Research On Electrochemical Sensor Based On Conductive Metal-Organic Framework And Its Application In Environmental Hormone Detection

Metal-Organic Frameworks（MOFs）are porous crystalline materials,which are mainly formed by coordination between organic and inorganic（metal ions）units.MOFs are wide utilized within the fields of sensing,drug delivery,gas storage and separation,because of their massive specific surface area,low density,adjustable pore size and high porousness.However,due to the inherently poor electron transfer capability of most MOFs,their development in the electrochemical field is limited.In recent years,the development of conductive MOFs has extremely promoted the application of MOFs in the domain of electrochemical sensors,but most conductive MOFs do not have selectivity to target molecules.Therefore,synthesizing new functional materials on MOFs to improve their selectivity has important research significance.In this paper,conducting MOFs and molecularly imprinted polymers were used to construct molecularly imprinted electrochemical sensors with good selectivity,electrochemical aptamer sensors were prepared on the basis of conducting MOFs for highly selective detection of environmental hormones.The precise work is as follows:1.A novel conductive metal-organic framework and molecularly imprinted polyionic liquid composite（CMOF-MIPIL）for high sensitivity detection of bisphenol A（BPA）was prepared.The performances of the prepared Ni-based CMOF were studied.The results proved that Ni₃（HITP）₂has the highest electrical conductivity and the largest effective surface area.CMOF-MIPIL was prepared with Ni₃（HITP）₂ as carrier,BPA as template,ionic liquid as monomer and crosslinking agent.Under the best conditions,the detection limit of CMOF-MIPIL sensor for BPA is 4.0 nmol/L,that encompasses a sensible linear relationship within vary of 0.005-5.0μmol/L.Compared with MIPIL,Ni₃（HITP）₂ based sensors and CMOF-NIPIL sensors,its performance in detecting BPA is superior,due to its excellent conductivity and specific recognition sites.In addition,The CMOF-MIPIL sensor is suitable for the detection of BPA in environmental water samples,plastic bottles and fresh milk samples,showing good selectivity for BPA,and the recovery rate was between 95.3%-104.0%.2.Researched an aptamer sensor based on a composite of conductive MOF and gold nanoparticles for the detection of carbendazim（CBZ）.Conductive MOF（Cu₃（HHTP）₂）was synthesized by solvothermal method,and Au NPs were synthesized on Cu₃（HHTP）₂ by Na BH₄ one-step reduction method to form Cu₃（HHTP）₂-Au NPs composite material.The aptamer modified with-SH is fixed on the electrode surface by the Au-S bond to construct an electrochemical aptamer sensor.The detection limit of Cu₃（HHTP）₂-Au NPs aptamer sensor for CBZ is 3.0×10^-14 mol/L（S/N=3）,showing a sensible linear relationship within vary of 10^-13-10^-8 mol/L.The Cu₃（HHTP）₂-Au NPs aptamer sensor is suitable for the detection of CBZ in real samples and is specific for CBZ.3.Constructed an electrochemical sensor based on bimetallic conductive MOF magnetic molecularly imprinted poly ionic liquid for the detection of diphenylamine（DPA）.Synthesize Co Ni-MOF on Fe₃O₄ to form Fe₃O₄@Co Ni-MOF composite material,using composite material as carrier,DPA as template molecule,ionic liquids as monomer and crosslinking agent respectively,to synthesize magnetic molecularly imprinted polyionic liquid Fe₃O₄@Co Ni-MOF-MIPIL.The prepared Fe₃O₄@Co Ni-MOF-MIPIL sensor is selective for DPA detection with a detection limit of 3.0×10^-12 mol/L（S/N=3）,and a good linear relationship within the concentration range of10^-5-10.0μmol/L.The Fe₃O₄@Co Ni-MOF-MIPIL sensor was applied to environmental sample detection,and also the recovery rate was92.2%-103.1%.