Highly Sensitive and Selective Detection of Nanomolar Ferric Ions Using Dopamine Functionalized Graphene Quantum Dots

Abstract

The good stability, low cytotoxicity, and excellent photoluminescence property of graphene quantum dots (GQDs) make them an emerging class of promising materials in various application fields ranging from sensor to drug delivery. In the present work, the dopamine-functionalized GQDs (DA-GQDs) with stably bright blue fluorescence were successfully synthesized for low level Fe(3+) ions detection. The as-synthesized GQDs are uniform in size with narrow-distributed particle size of 4.5 ± 0.6 nm and high quantum yield of 10.2%. The amide linkage of GQDs with dopamine, confirmed by using XPS and FTIR spectra, results in the specific interaction between Fe(3+) and catechol moiety of dopamine at the interfaces for highly sensitive and selective detection of Fe(3+). A linear range of 20 nM to 2 μM with a detection limit of 7.6 nM is obtained for Fe(3+) detection by DA-GQDs. The selectivity of DA-GQDs sensing probe is significantly excellent in the presence of other interfering metal ions. In addition, the reaction mechanism for Fe(3+) detection based on the complexation and oxidation of dopamine has been proposed and validated. Results obtained in this study clearly demonstrate the superiority of surface functionalized GQDs to Fe(3+) detection, which can pave an avenue for the development of high performance and robust sensing probes for detection of metal ions and other organic metabolites in environmental and biomedical applications.

Dramatic red fluorescence enhancement and emission red shift of carbon dots following Zn/ZnO decoration

“…When the pH was below 5, more amide groups were protonated. As the protonated amide groups had a much lower electron‐donating efficiency, the fluorescence intensity of Zn‐CDs decreased . Furthermore, Zn‐CDs had excellent photo‐stability and long‐term storage stability.…”

Excitons in Carbonic Nanostructures

“…This effect explains the very efficient quenching ability of all types of carbon nanostructures and is explored in different chemical sensor applications. Thus, the detection limit for sensing mercury cation [274,275] as well as of many other metal ions [276,277] reached several nanomoles.…”

Sulfur-doped graphene quantum dot-based paper sensor for highly sensitive and selective detection of 4-nitrophenol in contaminated water and wastewater

“…Besides, the emitted uorescence intensity increases at short wavelength of 310-330 nm and then decreases upon increasing the wavelength from 340 to 440 nm, which is consistent with the previous reports. 15,23,24 These obtained optical properties clearly indicate that S-GQDs can produce highest uorescence intensity at 330 nm, which may exhibit the superior photoluminescence property to detect 4-NP.…”

“…[13][14][15][16][17][18][19] GQDs have recently been used as the sensing materials for the detection of a wide variety of analytes including metal ions, organics, and biomolecules. [20][21][22][23][24] Usually the sensitivity of carbon-based quantum dots including carbon dots (CD) and GQDs toward analyte detection is dependent on quantum yield, which is related to the layers of quantum dots and dopants. The layer of GQDs is, in general, <10 layers and has less inuence on the quantum yield in comparison with CD.…”