A fluorescent probe for detecting perfluorooctane sulfonic acid, and a preparation method and application thereof

Abstract

The application discloses a fluorescent probe for detecting perfluorooctane sulfonic acid, and a preparation method and application thereof, and belongs to the technical field of analysis and detection. The structure of the fluorescent probe is as follows: the fluorescent probe has high specific recognition and high sensitivity response for perfluorooctane sulfonic acid, can realize fluorescence opening after specific recognition with perfluorooctane sulfonic acid, and has a color difference that can be observed by naked eyes. The preparation method of the fluorescent probe is simple, the conditions are mild, the cost is low, the effect is remarkable, and the fluorescent probe can be applied to an actual sample quality inspection system.

Description

Technical Field

[0001] This invention relates to a fluorescent probe, specifically an organic small molecule fluorescent probe constructed from triphenylamine, benzothiazole and pyridine, and also to its preparation method and application in the fluorescence detection of PFOS, belonging to the field of environmental detection technology. Background Technology

[0002] Perfluorooctane sulfonic acid (PFOS), a typical representative of perfluorinated and polyfluoroalkyl substances (PFAS), is a synthetic compound with high chemical stability, high temperature resistance, and hydrophobic and oleophobic properties. Since the mid-20th century, it has been widely used in many industrial fields and daily consumer goods, including textiles, fire protection, electroplating, and food packaging. However, PFOS has extremely strong environmental persistence. Its carbon-fluorine bond energy is as high as 485 kJ / mol, making it difficult to decompose in the natural environment through conventional methods such as photodegradation and biodegradation. Therefore, it is called a "permanent chemical substance." With migration and diffusion during production, use, and disposal, PFOS has been widely detected in soil, water bodies, atmosphere, and even polar ice and snow worldwide, forming a comprehensive environmental pollution pattern. More alarmingly, PFOS has significant bioaccumulation and biomagnification effects. It can enter the human body through multiple routes such as drinking water, food, and respiration, accumulating in tissues such as blood, liver, and kidneys for a long time. Moreover, its concentration increases with the trophic level of the food chain.

[0003] Numerous toxicological studies and epidemiological surveys have confirmed that PFOS poses a serious threat to the ecological environment and human health. For aquatic organisms, even low-concentration PFOS exposure can lead to a series of adverse effects, such as decreased fish reproductive capacity, embryonic malformations, and immune dysfunction, disrupting the balance and stability of aquatic ecosystems. For humans, long-term exposure to PFOS is closely related to the occurrence and development of various diseases, including endocrine disorders, reproductive and developmental disorders, increased risk of cardiovascular disease, and may even induce malignant tumors such as liver and kidney cancer. It can also cause irreversible damage to children's intellectual and physical development. Given the high hazard of PFOS, its production, use, and emission are currently strictly controlled and strictly limited. Accurate, rapid, and sensitive detection of PFOS in environmental media and biological samples is the prerequisite and core for pollution source tracing, risk assessment, and control and remediation. Currently, PFOS detection methods mainly include instrumental analytical methods such as high-performance liquid chromatography-mass spectrometry (HPLC-MS / MS) and gas chromatography-mass spectrometry (GC-MS). These methods have advantages such as high detection sensitivity and accurate qualitative and quantitative analysis, but they also have limitations such as expensive equipment, complex operation procedures, cumbersome sample pretreatment, long detection cycle, and the need for professional technicians to operate them, making it difficult to meet the actual needs of rapid on-site detection, large-scale screening, and real-time monitoring. Summary of the Invention

[0004] In view of the shortcomings of existing technologies, the present invention aims to improve existing PFOS detection methods and obtain detection probes and corresponding detection methods with high sensitivity and portability.

[0005] To address the shortcomings of existing fluorescent probes for detecting PFOS, the first objective of this invention is to provide a fluorescent probe with excellent fluorescence properties, strong anti-interference ability, good stability, and the ability to accurately identify PFOS and emit a strong fluorescence signal. This probe enables the quantitative detection of PFOS and provides an effective molecular probe for the analysis and detection of residual perfluorinated substances in samples.

[0006] The second objective of this invention is to provide a method for preparing a fluorescent probe that is simple to operate, has a short process, and is under mild conditions, which is conducive to large-scale production.

[0007] The third objective of this invention is to provide an application of a fluorescent probe for detecting PFOS residues in a solution system. This fluorescent probe can specifically identify PFOS, and it forms a complex with PFOS. Under natural light, different concentrations of PFOS will show color changes visible to the naked eye, while under ultraviolet light, different concentrations of PFOS will exhibit a strong red fluorescence phenomenon. Both methods can achieve qualitative or quantitative analysis of PFOS, greatly facilitating the observation of perfluorinated residues.

[0008] To achieve the above technical objectives, the present invention provides a fluorescent probe having the structure of Formula 1:

[0009]

[0010] Formula 1.

[0011] The fluorescent probe of this invention possesses a unique molecular structure. It utilizes triphenylamine, a photosensitive precursor known for its photostability, strong conjugation, high fluorescence quantum yield, and large Stokes shift, as the fluorescence output unit. Furthermore, benzothiazole and pyridine structural interactions are introduced onto the triphenylamine unit to construct an AIE-based on-hook fluorescence response. By adding multiple nitrogen ions to the triphenylamine unit, the overall water solubility of the fluorescent probe molecule is altered, facilitating its application in aqueous environments. The introduction of benzothiazole onto the triphenylamine unit expands the conjugated system, resulting in more efficient emission behavior through charge transfer within a larger donor-acceptor molecule. In dilute solutions, the probe of this invention undergoes rapid internal rotation, causing the excited-state energy to dissipate via non-radiative transitions, resulting in only weak fluorescence. When PFOS binds to the probe via electrostatic attraction, the molecular stacking effect restricts intramolecular rotation and movement in the aggregated state of the complex, effectively suppressing nonradiative transitions and promoting the release of excited state energy in the form of radiative transitions. At the same time, since the long chain of PFOS is hydrophobic, it forms hydrophobic micelles after binding with the probe. The hydrophobic effect can provide thermodynamic assistance for molecular aggregation, thereby enabling fluorescence to be turned on at 728 nm.

[0012] In the fluorescent probe (Formula 1) of this invention, the balancing anion is bromine.

[0013] This invention also provides a method for preparing a fluorescent probe, which includes the following steps:

[0014] Step 1: Triphenylamine 4-boronic acid and 4,7-dibromo-2,1,3-benzothiadiazole undergo a Suzuki coupling reaction to obtain intermediate 1;

[0015] Step 2: Intermediate 1 undergoes a Suzuki coupling reaction with pyridine-4-boronic acid to obtain intermediate 2;

[0016] Step 3: Intermediate 2 undergoes a substitution reaction with (3-bromopropyl)trimethylammonium bromide to obtain the final product;

[0017] in,

[0018] The structural formula of intermediate 1 is: ;

[0019] The structural formula of intermediate 2 is: .

[0020] As a preferred embodiment, in step one, the Suzuki coupling reaction is carried out under the following conditions: using K₂CO₃ and tetra(triphenylphosphine)palladium as catalysts, and tetrahydrofuran and water as solvents, under nitrogen protection, at a temperature of 65-75°C for 8-12 hours. K₂CO₃, as a basic catalyst, can activate the hydrogen atom of the benzene ring and neutralize the acidic substances produced in the reaction. The solvent consists of tetrahydrofuran and water in a volume ratio of 5-15:1. This preferred solvent system improves the solubility of the raw materials and increases the reaction efficiency. The preferred molar ratio of 4-boronic acid triphenylamine to 4,7-dibromo-2,1,3-benzothiadiazole is 1:1.

[0021] As a preferred embodiment, in step two, the Suzuki coupling reaction is carried out under the following conditions: using K₂CO₃ and tetra(triphenylphosphine)palladium as catalysts, and tetrahydrofuran and water as solvents, under nitrogen protection, at a temperature of 65-75°C for 8-12 hours. K₂CO₃, as a basic catalyst, can activate the hydrogen atom of the benzene ring and neutralize the acidic substances produced in the reaction. The solvent consists of tetrahydrofuran and water in a volume ratio of 5-15:1. This preferred solvent system improves the solubility of the raw materials and increases the reaction efficiency. The preferred molar ratio of pyridine-4-boronic acid to 4-(7-bromobenzo[C][1,2,5]thiadiazol-4-yl)-N,N-diphenylaniline is 1:1.

[0022] As a preferred embodiment, the substitution reaction is carried out under the following conditions: using acetonitrile as a solvent, under nitrogen protection, and at a temperature of 70-90°C for 10-12 hours. The molar ratio of intermediate 2 to (3-bromopropyl)trimethylammonium bromide during the substitution reaction is preferably 1:1.5-2. The reaction temperature is further preferably 80-85°C.

[0023] This invention also provides an application of a fluorescent probe for the fluorescence detection of PFOS. The fluorescent probe of this invention exhibits high selectivity and high sensitivity for PFOS, with significant changes in fluorescence signal, enabling quantitative detection of PFOS.

[0024] As a preferred embodiment, the probe should be used for the qualitative and quantitative detection of PFOS in complex solution systems containing Na. + K + Ca 2+ Zn 2+ Mg 2+ F - I - SO3 2- CO3 2- SO4 2- HCO3 - Cl - NO2- NO3 - The fluorescent probe of this invention contains at least one impurity selected from PFO, PFBA, FBSA, and PFOA. It exhibits selective recognition of PFOS with high specificity. Common ions, small molecules, and other perfluorinated substances do not affect the signal ratio of the fluorescent probe.

[0025] Compared with existing technologies, the beneficial technical effects of the present invention are as follows:

[0026] The fluorescent probe of this invention not only has stable and excellent fluorescence performance, but also can selectively identify PFOS, enabling quantitative detection of PFOS and providing an effective, portable, and visually observable fluorescent molecular probe for environmental pollution monitoring.

[0027] The fluorescent probe of this invention has good water solubility, which is beneficial for its dissolution and dispersion in aqueous solution, and can realize the detection of samples in aqueous solution.

[0028] The fluorescent probe of this invention can achieve quantitative detection of PFOS with high selectivity. Common ions and small molecules do not affect the fluorescence performance of the fluorescent probe or its selective recognition of PFOS.

[0029] The method for preparing the fluorescent probe of the present invention is simple to operate, has a short process, mild conditions, and low cost, which is conducive to large-scale production. Attached Figure Description

[0030] Figure 1 The synthesis route for the fluorescent probe TPA-NN is shown.

[0031] Figure 2 The image shows the UV absorption and fluorescence emission spectra of the fluorescent probe TPA-NN.

[0032] Figure 3 The photostability experiment of the fluorescent probe TPA-NN.

[0033] Figure 4 AIE effect spectral analysis of the fluorescent probe TPA-NN.

[0034] Figure 5 The fluorescence titration spectra of the fluorescent probes TPA-NN and PFOS were determined.

[0035] Figure 6 This is a bar chart showing the relative fluorescence ratios for the selectivity test of the fluorescent probe TPA-NN.

[0036] Figure 7 This is a bar chart showing the relative fluorescence ratio of the fluorescent probe TPA-NN for the selectivity test of perfluorinated analogs.

[0037] Figure 8 The graph shows the linear analysis of RGB values ​​of the fluorescent probe TPA-NN for different concentrations of PFOS.

[0038] Figure 9 This is a table showing the data recovery analysis of spiked samples using the fluorescent probe TPA-NN. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, this should not be construed as limiting the scope of protection of the claims of the present invention. Any modifications or substitutions made to the methods, steps or conditions of the present invention without departing from the spirit and substance of the present invention shall fall within the scope of protection of the present invention.

[0040] In the following examples, experimental methods without specific conditions and reagents without formulations were all performed under conventional conditions in the art.

[0041] Example 1

[0042] The preparation method and specific synthetic route of the fluorescent probe are as follows: Figure 1 As shown.

[0043] Synthesis of Intermediate 1: Under nitrogen protection, triphenylamine 4-borate (289.1 mg, 1 mmol), 4,7-dibromo-2,1,3-benzothiadiazole (293.9 mg, 1 mmol), potassium carbonate (552.8 mg, 4 mmol), and tetra(triphenylphosphine)palladium (23.1 mg, 0.02 mmol) were sequentially added to a round-bottom double-necked flask. Immediately afterwards, a mixture of 10 mL tetrahydrofuran and 1 mL water was added to the flask. After the addition was complete, the reaction system was stirred under reflux for 8 h. After the reaction was complete and cooled to room temperature, extraction was performed using dichloromethane. The extracted solution was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum evaporation to obtain the crude product. Separation was performed using silica gel column chromatography with petroleum ether:dichloromethane (PE:DCM = 10:1, v / v). The product was pale yellow, with a yield of 70%.

[0044] 1 H NMR (400 MHz, CDCl3): δ 7.90 (d, J = 7.6 Hz, 1H), 7.80 (d, J = 8.7 Hz, 2H), 7.54 (d, J = 7.6 Hz, 1H), 7.30 (t, J = 7.8 Hz, 4H), 7.19 (dd, J = 8.2, 2.9Hz, 6H), 7.08 (t, J = 7.3 Hz, 2H).

[0045] MS (TOF): [M]+ caLcd.459.2 found:459.1.

[0046] Synthesis of Intermediate 2: Under nitrogen protection, pyridine-4-boronic acid (122.9 mg, 1 mmol), 4-(7-bromobenzo[C][1,2,5]thiadiazol-4-yl)-N,N-diphenylaniline (459.2 mg, 1 mmol), potassium carbonate (552.8 mg, 4 mmol), and tetrakis(triphenylphosphine)palladium (23.1 mg, 0.02 mmol) were sequentially added to a round-bottom double-necked flask. Immediately afterwards, a mixture of 10 mL tetrahydrofuran and 1 mL water was added to the flask. After the addition was complete, the reaction system was stirred continuously under reflux for 8 h. After the reaction was completed and cooled to room temperature, extraction was performed using dichloromethane. The extracted solution was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum evaporation to obtain the crude product. Separation was performed using silica gel column chromatography with petroleum ether:dichloromethane (PE:DCM = 10:1, v / v) as the eluent. The product is orange in color, and the yield is 50%.

[0047] 1 H NMR (400 MHz, CDCl3): δ 8.78 (d, J = 6.0Hz, 2H), 7.95 (dd, J=4.6, 1.5Hz, 2H), 7.89 (dd, J=8.1, 1.6Hz, 3H), 7.79 (d, J=7.4 Hz, 1H), 7.31 (t, J =7.9 Hz, 4H), 7.21 (t, J=7.9 Hz, 6H), 7.09 (t, J=7.3Hz, 2H).

[0048] MS (TOF): [M] + caLcd.456.57 found:456.3.

[0049] Synthesis of probe TPA-NN: Under nitrogen protection, intermediate 2 (456.5 mg, 1 mmol) and (3-bromopropyl)trimethylammonium bromide (397.6 mg, 1.5 mmol) were placed in a round-bottom double-necked flask, followed by the addition of 10 mL of acetonitrile. The mixture was stirred under reflux for 12 h. After cooling to room temperature, the solvent was removed using a rotary evaporator to obtain the crude product. Separation was then performed using a silica gel column with dichloromethane and methanol as eluents (DCM:MeOH = 50:1, v / v). The product was deep purple, and the calculated yield was 30%.

[0050] 1H NMR (400 MHz, DMSO) δ 9.25 (d, J = 6.7 Hz, 2H), 8.95 (d, J = 6.9Hz, 2H), 8.51 (d, J = 7.6 Hz, 1H), 8.06 (dd, J = 20.7, 8.2 Hz, 3H), 7.36 (t,J = 7.8 Hz, 4H), 7.11 (dt, J = 13.6, 7.0 Hz, 8H), 4.71 (t, J = 7.3 Hz, 2H), 3.57 (s, 2H), 3.33-3.29 (m, 9H), 2.49 (s, 2H).

[0051] MS (TOF): [M] + caLcd.278.63 found:278.62.

[0052] Example 2

[0053] Determination of probe fluorescence spectroscopy:

[0054] Accurately weigh 5 mg of probe TPA-NN and dissolve it in 1 mL of DMSO to prepare a 10 mM stock solution. Heat and sonicate to completely dissolve the solution. Take 100 μL of the 10 mM stock solution and dilute it with DMSO to a final 1 mM stock solution. Aliquot the solution into 2 mL EP tubes and store at -20°C. PFOS solution preparation: Accurately weigh 5 mg of PFOS powder and dissolve it in 1 mL of MeOH to prepare a 10 mM stock solution. Take 100 μL of the 10 mM stock solution and dilute it with MeOH to a final 1 mM stock solution. Aliquot the solution into 2 mL EP tubes and store at -20°C. Use a pipette to transfer 10 μL of the 1 mM probe TPA-NN solution and dilute it in 1 mL of ultrapure water to prepare a 10 μM probe solution for detection. Add different concentrations of PFOS solution to ultrapure water containing 10 μM of probe molecule TPA-NN. UV absorption was measured using a UH-5300 UV-Vis spectrophotometer at a scan rate of 800 nm / min with a data interval of 1 nm. Fluorescence spectra were measured using an F-7000 fluorescence spectrophotometer with an excitation source of 510 nm (EX Slit: 10 nm, EM Slit: 10 nm). Figure 2 As shown in Figure a, the absorption peak at 728 nm decreased significantly after the addition of PFOS. Figure 2 As shown in Figure b, the fluorescence intensity of the probe was low before the addition of PFOS, but the fluorescence peak was significantly enhanced after the addition of PFOS, showing an off-on fluorescence change.

[0055] Example 3

[0056] Study on probe photostability:

[0057] To further investigate the photostability of the TPA-NN probe under prolonged excitation illumination, a prepared 10 μM probe solution was used as a control, while other groups were treated with different concentrations of PFOS solution. Fluorescence changes in these systems were detected at different time points (0, 10, 30, 40, 60, 90, 120, 150, 180, 240, 300 s). Figure 3 As shown, the fluorescence emission intensity ratio of the probe TPA-NN did not change significantly with the extension of illumination time, indicating that the probe has good photostability. Different concentrations of PFOS solutions reached a plateau response within 2 minutes. The fluorescence testing conditions were: λex = 510 nm, λem = 728 nm (EXSlit: 10 nm, EM Slit: 10 nm).

[0058] Example 4

[0059] AIE effect spectral testing of probe TPA-NN:

[0060] The AIE effect of the probe TPA-NN was further investigated. Changes in fluorescence intensity were detected after adding 10 μM of the probe to prepared organic solvents (DMSO, EtOH, MeCN) with different water fractions. Figure 4 As shown, TPA-NN exhibits low fluorescence intensity in pure organic solvents in the DMSO / H2O system, but the fluorescence intensity increases when the water content is greater than 50%. Figure 4 (a) In the EtOH / H2O system, the fluorescence intensity is weak when the water content is low, and the fluorescence intensity increases when the water content is greater than 50%. Figure 4 (b) In the MeCN / H2O system, the fluorescence intensity is weak when the water content is low, and gradually increases when the water content is greater than 70%. Figure 4 c). Fluorescence testing conditions were: λex = 510 nm, λem = 728 nm (EX Slit: 10 nm, EM Slit: 10 nm).

[0061] Example 5

[0062] Probe fluorescence titration spectroscopy test:

[0063] 10 μL of a 1 mM probe TPA-NN stock solution was added to ultrapure water to prepare a 1 mL probe solution with a concentration of 10 μM. The fluorescence spectrum changes of the probe in different concentrations of PFOS were then tested. Figure 5 As shown, the fluorescence emission intensity increased after the addition of PFOS ( Figure 5(a). Furthermore, the probe exhibits good linearity in the 0 to 1 μM range ( Figure 5 (b) Therefore, the probe can quantitatively detect PFOS. The linear fitting equation is as follows: Figure 5 As shown, the detection limit for PFOS was calculated to be 0.006 μM. The fluorescence test conditions were: λex = 510 nm, λem = 728 nm (EX Slit: 10 nm, EM Slit: 10 nm).

[0064] Example 6

[0065] Selectivity testing of probes:

[0066] Selectivity experiments are an important indicator for evaluating probes. Several common potential interfering bioanalytes (Na+) were selected. + K + Ca 2+ Zn 2+ Mg 2+ F - I - SO3 2- CO3 2- SO4 2- HCO3 - Cl - NO2 - NO3 - Interfering compounds were tested for PFOS, with a blank control group included. Four other common perfluoro and polyfluoroalkyl compounds—perfluorooctane (PFO), perfluorobutyric acid (PFBA), perfluorobutyric acid sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and PFOS—were also tested, with a blank control group included. The interfering compounds were added to 10 μM probe solutions, and fluorescence changes were detected. Figure 6 As shown, the first bar represents the blank control, containing only the probe. Other analytes were added in sections 2-14 (as described above), and PFOS (10 μM) was added in section 15. The concentrations of each interfering substance in the probe solution were as follows (Na... + 10 μM; K + 10 μM; Ca 2+ 10 μM; Zn 2+ 10 μM; Mg 2+ 10 μM; F - 10 μM; I - 10 μM; SO3 2- 10 μM; CO3 2- 10 μM; SO4 2- 10 μM; HCO3- 10 μM; Cl - 10 μM; NO2 - 10 μM; NO3 - : 10 μM;). For example Figure 7 As shown, the first bar represents the blank control, containing only the probe. Other analytes were added in bars 2-5, and PFOS (10 μM) was added in bar 6. The concentrations of each interfering agent in the probe solution were (PFO 10 μM, PFBA 10 μM, FBSA 10 μM, PFOA 10 μM). The test results show that the fluorescence emission intensity of the probe at 728 nm remained essentially unchanged after the addition of other analytes, indicating good probe selectivity. The fluorescence testing conditions were: λex = 510 nm, λem = 728 nm (EX Slit: 10 nm, EM Slit: 10 nm).

[0067] Example 7

[0068] Investigating the quantitative analysis capability of the probe TPA-NN for PFOS:

[0069] Visual inspection alone inevitably carries the risk of human error. Combining color information with smartphone data to convert it into RGB values ​​for analysis has proven to be an effective method. This not only improves the accuracy and reliability of the detection results but also makes the detection platform more portable. Figure 8 The image shows the results of RGB analysis of fluorescence images using a color recognition app on a smartphone. This was achieved after capturing a series of fluorescence images (…). Figure 8 Afterwards, a color recognition program is used to convert the corresponding color photos into RGB values. Then, the PFOS concentration is obtained by calculating the intensity ratio of the red and blue channels. Figure 8 As shown, the red-to-blue channel ratio (R / B) exhibits a good linear relationship with PFOS concentration. These results demonstrate that the combination of the small molecule fluorescent probe TPA-NN with a smartphone enables portable, visualized, and quantitative monitoring of PFOS.

[0070] Example 8

[0071] Applications of probes in real-world sample detection:

[0072] The practical application potential of the probe TPA-NN in PFOS detection was evaluated using a standard spiked recovery method, selecting waterproof coatings, waterproof clothing coatings, and food packaging coatings as research subjects. Waterproof coating samples were immersed in 50 ml MeOH and pretreated by centrifugation (7000 rpm, 5 min) to remove precipitates. The supernatant was transferred to a 0.22 μM microporous membrane for filtration to remove excess impurities and then stored at -20℃ for subsequent analysis. For waterproof clothing coatings and food packaging coatings, 1 g of solid particles were weighed and extracted by immersion in 50 ml MeOH. After filtration, the filtrate was centrifuged (7000 rpm, 5 min) to remove precipitates. The supernatant was transferred to a 0.22 μM microporous membrane for filtration to remove excess impurities and then stored at -20℃ for subsequent analysis. Ultrapure water containing 10 μM of the probe molecule TPA-NN was used as the test system, with 10 μL of pretreated sample added as a control. Figure 9 As shown, spiked samples were prepared by adding 900 μL of pretreated sample to 100 μL of 10 mM PFOS stock solution to prepare a 1 mM spiked sample. Different concentrations (1 μM, 3 μM, 5 μM) of spiked samples were added to the test system for testing. Finally, the spiked recovery value was calculated based on the titration linearity data. Figure 9 As shown, the recovery rate was 89.3%–99.4%, and the relative standard deviation (RSD) was between 0.45 and 2.29, all within the acceptable range. This confirms that the PFOS sensing strategy based on probe TPA-NN has accuracy in the results and is highly feasible in the analysis of actual samples, showing promising application prospects.

Claims

1. A fluorescent probe, characterized in that: It has the structure of Formula 1: ； Formula 1.

2. The method for preparing a fluorescent probe according to claim 1, characterized in that: Includes the following steps: Step 1: Triphenylamine 4-boronic acid and 4,7-dibromo-2,1,3-benzothiadiazole undergo a Suzuki coupling reaction to obtain intermediate 1; Step 2: Intermediate 1 undergoes a Suzuki coupling reaction with pyridine-4-boronic acid to obtain intermediate 2; Step 3: Intermediate 2 undergoes a substitution reaction with (3-bromopropyl)trimethylammonium bromide to obtain the final product; in, The structural formula of intermediate 1 is: ; The structural formula of intermediate 2 is: .

3. The method for preparing a fluorescent probe according to claim 2, characterized in that: In step one, the conditions for the Suzuki coupling reaction are as follows: using K2CO3 and tetra(triphenylphosphine)palladium as catalysts, tetrahydrofuran and water as solvents, under nitrogen protection, at a temperature of 65~75℃ for 8~12 h.

4. The method for preparing a fluorescent probe according to claim 2, characterized in that: In step two, the conditions for the Suzuki coupling reaction are as follows: using K2CO3 and tetra(triphenylphosphine)palladium as catalysts, tetrahydrofuran and water as solvents, under nitrogen protection, at a temperature of 65~75℃ for 8~12 h.

5. The method for preparing a fluorescent probe according to claim 2, characterized in that: In step three, the conditions for the substitution reaction are: using acetonitrile as solvent, under nitrogen protection, and at a temperature of 70-90°C for 10-12 hours.

6. The application of the fluorescent probe according to claim 1, characterized in that: Fluorescence detection applied to PFOS.

7. The application of a fluorescent probe according to claim 6, characterized in that: This method is applied to the qualitative and quantitative detection of PFOS in complex solution systems containing Na. + K + Ca 2+ Zn 2+ Mg 2+ F - I - SO3 2- CO3 2- SO4 2- HCO3 - Cl - NO2 - NO3 - It contains at least one of the following impurities: PFO, PFBA, FBSA, and PFOA.

Images