Determination Of Multiple Pesticides And Veterinary Drugs Residues In Complicated Foodstuff Samples

(1)A simple,selective and sensitive method was introduced to determine 106 pesticides in the complicated nuts sample by ultra-high pressure liquid chromatography coupled to a tandem mass spectrometer(UHPLC-MS/MS).After extracted by the high efficiency of microwave-assisted solvent extraction(MAE),the sample was purified by a two-step cleanup method combining freeze-out with dispersive solid-phase extraction.Guaranteed by the successful pretreatments to the dried and fat nut samples,average recoveries for 106 analytes ranged from 75.3% to 119.3%,(relative standard deviations <13%)at three concentrations levels.The limits of detection and quantification were in the ranges of 0.3-3.0 ?g kg-1 and 1.0-10.0 ?g kg-1 respectively.It was suitable for determination the pesticides in nut samples.(2)It is rather challengeable to extract hydrophobic pesticides from the complicated matrices which contain relatively high fatty compounds and ensure high recoveries of target analytes and low levels of co-extracted.This paper introduces a simple,quick and sensitive method for the determination of 8 benzoylurea insecticides(BUs)in nuts via gel permeation chromatography(GPC)cleanup coupled with high performance liquid chromatography-tandem mass spectrometry(LC-MS/MS).By this method,no significant matrix effects were observed.Calibration curves for 8 BUs showed good linearity in the range of 10.0 to 500.0 ?g kg-1 with correlation coefficients in excess of 0.9990.Meanwhile recoveries of them were between 82.8-113.2% with relative standard derivations lower than 11% at three spiked concentration levels in real samples in walnut,badam,and sweet almondand.Limits of quantification were ranged from 1.8 to 9.7 ?g kg-1.It proved that the proposed analytical method can be promising technique for the simultaneous determination of multi hydrophobic pesticides in nut and other foodstuff samples with high fat content.(3)This paper introduces a simple,selective and sensitive method to determine 145 pesticides in the high sugar content and low water content dried fruit sample by ultra-high pressure liquid chromatography coupled to a tandem mass spectrometer(UHPLC-MS/MS).The microwave-assisted solvent extraction(MAE)improved the extraction efficiencies of both spiked samples and real positive samples.After cleanup by PSA,the matrix effect was reduced.Average recoveries for 145 analytes ranged from 67.8% to 119.4%,(relative standard deviations <16.7%)at three concentrations levels.This method was economy,sensitive,and effevtive and it was suitable for determination the pesticides in high sugar content samples(4)A simple,selective and sensitive sample preparation methodwas developed and validated for multi-class analysis ofveterinary drug residues in kidney and liver.Sample preparation procedure was performed using phosphate buffer solution for protein precipitationand followed by ultra-high-performance liquid chromatography tandem mass spectrometry(UHPLC-MS/MS)analysis.Guaranteed by the successful pretreatments to the samples,average recoveries for 48 analytesranged from 77.5–118.4%,(relative standard deviations <15%)at three concentrations levels.The limits of detection and quantification were in the ranges of 0.3-3.0 ?gkg-1 and 1.0-10.0 ?gkg-1 respectively.Furthermore,it was successfully applied into thedetermination of pesticides in 60 real samples.