Preparation Of Metal Organic Frameworks Composition Materials And Their Applications In Electrochemical Sensors

Due to its unique advantages,electrochemical sensor has been widely applied in analytical chemistry,in which the modified material is a key to determine the resulted electrochemical performance.Metal organic frameworks（MOFs）,with uniform porediameter,diverse structures,big specific surface and controlled properties,have showed huge application protential in electrochemical sensing field.However,poor conductivity of MOFs seriously restricts their practical applications in electrochemistry.Therefore,in this thesis,some conductive species such as carbon materials and metal nanoparticles are compounded with selected MOFs.And as a result,several electrochemical sensors with excellent electrochemical properties for sensitive detection of some medicine molecules and biomolecules have been prepared and their applications in real sample analysis have been studied too.The thesis mainly includes three parts as follows:1.ZIF-67 with cubic morphology was at first synthesized at room temperature using cobalt ion as metal source and 2-methylimidazole as organic ligand.And then it was ultrasonically mixed with carboxylate functionalized multi-walled carbon nanotubes（MWCNT-COOH）with excellent electrical conductivity and Nafion with good adhesion to prepare a uniform composite.At last,a modified electrode ZIF-67/MWCNT-COOH/Nafion/GCE was constructed by drip-coating the composite on the glassy carbon electrode（GCE）.The prepared modified electrode not only showed good conductivity but also delivered excellent electrocatalytic activity toward the the redox reactions of acetaminophen（AMP）and 4-aminophenol（4-AP）.The developed method has been successfully used to determine rapidly and sensitively these two analytes in Yellow water and Paracetamol tablets with wide linear ranges（0.2 to 200μM for 4-AP,0.1～20,20～100μM for AMP）and low detection limits（0.01μM for 4-AP and 0.07μM for AMP,S/N=3）.2.A novel electrochemical sensor was constructed for the highly sensitive detection of riboflavin（RF）using pre-prepared bimetallic Co/Fe MOFs（Co/Fe-MOF-74）and Au nanoparticles decorated multiwalled carbon nanotubes（AuNPs-MWCNTs）as modifing materials.Based the synergistic effect of these two materials,the developed sensor showed a high electrocatalytic activity for RF.It could be employed to detect RF content in Vitamin B₂ tablets,the linear ranges were 0.05～10μM and10～40μM,and detection limit was 8.7 nM.3.Aβ-CD-MOF was at first synthesized fromβ-cyclodextrin（β-CD）and potassium hydroxide（KOH）.And then by exploiting MoS₂ nanosheets and the composite of theβ-CD-MOF and acyl chloride-functionalized MWCNTs（a-MWCNTs）respectively as modifying materials,an electrochemical sensor MoS₂/β-CD-MOF/a-MWCNTs/GCE with sensitive responses for guanine（G）and adenine（A）was fabricated by a layer-by-layer modification process.The sensor could be used for separate and simultaneous determinations of G and A,the linear ranges were respectively 2～120μM for G and 8～200μM for A and the detection limits were respectively 0.23μM for G and 0.91μM for A.In addition,the developed method was also used to detect the contents of G and A in acid denatured Herring sperm DNA with a satisfactory result.