Preparation Of Molecularly Imprinted Complex Membranes And Applications In Pharmaceutical Analysis

Molecularly imprinted membrane（MIM）made by combining molecular imprinting technology and membrane separation technology has the conjunct advantages of molecular imprinting technology and membrane separation technology.Compared with ordinary separation membranes,molecularly imprinted membranes have the characteristics of high selectivity to specific molecules,strong molecular recognition performance and high retention rate of imprinted holes.The electrochemical sensor has the advantages of low price,simple design,easy miniaturization,high sensitivity,etc.The molecularly imprinted membrane is used as a sensitive identification component in construction of an electrochemical sensor,which can obviously improve the selectivity of the electrochemical sensor,which can effectively achieve detection of complex samples analysis.Carbon nanomaterials have been widely used in the construction of electrochemical sensors due to their high specific surface area,high electrocatalytic activity and fast electron transfer efficiency.The electrochemical response of the analyte can be greatly improved by using carbon nanomaterials as the support material to construct the electrochemical sensor.The molecularly imprinted composite membrane prepared by carbon nanomaterials supporting the molecularly imprinted material can not only effectively amplify the response signal of the electrochemical sensor,but also improve the anti-interference ability of the sensor.In this paper,three molecularly imprinted composite membranes were prepared by electrochemical polymerization based on carbon nanomaterials and molecularly imprinted polymer materials,and were applied to the determination of flavonoid content and drug concentration in biological samples.The specific research content is as follows:1.A molecularly imprinted electrochemical sensor of genistein was constructed.The molecularly imprinted polymer membrane was prepared on the surface of carbon nanotube modified electrode by using carbazole as functional monomer and genistein as template molecule.The electrode materials were characterized by scanning electron microscopy and cyclic voltammetry.The electrochemical behavior of genistein on different modified electrodes was investigated.The oxidation mechanism of genistein was studied by cyclic voltammetry.The selectivity of the sensor was mainly studied.The results show that the carbon nanotubes increase the specific surface area of the electrode and improve the conductivity of the electrode.The molecularly imprinted polymer improves the selectivity of the sensor,thus greatly improving the detection performance of the sensor.The experimental results show that the linear range of the sensor is 0.02μmol L^-17μmol L^-1,the detection limit is 0.006μmol L^-1（S/N=3）,and was applied in the determination of genistein in the actual samples of genistein tablets and urine samples.2.A rutin molecularly imprinted electrochemical sensor was constructed based on a composite of carbon nanotubes and reduced graphene oxide（RGO-CNTs）and molecularly imprinted polymers（MIPs）.RGO-CNTs were prepared by hydrothermal synthesis method.Molecularly imprinted polymer membranes were prepared on the surface of the RGO-CNTs modified electrode using p-phenylenediamine（PPD）as functional monomer and rutin as template molecule.The electrochemical behavior of rutin on different modified electrodes was investigated.The oxidation mechanism of rutin and the selectivity of the sensor were studied.The results show that the three-dimensional RGO-CNTs composite has the advantages of large specific surface area,high catalytic activity and good electrical conductivity,and the introduction of molecularly imprinted polymer improves the sensitivity of the sensor and increases the electrochemical response of rutin by increasing the recognition site of rutin on the electrode.The linear range of the sensor is 0.02μmol L^-17μmol L^-1 and 7μmol L^-1400μmol L^-1,the detection limit is 0.006μmol L^-1（S/N=3）,so the sensor can selectively identify rutin,has good anti-interference ability,and is successfully applied in determination of rutin in rutin tablets and urine samples.3.A molecularly imprinted electrochemical sensor for simultaneous determination of puerarin and rutin was constructed.The nitrogen-doped carbon nano-frame structure（Fe-NCNFs）decorated by iron nanoparticles（Fe-NPs）was synthesized by chemical blowing process and tube furnace calcination method.The chitosan was used as dispersant of Fe-NCNFs to modify the glassy carbon electrode.Molecularly imprinted polymer membranes（MIPs）were prepared by cyclic voltammetry on the Fe-NCNFs modified glassy carbon electrode with benzpyrole-6-carboxylic acid as the functional monomer and puerarin as the template molecule.The electrochemical behavior of puerarin and rutin on different modified electrodes was studied.Fe-NCNFs has a large specific surface area,and enhanced adsorption to puerarin and rutin,which increases the electrochemical response puerarin and rutin,and the molecularly imprinted polymer improves the selectivity of the sensor.When the sensor detects puerarin and rutin simultaneously,the linear range of puerarin is0.07μmol L^-140μmol L^-1,and the detection limit is 0.008μmol L^-1（S/N=3）.The linear range of rutin was 0.07μmol L^-17μmol L^-1,and the detection limit was 0.005μmol L^-1（S/N=3）.The sensor was successfully used to determine the content of puerarin and rutin in Xinkeshu capsules.