The Preparation And Detection Of Electrochemical Glucose Sensor Based On Graphene/Gold Nanoparticles

Electrochemical sensors as an important branch of sensors,for its quick response,high sensitivity,good selectivity,simple operation and inexpensive,it has become one of the hotspots of current research.Nano materials such as graphene and mental nanoparticles which have special properties has imported to accelerate the electrochemical sensor's development and application.And it has been used to detect small molecules such as,H₂O₂,glucose,bioamines,and so on.Among then glucose detection is most important and significant due to the global disease diabetes,as well as the production monitoring and environmental detection.In this thesis,we used monolayer graphene material and gold nanoparticles as materials,dedicated to the preparation a new electrochemical sensor which is has a good homogeneity,stability and sensitivity.We assembled three different policies for gold nanoparticles uniform distribution to the surface of graphene,and prepared three kinds basal equably neat electrochemical sensor,summarized as follows:1.Nonenzyme hydrogen peroxide electrochemical sensor based on the planar graphene and gold nanoparticle hybrid.By modifying the surface of gold nanoparticle,changing the surface properties of gold nanoparticles,then using liquid-liquid interface self-assembly method to transfer gold nanoparticles evenly to the graphene surface,reach to the AuNPs@DDT-G hybrid electrode which surface is uniform and neat.We study the hybrid electrode with the scanning electron microscope?SEM?,X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?and Raman spectra.Small molecules hydrogen peroxide was tested by the electrode,the current response is linearly correlated to H₂O₂ concentration within the range of 0.1?mol/L to 400?mol/L with a correlation coefficient of 0.9963.The detection limit was down to 0.02?mol/L?S/N=3?.Furthermore,the sensor exhibits some other excellent characteristics,such as high selectivity,short response time,and long-term stability.2.Glucose biosensor based on the planar graphene and gold nanoparticle hybrid electrode.Using the dropping and drying method to prepared AuNPs/G basic electrode,via the Au-S bond to make the base electrode surface contained carboxyl,again through acylation forming amide bond fixed glucose oxidase,then produced the glucose electrochemical biosensors.We study the hybrid electrode with electron microscope?SEM?,X-ray diffraction?XRD?and infrared?IR?.The biosensor by testing hydrogen peroxide content indirectly to get the concentration of glucose in solution.Experiments show that the electrode response to glucose 95%steady current average response time less than 10 s,finally obtained the graphene/AuNPs-TGA-GOx glucose electrochemical biosensor standard curve to glucose,the current response is linearly correlated to glucose concentration within the range of 0.05 mmol/L to 10.55 mmol/L with a correlation coefficient of 0.9955.The detection limit was down to 0.01mM.Furthermore,the biosensor exhibits some other excellent characteristics,such as high selectivity,short response time,and long-term stability.3.Nonenzyme glucose biosensor based on the planar graphene and gold nanoparticle hybrid electrode.Using pulse current method to structure uniform neat AuNPs/G electrode.Chloroauric acid Auric sodium sulfite as the plating solution,and get the uniform spherical gold nanoparticles and dendritic gold nanoparticles surface structure AuNPs/G hybrid electrode,respectively.Pulse current method is convenient and simple,which can be mass production to the AuNPs/G electrode,by adjusting the strength of the pulse current and pulse time could control the performance.The AuNPs/G electrode has the electrochemical catalysis to glucose,and could get the excellent electrochemical signals.Experiment shows that the dendritic gold nanoparticles AuNPs/G hybrid electrode has a wide linear range from 0.02 mmol/L to 33 mmol/L with detection limit of 0.01 mmol/L to glucose.And spherical gold nanoparticles AuNPs/G hybrid electrode has a larger specific surface area with a sensitivity of 4.97?A·cm^-2mM^-1 to glucose which is four times than dendritic gold nanoparticle hybrid electrode.