A fluorescence sensing method for brilliant blue with gold nanoclusters based on the inner filter effect

One-step synthesis of blue emission copper nanoclusters for the detection of furaltadone and temperature

Polyvinyl pyrrolidone (PVP), playing roles as a templating agent, can be applied to prepare blue-emitting copper nanoclusters (Cu NCs@PVP) on the basis of a rapid chemical reduction synthesis method. The Cu NCs@PVP displayed a blue emission wavelength at 430 nm and the corresponding quantum yield (QY) could reach 10.4%. Subsequently, the as-synthesized Cu NCs@PVP were used for the trace analysis of furaltadone based on the inner filter effect (IFE) between Cu NCs@PVP and furaltadone, which caused the fluorescence to be effectively quenched. Additionally, this proposed determination platform based on the Cu NCs@PVP for furaltadone sensing possessed an excellent linear range from 0.5 to 100 μM with a lower detection limit of 0.045 μM (S/N = 3). Meanwhile, the Cu NCs@PVP also could be applied for the sensing of temperature. Furthermore, the practicability of the sensing platform has been successfully verified by measuring furaltadone in real samples, affirming its potential to increase fields for the determination of furaltadone.

Rapid optical sensor for recognition of explosive 2,4,6-TNP traces in water through fluorescent ZnSe quantum dots

In this report, blue fluorescent zinc selenide quantum dots (ZnSe QDs) were synthesized using 3-mercaptopropionic acid through a direct aqueous route at a lower temperature of 70 °C. The photoluminescence (PL) characteristics of ZnSe QDs have been employed to recognize nitroaromatic compounds, i.e., traces of 2,4,6-TNP (picric acid) in water. The sensing of nitroaromatic compounds was performed via fluorescence techniques. The PL band of ZnSe QDs observed at 490 nm is selectively quenched with an increasing concentration of picric acid in DI water and river water. For the proposed sensing probe, the Stern-Volmer (S-V) plot shows linearity over the range of 2.0 µM-0.25 mM with the detection limit of 12.4 × 10^-6 M without any interference effect of other nitroaromatic compounds. The plausible mechanism of PL quenching is considered as the inner filter effect, based on absorption, PL and PL lifetimes.

A new method for cartap detection with high sensitivity and selectivity based on the inner filter effect between GSH-Cu NCs and Au NPs

Herein, a novel and sensitive fluorescence method for cartap determination is established on the basis of the inner filter effect (IFE) of gold nanoparticles (Au NPs) on the fluorescence of glutathione protected Cu NCs (GSH-Cu NCs). In the presence of Au NPs, the fluorescence of GSH-Cu NCs was strongly quenched by the IFE because the absorption spectra of Au NPs overlap well with the emission spectra of GSH-Cu NCs. Upon addition of cartap, cartap could induce the aggregation of Au NPs whose absorption spectrum does not overlap with the emission spectrum of GSH-Cu NCs. Then, with the increase in cartap concentration, the IFE-decreased fluorescence was gradually recovered, realizing the fluorescence sensing of cartap. Under optimal conditions, the proposed method has a good linear relationship with cartap concentration in the range of 7-100 nM, and the detection limit is 3.34 nM. In addition, satisfactory results were obtained for cartap analysis using tap water and cabbage as real samples, which demonstrated that the method as-developed would have great practical application prospects.