准确检测偏二氯乙烯的红外光纤倏逝波传感器

Infrared Optical Fiber Evanescent Wave Sensor for Accurate Detection of Vinylidene Chloride

利用中红外光纤构建了一种在线准确检测偏二氯乙烯的红外光纤倏逝波传感器,该传感器由U形中红外光纤传感探头、偏二氯乙烯选择性敏感膜和超疏水膜构成。四氟乙烯敏感膜涂覆在U形区表面,超疏水膜涂覆在偏二氯乙烯敏感膜表面。U形传感器可增强光纤表面倏逝波强度,从而提高传感器的灵敏度。敏感膜可实现对水体中偏二氯乙烯的选择性测量,提高传感器测量结果的准确性;超疏水膜可抑制水分子对测量结果产生的负面影响。实验研究了偏二氯乙烯的特征吸收光谱,以及传感器对偏二氯乙烯的响应灵敏度、响应时间和选择敏感性。从理论上建立了传感器测量偏二氯乙烯的理论模型。研究结果表明,传感器对偏二氯乙烯具有高选择敏感性,传感器灵敏度可达0.0021 abs/(mg·L^(-1)),响应时间为230 s。

An infrared optical fiber evanescent wave sensor for on-line and accurate detection of vinylidene chloride in water is fabricated in this work.The sensor is composed of a U-shaped mid-infrared optical fiber sensing probe,a vinylidene chloride selective sensitive membrane and a superhydrophobic membrane.The tetrafluoroethylene sensitive membrane was coated on the surface of the U-shaped area,and the superhydrophobic membrane was coated on the surface of the vinylidene chloride sensitive membrane.The U-shaped sensing region can enhance the intensity of the evanescent wave on the surface of the optical fiber,thereby improving the sensitivity of the sensor.The sensitive membrane can selectively detect the vinylidene chloride in water and improve the accuracy of the measurement results of the sensor.The superhydrophobic membrane can eliminate the negative influence of the water molecules on the measurement results.The characteristic absorption spectrum of vinylidene chloride,the response sensitivity,response time and selectivity of the sensor to the vinylidene chloride are studied experimentally.A theoretical model for measuring the vinylidene chloride by sensor is established.The results show that the sensor has high selective sensitivity to vinylidene chloride,the sensitivity is up to 0.0021 abs/(mg·L^(-1))and the response time is 230 s.