| Summary: | 碩士 === 華梵大學 === 電子工程學系碩士班 === 105 === In this thesis, the effects of different reference electrodes used in the homocysteine biosensors were analyzed. Titania nanotube array films were fabricated from high purity titanium foils (99.99%) by anodization. The Ti anode-electrode was placed in an electrolyte that consisted of ammonium fluoride, ethylene glycol and high-purity deionized water (DI water), and a platinum was used as the cathode-electrode. The titania nanotubes were fabricated in various temperature, and potentiostatic mode at 30 V for 1 h. The prepared titanium dioxide nanotubes have a high aspect ratio structure, providing a good electrons transport path. Finally, the cyclic voltammetry and impedance analysis were used to measure and discuss the results.
Homocysteine biosensors, based on titania nanotubes as a two-electrode system, were studied herein. The working electrode used was an immobilization of a D-amino acid oxidase enzyme by glutaraldehyde on titania nanotubes, and the reference electrode was a titania nanotube. The structure showed a reversible reaction in an electrochemical analysis. Similar cyclic voltammetry indicated that the sensitivity was 53.4 nA/μM, the corresponding correlation coefficient of linearity R2 was 0.998 in a detecting range from 0 and 70 μM, and the limit of detection was about 1.5 μM. The sensitivity of the corresponding to the lowest point of the graphic impedance real parts was -125 Ω/μM and the corresponding correlation coefficient of linearity R2 was 0.988. The |Z| sensitivity to various concentrations was -122 Ω/μM and linearity R2 was 0.990.
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