Alimagham Farah, Platkov Max, Prestage Joshua, Basov Svetlana, Izakson Gregory, Katzir Abraham, Elliott Stephen R, Hutter Tanya
Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
Nuclear Research Center Negev Beer-Sheva 84190 Israel.
RSC Adv. 2019 Jul 8;9(37):21186-21191. doi: 10.1039/c9ra04104d. eCollection 2019 Jul 5.
The increasing awareness of the harsh environmental and health risks associated with air pollution has placed volatile organic compounds (VOCs) sensor technologies in elevated demand. While the currently available VOC-monitoring technologies are either bulky and expensive, or only capable of measuring a total VOC concentration, the selective detection of VOCs in the gas-phase remains a challenge. To overcome this, a novel method and device based on mid-IR evanescent-wave fiber-optic spectroscopy, which enables enhanced detection of VOCs, is hereby proposed. This is achieved by increasing the number of analyte molecules in the proximity of the evanescent field capillary condensation inside nano-porous microparticles coated on the fiber surface. The nano-porous structure of the coating allows the VOC analytes to rapidly diffuse into the pores and become concentrated at the surface of the fiber, thereby allowing the utilization of highly sensitive evanescent-wave spectroscopy. To ascertain the effectiveness and performance of the sensor, different VOCs are measured, and the enhanced sensitivity is analyzed using a custom-built gas cell. According to the results presented here, our VOC sensor shows a significantly increased sensitivity compared to that of an uncoated fiber.
人们对空气污染所带来的严峻环境和健康风险的认识日益提高，这使得挥发性有机化合物（VOCs）传感器技术的需求不断增加。虽然目前可用的VOC监测技术要么体积庞大、价格昂贵，要么只能测量总VOC浓度，但气相中VOC的选择性检测仍然是一个挑战。为了克服这一问题，本文提出了一种基于中红外倏逝波光纤光谱的新型方法和装置，该方法能够增强对VOCs的检测。这是通过增加倏逝场附近的分析物分子数量来实现的，即通过光纤表面涂覆的纳米多孔微粒内部的毛细管冷凝作用。涂层的纳米多孔结构使VOC分析物能够迅速扩散到孔隙中并在光纤表面浓缩，从而能够利用高灵敏度的倏逝波光谱。为了确定传感器的有效性和性能，对不同的VOCs进行了测量，并使用定制的气室分析了增强的灵敏度。根据本文给出的结果，我们的VOC传感器与未涂覆光纤相比，灵敏度显著提高。
