A hydrophobized thiol-modified silver nanostar paper-based material and its preparation method and application
By replacing citrate ions on the surface of silver nanostar sol and performing thiol modification, combined with hydrophobic treatment, an efficient hydrophobicized thiol-modified silver nanostar paper-based material was prepared, which solved the problem of low sensitivity in traditional detection methods and achieved rapid and simple detection of perchlorate.
Patent Information
- Application Number
- CN202411862231.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2044-12-17
AI Technical Summary
Traditional silver nanostar materials have the problems of significantly reduced sensitivity and low Raman signal when detecting perchlorate, mainly because the electrostatic repulsion between citrate anions and perchlorate anions cannot effectively combine, resulting in poor detection effect.
The citrate ions on the surface of the silver nanostar sol were replaced by NaCl, and thiol modification was carried out using 4-aminothiophenol. The modified silver nanostars were loaded on filter paper and hydrophobized with polydimethylsiloxane to form a SERS detection substrate with high-density hotspots and high electrostatic binding ability.
It achieves rapid and simple detection of perchlorate in water bodies, with significantly improved sensitivity and accuracy. The detection time is completed within about 5 seconds, making it suitable for rapid screening of perchlorate content.
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Figure CN119711248B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of perchlorate detection, and particularly relates to a hydrophobized thiol-modified silver nanostar paper-based material, a preparation method and an application thereof. Background Art
[0002] Perchlorate is a new type of persistent environmental trace pollutant, composed of the tetrahedral perchlorate anion (ClO4-). The radius and charge of the perchlorate ion are very similar to those of the iodide ion. It competes with iodide for entry into the human thyroid gland, interfering with iodine absorption and affecting human development, particularly embryos, pregnant and lactating women, and children.
[0003] Perchlorate is highly soluble, diffuses rapidly in the environment, is highly stable, and is difficult to degrade. During irrigation, it can migrate into water or soil, where it can be absorbed and accumulated by plants. In recent years, reports have shown that varying concentrations of perchlorate have been detected in various foods, including milk powder, grains, meat, beverages, drinking water, and seafood. There are clear safety limits for perchlorate in drinking water.
[0004] Perchlorate, a common environmental pollutant primarily found in water, has garnered significant attention for its detection. X-ray fluorescence, ion chromatography, ion chromatography-tandem mass spectrometry (IC-MS / MS), liquid chromatography-tandem mass spectrometry (LC-MS / MS), surface-enhanced Raman scattering (SERS), and ion-selective electrodes have been reported for perchlorate detection. IC-MS / MS and LC-MS / MS are commonly used in routine laboratory analysis of perchlorate in food and water due to their high sensitivity, accuracy, and robust interference tolerance. However, these instrument-based methods are expensive, require long test cycles, and require specialized personnel.
[0005] SERS requires the use of a detection substrate to detect perchlorate. Prior to detection, a water sample must be dripped onto the substrate, where it is electrostatically bound to the perchlorate anion, allowing the perchlorate to be detected. Silver nanostars are nanoparticles composed of a central body and several arms or tips extending from the central body. The characteristic morphology of the multiple tips gives the nanostars a good localized surface plasmon effect, often resulting in higher sensitivity than rod-shaped, spherical, or dimer particles. However, traditional methods for synthesizing silver nanostars incorporate sodium citrate as a reducing agent and stabilizer. Consequently, the citrate anions modified on the surface of the AgNS structure are unable to effectively bind to the AgNS due to electrostatic repulsion with the perchlorate anions, preventing them from reaching the SERS detection hotspot, significantly reducing sensitivity. Furthermore, perchlorate itself cannot bind to the AgNS structure through other interactions, resulting in an extremely low Raman scattering cross section and a correspondingly low Raman signal. Summary of the Invention
[0006] In response to the shortcomings of the existing technology, the present invention provides a hydrophobized thiol-modified silver nanostar paper-based material, a preparation method, and an application thereof, to solve the problems of significantly reduced sensitivity in perchlorate detection and low Raman signal. The method is simple and reliable. By synthesizing a highly plasmonically active AgNS structure, modifying it with thiol, loading it on a paper base, and hydrophobizing it, trace and rapid detection of perchlorate in water can be achieved.
[0007] The present invention is achieved through the following technical solutions:
[0008] A method for preparing a hydrophobized thiol-modified silver nanostar paper-based material comprises the following steps:
[0009] S1, first using NaCl to replace the citrate modified on the surface of the silver nanostar sol, and then removing excess chloride ions to obtain the replaced silver nanostar sol;
[0010] S2, using 4-aminobenzenethiophenol to perform thiol modification on the replaced silver nanostar sol to obtain thiol-modified silver nanostar sol;
[0011] S3, loading the thiol-modified silver nanostar sol onto filter paper by vacuum filtration to obtain a paper-based substrate, and then hydrophobizing the paper-based substrate using polydimethylsiloxane to obtain a hydrophobized thiol-modified silver nanostar paper-based material.
[0012] A further improvement of the present invention is:
[0013] S1: NaCl was added to the silver nanostar sol solution. The molar ratio of NaCl to silver ions in the silver nanostar sol solution was 30:1. gAfter centrifugal washing under the conditions, the supernatant was removed, and deionized water was added for centrifugal washing to obtain the replaced silver nanostar sol.
[0014] S2 adds the replaced silver nanostar sol solution to the 4-aminothiophenol aqueous solution while stirring to obtain a thiol-modified silver nanostar sol solution. S3 then vacuum filters the thiol-modified silver nanostar sol solution on filter paper to obtain a paper-based substrate.
[0015] The molar ratio of silver ions in the replaced silver nanostar sol solution to 4-aminothiophenol in the 4-aminothiophenol aqueous solution is 200:(1.3-2).
[0016] S2, while stirring, adds the replaced silver nanostar sol solution to the 4-aminobenzenethiol aqueous solution to obtain a mixed solution, and then adjusts the pH of the mixed solution to 1.5-2.5 with 1 M HCl solution, removes the supernatant by centrifugation, and then adds deionized water with the same volume as the supernatant to obtain a thiol-modified silver nanostar sol solution.
[0017] S3: The vacuum degree when the thiol-modified silver nanostar sol is loaded on the filter paper is 0.6-0.8 MPa, and the vacuum filtration is carried out for 2-4 min.
[0018] S3 first dissolves 1.1-1.3 g of PDMS in 25-35 mL of n-hexane to obtain a hydrophobic solution, and then immerses the paper-based substrate in the hydrophobic solution for 8-12 min to obtain a hydrophobized thiol-modified silver nanostar paper-based material.
[0019] S3: immersing the paper-based substrate in a hydrophobic solution for 8-12 minutes, taking it out, and drying it at 60-80° C. for 2.5-3.5 hours to obtain a hydrophobized thiol-modified silver nanostar paper-based material.
[0020] A hydrophobized thiol-modified silver nanostar paper-based material obtained by any one of the above methods for preparing the hydrophobized thiol-modified silver nanostar paper-based material.
[0021] Application of a hydrophobized thiol-modified silver nanostar paper-based material in the rapid screening of perchlorate in water.
[0022] Compared with the prior art, the present invention has the following beneficial technical effects:
[0023] The present invention discloses a method for preparing a hydrophobized thiol-modified silver nanostar paper-based material. The method involves replacing the citrate ions on the surface of the AgNS sol with chloride ions carried by NaCl. After removing excess chloride ions, the material is then thiol-modified by adding positively charged 4-aminothiophenol molecules that can directly covalently bind to the AgNS structure as a linker. This is accomplished by solvent displacement, allowing perchlorate to be adsorbed onto the positively charged surface of the AgNS structure via electrostatic bonding. To facilitate portability and extend shelf life, the AgNS structure is loaded onto filter paper via vacuum filtration to initially form a substrate for SERS detection. Because the cellulose paper-based material is hydrophilic, the contact angle of the sample's aqueous solution on the substrate is very small, even near zero. Consequently, a drop of sample spreads out over a large area on the SERS substrate. However, the laser spot area of the laser Raman spectrometer used for surface-enhanced Raman scattering detection is very small, resulting in the majority of the target substance being located in an undetectable position, resulting in decreased sensitivity. Polydimethylsiloxane has a low surface energy and significant hydrophobic properties due to its repeated non-polar siloxane units, which ultimately forms a SERS substrate with high-density hotspots and high electrostatic binding ability, improving the sensitivity and accuracy of SERS detection, and further enhancing its ability to detect perchlorate.
[0024] Furthermore, by adjusting the pH of the mixture to 1.5-2.5 with 1 M HCl solution, the protonation (positive charge) level of 4-ATP can be maximized, which can enhance the binding effect with perchlorate.
[0025] When the hydrophobic thiol-modified silver nanostar paper-based material of the present invention is used to screen perchlorate in water, compared with traditional methods of determining perchlorate in water, water samples do not require pretreatment. A microliter (about 5 μL) of the analysis sample is simply added dropwise onto the hydrophobic thiol-modified silver nanostar paper-based material as a base, and the sample signal is collected using a laser Raman spectrometer with an exposure time of about 0.5 s. The detection is completed in a total of about 5 s to obtain a Raman spectrum. By observing whether there is a response, it can be determined whether the sample contains perchlorate contaminants. The operation is simple, time-saving, and labor-saving, and the method is suitable for rapid screening of perchlorate content. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 The wave number shift of perchlorate at different concentrations is 937 cm -1 Below is the SERS response (Raman peak) spectrum.
[0027] Figure 2 This is a linear relationship diagram between Raman peak intensity and sodium perchlorate concentration.
[0028] Figure 3 This is a physical picture of the hydrophobized thiol-modified silver nanostar paper-based material obtained in Example 1 of the present invention.
[0029] Figure 4 This is a scanning electron microscope image of the hydrophobized thiol-modified silver nanostar paper-based material obtained in Example 1 of the present invention.
[0030] Figure 5 Raman spectra of 0.1 M 4-ATP aqueous solution and thiol-modified AgNS paper. DETAILED DESCRIPTION
[0031] The principles and advantages of the present invention are explained and illustrated below through specific embodiments so that those skilled in the art can better understand the present invention. The following description is only exemplary and does not limit its content.
[0032] Instrument and reagent description
[0033] FA1004 electronic balance (Shimadzu Philippines Manufacturing Co., Ltd.), BPG-9070A precision blast drying oven (Shanghai Yiheng Scientific Instrument Co., Ltd.), laboratory super deionized water machine (Shanghai Hetai Instrument Co., Ltd.), DXRxi laser confocal Raman imaging spectrometer (Thermo Fisher Scientific, USA), SU8100 high-resolution scanning electron microscope (Bruker, Germany).
[0034] Analytical-grade silver nitrate (AgNO3, >99.8%) was purchased from Xilong Scientific Co., Ltd., and analytical-grade sodium citrate (99.0%), NaOH (96%), 4-aminothiophenol (4-ATP, 98%), hydroxylamine (50 wt% in H2O), and polydimethylsiloxane (average MW = 115,000) were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
[0035] The present invention provides a method for preparing a hydrophobized thiol-modified silver nanostar paper-based material, comprising the following steps:
[0036] Step 1), preparation of silver nanostar (Ag NS) sol at room temperature:
[0037] Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 3-5 minutes. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the above mixed solution at once while stirring. After stirring for 5 minutes, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shaken for 15 min to obtain the AgNS sol solution.
[0038] Step 2), preparation of thiol-modified silver nanostar sol:
[0039] 0.35 g of NaCl was added to 20 ml of AgNS sol solution, and the mixture was shaken and stirred for 30 min. g The mixture was centrifuged under the same conditions for 10 min to displace the citrate ions in the AgNS sol, which could prevent irreversible aggregation and precipitation during subsequent pH adjustment and addition of 4-aminothiol, thus affecting the SERS detection effect. After removing the supernatant (19 ml), 19 ml of deionized water was added and centrifuged once under the same conditions to remove the excess chloride ions in the replaced AgNS sol. 19 mL of supernatant was removed and 19 mL of deionized water was added.
[0040] 20 mL of chloride-exchanged AgNS colloidal solution was added dropwise to a 0.1 mM 4-ATP aqueous solution (1.3 mL-2 mL) while stirring at 1000-1200 rpm. 4-ATP can bind to AgNS through Ag-S bonds. Since perchlorate is an anion, 4-ATP has a certain positive charge when dissolved in water, which allows it to bind to the perchlorate anion through electrostatic adsorption. To further increase the protonation degree of 4-ATP (to carry more positive charge), the pH of the mixture was adjusted to 1.5-2.5 by adding 1 M HCl solution and 800-1200 × g The mixture was centrifuged for 5 min under the above conditions to remove 19 mL of supernatant to remove chloride ions in the solution, and then 19 mL of deionized water was added to prepare a thiol-modified silver nanostar sol solution.
[0041] Step 3), preparation of paper-based silver nanostars:
[0042] The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) with a vacuum filtration bottle at a vacuum degree of 0.6-0.8 MPa for 2-4 min.
[0043] Step 4), hydrophobization of polydimethylsiloxane (PDMS):
[0044] PDMS (1.1-1.3 g) was dissolved in 25-35 mL of n-hexane and stirred for 4 hours to prepare a hydrophobic solution. The resulting paper-based silver nanostars were immersed in the solution for 8-12 minutes to impart hydrophobicity to the silver nanostar paper substrate. The paper-based silver nanostar substrate was then dried at 60-80°C for 2.5-3.5 hours to obtain a hydrophobized thiol-modified silver nanostar paper substrate. Polydimethylsiloxane (PDMS) has repeating non-polar siloxane units, resulting in a low surface energy and significant hydrophobicity. Several microliters of the aqueous solution were dropwise added to the hydrophobized thiol-modified silver nanostar paper substrate, which then served as a substrate for SERS detection.
[0045] Example 1
[0046] Step 1), preparation of silver nanostar (Ag NS) sol at room temperature:
[0047] Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 3 min. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the above mixed solution at once while stirring. After stirring for 5 min, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shaken for 15 min to obtain a solution containing AgNS sol.
[0048] Step 2), preparation of thiol-modified silver nanostar sol:
[0049] 0.35 g of NaCl was added to 20 ml of the solution containing AgNS sol, and the mixture was shaken and stirred for 30 min. g Centrifuge for 10 min under the same conditions, remove 19 mL of supernatant, and add 19 mL of deionized water. Centrifuge once under the same conditions, remove 19 mL of supernatant, and then add 19 mL of deionized water.
[0050] 20 mL of the chloride ion-substituted AgNS colloidal solution was added dropwise to 0.1 mM 4-ATP aqueous solution (1.3 mL) and stirred at 1000 rpm. The pH of the mixture was adjusted to 1.5 by adding 1 M HCl solution and 800 × g The mixture was centrifuged for 5 min under the same conditions, 19 mL of supernatant was removed, and 19 mL of deionized water was added to prepare a thiol-modified silver nanostar sol solution.
[0051] Step 3), preparation of paper-based silver nanostars:
[0052] The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) with a vacuum filtration bottle at a vacuum degree of 0.6 MPa for 4 min.
[0053] Step 4), hydrophobization of polydimethylsiloxane (PDMS):
[0054] PDMS (1.1 g) was dissolved in 25 mL of n-hexane and stirred for 4 h to prepare a hydrophobic solution. The resulting paper-based silver nanostars were immersed in the hydrophobic solution for 8 min and then dried at 60 °C for 3.5 h to obtain the following: Figure 3 The hydrophobized thiol-modified silver nanostar paper-based material shown can be used as a substrate for SERS detection.
[0055] In this example, the modified AgNS sol was placed on a cellulose paper substrate by simple filtration and subjected to hydrophobic treatment. Figure 4 The deposited AgNS structure exhibited an arm-like structure extending from the central body, indicating that the hydrophobized thiol-modified silver nanostar paper-based material was successfully prepared.
[0056] 0.1 M 4-ATP aqueous solution and thiol-modified silver nanostar sol solution were vacuum filtered using a cellulose circular filter paper (5 cm diameter) with a vacuum degree of 0.6 MPa and a filtration time of 4 min. The Raman parameters were tested as follows: Figure 5 It can be seen that 4-ATP is 1078 cm on the AgNS paper substrate. -1 (symmetrical stretching vibration of benzene ring) and 1577 cm -1 The characteristic peak of (benzene ring out-of-plane vibration) was significantly enhanced, indicating that 4-ATP was successfully modified on the AgNS paper-based material.
[0057] Raman parameters
[0058] Excitation wavelength: 532 nm, laser energy 3-5 mW, 50× objective lens, exposure time: 0.5 s, wavenumber scanning range 50-3400 cm -1 , 5 μL of the solution to be analyzed was added dropwise for direct SERS detection.
[0059] Example 2
[0060] Step 1), preparation of silver nanostar (Ag NS) sol at room temperature:
[0061] Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 4 min. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the above mixed solution at once while stirring. After stirring for 5 min, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shaken for 15 min to obtain a solution containing AgNS sol.
[0062] Step 2), preparation of thiol-modified silver nanostar sol:
[0063] 0.35 g of NaCl was added to 20 ml of the solution containing AgNS sol, and the mixture was shaken and stirred for 30 min. g Centrifuge for 10 min under the same conditions, remove 19 mL of supernatant, and add 19 mL of deionized water. Centrifuge once under the same conditions, remove 19 mL of supernatant, and then add 19 mL of deionized water.
[0064] 20 mL of the chloride ion-substituted AgNS colloidal solution was added dropwise to 0.1 mM 4-ATP aqueous solution (1.8 mL) and stirred at 1100 rpm. The pH of the mixture was adjusted to 2.5 by adding 1 M HCl solution. g The mixture was centrifuged for 5 min under the same conditions, 19 mL of supernatant was removed, and 19 mL of deionized water was added to prepare a thiol-modified silver nanostar sol solution.
[0065] Step 3), preparation of paper-based silver nanostars:
[0066] The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) with a vacuum filtration bottle at a vacuum degree of 0.7 MPa for 3 min.
[0067] Step 4), hydrophobization of polydimethylsiloxane (PDMS):
[0068] PDMS (1.2 g) was dissolved in 25 mL of n-hexane and stirred for 4 h to prepare a hydrophobic solution. The resulting paper-based silver nanostars were immersed in the hydrophobic solution for 10 min and then dried at 70 °C for 3 h to obtain the following: Figure 3 The hydrophobized thiol-modified silver nanostar paper-based material shown can be used as a substrate for SERS detection.
[0069] Example 3
[0070] Step 1), preparation of silver nanostar (Ag NS) sol at room temperature:
[0071] Mix 5 mL of hydroxylamine aqueous solution (H3NO, 0.06 M) and 5 mL of NaOH aqueous solution (0.05 M) for 4 min. Then, pour 90 mL of 1 mM AgNO3 aqueous solution into the above mixed solution at once while stirring. After stirring for 5 min, add 1 mL of sodium citrate aqueous solution (1%, w / v , w is sodium citrate, v is deionized water), and shaken for 15 min to obtain a solution containing AgNS sol.
[0072] Step 2), preparation of thiol-modified silver nanostar sol:
[0073] 0.35 g of NaCl was added to 20 ml of the solution containing AgNS sol, and the mixture was shaken and stirred for 30 min. g Centrifuge for 10 min under the same conditions, remove 19 mL of supernatant, and add 19 mL of deionized water. Centrifuge once under the same conditions, remove 19 mL of supernatant, and then add 19 mL of deionized water.
[0074] 20 mL of the chloride ion-substituted AgNS colloidal solution was added dropwise to 0.1 mM 4-ATP aqueous solution (2 mL) and stirred at 1100 rpm. The pH of the mixture was adjusted to 2 by adding 1 M HCl solution. g The mixture was centrifuged for 5 min under the same conditions, 19 mL of supernatant was removed, and 19 mL of deionized water was added to prepare a thiol-modified silver nanostar sol solution.
[0075] Step 3), preparation of paper-based silver nanostars:
[0076] The thiolated silver nanostar sol solution obtained in step 2) was vacuum filtered using a cellulose circular filter paper (5 cm in diameter) with a vacuum filtration bottle at a vacuum degree of 0.8 MPa for 3 min.
[0077] Step 4), hydrophobization of polydimethylsiloxane (PDMS):
[0078] PDMS (1.3 g) was dissolved in 25 mL of n-hexane and stirred for 4 h to prepare a hydrophobic solution. The resulting paper-based silver nanostars were immersed in the hydrophobic solution for 12 min and then dried at 70 °C for 3.5 h to obtain the following: Figure 3The hydrophobized thiol-modified silver nanostar paper-based material shown can be used as a substrate for SERS detection.
[0079] When used, the hydrophobized thiol-modified silver nanostar paper-based material of the present invention can be used to quickly screen perchlorate in water (actual water samples) based on surface enhanced Raman scattering (SERS).
[0080] Actual sample analysis
[0081] Prepare seven replicates of 100 μM ClO4 in deionized water - The mother solution was then diluted to 80, 50, 20, 10, 5, and 1 μM in six portions. The above Raman parameters were used for SERS detection. - The concentration is the horizontal axis, Figure 1 ClO4 - The SERS response intensity (937 cm -1 ) is the vertical coordinate, and the Figure 2 The standard curve shown (R 2 =0.9917).
[0082] The limit of detection (LOD) was calculated as 3.3δ / S, where δ is the standard deviation of the blank sample (n=6) and S is the slope of the linear curve. The LOD was 0.015 μM (1.83 μg / L). SERS analysis of water samples from the Bahe and Weihe rivers (n=30) near Xi'an, Shaanxi Province, revealed the presence of perchlorate in all samples, but after concentration conversion, the concentrations were all below 20 μg / L.
Claims
1. A method for preparing a hydrophobized thiol-modified silver nanostar paper-based material, characterized in that: The steps include: S1, first using NaCl to replace the citrate modified on the surface of the silver nanostar sol, and then removing excess chloride ions, specifically, adding NaCl to the silver nanostar sol solution, the molar ratio of NaCl to silver ions in the silver nanostar sol solution is 30:1, after centrifugation and washing, removing the supernatant, and then adding deionized water for centrifugation and washing to obtain the replaced silver nanostar sol; S2, using 4-aminothiophenol to perform thiol modification on the replaced silver nanostar sol, specifically, adding the replaced silver nanostar sol solution to a 4-aminothiophenol aqueous solution while stirring to obtain a mixed solution, then adjusting the pH of the mixed solution to 1.5-2.5 with a 1 M HCl solution, centrifuging to remove the supernatant, and then adding deionized water with the same volume as the supernatant, wherein the molar ratio of silver ions in the replaced silver nanostar sol solution to 4-aminothiophenol in the 4-aminothiophenol aqueous solution is 200:(1.3-2), thereby obtaining a thiol-modified silver nanostar sol solution; S3, vacuum filtering the thiol-modified silver nanostar sol solution on filter paper by vacuum filtration, so that the thiol-modified silver nanostar sol is loaded on the filter paper to obtain a paper-based substrate, and then the paper-based substrate is hydrophobized using polydimethylsiloxane to obtain a hydrophobized thiol-modified silver nanostar paper-based material.
2. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 1, wherein: S3: The vacuum degree when the thiol-modified silver nanostar sol is loaded on the filter paper is 0.6-0.8 MPa, and the vacuum filtration is carried out for 2-4 minutes.
3. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 1, wherein: S3 first dissolves 1.1-1.3 g of PDMS in 25-35 mL of n-hexane to obtain a hydrophobic solution, and then immerses the paper-based substrate in the hydrophobic solution for 8-12 min to obtain a hydrophobized thiol-modified silver nanostar paper-based material.
4. The method for preparing the hydrophobized thiol-modified silver nanostar paper-based material according to claim 3, wherein: S3: immersing the paper-based substrate in a hydrophobic solution for 8-12 minutes, taking it out, and drying it at 60-80° C. for 2.5-3.5 hours to obtain a hydrophobized thiol-modified silver nanostar paper-based material.
5. A hydrophobized thiol-modified silver nanostar paper-based material obtained by the preparation method of the hydrophobized thiol-modified silver nanostar paper-based material according to any one of claims 1 to 4.
6. Use of the hydrophobized thiol-modified silver nanostar paper-based material according to claim 5 in rapid screening of perchlorate in water.