Sulfur-Doped Graphene Quantum Dots as a Novel Fluorescent Probe for Highly Selective and Sensitive Detection of Fe³⁺

Abstract

Sulfur-doped graphene quantum dots (S-GQDs) with stable blue-green fluorescence were synthesized by one-step electrolysis of graphite in sodium p-toluenesulfonate aqueous solution. Compared with GQDs, the S-GQDs drastically improved the electronic properties and surface chemical reactivities, which exhibited a sensitive response to Fe(3+). Therefore, the S-GQDs were used as an efficient fluorescent probe for highly selective detection of Fe(3+). Upon increasing of Fe(3+) concentration ranging from 0.01 to 0.70 μM, the fluorescence intensity of S-GQDs gradually decreased and reached a plateau at 0.90 μM. The difference in the fluorescence intensity of S-GQDs before and after adding Fe(3+) was proportional to the concentration of Fe(3+), and the calibration curve displayed linear regions over the range of 0-0.70 μM. The detection limit was 4.2 nM. Finally, this novel fluorescent probe was successfully applied to the direct analysis of Fe(3+) in human serum, which presents potential applications in clinical diagnosis and may open a new way to the design of effective fluorescence probes for other biologically related targets.

Enhancing the luminescence of carbon dots by doping nitrogen element and its application in the detection of Fe(III)

“…CDs have a potential as replacements for toxic metal-based quantum dots (QDs) and are proved to be promising candidates in many applications such as medical diagnosis [5], bio-images [4,[6][7][8][9][10], detection of metal ions [11][12][13][14][15] and catalysis [16,17]. Recently, a variety of methods, including laser ablation of graphite [18,19], electrochemical oxidation of graphite [20] and carbon nanotubes [21], thermal treatment of gelatin [22] or EDTA2Na [23], acid treatment of sucrose solution or glucose [24][25][26][27] and microwaving of Ionic liquids [28] or chitosan [29] etc., have been adopted in the preparation of C-dots.…”

Facile synthesis of N-rich carbon quantum dots from porphyrins as efficient probes for bioimaging and biosensing in living cells

“…[23][24][25][26][27][28][29] Lanthanide-doped CQDs can act as new probes with near infra-red fluorescence or fluorescence/magnetic resonance dual response. [30][31][32][33] However, the development of functional CQDs doped with transition metal using fixed metal complexes as precursors is yet to be reported.…”

The chemical redox modulated switch-on fluorescence of carbon dots for probing alkaline phosphatase and its application in an immunoassay

“…It is seen that the resultant CDs show two weak absorption peaks at 242 nm and 320 nm which are ascribed to the p-p* transition of C]C bonds and n-p* transition of C]O bonds in the CDs. 33,34 The emission spectrum shows that a strong emission with a maximum emission wavelength at 412 nm could be observed under excitation at 320 nm. Strong blue photoluminescence was seen under UV light (inset in Fig.…”