scholarly journals Synthesis of Copper–nitrogen Codoped Carbon Quantum Dots Using Frangipani as a Carbon Source and Application of Metronidazole Determination

Author(s):  
Lan Yuwei Lan ◽  
Yuwei Lan ◽  
Wenbin Bao ◽  
Chunfeng Liang ◽  
Guowei Li ◽  
...  

Abstract High-fluorescence Cu/N codoped carbon quantum dots (Cu/NCQDs) were prepared by a one-step hydrothermal method using frangipani as the carbon source and copper acetate as the copper source. The Cu/NCQDs exhibited high-intensity, stable blue fluorescence that is independent of the excitation wavelength. Since metronidazole can effectively quench the fluorescence intensity of Cu/NCQDs, a metronidazole fluorescence-detection method using Cu/NCQDs as the fluorescence probe was developed, and the quenching mechanism was studied.The method has the advantages of simplicity, speed, and low cost. Besides,it has a wider linear range and detection limit. Further, the metronidazole content in actual samples was determined by this method, with good results.

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 616 ◽  
Author(s):  
Xi Wang ◽  
Pei Yang ◽  
Qian Feng ◽  
Taotao Meng ◽  
Jing Wei ◽  
...  

Biomass-based carbon quantum dots (CQDs) have become a significant carbon materials by their virtues of being cost-effective, easy to fabricate and low in environmental impact. However, there are few reports regarding using cyanobacteria as a carbon source for the synthesis of fluorescent CQDs. In this study, the low-cost biomass of cyanobacteria was used as the sole carbon source to synthesize water-soluble CQDs by a simple hydrothermal method. The synthesized CQDs were mono-dispersed with an average diameter of 2.48 nm and exhibited excitation-dependent emission performance with a quantum yield of 9.24%. Furthermore, the cyanobacteria-derived CQDs had almost no photobleaching under long-time UV irradiation, and exhibited high photostability in the solutions with a wide range of pH and salinity. Since no chemical reagent was involved in the synthesis of CQDs, the as-prepared CQDs were confirmed to have low cytotoxicity for PC12 cells even at a high concentration. Additionally, the CQDs could be efficiently taken up by cells to illuminate the whole cell and create a clear distinction between cytoplasm and nucleus. The combined advantages of green synthesis, cost-effectiveness and low cytotoxicity make synthesized CQDs a significant carbon source and broaden the application of cyanobacteria and provide an economical route to fabricate CQDs on a large scale.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Cuo Zhou ◽  
Shunwei Wu ◽  
Shenghui Qi ◽  
Weijun Song ◽  
Chunyan Sun

Hydrothermal synthesis of carbon quantum dots (CQDs) from natural biomass is a green and sustainable route for CQDs applications in various fields. In this work, the preparation and characterization of CQDs based on quinoa saponin were investigated. The optimum synthetic conditions determined by orthogonal experiments were as follows: 2 g quinoa saponin powder and 0.04 mol ethylenediamine reacted at 200°C for 10 h. The relative fluorescence quantum yield (QY = 22.2%) can be obtained, which is higher than some results reported in the literatures. The prepared CQDs had a small and uniform size (∼2.25 nm) and exhibited excitation wavelength-dependent blue light emission behavior. The CQDs displayed excellent sensitivity for Co2+ detection along with good linear correlation ranging from 20 to 150 µM and the detection limit of 0.49 µM. The CQDs prepared in this experiment were successfully implanted into soybean sprouts for fluorescence imaging. The sprouts could grow healthily even soaked in the CQDs solution for two weeks, demonstrating the low toxicity of the CQDs. The advantages of the CQDs, such as low cost, ease of manufacture, nontoxicity, and stability, have potential applications in many areas such as metal ion detection and biosensing.


MRS Advances ◽  
2016 ◽  
Vol 1 (19) ◽  
pp. 1371-1376 ◽  
Author(s):  
George R. S. Andrade ◽  
Silvânio S. L. Costa ◽  
Cristiane C. Nascimento ◽  
Iara F. Gimenez

ABSTRACTIn this work, 3 simple, fast, labour and energy efficient methodologies were used to prepare carbon quantum dots (C-dots) using a red beetroot (Beta vulgaris subsp. vulgaris var. vulgaris) aqueous extract as the carbon source: alkali-assisted (AA), microwave-assisted (MA) and alkali-microwave-assisted (AMA) synthesis. TEM images shows nanoparticles with a nearly spherical morphology and diameters around 7.0 nm. FTIR spectra show characteristic peaks of C-H, C-O, O-H and C=C bonds for all the samples. The emission spectra show an interesting feature of the as-prepared samples: the emission band position can be tunable by changing the excitation wavelength. Comparing the 3 different methodologies in terms of photoluminescence properties, the one based only on the microwave-assisted heating has showed the most improved emission.


2017 ◽  
Vol 41 (21) ◽  
pp. 13130-13139 ◽  
Author(s):  
S. Solomon Jones ◽  
Parikshit Sahatiya ◽  
Sushmee Badhulika

In this work, we demonstrate the high-yield synthesis of carbon quantum dots using a one-step eco-friendly, low-cost thermal treatment of a renewable biomass, i.e. natural chia seeds.


RSC Advances ◽  
2021 ◽  
Vol 11 (16) ◽  
pp. 9121-9129
Author(s):  
Sujuan Zhu ◽  
Xuexue Bai ◽  
Ting Wang ◽  
Qiang Shi ◽  
Jing Zhu ◽  
...  

This study proposes an easy bottom-up method for the synthesis of photoluminescent (PL) graphene quantum dots (GQDs) using citric acid as the carbon source.


2016 ◽  
Vol 4 (14) ◽  
pp. 2412-2420 ◽  
Author(s):  
Aneeya K. Samantara ◽  
Santanu Maji ◽  
Arnab Ghosh ◽  
Bamaprasad Bag ◽  
Rupesh Dash ◽  
...  

A facile one-step approach has been developed for the synthesis of carbon quantum dots (CQDs) from Good’s buffer.


Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 538
Author(s):  
Pengpeng Ren ◽  
Wenfei Zhang ◽  
Yiqun Ni ◽  
Di Xiao ◽  
Honghao Wan ◽  
...  

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) quantum dots (QDs) are the vanguard due to their unique properties. In this work, WSe2 QDs were fabricated via one step ultrasonic probe sonication. Excitation wavelength dependent photoluminescence (PL) is observed from WSe2 QDs. Room-temperature lasing emission which benefits from 3.7 times enhancement of PL intensity by thermal treatment at ~470 nm was achieved with an excitation threshold value of ~3.5 kW/cm2 in a Fabry–Perot laser cavity. To the best of our knowledge, this is the first demonstration of lasing emission from TMDCs QDs. This indicates that TMDCs QDs are a superior candidate as a new type of laser gain medium.


Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 438 ◽  
Author(s):  
Manyu Shao ◽  
Ming Yao ◽  
Sarah De Saeger ◽  
Liping Yan ◽  
Suquan Song

An eco-friendly and efficient one-step approach for the synthesis of carbon quantum dots (CDs) that encapsulated molecularly imprinted fluorescence quenching particles (MIFQP) and their application for the determination of zearalenone (ZEA) in a cereal sample are described in this study. CDs with high luminescence were first synthesized, and then encapsulated in the silica-based matrix through a non-hydrolytic sol-gel process. The resulting ZEA-imprinted particles exhibited not only an excellent specific molecular recognition of ZEA, but also good photostability and obvious template binding-induced fluorescence quenching. Under the optimized conditions, the fluorescence intensity of MIFQP was inversely proportional to the concentration of ZEA. By validation, the detection range of these fluorescence quenching materials for ZEA was between 0.02 and 1.0 mg L−1, and the detection limit was 0.02 mg L−1 (S/N = 3). Finally, the MIFQP sensor was successfully applied for ZEA determination in corn with recoveries from 78% to 105% and the relative standard deviation (RSD %) was lower than 20%, which suggests its potential in actual applications.


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