CN110627046B - Nitrogen-doped graphene quantum dot and preparation method and application thereof - Google Patents

Nitrogen-doped graphene quantum dot and preparation method and application thereof Download PDF

Info

Publication number
CN110627046B
CN110627046B CN201910801991.6A CN201910801991A CN110627046B CN 110627046 B CN110627046 B CN 110627046B CN 201910801991 A CN201910801991 A CN 201910801991A CN 110627046 B CN110627046 B CN 110627046B
Authority
CN
China
Prior art keywords
nitrogen
graphene quantum
doped graphene
quantum dot
preparation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910801991.6A
Other languages
Chinese (zh)
Other versions
CN110627046A (en
Inventor
罗涛
唐卫中
陈洁
刘军杰
赵昌
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangxi Medical University Affiliated Tumour Hospital
Original Assignee
Guangxi Medical University Affiliated Tumour Hospital
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangxi Medical University Affiliated Tumour Hospital filed Critical Guangxi Medical University Affiliated Tumour Hospital
Priority to CN201910801991.6A priority Critical patent/CN110627046B/en
Publication of CN110627046A publication Critical patent/CN110627046A/en
Application granted granted Critical
Publication of CN110627046B publication Critical patent/CN110627046B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/15—Nano-sized carbon materials
    • C01B32/182—Graphene
    • C01B32/184—Preparation
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/65—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing carbon
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64—Fluorescence; Phosphorescence
    • G01N21/6486—Measuring fluorescence of biological material, e.g. DNA, RNA, cells
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/76—Chemiluminescence; Bioluminescence
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2204/00—Structure or properties of graphene
    • C01B2204/04—Specific amount of layers or specific thickness
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2204/00—Structure or properties of graphene
    • C01B2204/20—Graphene characterized by its properties

Abstract

The invention discloses a nitrogen-doped graphene quantum dot and a preparation method and application thereof, and belongs to the technical field of fluorescent nano materials. The preparation method of the nitrogen-doped graphene quantum dot comprises the following steps: and carrying out hydrothermal reaction on an aqueous solution containing aminopyrene under an alkaline condition to obtain the nitrogen-doped graphene quantum dot. According to the preparation method, the aminopyrene is simultaneously used as the carbon source and the nitrogen source for the first time, the graphene quantum dots with blue fluorescence are prepared in the alkaline solution through a one-step hydrothermal method, the preparation method is simple and easy to operate, the yield is high, and the fluorescence quantum yield of the product is high. The synthesized nitrogen-doped graphene quantum dots have 2-3 layers of graphene thickness, uniform size and single crystallinity; the fluorescence of the fluorescent probe can be specifically quenched by iron ions and cytochrome C, and is expected to be used for selectively detecting trace iron ions or cytochrome C; in addition, the nitrogen-doped graphene quantum dot synthesized by the method has an electrochemical luminescence property, and is expected to construct a high-sensitivity electrochemical sensing system.

Description

Nitrogen-doped graphene quantum dot and preparation method and application thereof
Technical Field
The invention relates to the technical field of fluorescent nano materials, in particular to a nitrogen-doped graphene quantum dot, a preparation method thereof and application thereof in detection of iron ions or cytochrome C.
Background
The Graphene Quantum Dots (GQDs) are zero-dimensional fluorescent carbon nano materials, the transverse dimension of the fluorescent carbon nano materials is less than 10nm, and the thickness of the fluorescent carbon nano materials is less than 10 layers. According to the difference of the thickness, the graphene quantum dots can be divided into single-layer, double-layer and multi-layer graphene quantum dots. GQDs have the advantages of adjustable band gap, easy surface modification, good biocompatibility, low cytotoxicity, stable photoluminescence and the like, so the GQDs have potential application prospects in the fields of photocatalysis, photoelectric detectors, solar cells, biological imaging, electrochemical sensors, fluorescence sensing and the like.
Compared with an organic small-molecule fluorescent probe, the graphene quantum dot fluorescent probe is simple in synthesis method and good in light stability; compared with semiconductor fluorescent quantum dots such as CdS, CdTe and the like, the graphene quantum dot probe is good in biocompatibility and free of toxicity.
Researchers have recently found that doping hetero atoms into GQDs to prepare hetero atom-doped GQDs is an effective means for regulating the structure and properties of GQDs. After the graphene structure in the GQDs is doped with heteroatoms, the electronic structure and the charge density of the whole conjugate plane can be obviously changed, so that the electron flow density and the forbidden bandwidth of the GQDs are influenced, and the physical and chemical properties of the GQDs, such as quantum yield, light stability, emission wavelength and the like, are further regulated and controlled. In addition, the doping of the heteroatom brings various functional groups and active sites for the GQDs, improves the selectivity and sensitivity of the GQDs based sensor, and greatly expands the application of the GQDs in fluorescence sensing. Common doping heteroatoms are N atoms, S atoms, B atoms, Cl atoms, F atoms, and the like. Although the N atoms (electron doping) are comparable in atomic size to the C atoms. However, the difference in electronegativity between C (2.55) and N (3.04) is large. Therefore, the doping of N element can effectively adjust the electronic characteristics of GQDs.
Common methods for preparing doped GQDs include top-down and bottom-up. The doped graphene sheets, carbon nanotubes, carbon fibers, etc. are cut into GQDs from top to bottom. Common methods include nanolithography, acid oxidation, ultrasonic assistance, microwave assistance, electrochemical methods, and the like. From bottom to top, small organic precursors are converted into GQDs by catalysis or heat treatment, and common preparation methods include hydrothermal or solvothermal methods, carbonization of organic precursors and the like. The carbon sources for preparing the doped GQDs are also various, and common carbon sources include Citric Acid (CA), Graphene Oxide (GO), glucose, fructose, trinitropyrene, carbon, coal and the like. Compared with the top-down method, the bottom-up synthesis method has high preparation yield. When a nitrogen-free compound is used as a carbon source to synthesize the nitrogen-doped graphene quantum dot, a dopant is required to be added at the same time, and when the nitrogen-containing compound is used to synthesize the nitrogen-doped graphene quantum dot, the nitrogen dopant is not required to be additionally introduced. Therefore, nitrogen-doped graphene quantum dots with excellent performance are expected to be prepared by a simple bottom-up method by taking a nitrogen-containing compound with a specific structure as a carbon source and a nitrogen source.
Disclosure of Invention
The invention aims to provide a novel raw material for preparing nitrogen-doped graphene quantum dots, the novel nitrogen-doped graphene quantum dots are prepared through a simple one-step hydrothermal reaction, and the fluorescence luminescence performance of the novel nitrogen-doped graphene quantum dots is excavated.
In order to achieve the purpose, the invention adopts the following technical scheme:
the preparation method of the nitrogen-doped graphene quantum dot comprises the step of carrying out hydrothermal reaction on an aqueous solution containing aminopyrene under an alkaline condition to prepare the nitrogen-doped graphene quantum dot.
The molecular formula of the aminopyrene is C16H11N, the structural formula is as follows:
Figure BDA0002182581070000021
according to the research of the invention, the aminopyrene can be used as a carbon source and a nitrogen source at the same time, and a new nitrogen-doped graphene quantum dot is prepared by a one-step hydrothermal method. The pyrene has a graphene mother-core structure, and the graphene quantum dots with excellent structural characteristics can be prepared through molecular fusion in a hydrothermal process.
The reaction product prepared by the preparation method is analyzed by an X-ray photoelectron spectrum chart, and the existence of nitrogen element is proved. This result demonstrates the efficient synthesis of nitrogen-doped graphene quantum dots.
Although the N atoms (electron doping) are comparable in atomic size to the C atoms. However, the difference in electronegativity between C (2.55) and N (3.04) is large. Therefore, the doping of N element can effectively adjust the electronic characteristics such as the energy level of GQDs. Research shows that the reaction product prepared by the technical scheme provided by the invention has bright blue fluorescence under the irradiation of a 365nm ultraviolet lamp; and the fluorescence will be quenched upon addition of iron ions or cytochrome C. After potassium persulfate is added into the reaction product solution prepared by the technical scheme provided by the invention, the cathode electrochemiluminescence performance is realized.
Due to poor water solubility of the aminopyrene, when the concentration of the aminopyrene is too high, the mixed solution for carrying out the hydrothermal reaction contains the aminopyrene which is not completely dissolved, and the mixed solution is a heterogeneous reaction medium, so that the concentration of the aminopyrene is not suitable to be too high. Preferably, the concentration of the aminopyrene in the hydrothermal reaction system is 0.1-5.0 mg/mL.
Preferably, the alkaline condition is adjusted by sodium hydroxide, and the concentration of the sodium hydroxide in the reaction system is 0.05-1.5 mol/L.
More preferably, the concentration of the aminopyrene in the reaction system is 0.5-2.0 mg/mL, and the concentration of the sodium hydroxide is 0.2-0.5 mol/L.
The hydrothermal reaction temperature is too low, and the reaction time is too long, so that the hydrothermal reaction efficiency is not improved. The heating temperature of the conventional hydrothermal kettle is 200 ℃ at most, the tolerance temperature of the conventional hydrothermal kettle is preferably 160-200 ℃, and the hydrothermal reaction temperature is comprehensively controlled. The time of the hydrothermal reaction is 4-20 hours.
In order to obtain nitrogen-doped graphene quantum dots with uniform size distribution and narrow fluorescence emission, the size of reaction products needs to be graded. The preparation method further comprises the following steps: after the hydrothermal reaction is finished, intercepting the nitrogen-doped graphene quantum dots with the molecular weight of 1000-3500 Da in the reaction product, namely the nitrogen-doped graphene quantum dots.
Preferably, the method of entrapment is dialysis or ultrafiltration. The dialysis purification method of the product comprises the following steps; and (3) after the reaction product is fully dialyzed by a dialysis bag with the molecular weight cutoff of 1000Da, fully dialyzing the solution in the dialysis bag by a dialysis bag with the molecular weight cutoff of 3500Da again, wherein the solution outside the dialysis bag is the nitrogen-doped graphene quantum dot solution. The nitrogen-doped graphene quantum dots subjected to size retention by two dialysis have relatively uniform particle size distribution.
The ultrafiltration purification method of the product comprises the following steps; placing the reaction product in an ultrafiltration tube with the molecular weight cutoff of 1000Da, freezing and centrifuging for 20min at 5000 r/min, and collecting the upper solution of the ultrafiltration tube. And placing the obtained solution into an ultrafiltration tube with the molecular weight cutoff of 3500Da again, freezing and centrifuging for 20min at 5000 r/min, collecting the part of the solution below the ultrafiltration tube, and carrying out ultrafiltration twice to obtain the nitrogen-doped graphene quantum dots with the sizes cutoff and relatively uniform particle size distribution.
The invention also provides the nitrogen-doped graphene quantum dot prepared by the preparation method. The nitrogen-doped graphene quantum dot has 2-3 layers of graphene with uniform thickness and size. Lattice lines can be obviously seen in a high-resolution transmission electron microscope, and the nitrogen-doped graphene quantum dot provided by the invention is proved to have single crystallinity. Due to the doping of nitrogen atoms, the prepared nitrogen-doped graphene quantum dot has bright blue fluorescence; the fluorescence of the graphene quantum dot can be specifically quenched by iron ions, and other metal ions (including sodium ions, potassium ions, calcium ions, magnesium ions, zinc ions, aluminum ions, nickel ions, copper ions, cobalt ions, chromium ions and lead ions) cannot quench the fluorescence of the graphene quantum dot, so that the nitrogen-doped graphene quantum dot has the selective recognition capability on the iron ions. In addition, the fluorescence of the nitrogen-doped graphene quantum dot can be quenched by cytochrome C, so that the selective recognition capability of the nitrogen-doped graphene quantum dot on the cytochrome C is shown, and a biosensor for detecting the cytochrome C is expected to be constructed. In addition, the nitrogen-doped graphene quantum dot synthesized by the method has an electrochemiluminescence property.
Therefore, the invention provides application of the nitrogen-doped graphene quantum dot in preparation of a kit for detecting iron ions or cytochrome C.
The invention also provides application of the nitrogen-doped graphene quantum dot in preparation of an electrochemical luminescence probe. The method comprises the steps that nitrogen-doped graphene quantum dots are used as an electrochemiluminescence probe and used for detecting a substance to be detected, specifically, the nitrogen-doped graphene quantum dots and potassium persulfate are added into a detection system and used as a co-reactant, when the substance to be detected in the detection system and the nitrogen-doped graphene quantum dots interact, the electrochemiluminescence intensity of the nitrogen-doped graphene quantum dots can change, a three-electrode system is adopted for determining the change of electrochemiluminescence signals, the electrochemiluminescence intensity is linearly related to the concentration of the substance to be detected, and then the concentration of the substance to be detected is determined. Preferably, the concentration of potassium persulfate in the detection system is 1-10 mmol/L.
The invention has the following beneficial effects:
(1) according to the preparation method, the aminopyrene is simultaneously used as the carbon source and the nitrogen source for the first time, the graphene quantum dots with blue fluorescence are prepared in the alkaline solution through a one-step hydrothermal method, the preparation method is simple and easy to operate, the yield is high, and the fluorescence quantum yield of the product is high.
(2) The nitrogen-doped graphene quantum dot synthesized by the preparation method has 2-3 layers of graphene with uniform thickness and size; lattice lines can be obviously seen in a high-resolution transmission electron microscope, and the nitrogen-doped graphene quantum dots synthesized by the method have single crystallinity.
(3) The fluorescence of the nitrogen-doped graphene quantum dots synthesized by the preparation method can be quenched by iron ions, and other metal ions (including sodium ions, potassium ions, calcium ions, magnesium ions, zinc ions, aluminum ions, nickel ions, copper ions, cobalt ions, chromium ions and lead ions) cannot quench the fluorescence of the nitrogen-doped graphene quantum dots, so that the nitrogen-doped graphene quantum dots have the selective recognition capability on the iron ions.
(4) The fluorescence of the nitrogen-doped graphene quantum dots synthesized by the preparation method can be quenched by cytochrome C, so that the selective recognition capability of the nitrogen-doped graphene quantum dots on the cytochrome C is shown, and the nitrogen-doped graphene quantum dots are expected to be used for constructing a biosensor for the cytochrome C.
(5) The nitrogen-doped graphene quantum dot synthesized by the method has the electrochemiluminescence property, and because the preparation method has the advantages of low price of raw materials and high yield of a one-step synthesis method, compared with the current commercialized electrochemiluminescence probe such as a tris (2, 2' -bipyridyl) ruthenium (II) dichloride complex (containing noble metal and having complex synthesis steps), the nitrogen-doped graphene quantum dot has the advantage of low cost; in addition, the nitrogen-doped graphene quantum dots are uniform in size and structure, and high in electrochemiluminescence stability.
Drawings
Fig. 1 is a graph of a result of a nitrogen-doped graphene quantum dot solution under irradiation of natural light and ultraviolet light, wherein a is irradiation of natural light, and B is excitation of 365nm ultraviolet light.
Fig. 2 is an X-ray photoelectron spectrum total spectrum (a) and a high-resolution N1s spectrum (B) of the nitrogen-doped graphene quantum dot.
Fig. 3 is an atomic force microscope photograph and a height distribution diagram of the nitrogen-doped graphene quantum dots, wherein a is the atomic force microscope photograph, and B is the height distribution diagram along a white line of the image a.
Fig. 4 is a transmission electron micrograph (a) and a high-resolution transmission electron micrograph (B) of the nitrogen-doped graphene quantum dot.
Fig. 5 is a photograph of the nitrogen-doped graphene quantum dot solution under 365nm ultraviolet irradiation after different metal ions are added. The metal ion concentration was 50. mu. mol/L.
Fig. 6 is a fluorescence spectrum (a) of the nitrogen-doped graphene quantum dot solution after iron ions with different concentrations are added and a linear relationship (B) between the fluorescence quenching rate and the iron ion concentration. The fluorescence quenching rate is F-F0/F0Is calculated to obtain wherein F0And F is the fluorescence intensity before and after iron ions are added into the nitrogen-doped graphene quantum dot solution.
Fig. 7 is a photograph of the nitrogen-doped graphene quantum dot solution after different concentrations of cytochrome C were added under 365nm ultraviolet irradiation.
Fig. 8 is a curve of the electrochemiluminescence signal of the nitrogen-doped graphene quantum dot along with the voltage. The electrochemical luminescence signal is measured by adopting a three-electrode system, a platinum electrode is taken as a working electrode and a counter electrode, and silver/silver chloride is taken as a reference electrode. Potassium persulfate (5mmol/L) is added into the nitrogen-doped graphene quantum dot solution to serve as a co-reactant.
Detailed Description
The invention is further illustrated by the following examples and figures.
Unless otherwise stated, the experimental methods mentioned in the examples are all conventional methods, and the reagents used are all purchased from conventional reagents companies.
Example 1
1. Hydrothermal synthesis of nitrogen-doped graphene quantum dots
Carrying out hydrothermal synthesis in a mixed aqueous solution of aminopyrene and sodium hydroxide for a certain time, dialyzing and purifying the obtained solution, and further carrying out freeze drying to obtain the graphene quantum dot solid. Wherein the concentration of the aminopyrene is 0.5mg/mL, the concentration of sodium hydroxide is 0.2mol/L, the hydrothermal reaction temperature is 200 ℃, and the hydrothermal reaction time is 10 h. And (3) after the reaction product is fully dialyzed by a dialysis bag with the molecular weight cutoff of 1000Da, fully dialyzing the solution in the dialysis bag by a dialysis bag with the molecular weight cutoff of 3500Da again, wherein the solution outside the dialysis bag is the nitrogen-doped graphene quantum dot solution.
2. Characterization and detection
The nitrogen-doped graphene quantum dots in the specific embodiment 1 are subjected to test characterization such as ultraviolet irradiation, atomic force microscopy, transmission electron microscopy, ion selectivity and the like, and the obtained test analysis results are shown in fig. 1-8.
The nitrogen-doped graphene quantum dot shown in fig. 1 is a light yellow solution (a) under natural light irradiation, and emits blue fluorescence (B) under 365nm ultraviolet light excitation.
The absolute quantum yield of the nitrogen-doped graphene quantum dots synthesized by the preparation method is higher than 20%. This result may be due to the introduction of doped N atoms.
Fig. 2 is a total spectrum (a) and a high-resolution N1s spectrum (B) of an X-ray photoelectron spectroscopy of the nitrogen-doped graphene quantum dot. The content of N atom is 3.2%, C-N-C and N- (C)3The presence of-demonstrates the doping of N atoms on the graphene parent core structure. The results effectively prove that the effective synthesis of the nitrogen-doped graphene quantum dots is calculated by a carbon source, and the yield of the nitrogen-doped graphene quantum dots synthesized by the preparation method is higher than 90%. The nitrogen-doped graphene quantum dots with uniform structures and sizes can be obtained after molecular fusion because the aminopyrene has a graphene parent-nucleus structure.
Fig. 3 is an atomic force microscope photograph and a height distribution diagram of the nitrogen-doped graphene quantum dots. As can be seen from fig. 3A, the thickness of the nitrogen-doped graphene quantum dot sheet is relatively uniform. As shown in fig. 3B, the thickness is about 1.5 nanometers. The nitrogen-doped graphene quantum dots have a graphene thickness of 2-3 layers in consideration of the influence of doping atoms.
Fig. 4 shows a transmission electron microscope photograph of the nitrogen-doped graphene quantum dot in fig. 4, and shows a high-resolution transmission electron microscope photograph in fig. B. It can be seen that the size of the nitrogen-doped graphene quantum dots is about 3-5 nm. The apparent carbon gridlines can be seen from the B plot. It was confirmed to have good crystallinity.
Fig. 5 is a photograph of the nitrogen-doped graphene quantum dot solution under 365nm ultraviolet irradiation after different metal ions are added. The metal ion concentration was 50. mu. mol/L. It can be seen that the fluorescence of the nitrogen-doped graphene quantum dot synthesized by the preparation method can be quenched by iron ions. Other metal ions (including sodium ions, potassium ions, calcium ions, magnesium ions, zinc ions, aluminum ions, nickel ions, copper ions, cobalt ions, chromium ions and lead ions) cannot quench the fluorescence of the metal ions, and the nitrogen-doped graphene quantum dots have the selective recognition capability on iron ions.
Fig. 6 is a fluorescence spectrum (a) of the nitrogen-doped graphene quantum dot solution after iron ions with different concentrations are added and a linear relationship (B) between the fluorescence quenching rate and the iron ion concentration. The fluorescence quenching rate is F-F0/F0Is calculated to obtain wherein F0And F is the fluorescence intensity before and after iron ions are added into the nitrogen-doped graphene quantum dot solution. The maximum emission wavelength of the nitrogen-doped graphene quantum dots is 415 nm. When the concentration of iron ions added into the nitrogen-doped graphene quantum dot solution is gradually increased, the fluorescence intensity of the nitrogen-doped graphene quantum dot solution is gradually reduced. The fluorescence quenching rate and the iron ion concentration show good linear relation when the iron ion concentration is 1.2-100.0 mu mol/L, and the detection limit is 0.3 mu mol/L.
Fig. 7 is a photograph of the nitrogen-doped graphene quantum dot solution after different concentrations of cytochrome C were added under 365nm ultraviolet irradiation. It can be seen that cytochrome C quenches its fluorescence. Although many existing fluorescent sensors based on graphene quantum dots are available, most of the existing fluorescent sensors are chemical sensors, and the detection objects are mostly metal cations. Few reports have been made on graphene quantum dots that are selective for biomolecules such as proteins. The nitrogen-doped graphene quantum dot prepared by the method is expected to be used for constructing a biosensor for detecting cytochrome C. After different concentrations of cytochrome C are added into the nitrogen-doped graphene quantum dot solution, the fluorescence quenching rate and the concentration of the cytochrome C are linearly related, the linear detection range of the cytochrome C is 50 mu g/mL-10.0mg/mL, and the detection limit is 13 mu mol/L.
Fig. 8 is a curve of the electrochemiluminescence signal of the nitrogen-doped graphene quantum dot along with the voltage. The electrochemical luminescence signal is measured by adopting a three-electrode system, a platinum electrode is taken as a working electrode and a counter electrode, and silver/silver chloride is taken as a reference electrode. Potassium persulfate (5mmol/L) is added into the nitrogen-doped graphene quantum dot solution to serve as a co-reactant. The electrochemical luminescence is a chemiluminescence phenomenon caused by electrochemical reaction, when a certain voltage is applied to a working electrode, nitrogen-doped graphene quantum dots generate free radicals after electrons are obtained from the electrode, persulfate generates disproportionation reactions after the electrons are obtained from the electrode, sulfate radicals are finally obtained, the nitrogen-doped graphene quantum dot free radicals and the sulfate radicals generate electron exchange reactions, the sulfate radicals are reduced, the nitrogen-doped graphene quantum dots are oxidized into a high-energy oxidation state, and molecules release energy to return to a low-energy state in a luminescence mode.
As can be seen from fig. 8, the nitrogen-doped graphene quantum dot prepared by the method of the present invention has high electrochemiluminescence performance. When the potential is lower than-0.4V, the nitrogen-doped graphene quantum dots start to emit light. The measurement was carried out 11 times in succession, and the standard deviation of the electrochemiluminescence intensity was 1.0%. The high electrochemiluminescence stability is attributed to the uniform size and surface energy level of the nitrogen-doped graphene quantum dots and the high crystallinity.
When a substance capable of interacting with the nitrogen-doped graphene quantum dot solution is added into the nitrogen-doped graphene quantum dot solution, the electrochemical luminescence intensity of the nitrogen-doped graphene quantum dot is changed, and a high-sensitivity electrochemical sensing system is expected to be constructed.
Compared with the current commercialized electrochemiluminescence probe such as tris (2, 2' -bipyridine) ruthenium (II) dichloride complex, the nitrogen-doped graphene quantum dot has the advantages of low price, good biocompatibility and high luminescence stability.
Example 2
1. Hydrothermal synthesis of nitrogen-doped graphene quantum dots
Carrying out hydrothermal synthesis in a mixed aqueous solution of aminopyrene and sodium hydroxide for a certain time, dialyzing and purifying the obtained solution, and further carrying out freeze drying to obtain the graphene quantum dot solid. Wherein the concentration of the aminopyrene is 2.0mg/mL, the concentration of sodium hydroxide is 0.5mol/L, the hydrothermal reaction temperature is 180 ℃, and the hydrothermal reaction time is 6 h. And (3) after the reaction product is fully dialyzed by a dialysis bag with the molecular weight cutoff of 1000Da, fully dialyzing the solution in the dialysis bag by a dialysis bag with the molecular weight cutoff of 3500Da again, wherein the solution outside the dialysis bag is the nitrogen-doped graphene quantum dot solution.
2. Characterization and detection
The nitrogen-doped graphene quantum dots prepared in example 2 also have 2-3 layers of structures and blue fluorescence, iron ions can quench the fluorescence of the nitrogen-doped graphene quantum dots, and other metal ions such as sodium ions, potassium ions, calcium ions, magnesium ions, zinc ions, aluminum ions, nickel ions, copper ions, cobalt ions, chromium ions, and lead ions have no quenching effect on the fluorescence of the nitrogen-doped graphene quantum dots. Cytochrome C can quench the fluorescence of nitrogen-doped graphene quantum dots. The nitrogen-doped graphene quantum dots have electrochemical luminescence properties.
The above embodiments are merely preferred embodiments of the present invention, which are not intended to be exhaustive. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative efforts belong to the protection scope of the present invention.

Claims (8)

1. The preparation method of the nitrogen-doped graphene quantum dot is characterized by comprising the following steps of carrying out hydrothermal reaction on an aqueous solution containing aminopyrene shown in a structural formula (I) under an alkaline condition to prepare the nitrogen-doped graphene quantum dot; the temperature of the hydrothermal reaction is 160-200 ℃;
Figure FDA0002789491010000011
2. the preparation method of the nitrogen-doped graphene quantum dot according to claim 1, wherein the concentration of the aminopyrene in a hydrothermal reaction system is 0.1-5.0 mg/mL.
3. The method for preparing the nitrogen-doped graphene quantum dot according to claim 1, wherein the alkaline condition is adjusted by sodium hydroxide, and the concentration of the sodium hydroxide in the reaction system is 0.05-1.5 mol/L.
4. The method for preparing the nitrogen-doped graphene quantum dot according to claim 1, wherein the hydrothermal reaction time is 4-20 hours.
5. The method for preparing nitrogen-doped graphene quantum dots according to claim 1, further comprising: and after the hydrothermal reaction is finished, intercepting the nitrogen-doped graphene quantum dots with the molecular weight of 1000-3500 Da in the reaction product to obtain the nitrogen-doped graphene quantum dots.
6. A nitrogen-doped graphene quantum dot prepared by the preparation method of any one of claims 1 to 5.
7. The application of the nitrogen-doped graphene quantum dot of claim 6 in preparing a kit for detecting iron ions or cytochrome C.
8. The use of the nitrogen-doped graphene quantum dot of claim 6 in the preparation of an electrochemiluminescence probe.
CN201910801991.6A 2019-08-28 2019-08-28 Nitrogen-doped graphene quantum dot and preparation method and application thereof Active CN110627046B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910801991.6A CN110627046B (en) 2019-08-28 2019-08-28 Nitrogen-doped graphene quantum dot and preparation method and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910801991.6A CN110627046B (en) 2019-08-28 2019-08-28 Nitrogen-doped graphene quantum dot and preparation method and application thereof

Publications (2)

Publication Number Publication Date
CN110627046A CN110627046A (en) 2019-12-31
CN110627046B true CN110627046B (en) 2021-04-09

Family

ID=68969359

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910801991.6A Active CN110627046B (en) 2019-08-28 2019-08-28 Nitrogen-doped graphene quantum dot and preparation method and application thereof

Country Status (1)

Country Link
CN (1) CN110627046B (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111678905A (en) * 2020-06-15 2020-09-18 青岛峰峦新材料科技有限责任公司 Cu2O-Ag-nitrogen doped graphene nanocomposite surface enhanced Raman substrate and preparation method thereof
CN111678906A (en) * 2020-06-15 2020-09-18 青岛峰峦新材料科技有限责任公司 MoS2Surface-enhanced Raman substrate made of Ag-N-doped graphene nanocomposite and preparation method thereof
CN112599788B (en) * 2021-01-11 2023-06-23 西北师范大学 N-GQDs/AgPt hollow dendritic structure nanocomposite and preparation and application thereof
CN113145151B (en) * 2021-01-30 2022-11-15 上海应用技术大学 Modified N-GQDs @ CdS nano-catalyst and preparation and application thereof
CN113184834B (en) * 2021-04-28 2022-08-09 浙江理工大学 Nitrogen-doped graphene quantum dot, preparation thereof and application thereof in detecting hydrogen peroxide
CN113289654B (en) * 2021-05-06 2022-09-06 浙江理工大学 Nitrogen-doped graphene quantum dot-iron ion composite nanoenzyme and preparation and application thereof

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101325530B1 (en) * 2011-10-06 2013-11-07 주식회사 케이씨씨 Functionalized methods of high quality graphene using conjugated system
CN105800595A (en) * 2016-02-22 2016-07-27 桂林理工大学 Nitrogen-doped graphene quantum dot and preparation method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101462901B1 (en) * 2012-11-29 2014-11-20 성균관대학교산학협력단 Light emtting device using graphene quantum dot and organic light emitting device including the same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101325530B1 (en) * 2011-10-06 2013-11-07 주식회사 케이씨씨 Functionalized methods of high quality graphene using conjugated system
CN105800595A (en) * 2016-02-22 2016-07-27 桂林理工大学 Nitrogen-doped graphene quantum dot and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
One-step synthesis of self-doped carbon dots with highly photoluminescence as multifunctional biosensors for detection of iron ions and PH;Wang,RX;Wang,XF;Sun,YM;《Sensors and Actuators B》;20171231;第241卷;第73-79页 *

Also Published As

Publication number Publication date
CN110627046A (en) 2019-12-31

Similar Documents

Publication Publication Date Title
CN110627046B (en) Nitrogen-doped graphene quantum dot and preparation method and application thereof
Ge et al. One-step synthesis of boron-doped graphene quantum dots for fluorescent sensors and biosensor
Xu et al. Fabrication of 2D/2D Z-scheme highly crystalline carbon nitride/δ-Bi2O3 heterojunction photocatalyst with enhanced photocatalytic degradation of tetracycline
Yin et al. Atmospheric pressure synthesis of nitrogen doped graphene quantum dots for fabrication of BiOBr nanohybrids with enhanced visible-light photoactivity and photostability
Chen et al. All-inorganic perovskite quantum dot/TiO 2 inverse opal electrode platform: Stable and efficient photoelectrochemical sensing of dopamine under visible irradiation
Sun et al. Recent advances in graphene quantum dots for sensing
Li et al. Facile electrodeposition of environment-friendly Cu2O/ZnO heterojunction for robust photoelectrochemical biosensing
Magesh et al. Recent advances on synthesis and potential applications of carbon quantum dots
Qi et al. An efficient edge-functionalization method to tune the photoluminescence of graphene quantum dots
Qin et al. One-pot synthesis of dual carbon dots using only an N and S co-existed dopant for fluorescence detection of Ag+
Masteri-Farahani et al. Boric acid modified S and N co-doped graphene quantum dots as simple and inexpensive turn-on fluorescent nanosensor for quantification of glucose
Chen et al. Design of 2D/2D CoAl LDH/g-C3N4 heterojunction-driven signal amplification: Fabrication and assay for photoelectrochemical aptasensor of ofloxacin
Chen et al. Recent advances of electrochemiluminescent system in bioassay
Zhou et al. Strong electrochemiluminescent interactions between carbon nitride nanosheet–reduced graphene oxide nanohybrids and folic acid, and ultrasensitive sensing for folic acid
Zou et al. CuO–ZnO heterojunction derived from Cu2+-doped ZIF-8: A new photoelectric material for ultrasensitive PEC immunoassay of CA125 with near-zero background noise
Yang et al. Sulfur-doped carbon quantum dots and derived 3D carbon nanoflowers are effective visible to near infrared fluorescent probes for hydrogen peroxide
Ibrahim et al. Selective and sensitive visible-light-prompt photoelectrochemical sensor of Cu2+ based on CdS nanorods modified with Au and graphene quantum dots
Liu et al. A novel fluorescence assay based on self-doping biomass carbon dots for rapid detection of dimethoate
CN110938430A (en) Silicon and nitrogen co-doped carbon quantum dot and preparation method and application thereof
Kong et al. The sensitive turn-on fluorescence detection of ascorbic acid based on iron (III)-modulated nitrogen-doped graphene quantum dots
Deng et al. Signal amplification by adsorption-induced catalytic reduction of dissolved oxygen on nitrogen-doped carbon nanotubes for electrochemiluminescent immunoassay
Wang et al. Molecularly imprinted photoelectrochemical sensor for aflatoxin B1 detection based on organic/inorganic hybrid nanorod arrays
Zhu et al. Double ion-exchange reaction-based photoelectrochemical immunoassay for sensitive detection of prostate-specific antigen
Ghosh et al. Current scenario and recent advancement of doped carbon dots: a short review scientocracy update (2013–2022)
Chen et al. Photocatalytic fuel cell self-powered sensor for Cu2+ detection in water and soil: Signal amplification of biomass induced carbon-rich carbon nitride photoanode

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant