Detection of Hg²⁺ by a Dual-Fluorescence Ratio Probe Constructed with Rare-Earth-Element-Doped Cadmium Telluride Quantum Dots and Fluorescent Carbon Dots

Abstract

Quantum dots (QDs) and carbon quantum dots (CDs) are classes of zero-dimensional materials whose sizes can be ≤10 nm. They exhibit excellent optical properties and are widely used to prepare fluorescent probes for qualitative and quantitative detection of test objects. In this article, we used cerium chloride as the cerium source and used the in situ doped cerium (rare-earth element) to develop cadmium telluride (CdTe) quantum dots following the aqueous phase method. CdTe: Ce quantum dots were successfully synthesized. The solution of CdTe:Ce QDs was mixed with the CD solution prepared following the green microwave method to form a ratio fluorescence sensor that can be potentially used for the selective detection of mercury ions (Hg 2+ ). We used transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and other microscopy and spectral characterization techniques to validate that Ce had been successfully doped. The test results on the fluorescence performance revealed that Ce doping enhances the predoped fluorescence performance of the CdTe QDs. We have quantitatively detected Hg 2+ using a ratiometric fluorescence sensor to show that in the range of 10–60 nM, the fluorescence quenching efficiency increases linearly with the increase in Hg 2+ concentration. The linear correlation coefficient R 2 = 0.9978, and its detection limit was found to be 2.63 nM L –1 . It was observed that other interfering ions do not significantly affect the fluorescence intensity of the probe. According to the results of the blank addition experiment, the developed proportional fluorescence probe can be used for the detection of Hg 2+ in actual samples.

A paper-based ratiometric fluorescence sensor based on carbon dots modified with Eu3+ for the selective detection of tetracycline in seafood aquaculture water

“…3D. TC can cooperate with Eu 3+ and act as the "antenna" to transmit the absorbed energy to Eu 3+ , 6 which can be proved by UV absorption spectra. Compared with that without TC, the absorption peaks of CDs-Eu and TC display an obvious red shift, while the emission peaks corresponding to Eu 3+ are enhanced (Fig.…”

“…Based on these advantages, lanthanidebased nanomaterials have received increasing attention. 6,7 The combination of CDs with lanthanide metal complexes is expected to achieve double-emission ratiometric fluorescence with high sensitivity. There are currently two approaches to functionalize CDs, namely elemental doping and surface modification.…”

Frontiers in Biotechnology: Emerging Approaches And Strategies

“…Cadmium quantum dots can also be used in conjugation with any rare earth metals of choice (Chu, H 2021) and ii) Pesticides with -Cl groups tend to have a higher binding affinity with the quantum dot which in turn may lead to higher chance of degradation of the pesticide (Sahoo, D 2018). Two recent reports suggested that functionalization of PbS quantum dots with gelatin has successfully lead to the detection of notorious pesticides like bentazon at a range of 0.05-200 ng/mL (Marahel, F 2022).…”

Highly sensitive and selective detection of butachlor based on the resonance light scattering of doped carbon quantum dots

“…40 In recent years, many researchers have blended CdTe and CQDs solutions to prepare a dual fluorescence detection system. 41,42…”