Synthesis of Fluorescent Nitrogen-Doped Carbon Quantum Dots for Selective Detection of Picric Acid in Water Samples

2018 ◽  
Vol 18 (12) ◽  
pp. 8111-8117 ◽  
Author(s):  
Min Tian ◽  
Yingte Wang ◽  
Yong Zhang
Keyword(s):  
Fluorescence Quenching ◽  
Fluorescence Probe ◽  
Picric Acid ◽  
Fluorescence Emission ◽  
Excitation Wavelength ◽  
Selective Detection ◽  
Blue Fluorescence ◽  
Nitrogen Doped ◽  
Relative Standard ◽  
Nitrogen Doped Carbon

In this work, fluorescent nitrogen-doped carbon dots (N-CDs) were pyrolysis synthesized using edetic acid and acrylamide as precursors without further surface modication. The as-prepared N-CDs were mono-dispersed spherical nanoparticles with an average diameter of 3.25 nm. The blue fluorescence emission was dependent of the excitation wavelengths, releasing stable and strong blue fluorescence under the maximum excitation wavelength. More strikingly, after adding picric acid (PA), the fluorescence of N-CDs aqueous solution gave rise to the obviously fluorescence quenching due to the inner filter effect. Under the optimum conditions, the fluorescence probe can be used for the selective detection of PA with a wide linear relationship in the range of 0.01–32 μM and the detection as low as 0.046 μM. Depending on the fluorescence quenching phenomenon, the resultant fluorescent probe for accurate and selective monitor of PA in Fenhe river samples was explored. The recoveries fell in the range of 97.13%–106.21% and the relative standard deviation was below 3% with satisfactory results.

A Novel Near-Infrared Fluorescence Sensor for H2O2 Based on N-Acetyl-L-Cysteine-Capped Gold Nanoparticles

2017 ◽  
Vol 46 ◽  
pp. 234-240
Author(s):  
Wen Juan Dong ◽  
Ji Yan Han ◽  
Xin Wu ◽  
Li Fan ◽  
Wen Ting Liang
Keyword(s):  
Hydrogen Peroxide ◽  
Gold Nanoparticles ◽  
Fluorescence Quenching ◽  
Near Infrared ◽  
Fluorescence Probe ◽  
Fluorescence Emission ◽  
Excitation Wavelength ◽  
Experimental Conditions ◽  
Time Resolved ◽  
Near Infrared Fluorescence

A novel near-infrared fluorescence quenching method has been developed for the determination of hydrogen peroxide based on N-acetyl-L-cysteine-capped gold nanoparticles (NAC-AuNPs) as a fluorescence probe. The prepared gold nanoparticles with the size of about 1.91 nm exhibited strong near-infrared fluorescence emission at 693 nm with excitation wavelength at 450 nm in aqueous solution. The fluorescence intensity of NAC-AuNPs was quenched dramatically by adding hydrogen peroxide. Therefore, it could be used to detect hydrogen peroxide based on the fluorescence quenching intensity was linear with the concentration of hydrogen peroxide. Under the optimal experimental conditions, the linear range and detection limit were 1.0×10-6 –3.0×10-2 mol/L and 1.0×10-7 mol/L, respectively. The possible quenching mechanism was investigated by time-resolved fluorescence spectroscopy. The proposed method was simple, sensitive and showed good repeatability and stability.

Facile one-step synthesis and fluorescence performance study of nitrogen-doped carbon quantum dots

2021 ◽  
Vol 14 (02) ◽  
pp. 2150009
Author(s):  
Xu Huai ◽  
Weiwei Duan ◽  
Jiayu Li ◽  
Qin Zhang ◽  
Qian Dong ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Nitrogen Concentration ◽  
Carbon Sources ◽  
Fluorescence Emission ◽  
Carbon Quantum Dots ◽  
Performance Study ◽  
Blue Fluorescence ◽  
Nitrogen Doped ◽  
One Step ◽  
Nitrogen Doped Carbon

A facile strategy is reported to synthesize nitrogen-doped carbon quantum dots (N-CQDs) with fluorescence emission by a one-step hydrothermal treatment under different temperatures with dicyanodiamide and citric acid as precursor materials of nitrogen and carbon sources, respectively. The as-produced N-CQDs display green or blue fluorescence under the ultraviolet lamp was controlled by the reaction temperature. Consequently, the as-prepared sample reacted at 200[Formula: see text]C (N-CQDs-200), within the range of 3 nm, exhibits blue fluorescence excited at 365 nm irradiation with the maximum quantum yield (QY) of ca. 30.6%. Moreover, the N-CQDs possess rich functional groups such as nitrous groups and multiple oxygenated groups, which result in a favorable solubility in most hydrophilic solvents. From the characterization and discussion of TEM, HRTEM, FT-IR, XPS, Raman and UV-Vis, it is illustrated that the fluorescence performance was largely related to the nanomorphology, nitrogen concentration, multi-surface emission sites and various forms of transitions derived from the nitrogen doping. With the excellent fluorescence performance and the favorable solubility in solvents, the products are potentially suitable for monitoring organics.

scholarly journals A Facile Synthesis of Highly Nitrogen-Doped Carbon Dots for Imaging and Detection in Biological Samples

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Qianchun Zhang ◽  
Siqi Xie ◽  
Yanqun Yang ◽  
Yun Wu ◽  
Xingyi Wang ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Probe ◽  
Fluorescence Emission ◽  
Carbon Quantum Dots ◽  
Nitrogen Doped ◽  
Low Toxicity ◽  
High Fluorescence ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

A facile, green, and high-output hydrothermal synthesis was proposed for the fabrication of highly fluorescent nitrogen-doped carbon quantum dots (N-doped CDs). The nitrogen content in N-doped CDs reached 19.2% and demonstrated strong blue fluorescence emission was obtained with fluorescence quantum yield (QY) of up to 32.9%, which exhibit high fluorescence quantum yield, high photostability, and excellent biocompatibility. The N-doped CDs possess high photostability, low toxicity, and excellent biocompatibility, based on which the N-doped CDs were successfully applied as a fluorescence probe for cell imaging. Moreover, it was then successfully demonstrated for sensitive and selective detection of Fe3+ in serum.

A Bright Nitrogen-doped-Carbon-Dots based Fluorescent Biosensor for Selective Detection of Copper Ions

2021 ◽  
Vol 5 (1) ◽  
pp. 84-92
Author(s):  
Shuting Chen ◽  
Chaoqun Chen ◽  
Jian Wang ◽  
Fang Luo ◽  
Longhua Guo ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Copper Ions ◽  
Selective Detection ◽  
Nitrogen Doped ◽  
Fluorescent Biosensor ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

scholarly journals Synthesis and Properties of Nitrogen-Doped Carbon Quantum Dots Using Lactic Acid as Carbon Source

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 466
Author(s):  
Kaixin Chang ◽  
Qianjin Zhu ◽  
Liyan Qi ◽  
Mingwei Guo ◽  
Woming Gao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Lactic Acid ◽  
Fluorescence Quenching ◽  
Functional Groups ◽  
Fluorescence Intensity ◽  
Carbon Quantum Dots ◽  
Nitrogen Doped ◽  
Ph Values ◽  
Wide Range ◽  
Nitrogen Doped Carbon

Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in a one-step hydrothermal technique utilizing L-lactic acid as that of the source of carbon and ethylenediamine as that of the source of nitrogen, and were characterized using dynamic light scattering, X-ray photoelectron spectroscopy ultraviolet-visible spectrum, Fourier-transformed infrared spectrum, high-resolution transmission electron microscopy, and fluorescence spectrum. The generated N-CQDs have a spherical structure and overall diameters ranging from 1–4 nm, and their surface comprises specific functional groups such as amino, carboxyl, and hydroxyl, resulting in greater water solubility and fluorescence. The quantum yield of N-CQDs (being 46%) is significantly higher than that of the CQDs synthesized from other biomass in literatures. Its fluorescence intensity is dependent on the excitation wavelength, and N-CQDs release blue light at 365 nm under ultraviolet light. The pH values may impact the protonation of N-CQDs surface functional groups and lead to significant fluorescence quenching of N-CQDs. Therefore, the fluorescence intensity of N-CQDs is the highest at pH 7.0, but it decreases with pH as pH values being either more than or less than pH 7.0. The N-CQDs exhibit high sensitivity to Fe3+ ions, for Fe3+ ions would decrease the fluorescence intensity of N-CQDs by 99.6%, and the influence of Fe3+ ions on N-CQDs fluorescence quenching is slightly affected by other metal ions. Moreover, the fluorescence quenching efficiency of Fe3+ ions displays an obvious linear relationship to Fe3+ concentrations in a wide range of concentrations (up to 200 µM) and with a detection limit of 1.89 µM. Therefore, the generated N-CQDs may be utilized as a robust fluorescence sensor for detecting pH and Fe3+ ions.

scholarly journals Green Preparation of Fluorescent Nitrogen-Doped Carbon Quantum Dots for Sensitive Detection of Oxytetracycline in Environmental Samples

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1561
Author(s):  
Rong Gao ◽  
Zhibin Wu ◽  
Li Wang ◽  
Jiao Liu ◽  
Yijun Deng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Tap Water ◽  
Orange Peel ◽  
Carbon Quantum Dots ◽  
Sensitive Detection ◽  
Biomass Waste ◽  
Visible Absorption ◽  
Nitrogen Doped ◽  
Relative Standard ◽  
Nitrogen Doped Carbon

Nitrogen-doped carbon quantum dots (N-CQDs) with strong fluorescence were prepared by a one-step hydrothermal method using natural biomass waste. Two efficient fluorescent probes were constructed for selective and sensitive detection of oxytetracycline (OTC). The synthesized N-CQDs were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FT-IR), X-ray photon spectroscopy (XPS), atomic force microscopy (AFM), and high-resolution transmission electron microscopy (HRTEM), which proved that the synthesized N-CQDs surface were functionalized and had stable fluorescence performance. The basis of N-CQDs detection of OTC was discussed, and various reaction conditions were studied. Under optimized conditions, orange peel carbon quantum dots (ON-CQDs) and watermelon peel carbon quantum dots (WN-CQDs) have a good linear relationship with OTC concentrations in the range of 2–100 µmol L−1 and 0.25–100 µmol L−1, respectively. ON-CQDs and WN-CQDs were both successfully applied in detecting the OTC in pretreated tap water, lake water, and soil, with the recovery rate at 91.724–103.206%, and the relative standard deviation was less than 5.35%. The results showed that the proposed N-CQDs proved to be green and simple, greatly reducing the detection time for OTC in the determination environment.

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