Study On Preparation Of Several Veterinary Drug Moleculars Surface Imprinted Materials And Their Properties

This paper via surface-initiated atom transfer radical polymerization (SI-ATRP) technology prepared CGA molecular imprinted polymer as chromatographic packing. Study of the effect of chromatographic conditions for separation and the adsorption and recognition capacity of the stationary phase for CGA and its analogs. Silica as the substrate prapred TC surface molecularly imprinted materials and PGMA-EDMA microspheres as the substrate were prepared prapred ENR surface molecularly imprinted materials by using surface grafting polymerization. The binding properties for template molecules were studied with both static and dynamic methods, and studied the choice performance of surface molecularly imprinted materials. MIPs as peaking of SPE combined with HPLC. The methods of enrichment and separation of trace veterinary drug residues in animal-derived food were investigated, and achieved good results.The paper consists of the following parts:1. A novel chromatographic packing of chlorogenic acid (CGA) molecularly imprinted polymer (MIP) based on the 5.0μm silica was prepared by surface initiated atom transfer radical polymerization (SI-ATRP) from 4-vinylpyridine (4-VP) as functional monomer, ethyl glycol dimethacrylate (EDMA) as cross-linker in the mixture of methanol and water (7:3, v/v) under mild reaction conditions. The characteristics of the CGA MIP were investigated by elemental analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR) and atomic force microscopy (AFM). The effects of some chromatographic conditions such as mobile phase composition and temperature on the retention time were investigated. The adsorption capacity of the stationary phase for compounds was determined by frontal chromatographic technique. The results show that Freundlich isotherm fits the experimental adsorption isotherm data better than Langmuir model does. The relatively high heterogeneity index values regressed with the Freundlich isotherm suggests the formation of fairly homogeneous MIP. Thermodynamic data (ΔΔH and ΔΔS) obtained by Van’t Hoff plots reveal an entropy-controlled separation. The CGA MIP column was shown to be successful for the separation and purification of CGA from the extract of Honeysuckle.2. Silica particles were modified with γ-methacryloxypropyl trimethoxysilane (MPS) as a carrier material. Then the tetracycline (TC) molecular imprinting polymer based on the surface of modified silica (MPS/SiO2) was prepared by adopting the novel surface molecular imprinting technique with tetracycline as template molecule, methacrylic acid as functional monomer, ethylene glycol diglycidyl ether (EGDE) as crosslinker in the 50% aqueous (methanol:acetonitrile=6:7, v/v) solution. The rebinding capacity of MIP was evaluated according to adsorption kinetics and adsorption isotherm. The Scatchard plot revealed that the template polymer system has two classes of binding site. Two structural analogues were chose to study the recognition ability, and the selectivity coefficients for oxytetracycline (OTC) and chlortetracycline (CTC) were 20.11 and 9.07, respectively. The result demonstrated the MIPs have high selectivity and recognition to TC. MIP obtained was used as a selective sorbent for molecularly imprinted solid phase extraction (MISPE) coupled with HPLC. The results showed that good linearity was observed in the range of 150～950μg/L for TC, with a correlation coefficient of 0.9972. Adding level of 300-700μg/L, the average of spiked recoveries of TC is about 81.1%, with a relative standard deviation (RSD) range from 3.0% to 4.4%, the limit of detection (LOD) reached 25 μg/L. The advantages of the proposed method are that it is easy to operate, reliable and applicable to analyze the TC residues in milk samples.3. In this study, the PGMA-EDMA microsphere, for the advantages of low cost, easily prepared and abundant active groups, was selected as an ideal support substrate. Using the grafting method prepared enrofloxacin (ENR) surface molecular imprinted material at the surface of microsphere. The MIP/PGMA-EDMA was characterized by Fourier transmission infrared spectrometry (FT-IR), scanning electron microscope (SEM), and elemental analysis. The results demonstrated that imprinted polymer graft successfully on the surface of microsphere and spherical shaped MIP/PGMA-EDMA particles prepared via surface grafting possessed binding sites homogeneous property. Batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics and selective recognition of MIP/PGMA-EDMA.The maximum static adsorption capacity for ENR of MIP/PGMA-EDMA was 33.30 mg/g, the Scatchard plot revealed that the MIP polymer system has two classes of binding site and the NIP polymer noly has one binding site. The selectivity coefficients k value of ENR and OFL of MIP/PGMA-EDMA are 3.56 and 2.50, which demonstrated MIP/PGMA-EDMA has high affinity and selectivity for template analogs over other antibiotics such as TC. A simple rapid and sensitive method using MISPE combined with HPLC was developed for the determination of ENR from milk samples, the mean recoveries of ENR from milk sample were 92.6-95.6%, with the RSD less than 3.2%. The limit of detection (LOD) was determined to be 10 μg/L, which estimated as three times the signal-to-noise (S/N) ratio.