Unique Approach To Develop Carbon Dot-Based Nanohybrid Near-Infrared Ratiometric Fluorescent Sensor for the Detection of Mercury Ions

Abstract

The ratiometric fluorescence assay, which can eliminate the external effects, has attracted great attention. In this work, a carbon dot (CD)-based nanohybrid dual-emission system was simply prepared by a unique approach of solvothermal treating corn bract and used as a ratiometric fluorescent sensor for Hg detection. Under a single excitation, the obtained nanohybrid sensor had two emission bands around 470 and 678 nm, which may originate from the intrinsic structure of CDs and chlorophyll-derived porphyrins, respectively. In the presence of Hg, the fluorescence at 678 nm could be remarkably quenched, while the fluorescence intensity at 470 nm was only slightly altered. The fluorescence intensity ratio at 470 and 678 nm exhibited a good linear relationship in the Hg concentration range from 0 to 40 μM with a detection limit of about 9.0 nM. It also had a satisfying assay performance in serum and river water samples. The prepared CD-based nanohybrid sensor here may hold the further potential applications in biomedicine study, environmental protection, and food safety.

Graphene Carbon Dot Assisted Sustainable Synthesis of Gold Quantum Cluster for Bio‐Friendly White Light Emitting Material and Ratiometric Sensing of Mercury (Hg2+)

“…This observation was supported by previous literature ,. Moreover it has been reported that Hg 2+ can quench the fluorescence of carbon dot through the interaction with electron‐rich aromatic ring . Thus, the slight decrease in fluorescent intensity of GQD from AuQC@GQD in the presence of Hg 2+ can be due to the electron transfer from electron‐rich aromatic ring of GQD and Hg (II).…”

Preparation of Triple‐Responsive Porous Silica Carriers and Carbon Quantum Dots for Photodynamic‐/Chemotherapy and Multicolor Cell Imaging

“…Figure a and b give the TEM image and size distribution of the prepared CQDs sample. From TEM image, it can be seen that the CQDs sample has uniform particle size with diameter of 2.5 nm, and the lattice spacing is about 0.25 nm (HRTEM insert), similar to the graphite (100) crystal facet . The corresponding size distribution curve exhibits a single peak, indicating that the CQDs sample is well dispersed.…”

“…At excitation wavelength of 420 nm, the CQDs solution exhibits the strong fluorescence emission (curve 3) and two emission peaks located at 506 and 676 nm are visible. The former may be from the intrinsic structure of CQDs and the latter is similar to the characteristic emission peak of the porphyrin derivative …”

“…The binding energies of O 1s (Figure c) are found at 532.9, 531.7 and 532.4 eV, proving the existence of O−C, O=C and O−N bond. The above results confirm the existence of oxygen‐containing functional groups . Furthermore, the high resolution of N 1s spectrum (Figure d) reveals the presence of pyridine‐like N (399.6 eV) and pyrrole‐like N (400.2 eV) atoms …”

“…For CQDs, the absorption peaks at 3431, 1726, 1551, 1460, 1355 and 1107 cm −1 indicate that CQDs were rich in hydrophilic functional groups such as amino, hydroxyl and carboxyl group. Apart from this, the peaks at 1643, 2925 and 2864 cm −1 were caused by the stretching vibration of the corresponding polycyclic aromatic hydrocarbon C=C, C=N and methyl methylene . The above results are consistent with the results obtained by XPS.…”