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首页> 外文学位 >Fiber opticpH sensor for the acidic range using fluorescent dye-doped sol-gel materials.
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Fiber opticpH sensor for the acidic range using fluorescent dye-doped sol-gel materials.

机译：光纤pH传感器，用于酸性范围，使用掺杂荧光染料的溶胶-凝胶材料。

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摘要

A plethora of new sensor technologies have emerged for chemical, biological, environmental and security applications. However, their adoption has been constrained by lack of integration of vastly different technical areas. Fiber optic chemical sensing is one such technology; a combination of spectroscopy, materials science and optical engineering. In this work, the example of an acidic pH sensor is used to individually develop these three areas and integrate them into a working device. Acidic pH is an important parameter in chemical processes, with no suitable optical alternatives.; The fluorescent pH indicator 5-(and 6)-carboxydichlorofluorescein (CDCF) was doped in a sol-gel matrix. CDCF has a pKa of 4.53, making it well suited for the acidic range. MTMS and TEOS gels were developed as films with good mechanical and chemical stability. The pH state of the immobilized dye affects the ratio of the absorption peaks. The fluorescence spectrum was red shifted in the organically modified gel. The fluorescence of hybrid spin-coated thin films resembled that of TEOS gels rather than that of hybrid bulk gels. The pH response was reversible and repeatable with a dynamic range of 5 pH units. Changes in ionic strength cause hysteresis in the sensor's response, which disappears when the film surface is saturated with electrolytes. The mechanical strength of the films in air and when immersed in solution was improved by using specific aging routines. Photo-bleaching was reduced by limiting excitation time to the duration of the measurement. Sonication, organic modification and aging in pH 2 buffer reduced leaching of the dye. Solid surface energy of the gels increased with organic modification. Hybrid gels were hydrophobic, resulting in slow response times. The diffusion constant of hydronium ions was found to depend on protonation state of the indicator and ionic strength of the solution. The diffusion constant in 0%MTMS and 10%MTMS films was of the order of 10-9 cm2/s, while in 50%MTMS and 100%MTMS gels, it was of the order of 10-11 cm2/s. Sol-gel films with moderate organic modification and an appropriate aging cycle produced the effective pH sensors.
机译：已经出现了许多用于化学，生物，环境和安全应用的新传感器技术。但是，由于缺乏对各个不同技术领域的集成的限制，它们的采用受到了限制。光纤化学传感就是这样一种技术。结合了光谱学，材料科学和光学工程。在这项工作中，以酸性pH传感器为例分别开发了这三个区域并将它们集成到工作设备中。酸性pH是化学过程中的重要参数，没有合适的光学替代方法。将荧光pH指示剂5-（和6）-羧基二氯荧光素（CDCF）掺杂在溶胶-凝胶基质中。 CDCF的pKa为4.53，非常适合酸性范围。 MTMS和TEOS凝胶被开发为具有良好机械和化学稳定性的薄膜。固定染料的pH状态会影响吸收峰的比率。在有机改性的凝胶中，荧光光谱发生红移。混合旋涂薄膜的荧光类似于TEOS凝胶的荧光，而不是混合体凝胶的荧光。 pH响应是可逆的，并且在5个pH单位的动态范围内可重复。离子强度的变化会导致传感器响应出现滞后现象，当膜表面被电解质饱和时，该现象会消失。通过使用特定的老化程序，可以改善薄膜在空气中以及浸入溶液中时的机械强度。通过将激发时间限制在测量持续时间内，可以减少光致漂白。超声处理，有机改性和在pH 2缓冲液中的老化减少了染料的浸出。凝胶的固体表面能随着有机改性而增加。杂合凝胶是疏水的，导致响应时间慢。发现水合氢离子的扩散常数取决于指示剂的质子化状态和溶液的离子强度。在0％MTMS和10％MTMS膜中的扩散常数约为10-9 cm2 / s，而在50％MTMS和100％MTMS凝胶中，其扩散常数约为10-11 cm2 / s。具有适度有机修饰和适当的老化周期的溶胶-凝胶薄膜可生产出有效的pH传感器。

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  • 作者

    Manyam, Upendra H.;

  • 作者单位

    Rutgers The State University of New Jersey - New Brunswick.;

  • 授予单位 Rutgers The State University of New Jersey - New Brunswick.;
  • 学科 Chemistry Analytical.; Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 174 p.
  • 总页数 174
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;工程材料学;
  • 关键词

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