Analytical Methods Of Drug And Metabolite Residues In Food Of Animal Origin Based On QuEChERS

Drug residues in food come from a wide range of sources,posing a major threat to human health.Existing testing standards are still not comprehensive in terms of drug residues.Accurate detection and quantification of various drug residues in food can ensure the safety of human life,which is conducive to the fate and transformation of research drugs.The development of drug residue testing in food is of great significance.The matrix of food samples is more complicated,which brings great difficulties to the detection of drug residues.QuEChERS method(Quick,Easy,Cheap,Effective,Rugged,Safe),as a common pretreatment technology for animal and plant samples,can adsorb impurities in the sample and extract the desired target.The method is simple to operate and has a low cost.In this article,the multi-residue analysis of xylazine,2,6-dimethylaniline(DMA),tiamulin,vornimulin,and 8-α-hydroxymullin in animal-derived foods was carried out to accurately quantify the results.The developed method is of great significance for the actual sample detection.The main research work is as follows:A novel analytical method for simultaneous determination of xylazine and its metabolite-2,6-dimethylaniline(DMA)in pork meat based on QuEChERS/liquid chromatography-mass spectrometry(LC-MS/MS)was developed.Pork meat samples were homogenated followed by extraction with acetonitrile,cleanup with C18-PSA mixed adsorbent.The extracts were evaporated to dryness with high-purity nitrogen gas,and then dissolved in the mobile phase A for LC-MS/MS analysis under positive ionization mode using multiple reaction monitoring(MRM).The separation was carried out on a C18 separation column(2.1 mm x 150 mm,5 μm)using 0.1%(v/v)formic acid-water(A)and0.1%(v/v)formic acid-acetonitrile(B)as mobile phases.The quantification of xylazine and DMA was completed by a matrix-matched external calibration method.The limits of detection were 0.1 ng/g and 0.3 μg/kg for xylazine and DMA,respectively.The recoveries of xylazine and DMA were 95.4%-108.0% and 71.4-80.2%,respectively,with the relative standard deviations(RSDs)of 2.3%-6.9%.The proposed method has been successfully applied to the measurements of xylazine and DMA in pork meat samples from local supermarkets.The present method is simple,fast,sensitive,and is suitable for the analysis of xylazine and DMA residues in pork meat.The extraction and detection methods of tiamulin,valnemulin and 8-α-hydroxymulin in poultry eggs samples were studied.The experiment compares the four extraction solvents and the acidic conditions of the extraction solvent to screen the best extraction conditions,while changing different adsorbents to select the best purification method.After homogenization,the samples were extracted with acetonitrile and purified with a C18-GCB mixed adsorbent.The extracted solution was separated on a C18 chromatographic column(2.1 mm x 100 mm,3.5 μm)after constant volume.The detection limits of tiamulin,8-α-hydroxymulin,and vornemulin were 0.00031 μg/kg,13.8 μg/kg and 0.00030 μg/kg,respectively,and the recoveries were 89.6%-121.2%(tiamulin),124.8%-127.8%(8-α-hydroxymulin),89.8%-106.7%(valnemulin).After methodological verification,the method has been successfully applied to the detection of tiamulin,valnemulin and 8-α-hydroxymulin in eggs of various brands on the market.It has the advantages of accuracy,efficiency and simple operation.A fast,efficient and simple QuEChERS pretreatment method was used to successfully purify pork and egg samples in this work.We optimized the pretreatment conditions,and analyzed the multiple residues of five drugs such as serazine combined with liquid chromatography-mass spectrometry.At the same time,the accuracy and reliability of the experiment were studied through methodological verification,and the matrix effect was systematically analyzed and evaluated.The method has been successfully applied to the detection of actual samples and meets the requirements of national standards and daily needs.