scholarly journals Carbon Quantum Dots Prepared with Chitosan for Synthesis of CQDs/AuNPs for Iodine Ions Detection

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1043 ◽  
Author(s):  
Juanjuan Song ◽  
Li Zhao ◽  
Yesheng Wang ◽  
Yun Xue ◽  
Yujia Deng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Color Change ◽  
Colorimetric Method ◽  
High Sensitivity ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots ◽  
Water Soluble ◽  
Synthetic Process ◽  
Iodide Ions

Water-soluble and reductive carbon quantum dots (CQDs) were fabricated by the hydrothermal carbonization of chitosan. Acting as a reducing agent and stabilizer, the as-prepared CQDs were further used to synthesize gold nanoparticles (AuNPs). This synthetic process was carried out in aqueous solution, which was absolutely “green”. Furthermore, the CQDs/AuNPs composite was used to detect iodine ions by the colorimetric method. A color change from pink to colorless was observed with the constant addition of I− ions, accompanied by a decrease in the absorbance of the CQDs/AuNPs composite. According to the absorbance change, a favorable linear relationship was obtained between ΔA and I− concentration in the range of 20–140 μM and 140–400 μM. The detection limit of iodide ions, depending on the 3δ/slope, was estimated to be 2.3 μM, indicating high sensitivity to the determination of iodide. More importantly, it also showed good selectivity toward I− over other anion ions, and was used for the analysis of salt samples. Moreover, TEM results indicated that I− ions induced the aggregation of CQDs/AuNPs, resulting in changes in color and absorbance.

β-Cyclodextrin functionalized carbon quantum dots as sensors for determination of water-soluble C60 fullerenes in water

The Analyst ◽  
2016 ◽  
Vol 141 (9) ◽  
pp. 2682-2687 ◽  
Author(s):  
Angelina Cayuela ◽  
M. Laura Soriano ◽  
Miguel Valcárcel
Keyword(s):  
Quantum Dots ◽  
Direct Determination ◽  
Carbon Quantum Dots ◽  
Water Soluble ◽  
Soluble C ◽  
Water Soluble C ◽  
C60 Fullerenes

A selective photoluminescence method based on Carbon Quantum Dots (CQDs) functionalized with carboxymethyl-β-cyclodextrin for the direct determination of water-soluble C60 fullerene has been developed.

Biological Activity Test of Dendrobium Huoshanense and Its Application in the Detection of Environmental Pollutant Phenols

2021 ◽  
Vol 13 (7) ◽  
pp. 1205-1214
Author(s):  
Yujuan Wang ◽  
Jun Dai ◽  
Peipei Wei ◽  
Yongping Cai ◽  
Bangxing Han
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Reaction ◽  
High Sensitivity ◽  
Carbon Quantum Dots ◽  
Environmental Pollutant ◽  
One Step ◽  
New Type ◽  
Filtration Effect ◽  
Dendrobium Huoshanense

ABSTRACTIn this research, a new type of carbon quantum dot was prepared from Dendrobium huoshanense via one-step hydrothermal reaction at 200 °C for 6 h. The as-derived carbon quantum dots exhibited good fluorescence properties, with quantum yield of 23.57%. The extraction and determination of Dendrobium huoshanense enzymes activity were performed for different incubation times to study the theoretical reference for the dynamic changes of the main enzyme activity in the process of Dendrobium huoshanense growth and the solid processing industry. The results demonstrated that Dendrobium huoshanense was a low toxic carbon source material. Moreover, the prepared carbon quantum dots exhibited high sensitivity for the detection of nonylphenol, allowing a range of linear response of 0.5–50 µM (R2 = 0.9997). The detection limit was a slow as 95.32 nM. These results indicated that fluorescence internal filtration effect influenced nonylphenol-induced quenching of the Dendrobium huoshanense-carbon quantum dots fluorescence. The Dendrobium huoshanense-carbon quantum dots were successfully used to track nonylphenol in environmental samples. Therefore, their exploitation offers a promising approach for environmental pollutant detection.

Quantitative Determination of Triglyceride by Photoactivated CdSe/ZnS Quantum Dots Through Fluorescence Assay

2008 ◽  
Vol 8 (7) ◽  
pp. 3434-3438 ◽  
Author(s):  
Chin-Ping Huang ◽  
Yaw-Kuen Li ◽  
Teng-Ming Chen
Keyword(s):  
Quantum Dots ◽  
Color Change ◽  
Low Cost ◽  
High Sensitivity ◽  
Assay System ◽  
Oil Refining ◽  
Quantitative Detection ◽  
Multiple Reactions ◽  
High Flexibility

The quantitative detection of triglycerides is an important issue for health inspection of metabolic disorders and for food and oil-refining industries. Many methods have been designed to approach this target, in which multiple reactions catalyzed by enzymes are normally coupled consecutively. In this study, we demonstrated a simple assay system containing lipase and photoactivated luminescent CdSe/ZnS quantum dots (QDs) for the quantitative detection of triglycerides. Photoactivated CdSe/ZnS QDs function as a sensitive "indicator" to reveal the minute acidity change of the assay system resulting from the enzymatic hydrolysis of triglycerides. By controlling the initial buffer condition of the assay system at 5, 10, or 20 mM phosphate buffer at pH 8.0, respectively, the quenching ratio of the QDs fluorescence intensity monitored at the maximum photoluminescence showed a linear correlation with the concentration of the examined triglyceride in the range of 0.02–6, 0.2–10, or 2–20 mM, respectively. The assay system also provides a convenient way to estimate triglyceride concentration by visualizing the color change of the QDs fluorescence. As compared to most of the existing methods, the system reported herein possessed many advantages, including simplicity, low cost, high flexibility, and high sensitivity. Furthermore, no complicated chemical modification or enzyme immobilization is needed.

The selective deprotonation of carbon quantum dots for fluorescent detection of phosphate and visualization of latent fingerprints

Nanoscale ◽  
2021 ◽  
Author(s):  
Li Yang ◽  
Qi Zhang ◽  
Ying Han ◽  
Hongjuan Li ◽  
Shiguo Sun ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Rapid Determination ◽  
Carbon Quantum Dots ◽  
Water Soluble ◽  
Fluorescent Detection ◽  
Latent Fingerprints ◽  
Fluorescent Sensing ◽  
Turn On ◽  
Sensing Platform

We developed a water-soluble, stable and selective “turn-on” fluorescent sensing platform based on carbon quantum dots (CQDs) for rapid determination of the phosphate (Pi) in aqueous solutions and visualization of...

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

scholarly journals Formation of Carbon Quantum Dots via Hydrothermal Carbonization: Investigate the Effect of Precursors

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 986
Author(s):  
Md Rifat Hasan ◽  
Nepu Saha ◽  
Thomas Quaid ◽  
M. Toufiq Reza
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Microcrystalline Cellulose ◽  
Uv Light ◽  
Synthesis Method ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots ◽  
Medical Diagnostics ◽  
Particle Size Range ◽  
Wide Range

Carbon quantum dots (CQDs) are nanomaterials with a particle size range of 2 to 10 nm. CQDs have a wide range of applications such as medical diagnostics, bio-imaging, biosensors, coatings, solar cells, and photocatalysis. Although the effect of various experimental parameters, such as the synthesis method, reaction time, etc., have been investigated, the effect of different feedstocks on CQDs has not been studied yet. In this study, CQDs were synthesized from hydroxymethylfurfural, furfural, and microcrystalline cellulose via hydrothermal carbonization at 220 °C for 30 min of residence time. The produced CQDs showed green luminescence behavior under the short-wavelength UV light. Furthermore, the optical properties of CQDs were investigated using ultraviolet-visible spectroscopy and emission spectrophotometer, while the morphology and chemical bonds of CQDs were investigated using transmission electron microscopy and Fourier-transform infrared spectroscopy, respectively. Results showed that all CQDs produced from various precursors have absorption and emission properties but these optical properties are highly dependent on the type of precursor. For instance, the mean particle sizes were 6.36 ± 0.54, 5.35 ± 0.56, and 3.94 ± 0.60 nm for the synthesized CQDs from microcrystalline cellulose, hydroxymethylfurfural, and furfural, respectively, which appeared to have similar trends in emission intensities. In addition, the synthesized CQDs experienced different functionality (e.g., C=O, O-H, C-O) resulting in different absorption behavior.

Rapid determination of melamine in milk using water-soluble CdTe quantum dots as fluorescence probes

2011 ◽  
pp. 1-12 ◽  
Author(s):  
Minwei Zhang† ◽  
Hong Ping† ◽  
Xianyi Cao ◽  
Hongkun Li ◽  
Fengrui Guan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Rapid Determination ◽  
Water Soluble ◽  
Cdte Quantum Dots ◽  
Fluorescence Probes
Sign in / Sign up

Export Citation Format

Share Document