Study On Molecular Imprinting Technique Coupled With LC/MS/MS For Analysis Of Tcs In Foodstuff Samples

Tetracyclie antibiotics are intensively used in veterinary medicine and as food additives for growth promotion in the farming industry, and they can product negative effect for human body. So it is very important to develop a fast, high selective method for determination of tetracyclines in foodstuff samples.Molecular imprinting technique is now an established method that can be applied in separation procedures and chemical analyses, and the molecularly imprinted polymers(MIPs) have the characteristics of high ligand selectivity and affinity.Today, solid-phase extraction(SPE) is the most popular sample preparation method ,in order to enhance the selectivity, the use of MIPs as selective sorbents is becoming increasingly popular.Liquid chromatography tandem mass spectrometry (LC/MS/MS) technique frequently provide specific, selective and sensitive quantitative results, and allows unequivocal identification of trace contaminants in complex food matrices, which has become one of the major tools in food analysis.In this thesis, tetracyclies in different foodstuff samples were determined by LC/MS/MS coupled with molecularly imprinted solid-phase extraction (MISPE), and good results were obtained. The major topics in the thesis include:1. In this paper, the importance of food safety, the status of food analysis, the molecular imprinted technology, the basic principle of LC-MS/MS and its application in food analysis were systematically summed up. Synthetic methods of molecularly imprinted polymers and application of the LC/MS/MS in food analysis were particularly outlined.2. MIPs were prepared by precipitation polymerization with tetracycline as the template molecule. Effects of the preparing condition, such as the porogenic solvent, the sorts of the functional monomers and the amount of template on the maximum absorption capacity and imprinted effect of the polymers were investigated by frontal chromatography and selectivity experiment. At last, 6mmol MAA and 65ml acetonitrile/methanol(35:30) were used as functional monomer and porogenic solvent, respectively, the amount of the tetracyclie was 0.75mmol. Under this optimal condition, regulary microspheres were obtained, the values of imprinted factor and Bt were 4.946 and 0.948μmol/g, respectively.3. A MIP that had the highest binding selectivity and capability was used as solid-phase extraction (SPE) sorbents for direct extraction of tetracyclines from different foodstuff samples (panange, pig enteric, fish feedstuff, fish, pork, shrimp, honey). LC/MS/MS conditions and solid-phase extraction protocol were optimized. Under the optimal condition, the recoveries of MISPE were between 70.02%--89.66%, obviously higher than NISPE. tetracycline was determined in panange, pig enteric, fish feedstuff, fish, pork, shrimp, honey samples by MISPE coupled with LC/MS/MS, and good recoveries were obtained, spiked recoveries were from 95.49% to 104.8%, RSD < 10.3%,and limits of detection (LOD) were ng/g.