scholarly journals Recycling Oxacillin Residues from Environmental Waste into Graphene Quantum Dots

2019 ◽  
Vol 5 (4) ◽  
pp. 68 ◽  
Author(s):  
Soriano ◽  
Cárdenas
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Fluorescence Emission ◽  
Waste Recycling ◽  
Primary Amines ◽  
Beta Lactam ◽  
Emerging Pollutant ◽  
Lactam Antibiotic ◽  
Potential Applications ◽  
Ir And Raman

Of great concern are the residual antibiotics from dirt that can be found in farm soil and wastewater. This kind of emerging pollutant into engineered nanomaterials is riveting. This work proposes the elimination and transformation of a beta-lactam antibiotic, oxacillin, from environmental waste to graphene quantum dots (GQDs). Two protocols were followed in which the use of ethylenediamine (EDA) in the transformation leads to GQDs with excellent optical properties. Therefore, two types of GQDs were synthesized in a Teflon-lined stainless autoclave by a thermal procedure using oxacillin in the absence and presence of EDA. The ensuing e-GQDs from oxacillin and EDA display a stronger fluorescence emission in comparison to those synthesized without EDA (o-GQDs). The combination of Kaiser test analyses, infrared (IR) and Raman measurements revealed the presence of oxygen-containing groups and primary amines at the edges of the graphitic nanolayer for e-GQDs. This straightforward strategy brings hope and opens a new interest in waste recycling by means of extracting residual contaminants from the environment for their further transformation into adequate non-toxic graphitic nanomaterials with potential applications.

scholarly journals The Synthesis and Application of Nitrogen-Doped Graphene Quantum Dots on Brilliant Blue Detection

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Li Jin ◽  
Ying Wang ◽  
Fengkai Yan ◽  
Jianpo Zhang ◽  
Fangli Zhong
Keyword(s):  
Quantum Dots ◽  
Emission Spectrum ◽  
Graphene Quantum Dots ◽  
Fluorescence Emission ◽  
Fluorescence Decay ◽  
Brilliant Blue ◽  
Fluorescence Emission Spectrum ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Nitrogen-doped graphene quantum dots had been successfully synthesized and characterized by using transmission electron microscope, X-ray photoelectron spectroscopy, absorbance spectrum, fluorescence emission spectrum, and fluorescence decay curve. TEM results indicated that the diameters of the as-prepared nitrogen-doped graphene quantum dots were in the range of 2 - 5 nm and the lattice space is about 0.276 nm; Raman spectrum result indicated that there were two characteristic peaks, generally named D (~1408 cm−1) and G (~1640 cm−1) bands; both TEM and Raman spectrum results indicated that the as-synthesized product was graphene quantum dots. Deconvoluted high resolution XPS spectra for C1s, O1s, and N1s results indicated that there are -NH-, -COOH, and -OH groups on the surface of nitrogen-doped graphene quantum dot. Fluorescence emission spectrum indicated that the maximum fluorescence emission spectrum of nitrogen-doped graphene quantum dots was blue shift about 30.1 nm and the average fluorescence decay time of nitrogen-doped graphene quantum dots increased about 2 ns, compared with graphene quantum dots without doping of nitrogen. Then, the as-prepared nitrogen-doped graphene quantum dots were used to quantitatively analyze brilliant blue based on the fluorescent quenching of graphene quantum dots, and the effect of pH and reaction time on this fluorescent quenching system was also obtained. Under selected condition, the linear regression equations were F0/F=0.0087 (brilliant blue) + 0.9553 and F0/F=0.01205 (brilliant blue) + 0.6695, and low detection limit was 3.776 μmol/L (3.776 nmol/mL). Once more diluted N-GQDs (0.05 mg/mL) were used, the low detection limit could reach 94.87 nmol/L. Then, temperature-dependent experiment, absorbance spectra, and dynamic fluorescence quenching rate constant were used to study the quenching mechanism; all results indicated that this quenching process was a static quenching process based on the formation of complex between nitrogen-doped graphene quantum dots and brilliant blue through hydrogen bond. Particularly, this method was used to quantitatively analyze the wine sample, of which results have a high consistence with the results of the spectrophotometric method; demonstrating this fluorescence quenching method could be used in practical sample application.

scholarly journals Metastable intermolecular composites of Al and CuO nanoparticles assembled with graphene quantum dots

RSC Advances ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 1718-1723 ◽  
Author(s):  
Yue Tao ◽  
Jiali Zhang ◽  
Yaoyao Yang ◽  
Haixia Wu ◽  
Lan Hu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Cuo Nanoparticles ◽  
Potential Applications ◽  
Metastable Intermolecular Composites

Metastable intermolecular composites (MICs) have attracted great attention during the last two decades owing to their potential applications for both civilian and military purposes.

White luminescent single-crystalline chlorinated graphene quantum dots

2020 ◽  
Vol 5 (6) ◽  
pp. 928-933 ◽  
Author(s):  
Weitao Li ◽  
Huazhang Guo ◽  
Gao Li ◽  
Zhen Chi ◽  
Hailong Chen ◽  
...  
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Graphene Quantum Dots ◽  
Luminescent Materials ◽  
Single Crystalline ◽  
Light Emitting ◽  
New Class ◽  
Potential Applications

A new class of white luminescent materials, white-light-emitting graphene quantum dots (WGQDs), have attracted increasing attention because of their unique features and potential applications.

Fabrication of graphene oxide decorated with nitrogen-doped graphene quantum dots and its enhanced electrochemiluminescence for ultrasensitive detection of pentachlorophenol

The Analyst ◽  
2015 ◽  
Vol 140 (4) ◽  
pp. 1253-1259 ◽  
Author(s):  
Xiaojiao Du ◽  
Ding Jiang ◽  
Qian Liu ◽  
Gangbing Zhu ◽  
Hanping Mao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Electrocatalytic Activity ◽  
Graphene Quantum Dots ◽  
Ultrasensitive Detection ◽  
Nitrogen Doped ◽  
New Class ◽  
Potential Applications ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Nitrogen-doped graphene quantum dots, as a new class of quantum dots, have potential applications in fuel cells and optoelectronics fields due to their electrocatalytic activity, tunable luminescence and biocompatibility.

A Critical Review of Graphene Quantum Dots: Synthesis and Application in Biosensors

NANO ◽  
2021 ◽  
pp. 2130001
Author(s):  
Jialu Shen ◽  
Weifeng Chen ◽  
Zihan Yang ◽  
Guo Lv ◽  
Jie Cao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Critical Review ◽  
Graphene Quantum Dots ◽  
Top Down ◽  
Bottom Up ◽  
Advantages And Disadvantages ◽  
Future Developments ◽  
Potential Applications

Graphene quantum dots (GQDs) have aroused widespread attention because of their remarkable properties and potential applications. Herein, we discuss both the top-down and bottom-up strategies for the synthesis of GQDs. Different processes are presented to study their characteristics and the influence on the final properties of GQDs. The respective advantages and disadvantages of these methods are summarized. With regard to some important or novel ones, mechanisms are proposed for reference. In addition, the application of GQDs in biosensors is highlighted in detail. At last, we put forward some problems to be solved and give a brief prospect in their future developments. This review is very useful for quickly gaining knowledge and experience for synthesizing GQDs and designing the related novel biosensors.

scholarly journals Beta-Lactam Antibiotic Discrimination Using a Macromolecular Sensor in Water at Neutral pH

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6384
Author(s):  
Yifei Xu ◽  
Marco Bonizzoni
Keyword(s):  
Fluorescence Emission ◽  
Spectroscopic Properties ◽  
World Market ◽  
Beta Lactam ◽  
Data Set ◽  
Linear Discriminant ◽  
Fifth Generation ◽  
Lactam Antibiotic ◽  
Cephalosporin Antibiotics ◽  
Hydrolysis Of

Penicillins and cephalosporins belong to the β-lactam antibiotic family, which accounts for more than half of the world market for antibiotics. Misuse of antibiotics harms human health and the environment. Here, we describe an easy, fast, and sensitive optical method for the sensing and discrimination of two penicillin and five cephalosporin antibiotics in buffered water at pH 7.4, using fifth-generation poly (amidoamine) (PAMAM) dendrimers and calcein, a commercially available macromolecular polyelectrolyte and a fluorescent dye, respectively. In aqueous solution at pH 7.4, the dendrimer and dye self-assemble to form a sensor that interacts with carboxylate-containing antibiotics through electrostatic interaction, monitored through changes in the dye’s spectroscopic properties. This response was captured through absorbance, fluorescence emission, and fluorescence anisotropy. The resulting data set was processed through linear discriminant analysis (LDA), a common pattern-base recognition method, for the differentiation of cephalosporins and penicillins. By pre-hydrolysis of the β-lactam rings under basic conditions, we were able to increase the charge density of the analytes, allowing us to discriminate the seven analytes at a concentration of 5 mM, with a limit of discrimination of 1 mM.

Fluorescent graphene quantum dots for biosensing and bioimaging

RSC Advances ◽  
2015 ◽  
Vol 5 (25) ◽  
pp. 19773-19789 ◽  
Author(s):  
Zetan Fan ◽  
Shuhua Li ◽  
Fanglong Yuan ◽  
Louzhen Fan
Keyword(s):  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Potential Applications

Graphene quantum dots with unique properties have great potential applications for biosensing and bioimaging.

scholarly journals Highly Fluorescent Nitrogen-Doped Graphene Quantum Dots’ Synthesis and Their Applications as Fe(III) Ions Sensor

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Fei Lu ◽  
Yi-hua Zhou ◽  
Li-hui Wu ◽  
Jun Qian ◽  
Sheng Cao ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Quantum Dots ◽  
Metal Ion ◽  
Graphene Quantum Dots ◽  
Fluorescence Emission ◽  
Blue Fluorescence ◽  
One Pot ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

Nitrogen-doped graphene quantum dots (N-GQDs) with strong blue fluorescence and a high quantum yield of 88.9% were synthesized via a facile one-pot hydrothermal treatment with citric acid (CA) and ethylenediamine (EDA) as carbon and nitrogen sources, respectively. The blue fluorescence emission is independent of the excitation wavelengths. These N-GQDs dispersed well in water and ethyl alcohol and showed a highly selective and sensitive detection of hazardous and toxic Fe3+in the range of 1600μmol/L to 6000μmol/L through a fluorescence quenching process with a detection limit of 2.37μmol/L. Based on the excellent sensitivity and selectivity of N-GQDs to heavy metal ions, paper-based sensors can be fabricated by inkjet printing, which are rapid but low cost. So the visual instant on-site identification of heavy metal ion will be realized in the future.

scholarly journals Electrochemical and Fluorescent Properties of Crown Ether Functionalized Graphene Quantum Dots for Potassium and Sodium Ions Detection

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2897
Author(s):  
Daniela Iannazzo ◽  
Claudia Espro ◽  
Angelo Ferlazzo ◽  
Consuelo Celesti ◽  
Caterina Branca ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Crown Ethers ◽  
Biological Fluids ◽  
Graphene Quantum Dots ◽  
Fluorescence Emission ◽  
Fluorescent Properties ◽  
Fluorescent Method ◽  
Basic Body ◽  
Emission Behavior ◽  
K Concentration

The concentration of sodium and potassium ions in biological fluids, such as blood, urine and sweat, is indicative of several basic body function conditions. Therefore, the development of simple methods able to detect these alkaline ions is of outmost importance. In this study, we explored the electrochemical and optical properties of graphene quantum dots (GQDs) combined with the selective chelating ability of the crown ethers 15-crown-5 and 18-crown-6, with the final aim to propose novel composites for the effective detection of these ions. The results obtained comparing the performances of the single GQDs and crown ethers with those of the GQDs-15-crown-5 and GQDs-18-crown-6 composites, have demonstrated the superior properties of these latter. Electrochemical investigation showed that the GQDs based composites can be exploited for the potentiometric detection of Na+ and K+ ions, but selectivity still remains a concern. The nanocomposites showed the characteristic fluorescence emissions of GQDs and crown ethers. The GQDs-18-crown-6 composite exhibited ratiometric fluorescence emission behavior with the variation of K+ concentration, demonstrating its promising properties for the development of a selective fluorescent method for potassium determination.

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