scholarly journals One-Pot Hydrothermal Synthesis of Carbon Dots as Fluorescent Probes for the Determination of Mercuric and Hypochlorite Ions

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1831
Author(s):  
Hsin Lee ◽  
Yen-Chang Su ◽  
Hsiang-Hao Tang ◽  
Yu-Sheng Lee ◽  
Jan-Yee Lee ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Fluorescent Probes ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Tap Water ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Excitation Wavelength ◽  
One Pot ◽  
Fluorescence Emission Spectra

Nitrogen and sulfur codoped carbon dots (NSCDs) were synthesized via a one-pot hydrothermal method, and citric acid, ethylenediamine, and methyl blue were used as precursors. The obtained NSCDs were spherical with an average size of 1.86 nm. The fluorescence emission spectra of the NSCDs were excitation independent and emitted blue fluorescence at 440 nm with an excitation wavelength at 350 nm. The quantum yield of the NSCDs was calculated to be 68.0%. The NSCDs could be constructed as fluorescent probes for highly selective and sensitive sensing mercuric (Hg2+) and hypochlorite (ClO−) ions. As the addition of Hg2+ or ClO− ions to the NSCDs, the fluorescence intensity was effectively quenched due to dynamic quenching. Under the optimal conditions, the linear response of the fluorescence intensity ranged from 0.7 μM to 15 μM with a detection limit of 0.54 μM and from 0.3 μM to 5.0 μM with a limit of detection of 0.29 μM for Hg2+ and ClO− ions, respectively. Finally, the proposed method was successfully used for quantifying Hg2+ and ClO− ions in spiked tap water samples.

scholarly journals Spectrofluorimetric Determination of Hydrochlorothiazide by a Carbon Dots-Based Probe via Inner Filtering Effect and Resonance Rayleigh Scattering

2022 ◽  
Author(s):  
Ali Ghafarloo ◽  
Reza Sabzi ◽  
Naser Samadi ◽  
Hamed Hamishehkar
Keyword(s):  
Carbon Dots ◽  
Rayleigh Scattering ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Emission Spectra ◽  
Cost Effective ◽  
Inner Filter Effect ◽  
Resonance Rayleigh Scattering ◽  
Excitation Spectra ◽  
One Pot

Synthesis of carbon dots (CDs) from natural resources not only enables green synthesis and production of environmentally friendly materials, but also provides a cost-effective probe as a fluorescence nanosensor. The proposed sensor introduces a unique one-pot hydrothermal CDs synthesis from alfalfa leaves, which is promising for sensing hydrochlorothiazide (HCTZ) via inner filter effect (IFE) and resonance Rayleigh scattering (RRS). The as-prepared CDs had wide emission spectra, excitation-dependent emission, high solubility, high stability, and visible fluorescence light with a quantum yield of up to 11%. The absorption of HCTZ overlapped with the excitation spectra of CDs. Therefore, CDs represented excellent quenching due to IFE when HCTZ was gradually added. Furthermore, this fluorescent sensor was successfully used to quantify HCTZ in the linear ranges (0.17-2.50 μg mL-1) with the limit of detection of 0.11 μg mL-1. The sensing system was simple as no surface functionalization was required for CDs, leading to less laborious steps and more cost-effective synthesis. The reaction time was short, i.e., less than 2 min, indicating a simple approach for rapid analysis of HCTZ. By optimizing conditions, successful measurements were carried out on pharmaceutical tablets.

Multiple excitation wavelength fluorescence emission spectra technique for discrimination of phytoplankton

2010 ◽  
Vol 9 (1) ◽  
pp. 16-24 ◽  
Author(s):  
Xupeng Hu ◽  
Rongguo Su ◽  
Fang Zhang ◽  
Xiulin Wang ◽  
Hongtao Wang ◽  
...  
Keyword(s):  
Fluorescence Emission ◽  
Emission Spectra ◽  
Excitation Wavelength ◽  
Fluorescence Emission Spectra

scholarly journals A Coumarin-Based Fluorescence Probe for Selective Recognition of Cu2+ Ions and Live Cell Imaging

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Guangjie He ◽  
Nana Ma ◽  
Linlin Li ◽  
Chenyan Xie ◽  
Linlin Yang ◽  
...  
Keyword(s):  
Live Cell Imaging ◽  
Density Functional ◽  
Fluorescence Probe ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Functional Theory ◽  
Photochemical Properties ◽  
Fluorescence Titrations

A new fluorescence probe L was rationally designed and synthesized for the recognition of Cu2+ ions by the combination of coumarin hydrazide and 2-acetylpyrazine. The photochemical properties and selectivity of L for Cu2+ ions in a CH3CN/HEPES (3 : 2, v/v) buffer were investigated by UV-vis absorption and fluorescence emission spectra. A highly selective and sensitive response of L for Cu2+ ions over other competing metal ions was observed with limit of detection in 3 μM. The coordination stoichiometry of L to Cu2+ ions was determined to be 1 : 1 by the UV-vis absorption spectrum, the fluorescence titrations, and density functional theory (DFT) calculations. Moreover, L was applied successfully for recognition of intracellular Cu2+ ions in living cells.

L-Histidine Stabilized Copper Nanoclusters as a Fluorescence Probe for Determination of Fluazinam

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050063
Author(s):  
Zhifeng Cai ◽  
Xiu Yin ◽  
Jingling Fang ◽  
Jie Zhao ◽  
Tianqi Wu ◽  
...  
Keyword(s):  
Fluorescence Intensity ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Fluorescence Probe ◽  
Synthesis Method ◽  
Fluorescence Emission ◽  
Average Diameter ◽  
High Dispersion ◽  
Excitation Wavelength ◽  
One Pot

In this contribution, a one-pot synthesis method possessing the advantages of simple, green and low-cost had been researched for the preparation of L-histidine-stabilized Cu nanoclusters (Cu NCs). Subsequently, the structure and optical properties of as-prepared Cu NCs were studied by using Fourier transform infrared (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy and UV-Vis absorption spectroscopy. TEM image of the Cu NCs showed high dispersion with an average diameter of 2.0[Formula: see text]nm. Fluorescence spectrum displayed that the Cu NCs emitted green fluorescence (emission wavelength of 492[Formula: see text]nm) under excitation wavelength of 393[Formula: see text]nm. Moreover, the as-synthesized Cu NCs illustrated excellent performances, such as good water solubility, UV stability and high-salt resistance. Interestingly, the fluorescence intensity of as-prepared Cu NCs was obviously quenched in the presence of fluazinam. Under optimal conditions, the relative fluorescence intensity was linear with the fluazinam concentrations from 1 to 40[Formula: see text][Formula: see text]M, with a detection limit of 0.25[Formula: see text][Formula: see text]M. Eventually, the fluorescence sensor was successfully used to determine fluazinam in real water samples.

A Novel Fluorescent Nanoswitch Based on Carbon Dots for Sensitive Detection of Hg2+ and I−

NANO ◽  
2017 ◽  
Vol 12 (02) ◽  
pp. 1750024 ◽  
Author(s):  
Xiqing Liu ◽  
Xiao Wei ◽  
Yeqing Xu ◽  
Hongji Li ◽  
Kai Lu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Fluorescence Intensity ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Hydrothermal Process ◽  
Fluorescence Emission ◽  
Selective Determination ◽  
Fluorescence Switching ◽  
Interfering Ions

In this paper, a novel fluorescent nanoswitch based on carbon dots (CDs) was developed for the sensitive and selective determination of Hg[Formula: see text] and I[Formula: see text]. The CDs were obtained by simple hydrothermal process and had a strong fluorescence emission at 440[Formula: see text]nm. The fluorescence of the CDs can be selectively quenched by Hg[Formula: see text] ion, and then the I[Formula: see text] was added into the system, which can interact with Hg[Formula: see text] and recover fluorescence of the CDs. Under optimal conditions, the quenching fluorescence intensity on addition of Hg[Formula: see text] has obtained a satisfactory linear relationship covering the linear range of 0–50[Formula: see text][Formula: see text]M with the linear relationship ([Formula: see text]), and the limit of detection is 0.047[Formula: see text][Formula: see text]M. The additions of I[Formula: see text] could lead to the fluorescence intensity of the solution of CDs and Hg[Formula: see text] (50[Formula: see text][Formula: see text]M) recover rapidly, which is linearly related ([Formula: see text]) to the concentration of I[Formula: see text] in the range from 0 to 70[Formula: see text][Formula: see text]M, the detection limit for I[Formula: see text] was calculated to be 0.084[Formula: see text][Formula: see text]M. Moreover, the developed method to detect Hg[Formula: see text] and I[Formula: see text] was evaluated in real examples, and the fluorescence switching can sensitively and selectively detect Hg[Formula: see text] and I[Formula: see text] over some potentially interfering ions, the recoveries were up to 97.8–107.0% and 96.7–106.6%, respectively.

scholarly journals Quantitative fluorescence spectrophotometry of acridine orange-stained unfixed cells. Potential for automated detection of human uterine cancer.

1976 ◽  
Vol 24 (1) ◽  
pp. 315-321 ◽  
Author(s):  
J F Golden ◽  
S S West ◽  
C K Echols ◽  
H M Shingleton
Keyword(s):  
Acridine Orange ◽  
Fluorescence Intensity ◽  
Uterine Cancer ◽  
Female Genital Tract ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Cell Types ◽  
Fluorescence Emission Spectra ◽  
Acid Complex ◽  
Normal Cells

After staining with acridine orange (AO), the nuclei of unfixed cells from the human female genital tract exhibited the same fluorescence behavior previously observed for human and murine leukocytes and mouse ascites tumor cells. With staining conditions chosen to assure saturation of the green-fluorescing AO-nucleic acid complex in normal cells, corrected fluorescence emission spectra were recorded from the entire nucleus of 341 cells taken from 32 normal and 28 abnormal patients. Intensity of the recorded spectra was expressed in phosphor particle units, a fixed arbitrary unit of fluorescence intensity, to display intensity differences among the spectra from the various cell types. In all abnormal samples, one or more cells were found with 530-nm nuclear fluorescence intensity considerably greater than the maximum intensity recorded from normal cells. Determination of the adequacy of 530-nm nuclear fluorescence intensity as a criterion for cancer detection requires additional investigation. Additional criteria, if needed, may be supplied by the metachromasy of AO-stained unfixed cells.

scholarly journals Design and Synthesis of a Fluorescent Probe Based on Copper Complex for Selective Detection of Hydrogen Sulfide

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Guanglan Mao ◽  
Chenxi Liu ◽  
Nan Yang ◽  
Linlin Yang ◽  
Guangjie He
Keyword(s):  
Density Functional ◽  
Fluorescence Probe ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Functional Theory ◽  
Design And Synthesis ◽  
Sequential Recognition ◽  
Coordination Configuration

A novel fluorescence probe NA-LCX was rationally designed and synthesized for the sequential recognition of Cu2+ and H2S by the combination of hydroxyl-naphthalene and diformylphenol groups. The response properties of NA-LCX for Cu2+ ions and H2S with “on-off-on” manner were investigated by fluorescence emission spectra. A highly selective and sensitive response of complex NA-LCX-Cu2+ for H2S over other competing amino acids was observed with a limit of detection at 2.79 μM. The stoichiometry of NA-LCX toward Cu2+ ions was determined to be 1 : 1 by the UV-Vis absorption spectrum, and the coordination configuration was calculated by density functional theory (DFT) calculations. Moreover, probe NA-LCX was applied successfully for the recognition of Cu2+ ions and H2S in living cells.

scholarly journals Sponge-derived Ageladine A affects the in vivo fluorescence emission spectra of microalgae

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242464
Author(s):  
Carolin Peter ◽  
Silke Thoms ◽  
Florian Koch ◽  
Franz Josef Sartoris ◽  
Ulf Bickmeyer
Keyword(s):  
Natural Products ◽  
Fluorescence Intensity ◽  
Crucial Role ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Emission Spectra ◽  
Tisochrysis Lutea ◽  
Emission Maximum ◽  
Ph Dependent

In several marine hosts of microalgae, fluorescent natural products may play an important role. While the ecological function of these compounds is not well understood, an interaction of these molecules with the photosynthesis of the symbionts has been suggested. In this study, the effect of Ageladine A (Ag A), a pH-dependent fluorophore found in sponges of the genus Agelas, on microalgal fluorescence was examined. The spectra showed an accumulation of Ag A within the cells, but with variable impacts on fluorescence. While in two Synechococcus strains, fluorescence of phycoerythrin increased significantly, the fluorescence of other Synechococcus strains was not affected. In four out of the five eukaryote species examined, chlorophyll a (Chl a) fluorescence intensity was modulated. In Tisochrysis lutea, for example, the position of the fluorescence emission maximum of Chl a was shifted. The variety of these effects of Ag A on microalgal fluorescence suggests that fluorophores derived from animals could play a crucial role in shaping the composition of marine host/symbiont systems.

scholarly journals Fluorimetric Properties of 3-Aminoflavone Biomolecule (3-AF). X-ray Crystal Structure of New Polymorph of 3-AF

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2927 ◽  
Author(s):  
Wojciech Pająk ◽  
Małgorzata Fabijańska ◽  
Jakub Wojciechowski ◽  
Wojciech M. Wolf ◽  
Anna Kilanowicz ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Limit Of Detection ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Polymorphic Form ◽  
X Ray Diffraction ◽  
Limit Of Quantification ◽  
Fluorescence Emission Spectra ◽  
X Ray ◽  
Optimal Values

The crystal structure of the new polymorphic form of 3-aminoflavone (3-AF) has been determined by single crystal X-ray diffraction. This report presents results of fluorimetric studies on 3-AF in methanol and aquatic solvents. Based on 3D fluorescence emission spectra, optimal values for excitation (λex) and emission/analytical (λem) wavelength, the analytical concentration range as well as the range of concentration quenching for the studied compound were established. Moreover, the limit of detection (LOD) and the limit of quantification (LOQ) were determined. The results were compared with those obtained using the standard UV-Vis absorption spectrophotometric method. The effect of acidity (pH) and the concentration of halide anions (chlorides, bromides, iodides and fluorides) on fluorescence quenching were analysed.

Visible and Near-Infrared Fluorescence of Crude Oils

1995 ◽  
Vol 49 (6) ◽  
pp. 754-764 ◽  
Author(s):  
Taggart D. Downare ◽  
Oliver C. Mullins
Keyword(s):  
Energy Transfer ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Quantum Yields ◽  
Crude Oils ◽  
Excitation Wavelength ◽  
Fluorescence Emission Spectra ◽  
Fluorescence Quantum Yields ◽  
Oil Type

Fluorescence emission spectra and absolute quantum yields have been measured for ten diverse crude oils at various concentrations over a broad range of excitation and emission wavelengths in the visible and the near-infrared. Energy transfer produces large red shifts and large widths in the fluorescence emission spectra for shorter wavelength excitation particularly for heavier crude oils. However, the effects of energy transfer are nearly absent for near-infrared excitation; all crude oils exhibit nearly the same emission spectra for long wavelength excitation. In addition, the fraction of emission resulting from collisional energy transfer relative to nascent emission is almost independent of oil type; it is governed by quantum yield characteristics. Absolute fluorescence quantum yields of ten crude oils (and three rhodamine dyes for validation) were measured with respect to scattering of latex microspheres in distilled water. Fluorescence quantum yields vary systematically with crude oil type as well as excitation wavelength; quantum yields are lower for high fluorophore concentrations (heavy crude oils) and for longer wavelength excitation. Stern-Volmer analyses of the quantum yields indicate that simple models apply and show the relative quenching rates for different excitation wavelengths.

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