One-Pot Green Synthesis of High Quantum Yield Oxygen-Doped, Nitrogen-Rich, Photoluminescent Polymer Carbon Nanoribbons as an Effective Fluorescent Sensing Platform for Sensitive and Selective Detection of Silver(I) and Mercury(II) Ions

Abstract

This work reports on a facile, economical, and green preparative strategy toward water-soluble, fluorescent oxygen-doped, nitrogen-rich, photoluminescent polymer carbon nanoribbons (ONPCRs) with a quantum yield of approximately 25.61% by the hydrothermal process using uric acid as a carbon-nitrogen source for the first time. The as-prepared fluorescent ONPCRs showed paddy leaf-like structure with 80-160 nm length and highly efficient fluorescent quenching ability in the presence of mercury(II) (Hg(2+)) or silver (Ag(+)) ions due to the formed nonfluorescent metal complexes via robust Hg(2+)-O or Ag(+)-N interaction with the O and N of fluorescent ONPCRs, which allowed the analysis of Hg(2+) and Ag(+) ions in a very simple method. By employing this sensor, excellent linear relationships existed between the quenching degree of the ONPCRs and the concentrations of Hg(2+) and Ag(+) ions in the range of 2.0 nM to 60 μM and 5.0 nM to 80 μM, respectively. By using ethylenediaminetetraacetate and ammonia as the masking agent of Hg(2+) and Ag(+) ions, respectively, Hg(2+) or Ag(+) ions were exclusively detected in coexistence with Ag(+) or Hg(2+) ions with high sensitivity, and the detection limits as low as 0.68 and 1.73 nM (3σ) were achieved, respectively, which also provided a reusable detection method for Hg(2+) and Ag(+) ions. Therefore, the easily synthesized fluorescent ONPCRs may have great potential applications in the detection of Hg(2+) and Ag(+) ions for biological assay and environmental protection.

O-Phenylenediamine-Cysteine Nanosphere Having Conjugated Structures: A Highly Selective Fluorescent Probe for Mercury Ion

“…However the reaction between -SH and Hg 2+ were happened, the absorption peak of the -SH was obviously decreased. The peaks at 1239 and 1370 cm −1 were associated with the C-N stretching in the benzenoid and quinoid imine units, aromatic C=N heterocycles stretching vibrations are at1309−1650 cm −1 [41,42]. All the above observations indicate the successful formation of O-Cys including -SH.…”

“…4a, red curve).The most probable explanation for the quenching of PL of O-Cys in the presence of Hg 2+ was based on the electron transfer mechanism. That is, Hg 2+ is an acid of borderline hardness (according to the hard and soft acids and bases principle) and had strong affinity for sulfur donor atoms than the nitrogen atom, as result of forming the stable metal complexes [42]. Morever, when adding a strong Hg 2+ chelator (such as EDTA), Hg 2+ were removed from the surface of O-Cys by forming metal chelates with EDTA, which resulted in the PL recovery of O-Cys (Fig.…”

One-step Synthesis of Highly Luminescent Nitrogen-doped Carbon Dots for Selective and Sensitive Detection of Mercury(II) Ions and Cellular Imaging

“…The three peaks at 284.6, 285.7 and 287.9 eV would respectively correspond to C-C/C=C, C-N and C=O bonds. 37,38 Two peaks shown in the N 1s spectrum (Fig. 3C) at the binding energy of 399.5 and 401.4 eV can be respectively attributed to C-N-C and N-H. 39 Furthermore, the proportion of C-N-C accounted for 91.37%.…”

Reversible Fluorescence Probe Based on N-Doped Carbon Dots for the Determination of Mercury Ion and Glutathione in Waters and Living Cells

“…The limit of detection (LOD) was estimated to be 23 nM (~5 ppb) at a signal-to-noise ratio of 3, which is lower than the maximum contamination level of Hg 2+ in drinking water permitted by the World Health Organization (WHO, 6 ppb). 33,34 The superior sensitivity is much better than those for previous reported probes (Tables S1 and S2, Supporting Information). All these observations indicated that the N-CDs fluorescent sensing probe exhibits very promising application toward Hg 2+ detection.…”