Potyrailo R A, Hobbs S E, Hieftje G M
Department of Chemistry, Indiana University, Bloomington 47405, USA.
Anal Chem. 1998 Apr 15;70(8):1639-45. doi: 10.1021/ac970942v.
Fiber-optic near-ultraviolet evanescent-wave sensors have been constructed, and their feasibility for practical applications has been demonstrated. The sensors, used for the detection of ozone near the 254-nm peak of the Hartley absorption band, were fabricated from coiled segments of low-cost multimode plastic-clad silica optical fibers. The sensing sections were produced alternatively by stripping only the protective jacket from the fiber to expose the gas-permeable silicone cladding or by stripping the jacket and the cladding to expose the bare-silica fiber core. Response characteristics are given, including sensitivity to ozone, reversibility, and aging effects. The useful lifetime was unacceptably short for the sensor that employed the bare-silica core, whereas the exposed-cladding sensor demonstrated good stability over the entire two-month period of investigation. The latter, more useful sensor demonstrated a linear response to ozone over the range 0.02-0.35 vol% and a reversible response with a time constant on the order of 1 min. Differences in ozone absorption spectra obtained in the transmission and evanescent-wave modes are discussed. Projected applications of the new exposed-cladding sensor include ozone determination in water-treatment processes and ozone production plants.
已构建了光纤近紫外倏逝波传感器，并证明了其在实际应用中的可行性。这些用于检测哈特利吸收带254纳米峰值附近臭氧的传感器，由低成本多模塑料包层石英光纤的盘绕段制成。传感部分是通过仅剥去光纤的保护套以露出透气的硅酮包层，或者剥去护套和包层以露出裸石英光纤芯来交替制作的。给出了响应特性，包括对臭氧的灵敏度、可逆性和老化效应。对于采用裸石英芯的传感器，其使用寿命短得令人无法接受，而暴露包层的传感器在整个两个月的研究期间表现出良好的稳定性。后一种更实用的传感器在0.02 - 0.35体积%的范围内对臭氧呈现线性响应，且具有约1分钟时间常数的可逆响应。讨论了在透射和倏逝波模式下获得的臭氧吸收光谱的差异。新型暴露包层传感器的预期应用包括水处理过程和臭氧生产工厂中的臭氧测定。
