Studies Of Rapid Determination For Mutil-residues Of Veterinary Drug In Animal Derived Food And Establishment Of The Accurate Mass Library

Veterinary drugs have been widely utilized in the process of current farm practices tocontrol the disease, reduce the mortality, promote the growth, and improve the quality oflivestock. However, due to the overdoses, misuse, and noncompliance of withdrawal time,veterinary drugs might be accumulated in animal derived food, and pose potential threat tohuman health. Therefore, the research and development of multi-residues method forveterinary drug in animal derived food is of great significance. For multi-residues method,the technologies of pretreatment and detection are the main bottleneck. As a novelpretreatment technology, QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe)has been widely utilized in various matrices, which has characteristics of quickness,simpleness and high efficiency. In addition, the development of mass spectrometrytechnology, such as LC-MS/MS and LC-Q-TOF/MS, provided a powerful tool for thequantification and confirmation of multi-class veterinary drugs.Therefore, this studyfocused on these aspects, QuEChERS will be combined with LC-MS/MS andLC-Q-TOF/MS, to established the rapid determination method of multi-residues methodin animal derived food. The main research contents and results are summarized as follows:A novel method for the determination of55multi-class veterinary drug residues indifferent muscle tissues by modified QuEChERS combined with LC-MS/MS is described.The veterinary drugs focused on here belong to several families, such as macrolides,quinolones, sulfonamides, benzimidazoles, and β-agonists. The samples were firstextracted with5%acetic acid in acetonitrile, followed by cleanup with QuEChERS andsequential analysis by LC-MS/MS technique. The acidified acetonitrile could furtherimprove the extraction efficiency for the most of veterinary drug, C18sorbent could alsoremove the lipid material. It was found that the majority of analytes (89.1%) can achievethe mean recoveries between70%and120%in the examined matrices. The repeatabilityand reproducibility are lower than20%for94.1%and90.3%of total analytes in thesematrices, respectively. A coefficient of correlation (2) of0.995or above was obtained for86.7%of the compounds. The range of limits of quantification for these compounds in porcine, bovine and ovine is0.1to18.4μg/kg,0.1to20.0μg/kg, and0.1to18.4μg/kg,respectively. The method was sensitive, accurate, quick and simple, and suitable for theroutine analysis of meat products.A method for the quantification and confirmation of40multi-class antibiotic drugs inhoney by QuEChERS combined with LC-Q-TOF/MS is described. Before analysis byLC-Q-TOF/MS, the sample was diluted with a solution of Na2EDTA-McIlvaine buffersolution, extracted with5%acetic acid in acetonitrile, and cleanup with NH2sorbent. Theaverage recoveries for the majority of analytes (86.9%) were between70%and120%, andrecoveries between different honey matrices were not obvious. The repeatability andreproducibility of the method expressed as the RSDs were less than20%for all analytes.The data acquired by LC-Q-TOF/MS were cross-referenced with an accurate massdatabase of veterinary drugs, and the final confirmation of the compound was based on afull product ions match. Compared with low resolution MS technique, obvious advantageswere obtained in terms of confirmation and identification by LC-Q-TOF/MS. Theapplicability of the method was verified by applying it to12different honey samples, andciprofloxacin residue was detected in the samples.A simple and rapid multi-residue screening method for the quantification andconfirmation of100multi-class veterinary drugs in milk powder by the QuEChERSmethod combined with LC-Q-TOF/MS was developed. The veterinary drugs investigatedbelonged to several families such as macrolides, sulfonamides, quinolones, tetracyclines,nitroimidazoles, benzimidazoles, β-agonists, hormones, and tranquilizers. The sampleswere extracted using a modified QuEChERS procedure:(i) dissolved in a solution ofNa2EDTA–McIlvaine buffer,(ii) extracted with5%acetic acid in acetonitrile, and (iii)purified using a C18sorbent. The average recoveries for the majority of analytes (92.9%)ranged from70%to120%at four concentration levels, while the repeatability andreproducibility ranged from1.1to20.1%. A coefficient of correlation of0.995or abovewas obtained for all the compounds. The range of the limit of quantification for thesecompounds in the milk powder was from0.1to25μg/kg. More than93.0%of the analyteswere detected when present at10μg/kg or less in the milk powder samples. For the screening method, the data of the precursor and product ions of the target analytes weresimultaneously acquired under the All Ions MS/MS mode in a single run. The accuratemass, retention time, and co-elution match of product ion were utilized to identify andconfirm the target compounds. The applicability of the screening method was verified byapplying to ten real milk powder samples, and certain veterinary drugs were detected insome cases.An accurate mass library has been established for112veterinary drugs, it containsthe compound name, molecular formula, retention time, and product ion spectra underdifferent collision energies. The product ion spectra was acquired under the full scan oftarget MS/MS, and this library can been used to screen and confirm the non-targetcompounds. Moreover, based on the product ion spectra, the behavior of fragmentationwere discussed for different classes of veterinary drug, and fragmentation rule weresummarized, which will be a theoretical reference for qualitative analysis and the structureresolution.