Aerogel composite material, preparation method thereof and application of aerogel composite material in detection of gas-phase nicotine in surface enhanced Raman spectroscopy

Abstract

The invention relates to an aerogel composite material, a preparation method thereof and application of the aerogel composite material to detection of gas-phase nicotine in surface enhanced Raman spectroscopy, and belongs to the technical field of tobacco detection. The preparation method of the aerogel composite material comprises the following steps: carrying out Schiff base reaction on 2, 5-diaminobenzene sulfonic acid and trialdehyde phloroglucinol under the action of a catalyst to obtain a covalent organic framework material; mixing and reacting the covalent organic framework material with chloroauric acid and silver nitrate in water in sequence to obtain a covalent organic framework material loaded with gold and silver; mixing and reacting the covalent organic framework material loaded with gold and silver, chitosan and trialdehyde phloroglucinol in a solvent to obtain hydrogel, and freeze-drying the hydrogel to obtain the aerogel composite material. The aerogel composite material obtained by the invention is porous, has strong adsorption capacity to nicotine and good surface enhanced Raman spectrum enhancement performance to nicotine, and can realize sensitive detection of gas-phase nicotine.

Description

Technical Field

[0001] The invention relates to an aerogel composite material and a preparation method thereof and application in detecting gas-phase nicotine in surface enhanced Raman spectroscopy, belonging to the technical field of tobacco detection. Background Art

[0002] Nicotine is an alkaloid found in Solanaceae plants that can stimulate the release of neurotransmitters, thereby regulating emotions. When smoking or using tobacco products, nicotine quickly enters the blood circulation through the lungs and then passes to the brain, stimulating the central nervous system to produce a series of physiological and psychological effects, including refreshing, improving attention, and enhancing emotions. However, due to its addictiveness, long-term use of tobacco products may lead to physical and mental health problems. Therefore, the detection of trace amounts of nicotine is of great significance to human health. In addition to detecting nicotine in gaseous media such as smoke, the detection of nicotine in liquid samples such as environmental water samples, saliva, and urine is also a concern in the fields of environmental monitoring and disease diagnosis. At present, the main detection methods for nicotine include liquid / gas chromatography, fluorescence determination, capillary electrophoresis, etc. However, these technical means have complicated sample preparation processes.

[0003] Surface-enhanced Raman spectroscopy has the advantages of high detection sensitivity, strong selectivity, and easy miniaturization of equipment, and has received extensive attention in the fields of food safety, environmental protection, and medical testing. However, the common surface-enhanced Raman spectroscopy detection substrate materials have weak chemical affinity for nicotine and low detection sensitivity, and cannot be used for the detection of gas-phase nicotine. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing an aerogel composite material, which can solve the problem that the current surface enhanced Raman spectroscopy detection substrate material has weak chemical affinity for nicotine and cannot be used for gas phase nicotine detection.

[0005] The second object of the present invention is to provide an aerogel composite material, which can solve the problem that the current surface enhanced Raman spectroscopy detection substrate material has weak chemical affinity for nicotine and cannot be used for gas phase nicotine detection.

[0006] The third object of the present invention is to provide an application of an aerogel composite material in detecting gas-phase nicotine in surface enhanced Raman spectroscopy, which can solve the problem that the current surface enhanced Raman spectroscopy detection substrate material has weak chemical affinity for nicotine and cannot be used for gas-phase nicotine detection.

[0007] In order to achieve the above objectives, the technical solution adopted by the method for preparing the aerogel composite material of the present invention is:

[0008] A method for preparing an aerogel composite material comprises the following steps:

[0009] (1) 2,5-diaminobenzenesulfonic acid and trialdehyde phloroglucinol are subjected to a Schiff base reaction in the presence of a catalyst to obtain a covalent organic framework material;

[0010] (2) mixing the covalent organic framework material and chloroauric acid in water, and then adding a reducing agent and silver nitrate to carry out a mixing reaction to obtain a covalent organic framework material loaded with gold and silver;

[0011] (3) mixing the gold-silver loaded covalent organic framework material, chitosan and trialdehyde phloroglucinol in a solvent to obtain a hydrogel, and then freeze-drying the hydrogel to obtain an aerogel composite material.

[0012] The preparation method of the aerogel composite material of the present invention is to load gold and silver nanoparticles on the covalent organic framework material by a step-by-step reduction method, and then carry out a gelation reaction with chitosan to obtain an aerogel composite material. The aerogel composite material obtained by the present invention has the characteristics of being porous and having a strong adsorption capacity for nicotine, wherein the sulfonic acid group covalent organic framework material can selectively adsorb nicotine, and the gold and silver nanoparticles are closely distributed, generating a large number of localized surface plasma electromagnetic field "hot spots", and having good surface enhanced Raman spectroscopy enhancement performance. When the aerogel composite material prepared by the present invention is used as a surface enhanced Raman spectroscopy detection substrate material, the aerogel composite material first selectively adsorbs nicotine, and then enhances the nicotine molecular signal through the loaded nano-gold and silver, thereby realizing sensitive detection of gas-phase nicotine.

[0013] Preferably, the molar ratio of 2,5-diaminobenzenesulfonic acid to trialdehyde phloroglucinol in step (1) is 0.45:0.35.

[0014] Preferably, the catalyst is p-toluenesulfonic acid; the molar ratio of 2,5-diaminobenzenesulfonic acid, trialdehyde phloroglucinol and the catalyst in step (1) is 0.45:0.35:2.5.

[0015] Preferably, the temperature of the Schiff base reaction is 170° C. and the time is 10 min.

[0016] Preferably, for every 2.5 mg of the covalent organic framework material, the mass of the chloroauric acid used is 0.5 mg, and the mass of the silver nitrate is 2.1-12.8 mg.

[0017] Preferably, the preparation method of the covalent organic framework material loaded with gold and silver comprises the following steps: first, adding chloroauric acid solution to the covalent organic framework material dispersion for a first mixing reaction, then adding a reducing agent and a silver nitrate solution to the system after the first mixing reaction for a second mixing reaction, solid-liquid separation, and drying to obtain the covalent organic framework material loaded with gold and silver; the mass fraction of the covalent organic framework material dispersion is 0.25%; the mass fraction of the chloroauric acid solution is 1%, the addition rate of the chloroauric acid solution is 0.2 mL / min, and the time of the first mixing reaction is 30 min; the concentration of the silver nitrate solution is 10 mmol / L, the addition rate of the silver nitrate solution is 0.5 mL / min, the temperature of the second mixing reaction is 70° C., and the time is 1 h; the reducing agent is sodium citrate dihydrate.

[0018] Preferably, the mass ratio of the covalent organic framework material loaded with gold and silver, chitosan and trialdehyde phloroglucinol in step (3) is 6:10:2.

[0019] Preferably, the preparation method of the hydrogel is as follows: a covalent organic framework material loaded with gold and silver, a chitosan solution and a trialdehyde phloroglucinol solution are mixed to obtain a hydrogel; the chitosan solution consists of chitosan and acetic acid, and the concentration of the chitosan solution is 0.16 mol / L; the trialdehyde phloroglucinol solution consists of trialdehyde phloroglucinol and water, and the concentration of the trialdehyde phloroglucinol solution is 10 g / L; for every 6 mg of the covalent organic framework material loaded with gold and silver, 800 μL of chitosan solution and 200 μL of trialdehyde phloroglucinol solution are used.

[0020] The technical solution adopted by the aerogel composite material of the present invention is:

[0021] An aerogel composite material prepared by the method for preparing the aerogel composite material as described above.

[0022] The aerogel composite material of the present invention is composited by a covalent organic framework material loaded with gold and silver and chitosan. The sulfonic acid covalent organic framework material can selectively adsorb nicotine, and the loaded nano-gold and silver can enhance the nicotine molecular signal. The aerogel composite material of the present invention can be used as a surface enhanced Raman spectroscopy detection substrate material for Raman spectroscopy detection and analysis of gas-phase nicotine.

[0023] The technical solution adopted by the application of the aerogel composite material of the present invention in detecting gas-phase nicotine in surface enhanced Raman spectroscopy is:

[0024] An application of the aerogel composite material as described above to detecting gas-phase nicotine in surface enhanced Raman spectroscopy.

[0025] The aerogel composite material of the present invention is porous and has a strong ability to adsorb nicotine. When used as a surface enhanced Raman spectroscopy detection substrate material, the sulfonic acid covalent organic skeleton material in the aerogel material can selectively adsorb nicotine, and the loaded nano-gold and silver can enhance the nicotine molecular signal, thereby realizing sensitive detection of gas-phase nicotine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The microstructure of the covalent organic framework material loaded with gold and silver prepared in Example 1 and the appearance of the prepared aerogel composite material;

[0027] Figure 2 This is a schematic diagram of the detection results of the covalent organic framework material loaded with precious metals prepared in Examples 1-5 detecting a nicotine solution with a concentration of 50 mg / L;

[0028] Figure 3 This is a picture of the device used for gas phase nicotine detection;

[0029] Figure 4 Raman spectrum of aerogel composite material used for gas-phase nicotine detection. DETAILED DESCRIPTION

[0030] The preparation method of the aerogel composite material of the present invention is a pioneering invention. The present invention loads gold and silver nanoparticles on a covalent organic framework material, so that a synergistic effect is generated between the covalent organic framework material and the noble metal nanoparticles. On the one hand, the covalent organic framework material exhibits high adsorption performance for nicotine, shortens the distance between nicotine and the noble metal nanoparticles, and then effectively utilizes the surface plasma resonance effect of the noble metal nanoparticles. On the other hand, the gold-silver nanoparticles with a core-shell structure can produce a bimetallic synergistic effect and improve the activity of surface enhanced Raman spectroscopy. The aerogel composite material of the present invention can achieve adsorption and sensitive detection of nicotine in smoke.

[0031] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0032] 1. The specific embodiment of the method for preparing the aerogel composite material of the present invention is as follows:

[0033] Example 1

[0034] The method for preparing the aerogel composite material of this embodiment specifically comprises the following steps:

[0035] (1) Synthesis of covalent organic framework material TpPa-SO3H using grinding method

[0036] 2,5-Diaminobenzenesulfonic acid (0.45mmol, 84.7mg) and p-toluenesulfonic acid (2.5mmol, 430.5mg) were placed in a mortar and ground for 15min, then trialdehyde pyrogallol (0.35mmol, 74.2mg) and 20μL ultrapure water were added, and the grinding was continued for 15min. Then, the ground material was placed in an oven and heated at 170°C for 10min to obtain a powdered covalent organic framework material named TpPa-SO3H.

[0037] (2) Preparation of TpPa-SO3H-Au@Ag by step-by-step reduction method

[0038] 2.5 mg of the covalent organic framework material TpPa-SO3H prepared in step (1) was dispersed in 1 mL of ultrapure water and ultrasonicated for 5 min to obtain a covalent organic framework material dispersion. Then, chloroauric acid solution (mass fraction of 1%, volume of 50 μL) was added to the covalent organic framework material dispersion at a rate of 0.2 mL / min under vigorous stirring, and the reaction was stirred for 30 min. Then, a reducing agent sodium citrate dihydrate (sodium citrate dihydrate addition amount of 25 mg) was added to the system after stirring the reaction, and then AgNO3 solution (concentration of 10 mmol / L, volume of 0.95 mL) was added at a rate of 0.5 mL / min. The reaction was heated and stirred at 70°C for 1 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a covalent organic framework material loaded with gold and silver, which was named TpPa-SO3H-Au@Ag.

[0039] (3) Preparation of aerogel composites

[0040] Chitosan was dissolved in 800 μL of acetic acid to obtain a chitosan solution with a concentration of 0.16 mol / L. The chitosan solution was vortexed and ultrasonicated. Then, the covalent organic framework material TpPa-SO3H-Au@Ag (6 mg) prepared in step (2) was added to the chitosan solution. After vortexing evenly, a trialdehyde pyrogallol aqueous solution (volume 200 μL, concentration 10 g / L) was added. The aqueous solution was vortexed until it gelled. The solution was placed in hot water at a temperature of 50°C for 20 minutes and then allowed to stand at room temperature for 24 hours to obtain a hydrogel. The hydrogel was freeze-dried at -40°C for 24 hours to obtain an aerogel composite material, named TpPa-SO3H-Au@Ag / CS.

[0041] Example 2

[0042] The method for preparing the aerogel composite material of this embodiment specifically comprises the following steps:

[0043] (1) This step is the same as step (1) of Example 1.

[0044] (2) Preparation of TpPa-SO3H-Au@Ag by step-by-step reduction method

[0045] 2.5 mg of the covalent organic framework material TpPa-SO3H prepared in step (1) was dispersed in 1 mL of ultrapure water and ultrasonicated for 5 min to obtain a covalent organic framework material dispersion. Then, chloroauric acid solution (mass fraction of 1%, volume of 50 μL) was added to the covalent organic framework material dispersion at a rate of 0.2 mL / min under vigorous stirring, and the reaction was stirred for 30 min. Then, a reducing agent sodium citrate dihydrate (sodium citrate dihydrate addition amount of 25 mg) was added to the system after stirring the reaction, and then AgNO3 solution (concentration of 10 mmol / L, volume of 1.9 mL) was added at a rate of 0.5 mL / min. The reaction was heated and stirred at 70°C for 1 h. After the reaction was completed, it was filtered, washed, and dried to obtain a covalent organic framework material loaded with gold and silver, named TpPa-SO3H-Au@Ag.

[0046] (3) This step is the same as step (3) of Example 1.

[0047] Example 3

[0048] The method for preparing the aerogel composite material of this embodiment specifically comprises the following steps:

[0049] (1) This step is the same as step (1) of Example 1.

[0050] (2) Preparation of TpPa-SO3H-Au@Ag by step-by-step reduction method

[0051] 2.5 mg of the covalent organic framework material TpPa-SO3H prepared in step (1) was dispersed in 1 mL of ultrapure water and ultrasonicated for 5 min to obtain a covalent organic framework material dispersion. Then, chloroauric acid solution (mass fraction of 1%, volume of 50 μL) was added to the covalent organic framework material dispersion at a rate of 0.2 mL / min under vigorous stirring, and the reaction was stirred for 30 min. Then, a reducing agent sodium citrate dihydrate (sodium citrate dihydrate addition amount of 25 mg) was added to the system after stirring the reaction, and then AgNO3 solution (concentration of 10 mmol / L, volume of 3.81 mL) was added at a rate of 0.5 mL / min. The reaction was heated and stirred at 70°C for 1 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a covalent organic framework material loaded with gold and silver, named TpPa-SO3H-Au@Ag.

[0052] (3) This step is the same as step (3) of Example 1.

[0053] Example 4

[0054] The method for preparing the aerogel composite material of this embodiment specifically comprises the following steps:

[0055] (1) This step is the same as step (1) of Example 1.

[0056] (2) Preparation of TpPa-SO3H-Au@Ag by step-by-step reduction method

[0057] 2.5 mg of the covalent organic framework material TpPa-SO3H prepared in step (1) was dispersed in 1 mL of ultrapure water and ultrasonicated for 5 min to obtain a covalent organic framework material dispersion. Then, chloroauric acid solution (mass fraction of 1%, volume of 50 μL) was added to the covalent organic framework material dispersion at a rate of 0.2 mL / min under vigorous stirring, and the reaction was stirred for 30 min. Then, a reducing agent sodium citrate dihydrate (sodium citrate dihydrate addition amount of 25 mg) was added to the system after stirring the reaction, and then AgNO3 solution (concentration of 10 mmol / L, volume of 5.72 mL) was added at a rate of 0.5 mL / min. The reaction was heated and stirred at 70°C for 1 h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain a covalent organic framework material loaded with gold and silver, named TpPa-SO3H-Au@Ag.

[0058] (3) This step is the same as step (3) of Example 1.

[0059] Example 5

[0060] The method for preparing the aerogel composite material of this embodiment specifically comprises the following steps:

[0061] (1) This step is the same as step (1) of Example 1.

[0062] (2) Preparation of TpPa-SO3H-Au@Ag by step-by-step reduction method

[0063] 2.5 mg of the covalent organic framework material TpPa-SO3H prepared in step (1) was dispersed in 1 mL of ultrapure water and ultrasonicated for 5 min to obtain a covalent organic framework material dispersion. Then, chloroauric acid solution (mass fraction of 1%, volume of 50 μL) was added to the covalent organic framework material dispersion at a rate of 0.2 mL / min under vigorous stirring, and the reaction was stirred for 30 min. Then, a reducing agent sodium citrate dihydrate (sodium citrate dihydrate addition amount of 25 mg) was added to the system after stirring the reaction, and then AgNO3 solution (concentration of 10 mmol / L, volume of 7.62 mL) was added at a rate of 0.5 mL / min. The reaction was heated and stirred at 70°C for 1 h. After the reaction was completed, it was filtered, washed, and dried to obtain a covalent organic framework material loaded with gold and silver, named TpPa-SO3H-Au@Ag.

[0064] (3) This step is the same as step (3) of Example 1.

[0065] 2. Specific embodiments of the aerogel composite material of the present invention are as follows:

[0066] The aerogel composite material of this embodiment is an aerogel composite material prepared by the preparation method of any aerogel composite material in Embodiments 1-5.

[0067] 3. Specific examples of the application of the aerogel composite material of the present invention in detecting gas-phase nicotine in surface enhanced Raman spectroscopy are as follows:

[0068] The aerogel composite material prepared by the preparation method of any aerogel composite material in Examples 1-5 is used to detect gas-phase nicotine in surface enhanced Raman spectroscopy.

[0069] Experimental Example 1

[0070] In this experimental example, a transmission electron microscope (TEM) was used to analyze the microstructure of the prepared covalent organic framework material loaded with gold and silver. The specific method is as follows: the covalent organic framework material sample loaded with gold and silver prepared in Example 2 was dispersed in ultrapure water, and then dripped onto a 200-mesh copper grid coated with a carbon film after ultrasonic dispersion. After drying, a TEM test was performed. The microstructure of the covalent organic framework material loaded with gold and silver and the aerogel composite material prepared in Example 2 is shown in FIG. Figure 1 As shown ( Figure 1 The lower right corner of the picture shows the appearance of the aerogel composite material). Figure 1 It can be seen that the silver nanoparticles are evenly distributed in the gel network and the distance between the silver nanoparticles is relatively close, which is conducive to the generation of surface enhanced Raman spectroscopy enhancement hotspots.

[0071] Experimental Example 2

[0072] This experimental example uses the covalent organic framework material loaded with precious metals prepared in Examples 1-5 to detect nicotine in a nicotine solution, and the concentration of the nicotine solution is 50 mg / L. The specific test method is as follows: 15 μL of the covalent organic framework material dispersion loaded with precious metals is stirred and mixed with 1 mL of nicotine solution for 10 minutes, and then the mixed liquid is dripped onto a glass slide and placed under the fiber optic Raman spectrometer probe for Raman detection. The detection conditions of the Raman spectrometer are as follows: the laser wavelength is 785 nm, the laser intensity is 50 mW, the integration time is 1 s, and the number of integrations is 20 times. Different sampling points are randomly selected for each sample, and at least 10 samples are collected. The obtained spectra are averaged to obtain the final Raman spectrum of the sample. The detection results of the covalent organic framework material loaded with precious metals prepared in Examples 1-5 for detecting a nicotine solution with a concentration of 50 mg / L are shown as follows. Figure 2As shown. Since the molar ratios of the gold element in the chloroauric acid solution and the silver element in the AgNO3 solution in Examples 1-5 are 1:10, 1:15, 1:30, 1:45, and 1:60, respectively, Figure 2 1:10, 1:15, 1:30, 1:45, and 1:60 represent the covalent organic framework materials loaded with precious metals prepared in Examples 1-5, respectively.

[0073] Depend on Figure 2 It can be seen that as the molar ratio of gold in chloroauric acid solution to silver in AgNO3 solution increases from 1:10 to 1:60, the Raman spectrum signal of nicotine increases first and then decreases, and the best enhancement effect is obtained when the molar ratio is 1:15. + The dosage is very important for producing a better enhancement effect. When the molar ratio of gold element in chloroauric acid solution and silver element in AgNO3 solution is 1:15, the prepared covalent organic framework material loaded with precious metals has the best surface enhanced Raman enhancement performance.

[0074] Experimental Example 3

[0075] This experiment uses the Figure 3 The device shown is used to detect gas-phase nicotine. The detection steps are as follows: light a cigarette, use a peristaltic pump to simulate human smoking, place an aerogel composite material in the tube for inhaling smoke, and after the cigarette is completely burned, take out the aerogel composite material and place it on a glass slide, and then place the glass slide under the fiber optic Raman spectrometer probe for Raman detection. The detection conditions of the Raman spectrometer are as follows: laser wavelength 785nm, laser intensity 50mW, integration time 1s, and integration times 20 times. Different sampling points are randomly selected for each sample, and the samples are collected at least 10 times. The obtained spectra are averaged to obtain the final Raman spectrum of the sample to achieve quantitative detection of gas-phase nicotine. The results of using the aerogel composite material prepared in Example 1 for gas-phase nicotine detection are shown in the figure. Figure 4 shown. Figure 4 In the figure, the blue spectrum is the Raman signal spectrum of the aerogel composite material, and the red spectrum is the Raman signal spectrum of the aerogel material after absorbing nicotine in the smoke. By comparing the blue spectrum and the red spectrum, it can be seen that at 1075cm -1 The characteristic Raman peak of nicotine appeared at the position, indicating that the aerogel composite material can realize the detection of nicotine in smoke.

Claims

1. A method for preparing an aerogel composite material, characterized in that: The following steps are involved: (1) 2,5-diaminobenzenesulfonic acid and trialdehyde phloroglucinol are subjected to a Schiff base reaction in the presence of a catalyst to obtain a covalent organic framework material; (2) mixing the covalent organic framework material and chloroauric acid in water, and then adding a reducing agent and silver nitrate to carry out a mixing reaction to obtain a covalent organic framework material loaded with gold and silver; (3) mixing the gold-silver loaded covalent organic framework material, chitosan and trialdehyde phloroglucinol in a solvent to obtain a hydrogel, and then freeze-drying the hydrogel to obtain an aerogel composite material.

2. The method for preparing an aerogel composite material according to claim 1, characterized in that: The molar ratio of 2,5-diaminobenzenesulfonic acid to trialdehyde phloroglucinol in step (1) is 0.45:0.

35.

3. The method for preparing the aerogel composite material according to claim 1, characterized in that: The catalyst is p-toluenesulfonic acid; the molar ratio of 2,5-diaminobenzenesulfonic acid, trialdehyde phloroglucinol and the catalyst in step (1) is 0.45:0.35:2.

5.

4. The method for preparing an aerogel composite material according to claim 3, characterized in that: The temperature of the Schiff base reaction is 170° C. and the time is 10 min.

5. The method for preparing an aerogel composite material according to claim 1, characterized in that: For every 2.5 mg of the covalent organic framework material, the mass of the chloroauric acid used is 0.5 mg, and the mass of the silver nitrate is 2.1 to 12.8 mg.

6. The method for preparing an aerogel composite material according to any one of claims 1 to 5, characterized in that: The preparation method of a covalent organic framework material loaded with gold and silver comprises the following steps: firstly, adding a chloroauric acid solution into a covalent organic framework material dispersion liquid to carry out a first mixing reaction, then adding a reducing agent and a silver nitrate solution into the system after the first mixing reaction to carry out a second mixing reaction, solid-liquid separation, and drying to obtain the covalent organic framework material loaded with gold and silver; the mass fraction of the covalent organic framework material dispersion liquid is 0.25%; the mass fraction of the chloroauric acid solution is 1%, the adding speed of the chloroauric acid solution is 0.2 mL / min, and the time of the first mixing reaction is 30 min; the concentration of the silver nitrate solution is 10 mmol / L, the adding speed of the silver nitrate solution is 0.5 mL / min, the temperature of the second mixing reaction is 70°C, and the time is 1 h; the reducing agent is sodium citrate dihydrate.

7. The method for preparing an aerogel composite material according to any one of claims 1 to 5, characterized in that: The mass ratio of the covalent organic framework material loaded with gold and silver, chitosan and trialdehyde phloroglucinol in step (3) is 6:10:

2.

8. The method for preparing an aerogel composite material according to any one of claims 1 to 5, characterized in that: The preparation method of the hydrogel is as follows: a covalent organic framework material loaded with gold and silver, a chitosan solution and a trialdehyde phloroglucinol solution are mixed to obtain a hydrogel; the chitosan solution consists of chitosan and acetic acid, and the concentration of the chitosan solution is 0.16 mol / L; the trialdehyde phloroglucinol solution consists of trialdehyde phloroglucinol and water, and the concentration of the trialdehyde phloroglucinol solution is 10 g / L; for every 6 mg of the covalent organic framework material loaded with gold and silver, 800 μL of the chitosan solution and 200 μL of the trialdehyde phloroglucinol solution are used.

9. An aerogel composite material prepared by the method for preparing an aerogel composite material according to any one of claims 1 to 8.

10. Use of the aerogel composite material according to claim 9 for detecting gas-phase nicotine in surface enhanced Raman spectroscopy.

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