Electrochemical Sensors Based On Molecularly Imprinted Nanoarrays

Electrochemical sensors are a class of devices,using electrochemical principles correlates changes in the concentration of a component under test with electrochemical signals to provide real-time information on the chemical components of the system being tested.When the electrochemical method is used to detect the measured object,the process is relatively simple,the detection speed is fast,the sensitivity is high,and the cost is low,so this has become a research hotspot in this field.Among them,the molecularly imprinted electrochemical sensor is one of electrochemical sensing.The advantages of molecularly imprinted sensor sensors are outstanding compared to conventional electrochemical sensors.Not only has high sensitivity,but also has specific selectivity.Flexible carbon cloth and three-dimensional bio-carbon derived from kenaf was used as electrode substrate,by immobilizing a metal organic framework material and a metal nanocomposite derived therefrom.Preparation of a molecularly imprinted electrochemical sensor,and applied to the practical application of ascorbic acid and dopamine.Compared with traditional electrochemical sensors,this molecularly imprinted electrochemical sensor greatly improved the selectivity and repeatability of the electrode.The specific work includes the following three aspects:1.A molecularly imprinted electrochemical sensor based on the organometallic framework ZIF-67 was constructed and used to detect ascorbic acid(AA).The molecular imprinting sensor is simple and quick to synthesize,and the imprinted polymer is electrodeposited by cyclic voltammetry,and the template molecule is eluted by soaking with ultrapure water.The sensor is prepared by using ascorbic acid(AA)as a template molecule,o-phenylenediamine(O-PD)as a functional monomer and a linker,and electropolymerization based on the organometallic framework ZIF-67/carbon cloth to form a molecule imprinted polymer integrated electrode with specific selectivity for ascorbic acid.ZIF-67 is immobilized on carbon cloth by in-situ polymerization at room temperature.Template molecules are added during the imprinting process,the elution of the template molecule produces a binding site on the molecularly imprinted polymer that is complementary to the shape and size of the template molecule,thus resulting in specific selectivity for ascorbic acid.This work also explored the electrochemical performance of the molecularly imprinted electrochemical sensor,as well as some electrochemical characterization.The molecularly imprinted sensor exhibits high sensitivity,The sensitivity can reach 959.9?A/mM-1cm-2,the detection limit is 0.019?M,and the concentration range of AA is 0.057 ?M-11.4 0mM.2.In this work,a Cu-Co-ZIF derived CuCo2O4 nanocomposite based on three-dimensional porous carbon was prepared as a catalyst to construct a molecularly imprinted electrochemical sensor for the detection of dopamine(DA).Firstly,Cu-Co-ZIF was synthesized at room temperature by in-situ polymerization,then the nanocomposite CuCo2O4 was obtained by high-temperature carbonization.Finally,the molecularly imprinted polymer was imprinted by potentiostatic electrodeposition to obtain the target material nMIPs/CuCo2O4/3D-KSC.Among them,the molecularly imprinted polymer was prepared by using dopamine(DA)as a template molecule,chitosan(CS)as a linking agent and a functional monomer.At the same time,we explored the morphology and composition of the composite by using various characterization methods,then studied its properties through different electrochemical tests.The experimental results showed that the nMIPs/CuCo2O4/3D-KSC integrated electrode exhibited excellent anti-interference ability,high sensitivity,low detection limit and wide detection range.This work proved the molecularly imprinted dopamine electrochemical sensor had excellent electrochemical performance,and the sensitivity for dopamine detection was 720.8 ?AmM-1cm-2,the detection range was 0.51?M?1.95 mM,and the detection limit was 0.16?M.3.A novel dopamine(DA)-imprinted chitosan(nMIP)/ZnONPs@carbon(C)/three-dimensional kenaf stem-derived macroporous carbon(3D-KSC)integrated electrode was developed for electrochemical sensing DA.Here,zeolite imidazole framework-8(ZIF-8)was firstly grown on the 3D-KSC,then ZnONPs@C/3D-KSC was obtained by carbonizing the ZIF-8/3D-KSC under nitrogen atmosphere.Finally,the nMIP/ZnONPs@C/3D-KSC was prepared by electrodepositing chitosan on ZnONPs@C/3D-KSC in the presence of DA.Scanning electron microscopy,X-ray powder diffraction,energy dispersive X-ray spectroscopy,X-ray photoelectron spectroscopy,electrochemical techniques,etc,were used to investigate the nMIP/ZnO NPs@C/3D-KSC.It was found that the ZnONPs@C was porous nanospheres and uniformly arrayed on the 3D-KSC surface to form a monolayer film.The diameter of nanospheres was approximately 500?600 nm,and the nanospheres were composed of ZnONPs embedded in porous carbon.A layer of chitosan with the thickness of about 10 nm was covered on the ZnONPs@C nanospheres.The nMIP/ZnO NPs@C/3D-KSC integrated electrode exhibited better selectivity for DA.The linear range for detection of DA was 0.039 ?M?152 ?M,the detection limit was 0.012 ?M,and the sensitivity was 757?AmM-1cm-2.The nMIP/ZstabilitynONPs@C/3D-KSC integrated electrode also showed better selectivity and higher stability.