Spectroscopic detection of Hg2+ in water samples using fluorescent carbon quantum dots as sensing probe

2021 ◽  
Vol 20 (1) ◽  
pp. 1-18
Author(s):  
Lavkesh Kumar Singh Tanwar ◽  
Srishti Sharma ◽  
Kallol K. Ghosh
Keyword(s):  
Quantum Dots ◽  
Water Samples ◽  
Carbon Quantum Dots ◽  
Spectroscopic Technique ◽  
Highly Sensitive ◽  
Ft Ir ◽  
Gibb’S Free Energy ◽  
Average Size ◽  
Ir Spectroscopic

Mercury (Hg2+) is remarked as toxic and hazardous element to global environment. Here, carbon quantum dots (CQDs) were synthesized by simple microwave assisted technique for Hg2+ detection in water samples via. fluorescence quenching and FT-IR spectroscopic approach. The morphology and chemical structure of synthesized CQDs was investigated by TEM, FT-IR, 13C-NMR, fluorescence and UV-vis spectroscopic technique. The resultant CQDs bears spherical morphology with an average size of 2–4 nm. The binding parameters, as Stern-Volmer quenching constant (Ksv) and binding constant for CQDs-Hg system was investigated by fluorescence method, whereas UV-vis techniques was employed for determination of thermodynamic parameters, as Gibb’s free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) at three different temperature (295, 298 and 305 K). Moreover, selectivity assay for Hg2+ detection has been studied in presence of other metal ions by FT-IR as well as fluorescence spectroscopy. Analytical assay was also successfully applied for Hg2+ in spiked water samples collected from different areas of Chhattisgarh, with 98–99 recovery %. The detection of Hg2+ has been demonstrated in the range of 0 to 5.0μM with 3.25 nM detection limit. The present method is found to be simple, highly sensitive and selective for sensing of Hg2+ in aquatic environmental samples using CQDs as sensing probe.

An ion-imprinted material embedded carbon quantum dots for selective fluorometric determination of lithium ion in water samples

2017 ◽  
Vol 184 (12) ◽  
pp. 4861-4868 ◽  
Author(s):  
Honghong Shao ◽  
Chunyan Li ◽  
Changchang Ma ◽  
Lin Sun ◽  
Rongru Chen ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Water Samples ◽  
Lithium Ion ◽  
Carbon Quantum Dots ◽  
Fluorometric Determination ◽  
Ion Imprinted

Determination of Deltamethrin in Water Samples Using Sulfur and Nitrogen Co-Doped Carbon Quantum Dots as a Chemiluminescence Probe

2021 ◽  
Vol 76 (10) ◽  
pp. 1217-1224
Author(s):  
Mitra Azimi ◽  
Jamshid L Manzoori ◽  
Mohammad Amjadi ◽  
Jafar Abolhasani
Keyword(s):  
Quantum Dots ◽  
Water Samples ◽  
Carbon Quantum Dots ◽  
Co Doped

An innovative highly sensitive electrochemical sensor based on modified electrode with carbon quantum dots and multiwall carbon nanotubes for determination of methadone hydrochloride in real samples

2020 ◽  
Vol 12 (43) ◽  
pp. 5210-5218
Author(s):  
Behzad Rezaei ◽  
Atena Tajaddodi ◽  
Ali. A. Ensafi
Keyword(s):  
Carbon Nanotubes ◽  
Quantum Dots ◽  
Graphite Electrode ◽  
Multiwall Carbon Nanotubes ◽  
Carbon Quantum Dots ◽  
Pencil Graphite Electrode ◽  
Real Samples ◽  
Highly Sensitive ◽  
Multiwall Carbon

To enhance the properties of a pencil graphite electrode (PGE), highly functionalized carbon quantum dots (CQDs) were synthesized and mixed with multiwall carbon nanotubes (MWCNTs) as novel modifiers for the preparation of working electrodes.

FT-IR Spectroscopic Investigation of 4,4'-Bipyridine Adsorption on Metal Oxide Surfaces

1996 ◽  
Vol 50 (3) ◽  
pp. 310-315 ◽  
Author(s):  
Stephen A. Bagshaw ◽  
Ralph P. Cooney
Keyword(s):  
Three Dimensional ◽  
Acid Sites ◽  
Spectroscopic Technique ◽  
Metal Oxide Surfaces ◽  
Silica Alumina ◽  
Ft Ir ◽  
Ir Spectroscopic ◽  
First Time ◽  
Surface Chemistries

4,4‘-Bipyridine (4bipy) adsorption on the surfaces of silica, alumina, and titania and the infrared (IR) spectra obtained therefrom are reported for the first time. This paper constitutes the second part of a multi-faceted investigation into the development of a vibrational spectroscopic technique for the determination of distances between surface acid sites of three-dimensional solid acids. The aforementioned oxides were chosen because their surface chemistries are generally well understood and because they constitute the pillars within pillar interlayered clay (PILC) catalysts. However, there is little information in the literature regarding the surface interactions of this novel and potentially useful spectroscopic probe. The pore structures of PILC materials have been investigated through 4bipy adsorption, the results of which will be reported in a later paper. The spectra obtained for adsorption on the parent oxides are discussed with reference to earlier 4bipy and 2,2’-bipyridine (2bipy) adsorption studies and indicate that the mode of adsorption is a unidentate, “end-on” arrangement in agreement with that observed for adsorption on MgO. This mode of adsorption results in a reduction in molecular symmetry of the adsorbed 4bipy from D2 h to C2γ. A previously unreported observation involving the high-temperature cleavage of the inter-ring bond of 4bipy adsorbed on γ-alumina and titania Lewis acid sites is described.

LUMINESCENT DETERMINATION OF SUGAR IN NATURAL HONEY

2020 ◽  
Vol 0 (4) ◽  
pp. 29-32
Author(s):  
B.M. GAREEV ◽  
◽  
A.M. ABDRAKHMANOV ◽  
G.L. SHARIPOV ◽  
◽  
...  
Keyword(s):  
Quantum Dots ◽  
Laboratory Test ◽  
Aqueous Solutions ◽  
Analytical Method ◽  
Sugar Content ◽  
Carbon Quantum Dots ◽  
Photoluminescence Intensity ◽  
Sucrose Content ◽  
Natural Honey

The photoluminescence of carbon quantum dots synthesized from natural honey and mixtures of honey and sugar has been studied. An increase in the sugar content leads to a decrease in the photoluminescence intensity without changing the shape of the luminescence spectrum of these quantum dots aqueous solutions, which is associated with a decrease in the yield of their synthesis in the sugar presence. The discovered effect can be used to detect sugar in honey. When examining five different market samples of flower honey using this method, two of them showed a significant decrease in the photoluminescence intensity. A laboratory test for compliance with GOST 19792-2017 Standard requirements established an excess of the sucrose content in these samples. Luminescent determination of sugar in honey does not require complicated equipment and can be used to develop a new analytical method for determining the sugar content in counterfeit natural honey.

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