Preparation Of Renewable Smart Responsive Imprinting Materials And Their Application In SERS Detection Of Antibiotics

Globally,there are more than 100,000 tons of antibiotics used in human and veterinary medicines every year,but only a few therapeutic antibiotics can be absorbed and metabolized by the human body.Among them,50%～90%of the antibiotics will pass through feces and urine in the form of original drugs.After being excreted from the body,antibiotics and their metabolites enter the water environment through various channels.However,ordinary water purification processes are almost ineffective in removing antibiotics and their metabolites,and many countries and regions have banned some antibiotics from being detected.Therefore,it is particularly important for the degradation and detection of antibiotics in environmental samples.Nowadays,the detection methods of antibiotics mainly include high performance liquid chromatography,mass spectrometry and capillary electrophoresis,which have low detection limit and high accuracy.However,these methods still have the disadvantages of expensive instruments and complex pretreatment.As a new non-destructive rapid detection technology,Surface Enhanced Raman Spectroscopy（SERS）has high sensitivity and can provide fingerprints for analytes.Molecularly imprinted polymers（MIP）are widely used in the adsorption and separation of environmental pollutants because of their high adsorption selectivity and large adsorption capacity.Therefore,the combination of MIP and SERS technology will show great potential and application prospects in the analysis test.At the same time,the introduction of intelligent response materials into MIP-SERS technology can increase the controllability of materials.Therefore,this paper synthesized a series of intelligent responsive imprinting materials,and combined with SERS technology,analyzed and detected several antibiotics.Specific contents are as follows:（1）A novel molecularly imprinted photocatalytic material（TiO₂-DR/MIPs）was successfully prepared by surface initiated atom transfer radical polymerization（SI-ATRP）with ofloxacin as the template molecule.The morphology and properties of the material were characterized by TEM,XRD,FTIR and TG.The temperature and pH sensitive properties of the materials and their effects on the photocatalytic degradation efficiency of ofloxacin were studied respectively.The selectivity and stability of the materials were explored.The results show that the particle size of TiO₂-DR/MIPs can respond well with the change of temperature and pH,and the photocatalytic activity of TiO₂-DR/MIPs can be regulated by changing the ambient temperature and pH.TiO₂-DR/MIPs has a good selective degradation of ofloxacin,and good stability and reuse effect.After four photocatalytic degradation cycles,the photocatalytic efficiency is only reduced by 5%.In addition,the double-sensitive molecularly imprinted layer in TiO₂-DR/MIPS can effectively prevent the agglomeration of TiO₂ and realize the uniform dispersion of TiO₂.（2）On the basis of（1）,a new SERS substrate（TM@TiO₂@Ag）with intelligent response property was successfully synthesized by introducing silver nanoparticles,which improved the selectivity of traditional SERS detection method and gave the SERS substrate material reproducible under ultraviolet light irradiation.First,hollow titanium dioxide was prepared with SiO₂ as sacrificial template molecule,and then modified with NH₄⁺,and combined with CO₃^2-modified silver by electrostatic adsorption.Finally,using ofloxacin as the template molecule,a thermo-sensitive molecularly imprinted photocatalytic material with intelligent responsive gel grafting TiO₂@Ag was prepared by free radical polymerization method.The properties and morphology of TM@TiO₂@Ag were characterized by TEM,SEM,FT-IR,UV-vis,EDX,XPS and XRD.The results show that TM@TiO₂@Ag has a uniform spherical structure,and has good selectivity,sensitivity and stability for ofloxacin.The detection limit is 11.14 p M.In addition,it has been proved that TM@TiO₂@Ag has good temperature sensitivity and recoverability.（3）On the basis that TiO₂ photocatalyst mentioned in（2）can realize Tm@TiO₂@Ag material regeneration under ultraviolet light irradiation,this chapter combined Ag@Cu₂O and molecular imprinting technology to successfully synthesize a SERS substrate（TM@Ag@Cu₂O）which can realize regeneration under visible light irradiation.TEM,SEM,FT-IR,UV-Vis,EDX,XPS and XRD were used to analyze the structure,morphology and properties of the substrate materials.The SERS properties of TM@Ag@Cu₂O were studied by Raman microscopy.Finally,it was applied to the rapid trace detection of tetracycline in water.The results showed that the prepared TM@Ag@Cu₂O had good sensitivity,selectivity and reproducibility.In addition,the substrate has a low detection limit of 0.023 nM for tetracycline.