Construction And Application Of Electrochemical Sensors Based On Metal Organic Frame Materials

Metal-organic frameworks(MOFs),constructed by organic linkers and metal ions or clusters,have gained intensive attention and thus widely used molecular separation,catalysis,gas storage,drug delivery and biosensor due to their high porosity,tunable structures and flexible tailorability.In this paper,MOFs with large specific surface area and high porosity has been established an electrochemical biosensor for the detection of nitrite in foods.The main work is as follows:1.Cu-Co Prussian blue analogue(CuII3[CoIII(CN)6]2)/multi-walled carbon nanotubes(Cu-Co PBA/MWCNTs)composite was synthesized and then modified on the surface of glassy carbon electrode(GCE)to fabricate an electrochemical sensor for detection of nitrite.The morphology and composition of the fabricated nanomaterial were characterized by X-ray diffraction,energy dispersive X-ray spectroscopy,and scanning electron microscopy.Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior and mechanism of the fabricated biosensor.Experimental results showed that Cu-Co PBA/MWCNTs/GCE had excellent electrochemical activity towards nitrite.Under the optimal conditions,a wide linear range from 10 ? 400 ?M and 400 ? 2100 ?M and a detection limit of 0.5 ?M were found.Moreover,this sensor was employed to determine the concentration of nitrite in ham sausage and mustard samples,and showed excellent good anti-interference,stability,repeatability and satisfied recovery.2.Copper-based metal organic framework/gold-platinum alloy nanocomposite(CuMOF/Au@Pt)modified glassy carbon electrode was developed via a simple wet chemical synthesis method followed by the electrochemical deposition of gold platinum alloy nanoparticles on the surface of GCE.The morphological and component analysis of the prepared nanomaterials were carried out by Fourier transform infrared(FTIR)spectrum and scanning electron microscopy.Cyclic voltammetry and electrochemical impedance spectroscopy(EIS)were used to study the electrochemical behavior of the fabricated electrodes.Results showed that Cu-MOF/Au@Pt/GCE exhibited the excellent electrochemical performance toward nitrite due to the large specific surface area of Cu-MOF combined with excellent catalytic activity and sensitivity of Au@Pt alloy nanoparticles.Therefore,a sensitive electrochemical sensor for nitrite detection was established.Under the optimal conditions,the amperometric response indicated that Cu-MOF/Au@Pt/GCE can detect nitrite in a wide linear range of 0.1 ? 12200 ?M with a low detection limit of 72 n M.Moreover,Cu-MOF/Au@Pt/GCE was employed to determine the concentration of nitrite in ham sausage and mustard samples,and exhibited good repeatability,reproducibility,stability,anti-interference and food sample analysis capabilities.