Facile synthesis of carbon nitride quantum dots as a highly selective and sensitive fluorescent sensor for the tetracycline detection

Abstract

The g-C3N4QDs were synthesized by a simple solvothermal “tailoring” process from bulk g-C3N4 which have a “strong quenching” behaviour in the presence of TC. The proposed fluorescent sensor has been successfully applied to detect TC in actual samples.

Meso-Au/BN Nanosensor for Trinitrotoluene Based on Fluorescence Resonance Energy Transfer and Surface-Enhanced Raman Spectroscopy Mechanisms

“…FRET occurs between the g-BN QDs on the meso-Au NP surface and TNT, resulting in the fluorescence quenching of g-BN QDs. The fluorescence evolution of the g-BN QDs to TNT was evaluated by the Stern–Volmer equation ( I 0 / I ) − 1 = k SV [ Q ] where I 0 and I are the fluorescence intensities of g-BN QDs in the absence and presence of the target analyte, respectively; k SV denotes the fluorescence quenching constant of the target analyte; and [ Q ] is the concentration of the target analyte. Figures S9 and S10 illustrate that the fluorescence intensities of the g-BN QDs and b-BN QDs evolved on the meso-Au NP surface in the absence and presence of TNT, DNT, TNP, and DNP, respectively, as the target species concentration increased from 0, 2 × 10 –6 , 4 × 10 –6 , 6 × 10 –6 , 8 × 10 –6 , 10 × 10 –6 , 1.2 × 10 –5 , and 1.4 × 10 –5 to 1.6 × 10 –5 mol·L –1 .…”

A dual-mode green emissive fluorescent probe for real-time detection of doxycycline in milk using a smartphone sensing platform

“…The fist absorption band at 253 nm is attributed to the π–π* transition of the sp 2 aromatic structures. 34 Other absorption bands at 326 and 400 nm may be due to surface chemical effects. Under 360 nm, NCNSs show an emission peak at 475 nm.…”

Graphitic Carbon Nitride Quantum Dots (g‐C3N4 QDs): From Chemistry to Applications

“…In general, g‐C 3 N 4 QDs have a broad optical absorption band that extends from the UV to the visible light region, with the typical absorption peak concentrated in the UV range. Compared to g‐C 3 N 4 in bulk, the absorption spectra of g‐C 3 N 4 QDs exhibit significant blue shifts [132,146] . This is probably because the size effect makes the conduction and valence bands move in opposite directions.…”

“…The fact that the diffraction peaks of g‐C 3 N 4 QDs and those of bulk g‐C 3 N 4 are quite similar and agree with one another strongly suggests that the two substances have the same fundamental crystal structure. Both the strong peak at 27.5°, which corresponds to the (002) plane, and the relatively weak peak at 13.1°, which is attributed to the (100) plane, can be seen in the diffraction pattern [132] . Both distinctive diffraction peaks reflect, respectively, the inter‐planar stacking of the aromatic ring structure and the in‐planar tri‐s‐triazine unit packing motif [83] .…”

“…A relative PLQY is calculated by comparing the absorbance and emission of a molecule to a molecular dye with a known PLQY and a similar PL emission window. There has been a wide range of relative PLQY values reported for g‐C 3 N 4 QDs, ranging from 14.5 to 96 % [58,78,104,129,132,138,159] …”