Study On Electrochemical Sensor Of Carbon Nanomaterials

Due to unique spatial structural, mechanical, electrical and electrochemical properties, carbon nanomaterials had received much attention by many researchers. According to different fabrication methods, various kinds of carbon nanomaterials were gained, which were suitable for applications in physics, chemistry and material science. This thesis was concentrated on the utilization of carbon nanomaterials to construct multi-walled carbon nanotubes (MWCNTs), graphene and carbon fiber-based composite film modified electrodes for electrochemical biosensing, and valuable research results were obtained. The main points of this thesis were summarized as follows:(1) A MWCNTs/CS composite film was fabricated by utilizing CS as bonding agent. Ultraviolet spectra (UV) was used to observe the dissolution of MWCNTs in TPs solution, and cyclic voltammetry (CV) was employed to study the electrochemical behaviors of TPs at bare GCE and MWCNTs/CS/GCE. The large current response of TPs at the MWCNTs/CS electrode showed the excellent electrocatalytical activity of MWCNTs/CS/GCE towards the oxidation of TPs, increasing with 35-fold compared to GCE. Subsequently,the factors for TPs determination at MWCNTs/CS/GCE were also investigated. Finally, MWCNTs/CS/GCE was successfully used for TPs determination in real samples.(2) A PB-based first-generation glucose biosensor was fabricated by using the PB/PANi/MWCNTs hybrid composites. The glucose biosensor had been successfully used in glucose in vivo determination in rat brain. The cyclic voltammetry (CV) data showed that PB/PANi/MWCNTs/GCE could be stable in neutral or slightly alkaline PBS solution, and keep the redox peak current values of PB steady after 50 cycles. The PB-based modified electrode still remained the electrocatalytical activity to PB. Through cross-linking glucose oxidase (GOx), the GOx/PB/PANi/MWCNTs/CFME was fabricated. The biosensor showed fast responses, excellent selectivity,with a linear range of 0.05~4.0 mM, correlation of 0.995 and a detection limit of 5.0μM (S/N=3). In animal experiments, the glucose biosensor had successfully monitored glucose in vivo determination in rat brain with insulin model, and the results had agreed with reported articles.(3) A novel graphene-based pH sensor was successfully fabricated by using graphene pH-sensing film. The open-circuit potential data showed that the large responses were gained at graphene/AuE in PBS with various pH values, with a linear range of pH 1.0~13.0 and a sensitivity of 42.43 mV/pH. Subsequently, through cross-linking acetylcholinesterase (AChE), the acetylcholine (ACh) biosensor was fabricated. The experiment results suggested that the good responses were gained at AChE/graphene/AuE in 0.9% NaCl solution (pH7.0, unbuffered) containing with various concentration of ACh, with a linear range of 20~260μM, a sensitivity of 42.85 mV /μM and a detection limit of 5.0μM (S/N=3).