A fluorescence probe based on a supramolecular assembly of gold nanoclusters and its application in the detection of perfluorooctanesulfonic acid

Abstract

A fluorescence probe based on a supramolecular assembly of gold nanoclusters and its application in the detection of perfluorooctane sulfonic acid, belonging to the technical field of fluorescence detection. In the present invention, HAuCl4·3H2O is used as the Au source, cytidine-5'-phosphate is used as the stabilizer, and citric acid is used as the reducing agent to prepare gold nanoclusters. Then, the assembly formed by the gold nanoclusters and CLD215 is used as the fluorescence probe. Perfluorooctane sulfonic acid causes the dissociation of the assembly through competitive action, thereby generating a fluorescence quenching response. A linear curve of fluorescence intensity-PFOS concentration of the fluorescence emission spectrum of AuNCs / CLD215 is established, so as to realize the highly sensitive quantitative detection of the pollutant perfluorooctane sulfonic acid (PFOS), with high sensitivity and a wide detection range. In addition, this fluorescence probe has successfully detected PFOS in mineral water and soil water in kind and obtained a high recovery rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescence detection, and particularly relates to a fluorescence probe based on a supramolecular assembly of gold nanoclusters and its application in the detection of perfluorooctane sulfonic acid. Background Art

[0002] Perfluorinated compounds are synthetic fluorinated organic compounds that have been widely used in surfactants, stain protection products, adhesives, fire-fighting foams, pesticides, and food packaging due to their unique hydrophobic and lipophobic properties. Since perfluorinated compounds have very strong C-F bonds (485 kJ·mol -1 ), they have very high thermal and chemical stability. Additionally, due to their toxicity and bioaccumulation, they are classified as persistent organic pollutants.

[0003] In recent years, numerous reports have evaluated the toxicity of perfluorinated compounds and their health risks to animals and humans. They can cause adverse damage to the kidneys, liver, and immune system by binding to proteins. Due to the thermal and chemical stability of the high-energy carbon-fluorine bond, perfluorinated compounds have high environmental persistence. At the same time, it can be transferred, bioaccumulated, and biomagnified along the food chain. Perfluorooctane sulfonic acid (PFOS), which has both a long chain (the number of carbon atoms containing fluorine bonds ≥ 8) and a sulfonic acid group, is more likely to accumulate and magnify in organisms. Therefore, among a large number of perfluorinated compounds, perfluorooctane sulfonate (PFOS) is the most representative persistent organic pollutant. Currently, its presence has been detected in the oceans and rivers around the world, in the sera of many animals, and in occupationally exposed workers and the general public. This indicates that these perfluorinated compounds are globally distributed, so it is of great significance to monitor PFOS in the environmental system.

[0004] Currently, common PFOS quantitative detection methods include: high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS / MS), gas chromatography-mass spectrometry (GC / MS), surface-enhanced Raman scattering (SERS), resonance light scattering, electrochemistry analysis, etc. Although these methods have certain advantages, they still have disadvantages such as complex synthesis processes, complex sample preparation, expensive instrument requirements, and time-consuming procedures, which hinder their application in the high-throughput monitoring of environmental samples. Fluorescent sensors have received increasing attention due to their high sensitivity, convenient operation, and non-destructive detection methods. However, fluorescent probes for PFOS detection are still very rare, for example, upconversion nanoparticles, quantum dots, and organic conjugated materials. But many materials are restricted in application due to poor water solubility, high price, and poor selectivity. Therefore, developing a simple, rapid, cost-effective PFOS determination method remains a challenge.

[0005] On the other hand, metal nanoclusters have a unique core-shell structure and discrete energy levels, enabling AuNCs to exhibit full-spectrum photoluminescence from blue to near-infrared. In addition, they possess excellent photostability, long carrier lifetime, Stokes shift, low toxicity, and good biocompatibility, showing excellent performance in analysis, sensing, and bioimaging. However, the luminescence of gold nanoclusters is generally weak, which severely limits their applicability in luminescence detection. In view of this, several strategies have been adopted, such as doping metal ions (Ag and Cu), host-guest assembly and embedding in polymer matrices, and aggregation-induced emission enhancement, to improve the luminescence performance. Aggregation-induced emission enhancement (AIEE) mainly refers to the reduction of intermolecular interactions through molecular packing, while significantly restricting intramolecular rotation in the aggregated state, thereby strongly suppressing the non-radiative inactivation process of single molecules. Eventually, the fluorescence intensity of AIEE (aggregation-induced emission enhancement) compounds in the solid state or aggregated state is much greater than that in dilute solutions. Therefore, in this experiment, through the supramolecular assembly of amino-functionalized calix[4]arene, the metal nanoclusters are aggregated to significantly enhance the luminescence intensity of the metal nanoclusters. Summary of the Invention

[0006] The object of the present invention is to provide a fluorescence probe based on a supramolecular assembly of gold nanoclusters and its application in the detection of perfluorooctanesulfonic acid.

[0007] In the present invention, through supramolecular assembly, the fluorescence of gold nanoclusters is enhanced and applied to the detection of PFOS in an aqueous medium. The gold nanoclusters are synthesized by a hydrothermal method using cytidine-5'-phosphate (5'CMP) as a ligand, with an excitation wavelength of 370 - 380 nm and the strongest emission wavelength of 570 - 590 nm. The luminescence performance of these gold nanoclusters is poor and their stability is low. Therefore, through supramolecular assembly with amino-functionalized calix[4]arene (CLD215), the fluorescence emission intensity of the gold nanoclusters is significantly increased. This fluorescence enhancement is attributed to the supramolecular assembly of CLD215 with the gold nanoclusters, effectively increasing the radiative transition rate while suppressing the non-radiative rate, thereby enhancing the luminescence intensity of the metal nanoclusters. In the present invention, the assembly formed by gold nanoclusters and CLD215 is used as a fluorescence probe. Perfluorooctanesulfonic acid causes the dissociation of the assembly through competitive interaction, thereby producing a fluorescence quenching response. A linear curve of fluorescence intensity - PFOS concentration of the AuNCs / CLD215 fluorescence emission spectrum is established, thus realizing the highly sensitive quantitative detection of the pollutant perfluorooctanesulfonic acid (PFOS). The results show that the linear range for detecting PFOS is 0 - 100 μM, and the detection limit is 5.1 μM, with high sensitivity and a wide detection range. In addition, this fluorescence probe has successfully detected PFOS in mineral water and soil water samples and obtained high recovery rates.

[0008] A fluorescence probe based on a supramolecular assembly of gold nanoclusters according to the present invention uses HAuCl4·3H2O as the Au source, cytidine-5'-phosphate (5'CMP) as the stabilizer, and citric acid as the reducing agent. First, HAuCl4·3H2O, cytidine-5'-phosphate, and a citric acid-sodium citrate buffer solution with pH = 4.5 are successively added to ultrapure water to form a mixed solution. In the mixed solution, the final concentration of HAuCl4·3H2O is 8 - 15 μM, the final concentration of cytidine 5'-monophosphate is 25 - 35 μM, and the final concentration of sodium citrate is 200 - 300 μM. Then, the obtained mixed solution is subjected to a hydrothermal reaction at 95 - 105 °C for 15 - 30 min to obtain a nucleotide-protected gold nanocluster solution. After centrifugation and freeze-drying into a solid powder, it is configured into an AuNCs solution with a MES-NaOH buffer solution. Then, amino-functionalized calix[4]arene (CLD215) is added to the AuNCs solution for supramolecular assembly, and thus a fluorescence probe solution based on a supramolecular assembly of gold nanoclusters is obtained through non-covalent bonds, namely electrostatic interaction. In the AuNCs solution, the ratio range of the concentration of AuNCs to the final concentration of calix[4]arene is 0.1 mg / mL:16 - 24 μM. Description of the Drawings

[0009] Figure 1 : (a) Fluorescence excitation spectrum (left curve) and fluorescence emission spectrum (right curve) of AuNCs in aqueous solution, (b) Transmission electron microscope (HR-TEM) image of AuNCs and grain size distribution diagram (inset); corresponding to Example 1;

[0010] Figure 2 : (a) Fluorescence emission spectra of AuNCs at different CLD215 concentrations, (b) Dot plot of the fluorescence intensity of the highest emission peak in the AuNCs fluorescence emission spectrum varying with the CLD215 concentration; corresponding to Example 2;

[0011] Figure 3 : (a) Transmission electron microscope (HR-TEM) image of AuNCs / CLD215 and grain size distribution diagram (inset) (b) UV absorption spectra of AuNCs at different CLD215 concentrations; corresponding to Example 3;

[0012] Figure 4 : (a) Fluorescence emission spectra of AuNCs at different PFOS concentrations, (b) Dot plot of the fluorescence intensity at 510 nm in the AuNCs fluorescence emission spectrum varying with the PFOS concentration; corresponding to Example 4;

[0013] Figure 5 : Fluorescence emission spectra of AuNCs / CLD215 at different PFOS concentrations; corresponding to Example 4;

[0014] Figure 6 :(a) Plot of the fluorescence intensity at 510 nm in the fluorescence emission spectrum of AuNCs / CLD215 as a function of the concentration of PFOS (0 - 180 μM), (b) Linear curve of the fluorescence intensity at 510 nm - PFOS concentration (0 - 100 μM) in the fluorescence emission spectrum of AuNCs / CLD215; corresponding to Example 4;

[0015] Figure 7 :(a) High - resolution transmission electron microscopy (HR - TEM) of AuNCs / CLD215 + PFOS and the grain size distribution diagram (inset); (b) UV - absorption spectra of AuNCs / CLD215 at different PFOS concentrations; corresponding to Example 5;

[0016] Figure 8 : Bar chart of the selectivity (a) and anti - interference analysis (b) of the fluorescence response of AuNCs / CLD215 to PFOS; The fluorescence quenching intensity ratio refers to the ratio of the quenching difference (I0 - I) between the fluorescence intensity at 510 nm before adding PFOS (I0) and the fluorescence intensity at 510 nm after adding PFOS (I) to the fluorescence intensity at 510 nm before adding PFOS (I0), that is, (I0 - I) / I0; corresponding to Example 6;

[0017] By comparing with the literature [1] on the fluorescence emission position of AuNCs ( Figure 1 a)), it was preliminarily determined that AuNCs had been synthesized. Secondly, the morphology of the prepared AuNCs was characterized ( Figure 1 b)). After particle size statistical analysis, it was found that the average grain size was ~1.45 nm. Through fluorescence spectroscopy and electron microscopy characterization, it was proved that the nucleotide - protected gold nanoclusters had been successfully synthesized.

[0018] As Figure 2 shown in a and b, as different concentrations (0, 4, 8, 12, 16, 20, 24 μM) of calix[4]arene (CLD215) were gradually added to the AuNCs solution, the fluorescence intensity of AuNCs showed an obvious enhancement phenomenon, and the lifetime also had a slight increase (Table 1), the fluorescence was enhanced (by ~8 times), and there was a certain degree of blue - shift phenomenon (by ~60 nm).

[0019] After that, this process was characterized to a certain extent. As Figure 3 shown in a, the morphology of AuNCs / CLD215 was characterized. By statistically analyzing the particle sizes of about 200 particles, the final statistical result was 10.07 nm. Compared with AuNCs, the particle size of the assembly increased. Therefore, it was shown that CLD215 and AuNCs underwent supramolecular assembly through electrostatic interaction, and the aggregation induced an enhancement in fluorescence emission.

[0020] AsFigure 4 As shown in a and b, with the gradual addition of PFOS at different concentrations (0, 20, 40, 80, 120, 200, 400 μM) to the AuNCs solution, there is no obvious quenching phenomenon in the fluorescence intensity, indicating that PFOS does not quench the fluorescence of the gold nanoclusters themselves. However, with the gradual addition of PFOS at different concentrations (0 - 180 μM) to the AuNCs / CLD215 solution, an obvious quenching phenomenon occurs in the fluorescence intensity ( Figure 5 ), indicating that PFOS can quench the fluorescence of the assembly of gold nanoclusters and calixarene. From Figure 6 It can be seen from b that AuNCs show a good linear response to PFOS in a very wide range from 0 to 100 μM. As the concentration of PFOS increases, the fluorescence intensity of the fluorescence probe at 510 nm decreases accordingly, and finally reaches a plateau at 180 μM ( Figure 6 a). The linear relationship between the fluorescence intensity I at 510 nm and the concentration of PFOS is as shown in Figure 6 b. The linear response to PFOS varies between 0 - 100 μM (R 2 = 0.995). And the AuNCs / CLD215 was diluted with 20 μM MES-NaOH buffer solution (pH 6.5), and the detection limit for PFOS was calculated to be 5.1 μM.

[0021] In addition, the effects of other interfering substances such as PFOA, CTAB, n-octanoic acid, sodium 1-octanesulfonate, Na2SO4, KCl, MgCl2, and NaCl on AuNCs / CLD215 were also analyzed. The results show that except for PFOS, other interfering substances do not cause obvious changes in the fluorescence intensity of AuNCs / CLD215, Figure 8 (a) shows that only PFOS can significantly quench the fluorescence of AuNCs / CLD215. Figure 8 (b) shows that the addition of other interfering substances to the solution containing PFOS does not affect the fluorescence response of AuNCs / CLD215 to PFOS. Therefore, we believe that these interfering substances have no effect on the detection of PFOS by the fluorescent AuNCs / CLD215 probe, indicating that this method is an effective means for detecting PFOS in practical applications. Detailed implementation mode

[0022] The cytidine 5'-monophosphate (CMP) used in the present invention was purchased from the product of TCI (Shanghai) Development Co., Ltd. Chloroauric acid trihydrate (HAuCl4·3H2O), sodium citrate, and citric acid were all purchased from Beijing Chemical Factory. Tetraethylammonium perfluorooctanesulfonate (PFOS), sodium 1-octanesulfonate, and morpholineethanesulfonic acid monohydrate (MES) were purchased from Shanghai Aladdin Reagent Co., Ltd. Sodium perfluorooctanoate (PFOA), n-octanoic acid, and cetyltrimethylammonium bromide (CTAB) were purchased from Shanghai Macklin Biochemical Co., Ltd. Basic chemicals such as sodium hydroxide (NaOH) were all purchased from Tianjin Guangfu Reagent Co., Ltd. All chemical reagents were of analytical grade and were not further purified. Ultra-pure water was used throughout the experiment.

[0023] Example 1:

[0024] According to the literature report [1] , successively add HAuCl4·3H2O, cytidine 5'-monophosphate (CMP), and citric acid-sodium citrate solution (pH = 4.5) to 7 mL of ultra-pure water. The final concentration of HAuCl4·3H2O is 10 μM, the final concentration of cytidine 5'-monophosphate is 30 μM, and the final concentration of sodium citrate is 250 μM; then, put the obtained mixture solution into a 20 mL high-pressure reactor and carry out hydrothermal reaction at 100 °C for 20 min. After cooling, a nucleotide-protected gold nanocluster solution (AuNCs) is obtained.

[0025] The results show that: The excitation wavelength of the AuNCs obtained based on Example 1 is 370 - 380 nm, and the emission wavelength is 570 - 590 nm ( Figure 1 a), and it is preliminarily determined that the gold nanoclusters are successfully synthesized through the emission position of the fluorescence spectrum. Secondly, the morphology of the prepared AuNCs is characterized ( Figure 1 b). It can be seen from the figure that the dispersion of the nanoparticles is relatively high and the particle size is relatively uniform. After statistically analyzing the particle sizes of about 200 AuNCs, it is found that the average grain size is ~1.45 nm, and the interplanar spacing of the crystal grains of AuNCs ( Figure 1 inset in b) is ~0.24 nm.

[0026] Example 2:

[0027] Centrifuge the AuNCs obtained in Example 1 by the acetone precipitation method. After centrifugation, freeze-dry the AuNCs into a solid powder and prepare a 1 mg / mL AuNCs mother liquor with MES-NaOH solution; then dilute it ten times with MES-NaOH buffer solution to obtain a 0.1 mg / mL AuNCs solution. Take 7 portions of 500 μL of 0.1 mg / mL AuNCs solution and add different amounts of CLD215 to them respectively, so that the final concentrations of CLD215 are 0, 4, 8, 12, 16, 20, and 24 μM (Figure 2 The results show that when the final concentration of calix[4]arene is 20 μM, the fluorescence intensity of gold nanoclusters increases to the strongest (it can be seen that when the concentration of AuNCs in the AuNCs solution is 0.1 mg / mL, the more appropriate final concentration of calix[4]arene is 16 - 24 μM), thus obtaining the fluorescence-enhanced assembly AuNCs / CLD215 (0.1 mg / mL, 20 μM), that is, a fluorescence probe based on the supramolecular assembly of gold nanoclusters.

[0028] When CLD215 reaches 20 μM, the fluorescence enhancement almost reaches a plateau ( Figure 2 , and the lifetime has a slight enhancement (Table 1), the fluorescence enhancement is about 8 times, and there is a certain degree of blue shift phenomenon (about 50 nm).

[0029] Table 1: Fluorescence lifetime measurement data of AuNCs and AuNCs / CLD215

[0030]

[0031] Example 3:

[0032] A series of characterizations were carried out on the fluorescence-enhanced assembly AuNCs / CLD215 (0.1 mg / mL, 20 μM) obtained in Example 2 to prove the binding mode between AuNCs and CLD215 and the mechanism of fluorescence enhancement. As Figure 3 shown in a, the morphology of AuNCs / CLD215 was characterized, and the particle size statistical result was 10.07 nm. Therefore, from AuNCs to AuNCs / CLD215 (20 μM) is a process of particle size growth, indicating that the reason for fluorescence enhancement is the enhancement of aggregation-induced emission.

[0033] In addition, the change in the ultraviolet absorbance of calix[4]arene (CLD215) with different concentrations (0, 4, 8, 12, 16, 20, 24 μM) gradually added to the AuNCs solution was monitored (3b), and it was found that there was a certain degree of enhancement, which also indicated that supramolecular assembly occurred between gold nanoclusters and calixarene, forming luminescent aggregates.

[0034] The results show that AuNCs and CLD215 underwent supramolecular assembly through electrostatic interaction, with an increase in particle size and the formation of luminescent aggregates.

[0035] Example 4:

[0036] The fluorescence-enhanced assembly AuNCs / CLD215 (0.1 mg / mL, 20 μM) obtained in Example 2 was used as a fluorescence probe for detecting PFOS. First, the experimental feasibility was tested, as Figure 4As shown in a and b, with the gradual addition of PFOS at different concentrations (0, 20, 40, 80, 120, 200, 400 μM) to the AuNCs solution, there was no obvious quenching of the fluorescence intensity ( Figure 4 a, b). The AuNCs / CLD215 (0.1 mg / mL, 20 μM) obtained in Example 2 was diluted two-fold with MES-NaOH buffer solution (at this time, the concentration of AuNCs in AuNCs / CLD215 was 50 μg / mL, and the concentration of CLD215 was 10 μM. According to the results of Example 2 and Example 4, when the concentration of AuNCs in the AuNCs solution was 50 μg / mL, the final concentration of the appropriate calix[4]arene was 8 - 12 μM). Take 500 μL of AuNCs / CLD215 (50 μg / mL, 10 μM) solution, and gradually add PFOS at different concentrations (0 - 180 μM, all concentrations in the present invention are final concentrations) to it, and there was an obvious quenching of the fluorescence intensity ( Figure 5 ). It indicates that PFOS does not quench the gold nanoclusters themselves, but has a quenching effect on the assembly, and thus AuNCs / CLD215 (50 μg / mL, 10 μM) was used to detect PFOS.

[0037] The present invention mainly focuses on the detection of PFOS. As can be seen from Figure 6 b, the AuNCs / CLD215 fluorescence probe shows a good linear response to PFOS in a very wide concentration range from 0 to 100 μM. As the concentration of PFOS increases, the fluorescence intensity of the fluorescence probe at 510 nm decreases accordingly, and finally reaches a plateau at 180 μM (6a). The linear relationship between the fluorescence intensity at 510 nm and the PFOS concentration is as shown in Figure 6 b. The linear response range for PFOS is 0 - 100 μM (Y = 3.01X + 447.256, R 2 = 0.995, where Y is the fluorescence intensity at 510 nm and X is the PFOS concentration). And after diluting AuNCs / CLD215 with 20 μM MES-NaOH buffer solution (pH 6.5), the detection limit of AuNCs / CLD215 for PFOS was calculated to be [2] 5.1 μM. The results show that AuNCs / CLD215 has a wide detection range and a good detection limit for detecting PFOS, and can be used as a fluorescence probe for detecting PFOS.

[0038] Example 5:

[0039] Characterize the process of detecting PFOS by AuNCs / CLD215 in Example 4. First, characterize the morphology of AuNCs / CLD215-PFOS ( Figure 7a). It can be seen from the figure that the nanoparticles have a high degree of dispersion and relatively uniform particle sizes. After statistically analyzing the particle sizes of approximately 200 grains, it is found that the average grain size is ~6.45 nm. By comparing with the particle size of AuNCs / CLD215 (10.07 nm), it can be found that the process from the assembly to the addition of PFOS is a depolymerization process. In addition, from the analysis of the ultraviolet absorption spectrum ( Figure 7 b), it is also found that, contrary to the upward trend of the ultraviolet absorption degree during the formation of the assembly, the ultraviolet absorption degree of AuNCs / CLD215 gradually decreases with the increase of the PFOS concentration after adding PFOS, which also proves that it is a depolymerization process and is consistent with the electron microscopy results. It can be found from Table 2 that there is almost no change in the fluorescence lifetime of AuNCs / CLD215 compared with that of AuNCs / CLD215-PFOS, indicating that the fluorescence quenching mechanism of AuNCs / CLD215-PFOS is static quenching.

[0040] Table 2: Fluorescence lifetime measurement data of AuNCs / CLD215 and AuNCs / CLD215 + PFOS

[0041]

[0042] Example 6:

[0043] To study the selectivity of AuNCs / CLD215 to PFOS, a certain amount (200 μM) of PFOS, PFOA, CTAB, n-octanoic acid, sodium octane sulfonate, Na2SO4, KCl, MgCl2, and NaCl were added to the AuNCs / CLD215 solution diluted with MES-NaOH buffer solution (pH 6.5), and quickly mixed. All fluorescence tests were carried out at room temperature. The results showed that PFOS quenched the fluorescence of AuNCs / CLD215 to the greatest extent, and the fluorescence of other assemblies was hardly quenched or only slightly quenched. This indicates that the AuNCs / CLD215 fluorescent probe can effectively detect PFOS ( Figure 8 a)

[0044] The method for the interference test was to add PFOS (200 μM) to the AuNCs / CLD215 solution diluted with MES-NaOH buffer solution (pH 6.5) and incubate for five minutes, and then add a series of interferents (200 μM) (CTAB, n-octanoic acid, sodium octane sulfonate, Na2SO4, KCl, MgCl2, NaCl) respectively, and then perform fluorescence spectrum tests. The results showed that adding other interferents to the solution containing PFOS would not affect the fluorescence response of AuNCs / CLD215 to PFOS. Figure 8 b).

[0045] Example 7:

[0046] For the detection of mineral water samples, 100 μL of mineral water was added to the AuNCs / CLD215 solution with the same concentration, and then three different final concentrations of PFOS (66 μM, 83 μM, 100 μM) were added to the above solution (denoted as 1# - 3#) respectively. After incubation for 2 min, fluorescence spectroscopy was performed. The results showed that the recovery rates were between 97.5% and 104.1%, and the relative standard deviations (RSDs) were all less than 5%, indicating that AuNCs / CLD215 could be applied in the detection of actual samples (Table 3).

[0047] Table 3: Measurement data of PFOS in mineral water

[0048]

[0049]

[0050] The detection method for soil water samples is as follows. First, according to the literature [3] with slight modification, the soil was treated. The soil (0.1 g, obtained from the shore of Yanhu Lake, Jilin University) was dispersed in 100 mL of MES-NaOH buffer solution (20 mM, pH = 6.5), and ultrasonic extraction was carried out (10 min); then the sample was heated to boiling, cooled to room temperature, and centrifuged (8000 rpm, 10 min); finally, it was filtered through a 0.22 μm filter membrane and measured under the same conditions. The results showed that the recovery rates were between 95.6% and 104.8%, and the relative standard deviations (RSDs) were all less than 5%, indicating that AuNCs / CLD215 could be applied in the detection of actual samples (Table 4).

[0051] Table 4: Measurement data of PFOS in soil water samples

[0052]

[0053] It should also be noted that the specific embodiments of the present invention are only used for exemplary illustration and do not limit the protection scope of the present invention in any way. Those skilled in the relevant art can make improvements or changes according to the above descriptions, but all such improvements and changes should fall within the protection scope of the claims of the present invention.

[0054] References

[0055] [1] Zhang Chunxia, Wang Yu, Wu Yuqing, Li Hongwei, etc.; Development of cytidine 5'-monophosphate protected gold nanoclusters with enhanced aggregation-induced emission as a direct luminescent substrate for the ratio determination and inhibitor evaluation of alkaline phosphatase [J], Colloids and Surfaces A: Physicochemical and Engineering Aspects, 640 (2022), 128423;

[0056] [2] Zheng Zhe, Geng Wenchao, Gao Jie, Mou Yijiang, Guo Dongsheng; Pattern of Differentiating Glycosaminoglycans by Different Aryl Hydrocarbon Receptors [J], Organic Chemistry Frontiers, 2018, 5, 2685-2691;

[0057] [3] Zhang Qiaojuan, Liao Mengyu, Yao Yizhi, et al.; A Water-Soluble Fluorescent Probe Based on Peralkynedicarboximide for Perfluorooctane Sulfonate in 100% Aqueous Medium [J], Sensors and Actuators: B. Chemical, 350 (2022) 130851.

Claims

1. A fluorescence probe based on a supramolecular assembly of gold nanoclusters, characterized in that: HAuCl4∙3H2O was used as the Au source, cytidine-5'-phosphate as the stabilizer, and citric acid as the reducing agent. First, HAuCl4∙3H2O, cytidine-5'-phosphate, and a citric acid-sodium citrate buffer solution with pH = 4.5 were successively added to ultrapure water to form a mixed solution. In the mixed solution, the final concentration of HAuCl4∙3H2O was 8 - 15 μM, the final concentration of cytidine 5'-monophosphate was 25 - 35 μM, and the final concentration of sodium citrate was 200 - 300 μM. Then, the obtained mixed solution was subjected to a hydrothermal reaction at 95 - 105 °C for 15 - 30 min to obtain a nucleotide-protected gold nanocluster solution. After centrifugation and freeze-drying into a solid powder, it was configured into an AuNCs solution with a MES-NaOH buffer solution. Then, amino-functionalized calix[4]arene was added to the AuNCs solution for supramolecular assembly, so as to obtain a fluorescent probe solution based on a gold nanocluster supramolecular assembly through non-covalent bonds, namely electrostatic interaction. In the AuNCs solution, the ratio range of the concentration of AuNCs to the final concentration of calix[4]arene was 0.1 mg / mL: 16 - 24 μM.

2. Application of a fluorescent probe based on a gold nanocluster supramolecular assembly according to claim 1 in the detection of perfluorooctanesulfonic acid.

3. Use of a fluorescence probe based on a gold nanocluster supramolecular assembly as described in claim 2 in the detection of perfluorooctane sulfonic acid, characterized in that: When the concentration of AuNCs in the AuNCs solution was 0.05 mg / mL and the final concentration of calix[4]arene was 10 μM, the linear response range of the fluorescent probe to the concentration of perfluorooctanesulfonic acid was 0 - 100 μM, and the detection limit was 5.1 μM.

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