Fluorine-functionalized organic framework material, preparation and use thereof

Abstract

This invention relates to the preparation and solid-phase extraction application of a fluorinated functionalized covalent organic framework, belonging to the field of functional materials technology. The fluorinated functionalized covalent organic framework material possesses a high specific surface area and suitable micropore size, and contains abundant fluorine affinity sites and hydrogen bonding sites. It can selectively enrich perfluorinated and polyfluoroalkyl compounds through fluorine-fluorine interactions and hydrogen bonding, and exhibits high chemical stability, enabling efficient adsorption of perfluorinated and polyfluoroalkyl compounds such as perfluorooctanoic acid and perfluorooctane sulfonic acid. Applied to a solid-phase extraction column, it efficiently enriches perfluorinated and polyfluoroalkyl compounds, maintaining good extraction performance even after multiple adsorption-desorption cycles. In practical applications on lake water samples, the solid-phase extraction column combined with UHPLC-MS / MS detection method achieves simultaneous detection of nine perfluorinated and polyfluoroalkyl compounds, exhibiting high recovery rates and a wide linear range.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, specifically relating to the preparation of a fluorinated functionalized covalent organic framework material and its application in the enrichment and detection of perfluorinated and polyfluoroalkyl compounds. Background Technology

[0002] Per- and polyfluoroalkyl substances (PFASs) are fluorocarbons in which all or part of the hydrogen atoms bonded to the carbon atoms of organic molecules are replaced by fluorine atoms. These compounds mainly include perfluorocarboxylic acids and perfluorosulfonic acids. PFASs possess hydrophilic head groups and hydrophobic alkyl side chains, endowing them with unique chemical inertness, thermal stability, and environmental durability, making them widely used in textiles, food packaging, and fire-fighting foams. However, the extremely stable CF bonds in PFASs make them extremely difficult to degrade in natural environments (half-lives can reach decades), and they exhibit strong bioaccumulation, causing hepatotoxicity, reproductive toxicity, and carcinogenic risks, posing a significant challenge to aquatic ecosystems, animal organisms, and human health.

[0003] Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS / MS) has become the primary analytical method for detecting PFASs due to its high resolution and sensitivity. However, effectively enriching, separating, and detecting trace levels of PFASs in environmental and food samples remains challenging due to interference from complex matrices. Therefore, the selection of efficient pretreatment methods is extremely important, especially the choice of solid-phase extraction (SPE) adsorbents. Currently available commercial adsorbents, such as activated carbon and anion exchange resins, have drawbacks such as long equilibration times, insufficient selectivity, and relatively poor regeneration capabilities. Therefore, the need for developing novel, highly efficient adsorbents is growing.

[0004] Covalent organic frameworks (COFs) are porous crystalline materials composed of light elements such as C, N, O, and B linked by covalent bonds. COFs possess advantages such as ordered porous structures, high specific surface areas, and ease of modification, making them highly promising for the adsorption of PFASs. However, traditional COFs lack fluorine affinity sites, resulting in poor specificity for PFASs, and some COFs exhibit insufficient stability, thus limiting their adsorption efficiency for PFASs in aquatic environments.

[0005] Therefore, it is of great significance to develop a COFs-based adsorbent that combines broad-spectrum affinity with high efficiency and stability. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a fluorinated functionalized covalent organic framework material, its preparation method, and its applications. This fluorinated functionalized covalent organic framework material exhibits excellent affinity for various anionic perfluorinated and polyfluoroalkyl compounds, and its inherent enol-ketone tautomerism effectively enhances its chemical stability and multifunctionality. As a solid-phase extraction column adsorbent, the fluorinated functionalized covalent organic framework material is used for the efficient enrichment of trace perfluorinated and polyfluoroalkyl compounds in complex matrices. Coupled with UHPLC-MS / MS, it enables rapid and sensitive analytical detection of perfluorinated compounds.

[0007] The first aspect of this invention provides a fluorinated functionalized covalent organic framework material having the following structural units:

[0008]

[0009] Furthermore, the fluorinated covalent organic framework material has a loose network structure with pore sizes distributed between 1-2 nm, mainly distributed at 1.2 nm, which belongs to a microporous structure;

[0010] In some embodiments, the BET specific surface area of ​​the fluorinated covalent organic framework material is ≥1395 m². 2 g -1 .

[0011] In some embodiments, the BET specific surface area of ​​the fluorinated covalent organic framework material is 1395-2161 m². 2 g -1 .

[0012] The second objective of this invention is to provide a method for preparing a fluorinated functionalized covalent organic framework material. Using trialdehyde-based phloroglucinol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl as raw materials, a covalent organic framework material containing a trifluoromethyl group is generated under the action of a catalyst.

[0013] Furthermore, the preparation method of the fluorinated functionalized covalent organic framework material includes the following steps: S11. Dispersing two organic ligands, trialdehyde phloroglucinol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, in a reaction solvent to obtain a dispersion; S12. Adding a catalyst to the dispersion to react and obtain a reaction system; reacting at a certain temperature for 3-5 days; after separation and purification, the fluorinated functionalized covalent organic framework material is obtained.

[0014] In some embodiments, in step S11, the molar ratio of trialdehyde phloroglucinol and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl is 2:1 to 2:3.

[0015] In some embodiments, in step S11, the reaction solvent is a mixed solution of o-dichlorobenzene and n-butanol, and the volume ratio of o-dichlorobenzene to n-butanol is 1:1 to 1:3.

[0016] In some embodiments, in step S12, the catalyst is an acetic acid solution, preferably with a concentration of 3-12 mmol / L. -1 ;

[0017] In some embodiments, the reaction temperature in step S12 is 100°C-150°C.

[0018] In some embodiments, in step S12, the separation and purification step involves washing and drying the precipitate with tetrahydrofuran and n-hexane after centrifugation.

[0019] The third objective of this invention is to provide an application of the fluorinated functionalized covalent organic framework material in gas storage, separation, and catalysis.

[0020] In some embodiments, the fluorinated covalent organic framework material is used as an adsorbent in the separation field for the extraction and analysis of perfluorinated and polyfluoroalkyl compounds; or it is applied to the detection of PFASs in complex matrices.

[0021] Furthermore, the perfluorinated and polyfluoroalkyl compounds include, but are not limited to, one or a combination of perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorohexanesulfonic acid, perfluorooctanesulfonic acid, and 6:2 fluorosulfonic acid.

[0022] Furthermore, the method for detecting and analyzing PFASs using the fluorinated functionalized covalent organic framework material as a solid-phase extraction adsorbent includes the following steps:

[0023] S21. Preparation of solid phase extraction column: Fluorine-functionalized covalent organic framework material is loaded into a solid phase extraction tube, methanol solution is added to wet the material, making the material compact, and after the methanol flows out, a sieve plate is added to obtain a solid phase extraction column.

[0024] S22. Preparation of the test solution: Weigh the homogenized sample, add the internal standard solution, then add the solvent to extract. After evaporating the extract to dryness, reconstitute it to obtain the test solution.

[0025] S23. After adding the test solution to the solid phase extraction column prepared in step S21 to complete the adsorption, the target analyte is eluted and collected; the target analyte in the eluent is detected.

[0026] In some embodiments, in step S22, the extraction solvent is selected from acetonitrile, 2% formic acid acetonitrile, and 90% aqueous acetonitrile solution;

[0027] In some embodiments, in step S22, vortex oscillation and ultrasonic treatment are used to improve extraction efficiency; the vortex oscillation time is 3-5 min; the ultrasonic treatment time is 10-20 min.

[0028] In some preferred embodiments, after vortex oscillation for 10 minutes, ultrasonic treatment is performed for 15 minutes (40 kHz).

[0029] In some embodiments, in step S22, the resolution step uses a mixed solvent of methanol and ultrapure water for resolution; in a preferred embodiment, the volume ratio of methanol to ultrapure water is 1:11.

[0030] In some embodiments, in step S22, the internal standard solution is a carbon-13 isotope internal standard solution with a concentration of 100-300 μg / L;

[0031] In some embodiments, in step S23, the pH of the solution to be tested is 2-9; preferably, the pH is 3-6.

[0032] In some embodiments, in step S23, the eluent is a mixed solution of ammonia and methanol, wherein the volume percentage of ammonia and methanol is 0%-4%; preferably 0.5%-1%.

[0033] In one embodiment, the extraction analysis of perfluorinated and polyfluoroalkyl compounds includes the following steps: (1) fluorinated functionalized covalent organic framework material is loaded into a polyethylene solid-phase extraction tube, methanol solution is slowly added to wet the material, and the material is compacted by slight vibration. After the methanol is dried, a sieve plate is added to obtain a solid-phase extraction column; (2) 5-10 g of fully homogenized sample is accurately weighed into a polypropylene centrifuge tube, an appropriate amount of carbon-13 isotope internal standard solution is added, and 4-10 mL of acetonitrile solution is added and mixed. After vortexing for 10 min, the sample is sonicated for 15 min (40 kHz), centrifuged (9000 rpm, 8 min), and the supernatant is transferred to another polypropylene centrifuge tube; the extract is gently evaporated to dryness under a nitrogen flow at 40-60 °C, and 0.5 mL of methanol and 5.5 mL of ultrapure water are added to reconstitute; (3) the target analytes are detected using UHPLC-MS / MS.

[0034] In some embodiments, the liquid chromatography conditions for detecting the target analyte using UHPLC-MS / MS are as follows: column: Athena UHPLC C18 column (100 mm × 2.1 mm, 1.8 μm); mobile phase: 2 mmol / L. -1 Ammonium acetate aqueous solution (A) and acetonitrile (B). Flow rate: 0.3 mL / min. -1The elution gradient program was 0-14 min, 80% A; 14-16 min, 10% A; 16-16.01 min, 80% A; 16.01-20 min, 80% A. The injection volume was 5 μL, and the column oven was set to 40℃.

[0035] In some embodiments, the mass spectrometry conditions for detecting the target analytes using UHPLC-MS / MS are as follows: electrospray ionization source, negative ion mode, ion source temperature of 550°C, spray voltage of -4500V, curtain gas pressure of 35.0psi, nebulizer gas pressure of 55.0psi, and auxiliary gas pressure of 60psi; detection is performed in multiple reaction monitoring mode, and PFASs are quantified using the internal standard method.

[0036] Beneficial effects:

[0037] This invention provides a fluorinated functionalized covalent organic framework material with a high specific surface area and suitable micropore size; the enol-ketone tautomerism of the fluorinated functionalized covalent organic framework material of this invention has high chemical stability and the preparation method is simple;

[0038] The fluorinated functionalized covalent organic framework material contains abundant trifluoromethyl groups, hydrogen bond acceptors and donor sites, and can selectively enrich PFASs through fluorine-fluorine interactions and hydrogen bonding, thereby achieving efficient adsorption of PFASs such as perfluorooctanoic acid and perfluorooctane sulfonic acid.

[0039] When the fluorinated covalent organic framework material provided by this invention is applied to solid-phase extraction of PFASs, it can be reused as a solid-phase extraction column packing material. After 10 adsorption-desorption cycles, the recovery rate still remains above 80%, demonstrating good stability and recyclability.

[0040] This invention provides a method for the quantitative analysis of trace PFASs in complex matrices based on solid-phase extraction combined with UHPLC-MS / MS using fluorine-functionalized covalent organic framework materials. This method is suitable for the simultaneous determination of PFASs such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). The method exhibits a wide linear range (0.05-250 μg / L). -1 It has good stability and precision. Attached Figure Description

[0041] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0042] Figure 1 This is a schematic diagram of the preparation and solid-phase extraction process of the fluorinated functionalized covalent organic framework material in Example 1;

[0043] Figure 2This is a structural diagram of the fluorinated functionalized covalent organic framework material of Example 1;

[0044] Figure 3 The X-ray diffraction pattern of the fluorine-functionalized covalent organic framework material prepared in Example 1;

[0045] Figure 4 The nitrogen adsorption-desorption isotherm and pore size distribution of the fluorinated functionalized covalent organic framework material prepared in Example 1 are shown below.

[0046] Figure 5 The Fourier transform infrared spectrum of the fluorinated functionalized covalent organic framework material prepared in Example 1;

[0047] Figure 6 The X-ray photoelectron spectrum of the fluorine-functionalized covalent organic framework material prepared in Example 1 is shown below.

[0048] Figure 7 Thermogravimetric analysis curves of the fluorinated functionalized covalent organic framework material prepared in Example 1;

[0049] Figure 8 SEM images and elemental distribution diagrams of the fluorinated functionalized covalent organic framework material prepared in Example 1;

[0050] Figure 9 The effects of pretreatment conditions on the extraction efficiency of perfluorinated compounds by a solid-phase extraction column based on fluorine-functionalized covalent organic framework materials are shown in Figure a, where solution pH is represented; adsorbent dosage is represented; elution solvent ratio is represented; and elution solvent volume is represented.

[0051] Figure 10 This is a diagram illustrating the recycling effect of a solid-phase extraction column based on fluorine-functionalized covalent organic framework materials. Detailed Implementation

[0052] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0053] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0054] Example 1: Preparation of fluorine-functionalized covalent organic framework materials:

[0055] Trialdehyde phloroglucinol (0.42 g, 2.0 mmol) and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (0.96 g, 3.0 mmol) were added to a high-temperature resistant glass tube, followed by a mixture of o-dichlorobenzene and n-butanol (1:1, v / v, 2.0 mL total), and then 2.0 mL of acetic acid solution (6.0 mmol L). -1 The glass tube was frozen in liquid nitrogen, evacuated, and thawed, and this process was repeated three times before the glass tube was sealed. It was then allowed to naturally return to room temperature and placed in an oil bath (120°C) for three days to react. The resulting reaction product was washed three times with tetrahydrofuran and n-hexane, then collected by filtration and vacuum dried for 12 hours to obtain a bright yellow powdery fluorinated covalent organic framework material (TpBTFDA COF).

[0056] Tests on the fluorinated functionalized covalent organic framework material prepared in Example 1:

[0057] The structure of TpBTFDA COF is as follows: Figure 2 As shown in the figure, the one-dimensional channel of TpBTFDA COF is displayed. Figure 2 (Left side) and the stacking method between TpBTFDA COF layers ( Figure 2 (Right side), where C, N, O, and F are black, blue, red, and green spheres, respectively, and trifluoromethyl groups can be observed to be evenly distributed on the material skeleton.

[0058] The X-ray diffraction pattern of TpBTFDA COF in Example 1 is as follows: Figure 3 As shown, the prepared TpBTFDACOF exhibits good crystallinity and a distinct diffraction peak at 3.72°. The pore structure characteristics of TpBTFDA COF were characterized, and the results are as follows: Figure 4 As shown, the nitrogen adsorption-desorption isotherm experiment results indicate that its BET specific surface area is 1395 m². 2 g -1 The pore size is mainly distributed at 1.2 nm, which belongs to the microporous structure.

[0059] Fourier transform infrared spectroscopy was used to verify the changes and formation of COF linkages and modifying groups. The results are as follows: Figure 5 As shown, at 1585cm -1 and 1274cm -1 The absorption peaks appearing at 1126 cm⁻¹ are attributed to C=C and CN, indicating a successful enol-ketone tautomerism transformation in the material. -1 The absorption peak appearing at this point is attributed to CF, indicating the presence of the trifluoromethyl group.

[0060] X-ray photoelectron spectrum as follows Figure 6As shown, the presence of the F element peak further indicates the presence of the trifluoromethyl group. Figure 7 Thermogravimetric analysis (TGA) curves of TpBTFDA COF are shown, indicating that TpBTFDA COF possesses good thermal stability (400℃). SEM images are also provided. Figure 8 The results show that TpBTFDA COF has a unique fluffy network structure, and the EDS elemental distribution map shows that the F element is evenly distributed throughout the COF skeleton.

[0061] In another embodiment, nitrogen adsorption-desorption isotherm experiments showed that its BET specific surface area was 2161 m². 2 g -1 .

[0062] Example 2: Extraction of 9 perfluorinated compounds using fluorinated functionalized covalent organic framework materials:

[0063] 8 mg of the TpBTFDA COF material prepared in Example 1 was filled into a 3 mL polyethylene solid-phase extraction tube. 2 mL of methanol solution was slowly added to wet the material. The material was then gently shaken to make it compact. After the methanol was drained, a sieve plate was added and the tube was compacted to obtain a solid-phase extraction column.

[0064] Nine PFASs (perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorohexanesulfonic acid, perfluorooctanesulfonic acid, and 6:2 fluorosulfonic acid) standard solutions were added to ultrapure water to prepare a mixed standard. After vortex mixing, the pH was adjusted to 3 to obtain the loading solution. The loading solution was added to the solid phase extraction column by a vacuum pump. After adsorption was completed, an appropriate amount (1 mL, 2 mL, 3 mL, 4 mL, 5 mL) of methanol solution containing 0.1% ammonia was added. The eluent was collected, dried by nitrogen blowing, reconstituted with methanol solution, and filtered through a 0.22 μm filter membrane to obtain the test solution, which was then analyzed by UHPLC-MS / MS.

[0065] Liquid chromatography conditions: Column: Athena UHPLC C18 column (100 mm × 2.1 mm, 1.8 μm); Mobile phase: 2 mmol / L -1 Ammonium acetate aqueous solution (A) and acetonitrile (B). Flow rate: 0.3 mL / min. -1 The elution gradient program was 0-14 min, 80% A; 14-16 min, 10% A; 16-16.01 min, 80% A; 16.01-20 min, 80% A. The injection volume was 5 μL, and the column oven was set to 40℃.

[0066] Mass spectrometry conditions: Electrospray ionization (ESI) source, negative ion mode, ion source temperature 550℃, spray voltage -4500V, curtain gas pressure 35.0psi, nebulizer gas pressure 55.0psi, auxiliary gas pressure 60psi. Detection was performed in multiple reaction monitoring (MRM) mode, with PFASs quantified using the internal standard method.

[0067] Example 3: Parameter optimization of solid-phase extraction of PFASs from fluorinated covalent organic framework materials:

[0068] The parameters for solid-phase extraction of PFASs based on fluorine-functionalized covalent organic framework materials were optimized, including the pH of the loading solution (2-9), the amount of adsorbent (4-12 mg), the eluent ratio (0-4% ammonia in methanol solution) and the eluent volume (1-5 mL).

[0069] The results of the extraction condition optimization are shown in Figure 9 The results showed that the optimal parameters for solid-phase extraction of perfluorinated compounds based on fluorinated functionalized covalent organic framework materials were: pH of the loading solution was 3, the adsorbent loading amount was 8 mg, the eluent was a methanol solution of 0.1% ammonia, and the eluent volume was 4 mL.

[0070] Table 1. Analytical performance of solid-phase extraction combined with UHPLC-MS / MS method based on fluorine-functionalized covalent organic framework materials.

[0071]

[0072] Table 1 presents the methodological evaluation of PFASs based on solid-phase extraction combined with UPLC-MS / MS using fluorinated functionalized covalent organic framework materials. As shown in Table 1, under optimal conditions, this method exhibits a wide linear range (0.05-250 μg L⁻¹). -1 It exhibits good stability and precision (intra-day and inter-day RSDs of 0.9%-3.4% and 2.6%-5.1%, respectively).

[0073] Example 4: Cyclic performance of a solid-phase extraction column based on a fluorine-functionalized covalent organic framework material:

[0074] The solid-phase extraction column prepared in Example 2 was used for reuse experiments. The column was regenerated by sequentially washing it with 3 mL of a 0.1% ammonia solution in methanol, methanol, and ultrapure water. The extraction procedure of Example 2 was repeated, and the recovery rate of perfluorinated compounds after multiple adsorption-desorption cycles was compared. Figure 10 As shown, after 10 adsorption-desorption cycles, the recovery rate of the nine perfluorinated compounds by the solid-phase extraction column remained above 80%, indicating that the fluorine-functionalized covalent organic framework material has good stability and recyclability.

[0075] Example 5: Recovery of PFASs by solid-phase extraction combined with UHPLC-MS / MS:

[0076] Weigh 5g of the fully homogenized sample (lake water sample) into a polypropylene centrifuge tube, and add an appropriate amount of carbon-13 isotope internal standard solution (200μg / L). -1 A mixed standard solution of nine PFASs was prepared, and 5 mL of acetonitrile solution was added and mixed well. The mixture was vortexed for 10 min, sonicated for 15 min (40 kHz), centrifuged (9000 rpm, 8 min), and the supernatant was transferred to another polypropylene centrifuge tube. The extract was gently evaporated to dryness under a nitrogen stream at 40-60℃, and then reconstituted with 0.5 mL of methanol and 5.5 mL of ultrapure water. The extraction procedure in Example 2 was repeated, and the purified solution was analyzed by UHPLC-MS / MS.

[0077] Table 2. Spike recoveries of nine PFASs in lake water samples

[0078]

[0079] Table 2 shows the recoveries of the nine PFASs spiked in the actual sample. Under optimal conditions, the recoveries of the nine PFASs at three levels (0.05, 0.5, and 5 μg L) were achieved. -1 The spiked recoveries were 79.0-108.9%, and the RSD was less than 9.5%, indicating that the analytical method established in this invention has good accuracy and can be used for the detection of trace PFASs in actual samples.

[0080] This invention provides a fluorinated functionalized covalent organic framework material, its preparation method, and its applications. This material exhibits good affinity for various anionic perfluorinated and polyfluoroalkyl compounds, and its enol-ketone tautomerism enhances its chemical stability and multifunctionality. The material possesses a high specific surface area and suitable micropore size, making it suitable as an adsorbent for the efficient enrichment of trace perfluorinated and polyfluoroalkyl compounds in complex matrices using solid-phase extraction columns. Coupled with UHPLC-MS / MS, it enables rapid and sensitive analysis and detection of PFASs. Furthermore, it demonstrates good stability and recyclability; after 10 adsorption-desorption cycles, the recovery rate remains above 80%, exhibiting a wide linear range (0.05-250 μg / L). -1 It has good stability and precision.

[0081] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. Use of a fluorofunctional covalent organic framework material for the extraction analysis of perfluoro- and polyfluoroalkyl compounds, characterized in that, The fluorine-functionalized covalent organic framework material is used as an adsorbent for extraction analysis of perfluoroalkyl and polyfluoroalkyl compounds. The fluorine-functionalized covalent organic framework material has the following structural unit: 。 2. Use of the fluoro-functional covalent organic frameworks material according to claim 1 for the extraction analysis of perfluoro and polyfluoroalkyl compounds, characterized in that, having a fluffy network structure, pore size distribution in 1-2 nm; BET specific surface area ≥ 1395 m 2 g -1 .

3. Use of the fluoro-functional covalent organic frameworks material according to claim 1 for the extraction analysis of perfluoro and polyfluoroalkyl compounds, characterized in that, The preparation method of the fluorine-functionalized covalent organic framework material comprises the following steps: S11. Disperse two organic ligands, tri-aldehyde-based phloroglucinol and 2, 2'-bis(trifluoromethyl)-4, 4'-diaminobiphenyl, in a reaction solvent to obtain a dispersion liquid; S12. Add the dispersion liquid to a catalyst to obtain a reaction system; react for 3-5 days at a certain temperature; and separate and purify to obtain the fluorine-functionalized covalent organic framework material.

4. Use of the fluoro-functional covalent organic frameworks according to claim 3 for the extraction analysis of perfluoro- and polyfluoroalkyl compounds, characterized in that, In step S11, the molar ratio of tri-aldehyde-based phloroglucinol to 2, 2'-bis(trifluoromethyl)-4, 4'-diaminobiphenyl is 2:1-2:3; And / or, in step S11, the reaction solvent is a mixed solution of o-dichlorobenzene and n-butanol, and the volume ratio of o-dichlorobenzene to n-butanol is 1:1-1:

3.

5. The fluorine-functionalized covalent organic framework material for extraction analysis of perfluoroalkyl and polyfluoroalkyl compounds according to claim 3, wherein In step S12, the catalyst is acetic acid solution, concentration is 3-12 mmol L -1 ; And / or, in step S12, the reaction temperature is 100-150 ℃.

6. Use of the fluoro-functional covalent organic frameworks material according to claim 1 for the extraction analysis of perfluoro and polyfluoroalkyl compounds, characterized in that, The perfluoroalkyl and polyfluoroalkyl compounds include one or a combination of perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorohexanesulfonic acid, perfluorooctanesulfonic acid, and 6:2 fluorotriglycolic acid.

7. Use of the fluoro-functional covalent organic frameworks material according to claim 6 for the extraction analysis of perfluoro and polyfluoroalkyl compounds, characterized in that, The fluorine-functionalized covalent organic framework material is used as a solid-phase extraction adsorbent; The analysis method of perfluoroalkyl and polyfluoroalkyl compounds comprises the following steps: S21. Prepare a solid-phase extraction column: load the fluorine-functionalized covalent organic framework material into a solid-phase extraction empty tube, add a methanol solution to wet the material, make the material compact, add a sieve plate after the methanol flows dry, and prepare the solid-phase extraction column; S22. Prepare a test solution: weigh the homogenized sample, add an internal standard solution, and then add the extracted solution after solvent extraction to obtain the test solution; S23. Add the test solution to the solid-phase extraction column prepared in step S21 to complete adsorption, elute and collect the target substance, and detect the target substance in the eluent.

8. Use of the fluoro-functional covalent organic frameworks according to claim 7 for the extraction analysis of perfluoro- and polyfluoroalkyl compounds, characterized in that, In step S22, the extraction solvent is selected from acetonitrile, 2% formic acid acetonitrile v / v, and 90% acetonitrile aqueous solution v / v; And / or, in step S22, vortex oscillation and ultrasonic treatment are used to improve the extraction efficiency; the vortex oscillation time is 3-5 min; and the ultrasonic treatment time is 10-20 min.

9. The fluorine-functionalized covalent organic framework material for extraction analysis of perfluoroalkyl and polyfluoroalkyl compounds according to claim 7, wherein in step S22, the concentration of the carbon 13 isotope internal standard solution is 100-300 μg / L.

10. Use of the fluoro-functional covalent organic frameworks material according to claim 8 for the extraction analysis of perfluoro and polyfluoroalkyl compounds, characterized in that, In step S23, the pH of the test solution is 2-9; And / or, in step S23, the eluent is a mixed solution of ammonia water and methanol, and the volume percentage of ammonia water to methanol is 0%-4%.

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