Studies On The Application Of Founctional Carbon Nanotubes Modified Electrodes In Electrochemical Sensors And Biosensors

In this dissertation, efforts have been devoted to the fabrication, representation of 1, 10-phenanthroline-5, 6-dione functionalized carbon nanotubes (CNT)composite film modified electrodes and its application on electrochemical sensor and biosensor. The nanocomposites was fabricated by non-covalent bonding founction and represented by XPS and FIR. The dissertation consists of two main parts: one is the study of the 1, 10-phenanthroline-5, 6-dione functionalized carbon nanotubes (CNT) nanocomposite film electrode, and its application in ascorbic acid sensor. And the other is the electrochemical electrocatalytic oxidation of NADH with 1, 10-phenanthroline-5,6-dione functionalized carbon nanotubes (PD/CNT) nanocomposite film electrode and the amperometric alcohol biosensors based on integration of alcohol dehydrogenase onto the PD/CNT /GC electrodes.(1) The PD molecules were assembled on the surface of multiwall carbon nanotubes through spontaneous adsorption modified glassy carbon electrode (PD/CNT/GCE). We studied the pH-dependent response and the electron transfer kinetics of PD loaded on CNT (PD/CNT/GCE) in comparison with that of PD on conventional glass carbon (PD/GC). We also compared electrocatalytic activity toward AA oxidation of CNT, PD/GCE, and PD/CNT/GCE. The results showed that the PD/CNT/GCE nanocomposite exhibits a remarkably improved catalytic activity towards AA. When chose -0.1V as the work potential, the sensor exhibited a wide linear response up to 3 mM with a low detection limit of 0.8μM (S/N=3). The selectivity and stability of the biosensor were also investigated.(2) In the second part, we studied the catalytic activity of PD/CNT/GCE towards NADH. The kinetics of the catalytic reaction and the catalytic reaction rate constant (kh) was characterized using cyclic voltammetry techniques. For PD/CNT/GCE, a value of 7.26×103 M-1 s?1 was obtained. This value is a good explanation of the high catalytic activity. Alcohol dehydrogenase (ADH) was then immobilized on the PD/CNT/GCE by cross-linking with glutaraldehyde for the construction of the ethanol biosensor. Under the operation potential of 0.0V (vs. SCE) as prepared biosensor was highly selective for ethanol without the interference from DA, UA and AP and exhibited a wide linear range up to 7 mM with a lower detection limit of 30.4μM as well as a high sensitivity of 10.85 nA/mM.