Department of Environmental Biology and Chemistry, Graduate School of Science and Engineering for Research, University of Toyama, Toyama 930-8555, Japan.
Department of Applied Chemistry, School of Science and Technology, Meiji University, Kanagawa 214-8571, Japan.
Sensors (Basel). 2020 May 14;20(10):2796. doi: 10.3390/s20102796.
Herein, we propose an evanescent-wave fiber optic sensing technique for the anionic dye uranine based on ion association extraction. The sensor was prepared by removing a section of the cladding from a multimode fiber and hydrophobization of the exposed core surface. Uranine was extracted in association along with hexadecyltrimethylammonium (CTA) ion onto the fiber surface and detected via absorption of the evanescent wave generated on the surface of the exposed fiber core. The effect of CTA concentration added for ion association was investigated, revealing that the absorbance of uranine increased with increasing CTA concentration. A change in the sensor response as a function of the added uranine concentration was clearly observed. The extraction data were analyzed using a distribution equilibrium model and a Freundlich isotherm. The uranine concentration in the evanescent field of the fiber optic was up to 54 times higher than that in the bulk solution, and the limit of detection (3σ) for uranine was found to be 1.3 nM.
本文提出了一种基于离子缔合萃取的基于阴离子染料尿嘧啶的消逝波光纤传感技术。该传感器通过从多模光纤中去除一部分包层并对暴露的芯表面进行疏水处理来制备。尿嘧啶与十六烷基三甲基铵（CTA）离子一起缔合并提取到纤维表面，并通过检测暴露纤维芯表面产生的消逝波的吸收来检测。研究了添加用于离子缔合的 CTA 浓度的影响，结果表明，随着 CTA 浓度的增加，尿嘧啶的吸光度增加。明显观察到传感器响应随添加的尿嘧啶浓度的变化。使用分配平衡模型和弗伦德利希等温线对萃取数据进行了分析。光纤消逝场中的尿嘧啶浓度比在体相溶液中的浓度高 54 倍，并且发现尿嘧啶的检测限（3σ）为 1.3 nM。
