RU2804088C1 - Method for making solution of carbon points from berry juices - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the production of a carbon solution from berry juices and can be used in the manufacture of luminescent materials. A method has been proposed for making a solution of carbon points from berry juices, which involves obtaining a reaction mixture, wherein the juice of lingonberries, or blueberries, or red currants, or bird cherry is used as berry juice, and a reaction mixture is obtained with the following ratio of components, in parts by weight: deionized water 100; 25% aqueous ammonia solution 35.8-36.2; berry juice 13.33±0.02, after which the resulting solution is placed in an autoclave and kept in a drying chamber at a temperature of 180±2°C for 1±0.5 hours and cooled to a temperature of 25±5°C, then the solution is subjected to dialysis purification for 12±1 hours.

EFFECT: making a solution of carbon dots from the juices of lingonberries, blueberries, red currants or bird cherry synthesized by a simple hydrothermal method, whereas the solution is non-toxic and has luminescence in the blue-green region of the spectrum.

1 cl, 6 dwg

Description

The invention relates to nanotechnology and can be used in the manufacture of luminescent materials in optoelectronic devices, catalysis and biomedicine.

Carbon dots are known to be a new class of carbon luminescent nanomaterials that have become an alternative to traditional semiconductor quantum dots and organic dyes due to their tunable luminescence, low toxicity and high biocompatibility. There is current interest in synthesizing carbon dots using green chemistry methods using natural, renewable precursors that offer low cost, high water solubility, and lower toxicity compared to synthetic carbon precursors. In this regard, carbon dots from natural precursors have great potential for developing applications in the fields of biomedicine, namely detection, bioimaging, theranostics, antibacterial drugs, etc. Based on this, it has been proposed to use berry juices growing in Yakutia as carbon precursors .

The synthesis of carbon dots from blueberries by ultrasonic treatment is known (see Ayşe Merve Aslandaş, Neslihan Balcı, Mustafa Arık, Halis Şakiroğlu, Yavuz Onganer, Kadem Meral, Liquid nitrogen-assisted synthesis of fluorescent carbon dots from Blueberry and their performance in Fe ³⁺ detection, Applied Surface Science, Volume 356, 2015, Pages 747-752, DOI: 10.1016/j.apsusc.2015.08.147). The disadvantage of this method is the labor-intensive stage of preparing the carbon precursor.

In addition, there is a known method for synthesizing carbon dots from orange juice by a hydrothermal method to create bioimaging agents (see Swagatika Sahu, Birendra Behera, Tapas K. Maitib Sasmita Mohapatra, Simple one-step synthesis of highly luminescent carbon dots from orange juice: application as excellent bio-imaging agents Chem. Commun., 2012, 48, 8835–8837. DOI: 10.1039/C2CC33796G ). The disadvantage of this known method is the use of toxic reagents at the purification stage.

The method for the synthesis of carbon dots from Lantana camara berries (Lantana vaulted) includes multi-step synthesis and purification processes (see Rajkumar Bandi, Ramakrishna Dadigala, Bhagavanth Reddy Gangapuram, Veerabhadram Guttena, Green synthesis of highly fluorescent nitrogen – Doped carbon dots from Lantana camara berries for effective detection of lead(II) and bioimaging, Journal of Photochemistry and Photobiology B: Biology, Volume 178, 2018, Pages 330-338, ISSN 1011-1344, https://doi.org/10.1016/j.jphotobiol.2017.11.010 ).

For the method of synthesizing carbon dots from Murray Koenigii berries (see M. Preethi, C. Viswanathan, N. Ponpandian, An environment-friendly route to explore the carbon quantum dots derived from curry berries (Murrayakoenigii L) as a fluorescent biosensor for detecting vitamin B12, Materials Letters, Volume 303, 2021, 130521, ISSN 0167-577X, https://doi.org/10.1016/j.matlet.2021.130521 ) carry out ultrasonic treatment of curry berries without the use of heat.

The disadvantage of the known solutions is the weak luminescence intensity of the resulting carbon dots.

The problem to be solved by the claimed invention is expressed in the creation of a method for producing a solution of carbon dots based on an original renewable (natural) precursor, characterized by relative technological simplicity, environmental friendliness, safety and cost-effectiveness of synthesis processes.

The technical effect obtained by solving the problem is expressed in the production of a solution of carbon points from the juices of lingonberries, blueberries, red currants or bird cherry, synthesized by a simple hydrothermal method, without the use of expensive equipment and reagents. The resulting solutions of carbon dots are non-toxic and have bright and stable luminescence.

To solve the problem, the method of obtaining a solution of carbon points from berry juices is characterized by the fact that it includes obtaining a reaction mixture; in this case, the juice of lingonberries or blueberries or red currants or bird cherry is used as berry juice, obtained using a blender and subsequent filtration, and a reaction mixture is obtained mixture with the following ratio of components, in parts by weight: deionized water – 100; 25% aqueous ammonia solution – 35.8-36.2; berry juice – 13.33±0.02, after which the resulting solution is placed in an autoclave, for example, a polytetrafluoroethylene autoclave and kept in a drying chamber at a temperature of 180±2°C for 1±0.5 hours and cooled to a temperature of 25± 5°C, then the solution is subjected to dialysis purification, for example, in a dialysis bag (MWCO 3.5 kDa), for 12±1 hours.

A comparative analysis of the features of the claimed method with the features of analogues indicates that the claimed method meets the “novelty” criterion.

The combination of features of the invention provides a solution to the stated technical problem, namely, obtaining a solution of carbon dots with bright and stable luminescence from renewable (natural) juice precursors of lingonberries, blueberries, red currants or bird cherry.

The essence of the claimed method for obtaining a solution of carbon dots lies in the interaction of juices of lingonberries, blueberries, red currants or bird cherry with water and an aqueous solution of ammonia at a temperature of 180±2°C in an autoclave for 1±0.5 hours.

The claimed technical solution is illustrated by a drawing, where figures 1 and 2 show the absorption spectra of aqueous solutions of carbon dots from berry juices (based on images on a Perkin Elmer spectrophotometer), characterizing ultraviolet absorption; Figure 3 shows emission spectra of carbon dots from berry juices (based on images on a Perkin Elmer LS 50B spectrometer), characterizing the luminescent properties of the resulting solutions.

The raw materials used are juices from lingonberries, blueberries, red currants or bird cherry, obtained by blending and filtering. An aqueous solution of ammonia, which has low toxicity and slight volatility, is used as a source of nitrogen and as a doping (alloying) agent.

The implementation of the invention is achieved as follows.

Components were loaded into a polytetrafluoroethylene autoclave based on 100 parts by weight. deionized water, namely, 6±0.1 ml of 25% aqueous ammonia solution (35.8-36.2 parts by weight) and 2±0.1 ml of berry juice were added to 15±0.1 ml of deionized water ( 13.33±0.02 parts by weight). Next, the solution with the autoclave was placed in a drying cabinet and kept for 1±0.5 hours at 180±2°C. After which the autoclave was cooled until the temperature reached 25±5°C.

During the synthesis, the resulting solution becomes brown. After cooling the solution, dialysis purification was performed to remove reaction byproducts. For this purpose, the solution in a dialysis bag with a pore size of 3.5 kDa was placed in deionized water and subjected to constant stirring. The duration of the cleaning process was 12±1 hours. Next, the purified solution was examined for the content of carbon points.

The absorption spectra and luminescence spectra of the obtained carbon dots were studied. In the absorption spectra, carbon dots from lingonberries, blueberries and red currants have one peak at 269 nm. This absorption band was attributed to the π→π* transition of aromatic bonds C=C (see Fig. 1). In bird cherry carbon dots there is a peak at 228 nm, which is due to π→π* transitions in the C=C bond, and a peak at 282 nm corresponds to the n→π* transition in the C=O bond (see Fig. 2).

The luminescence of the resulting carbon dots depends on the change in excitation wavelength (see Fig. 3). A shift in the maxima of the luminescence spectra of carbon dots from lingonberries was observed from 419 to 508 nm (see Fig. 3, a), from blueberries - from 407 to 511 nm (see Fig. 3, b), from red currants - from 396 to 503 nm (see Fig. 3, c), from bird cherry - from 422 to 510 nm (see Fig. 3, d).

Thus, the claimed technical solution makes it possible to obtain a solution of carbon dots from the juices of lingonberries, blueberries, red currants or bird cherry, synthesized by a simple hydrothermal method, while the solution is non-toxic and has luminescence in the blue-green region of the spectrum.

Claims (5)

A method of obtaining a solution of carbon points from berry juices, characterized in that it includes obtaining a reaction mixture, wherein the juice of lingonberries, or blueberries, or red currants, or bird cherry is used as berry juice, and a reaction mixture is obtained with the following ratio of components, in wt. .ch.: deionized water – 100; 25% aqueous ammonia solution – 35.8-36.2; berry juice – 13.33±0.02, after which the resulting solution is placed in an autoclave and kept in a drying chamber at a temperature of 180±2°C for 1±0.5 hours and cooled to a temperature of 25±5°C, then the solution is subjected to dialysis purification for 12±1 hours.