Syntheses Of Metal-organic Frameworks Based On Thiacalix[4]arene And Electrochemical Detection Of Chlorogenic Acid By Their Composites With Carbon Materials

With more and more attention paid to medical health care and food nutrition,chlorogenic acid has been widely researched because of its anti-diabetes,anti-oxidation and other activities.Therefore,it is very urgent to construct a rapid and sensitive detection method for chlorogenic acid.In this paper,different electrochemical sensors were constructed to detect chlorogenic acid effectively.Metal-organic frameworks（MOFs）have ordered structure,ultra-high porosity,outstanding thermal stability,and have been widely used in electrochemical detection.In this paper,three MOFs were synthesized,and mixed with different carbon materials to make composites for the detection of chlorogenic acid.In this paper,ligand（L）was synthesized based on thiacalix[4]arene,and three MOFs were synthesized under solvent-thermal conditions,namely[Co₂LCl₄]·2DMF（Co-L）,[Cd₂LCl₄]·0.5Et OH（Cd-L）,[Zn₂LCl₄]·2Et OH·DMF（Zn-L）.The three MOFs were characterized by PXRD,TGA,FT-IR and SEM,and their structures were determined by single crystal X-ray diffraction technique.Co-L and Cd-L were isostructual,in which four-coordinated cations were linked by L ligands along different directions to form a 2D structure.In Zn-L,ligands L were linked by four-coordinated Zn（Ⅱ）ions to form a two-dimensional structure.Co-L,Cd-L and Zn-L were mixed with RGO（reduced graphene oxide）,MWCNT（multi-walled carbon nanotubes）and MC（mesoporous carbon）in different proportions to optimize their electrocatalytic properties.The optimized electrochemical sensors were Co-L@RGO（1:1）/GCE,Cd-L@RGO（1:1）/GCE,Zn-L@MC（2:1）/GCE,and the chlorogenic acid was quantitatively measured under the best detection conditions.The experimental results demonstrated that all the sensors showed good electrocatalytic effects with limit of detection（LOD）of 0.0072μM,0.010μM and 0.014μM,and all sensors showed good anti-interference,stability and reproducibility.At the same time,they could also realize the detection of chlorogenic acid in honeysuckle with satisfactory recovery.