Determination Of Pyrethroids In Animal Foods By Chromatography-tandem Mass Spectrometry

Pyrethroid pesticides are a kind of synthetic broad-spectrum insecticides.They are widely used in crop protection,animal health and environment due to their high efficiency,low toxicity and strong contact toxicity.However,the pesticides have a cumulative effect on mammals and aquatic organisms.At present,the samples for the detection of these pesticides are mostly concentrated in fruits and vegetables,tea and water,and the commonly used detection method is gas chromatography.Therefore,it is of great practical significance to strengthen the research on pyrethroids in animal foods.This paper mainly focuses on the characteristics of animal food samples with high protein and fat content.I researched the analysis and detection technology of pyrethroid residues in animal foods,and the rapid detection methods were established bifenthrin and fenpropathrin,λ-cyhalothrin,permethrin,etofenprox,β-cyfluthrin,β-cypermethrin,flucythrinate,fenvalerate,deltamethrin,and fluvalinate 11 kinds of pyrethroids in animal foods.The main contents and results of this study are as follows:1.A detection method has been established for 10 pyrethroids（withoutβ-cyfluthrin）in animal foods by UPLC-MS/MS.Sample pretreatment conditions（including extraction solvent,extraction method,freezing time,adsorbent and constant volume solvent）,chromatographic conditions and mass spectrometry conditions were optimized.Finally,it was determined by extraction with glacial acetic acid-acetonitrile（1:99,V/V）and most of the grease were removed by cryogenic freezing,and then further purified by Z-Sep⁺and C₁₈.0.1%formic acid aqueous solution（containing 5 mmol/L ammonium acetate）was used as the mobile phase,ACQUITY HSS T3 column was used to separate,electrospray ionization and multiple reaction detection mode were performed.The linear correlations of the 10 pyrethroids in the range of 2.5 to 100μg/L were good,and the correlation coefficients were all greater than 0.997.The recoveries were all 70.3%to 119.9%,the relative standard deviation（RSD）was 1.2%to 11.2%at the three spiked samples levels of 10,50 and 100μg/kg.The detection limit of the method was 0.9 to 2.4μg/kg and the limit of quantitation was 3.0 to 8.0μg/kg.The pretreatment of this study is simple,sensitive and accurate,and the target can be detected within 10 minutes.It is suitable for rapid detection and analysis of 10 pyrethroid residues in animal foods.2.A detection method has been established for 10 pyrethroids（without fluvalinate）in animal foods by GC-MS/MS.Chromatographic conditions（including the GC column,temperature program and injection temperature）and mass spectrometry conditions were optimized.The matrix effects of 10 pyrethroids in samples were analyzed,matrix-matched standard solutions were used to attenuate matrix enhancement influence and external standard method was chose to quantificate.VF-17MS capillary column was used to separate,electron ionization and multiple reaction monitoring method were performed.The linear relationship among the 10 pyrethroids was good in the range of 10 to 500μg/L,and the correlation coefficients were all greater than 0.997.The recoveries of the blank samples were all 70.6%to115.3%at the three spiked samples levels of 10,50,and 100μg/kg,the relative standard deviation（RSD）was 0.9%to 5.8%.The detection limit of the method was 1.7 to 3.0μg/kg and the limit of quantification was 5.5 to 10μg/kg.At the same time,the effect of chromatographic separation is good,and the multi-residue analysis of 10 targets can be completed within 24minutes.Therefore,the results of this study provide an effective detection method for the detection of pyrethroid residues in animal foods.3.For the 40 samples purchased,including Penaeus penicillatus,Scylla serrata,pork and duck,the samples were analyzed by UPLC-MS/MS and GC-MS/MS respectively.β-cypermethrin and fluvalinate were detected in Penaeus penicillatus;cypermethrin and deltamethrin were detected in Scylla serrata;λ-cyhalothrin andβ-cyfluthrin were detected in pork;fluvalinate and deltamethrin was detected in duck,but they did not exceed the limit requirements.