Preparation And Application Of Of Derivtives Of Chitosan And Carbon Nanotubers Modified Electrode

The preparation methods, types and application of CNTs modified electrodes were described in this article in detail, especially in the fields of detection of metal ions using Chitosan. Hydroxypropyl Chitosan, O-hydroxypropyl-N-octyl chitosan and carbon nanotubers as the modifications. At the electrode surface, we constructed new interfaces. Also the article studied the applications and electrochemical behaviors of the modified electrodes. The main work was as follows:1. Chitosan/carbon nanotubers , hydroxypropyl chitosan/carbon nanotubers and O-hydroxypropyl-N-octyl chitosan/carbon nanotubers modified electrodes were prepared by dropping solutions directly on the electrode; cyclic voltammetry, AC impedance methods were employed to study the electrochemical properties of the sensors with the K3Fe(CN)6 as a chemical probe; sensitive redox peak of K3Fe (CN) 6 appeared on all the modified electrodes. To the chitosan/carbon nanotubers modified electrode, current of O-hydroxypropyl-N-octyl chitosan/carbon nanotubers modified electrodes increased a little and peak potential negatively shifted 50mV. Current of hydroxypropyl chitosan/carbon nanotubers modified electrodes significantly increased by 260% and peak potential negatively shifted 50mV.2. Electrochemical impedance spectroscopy(EIS) of bare electrode was almost a straight line indicating that the bare electrode process only controlled by diffusion; modified electrode showed semicircle in high frequency area, linear low-frequency area, the characteristics of this modified electrode showed that the electrode process was affected by the joint of dynamics and diffusion. Electron transfer resistance of O-hydroxypropyl-N-octyl chitosan/carbon nanotubers modified electrodes was largest and the hydroxypropyl chitosan/carbon nanotubers modified electrodes was smallest.3. Electrocatalytic properties of hydroxypropyl chitosan/carbon nanotubers modified electrodes for Zn²⁺ was investigated. When the scan rate was 100mV/s and the accumulation time was 100s, anodic peak of Zn²⁺ on the hydroxypropyl chitosan/carbon nanotubers modified electrodes was obtained at around -1.05V(vs.SCE) in NaAc-HAc solution which concentration was 0.1mol/L and pH was 5.8. In the range of l0～25μmol/L, a good linear relationship was obtained between concentration of Zn²⁺ and anodic peak current, and the detection limit was 1.0×10^-6mol/L(S/N=3). The modified electrode was simple in preparation and was of character of fast response and good reproducibility for Zn²⁺ determination.4. Electrocatalytic properties of hydroxypropyl chitosan/carbon nanotubers modified electrodes for Cu²⁺ was investigated. When the scan rate was 100mV/s and the accumulation time was 400s, anodic peak of Cu²⁺ on the hydroxypropyl chitosan/carbon nanotubers modified electrodes was obtained at around 0.01V(vs.SCE) in NaAc-HAc solution which concentration was 0.1mol/L and pH was 4.5. In the range of l～15μmol/L, a good linear relationship was obtained between concentration of Cu²⁺ and anodic peak current, and correlation coefficient of 0.996, the detection limit was 1.0×10^-7mol/L(S/N=3). The modified electrode was simple in preparation, and was of character of fast response and good reproducibility for Cu²⁺ determination.5. Electrocatalytic properties of hydroxypropyl chitosan/carbon nanotubers modified electrodes for pb²⁺ was investigated. When the scan rate was 100mV/s and the accumulation time was 150s, anodic peak of Pb2+ on the hydroxypropyl chitosan/carbon nanotubers modified electrodes was obtained at around 0.5V(vs.SCE) in NaAc-HAc solution which concentration was 0.1mol/L and pH was 4.8. In the range of l.8～10μmol/L, a good linear relationship was obtained between anodic peak current and concentration of pb²⁺, correlation coefficient of 0.99836. The detection limit of 1.5×10-7mol/L(S/N=3). The modified electrode was simple in preparation and was of character of fast response and good reproducibility for pb²⁺ determination. 6. The article analyzed energy of LUMO, HOMO and the optimized geometry structure of HPCHS in the method of quantum chemical calculation. And the reaction mechanism of detection of the metal ions by modified electrodes was infered. It was as follows:...