scholarly journals Flexible All-biomass Gas Sensor based on Doped Carbon Quantum Dots/nonwoven Cotton with Discriminative Function

2021 ◽  
Author(s):  
zhaofeng wu ◽  
Min Zhang ◽  
Shuai Cao ◽  
Long Wang ◽  
Zhangjie Qin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gas Sensor ◽  
High Sensitivity ◽  
Carbon Quantum Dots ◽  
Parameter Method ◽  
Hydrogen Bond Interaction ◽  
Target Analytes ◽  
Discriminative Function ◽  
Single Sensor ◽  
Multiple Analytes

Abstract Carbon quantum dots (CQDs) co-doped with N, P and S derived from expired milk was prepared by a simple hydrothermal method. Through the hydrogen bond interaction between CQDs and cellulose of pure cotton face towel (PCFT), CQDs were uniformly anchored on the cotton fibers to form a flexible all-biomass CQDs/PCFT sensor for the first time. Due to the heteroatom doping, extremely small particle size of CQDs and excellent permeability of CQDs/PCFT film, the flexible CQDs/PCFT sensor showed the high sensitivity and bending stability. In the range of 0 ~ 60o bending states, the responses of flexible CQDs/PCFT sensor to four target analytes changed by less 5%. Interestingly, due to the abundant functional groups and defects of CQDs, the flexible CQDs/PCFT sensor displayed sensing curves of different shapes for different target analytes. In this way, by establishing a database of sensing curves of target analytes, multiple analytes can be detected discriminatively by relying only on single sensor with the help of image recognition. In addition, the binary parameter method of response and response time was created, which also showed that a single sensor could achieve the discriminative detection. This work expanded the application of biomass CQDs and cellulose, and made a useful exploration for environment friendly flexible gas sensor.

Highly Fluorescent N-Doped Carbon Quantum Dots Derived from Bamboo Stems for Selective Detection of Fe3+ Ions in Biological Systems

2021 ◽  
Vol 17 (2) ◽  
pp. 312-321
Author(s):  
Jiamin Yan ◽  
Yuneng Lu ◽  
Shaowen Xie ◽  
Haihu Tan ◽  
Weilan Tan ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Biological Systems ◽  
High Sensitivity ◽  
Carbon Quantum Dots ◽  
Clinical Diagnostics ◽  
Quenching Effect ◽  
Biologically Relevant ◽  
Sensing Platform ◽  
Wide Ph Range ◽  
High Fluorescence

The establishment of sensing platform for trace analysis of Fe3+ in biological systems is meaningful for health monitoring. Herein, a Fe3+ sensitive fluorescent nanoprobe was constructed based on highly fluorescent N-doped carbon quantum dots (NCQDs) derived from bamboo stems through a hydrothermal method employing ethylenediamine as the nitrogen dopant. The prepared NCQDs had a uniformly distributed size and their mean size was around 2.43 nm. Abundant functional groups (C=N, N-H, C=O, and carboxyl) anchored on NCQDs demonstrated successful doping of N in CQDs. The obtained NCQDs possessed a high fluorescence quantum yield of 20.02% and outstanding fluorescence stability over a wide pH range and at high ionic strengths. Moreover, Fe3+ ions presented a specific fluorescent quenching effect to the as-prepared NCQDs. The calibration curve for fluorescence quenching degree corresponding to Fe3+ concentration showed a linear response in a range of 0.01–10 µM, and detection limit was 0.486 µM, which indicated that the NCQDs had high sensitivity to Fe3+ ions. Ascribed to these unique properties, the NCQDs were selected as luminescent probes for trace amount of Fe3+ ions in human serum. These results demonstrated their promising use in clinical diagnostics and other biologically relevant studies.

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.

scholarly journals Green Synthesis of SnO2/Carbon Quantum Dots Nanocomposite for Gas Sensing Application

2021 ◽  
Vol 8 (7) ◽  
pp. 332-336
Author(s):  
Hare Narayan Prajapati ◽  
Pradeep Kumar Khiriya ◽  
Gagan Kant Tripathi
Keyword(s):  
Quantum Dots ◽  
Green Synthesis ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Sno2 Nanoparticles ◽  
Carbon Quantum Dots ◽  
Optimum Operating ◽  
Grape Fruit ◽  
Different Temperatures ◽  
Grape Fruit Juice

SnO2/Carbon Quantum Dots (CQDs) were synthesized by a hydrothermal method using grape fruit juice. The nanocomposites (NC) were characterized by means of XRD and Gas sensing properties. The sensor devices were fabricated using SnO2/CQDs NC as sensing materials. The effect of the CQDs content on the gas-sensing responses and the gas-sensing selectivity was investigated. In this work, the gas sensor developed is exposed to carbon monoxide polluting gas like at different temperatures to determine the optimum operating temperatures which allow obtaining the highest sensitivity for gas. Keywords: Green synthesis, Grape fruit, SnO2 nanoparticles, CQDs, Gas sensor.

A Green, Economic “Switch-On” Sensor for Cefixime Analysis Based on Black Soya Bean Carbon Quantum Dots

2020 ◽  
Vol 103 (5) ◽  
pp. 1230-1236
Author(s):  
Yuecheng Zhang ◽  
Jingyuan Wang ◽  
Wenbo Wu ◽  
Chengjia Li ◽  
Hongyan Ma
Keyword(s):  
Quantum Dots ◽  
Bacterial Infections ◽  
Low Cost ◽  
High Sensitivity ◽  
Practical Method ◽  
Carbon Quantum Dots ◽  
Drug Analysis ◽  
Soya Bean ◽  
Simple Strategy ◽  
Biological Environment

Abstract Background Cefixime is a third-generation oral cephalosporin antibiotic widely used to treat bacterial infections. Typical methods for cefixime analysis use expensive instruments or sophisticated experimental procedures, and thus a sensitive and practical method is urgently needed for cefixime detection and analysis. Objective To develop a sensitive and robust cefixime “switch-on” sensor based on carbon quantum dots (CQDs). Methods In this study, black soya beans were used as an inexpensive carbon source for a “green” synthesis of fluorescent black soya bean (BS)-carbon quantum dots (CQDs). The fluorescence of these particles could be efficiently quenched by Ce(IV)due to the ground state recombination and electron transfer (ET) between Ce(IV)and BS-CQDs. In the presence of cefixime, the ET was interrupted and the fluorescent signal was recovered. Results/Conclusions This method showed high sensitivity and an impressively low detection limit of 169 nM. Highlights This low-cost, simple strategy for cefixime detection exhibits excellent stability, selectivity, and sensitivity. Moreover, it was successfully applied for the detection of cefixime in tablets and in a complex biological environment, confirming its great potential utility for drug analysis, biological process research, and clinical research.

Zero-dimensional heterostructures: N-doped graphene dots/SnO2 for ultrasensitive and selective NO2 gas sensing at low temperatures

2020 ◽  
Vol 8 (23) ◽  
pp. 11734-11742
Author(s):  
Rahul Purbia ◽  
Yeong Min Kwon ◽  
Hong-Dae Kim ◽  
Yun Sik Lee ◽  
Heungjoo Shin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gas Sensor ◽  
Low Temperatures ◽  
Gas Sensing ◽  
Graphene Quantum Dots ◽  
High Sensitivity ◽  
Facile Synthesis ◽  
Doped Graphene ◽  
Excellent Selectivity

Facile synthesis of zero-dimensional heterostructures consisting of N-doped graphene quantum dots (N-GDs) and SnO2 nanoparticles is reported for the NO2 gas sensor with high sensitivity and excellent selectivity.

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.

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