基于表面开孔光纤的集成式亚硝酸盐微流荧光传感器

利用中空悬挂芯光纤研制了一种将荧光猝灭反应区建立在空心光纤内部的光纤集成荧光在线微流传感器。利用CO2激光器在光纤表面刻蚀微孔,使得试剂可由微孔注入光纤内部并混合形成稳定的微流。在悬挂芯光纤纤芯倏逝场的激发下,指示剂分子产生荧光,所产生的荧光被耦合到纤芯内部并在出射端被检测。文中利用光纤内部的荧光猝灭反应实验确定了亚硝酸盐溶液的浓度。结果显示:微流可在短时间通过光纤,传感器能以较快的速度检测溶液浓度。另外,当亚硝酸盐溶液的浓度为0.1~2.6mmol/L时,荧光猝灭程度与溶液浓度呈较好的线性关系,结果证明了该集成式光纤内微流控传感器方案用于微量荧光检测的可行性。

Integrated microfluidic nitrite fluorescence optical fiber sensor based on optical fiber with microholes on surface

An in-fiber integrated fluorescence online optofluidic sensor was developed by using a hollow optical fiber with a suspended core, in which the micro-region of the sensor for fluorescence quenching reaction was built in the hollow optical fiber. Microholes on the surface of the fiber were etched by a CO₂ laser, the fluorescence reagents could be injected into the optical fiber via the microholes and was mixed to form stable microflows in the fiber. Concurrently, indicator molecules were excitated by the evanescent field of the suspended core, the fluorescence was well coupled into the core and was detected in the exited end. The concentration of nitrite was determined by fluorescence quenching reaction during optofluidic reaction in the optical fiber. Experimental results indicate that the microflows could flow through the optical fiber in a short time, therefore, the sensor detects the solution concentration in a fast response rate.Moreover, the fluorescence response of the sensor is nearly linear depending on the concentration of nitrate in the range of 0.1-2.6 mmol/L, which reveals the feasibility of the integrated in-fiber optofluidic method for trace fluorescence detection.