Layer-by-layer immobilization of carbon dots fluorescent nanomaterials on single optical fiber

Gonçalves, Helena M. R.; Duarte, Abel J.; Davis, Frank; Higson, Seamus P. J.; Silva, Joaquim C. G. Esteves da

http://hdl.handle.net/10400.22/2036

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Authors

Gonçalves, Helena M. R.

Duarte, Abel J.

Davis, Frank

Higson, Seamus P. J.

Silva, Joaquim C. G. Esteves da

Abstract(s)

We report within this paper the development of a fiber-optic based sensor for Hg(II) ions. Fluorescent carbon nanoparticles were synthesized by laser ablation and functionalized with PEG200 and N-acetyl-l-cysteine so they can be anionic in nature. This characteristic facilitated their deposition by the layer-by-layer assembly method into thin alternating films along with a cationic polyelectrolyte, poly(ethyleneimine). Such films could be immobilized onto the tip of a glass optical fiber, allowing the construction of an optical fluorescence sensor. When immobilized on the fiber-optic tip, the resultant sensor was capable of selectively detecting sub-micromolar concentrations of Hg(II) with an increased sensitivity compared to carbon dot solutions. The fluorescence of the carbon dots was quenched by up to 44% by Hg(II) ions and interference from other metal ions was minimal.