Abstract

Two competitive fiber optic sensors for the rapid, sensitive, and highly selective detection of mercury in water are designed, fabricated, and evaluated. A wavelength-modulated sensor based on an etched single-mode–multimode–single-mode (E-SMS) optical fiber structure and an intensity-modulated sensor based on fiber optics with a slanted end were fabricated by readily reproducible methods. The sensors were activated with a nanostructured chitosan/maghemite (${\text{CS}}/{{\text{Fe}}_2}{{\text{O}}_3}$) composite thin film for the selective detection of mercury ions (${{\text{Hg}}^{2 +}}$) in water. The functionalized sensors were implemented to experimentally validate the potential of ${\text{CS}}/{{\text{Fe}}_2}{{\text{O}}_3}$ thin film for optical sensing of ${{\text{Hg}}^{2 +}}$ in drinking water. The sensor based on the E-SMS structure exhibited a wavelength-modulated response with a sensitivity of up to 290 pm/(µg/mL), and the sensor based on the slanted end structure showed an intensity-modulated response with a sensitivity of ${-}{0.07}\;\text{dBm/}({\unicode{x00B5}{\text{g/mL}}})$. Validation of the experimental assay method proves the ability to selectively detect chemical interactions as low as 1 ng/mL (one part per billion) of ${{\text{Hg}}^{2 +}}$ in water for both sensors. The high specificity of the two sensors was demonstrated by evaluating their responses to a number of potentially interfering metal ions in water. These sensors are cost-effective, simple to construct, and easy to implement, which makes them very promising for the on-site detection and monitoring of mercury in bodies of water.

© 2023 Optica Publishing Group

Detection of copper ions in an aqueous solution by a dual-peak long period fiber grating functionalized with a polypyrrole–chitosan composite

Yaowei Li, Ting Liu, Kaixin Ge, Wenbo Gan, Shixun Dai, Tiefeng Xu, and Peiqing Zhang
Opt. Express 31(4) 6590-6600 (2023)

Fiber optic surface-plasmon-resonance-based highly sensitive arsenic sensor prepared using α-Fe₂O₃/SnO₂ core-shell nanostructure with optimized probe parameters

Sonika Sharma and Banshi Dhar Gupta
Appl. Opt. 57(36) 10466-10473 (2018)

In-fiber Mach-Zehnder interferometer based on hollow optic fiber for metal ion detection

Ming-Fu Liu, Jia-Wei Wang, and Shug-June Hwang
Opt. Express 30(15) 26006-26017 (2022)

Photochemical reflective optical fiber sensor for selective detection of phenol in aqueous solutions

Zhengkun Wang, Nianbing Zhong, Ming Chen, Haixing Chang, Dengjie Zhong, Yongwu Wu, Huimin Liu, Xin Xin, Mingfu Zhao, Bing Tang, Tao Song, and Shenghui Shi
Appl. Opt. 58(8) 2091-2099 (2019)

Ratio fluorescence sensor based on CD/Cu-MOFs for detection of Hg²⁺

Jingzhou Hou, Ya Zhang, Fanglin Ming, Yiyihui Hong, Huan Liu, Qiang He, Changjun Hou, and Danqun Huo
Appl. Opt. 62(6) A127-A136 (2023)