Research On The Preparation And Application Of Modified Electrodes Based On Imidazole Ester Framework Material (ZIF-8) And Its Composites

Metal-organic frameworks(MOFs)are a new class of crystalline porous materials which are constructed by connecting metal ions with organic links.MOFs have unique properties including of great surface area,stable chemical properties,and adjustable pore sizes and functionalities,which have attracted enormous interests.Zeolitic imidazolate frameworks(ZIFs),an attractive subclass of MOFs,exhibit the facility of synthesis,great thermal,hydrothermal and chemical stabilities compared with most of other MOFs.They have shown great potential in gas storage,separation,chemical sensing,drug delivery and catalysis.Among ZIFs materials,ZIF-8 has been widely concerned.Recently,MOFs has emerged as one kind of promising materials for constructing electrochemical sensors.However,poor conductivity of MOFs largely restricts their application in the electrochemical sensing area.To enhance the electrical conductivity,the construction of conductive MOFs-based composites by introducing excellent conductive and electroactive materials into MOFs is an effective method.Moreover,the prepared MOFs-based sensor showed great reproducibility,stability and applicability in real samples detection.Herein,three ZIF-8-based modified electrodes were fabricated and their electrochemical characters were studied.The main works is concisely described as followed.1.An electrochemical sensor based on the Nafion/PANI/ZIF-8 modified electrode for the determination of DA was successfully fabricated.Combining the excellent electroconductive properties of PANI with the large surface area and chemical stabilities of ZIF-8,the Nafion/PANI/ZIF-8 modified glassy carbon electrode exhibit excellent electrocatalytic activity for highly sensitive and selective determination of DA.With the excellent features such as high selectivity and sensitivity,wide linear range,good reproducibility and excellent stability,the present sensor provides a new strategy for determination of DA in real samples.2.The RGO/ZIF-8 nanocomposite was successfully fabricated with reference to the good electrical conductivity and specific surface area of RGO.RGO was used as atemplate for the nucleation and growth of ZIF-8.The fabricated RGO/ZIF-8 sensor exhibited high sensitivity for the determination of DA,owing to the synergistic effect from highly electrical conductivity of RGO and porosity of ZIF-8,which promote the electron transfer and facilitate the mass transfer.RGO/ZIF-8/GCE showed improved sensitivity and selectivity for the determination of DA.Moreover,the prepared sensor showed great reproducibility,stability and applicability in real samples detection.3.Using methylene blue(MB)as an electron transfer mediator,RGO was used as a template for immobilizing ZIF-8 crystals encapsulated with methylene blue(MB@ZIF-8).The obtained MB@ZIF-8/RGO nanocomposite modified GCE as a novel electrochemical sensing platform has been used for the sensitive detection of rutin.The MB@ZIF-8/RGO nanocomposite exhibited better performance due to its large surface area,good conductivity and strong electrocatalytic.The MB@ZIF-8/RGO modified GCE exhibited good performance of high sensitivity,low detection limit,wide linear range for rutin detection.In addition,the proposed sensor also exhibited good stability,reproducibility and anti-interference ability.The modified electrode was further used to analyze rutin in tablet samples with satisfactory results.