Preparation method of nitrogen-doped graphene quantum dots (N-GQDs) and detection method of ascorbic acid

A technology of graphene quantum dots and ascorbic acid, applied in the field of fluorescence detection, achieves the effects of good dispersibility, uniform particle size, and solving difficulty in separation

Active Publication Date: 2017-10-10
HEBEI NORMAL UNIV FOR NATTIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, how to use the nanoscale reaction space and adopt a top-down method to confine and prepare high-perform

Method used

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  • Preparation method of nitrogen-doped graphene quantum dots (N-GQDs) and detection method of ascorbic acid
  • Preparation method of nitrogen-doped graphene quantum dots (N-GQDs) and detection method of ascorbic acid
  • Preparation method of nitrogen-doped graphene quantum dots (N-GQDs) and detection method of ascorbic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Example 1 Ordered mesoporous nitrogen-containing polymer / SiO 2 Preparation of composite materials

[0041] Mix ethyl orthosilicate, triblock copolymer P123 (Mw=5800), water and concentrated hydrochloric acid. This solution was transferred to an autoclave and reacted at 110°C for 24 hours. After the reaction, it was washed with a large amount of ultrapure water and ethanol and filtered, and the resulting product was dried at 60°C. Finally, the dried product was annealed at 550°C for 6 hours under air conditions to obtain ordered mesoporous silica SBA-15.

[0042] A mixture solution of pyrrole, trimethylbenzene, sulfuric acid and ethanol with a molar ratio of 1:5:3:0.4 was injected into SBA-15, heated in an oven at 80°C for 6 hours, and then reacted in an oven at 160°C for 8 hours. Then the obtained sample was heated at 800° C. in a nitrogen atmosphere for 4 hours to obtain a carbon / nitrogen / silica nanocomposite.

Embodiment 2

[0043] Example 2 Preparation of nitrogen-doped graphene quantum dots

[0044] Put the prepared carbon / nitrogen / silica nanocomposite in Example 1 into figure 1 In the glassware shown, put it in a reaction kettle containing concentrated nitric acid, and put the reaction kettle in an oven at 120-160°C for 1 to 3 hours. Finally, the glassware after the reaction was filtered in situ, and the yellow filtrate was collected as the N-GQDs solution.

[0045] Test the N-GQDs solution, see the results figure 2 , image 3 with Figure 4 , figure 2 This is a transmission electron micrograph of the N-GQDs prepared in Example 2 of the present invention; image 3 Are the atomic force microscope images and height images of the N-GQDs prepared in Example 2 of the present invention; Figure 4 This is the XPS spectrum of the N-GQDs prepared in Example 2 of the present invention.

[0046] by figure 2 It can be seen that the N-GQDs have uniform particle size and narrow distribution, with diameters rangi...

Embodiment 3A

[0049] Example 3 AA detection

[0050] Dilute 0.15~0.3mL of the N-GQDs solution prepared in Example 2 with 1.6~2mL of ultrapure water (≥18.2MΩ), then excite the N-GQDs with excitation wavelengths at 20nm intervals, with a slit of 5~10nm for fluorescence testing . The experimental results show that when the excitation wavelength is 340nm, its fluorescence emission peak intensity is the largest. Therefore, we choose 340nm as the excitation wavelength for the following fluorescence experiments.

[0051] The N-GQDs filtrate prepared in Example 2 was diluted with ultrapure water (≥18.2MΩ) to obtain a detection solution. Then add 50μM Fe 3+ Solution to form Fe 3+ -N-GQDs detection platform, and then add AA to measure the fluorescence intensity under different AA concentrations, and the recovered fluorescence intensity ratio F / F 0 It has a linear relationship with the amount of AA added, and draws a standard curve.

[0052] See results Figure 5 with Image 6 , Figure 5 This is Example ...

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Abstract

The invention provides a preparation method of nitrogen-doped graphene quantum dots (N-GQDs). The method comprises the following steps: A), mixing a carbon and nitrogen source, trimethylbenzene, sulfuric acid and ethanol and then injecting into ordered mesoporous silicon dioxide; heating for 2 to 8 hours at a temperature of 60 to 100 DEG C, carrying out reaction for 3 to 10 hours at a temperature of 120 to 180 DEG C, and then heating for 1 to 5 hours under a nitrogen atmosphere of 700 to 1000 DEG C to obtain a mesoporous carbon/nitrogen/silicon dioxide nano-compound, wherein the carbon and nitrogen source is pyrrole or quinoline; B) carrying out reaction on the carbon/nitrogen/silicon dioxide nano-compound in concentrated nitric acid steam to obtain the nitrogen-doped graphene quantum dots. The invention also provides a detection method of ascorbic acid. An experimental result proves that the obtained N-GQDs prepared by the method have uniform particle size, are narrower in distribution, have good dispersibility and have preferable water solubility. By using the N-GQDs as fluorescent probes, the N-GQDs have good selectivity on ascorbic acid and have good accuracy.

Description

Technical field [0001] The invention belongs to the technical field of fluorescence detection, and in particular relates to a method for preparing nitrogen-doped graphene quantum dots and a method for detecting ascorbic acid. Background technique [0002] Ascorbic acid (AA), also known as vitamin C, is abundantly present in food, animal body fluids and the human body. It is widely involved in the body's metabolic processes such as oxidation and reduction. It plays a vital role in the biochemical process and is an important part of life. It is a component of antioxidants, coenzyme factors and neurotransmitter-related enzymes. As we all know, the lack of AA will cause scurvy, but excessive intake can also cause urinary stones, diarrhea, stomach cramps and so on. Therefore, it is very important to accurately and simply detect the content of AA. [0003] The traditional methods for the detection of ascorbic acid mainly include optical method, chromatography, electrochemical method, f...

Claims

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Application Information

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IPC IPC(8): C09K11/65G01N21/64
CPCC09K11/65G01N21/6428
Inventor 许宏波周生海
Owner HEBEI NORMAL UNIV FOR NATTIES
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