| Cephalosporins have the characteristics of broad spectrum antibacterial and strong bactericidal. They havebeen widely used in the veterinary clinic. The human health is threatened by the cephalosporins residues from food of animal origin, because people breach the rules of the provisions and misuse the cephalosporins.Therefore, The effective monitoring of the drug residues from food of animal origin should be strengthened to protect the food security from animal origin. The research of Cephalosporins residues focuses on the methods of efficient, selective, simple and environment-friendly determination of the residues. This sentence can be deleted.1. Establishing the method of mimultaneous determination of CRD,CLX,CPZ and CEZ by HPCEIn this paper, the effects of separating the four drugs were studied in different conditions buffer concentration,buffer pH,running voltage and operating temperature) The results of the orthogonal experiment analysis showed that the best condition is as follows:40mmol/L Citric acid - Disodium hydrogen phosphate buffer (pH7.5),running voltage 20 kV and operated temperature 20℃, detection wavelength 210nm. The four cephalosporins could be separated completely under this condition.The liner range is 3.125μg/mL ~100μg/mL . RSD for peak area are less than 3%. RSD of migration time are less than 0.5%.2. Preparation and evaluation of MIP with 7-ACA7-ACA is the nucleus of cephalosporins, the molecular imprinted polymer was prepared by Situ polymerization with 7-ACA as the template molecule, MAA as functional monomer and EDMA as the cross linkers. The effects of preparing MIP with different mounts of template molecule, functional monomer and cross linkers were studied. The best polymerization conditions were determined by desiring the orthogonal assay and optimizing the conditions.The results showed that the molar ratio of template molecule and functional monomer and crosslinker was 1:10:23, and polymerization temperature was 55℃in the best condition.Evaluating the MIP by combining experiments and Scatchard analysis. The results showed that: the MIP recogniz the template with two classes of binding sites : The dissociation contents (Kd) and the apparent maximum binding capacity(Qmax) of the high affinity sites was 2.12mmol/L and 89.3 mol/g.The dissociation contents(Kd) and the apparent maximum binding capacity(Qmax) of the low affinity sites is 0.0037 mmol/L and 68.8 mol/g. MIP was significantly higher than NMIP on the adsorption of 7-ACA, and it had strong adsorption on the cephalosporins.3. Preparing the MISPE column with7-ACA and evaluation of the method of MISPEIn this experiment, The MISPE column was prepared with 7-ACA molecularly imprinted polymer as the filler and empty polypropylene SPE tube as the column. Through selecting the eluent and the eluent , establish the method of imprinted solid phase extraction. Establishing the method of imprinted solid phase extraction cephalosporins by screening the eluting reagent and the eluant. In this method ,the recovery of the four drugs were more than 80%.4. The Comparison of Pre-treatment methods with detect cephalosporins in chicken muscle tissueThe test add a standard to blank chicken muscle,then detect the recovery. Compared three kinds of pre-treatment methods with SE,SPE and MISPE.And study the effect of purification by HPCE. The results showed that:in these pre-treatment methods, the recovery of drugs is 93.9%～108.2%,74.4%～80.6%,80.5%～82.6%. MISPE has the best of purification, SPE ranks the second, SE is the worst.5.The application of detect cephalosporins in chicken muscle tissues with HPCEThe test detect chicken muscle sample by the method of MISPE-HPCE. The recovery of four drugs is more than 80%.It has low background impurity. Meet the requirements of veterinary drug residue analysis. |
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