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Optical fiber sensor for Hg(II) based on carbon dots
Helena M R Gonçalves1, Abel J Duarte, Joaquim C G Esteves da Silva
1Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua Campo Alegre 687, 4169-007 Porto, Portugal.
Biosensors & Bioelectronics
|August 3, 2010
Summary
A novel optical fiber sensor utilizes carbon dots to detect mercury (II) ions in water. This fast, reversible, and stable sensor enables sensitive detection of mercury in aqueous solutions.
Area of Science:
- Materials Science
- Analytical Chemistry
- Nanotechnology
Background:
- Mercury (II) ions (Hg(II)) pose significant environmental and health risks.
- Accurate and sensitive detection methods for Hg(II) in aqueous solutions are crucial.
- Optical fiber sensors offer advantages in remote and real-time monitoring.
Purpose of the Study:
- To develop a novel optical fiber sensor for the detection of Hg(II) in aqueous solutions.
- To immobilize carbon dots nanoparticles onto an optical fiber using a sol-gel method.
- To evaluate the sensing performance, including speed, reversibility, stability, and sensitivity.
Main Methods:
- Fabrication of a thin, homogeneous, and smooth sol-gel film on an optical fiber.
- Functionalization of carbon dots nanoparticles with PEG(200) and N-acetyl-L-cysteine.
- Immobilization of functionalized carbon dots within the sol-gel matrix.
- Utilizing fluorescence quenching for Hg(II) detection.
Main Results:
- A stable, homogeneous, and smooth sol-gel film (approx. 750 nm thick) was successfully prepared.
- The sensor demonstrated fast (less than 10 s) and reversible sensing capabilities.
- High stability was observed, with fluorescence intensity oscillations less than 1% after multiple calibration cycles.
- The sensor achieved detection of sub-micromolar concentrations of Hg(II) with a Stern-Volmer constant of 5.3×10^5 M⁻¹ at pH 6.8.
Conclusions:
- The developed optical fiber sensor provides a sensitive and reliable platform for Hg(II) detection.
- The sol-gel immobilization technique ensures sensor stability and reusability.
- This sensor technology holds promise for environmental monitoring and water quality assessment.
