Infrared tapered fiber ring sensor for environmental detection of organic pollutants.

Industrial manufacturing, agricultural production, and domestic waste have led to severe environmental pollution, significantly impacting human health and the environment. The analysis of complex organic pollutants in aquatic environments is an inevitable issue in environmental monitoring. This paper introduces a tapered fiber ring sensor based on mid-infrared fiber evanescent wave spectroscopy (MIR-FEWS), which is one of the emerging technologies for detecting the food and chemical industry, environmental monitoring, battery chemistry, and medical applications. The sensor was prepared by tapering and bending a Ge 10 As 30 Se 38 Te 22 (GAST) infrared fiber. The influence of parameters such as waist diameter (d w), bending radius (r b), and bending circles (c b) on the sensor performance was discussed with the COMSOL simulation results. The optimal performance sensor with parameters d w = 50 µm, r b = 0.5 mm, and c b = 4 has a sensitivity of 1.490 ± 0.024 a.u./vol% and a limit of detection (LoD) of 0.058 ± 0.001 vol% for ethanol (CH 3 CH 2 OH) solutions. The hydrophobicity of the GAST fiber improves the sensitivity for detecting benzaldehyde (C 6 H 5 CHO) in the benzyl alcohol (C 6 H 5 CH 2 OH) and C 6 H 5 CHO aqueous solution. Finally, we successfully identified three organic compounds, C 6 H 5 CH 2 OH, C 6 H 5 CHO, and acetonitrile (CH 3 CN) in the wastewater and determined their concentrations as 0.460 ± 0.015 vol%, 0.176 ± 0.007 vol%, and 1.091 ± 0.024 vol%, respectively. The optical fiber sensor has great application potential in the field of multi-component organic matter analysis. • Infrared fiber ring sensor with high sensitivity (1.490 a.u./vol%) and low LoD (0.058 vol%) for ethanol is invented. • Qualitative and quantitative analysis of VOCs in wastewater are realized by infrared fiber ring sensor. • Compared with ATR-FTIR technique, infrared fiber ring sensor has higher sensitivity and lower LoD. • The strong hydrophobicity of the fiber improves the sensitivity to detect aldehydes. [ABSTRACT FROM AUTHOR]