A small portion of an optical fibre clad was removed and coated with methylamine hydroiodide by a slurry deposition process to develop an evanescent wave optical fibre ammonia sensor. The experiment was performed for a few volatile organic compounds in order to understand the selectivity and sensitivity. Prior to the gas sensing measurement, the methylamine hydroiodide sample was characterised using X-ray diffraction (XRD), scanning electron microscope with energy dispersive X-ray spectroscopy, Fourier transform infrared, Raman, diffuse reflectance and UV–Vis spectroscopy. In order to understand the sensor response, the samples were independently exposed to acetone, ammonia, ethanol and methanol gases and then analysed using the XRD technique. This analysis reveals that the structural variation is observed because of the ammonia exposure as compared to other gases. It has initiated to fabricate a clad-modified optical fibre ammonia sensor that exhibits ∼28% of the sensitivity. These experimental results are discussed in detail.

中文翻译：

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具有碘化氢碘化物的van逝波光纤氨传感器

除去一小部分包层的光纤并通过浆液沉积工艺用碘化氢碘涂覆，以开发van逝波光纤氨传感器。为了了解选择性和灵敏度，对几种挥发性有机化合物进行了实验。在进行气敏测量之前，先使用X射线衍射（XRD），带有能量色散X射线光谱的扫描电子显微镜，傅立叶变换红外光谱，拉曼光谱，漫反射光谱和UV-Vis光谱对甲胺氢碘酸盐样品进行表征。为了了解传感器的响应，将样品分别暴露于丙酮，氨水，乙醇和甲醇气体，然后使用XRD技术进行分析。该分析表明，与其他气体相比，由于氨暴露而观察到结构变化。它已开始制造具有约28％灵敏度的包覆改性光纤氨传感器。这些实验结果进行了详细讨论。