Application Of Carbon Nanotubes Modified Glassy Carbon Electrode In Small Drug Molecules Testing

Recently , chemically modified electrodes(CMEs) have been given highly investigations in the fields of electrochemistry and electroanalytical chemistry through various methods such as bonding, covalence, polymerization, adsoprtion methods. Some specific electrocatalytic substances are modified onto the surface of the naked electrodes to fabricate the CMEs, which make the electrochemical reactions to the desired directions. The CMEs have so much advantages including high sensitivity,relative simplicity and low cost of equipment that they are dramatically applied to the analytical detections.Since the discovery by Ijima in 1991,carbon nanotubes(CNTs) have attracted much attention because they have fascinating and extraordinary structural, mechanical, electrical, and electrochemical porperties. CNTs are arrangmenets of carbon hexagons that are formed into tiny tubes, and both ends of each single tube are closed with caps formed by carbon rings. The extraordniary electronic property of CNTs enables them to facilitate the electron transfer when they act as elctrode materials. Moreover, the properties including good adsorption capability, great specific surface and many functional groups linked on CNTs have ended with special electrocatalytic effect to the electrochemical behavior of some species. Futhermore, compared to many other electrodes CNTs modified electrodes exhibit excellent electrochemical properties. And an increasing attention is focused on how to control the modification of CNTs on the electrodes to improve the performance of CNTs modified electrodes and their application in various fields.In this thesis, we studied many kinds of dispersive systems including multiwall carbon nanotubes(MWCNTs)-Congo red(CR) solution, Nafion-MWCNTs solution and so on. And we fabricated these kinds of CNTs modified electrodes which have been successfully used to determine small molecule drugs with high sensitivity. These modified electrodes were characterized by using various methods, which give us new insight on the structure of modified layers and the electride reactions. The main works were summarized as follows:(1) The CME of Nafion -multiwalled carbon nanotubes (Nafion-MWCNTs) coated glassy carbon electrode (Nafion-MWCNTs/GCE) has been prepared. The electrochemical behaviors of bergenin and its electroanalytical method have been studied. Nafion-MWCNTs/GCE exhibited a remarkable catalytic and enhanced effects on the current response of bergenin. The property of kinetics were also studied, the results indicated that one-electron and one-proton transfer were involved in the electrode reaction process. Diffusion coefficient (D) and rate constant (k) have also been studied. Some experimental conditions were optimized.(2) A noncovalent approach for the dissolution and exfoliation of multi-walled carbon nanotubes with carboxyl (MWCNTs-COOH) in water by a rigid, planar and conjugated diazo dye, Congo red was reported. A highly sensitive measurement for salidroside was also shown at this electrode. The property of kinetics were also studied, the results indicated that one-electron and one-proton transfer were involved in the electrode reaction process. Diffusion coefficient (D) and rate constant (k) have beenstudied. Some experimental conditions were optimized. (3) The chemically modified electrode of single-walled carbon nanotubes with carboxyl (SWCNTs-COOH) coated glassy carbon electrode (SWCNTs-COOH/GCE) has been prepared. The prepared films were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of troxerutin and its electroanalytical method have been studied by cyclic voltammetry (CV).(4) The chemically modified electrode of SWCNTs coated glassy carbon electrode (SWCNTs /GCE) has been prepared. The prepared films were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of artemether and its electroanalytical method have been studied by CV. SWCNTs /GCE exhibited a remarkable catalytic and enhanced effects on the current response of artemether. The property of kinetics were also studied, the results indicated that two-electron transfer were involved in the electrode reaction process,Diffusion coefficient(D) and rate constant(k) were also studied. The stability and recovery of the SWCNTs /GCE are good.