| Summary: | 碩士 === 國立臺灣師範大學 === 化學學系 === 86 ===
A C60/ Cryptand-22 coated piezoelectric quartz crystal membrane with a computer interface was prepared and applied as a piezoelectric urea sensor. The C60/cryptand-22 quartz crystal membrane showed adsorptive ability to adsorb ammonium ion which was the reaction product of the urease catalytic hydrolysis of urea.
The piezoelectric urea sensor exhibited quite good sensitivity and high selectivity for urea and various compounds, e.q., amines, alcohols, carboxylic acids, proteins, vitamines, glucose and metal ions showed almost no interference with the PZ urea sensor. Effects of pH value, solvent, urea concentration, urease injection, coated load and enzyme catalase, on the frequency response of the C60/Cryptand coated piezoelectric detector were also investigated. The piezoelectric urea sensor has exhibited good sensitivity of 2.35×103 Hz/M and good reproducibility for reusage. The detection limits with the piezoelectric urea sensor was about 4.75×10-5M for urea in solutions.
The mass increase of quartz crystal surface membranes caused the decrease in oscillating frequency of quartz. The variations of the crystal frequencies were converted to voltage with a frequency / voltage converter, and followed by amplification with OPA and data acquisition with analog to digital converter. (ADC).
The immobilized urease piezoelectric system was set-up based on a fullerene (C60)-urease /PVC. Urease was immobilized as C60-Urease. Effects of concentration of immobilizated urease, interference of other compounds and activity of immobilizated urease on the frequency response of the piezoelectric urea sensor were also investigated and discussed.
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