Selective detection of copper ion in complex real samples based on nitrogen-doped carbon quantum dots

Abstract

Highly selective nitrogen-doped carbon quantum dots (ND-CQDs) for copper ion (Cu) determination were synthesized by a solvent-free pyrolysis of citric acid and histidine. The resultant ND-CQDs display a stable bright blue fluorescence with a satisfactory product yield of 56% and quantum yield of 16%. The ND-CQDs not only show good photostability under continuous UV irradiation, but are also dramatically stable against extreme ionic strengths. The solid powders of the ND-CQDs re-dispersed in water still maintain a strong blue fluorescence after storing at room temperature for 6 months. The ND-CQDs can be employed to selectively detect Cu in a wide linear range of 0.6-30 μM. The detection limit is as low as 0.19 μM. The ND-CQDs were applied for Cu detection in environmental water samples, fruit juice samples, and urine sample. Satisfactory recoveries of 96-102% with relative standard deviations below 3% were obtained. The research provided a promising prospect for selective detection of Cu in the complex matrix. Graphical abstract Schematic illustration of the preparation of the ND-CQDs and its detection mechanism to Cu.

Environmentally exploitable biocide/fluorescent metal marker carbon quantum dots

“…Compared to the previous studies in the literature, the reported uorescence of CQDs decorated with S-and/or N-was sensitive to Cu 2+ and Fe 3+ ions, 79,80 while in the current work, the prepared CQDs decorated with hydroxyl groups are sensitive to Zn 2+ and Hg 2+ . The difference in sensitivity of the uorescence for CQDs against metal ions was attributed to the decorative groups 81 and consequently due to the interaction of Zn 2+ and Hg + ions with hydroxyl groups as the surface decorative groups of the applied CQDs.…”

Carbon Quantum Dots Based on Carbohydrates as Nano Sensors for Food Quality and Safety

“…Although the above‐mentioned methods have high selectivity, they often require tedious operation and expensive instruments. [ 95 ] The detection mechanism of heavy metals is based on the fact that interaction of such metals with nano sensors lead to quenching or enhancing of the fluorescence spectra, up to an excitation of 340 nm. Such effect involves the different sensing mechanisms mentioned in the Introduction.…”

“…[ 95 ] synthesized CQDs using citric acid as a carbon source and performed a test to determine the presence of Cu 2+ in fruit juice. [ 95 ] The dectection mechanism identified was charge transfer with dynamic quenching that resulted in the interaction between Cu 2+ and the nitrogen groups on the CQDs surface. Some reviewed LOD for Cu 2+ using CQDs nano sensors were 5, 10, and 190 nM.…”

“…Additional information about the accuracy can be found in Supporting information S.2. [ 59,95,99 ] Hg +2 can accumulate in marine plants and animals due to the environment pollution where marine species live. [ 100 ] As a virulent heavy metal, Hg +2 can cause motor and cognitive disfunction, kidney impairment, and cardiovascular disease through accumulation in the human body even at the trace level.…”

Parameters affecting the synthesis of carbon dots for quantitation of copper ions

“…4 Table S2 † lists the linear ranges and the LODs of different nanomaterial based probes toward the quantitation of Cu 2+ ions, showing that a lower LOD is provided by the I-C dots than that by the rest. [53][54][55][56][57][58][59][60] In addition, organic solvent is not required when applying this simple assay. Having high selectivity and a low LOD, the I-C dot probe holds great potential for the quantication of Cu 2+ ions in real samples containing complex matrixes.…”