Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany.
Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University of Jena, Fraunhoferstr. 6, 07743 Jena, Germany.
Sensors (Basel). 2018 Feb 6;18(2):478. doi: 10.3390/s18020478.
Due to a worldwide increased use of pharmaceuticals and, in particular, antibiotics, a growing number of these substance residues now contaminate natural water resources and drinking supplies. This triggers a considerable demand for low-cost, high-sensitivity methods for monitoring water quality. Since many biological substances exhibit strong and characteristic absorption features at wavelengths shorter than 300 nm, UV spectroscopy presents a suitable approach for the quantitative identification of such water-contaminating species. However, current UV spectroscopic devices often show limited light-matter interaction lengths, demand sophisticated and bulky experimental infrastructure which is not compatible with microfluidics, and leave large fractions of the sample analyte unused. Here, we introduce the concept of UV spectroscopy in liquid-filled anti-resonant hollow core fibers, with large core diameters and lengths of approximately 1 m, as a means to overcome such limitations. This extended light-matter interaction length principally improves the concentration detection limit by two orders of magnitude while using almost the entire sample volume-that is three orders of magnitude smaller compared to cuvette based approaches. By integrating the fibers into an optofluidic chip environment and operating within the lowest experimentally feasible transmission band, concentrations of the application-relevant pharmaceutical substances, sulfamethoxazole (SMX) and sodium salicylate (SS), were detectable down to 0.1 µM (26 ppb) and 0.4 µM (64 ppb), respectively, with the potential to reach significantly lower detection limits for further device integration.
由于全球范围内对药品的使用增加，特别是抗生素的使用，越来越多的这些物质残留现在污染了自然水资源和饮用水供应。这引发了对低成本、高灵敏度水质监测方法的巨大需求。由于许多生物物质在波长小于 300nm 处表现出强烈且特征性的吸收特征，因此紫外光谱法是定量识别此类水污染物质的一种合适方法。然而，目前的紫外光谱设备通常显示出有限的光物质相互作用长度，需要复杂而庞大的实验基础设施，与微流控不兼容，并使样品分析物的大部分未被利用。在这里，我们介绍了在充满液体的反共振空心光纤中进行紫外光谱的概念，该光纤具有约 1 米的大芯径和长度，可用于克服这些限制。这种扩展的光物质相互作用长度主要将浓度检测极限提高了两个数量级，同时几乎使用了整个样品体积——与基于比色皿的方法相比，小了三个数量级。通过将光纤集成到光流控芯片环境中，并在最低的实验可行传输带宽内运行，可检测到应用相关药物物质磺胺甲恶唑（SMX）和水杨酸钠（SS）的浓度低至 0.1µM（26ppb）和 0.4µM（64ppb），进一步的设备集成还有望达到更低的检测极限。
