Microchimica Acta

, 185:461 | Cite as

Microwave-assisted synthesis of thymine-functionalized graphitic carbon nitride quantum dots as a fluorescent nanoprobe for mercury(II)

  • Ojodomo J. AchaduEmail author
  • Neerish Revaprasadu
Original Paper


A microwave-assisted hydrothermal method was employed to prepare thymine-modified graphitic carbon nitride quantum dots (T-gCNQDs) which are shown to be a novel fluorescent nanoprobe for Hg(II). They exhibit excellent optical properties (blue emission with a fluorescence quantum yield of 46%) and water solubility. The incorporation of thymine into the gCNQDs results in an enhancement in photoluminescence properties. It is found that fluorescence, best measured at excitation/emission wavelengths of 350/445 nm, is much more strongly quenched by Hg(II) compared to the thymine-free nanoprobe. The quenching is highly selective even in the presence other metal ions. This is ascribed to the formation of T-Hg(II)-T base complexes. Fluorescence drops linearly in the 1.0 to 500 nM Hg(II) concentration range, and the limit of detection is 0.15 nM. The method was applied to the determination of Hg(II) in spiked samples of tap and pond water. Recoveries were found to be >95%, thus demonstrating the practical applicability of the assay.

Graphical abstract

A microwave-assisted hydrothermal route was employed to prepare thymine-functionalized graphitic carbon nitride QDs (T-gCNQDs). A selective fluorescence quenching mechanism occurred between T-gCNQDs and Hg(II) due to thymine functionalization. T-gCNQDs was utilized to detect Hg(II) in real samples.


Thymine Thymine-modified graphitic carbon nitride quantum dots Fluorescence quenching Stern-Volmer plot Nanoprobe 



The authors acknowledge the National Research Foundation (NRF), South Africa through the South African Research Chair Initiative (SARChI). OJA thanks the National Research Foundation (NRF) for a postdoctoral fellowship and funding under SA Research Chair for Nanotechnology.

Compliance with ethical standards

The author(s) declare that they have no competing interests.

Supplementary material

604_2018_3004_MOESM1_ESM.docx (239 kb)
ESM 1 (DOCX 239 kb)


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Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of ChemistryUniversity of ZululandKwaDlangezwaSouth Africa

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