Preparation Of Several Nano-composite Materials And Their Applications In The Field Of Sensor

Nano conductive material owns large surface area, specific surface energy and surface charge density due to special physical and chemical properties, for example, small size effect, surface effect, quantum size effect, low resistivity; and is employed as modifying material and play a significant role in enhancing sensing sensitivity. Molecularly imprinted polymer has huge practicality in quantitative and qualitative analysis for single component of mixture by possessing predetermined selectivity. As modifying material for sensing platform, it can improve the selective response; extend the application of sensor from pure sample to complicated sample; and simplify the pre-process of sample. Hence, based on the features of nano conductive material and MIP, this work established four kinds of novel electrochemical sensors by using nano composite as modifying material, metronidazole(MNZ) and dopamine(DA) as model analytes. The main tasks are as follow:(1) Preparation and application of metronidazole electrochemical sensor based on multi-walled carbon nanotubes(MWCNTs) and MIP: MWCNTs-modified glass carbon electrode(MWCNT/GCE) was prepared by drop coating the suspension of MWCNTs on electrode surface and evaporation of the solvent under infrared lamp. Electropolymerization of functional monomer in the presence of MNZ on the electrode surface was realized by cyclic voltammetry(CV). After that, the MWCNT/GCE bearing the electropolymerized poly-DA film was immersed in diluted H2SO4 to extract embedded MNZ by CV. Then the sensor modified with composites of MWCNTs and MNZ-imprinted MIP(MNZ-MIP/MWCNT/GCE) was obtained. A series of parameters are investigated and optimized during sensor preparation. The morphology characterization by SEM displayed the successful deposition of polymeric layer on MWCNTs surface. A series of electrochemical sensing properties were explored by CV. The established sensor is completely reusable and maintains excellent stability. These predominant properties enlist this hybrid electrode to exhibit high reliability for analyzing real samples and detection of MNZ directly in pharmaceutical dosage form and in fish tissue is successfully.(2) Preparation and application of metronidazole electrochemical sensor based on nano porous gold leaf(NPGL) and MIP: NPGL was prepared by selectively dealloying Ag from Ag/Au alloy leaves and was carefully affixed to gole electrode(GE) surface via direct physical adsorption. The NPGL-modified GE(NPGL/GE) was dried under infrared lamp. Electro-polymerization of MIPs in the presence of MNZ on the electrode surface was realized by CV. The NPGL/GE bearing the polymer film was immersed in H2SO4 to extract embedded MNZ by CV. Then the sensor modified with composites of NPGL and MNZ-imprinted MIP(MNZ-MIP/NPGL/GE) was obtained. A series of parameters are investigated and optimized during sensor preparation. The morphology characterization by SEM displayed the successful deposition of polymeric layer on NPGL surface. A series of electrochemical sensing properties were explored by CV. The established sensor is completely reusable and maintains excellent stability. These predominant properties enlist this hybrid electrode to exhibit high reliability for analyzing real samples and detection of MNZ directly in pharmaceutical dosage form and in fish tissue is successfully.(3) Preparation and application of metronidazole electrochemical sensor based on hollow nickel nanospheres(HNNSs) and MIP: a Ni-Cu alloy film was electrodeposited onto a bare GE under a constant potential of-0.75 V. Afterwards, selective dissolution of Cu from the deposited Ni-Cu film was conducted in the same solution by applying an anodic potential of 0.2 V; the developed nanoporous nickel gold electrode was denoted as HNNS/GE. Electropolymerization for preparing MIP was performed by CV. After that, the embedded MNZ were extracted by cyclic voltammetric scanning in NaOH solution. Then the sensor modified with composites of HNNS and MNZ-imprinted MIP(MNZ-MIP/HNNS/GE) was obtained. The morphology characterization by SEM displayed the successful deposition of polymeric layer on HNNS surface. A series of electrochemical sensing properties were explored by CV and electrochemical impedance spectroscopy(EIS). The established sensor is completely reusable and maintains excellent stability. These predominant properties enlist this hybrid electrode to exhibit high reliability for analyzing real samples and detection of MNZ directly in pharmaceutical dosage form and in fish tissue is successfully.(4) Preparation and application of dopamine electrochemical sensor based on hollow nickel nanospheres(HNNSs) and MIP: a Ni-Cu alloy film was electrodeposited onto a bare GE under a constant potential of-0.75 V. Afterwards, selective dissolution of Cu from the deposited Ni-Cu film was conducted in the same solution by applying an anodic potential of 0.2 V; the developed nanoporous nickel gold electrode was denoted as HNNS/GE. Electropolymerization for preparing MIP was performed by CV. After that, the embedded DA molecules were extracted by cyclic voltammetric scanning in NaOH solution. Then the sensor modified with composites of HNNS and DA-imprinted MIP(DA-MIP/HNNS/GE) was obtained. The morphology characterization by SEM displayed the successful deposition of polymeric layer on HNNS surface. A series of electrochemical sensing properties were explored by CV and EIS. The established sensor is completely reusable and maintains excellent stability. These predominant properties enlist this hybrid electrode to exhibit high reliability for analyzing real samples and detection of DA directly in blood sample is successfully.