Investigation Of Electrochemical Sensors Based On Conducting Polymer And Metal-organic Frameworks Composites

Sensing devices based on electrochemical methods have the advantages of low detection limits,portable devices,rapid response,and low cost.As one of the common methods of detection and analysis,sensing devices based on electrochemical method have aroused the interest and exploration of many scholars.Using different electrode modification materials to improve the analytical performance of sensors is an important research direction in the field of electrochemistry.Organic conducting polymers(OCPs)with π-conjugated electron structure along the main chain make it easier to load stably on the electrode surface,which bring more possibilities for electrochemical sensing.Different electrochemical properties can be generated by designing and preparing different polymer structures to meet the construction needs of electrochemical sensing platform.OCPs have good biocompatibility and excellent structural tunability,which are widely used in battery materials,photoelectric devices,separation and enrichment,energy storage and other fields.OCPs based composite materials are a class of electrode modification materials with great potential application because of their abundant functional group active sites,excellent charge transfer efficiency and superior electrochemical properties.On the other hand,the metal-organic frameworks(MOFs)are composed of metal center and organic ligand skeleton.Its ratio and morphology are adjustable,and it has high porosity and specific surface area,showing broad application prospects in many research fields.MOFs materials not only have the electronic structure of inorganic metal ions,but also have the functional characteristics of organic ligands that can introduce functional groups.Thus the sensor system can be designed and constructed from multiple dimensions.However,poor stability and weak electrical conductivity limit the application of MOFs based materials in the field of electrochemical sensing.However,poor stability and weak electrical conductivity limit the application of MOFs in the field of electrochemical sensing.To overcome these shortcomings,MOFs materials can be combined with other nanomaterials,and the composite conditions conducive to electrochemical signal transmission can be found,so that the stability,sensitivity,detection ability and other properties of the electrochemical sensor can be significantly enhanced,and the performance of the electrochemical sensor can be effectively improved.In this paper,electrochemical sensors for different purposes are constructed based on OCPs and MOFs composite materials,and the mechanism of the sensors is further explored.The specific work is as follows:1.The “Donor-Acceptor” type molecule,2,3-bis(4 ’-(diphenylamino)-[1,1’-biphenyl]-4-yl)fumaronitrile(TPATCN)was designed and prepared by using diphenyl fumaronitrile(trans-dicyanostilbene)as electron acceptor unit and triphenylamine as electron donor.Fumaronitrile acts as an intermediate nucleus with cis-trans isomerism to connect the external electron donor and thus the conducting polymer with high conjugation degree is obtained.As electrode modification material,TPATCN can effectively enhance the charge migration and improve the stability of the system.The electrochemical aptamer sensor for ATP detection showed good selectivity with a low detection limit of 0.018 p M,which proved that OCPs have wide application prospect in the fabrication of electrochemical aptamer sensor.2.Poly-Cz PAP/GCE was obtained by electrochemical polymerization of 9-(4-(10-phenylanthracen-9-yl)phenyl)-9H-carbazole(Cz PAP)on bare glassy carbon electrode(GCE).Carbazole based polymers have good electrical conductivity and abundant active sites,showing excellent catalytic activity for electrochemical oxidation of dopamine and acetaminophen,which can be used for simultaneous detection.The fabricated sensor exhibited a wide detection range of 0.5-250 μM.Moreover,the mechanism of the sensor platform is further explored by density functional theory(DFT).After a series of characterization evaluations,the sensor platform has been proved to have potential applications in human environmental monitoring and drug detection.3.Through one-step hydrothermal synthesis,copper organic skeleton(Cu BTC)was synthesized as the material substrate for electrode modification,and silver nanoparticles(Ag NPs)were added for encapsulation.The two were fixed on the graphene sheet,and Ag@Cu BTC/ERGO ternary composite was successfully constructed by electrochemical reduction.Orthogonal experiment was designed to optimize the dosage and finally applied to the electrochemical detection of hydroxychloroquine(HCQ).Ag@Cu BTC/ERGO composite has a multi-channel structure with large specific surface area and good electrical conductivity,which enhances the electrocatalytic performance of the sensor.Under the synergistic action of the ternary composite,the electrochemical sensor showed high stability with a low detection limit of 0.058 μM,and could be used for the detection of HCQ in human serum environment and pharmaceutic preparation.In summary,the electrode modification was designed based on the properties of the analytes to enhance the sensor performance in this work.The constructed electrochemical sensors for different types of analytes have provided new ideas for high-performance sensing platforms,which also promoted the development of electrochemical biosensing and drug analysis.