Preparation method and application of nitrogen-doped carbon dots based on listeria monocytogenes source

Abstract

The invention belongs to the field of fluorescence sensors, and relates to a nitrogen-doped carbon dot, in particular to a preparation method and application of a nitrogen-doped carbon dot based on a listeria monocytogenes source. The method is based on nitrogen-doped carbon dots (NCDs-LM) derived from Listeria monocytogenes. The NCDs-LM is successfully synthesized by adopting a one-step solvothermal method. The fluorescence intensity of the NCDs-LM-based fluorescence sensor and the I <-> concentration have a good linear relationship, and the detection limit is 20 nmol / L. The sensor has been successfully applied to detection of I <-> in drinking water and milk samples. Meanwhile, the NCDs-LM-based sensor can be used for pH detection, and the detectable pH linear range is wide. In addition, fluorescent test paper based on NCDs-LM is designed and used for semi-quantitative detection of I <-> and pH through a naked eye colorimetric method. The research shows that the NCDs-LM-based fluorescence sensor has great application potential in the aspects of environmental monitoring and food analysis.

Description

technical field

[0001] The invention belongs to the field of fluorescence sensors, and relates to nitrogen-doped carbon dots, in particular to a preparation method and application of nitrogen-doped carbon dots based on Listeria monocytogenes. Background technique

[0002] Iodide (I - ), as a component of the human thyroid gland, plays an important physiological role in thyroid function. Iodine deficiency or excess can lead to various thyroid disorders. In general, human iodine intake is mainly through food and drinking water. Therefore, to achieve I in food - The simple and rapid determination of ions is of great significance to human physiology and health. So far, the commonly used analysis I - The methods include chromatography, mass spectrometry, capillary electrophoresis and electrochemical detection. However, these methods or equipment are expensive, or the sample preparation is complicated, which limits the wide application of these methods to a certain extent. ...

Examples

Embodiment 1

[0036] Example 1: Synthesis of NCDs-LMs

[0037] Listeria monocytogenes was shaken in 30 mL of TSB medium and cultured at 37°C overnight. collect 10 9 CFU / mL cells were centrifuged at 4000 × g for 3 min and washed 3 times with ultrapure water. Then, the resulting cell pellet was added with 10 g of urea and then resuspended in 20 mL of N,N-dimethylacetamide. The solution was uniformly mixed, transferred to a 150 mL Teflon-lined stainless steel autoclave, and reacted at 180 °C for 10 h. The obtained dark brown solution was centrifuged at 8000 × g for 10 min, and the supernatant was filtered through a 0.22 μm filter membrane. The product was then purified by silica gel column chromatography using methanol and ethyl acetate as eluents. The collected eluate was dried on a vacuum rotary evaporator, diluted with water, and stored at 4°C for later use.

[0038] Characterization of NCDs-LMs: The as-prepared NCDs-LMs were analyzed by transmission electron microscopy (TEM), X-ray pow...

Embodiment 2

[0042] Example 2: Synthesis of NCDs-LMs

[0043] Listeria monocytogenes was shaken in 30 mL of TSB medium and cultured at 37°C overnight. Collect 5×10 8 CFU / mL cells were centrifuged at 4000 × g for 3 min and washed 3 times with ultrapure water. Then, the resulting cell pellet was added with 7.5 g of urea and then resuspended in 30 mL of N,N-dimethylacetamide. The solution was evenly mixed, transferred to a 150 mL Teflon-lined stainless steel autoclave, and reacted at 180 °C for 10 h. The obtained dark brown solution was centrifuged at 8000 × g for 10 min, and the supernatant was filtered through a 0.22 μm filter membrane. The product was then purified by silica gel column chromatography using methanol and ethyl acetate as eluents. The collected eluate was dried on a vacuum rotary evaporator, diluted with water, and stored at 4°C for later use.

Embodiment 3

[0044] Example 3: Synthesis of NCDs-LMs

[0045] Listeria monocytogenes was shaken in 30 mL of TSB medium and cultured at 37°C overnight. collect 10 8 CFU / mL cells were centrifuged at 4000 × g for 3 min and washed 3 times with ultrapure water. Then, the resulting cell pellet was added with 5 g of urea and then resuspended in 30 mL of N,N-dimethylacetamide. The solution was uniformly mixed, transferred to a 150 mL Teflon-lined stainless steel autoclave, and reacted at 180 °C for 10 h. The obtained dark brown solution was centrifuged at 8000 × g for 10 min, and the supernatant was filtered through a 0.22 μm filter membrane. The product was then purified by silica gel column chromatography using methanol and ethyl acetate as eluents. The collected eluate was dried on a vacuum rotary evaporator, diluted with water, and stored at 4°C for later use.

technical field

[0001] The invention belongs to the field of fluorescence sensors, and relates to nitrogen-doped carbon dots, in particular to a preparation method and application of nitrogen-doped carbon dots based on Listeria monocytogenes. Background technique

[0002] Iodide (I - ), as a component of the human thyroid gland, plays an important physiological role in thyroid function. Iodine deficiency or excess can lead to various thyroid disorders. In general, human iodine intake is mainly through food and drinking water. Therefore, to achieve I in food - The simple and rapid determination of ions is of great significance to human physiology and health. So far, the commonly used analysis I - The methods include chromatography, mass spectrometry, capillary electrophoresis and electrochemical detection. However, these methods or equipment are expensive, or the sample preparation is complicated, which limits the wide application of these methods to a certain extent. ...

Examples

Embodiment 1

[0036] Example 1: Synthesis of NCDs-LMs

[0037] Listeria monocytogenes was shaken in 30 mL of TSB medium and cultured at 37°C overnight. collect 10 9 CFU / mL cells were centrifuged at 4000 × g for 3 min and washed 3 times with ultrapure water. Then, the resulting cell pellet was added with 10 g of urea and then resuspended in 20 mL of N,N-dimethylacetamide. The solution was uniformly mixed, transferred to a 150 mL Teflon-lined stainless steel autoclave, and reacted at 180 °C for 10 h. The obtained dark brown solution was centrifuged at 8000 × g for 10 min, and the supernatant was filtered through a 0.22 μm filter membrane. The product was then purified by silica gel column chromatography using methanol and ethyl acetate as eluents. The collected eluate was dried on a vacuum rotary evaporator, diluted with water, and stored at 4°C for later use.

[0038] Characterization of NCDs-LMs: The as-prepared NCDs-LMs were analyzed by transmission electron microscopy (TEM), X-ray pow...

Embodiment 2

[0042] Example 2: Synthesis of NCDs-LMs

[0043] Listeria monocytogenes was shaken in 30 mL of TSB medium and cultured at 37°C overnight. Collect 5×10 8 CFU / mL cells were centrifuged at 4000 × g for 3 min and washed 3 times with ultrapure water. Then, the resulting cell pellet was added with 7.5 g of urea and then resuspended in 30 mL of N,N-dimethylacetamide. The solution was evenly mixed, transferred to a 150 mL Teflon-lined stainless steel autoclave, and reacted at 180 °C for 10 h. The obtained dark brown solution was centrifuged at 8000 × g for 10 min, and the supernatant was filtered through a 0.22 μm filter membrane. The product was then purified by silica gel column chromatography using methanol and ethyl acetate as eluents. The collected eluate was dried on a vacuum rotary evaporator, diluted with water, and stored at 4°C for later use.

Embodiment 3

[0044] Example 3: Synthesis of NCDs-LMs

[0045] Listeria monocytogenes was shaken in 30 mL of TSB medium and cultured at 37°C overnight. collect 10 8 CFU / mL cells were centrifuged at 4000 × g for 3 min and washed 3 times with ultrapure water. Then, the resulting cell pellet was added with 5 g of urea and then resuspended in 30 mL of N,N-dimethylacetamide. The solution was uniformly mixed, transferred to a 150 mL Teflon-lined stainless steel autoclave, and reacted at 180 °C for 10 h. The obtained dark brown solution was centrifuged at 8000 × g for 10 min, and the supernatant was filtered through a 0.22 μm filter membrane. The product was then purified by silica gel column chromatography using methanol and ethyl acetate as eluents. The collected eluate was dried on a vacuum rotary evaporator, diluted with water, and stored at 4°C for later use.

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