Study Of Magnetic Imprinted Extraction Materials Based On Carbon Nanotubes

Carbon nanotubes（CNTs） have unique properties and excellent surface area. The magnetic molecularly imprinted polymer based on CNTs not only shows high adsorption capacity and specific selective recognition ability, but also has excellent magnetic property, which has been widely applied in solid-phase extraction field. In this paper, a series of novel magnetic imprinted materials based on CNTs were successfully prepared. Coupled with high performance liquid chromatography and solid phase extraction technology, the imprinted polymers were used to separate, enrich and detect endocrine disrupting chemicals, bioactive constituents and protein in practical sample. The experimental result data showed that the polymer can achieve rapid separation and enrichment toward the template molecule with high selectivity. The main contents are as follow:1. A novel magnetic nonylphenol molecularly imprinted composite extraction materials（MWNTs@Fe₃O₄-MIPs） was prepared based on polyaniline-coated multiwalled carbon nanotubes using nonylphenol（NP） as the template. The structure, morphology and magnetic features of MWNTs@Fe₃O₄-MIPs were characterized by scanning electron microscopy（SEM）, Fourier-transform infrared（FT-IR） analysis and vibrating sample magnetomerter（VSM）. The results showed that a thermally stable magnetic imprinted layer with the thickness of 60 70 nm was coated steadily on the MWNTs surface. Adsorption performance of the MWNTs@Fe₃O₄-MIPs was further investigated by magnetic solid phase extraction（M-SPE） and high performance liquid chromatography（HPLC） technology. The adsorption experimental results indicated that the MWNTs@Fe₃O₄-MIPs possessed high selectivity towards NP with the maximum adsorption capacity of 38.46 mg g^-1. Combined with HPLC technology, the MWNTs@Fe₃O₄-MIP is applied to the separation and the enrichment of trace NP in environmental water samples successfully with the recoveries of 90.0-94.0%..2. A novel, facile and low cost process for imprinting protein on the surface of magnetic multiwalled carbon nanotubes（MMWNTs） was developed using human serum albumin（HSA） as the template and dopamine as the functional monomer. The magnetic imprinted polymers were characterized with transmission electron microscope（TEM）, scanning electron microscope（SEM）, Fourier-transform infrared spectro-metry（FT-IR）, vibrating sample magnetometer（VSM） and thermogravimetric analysis（TGA） in detail. The maximum adsorption capacity of the magnetic imprinted polymers toward HSA was 66.23 mg g^-1 and it took 20 min to achieve the adsorption equilibrium. The magnetic imprinted polymers exhibited the specific selective adsorption toward HSA. Coupled with high performance liquid chromatography（HPLC） analysis, the magnetic imprinted polymers were used to solid-phase extract and detect HSA in urine samples successfully with the recoveries of 92.0-97.8%.3. A novel polydopamine-coated multi-template magnetic molecularly imprinted polymers（MMIPs） based on multi-walled carbon nanotubes（MWNTs） was prepared for rapid magnetic separation and enrichment of bisphenol A（BPA）, tetrabromobisphenol A（TBBPA） and tetrabromobisphenol S（TBBPS） in milk sample. The MMIPs were characterized with Fourier transform infrared spectra, thermogravimetric analysis, vibrating sample magnetometer, scanning electron microscopy and transmission electron microscopy in detail. The adsorption behavior of the MMIPs was studied and the results showed that the MMIPs exhibited specific selective adsorption toward BPA, TBBPA and TBBPS. The maximum adsorption capacity of the MMIPs for BPA, TBBPA and TBBPS was 52.08, 46.08 and 42.05 mg g^-1, respectively. Coupled with high performance liquid chromatography, the MMIPs were used to magnetic solid-phase extract and detect trace BBPA and TBBPS in milk sample successfully with the recoveries of 84.8- 95.0 %.4. In this study, a novel magnetic dummy molecularly imprinted polymers was prepared by using of multi-walled carbon nanotubes as the support materials, 2-amino-4-chlorophenol as the dummy template. The magnetic dummy molecularly imprinted polymers were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and vibrating sample magnetometer in detail. Saturation adsorption capacity for 4-chlorophenol was up to 54.3 mg g^-1 at 298 K, which is higher than that of the previous reported imprinted polymers. Coupled with high performance liquid chromatography, the magnetic dummy molecularly imprinted polymers were used to magnetic solid-phase extract and detect 4-chlorophenol in fish bile sample and river water sample successfully with the recoveries of 95.8- 98.9% and 96.6- 99.1%, respectively.