Determination Of Veterinary Drug Residues In Livestock And Poultry Products By QuEChERS Combined With Ultra Performance Liquid Chromatography-High Resolution Mass Spectrometry

Based on QuEChERS method and ultra performance liquid chromatography-tandem UPLC-Q Exactive orbitrap HRMS technology（UPLC-Q Exactive Orbitrap HRMS）,this paper studied and established the analytical method to detect the 59 kinds of veterinary drug residues,β-adrenergic agonists,Quinolones,Sulfonamides,Tetracyclines,Malachite green,Nitiomidazoles,Macrolides,Lincomycin,Amide alcohols,MQCA,Steroid hormone and Chlorpromazine in livestock products.The main work and results of this paper were as follows:1.Taking pork as an example,a method for rapid detection and analysis of veterinary drug residues in animal-derived foods by QuEChERS-UPLC-Q Exactive Orbitrap HRMS was established.According to the QuEChERS method,the sample was using 0.1 mol/L Na₂EDTA aqueous solution and acetonitrile as the extraction solvent,Anhydrous sodium sulfate as the dehydrating agent,Octadecylsilane（C18）and ethylenediamine-N-propylpropylsilane（PSA）as the purifier,Methanol-0.1%formic acid water（4:6,v/v）as a redissolution solution by optimizing the parameters and conditions of the method.Then,chromatographic analysis was carried out using a Waters ACQUITY UPLC^?BEH C18（100 mm×2.1 mm i.d.,1.7μm）column with methanol-0.1%formic acid queous solution as mobile phase by gradient elution,and 59 veterinary residues were analyzed by high-resolution mass spectrometry.In addition,the matrix effect was evaluated,and the external standard method was used to quantitatively eliminate the influence of matrix effect on the analytical results.2.A method validation test was performed on the QuEChERS-UPLC-Q Exactive Orbitrap HRMS for the complex matrix of pork.The results showed that the calibration curves of 59 veterinary drugs were linear in their respective linear ranges,whose correlation coefficients were more than 0.9950.The average recoveries of 59 analytes ranged from65.71%to 119.08%at three different spiked concentration levels of 5,20,50μg/kg.Relative standard deviations（RSD）were less than 10%,the limits of quantitation（LOQ）were 0.1².0μg/kg.In this experiment,the method was established to apply for 40 samples,the results showed that 2 samples of pork were found to contain florfenicol residues,which were 0.526μg/kg and 1.869μg/kg,respectively,and the others were all qualified.This proposed method verified by the actual sample,is simple,reliable,accurate,efficient,rapid and can be applied for highthroughput screening and confirmation of multiple veterinary residues in pork.3.Taking pig kidney,fish and chicken as the object,the experiment further applied the optimized pretreatment method and chromatographic mass spectrometry conditions to the detection of veterinary drug residues in other animal-derived foods,methodological verification was carried out on the accuracy,linearity and applicability of the method.The results showed that 59 kinds of target compounds in the three matrices were a good linear relationship in the corresponding concentration range,whose correlation coefficients were more than 0.9950.The average recoveries of 59 analytes ranged from 54.13%to 106.38%（pig kidney）,57.68%to 111.85%（fish）,and 55.36%to 109.85%（chicken）at three different spiked concentrations levels of 5,20,50μg/kg in the three matrices,and relative standard deviations（RSD）were less than 10%.In addition,the limit of quantitation of 59 compounds in the three matrices ranged from 0.1 to 5.0μg/kg.In this experiment,the QuEChERS-UPLC-Q Exactive Orbitrap HRMS method was applied to the detection of 30 samples（10 pig kidney,10fish and 10 chicken）,and one positive sample of pig kidney was detected to contain florfenicol residues,which was 1.784μg/kg,and the rest of the samples were all qualified.In short,the method is highly quick,simple,sensitive,effective,safe,and can also meet the requirements for simultaneous detection of multi-residues of veterinary drugs in livestock products.