Preparation And Performance Research Of Dibutyl Phthalate Molecularly Imprinted Polymers

Dibutyl phthalate?DBP?is a common plasticizer and it is called an endocrine disrupter because it is poisonousness to human body.It can cause cancer,deformities and genetic mutations in an organism's endocrine system,even at very low concentrations.Surface molecular imprinting technology,which provides us with an effective method to synthesize surface molecularly imprinted polymers?SMIPs?with specific molecular recognition properties,has attracted considerable attention in recent years.Semiconductor nanocrystals,known as quantum dots?QDs?,have attracted extensive attention and application due to their good biocompatibility,excellent photostability and relatively high fluorescence intensity.Several QD based sensors have been developed for the assay of metal ions,biomolecules,cell and small molecules.In this paper,by combining the strong fluorescence property of the ZnS:Mn QDs with the high selectivity of molecular imprinting,we prepared three kinds of fluorescence molecularly imprinted polymers which used DBP as template molecules to adsorb DBP specifically.The mainly includes the following sections:?1?Three groups of molecularly imprinted polymers with the monomer of 200mL?P1?,250mL?P2?and 300mL?P3?were prepared using DBP as the template molecule,3-aminopropyltriethoxysilane?APTES?as the functional monomer and the tetraethoxysilane?TEOS?as the cross-linker.Then,MIPs-ZnS:Mn QDs with largest quenching efficiency were selected for the following experiment.The products MIPs-ZnS:Mn QDs were characterized by transmission electron microscope,Fourier transform infrared spectroscopy,X-ray diffraction and fluorescence spectroscopy.In addition,optical stability and the effect of pH on the fluorescence intensity were evaluated.After the experimental conditions were optimized,a linear relationship was obtained covering the range of 5.0-50? mol L-1 with a correlation coefficient of 0.9970.The developed method was applicable to routine trace determination of DBP in real examples,the average recovery rate of DBP at three spiking levels is more that 98.1% with RSDs below 5.5%.?2?The fluorescence molecularly imprinted polymers?SiO₂@QDs@MIPs?based on ZnS:Mn QDs with excellent optical properties and molecularly imprinted polymer with molecular recognition ability were successfully synthesized by precipitation polymerization.The prepared SiO₂@QDs@MIPs were characterized by transmission electron microscopy?TEM?,scanning electron microscopy?SEM?,fourier transform infrared spectroscopy?FT-IR?,X-ray diffraction?XRD?,thermo gravimetric analysis?TGA?and fluorescence spectroscopy.The rusults showed that the SiO₂@QDs@MIPs are highly spherical with a smooth surface and the MIPs layer could be estimated to be about 5nm in thickness on the surface of SiO₂ nanoparticles.After the experimental conditions were optimized,the linear relationship between fluorescence intensity and the concentration of DBP was obtained from 5 to 50?mol L-1,with a correlation coefficient of 0.9974.The SiO₂@QDs@MIPs were successfully applied to tap water sample analysis,and recoveries in the range of 97.80-103.33% were attained at three spiking levels of DBP,with precisions below 3.25%.?3?Three types of magnetic fluorescence molecularly imprinted microspheres with different molar ratios of the template?DBP?and functional monomer?AM?involving 1:2,1:4,and 1:6 were prepared for recognition and separation of DBP.Then,the Fe₃O₄@SiO₂-QDs-MIPs with largest quenching efficiency were selected for the following experiment.The composite integrated the high selectivity of MIPs,strong fluorescence property of ZnS:Mn QDs and easy separation of magnetic nanoparticles.The prepared polymers were characterized by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,Fourier transform infrared spectrometer?FT-IR?,X-ray diffraction?XRD?,vibration sample magnetometer?VSM?and fluorescence spectroscopy.The Fe₃O₄@SiO₂-QDs-MIPs were demonstrated with spherical shape and core-shell structure,and exhibited magnetic property?Ms=17.20 emu g-1?and optical stability.A linear relationship between the fluorescence intensity and the concentration of DBP had been obtained covering the concentration range of 5.0-50?mol L-1 with a detection limit of 0.08?mol L-1.Furthermore,the Fe₃O₄@SiO₂-QDs-MIPs were successfully applied to tap water sample analysis,and recoveries are more than 99.45% were attained at three spiking levels of DBP,with precisions below 3.37%.