The Investigation Of Electrochemical Glucose And Hydrogen Peroxide Sensors Based On Novel Nanocomposite Materitals

Electrochemical biosensor is the combination of the biological sensing technology and electrochemical technology,it has been a major analytical tool and gains increasing attention because of its simplicity,sensitivity,and specificity.In recent years,with the rapid growth of nano-technology in electrochemical biosensor,owing to their biocompatibility,catalytic properties,strong adsorption capacity and high surface-to-volume ratio,these nanomaterials can greatly improve the performance of biosensor.It has caused a remarkable innovation in the design and construction of electrochemical biosensors.Biosensors are being developed for different applications,including environmental and bio-process control,quality control of food,agriculture,military,and medical applications.Many nanomaterials with different morphology were synthesized in this thesis.Thus,these nanomaterials were used to fabricate novel biosensors and electrochemically nonenzymatic sensors.The first chapter mainly introduces the development of nanomaterials,the preparation of the electrochemical biosensor including the novel biosensors and electrochemically nonenzymatic sensors,and the application of nanomaterials in the electrochemical biosensor.The second chapter constructs a new amperometric biosensor based on Nafion,thionine and latinum nanowires,which was developed for sensitive detection of glucose.Initially,positively charged thionine molecules were immobilized onto the surface of Nafion-modified glassy carbon electrode through the interaction between-SO3-and-NH3+,and glucose oxidase was then assembled on the modified electrode by using platinum nanowires as the cross-linkage.The preparation process was characterized by using cyclic voltammetry.Experimental results indicated that the as-prepared biosensor could exhibit good electrocatalytic response toward glucose in the dynamic range of 1.0 ×10-5?6.0 ×10-3 mol L-1 with a detection limit of 3.0 ×10-6 mol L-1 at S/N = 3.The third chapter develops a new non-enzymatic electrochemical biosensor based on a hybrid material consisting of copper sulphide(CuS)and molybdenum disulfide(MoS2),which was used for sensitive detection of glucose.Under optimal conditions,experimental results indicated that the as-prepared biosensor modified with the CuS-MoS2 could exhibit good electrocatalytic response toward glucose in the dynamic range of 1.0 × 10-6?1.0 × 10-3 mol L-1 with a detection limit of 3.0 × 10-7 mol L-1 at S/N = 3.This non-enzymatic sensing electrode overcomes the defect of building enzyme sensor,such as complicated operations,poor stabilities,vulnerable to outside.The fourth chapter reports a non-enzymatic electrochemical sensing strategy for ultrasensitive detection of hydrogen peroxide(H2O2)at nanomolar levels.A glassy carbon electrode(GCE)was modified with a hybrid material consisting of multiwalled carbon nanotubes(CNTs)and molybdenum disulfide(MoS2).GCEs modified with carbon nanotubes,or nanoscaled MoS2,or with the MoS2-CNTs hybrid were investigated with respect to sensing H2O2,and this revealed that the GCE modified with the MoS2-CNTS hybrid performed best and resulted in the dynamic range of 1.0 × 10-8?1.0 × 10-4 mol L-1 with a limit of detection as low as 5.0 × 10-9 mol L-1 at S/N = 3.Moreover,the reproducibility and stability of the biosensor were acceptable,promising the applicability of this sensor in practical analysis.