| Molecular imprinting technique?MIT? refers to the preparation of a polymer which has a specific selectivity of a particular kind of template molecule?target molecule/ molecular imprinting?,it's often described as a technology of making a molecular lock to a molecular key.MIT developed rapidly on account of its three advantages: structure-activity pre-determined characteristics of structure-activity,specific identifiability and extensive practicability.The development and application of molecularly imprinted polymeric?MIP? membranes have been one of the most attracting topic of modern and contemporary study of molecular imprinting. MIP membrane is a kind of synthetic membrane of high selectivity and stability, while electrochemical sensor could is easy to design,high selectivity,good sensitivity and high speed, low cost, easy to be operated and automation and miniaturization.Therefore it is of great significance to study MIP membrane as an element of recognition to prepare electrochemical sensors and biosensors.In this thesis,we are trying to combine nano materials and modern electrochemical technology together to prepare successfully a series of molecularly imprinted matrix as the sensitive element of new electrochemical sensors.We also researched the characteristics of MIP membrane by the technology of DPV, CV, UV,IR, SEM, EIS.The main points of this thesis were summarized as follows:1?With Quercetin?Qu? as template molecule and Pyrrole?Py? as functional monomer, Fe@Au nanoparticles are self-assembled on multi-walled carbon nanotubes,and molecularly imprinted polymer which has specific selectivity on Qu is prepared.And it is characterized with electrochemical impedance spectroscopy?EIS?,differential pulse voltammetry?DPV?,cyclic voltammetry?CV? and ultraviolet spectrum?UV?.As the existence of a variety of nanoparticles,it enhances the electron transfer rate of electronic reaction,and the sensitivity of imprinting electrodes is improved due to its excellent chemical stability.When the concentration of Qu iswithin the scope of 1.0×10-9-5.0×10-6molL-1, the peak current of its detection object keeps benign linear relationship with logarithm of the concentration,and the linear regression equation is I??A?=1.371lgC +9.635(C:molL-1). Phase relationship is0.9982,and the lower limit is 0.3nmolL-1?S/N =3?. The molecularly imprinted sensor is of high sensitivity, strong selectivity and good stability, and the actual sample of flos sophorae is tested with it.2.Applied the use of electrical aggregation method, sol-gel molecular imprinted films which has specific recognition sites on 2,4-D is prepared on the surface of glassy carbon electrode modified by multi-walled carbon nanotubes with scattered chitosan.And it is characterized with CV, EIS, DPV and SEM. The selectivity,stability and repeatability of molecularly imprinted sensor are studied and discussed.When the concentration of 2,4-D is within the scope of 1.0×10-9-1.0×10-5 molL-1,the probe molecule current keeps benign linear relationship with negative logarithm of the concentration,and the linear regression equation is I??A?=-0.979lgC+10.533(molL-1).Phase relationship is r=0.9957, and the detection limit is 0.48 nmolL-1.This sensor can be used to detect the contents of 2,4-D on the grass' s leaves and the apple's epidermis, whose results are satisfactory.3?This part of the thesis using molecular imprinting technique,SY as the template molecules, acrylamide?AM? as functional monomer, using polymerization method successfully constructed a electrochemical sensor with which SY has been detected on the glassy carbon electrode surface modified with a multi-walled carbon nanotubes.Based on SEM, DPV, CV, UV, and PEIS was characterized by the sensor.The concentrations ranging from 5×10-7 to 1×10-5 molL-1 was obtained with the linear regression equation I??A?=1.552C+8.778×10-7( C:?molL-1).The detection limit of the sensor was 0.18?molL-1?S/N=3?.This method has good selectivity, high sensitivity, and good reproducibility, providing a simple and controllable method to detect SY. |
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