| With the development of stock raising, all kind of antibiotics had been used as veterinary drug, for example penicillins, tetracyclines, aminoglycosides, sulfonamides and chloramphenicols. They are used for the treatment of bacterial diseases and promotion of growth. The residues of veterinary drug had been appeared In animal derived food as the illogicality application of veterinary drug. In China, the production and processing of eel is mainly concentrated in Fujian province. Intensive aquaculture faming techniques using higher stocking densities does result is an increased occurrence of diseases. Quinoxalines. Quinolones, Sulphonamides are frequently used fight disease in eel. This thesis focus on developing the analytical methods for monitoring some drag residues in eel by liquid chromatography-tandem mass spectrometer, the main research area in this thesis can be included as follows:1 A liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of three commonly used quincxalines residues in eel and eel products has been developed. Tissues are extracted with acidic acetonitrile-methanol mixed solvent, and purification with HLB solid phase extraction (SPE) cartridge, followed by liquid chromatography-tandem mass spectrometry analysis. The extraction was separated by reverse phase liquid chromatography using 30% acetonitrile plus 70% acidified water with 0.1% formic acid as the elution solvents at 0.4ml/ min drip rate,confirmation and quantification by mass spectrum in the select reaction monitoring(SRM) mode via positive electrospray ionization (+ESI), the SRM transition m / z272, the parent ion of CYX, to m /zl88and 143, transitionm/ z263(CDX)to 231 and 131, transition m / z175(QCA)to 147 and 131. The structure was parsed by full scan mode. The linear ranges of the cyadox, carbadox,quinoxaline-2-carboxylic acid are between 0.03-100ng, and the linear correlation coefficient r>0.998.In the ranges of 2-10μg/kg,mean fortification recoveries are between 69.10%-93.54%,the relative standard deviation are 2.49%-9.03%.Limits of detection are 2-3μg/kg. 2 A reversed-phase high-performace liquid chromatographic method with tandem mass-spectrometric detection was developed for the simultaneous analysis of qunolones and sulfonamides in eel and eel products. The analyses were extracted with dichloromethane + acetonitrile=5+95 (v/v) , and then cleaned up with HLB solid phase extraction(SPE) cartridges, followed by liquid chromatography-tandem mass spectrometry analysis. The linear ranges of the qunolones and sulfonamides are between 2-100μg/L and the linear correlation coefficient r>0.990. In the ranges of 2-20μg/L, mean fortification recoveries are between 62.36%-101.67%, the relative standard deviations are 2.37%-10.62%. Limits of detection are 2μg/kg. The results showed that the established method was quite suitable for identification and quantization of qunolones and sulfonamides.3 The experimental results showed that the established liquid chromatography-Tandem Mass Spectrometry analysis method was special; it can be quickly and accurately determine the quinoxalines, qunolones and sulfonamides residues in complex eel and eel products. The experimental results of the three types of drugs can provide drug application reference, safety and efficacy for the cultivation industry, it also can provide the basis for how to use clinical rational drug and develop drug off period. This is an important theoretical and practical significance to monitor eel, eel products residue and protect people's health. In addition, established method can resolve lag technical standards of China's export products in eel and play a positive role in crossing TBT. |
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