Preparation And Properties Study Of Ethopabate Molecularly Imprinted Polymers

As a broad-spectrum coccidiostat, ethopabate(ETP) plays a quite important role in prevention and treatment of chicken coccidiosis. While, the inappropriate utilization of ethopabate is easy to lead to the drug residues of chicken tissues exceeding the limit standard, which can pose a threat on human health immediately.As a consequence, the controlling and detection of ethopabate in chicken tissues is extremely important.Molecular imprinting technology is a novel artificial-synthesized technology, synthesising functional materials with high adsorption capacity of the target molecules. Molecularly imprinted polymers have the advantages such as predetermination, specific recognition, chemical stability and wide practicability. They have been widely applied in the food inspection, chemical analysis, pharmaceutical separation and monitoring, etc.In this paper, based on the novel functional monomer which named N,Obismethacryloyl ethanolamine(NOBE), suspension polymerization and surface molecular imprinting technique were employed to prepare ETP-MIPs first. Then the ETP-MIPs were used as adsorption filler to prepare molecularly imprinted solid-phase extraction column with higher sensitivity and accuracy, used for the separation and concentration of ETP in chicken tissues.The main research contents are as follows:1. The novel functional monomer which named NOBE was synthesized.2. In order to investigate thoroughly the interaction and recognition mechanism of ETP-MIPs,the pre-organization system was studied by computer simulation and differential ultraviolet spectrum research,to providing theoretical direction for the preparation of ETPMIPs.In the computer simulation approach,density functional theory and PM3 semiempirical method were used for the configuration optimization, charge distribution and energy calculation of the template molecules ETP, functional monomer MAA, AM, NOBE, and their complexes. It indicated that NOBE was the most appropriate functional monomer. The differential ultraviolet spectrum research showed that the ETP and NOBE can combined through collaboration hydrogen bond to pre-organized with the complex ratio of 1:2.3. Based on the novel functional monomer NOBE, ETP-MIPs were prepared by suspension polymerization method.When the ratio of template-functional monomer was 1:2, the imprinting effect of ETP-MIPs was best.The Scatchard analysis indicated that there were two classes of binding sites in ETP-MIPs; the equilibrium dissociation constant and apparent maximum binding capacity of high affinity sites and low affinity sites were calculated, respectively were Kd1=1.051 μg/m L, Qmax1=0.309 μg/mg; Kd2=0.220 μg/m L, Qmax2=0.108 μg/mg.4. Based on the novel functional monomer NOBE, ETP-MIPs were prepared by surface molecular imprinting technique with the silica gel as a support matrix. Via orthogonal experiment, the ratio of template-functional monomer, template-crosslinking agent and the types of porogen, were investigated,in order to optimize the polymerization conditions.The results of orthogonal experiment showed that, the primary and secondary order of three factors was the types of porogen>the ratio of template-functional monomer>the ratio of template-crosslinking agent; when the polymerization conditions were acetonitrile used as porogen, the ratio between template-functional monomer-crosslinking agent was 1:2:20, the imprinting effect was best, which reached 2.804. The Scatchard analysis indicated that there were two classes of binding sites in ETP-MIPs; the Kd and Qmax of high and low affinity sites were calculated, respectively were Kd1=1.608 μg/m L, Qmax1=1.101 μg/mg; Kd2=0.109 μg/m L, Qmax2=0.172 μg/mg.5. ETP-MIPs were used as the adsorption filler to prepare molecularly imprinted solidphase extraction column.The optimization of solid-phase extraction conditions suggestted that 2m L acetonitrile used as the sample solvent, 2m L hexyl hydride used as the leaching solvent, 5m L methanol-acetic acid(V: V, 9:1) used as the elution solvent, the MISPE presented a better adsorption efficient than NISPE and C18-SPE, with the recovery rate reached 90.6%. Used in the separation and concentration of ETP in chicken tissues, the spiked recoveries of three concentration levels were 88.0%~90.8%, the relative standard deviations were less than 3%。...