Preparation And Application Of Chloramphenicol Molecularly Imprinted Polymer

Chloramphenicol?CAP?is a broad-spectrum antibiotic.It has a good antibacterial effect and has been widely used in animal husbandry and aquaculture.However,the side effect of CAP is large.It can not only cause aplastic anemia,granulocytic deficiency,and gray infant syndrome,but also lead to drug resistance in the long term.The residue of CAP has been strictly regulated in many countries.However,due to its wide range of application,low price,and stable antibacterial,there is still illegal use of CAP in the breeding industry.Molecular imprinting technique is also known as molecular template technique.Itrefers to the preparation of a specific selective polymer with a specific target molecule as the template.Molecular imprinting technique has been developed rapidly because ofits structure specificity,specificity,selectivity,and wide availability.At present,thetechnology is widely used in solid phase extraction,drug separation,molecularly imprinted sensor,mimic enzyme catalysis,and other fields.Inorder to improve the specific adsorption of molecularly imprinted polymer?MIPs?incomplex matrix animal derived foods,molecular simulation has been widely used inthe design of MIPs in recent years,which provides theoretical guidance forthe preparation of MIPs.Using Gausian 09 software,the B3LYP,LC-WPBE,PBEIPBE,and?B97XD methods with6-31G?d,p?and 6-31+G?d,p?basis sets have been employed to simulated the molecular structure of CAP.The results show that the?B97XD method is more suitable for molecular imprinting system of CAP.Using the optimized method,the bonding effect and binding energy of CAP are simulated with the methacrylic acid?MAA?,acrylamide?AM?,itaconic acidine?IA?,and4-vinyl pyridine?4-Vpy?as the functional monomers..The results showed that the stable complex formed by MAA and CAP had the lowest binding energy.And the interaction was the strongest.The imprinting efficiency of CAP-MIPs is expected to be better.The bond number,binding energy,and interaction mechanism of the stable complex formed by CAP and MAA at different imprinted molar ratios were investigated when the MAA was as the function monomer,the ethylene glycol dimethacrylate?EGDMA?,pentaerythritol triacrylate?PETA?,and trimethylolpropane trimethylacrylate?TRIM?were as the cross-linking agents,and the acetonitrile,methanol,acetone,tetrahydrofuran,water,and toluene were asthe solvents,respectively.And the cross-linking agent and solvent werealso optimized.Imprinting the essence of the interaction between CAP and MAA was discussed by the atom in molecular theory?AIM?.The results show that imprinted molecular CAP and functional monomer MAA were interacted by the hydrogen bond.When the molar ratio of CAP and MAA is 1:10 and the PETA is as the cross-linking agent,the ordered complexes of CAP and MAA have the largest number of hydrogen bonds,the lowest binding energy,and the most stable configuration in toluene solvent.With the guidence by the theoretical research,the CAP-MIPs were prepared by precipitation polymerization when the MAA was used as the functional monomer,the PETA was as the cross-linking agent,and the acetonitrile was as the solvent.Their adsorption properties were measured by the equilibrium adsorption experiment.The experimental results show that when the imprinted molar ratio of CAP to MAA is 1:10,the prepared CAP-MIPs is spherical with an average diameter of 285.09 nm.Its maximum adsorption capacity is 8.08 mg/g.The scatchard analysis results show that the CAP-MIPs has a binding site for CAP.The dissociation equilibrium constant?K_d?and the maximum apparent adsorption capacity(Q_max)of the binding sites were 2091.66 mg/L and 173.3 mg/g.The selective test showed that the adsorption capacity of CAP-MIPs to CAP was higher than that of thiamphenicol?TAP?and florfenicolone?FF?.And the CAP-MIPs showed the best specific adsorbability of chloramphenicol.Finally,the CAP-MIPs piezoelectric sensor was prepared according to the CAP-MIPs modifying the quartz crystal microbalance?QCM?electrode via the entrapping method,in which the polyvinyl chloridem?PVC?and tetrahydrofuran were selected as the investment materialand solvent,respectively.The detection conditions of sensors are optimized by the experiments.The CAP-MIPs piezoelectric sensor was applied to determination of chloramphenicol in honey samples.The results show that the sensor has the best response when the amount of CAP-MIPs?NIPs?is 50 mg and the volume of coating amount is 15?L.The regression equation of the sensor is y=-7.655-5.487x with the CAP standard concentrations of 10⁸00 ng/mL under the optimized conditions,and the corresponding limit of detection?LOD?is 19.41 ng/mL.The recovery rate of CAP in honey samples is 94.35%⁹8.99%with multiple cycles,using the sensor.