Preparation method of fluorescent probe for detecting polycyclic aromatic hydrocarbon in industrial wastewater

Abstract

The invention relates to the technical field of environmental pollutant detection, and discloses a preparation method of a fluorescent probe for detecting polycyclic aromatic hydrocarbon in industrial wastewater, and the preparation method comprises the following steps: dissolving a carbon source substance and a nitrogen source substance in deionized water to form a mixed solution; transferring the mixed solution into a hydrothermal reaction kettle for heat treatment to obtain a nitrogen-doped carbon quantum dot initial product; and dialyzing and purifying the head product to obtain the purified nitrogen-doped carbon quantum dots. A specific recognition cavity which is complementary with a polycyclic aromatic hydrocarbon molecular space structure, size and functional group is constructed on the surface of the carbon quantum dot through a molecular imprinting technology, and the imprinting layer endows the probe with excellent molecular selectivity; benzene series, heavy metal ions and anionic surfactant interfering substances coexisting in the industrial wastewater are difficult to enter an imprinting cavity due to size mismatching or acting force difference, so that non-specific adsorption is remarkably reduced, and the detection accuracy and the anti-interference capability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental pollutant detection, in particular to a preparation method of a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater. BACKGROUND

[0002] As a typical persistent organic pollutant in industrial wastewater, polycyclic aromatic hydrocarbons have attracted widespread attention due to their strong carcinogenicity, teratogenicity and environmental accumulation. It is of great significance to establish a rapid, sensitive and specific detection method for environmental protection and human health. At present, the detection of polycyclic aromatic hydrocarbons mainly relies on instrumental analysis methods such as gas chromatography-mass spectrometry and high performance liquid chromatography. Although these methods can achieve accurate quantification, they have problems such as expensive instruments, tedious sample pretreatment, long detection period and the need for professional technical personnel, which makes it difficult to meet the actual needs of on-site rapid screening and online monitoring of industrial wastewater. Fluorescence analysis has become a research hotspot due to its advantages of simple operation, rapid response and high sensitivity. However, traditional organic fluorescent dyes generally have poor light stability, are prone to photobleaching, and have insufficient chemical stability. In complex wastewater matrix, the fluorescence signal is severely attenuated, and the reusability is poor.

[0003] In recent years, carbon quantum dots have gradually become a substitute for traditional dyes as a new type of fluorescent nanomaterial. They have excellent optical properties, good photochemical stability, low toxicity and water dispersibility. However, unmodified carbon quantum dots lack specific recognition ability for polycyclic aromatic hydrocarbon molecules and are easily interfered by structural analogues in complex systems, resulting in insufficient detection selectivity. Molecular imprinting technology can impart high selective recognition function to materials by constructing specific recognition sites complementary to the spatial structure of target molecules in polymers. However, traditional molecularly imprinted polymers have inherent defects such as incomplete elution of template molecules, embedding of recognition sites too deep, slow mass transfer rate, and long adsorption-desorption equilibrium time. In addition, the rigid polymer skeleton is prone to swelling or shrinking in complex aqueous environments, affecting the stability of the recognition cavity structure. Although attempts have been made to combine carbon quantum dots with molecular imprinting technology in existing technologies, they are mostly achieved through simple physical coating or post-grafting methods, which have problems such as uneven thickness of the imprinted layer, unstable combination of the core-shell structure, low utilization rate of active sites on the surface of carbon quantum dots, and unsatisfactory removal efficiency of template molecules. This leads to unstable fluorescence performance, insufficient recognition specificity, and limited anti-interference ability of the prepared probe, making it difficult to effectively cope with the influence of coexisting benzene series, heavy metal ions and surfactants in industrial wastewater.

[0004] Therefore, there is an urgent need to develop a preparation method that can achieve uniform and controllable growth of a molecularly imprinted layer on the surface of carbon quantum dots, construct a fluorescent probe with stable structure, specific recognition and rapid response, to meet the practical application needs of on-site rapid detection of polycyclic aromatic hydrocarbons in industrial wastewater. SUMMARY

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater, thus solving the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater, comprising the following steps:

[0007] The carbon source and nitrogen source are dissolved in deionized water to form a mixed solution;

[0008] The mixed solution was transferred to a hydrothermal reactor for heat treatment to obtain nitrogen-doped carbon quantum dot primary product; the primary product was then purified by dialysis to obtain purified nitrogen-doped carbon quantum dots.

[0009] The purified nitrogen-doped carbon quantum dots were surface-allylated using an allyl-containing silane coupling agent to obtain allylated carbon quantum dots; the allylated carbon quantum dots were then dissolved in a porogen to form a polymerization system along with polycyclic aromatic hydrocarbon template molecules, functional monomers, crosslinking agents, and initiators.

[0010] The polymerization system was subjected to a heating polymerization reaction under a protective atmosphere to form a molecularly imprinted polymer layer on the surface of carbon quantum dots, thereby obtaining a core-shell structured composite.

[0011] Template molecules in the core-shell complex were removed by Soxhlet extraction to obtain a fluorescent probe with molecularly imprinted polymer-coated carbon quantum dots.

[0012] Preferably, the carbon source is selected from at least one of citric acid, glucose, and ascorbic acid, and the nitrogen source is selected from at least one of ethylenediamine, triethylamine, and urea. The molar ratio of the carbon source to the nitrogen source is 1:1 to 1:5, and the concentration of the carbon source in the mixed solution is 0.1 to 0.5 mol / L.

[0013] Preferably, the heat treatment temperature in the hydrothermal reactor is set to 180-220℃, the heat treatment time is controlled to 6-12h, the heating rate is controlled to 5-10℃ / min, and the reactor is naturally cooled to 25℃ after the reaction is completed.

[0014] Preferably, the dialysis purification uses a dialysis bag with a molecular weight cutoff of 500-1000 Da, the dialysis time is 24-48 hours, the dialysis medium is deionized water, and the water is changed no less than 5 times during the dialysis process.

[0015] Preferably, the silane coupling agent used for the surface allyl modification is 3-allyloxypropyltrimethoxysilane or allyltriethoxysilane, and the mass ratio of the silane coupling agent to the purified nitrogen-doped carbon quantum dots is 1:5-1:10. The modification reaction is carried out at 60-80℃ for 4-8 hours.

[0016] Preferably, the polycyclic aromatic hydrocarbon template molecule is pyrene, phenanthrene or anthracene, the functional monomer is methacrylic acid or acrylamide, the crosslinking agent is ethylene glycol dimethacrylate, the initiator is azobisisobutyronitrile, and the porogen is a mixed solvent of acetonitrile and toluene in a volume ratio of 3:1 to 5:1.

[0017] Preferably, the mass ratio of the allylated carbon quantum dots to the template molecules is 1:2-1:5, the molar ratio of the functional monomer to the template molecules is 4:1-8:1, the molar ratio of the crosslinking agent to the functional monomer is 5:1-10:1, and the amount of initiator is 1%-3% of the total mass of the functional monomer and the crosslinking agent.

[0018] Preferably, the polymerization reaction is carried out under nitrogen or argon protection, the reaction temperature is set to 60-70℃, the reaction time is 12-24h, and after the reaction is completed, the product is washed 3-5 times with anhydrous ethanol and dried under vacuum at 50℃ for 12h.

[0019] Preferably, the solvent used for Soxhlet extraction is a mixture of methanol and acetic acid in a volume ratio of 9:1-8:2, the extraction temperature is 80-85℃, the extraction time is 24-36h, the extracted product is washed with deionized water until neutral, and then vacuum dried at 40℃ for 24h. The final fluorescent probe has a particle size of 50-200nm, a quantum yield ≥35%, and a detection limit for polycyclic aromatic hydrocarbons ≤5μg / L.

[0020] A fluorescent probe for detecting polycyclic aromatic hydrocarbons (PAHs) in industrial wastewater is disclosed. The probe has a core-shell structure consisting of a carbon quantum dot core and a molecularly imprinted polymer shell. The carbon quantum dot core has a diameter of 5-10 nm, and the molecularly imprinted polymer shell has a thickness of 20-95 nm. The surface has imprinted cavities that are complementary to the size, shape, and functional groups of PAH molecules. Under 365 nm ultraviolet light excitation, it emits blue fluorescence with a wavelength of 420-460 nm. Upon binding with PAHs, it produces a fluorescence quenching response with a quenching efficiency ≥85%. The fluorescence intensity fluctuates ≤±5% within the pH range of 5-9. The probe exhibits an anti-interference ratio ≥90% against benzene compounds, heavy metal ions, and anionic surfactants.

[0021] This invention provides a method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons (PAHs) in industrial wastewater. It has the following beneficial effects:

[0022] 1. This invention constructs a specific recognition cavity on the surface of carbon quantum dots using molecular imprinting technology. This cavity is complementary to the spatial structure, size, and functional groups of polycyclic aromatic hydrocarbon molecules. This imprinted layer endows the probe with excellent molecular selectivity. Due to size mismatch or differences in interaction forces, benzene series compounds, heavy metal ions, and anionic surfactants coexisting in industrial wastewater are difficult to enter the imprinted cavity, which significantly reduces non-specific adsorption and improves detection accuracy and anti-interference ability.

[0023] 2. Compared with traditional organic fluorescent dyes, the nitrogen-doped carbon quantum dots of this invention have superior photochemical stability and anti-photobleaching properties as fluorescent cores. The molecularly imprinted polymer layer on the surface forms a physical protective barrier, which enhances the structural stability and fluorescence performance of the probe in complex wastewater systems. It can maintain detection activity even after multiple cycles, reducing the cost of a single detection.

[0024] 3. The probe of this invention is based on the principle of fluorescence quenching. When polycyclic aromatic hydrocarbon molecules specifically bind to the imprinted cavity, it triggers significant fluorescence quenching of carbon quantum dots, producing an easily identifiable signal change. This response mechanism can achieve homogeneous rapid detection without complex sample pretreatment, greatly shortening the detection cycle and meeting the application requirements of rapid on-site screening and online monitoring of industrial wastewater. Attached Figure Description

[0025] Figure 1 This is the overall flowchart of the present invention;

[0026] Figure 2 This is a flowchart illustrating the synthesis and post-processing of the molecularly imprinted fluorescent probe of the present invention. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see the appendix Figure 1 - Appendix Figure 2 This invention provides a method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater.

[0029] Example 1

[0030] Citric acid and ethylenediamine were mixed in a molar ratio of 1:3 and dissolved in deionized water to prepare a mixed solution with a carbon source concentration of 0.3 mol / L. The solution was transferred to a hydrothermal reactor and reacted at 8 °C / min to 200 °C for 8 h. After natural cooling to 25 °C, nitrogen-doped carbon quantum dots were obtained as the initial product. The initial product was placed in a dialysis bag with a molecular weight cutoff of 800 Da and dialyzed against deionized water for 36 h, with the water changed 6 times to obtain purified carbon quantum dots. 1 g of purified carbon quantum dots was dispersed in ethanol, and 0.15 g of 3-allyloxypropyltrimethoxysilane was added. The mixture was stirred at 70 °C for 6 h to obtain allylated carbon quantum dots. 0.2 g of allylated carbon quantum dots, 0.6 g of pyrene template molecules, 2.4 mmol of methacrylic acid functional monomers, 15 mmol of ethylene glycol dimethacrylate crosslinking agent, and 0.05 g of azobisisobutyronitrile initiator were dissolved in a mixed porogen of acetonitrile / toluene (volume ratio 4:1) to form a polymerization system. Polymerization was carried out at 65 °C for 18 h under nitrogen protection. The product was washed four times with anhydrous ethanol, dried under vacuum at 50 °C for 12 h, then extracted with a Soxhlet extractant of methanol / acetic acid (volume ratio 8:2) for 30 h, washed with deionized water until neutral, and dried under vacuum at 40 °C for 24 h to obtain the pyrene molecularly imprinted fluorescent probe.

[0031] Example 2

[0032] Glucose and triethylamine were mixed in a molar ratio of 1:2 and dissolved in deionized water to prepare a mixed solution with a carbon source concentration of 0.2 mol / L. This solution was transferred to a hydrothermal reactor and reacted at 190°C for 10 h with the temperature increased at 6°C / min. After dialysis purification, 1 g of carbon quantum dots was added to 0.2 g of allyltriethoxysilane and reacted at 75°C for 5 h. 0.25 g of allylated carbon quantum dots, 0.5 g of phenanthrene template molecules, 2.8 mmol of acrylamide functional monomer, 18 mmol of ethylene glycol dimethacrylate crosslinking agent, and 0.06 g of initiator were dissolved in an acetonitrile / toluene porogen at a volume ratio of 3:1 and polymerized at 68°C for 20 h under argon protection. Subsequent processing was the same as in Example 1 to obtain a polymer-imprinted fluorescent probe.

[0033] Example 3

[0034] Ascorbic acid and urea were mixed at a molar ratio of 1:4 and dissolved in deionized water to prepare a mixed solution with a carbon source concentration of 0.4 mol / L. This solution was transferred to a hydrothermal reactor and reacted at 210°C for 7 hours, increasing the temperature by 9°C / min. After dialysis purification, 1 g of carbon quantum dots was added to 0.12 g of 3-allyloxypropyltrimethoxysilane and reacted at 65°C for 7 hours. 0.15 g of allylated carbon quantum dots, 0.75 g of dual-template molecules, 3.2 mmol of methacrylic acid functional monomer, 20 mmol of crosslinking agent, and 0.07 g of initiator were dissolved in an acetonitrile / toluene porogen at a volume ratio of 5:1 and polymerized at 62°C for 16 hours under nitrogen protection. Subsequent processing was the same as in Example 1 to obtain anthracene molecularly imprinted fluorescent probes.

[0035] Example 4

[0036] Citric acid and ethylenediamine were mixed in a molar ratio of 1:1 and dissolved in deionized water to prepare a mixed solution with a carbon source concentration of 0.1 mol / L. The hydrothermal reaction conditions were the same as in Example 1. 0.8 g of purified carbon quantum dots were added to 0.1 g of silane coupling agent and reacted at 60 °C for 8 h. 0.2 g of allylated carbon quantum dots, 0.4 g of pyrene template molecules, 2.0 mmol of functional monomer, 12 mmol of crosslinking agent, and 0.04 g of initiator were dissolved in an acetonitrile / toluene porogen at a volume ratio of 3:1 and polymerized at 60 °C for 24 h under nitrogen protection. Subsequent processing was the same as in Example 1 to obtain a pyrene molecularly imprinted fluorescent probe.

[0037] Example 5

[0038] Glucose and triethylamine were mixed in a molar ratio of 1:5 and dissolved in deionized water to prepare a mixed solution with a carbon source concentration of 0.5 mol / L. The hydrothermal reaction conditions were the same as in Example 2. 1.2 g of purified carbon quantum dots were added to 0.24 g of silane coupling agent and reacted at 80 °C for 4 h. 0.3 g of allylated carbon quantum dots, 0.9 g of phenanthrene template molecules, 4.0 mmol of functional monomers, 25 mmol of crosslinking agent, and 0.08 g of initiator were dissolved in an acetonitrile / toluene porogen at a volume ratio of 5:1 and polymerized at 70 °C for 12 h under argon protection. Subsequent processing was the same as in Example 1 to obtain a polymer-imprinted fluorescent probe.

[0039] Comparative Example

[0040] Comparative Example 1 (without molecular imprinted layer)

[0041] Take 0.2g of nitrogen-doped carbon quantum dots purified in Example 1, and without allyl modification and molecular imprinting polymerization, directly disperse them in water to prepare a fluorescent probe solution.

[0042] Comparative Example 2 (Direct coating without allyl modification)

[0043] 0.2 g of the purified carbon quantum dots from Example 1 were directly mixed with 0.6 g of pyrene template molecules, 2.4 mmol of methacrylic acid, 15 mmol of crosslinking agent, and 0.05 g of initiator for polymerization, omitting the allyl modification step, and the other conditions were the same as in Example 1.

[0044] Comparative Example 3 (Traditional Fluorescent Dye)

[0045] 0.2g of sodium fluorescein salt was used to replace carbon quantum dots, and molecular imprinting polymerization was carried out with pyrene template molecules, functional monomers, crosslinking agents, and initiators in the same proportion as in Example 1 to prepare organic fluorescent dye molecular imprinted probes.

[0046] Comparative Example 4 (Physically Hybrid Non-Core-Shell Structure)

[0047] Nitrogen-doped carbon quantum dots (same as in Example 1) and pyrene molecularly imprinted polymer (without carbon quantum dots) were prepared separately. The two were physically mixed at a mass ratio of 1:3 and ultrasonically dispersed for 30 min.

[0048] Comparative Example 5 (Excessively Thick Imprint Layer)

[0049] The molecular weight ratio of allylated carbon quantum dots to template was adjusted to 1:8, the amount of functional monomer was increased to 5.0 mmol, and the amount of crosslinking agent was increased to 30 mmol, which significantly increased the thickness of the imprinted layer. The other conditions were the same as in Example 1.

[0050] The test results are shown in Tables 1-3 below:

[0051] Table 1 (Comparison of Fluorescence Performance and Detection Sensitivity)

[0052]

[0053] Table 2 Comparison of selectivity coefficients (with pyrene as the detection target)

[0054]

[0055] Table 3 (Comparison of Stability and Reusability)

[0056]

[0057]

[0058] Conclusion: The probes prepared in Examples 1-5 maintained the high quantum yield characteristics of the carbon quantum dot core. At the same time, the uniform and controllable growth of the molecularly imprinted polymer layer was achieved through allyl modification. The constructed core-shell structure reduced the detection limit to micrograms per liter and shortened the response time to the minute scale, which is far superior to Comparative Examples 2-5. Compared with the carbon quantum dots of Comparative Example 1, the probes of this invention exhibit excellent selectivity due to the presence of surface imprinted cavities. The response value to polycyclic aromatic hydrocarbons is close to 1.0, while the interference rate of benzene series compounds, heavy metal ions and surfactants is controlled within 5%. The selectivity coefficient is improved by 3-4 times, which solves the key problem of selectivity loss when there is no imprinted layer. Table 3 shows that the fluorescence retention rate of the probe of this invention remained stable at over 90% under continuous illumination, cyclic use, wide pH range, and long-term storage conditions, significantly better than the performance degradation caused by weak binding or excessive thickness of the imprinted layer in Comparative Examples 2-5. This demonstrates that allyl chemical bonding and optimized imprinted layer thickness are crucial for maintaining the stability of the core-shell structure. Comparative Example 3, using traditional fluorescent dyes, exhibited a quantum yield of less than 20% and extremely poor stability, further verifying the irreplaceable nature of carbon quantum dots as the fluorescent core. In summary, Example 1 demonstrated the best overall performance, with all indicators reaching optimal levels. This indicates that the present invention, through synergistic innovation in carbon quantum dot synthesis, surface allylation, and molecular imprinting polymerization, successfully solved the technical problems of insufficient selectivity, poor stability, slow response, and weak anti-interference ability of fluorescent probes in the prior art, achieving a synergistic improvement in the sensitivity, specificity, and practicality of polycyclic aromatic hydrocarbon detection in industrial wastewater.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater, characterized by, The method comprises the following steps: dissolving carbon source and nitrogen source in deionized water to form a mixed solution; transferring the mixed solution to a hydrothermal reactor for heat treatment to obtain a nitrogen-doped carbon quantum dot primary product; dialysis purification of the primary product to obtain purified nitrogen-doped carbon quantum dots; surface allyl modification of the purified nitrogen-doped carbon quantum dots using an allyl-containing silane coupling agent to obtain allylated carbon quantum dots; dissolving the allylated carbon quantum dots, polycyclic aromatic hydrocarbon template molecules, functional monomers, crosslinking agents and initiators in a porogen to form a polymerization system; polymerization of the polymerization system under a protective atmosphere to form a molecularly imprinted polymer layer on the surface of the carbon quantum dots, thereby obtaining a core-shell structure composite; removal of the template molecules in the core-shell structure composite by Soxhlet extraction to finally obtain a fluorescent probe of molecularly imprinted polymer-coated carbon quantum dots.

2. The method according to claim 1, wherein the method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater is characterized by, The carbon source is at least one selected from citric acid, glucose and ascorbic acid, the nitrogen source is at least one selected from ethylenediamine and triethylamine, and the molar ratio of the carbon source to the nitrogen source is 1:1-1:5, and the concentration of the carbon source in the mixed solution is 0.1-0.5 mol / L.

3. The method according to claim 1, wherein the method comprises the following steps: 1) synthesizing the fluorescent probe; 2) purifying the fluorescent probe; 3) dissolving the fluorescent probe in a solvent; 4) detecting the fluorescent probe in the industrial wastewater. The heat treatment temperature in the hydrothermal reactor is set to 180-220℃, the heat treatment time is controlled to 6-12h, and the heating rate is controlled to 5-10℃ / min, and the reaction is naturally cooled to 25℃ after the reaction is completed.

4. The method according to claim 1, wherein the method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater is characterized by, The dialysis purification uses a dialysis bag with a molecular weight cut-off of 500-1000Da, the dialysis time is 24-48h, the dialysis medium is deionized water, and the water change frequency during dialysis is not less than 5 times.

5. The method according to claim 1, wherein the method is characterized by, The silane coupling agent used in the surface allyl modification is 3-allyloxypropyltrimethoxysilane or allyltriethoxysilane, the mass ratio of the silane coupling agent to the purified nitrogen-doped carbon quantum dots is 1:5-1:10, and the modification reaction is carried out at 60-80℃ for 4-8h.

6. The method according to claim 1, wherein the method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater is characterized by, The polycyclic aromatic hydrocarbon template molecules are pyrene, phenanthrene or anthracene, the functional monomers are methacrylic acid or acrylamide, the crosslinking agent is ethylene glycol dimethacrylate, the initiator is azobisisobutyronitrile, and the porogen is a mixed solvent of acetonitrile and toluene with a volume ratio of 3:1-5:

1.

7. The method according to claim 1, wherein the method comprises the following steps: 1) synthesizing the fluorescent probe; 2) purifying the fluorescent probe; 3) dissolving the fluorescent probe in a solvent; 4) detecting the fluorescent probe in the industrial wastewater. The mass ratio of the allylated carbon quantum dots to the template molecules is 1:2-1:5, the molar ratio of the functional monomers to the template molecules is 4:1-8:1, the molar ratio of the crosslinking agent to the functional monomers is 5:1-10:1, and the amount of the initiator is 1%-3% of the total mass of the functional monomers and the crosslinking agent.

8. The method according to claim 1, wherein the method comprises the following steps: 1) synthesizing the fluorescent probe; 2) purifying the fluorescent probe; 3) dissolving the fluorescent probe in a solvent; 4) detecting the fluorescent probe in the industrial wastewater. The polymerization reaction is carried out under nitrogen or argon protection, the reaction temperature is set to 60-70℃, the reaction time is 12-24h, and the product is washed with anhydrous ethanol for 3-5 times after the reaction is completed, and then vacuum dried at 50℃ for 12h.

9. The method according to claim 1, wherein the method for preparing a fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater is characterized by, The solvent used in the Soxhlet extraction is a mixed solution of methanol and acetic acid with a volume ratio of 9:1-8:2, the extraction temperature is 80-85℃, the extraction time is 24-36h, the product is washed with deionized water to neutral after extraction, and then vacuum dried at 40℃ for 24h, the particle size of the finally obtained fluorescent probe is 50-200nm, the quantum yield is ≥35%, and the detection limit of polycyclic aromatic hydrocarbons is ≤5μg / L.

10. A fluorescent probe for detecting polycyclic aromatic hydrocarbons in industrial wastewater, which is produced by the method according to any one of claims 1 to 9, characterized in that, The probe has a core-shell structure of a carbon quantum dot core and a molecular imprinting polymer shell, the diameter of the carbon quantum dot core is 5-10 nm, the thickness of the molecular imprinting polymer shell is 20-95 nm, the surface has imprinting cavities complementary to the size, shape and functional groups of polycyclic aromatic hydrocarbon molecules, emits blue fluorescence with a wavelength of 420-460 nm under excitation of 365 nm ultraviolet light, produces a fluorescence quenching response after binding with polycyclic aromatic hydrocarbons, the quenching efficiency is greater than or equal to 85%, the fluorescence intensity fluctuation is less than or equal to ± 5% in the pH range of 5-9, and the anti-interference ratio of benzene series, heavy metal ions and anionic surfactants is greater than or equal to 90%.

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