Fabrication Of Novel Metal-organic Frame Composites And Their Applications In Electrochemical Sensors

In recent years,electrochemical sensors have been gradually used more and more in the field of analytical chemistry,due to their low cost,high accuracy and simple experimental operation,and have been used in the detection of food milk,human serum and other real samples.Focusing on the research heat of nano-materials and the special properties of metal-organic framework materials,new metal-organic framework composites are expected to improve the electrochemical detection performance of electrochemical sensors.In this paper,nano-materials of metal-organic frame materials were used to construct novel electrochemical sensors based on metal-organic frame composites to detect the possible harmful substances such as afraxin B₁in food and glucose in human serum samples.1.A novel aflatoxin B1 electrochemical aptasensor based on in situ synthesized palladium nanoparticles supported on iron porphyrin metal organic framework as signal amplifiers.In this chapter,zirconium chloride as the internal structure and iron porphyrin as the external structure was used to synthesize spindle-like metal-organic framework material（PCN-223-Fe）.Then,palladium nanoparticles（Pd NPs）were successfully grown on the surface of PCN-223-Fe by in-situ synthesis to obtained Pd NPs/PCN-223-Fe composites.PCN-223-Fe and PDNPs/PCN-223-Fe composites were characterized by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）and X-ray diffraction（XRD）.Subsequently,the complex was integrated with streptavidin（SA）to produce SA/PDNPs/PCN-223-Fe signal probes,and the results showed that the signal probes had very good catalytic performance for oxygen.First,the gold electrode surface was pretreated,and the gold electrode was combined with the end of c DNA to form a stable Au-S bond,which paved the way for the hybridization between DNA.The aptamer end on the gold electrode surface could specifically bind with SA/PDNPs/PCN-223-Fe signal probe.Finally,in oxygen saturated solution,the aptamer end on the gold electrode surface could specifically bind with SA/PDNPs/PCN-223-Fe signal probe.Differential pulse voltammetry（DPV）was used to detect the electrochemical signal.Under the optimal conditions,the results showed that the linear range of the electrochemical toxin sensor was 0.02 pg/m L-2 ng/m L,and the detection limit was 0.018pg/m L（3 times of signal-to-noise ratio）.The sensor had good accuracy,stability and selectivity,and successfully applied to the detection of AFB1in milk samples.The AFB1 sensor has great practical value.2.Ultrasensitive nonenzymatic glucose sensor of ZIF-67nanocomposites based on in situ synthesizing copper oxide nanoparticles on metal-organic framework.In this chapter,metal-organic framework materials（ZIF-67）with regular morphology was synthesized,and copper oxide nanoparticles/ZIF-67 composites（Cu ONPs/ZIF-67）was obtained by in-situ synthesis.The morphology and composition of Cu ONPs/ZIF-67were analyzed by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）and X-ray diffraction（XRD）.Cu ONPs/ZIF-67 solution was dripped onto the surface of GCE,and dried.The catalytic performance of the modified electrode for glucose oxidation in alkaline environment was studied,and a Cu ONPs/ZIF-67nonenzymatic glucose sensor was constructed.Under the optimal conditions,the linear range of the sensor was 0.1μM-1400μM,and the detection limit was 0.02μM.The proposed sensor had good accuracy,stability and selectivity,and was successfully applied to the detection of glucose in human serum.The electrochemical nonenzymatic glucose sensor based on Cu ONPs/ZIF-67 has a good prospect in the detection of glucose.