On-off-on fluorescent carbon dots from waste tea: Their properties, antioxidant and selective detection of CrO42−, Fe3+, ascorbic acid and L-cysteine in real samples

Chen, Kui; Qing, Weixia; Hu, Wei‐Xiao; Lu, Minghua; Wang, Yong; Xiu-hua, Liu

doi:10.1016/j.saa.2019.01.066

Cited by 129 publications

(47 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of hydrophilic groups, such as hydroxyl, carboxyl, and amino groups, is responsible for the excellent water solubility of the prepared CQDs. The results correspond to other researcher's data [6,8,43,44].…”

Section: Scheme 1 Carbon Quantum Dots With the Free Carboxylic Groupsupporting

confidence: 89%

“…The highest QY was obtained for the Dot-1 sample prepared using tartaric acid (3.9%), probably due to the carboxylic and hydroxyl groups in its structure and Dot-1 (3.4%) obtained using formic acid. The quantum yield of the CQDs prepared by Chen et al [43] using waste tea as a precursor was around 7.1%, which is much lower than newly developed surface-modified carbon dots. Tang et al [3] prepared CQDs with a QY of 22%, however, in ethanol, not water, thus, in an aquatic environment their performance may be unsatisfactory for biological applications.…”

Section: Spectroscopic Properties Studymentioning

confidence: 81%

“…Conjugated unsaturated bonds are responsible for the luminescence properties, thus, their presence is desirable. Generally, all of the FTIR spectra are typical for quantum dots [43,44]. The spectrum of Dot-1-R shows carbon quantum dots modified with Rhod-OH.…”

Section: Scheme 1 Carbon Quantum Dots With the Free Carboxylic Groupmentioning

confidence: 99%

“…The first one, around 200 nm, comes from the π → π* transitions of C=C groups which are caused by the sp2 hybridization of the C atoms [2], whereas the peaks at 293 nm (Dot-2), 298 nm (Dot-3), 301 nm (Dot-1), and 301 nm (Dot-4) corresponds to n → π* transitions of C=O groups [2,38,39,43]. The UV-VIS spectrum is typical for carbon quantum dots and two different surface states can be distinguished which agrees with the data obtained by other researchers [2,6,8,43]. The UV-VIS results correspond to the FTIR spectra ( Figure 3) which showed bands typical for unsaturated carbon-carbon bonds as well as free carboxylic groups.…”

Section: Morphology Studymentioning

confidence: 99%

“…Figure 7 shows PL spectra of the obtained samples and their luminescence dependence on the pH values. Fluorescence spectra of the raw carbon dots (a: Dot-1; d: Dot-2; g: Dot-3; j: Dot-4) are typical for these quantum nanomaterials [2,4,6,8,37,38,43,44]. There is an obvious emission dependence on the visible excitation wavelength, which is typical for quantum nanobojects below 10 nm in size due to the surface defects, conjugated π-domains, as well as crystalline structure disturbance [1][2][3].…”

Section: Spectroscopic Properties Studymentioning

confidence: 99%

See 4 more Smart Citations

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

et al. 2020

View full text Add to dashboard Cite

Carbon quantum dots (CQDs) are nanoobjects of a size below 10 nm. Due to their favorable features, such as tunable luminescence, unique optical properties, water solubility, and lack of cytotoxicity, they are willingly applied in biomedicine. They can be obtained via bottom-up and top-down methods. However, to increase their quantum yield they must undergo post-processing. The aim of the following research was to obtain a new type of CQDs modified with a rhodamine b derivative to enhance their fluorescence performance without biocompability deterioration. For their preparation glucose was used as a precursor and four different carbonizing agents which affected semi-and final products luminescence properties. The ready nanomaterials were investigated over their chemical structure by FTIR and NMR, whereas morphology was investigated by the TEM method. Their optical properties were determined by UV-VIS spectroscopy. Fluorescence behavior, photo-and pH-stability, as well as solvatochromism showed their applicability in various biomedical applications due to the controlled properties. The samples exhibited excellent antioxidant activity and lack of cytotoxicity on L929 mouse fibroblasts. The results showed that proposed strategy enables preparation of the superior nanomaterials with outstanding luminescence properties such as quantum yield up to 17% which can be successfully applied in cell labelling, bioimaging, and theranostics.Molecules 2020, 25, 736 2 of 18 can release cadmium ions leading to cell death. Importantly, it occurred that quantum dots may undergo certain modifications resulting in the change of their surface or chemical structure [27,28]. Finally, their preparation is expensive. Therefore, there was a need for a novel type of quantum dots which would be suitable for biomedical applications. In 2004, a new type of carbon-based materials was accidentally obtained during nanotube purification [29]. Until then, numerous types of carbon quantum dots (CQDs) have been obtained with various possible applications due to their very attractive properties, such as luminesce, good water solubility, high photostability, resistance to photobleaching or photoblinking, possibility, chemical inertness and, finally, lack of toxicity and biocompability [1][2][3]. Furthermore, CQDs' region of photoluminescence is very broad, starting in the ultraviolet and ending in the near-infrared. Although, until now, the luminescence behavior of carbon nanodots is still not fully clear, it is believed that crucial role plays two factors, namely, that the quantum size is below 10 nm and surface defects which may act as excitation energy traps. Interestingly, CQDs can successfully act as both electron donors and acceptors [2][3][4].CQDs can be prepared from various resources, such as peels (mango, orange, banana, pineapple, onion, seaweed etc.), meat, grains, nuts, or vegetable by-products, which makes them a low-cost material [30,31]. Currently, these nanomaterials are widely applied in drug delivery, gene delivery, biosensing, bioimag...

show abstract

Section: Scheme 1 Carbon Quantum Dots With the Free Carboxylic Groupsupporting

confidence: 89%

Section: Spectroscopic Properties Studymentioning

confidence: 81%

Section: Scheme 1 Carbon Quantum Dots With the Free Carboxylic Groupmentioning

confidence: 99%

Section: Morphology Studymentioning

confidence: 99%

Section: Spectroscopic Properties Studymentioning

confidence: 99%

See 3 more Smart Citations

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

et al. 2020

View full text Add to dashboard Cite

show abstract

Carbon Dots: A Review with Focus on Sustainability

Ren,

Opoku,

Tang

et al. 2024

Advanced Science

View full text Add to dashboard Cite

Carbon dots (CDs) are an emerging class of nanomaterials with attractive optical properties, which promise to enable a variety of applications. An important and timely question is whether CDs can become a functional and sustainable alternative to incumbent optical nanomaterials, notably inorganic quantum dots. Herein, the current CD literature is comprehensively reviewed as regards to their synthesis and function, with a focus on sustainability aspects. The study quantifies why it is attractive that CDs can be synthesized with biomass as the sole starting material and be free from toxic and precious metals and critical raw materials. It further describes and analyzes employed pretreatment, chemical‐conversion, purification, and processing procedures, and highlights current issues with the usage of solvents, the energy and material efficiency, and the safety and waste management. It is specially shown that many reported synthesis and processing methods are concerningly wasteful with the utilization of non‐sustainable solvents and energy. It is finally recommended that future studies should explicitly consider and discuss the environmental influence of the selected starting material, solvents, and generated byproducts, and that quantitative information on the required amounts of solvents, consumables, and energy should be provided to enable an evaluation of the presented methods in an upscaled sustainability context.

show abstract

Arginine‐derived carbon nanoparticles for determination of Cr(VI) in water samples

Yahyazadeh

Shemirani

2020

Luminescence

View full text Add to dashboard Cite

Hexavalent chromium, Cr(VI), is a toxic and carcinogenic ion that poses significant risks toward human health and the environment. Due to its extensive industrial use and high water solubility, Cr(VI) can easily contaminate drinking water sources. Therefore, it is essential to develop methods to detect Cr(VI) in water samples. Recently, carbon quantum dots – being biocompatible, easy to synthesize, and cost‐effective fluorophores – have been successfully applied for the determination of different heavy metal ions. In this study, arginine‐derived carbon nanoparticles were synthesized using a solvent‐free one‐pot thermal method. These carbon nanoparticles were characterized using transmission electron microscopy, dynamic light scattering analysis, infrared spectroscopy, ultraviolet–visible (UV–vis) light spectroscopy, fluorescence spectroscopy, and CHNO elemental analysis before being used to design a sensor for Cr(VI). The sensor's signal was optimized and the arginine‐derived carbon nanoparticle‐based Cr(VI) determination method was shown to have a limit of detection of 18 nM, a limit of quantification of 60 nM, and a linear response range of 0.06–100 μM. The sensor's selectivity toward Cr(VI) was studied and a potential interfering ion was identified and dealt with. Finally, the sensor was successfully applied for the determination of Cr(VI) in tap water and mineral water samples.

show abstract

On-off-on fluorescent carbon dots from waste tea: Their properties, antioxidant and selective detection of CrO42−, Fe3+, ascorbic acid and L-cysteine in real samples

Cited by 129 publications

References 27 publications

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

Smart, Tunable CQDs with Antioxidant Properties for Biomedical Applications—Ecofriendly Synthesis and Characterization

Carbon Dots: A Review with Focus on Sustainability

Arginine‐derived carbon nanoparticles for determination of Cr(VI) in water samples

Contact Info

Product

Resources

About