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The defense date of the thesis is 2013-08-05
The current date is 2019-03-22
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URN etd-0802113-150523 Statistics This thesis had been viewed 1591 times. Download 2 times. Author Yen-po Huang Author's Email Address No Public. Department Chemical Engineering Year 2012 Semester 2 Degree Master Type of Document Master's Thesis Language zh-TW.Big5 Chinese Page Count 111 Title Development of pH Electro-Chemical Biosensor Keyword pH sensor Film Electrochemical Miniaturized sensors Iridium oxide Iridium oxide Miniaturized sensors Electrochemical Film pH sensor Abstract Since many biological and chemical reaction mechanisms was related with the change of pH value and detecting the pH value of urine and blood could diagnose the diseases in Clinical research, pH sensor has been wildly used in many chemical factory, laboratory and hospital. The most common measure tool is the glass electrode. But glass electrode which is frangible and difficult to miniaturization did not correspond to the trend of human body sensor and miniaturization in modern clinical research. Therefore, many kinds of pH electrode have been developed gradually.
In this study, we used iridium oxide as the working electrode. The early research shows that iridium oxide is a good pH sensor. It has some advantage like well linear relationship at pH 2 ~ pH 12, high sensitivity, fast reaction time and could be accurate measured with stirring. The most important thing is that it could be manufacture in many ways. Because sputtering iridium oxide electrode was expensive, we produced the iridium oxide pH sensor by electrodeposition. And this sensor was used to detect the human urine. The results show that the iridium oxide electrode was interfered by the organics in the urine. The organic matter caused the deviation of sense voltage and corroded the surface material of working electrode. Thus, we used the Nafion to modify the surface of electrode in this research. The results show that the modified iridium oxide electrode has higher sensitivity 83.6mV/pH and response time in 1~3 S. And it could be used to detect the urine for 1000s and isolate the interfering substances from outside.
Reference electrode played an important role in electrochemical history. It could apply on electrochemical sensing and provided stable potential in two-pole sensing. In order to minify the sensor, the reference electrode also need to be minified. The reference electrode in this research was silver chloride electrode which covered by a layer of gel containing chloride ion and coated by an insulating layer. From the result, the potential drift was 15mV with the commercial Ag/AgCl reference electrode in long reaction time. It proved that the gel containing chloride ion could keep neutral of reference electrode and the covered chloroprene rubber could insulate the interference from outside and prevent the outflow of chloride ion in electrode.
With the working and reference electrode investigated above, we produced a miniature sensor which could detect with smallest amount of test solution by drop-sensing. This miniaturized sensor will be expect to have a great potential.
Advisor Committee Tza-chuan Chou - advisor
Wen-Fu Lee - advisor
Jyh-shyong Chang - co-chair
Ming-chang Yang - co-chair
Files Date of Defense 2013-07-22 Date of Submission 2013-08-05