Study Of Electrochemical Sensors Of Phenolic Active Ingredients Based On Metal-Organic Frameworks And Their Derived Materials Modified Electrode

Metal-organic frameworks（MOFs）are porous crystalline materials that use metals or metal ions as connecting nodes,and then use organic compounds to bridge to form porous polymers.It has been used of fields of catalysis,energy storage,separation and adsorption because of its surface area and porosity.In electrochemical sensing,MOFs have also recently been frequently used as electrode modification materials to improve the sensitivity and response signal of electrodes.Generally speaking,problems such as low electronic conductivity and poor hydrothermal stability of the original MOF are the reasons that hinder the performance of MOF-modified electrodes.Therefore,MOF is often compounded with other materials or MOF-derived materials are synthesized using MOF as a precursor.Electrode modification is performed to improve the performance of the electrode.This optimized material can fully improve the poor electrical conductivity of the original MOF and easily fall off from the electrode surface,so it can be well applied to the construction of electrochemical sensing platforms.In this paper,three electrochemical sensing platforms for the detection of compounds in aqueous solutions have been successfully built using MOF-based composites and MOF-based derivatives.Some of them are briefly described as follows:1.The Cu/Zn-ZIF was prepared by a traditional hydrothermal method,and polyvinylpyrrolidone（PVP）was added to control its surface morphology during the synthesis process,and then calcined at 800℃ at high temperature to obtain a nitrogen-containing carbon material BM@NS increased electron transfer rate.The relevant data of its surface morphology were obtained by SEM and XRD.The optimal electrode material was obtained by adjusting the ratio of metal ions during synthesis,and finally an electrochemical sensing platform for luteolin was successfully prepared.The sensor platform has a good detection effect on luteolin.Its working curve equation is:Ip（μA）=0.0571C（nM）-1.2913,the minimum detection limit is 15 nM,and it has been successfully used for the detection of luteolin in real samples.2.Aluminum-based MOFs:CAU-1 were synthesized using a traditional solvothermal method and electrodeposited on carboxylated multi-walled carbon nanotubes.The microscopic morphologies of CAU-1 and MWCNTs-COOH were characterized by SEM and XRD.The crystal data were tested,and XPS was used for CAU-1 to characterize its elemental composition.In the experiment,the test environment and various measurement parameters were optimized,and the working curve of the sensor was determined.Finally,the CAU-1/MWCNTs/GCE rutin electrochemical sensor was successfully constructed,and its working curve was Ip（μA）=0.0241C（nM）+0.416,its linear range was 1 nM-3000 nM,and the detection limit was 0.67 nM.3.A bimetallic NiCo-MOF was synthesized.Surfactant was added during the synthesis to tailor its surface morphology,and then it was pyrolyzed at 400℃ to obtain a magnetic carbon material NiO-Co₃O₄@CNTs（NiCo@CNTs）.The prepared NiCo@CNTs was electrodeposited on reduced graphene oxide to construct a new NiCo@CNTs/rGO/GCE dopamine electrochemical sensor,and the surface morphology of the electrode material was characterized by SEM.In the experiment,the electrochemical parameters when constructing the electrode were optimized first,then the experimental conditions were optimized,and the working curve of the working electrode was finally determined:Ip₁（μA）=0.0064C（nM）-0.6783;Ip₂（μA）=0.0013C（nM）+33.787 and the detection limit was 45 nM.Measurement of dopamine in real samples have also succeed.