The Preparation And Electrochemical Study Of Novel Surface Molecularly Imprinted Polymers

Molecular imprinted polymers（MIP）,as artificial receptors,has several advantages,including durability in acidic/alkaline condition,high stability and sensitivity,and convenience for preparation.This has made it widely used in several feilds,such as membrane separation,solid phase extraction,and sensing technology.The electrochemical sensor has attracted researchers attention due to its advantages,including high sensitivity,excellent selectivity,low cost and convenience for operation.As a sensitive recognition element,the molecular imprinted polymers can significantly improve the selectivity of electrochemical sensors,so that the monitoring and analysis of complex samples can be realized.Through the combination of nanomaterials and molecular imprinted polymers,the performance of molecular imprinting electrochemical sensors can be further improved and the practicability is enhanced.In this paper,a molecular imprinted polymer membrane based on nano-material is prepared and applied in the study of electrochemical sensors.Practical works are as follows:1.A novel electrochemical sensor was developed based on molecularly imprinted polymerandmultiwalledcarbonnanotube（MWCNT）waspreparedby electropolymerization method.The MIP film was prepared on the surface of MWCNT modified electrode by using o-phenylenediamine as a functional monomer and4-aminosalicylic acid as a template molecule.The morphology MIP/MWCNT was characterized by scanning electron microscopy（SEM）and its electrochemical performance was characterized by cyclic voltammetry（CV）method.In this paper,we have investigate the electrochemical performance of 4-aminosalicylic acids on different kinds of modified electrodes and the selectivity of the sensor to the analyte and its structural analogues.Owing to the introduction of carbon nanotubes and MIP,the specific surface area of the electrode,the sensitivity and selectivity of the electrochemical sensor was improved.With a linear response range of 0.2μmol/L-400μmol/L and a detection limit of 0.024μmol/L（S/N=3）,the sensor exhibits a good selectivity,stability and repeatability in determine4-aminosalicylic acid.Further more,the sensor has been successfully applied to detect4-aminosalicylic in human urine samples and sodium 4-aminosalicylate with satisfied recovery（93.4%-104.7%）.2.Copper oxide nanoparticles were successfully prepared by hydrothermal method using Cu（NO₃）₂·H₂O as copper source.A novel salicylic acid electrochemical sensor was developed based on molecularly imprinted polymer and copper oxide nanoparticles（CuONPs）.The surface morphology and electrochemical properties of the molecularly imprinted polymer membrane were characterized by scanning electron microscopy and cyclic voltammetry method,respectively.The oxidation mechanism of salicylic acid was studied by cyclic voltammetry method.The selectivity of the sensor was studied in detail.The sensor has a linear response range of 0.7μmol/L-600μmol/L with a detection limit of0.046μmol/L（S/N=3）in determine salicylic acid.The sensor was further used to determine the content of salicylic acid in the urine sample and acne tincture with the recoveries of 92.6%to 106.4%.3.Carbon spheres（CSs）were prepared by hydrothermal method using glucose as carbon source.Molecularly imprinted polymer was prepared by electropolymerization method on the surface of CSs modified glassy carbon electrode with acrylamide as a functional monomer and folic acid as a template molecule.The electrochemical behavior of CSs/MIPmodifiedelectrodewasinvestigatedbydifferentialpulse voltammetry（DPV）method.The results showed that CSs/MIP has a good specific adsorbability for folic acid.The sensor has a linear response range of 0.7μmol/L-800μmol/L for folic acid with a detection limit of 0.031μmol/L（S/N=3）.