sample pretreatment method.It can be used for the determination of pesticide residues in different matrix types of traditional Chinese medicine.When doing actual analysis,we can choose an appropriate sample pretreatment method,according tothe different matix types of traditional Chinese medicine.(3)The number of pesticides that accord with the requirements of pesticide multi-residue analysis in the test of validation is all more than 200 for this four different matrix types of traditional Chinese medicine.It can be used as a universe method.The determination result of pesticide residues shows that the phenomenon of excessive pesticide residue is a serious problem in traditional Chinese medicine.The method we established to determine the pesticide multiresidues may provide effective and feasible analysis technique for the Quality and safety control of traditional Chinese medicine.It will provide technical support for the supervision and control of traditional Chinese medicine,and promote the harmful residual safety technical standard system of traditional Chinese medicine in line with international standards. |
PDF Full Text Request