Facile Approaches for Fabrication of Chemical Sensing Probes
|關鍵字:||化學感測探針;金奈米;銪;四環黴素;Chemical Sensing Probes;Gold Nanoparticles;Europium;Tetracycline|
本論文的第二部份則是發展可偵測四環黴素的螢光感測探針。由於銪離子可與四環黴素螫合產生螢光，因此可利用此特性發展偵測四環黴素的螢光感測探針，我們以二氧化矽為探針基材將表面修飾上銪離子用以感測四環黴素，同時也加入微波加熱萃取法縮短分析時間，藉著螢光的強弱可當作四環黴素的定量分析方法。實驗結果證實銪離子－玻璃片探針確實可感測四環黴素，但缺點是所需樣品量太大。因此本論文也發展出銪離子－光纖探針，小尺寸的光纖只需要極小的樣品量 (9.25 μL)，且能在真實樣品如雞湯溶液及血清溶液中感測低至4.44 ppb含量的四環黴素。
Chemical sensing probes are employed to interact with target species. Chemical signals such as optical signals may be generated after the interaction. The optical signals can be monitored using suitable spectroscopic methods. Chemical sensing probes with high sensitivity and specificity have been widely employed to rapid detection of target molecules and ions. Fabrication of mini-sized chemical sensing probes is of great interest in the development of chemical sensors. In this thesis, two mini-sized chemical sensing probes were proposed. In the first part of the thesis, gold nanoparticles were used as the reporter probes to roughly determine the concentrations of cationic surfactants in aqueous solutions based on the color change of gold nanoparticles. It resulted from their high absorption capacity in the visible region of electromagnetic spectrum and their negatively charged property on the surfaces. This approach was also applied to determine the concentration of cationic surfactants in a hair conditioner sample. The sensing mechanism of gold nanoparticles for cationic surfactants was studied by investigating the morphology of the generated gold nanoparticles using the mixture of gold nanoparticles and cationic surfactants as the template. The experimental results combined with the working hypothesis in terms of electrostatic interactions were employed to illustrate the sensing mechanism of gold nanoparticles for cationic surfactants. In the second part of thesis, solid substrates immobilized with Eu(III) were used as the probes to trap tetracycline (TC) from aqueous samples based on the generated luminescence of the complexes of Eu(III)-TC resulting from intermolecular energy transfer from TC to Eu(III). To accelerate the sensing process, microwave-assisted trapping was used to shorten the analysis time. The results show that the Eu(III)-modified glass probes can be used to determine TC from sample solutions by examining the luminescence of Eu(III)-TC on the probes. Additionally, optical fibers immobilized with Eu(III) were also successfully demonstrated to be suitable for being used as the sensing probes for TC. Only a small volume (9.25 μL) of sample solution was required for the analysis of TC in urine and serum samples. The detection limit was as low as 4.44 ppb. The proposed mini-sized probes in the study involve the advantages including speed, low cost, low sample consumption, short analysis time, and ease of fabrication. The probes potentially are suited for high-throughput analysis.