CC BY
0LUMINESCENT METHOD OF DETERMINING VANADIUM(V)
ION USING CARBON DOTS Farida Allambergenova, Zulayho Smanova, Nigora Qutlimurotova
National University of Uzbekistan, Department of Analytical Chemistry, Tashkent
city,
Republic of Uzbekistan, e-mail:allambergenovaf802@gmail.com tel:+998990634053
https://doi.org/10.5281/zenodo.10838249
With industrial development, non-biodegradable pollutants such as heavy metal ions are persistent in water bodies. Heavy metall pollution is very harmful to human health and the ecosystem. The task of determining heavy and toxic metals in various environmental objects remains one of the main problems of modern analytical chemistry and ecology [1]. Despite being heavy and toxic, vanadium, an essential element for animals and humans, is released into the environment by burning fossils and various industrial processes. Vanadium is a popular metal with high physiological, environmental and industrial importance [2]. Much attention has been paid to the biological role of vanadium, its toxicity to living organisms and the level of environmental contamination. Vanadium and its derivatives are toxic in high concentrations. Vanadium is a steel-gray, corrosion-resistant metal that exists in oxidation states from -1 to +5 [3]. Metal vanadium does not occur in nature, the most common valence states are +3, +4 and +5.
Figure 1. Structures of vanadium complexes.
Despite the fact that V(V) is the most toxic form of vanadium, little attention has been paid to the determination of V(V) species in soil and plants. Therefore, there is a need for a potential chemical agent that can detect and remove contaminants.
Today, the synthesis of small carbon dots with different functional groups from substances with large macromolecules remains a solution to several problems in the field of chemistry. Carbon dots are a luminescent nanomaterial with unique properties [4]. Carbon dots can be combined with N, S, P and B heteroatoms. They can be chemically modified to improve and exhibit some additional functional properties [5]. Due to their high fluorescent properties, easy preparation, and low cost, carbon dots (CDs) have great potential for fluorescence-based analytical applications.
Chitin is the second most abundant natural polysaccharide on earth after cellulose. The properties of chitosan are attributed to its multiple functional groups, including hydroxyl, amino acid, and acetamido groups, and to its polyelectrolyte and sugar-based polymeric properties. the presence of functional groups is the basis for the formation of intermolecular hydrogen bonds, causing strong chelating and complexing properties [6]. Chitosan has been widely used for the detection of many heavy metals. It has excellent chelating ability with Cu2+, As2+, Hg2+, Cd2+ and other heavy metals [7].
Highly sensitive and selective methods of fluorescent detection of studied metals in environmental objects have been developed [8]. The luminescence analysis method has advantages such as high sensitivity, selectivity, simplicity, speed and low error. Taking into account these
advantages, the main goal of our research is to determine the vanadium (V) ion with carbon dots by the luminescent method.
The use of chitosan-based carbon dots in the detection of metal ions has aroused a lot of interest among researchers andcarbon dots based on chitosan were synthesized by hydrothermal method. The luminescence intensity of the carbon dots showed a wavelength of 448 nm. When exposed to vanadium (V) ion, the synthesized carbon dots showed luminescence intensity of 406 nm.
As you can see from the pictures above, we can see a significant quenching of the luminescence when we expose the vanadium (V) ion to the carbon dots.
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2. Baharum H. et al. Molecular cloning, homology modeling and site-directed mutagenesis of vanadium-dependent bromoperoxidase (GcVBPO1) from Gracilariachangii (Rhodophyta) //Phytochemistry. - 2013. - T. 92. - S. 49-59.
3. Ghosh, SK; Saha, R.; Saha, B. Toxicity of inorganic vanadium compounds. Res. Chemistry. Intermed. 2015, 41, 4873-4897.
4. Hu L. et al. Multifunctional carbon dots with high quantum yield for imaging and gene delivery //Carbon. - 2014. vol. 67. p. 508-513.
5. Sagbas S., Sahiner N. Carbon dots: preparation, properties, and application //Nanocarbon and its Composites. - Woodhead Publishing, 2019. - S. 651-676.
6. El Kadib A. Green and functional aerogels by macromolecular and textural engineering of chitosan microspheres //The Chemical Record. - 2020. - T. 20. - no. 8. - S. 753-772.
7. Gedda G. et al. Green synthesis of carbon dots from prawn shells for highly selective and sensitive detection of copper ions //Sensors and Actuators B: Chemical.-2016.vol.224.p.396-403.
8. Smanova ZA et al. Immobilized Oxyazo Compounds as Analytical Reagents for the SorptionLuminescent Determination of Certain Metals //Turkish Online Journal of Qualitative Inquiry. -2021. - T. 12. - no. 9.
Figure 2. Chitosan-based carbon dots luminescence.
Figure 3. The situation when a vanadium (V) ion is added to a carbon dots in different environments.
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