基于硫堇掺杂的聚乙烯醇薄膜的光波导传感器检测硫化氢气体

采用旋转甩涂法将硫堇掺杂的聚乙烯醇薄膜固定在K⁺交换玻璃光波导表面，研制出一种高灵敏硫化氢气体传感器。 传感膜与硫化氢(H₂S)气体作用时，薄膜颜色从紫色变为无色，从而降低薄膜对倏逝波的吸收，使传感器的输出光强度（信号）增强。 采用流动注射法对H₂S气体进行检测。 实验结果表明，H₂S传感器对浓度在0.14~56 mg/m3范围的H₂S气体具有良好的线性响应（r=0.99667）,检出限为0.11 mg/m³(S/N=3)，相对标准偏差为4.0%，响应时间（t90）＜2 s。 该传感器具有灵敏度高、响应快、可逆性和重复性好等特点。

Detection of H2 S Gas by Optical Waveguide Sensor Based on Thionine Doped Polyvinyl Alcohol Film

A highly sensitive hydrogen sulfide gas sensor was developed by immobilization of thionine dye doped polyvinyl alcohol film onto the surface of a K⁺ exchanged glass optical waveguide via a spin-coated method. The sensing film presents a color change from purple to colorless when exposed to H₂S gas, causing a decrease in the evanescent wave absorption of the film, and an increase of the output light intensity of the sensor(signal). The sensor performance was tested for the detection of H₂S gas by controlled flow injection. The experimental result shows that the sensor has a good linear response(r=0.99667) to H₂S gas in a range of 56 mg/m³ to 0.14 mg/m³. The detection limit for H₂S is 0.11 mg/m3(S/N=3). The RSD of output light intensity is 4.0% and response time(t90)＜2 s. This sensor shows high sensitivity, fast response, good reversibility and repeatability.