Preparation And Application Of Electrochemical Sensor Based On Metal Organic Framework Pyrolysis Derivatives

Object:Electrochemical sensors have the advantages of rapid detection,low cost,simple operation,and easy miniaturization.They are widely concerned by researchers.Since its birth,electrochemical sensors have achieved good development.However,the main problems that restrict the development of electrochemical sensors are that the sensitivity still needs to be improved,the selectivity is poor,the reproducibility is weak,and the material modification is not solid.This paper provides some solutions for solving the above bottleneck problems.Methods:A variety of structure-controllable MOFs were prepared by solvothermal method.Several different MOF pyrolysis derivatives were successfully prepared by high-temperature carbonization.A variety of thermoelectric derivatives based on MOFs were constructed.Chemical sensors improve the selectivity,reproducibility and stability of electrochemical sensors by introducing molecularly imprinted polymers,ratiometric electrochemical and self-cleaning electrode strategies,and magnetic nanomaterial modification strategies.Results:In this paper,based on the advantages of excellent electrical conductivity,large specific surface area and high pore volume of MOFs pyrolysis derivatives,three new electrochemical sensors were constructed for small molecule drugs and human neurotransmitters in actual samples.And determination of the content of endogenous substances.The specific work is summarized as follows:?1?A novel molecularly imprinted electrochemical sensor based on MOF pyrolysis-derived porous carbon for determination of lidocaineThe work describes a hybrid electrochemical sensor for highly sensitive detection of the anesthetic lidocaine?LID?.Porous carbon?PC?was synthesized from an isoreticular metal-organic framework-8?IRMOF-8?and drop cast onto a glassy carbon electrode?GCE?.A layer of a molecularly imprinted polymer?MIP?layer was then fabricated in situ on the modified GCE by electro-polymerization,with LID acting as the template and resorcinol as the functional monomer.We optimized the ratio of functional monomer and template molecules used and pH conditions in electropolymerization.Scanning electron microscope?SEM?,energy dispersive spectroscopy?EDS?,X-ray photoelectron spectroscopy?XPS?,Raman spectroscopy,BET were used for characterized the surface morphology and composition of the modified materials.Cyclic voltammetry?CV?and electrochemical impedance spectroscopy?EIS?were used to characterize and evaluate the sensor's electrochemical properties.Hexacyanoferrate is used as an electrochemical probe.The electrical signal?typically acquired at 0.335 V vs.SCE?increases linearly in the 0.2 pM to 8 nM LID concentration range,with a remarkable 67 fM detection limit?at an S/N ratio of 3?.The sensor is stable and selective.Eventually,rapid and accurate detection of LID in spiked real samples was successfully realized.?2?A novel ratiometric electrochemical sensor based on MOF pyrolysis derivatives for determination of adrenaline,serotonin and tryptophanTo address these challenges,we developed a facile electrochemical method,which integrated ratiometric strategy with self-cleaning electrode.In the novel sensing system,the self-cleaning electrode was realized via forming a hydrophobic layer on carbonized ZIF-67@ZIF-8?cZIF?by PDMS precursor vaporization.As for ratiometry,it is worth to mention that the measurements were conducted by adding interior reference?methylene blue,MB?directly into electrolyte solution,which is more facile and flexible to operate compared with conventional ones.Sensing performance of the self-cleaning electrode as well as the newly established ratiometric strategy was explored fully and it turned out that PDMS@cZIF nanocomposites provided decent electrocatalytic ability,superhydrophobic property and stability.Furthermore,ratiometric strategy significantly elevated the robustness and reproducibility of electrochemical sensing.Simultaneous detection of Adr,5-HT and Trp was performed under the optimum experimental conditions with wide linear ranges and low detection limits.Finally,the original R-ECS was successfully applied for monitoring the three target molecules in biological samples.?3?Simultaneous voltammetric determination of dopamine and uric acid based on MOF pyrolysis-derived Fe₃O₄@C magnetic nanoparticles modified electrochemical sensorAn electrochemical sensor for simultaneous determination of dopamine?DA?and uric acid?UA?was constructed.The sensor was obtained by attracting Fe-MOF derived Fe₃O₄@C nanoparticles on the surface of the magnetic glassy carbon electrode?mGCE?.The morphology and elements of the materials were characterized by SEM and EDS,and the properties of different modified electrodes were studied via CV and DPV.DA and UA were simultaneously determined by DPV,and the potenials of oxidation peaks are0.184 V and 0.328 V,respectively?vs.SCE?.After detailed experimental optimization,the DA calibration curve is linear from 0.1 to 150?M,and UA is from 0.5 to 135?M,with detection limits of 0.04?M and0.17 mM?S/N=3?.Finally,Fe₃O₄@C/mGCE was successfully applied to the quantitative analysis of DA and UA in rat serum and UA in human urine samples.Conclusion:Three novel electrochemical electrochemical sensors based on MOFs pyrolysis derivatives have been successfully constructed in this study.Combined with molecular imprinting technology,the selectivity and anti-interference of the sensor in complex matrix can be significantly improved.Ratiometric electrochemical sensing and self-cleaning electrode strategies significantly reduce the inherent systematic and accidental errors from environmental and personal operating factors and non-specific adsorption of electrode surfaces,significantly enhancing the accuracy,reliability,reproducibility and stability of the prepared sensors.The magnetic electrode modification strategy can avoid the problem of weak modification of the sensor dispensing material and increase the sensitivity,stability and reliability of the sensor.