Hydroxyaniline modified covalent organic framework material as well as preparation method and application thereof

Abstract

The invention provides a hydroxyaniline-modified covalent organic framework material and a preparation method and application thereof, the hydroxyaniline-modified covalent organic framework material provided by the invention selects a specific monomer for reaction, so that the obtained material is used as an adsorbent to be applied to pretreatment of a phenol-containing EDCs sample; according to the method, the trace phenol EDCs in the sample can be rapidly analyzed, the detection efficiency and sensitivity of the phenol EDCs in the sample are remarkably improved, a reliable scheme is provided for food safety monitoring, and the material can be repeatedly used, so that the cost is greatly saved.

Description

Technical Field

[0001] This invention relates to the field of polymer technology, and in particular to a hydroxyaniline-modified covalent organic framework material, its preparation method, and its application. Background Technology

[0002] Phenolic endocrine disruptors (EDCs) are exogenous substances with estrogenic activity that interfere with the synthesis and metabolism of human hormones. Bisphenol F (BPF), bisphenol A (BPA), bisphenol B (BPB), and p-tert-butylphenol (PTBP) are the most typical examples. They are widely used in food contact materials, such as food can linings, water bottles, and food packaging bags. Phenolic endocrine disruptors are prone to migration and can leach from containers or their linings into food. When humans consume contaminated food, phenolic endocrine disruptors enter the body, interfering with hormone signaling pathways, thereby affecting hormone secretion and ultimately leading to an imbalance in the human endocrine system. China and the European Union stipulate that the migration limit of BPA in food must not exceed 0.05 mg / kg. -1 The tolerable daily intake was set at 4 μg / kg. -1 Given the potential toxicity risks of phenolic endocrine disruptors, developing highly sensitive analytical techniques with low detection limits is of great significance for accurately determining trace amounts of phenolic endocrine disruptors in complex samples and protecting public health.

[0003] Currently, high-performance liquid chromatography (HPLC) is a popular method for detecting phenolic EDCs, and it can be combined with various detectors, such as ultraviolet (UV), diode array (DAD), and mass spectrometry (MS). Among them, HPLC-MS and HPLC-MS / MS have become the preferred technology for detecting phenolic EDCs due to their high recognition ability and separation efficiency for targeted EDCs. However, the purchase, use, and maintenance costs of HPLC-MS / MS are high, making it unsuitable for routine analysis and detection in ordinary laboratories. Therefore, HPLC-MS is a promising instrument for detecting phenolic EDCs. However, phenolic EDCs in food are usually present at trace levels, and food has a complex matrix, so direct detection by instruments is not feasible in most cases. Therefore, pretreatment of complex samples to effectively enrich phenolic EDCs and reduce sample matrix interference is crucial. Compared with other commonly used sample pretreatment techniques such as solid-phase microextraction (SPME), liquid-phase microextraction (LPME), and magnetic solid-phase extraction (MSPE), solid-phase extraction (SPE) has significant advantages in high-throughput sample processing, ease of operation, and reproducibility. The performance of the SPE packing material is a key factor determining the extraction efficiency. To meet the need for detecting trace phenolic EDCs in food, it is crucial to develop a novel high-affinity SPE adsorbent for accurate detection of trace contaminants in food. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a hydroxyaniline-modified covalent organic framework material, its preparation method, and its application. The material provided by the present invention is used for the pretreatment of phenolic EDCs pollutants, enabling rapid analysis of trace phenolic EDCs in samples. This method significantly improves detection efficiency and sensitivity, providing a reliable solution for food safety monitoring.

[0005] Compared with existing technologies, this invention provides a hydroxyaniline-modified covalent organic framework material, its preparation method, and its application. The hydroxyaniline-modified covalent organic framework material provided by this invention is obtained by mixing and reacting 3,3-dihydroxyaniline and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine as monomers. Experimental results show that, by selecting specific monomers, the hydroxyaniline-modified covalent organic framework material provided by this invention can be used as an adsorbent for the pretreatment of phenolic EDCs-containing samples, enabling rapid analysis of trace phenolic EDCs in the samples. This method significantly improves the detection efficiency and sensitivity of phenolic EDCs in samples, providing a reliable solution for food safety monitoring. Furthermore, the material is reusable, greatly saving costs. Attached Figure Description

[0006] Figure 1 This is a schematic diagram illustrating the preparation and application of DT-COF.

[0007] Figure 2 Infrared spectrum of COFS prepared according to the present invention;

[0008] Figure 3 The X-ray diffraction pattern of the COFS prepared in this invention;

[0009] Figure 4 The results of thermal stability analysis of the COFs prepared in this invention;

[0010] Figure 5 The contact angle of the COFs prepared in this invention;

[0011] Figure 6 A comparison chart of the adsorption capacities of different adsorbents;

[0012] Figure 7 To improve the reusability of the DT-COF prepared in this invention;

[0013] Figure 8 The results show the batch repeatability of the DT-COF prepared in this invention. Detailed Implementation

[0014] This invention provides a hydroxyaniline-modified covalent organic framework material, characterized in that the hydroxyaniline-modified covalent organic framework material is prepared by the following method: mixing and reacting 3,3-dihydroxyaniline and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine to obtain the hydroxyaniline-modified covalent organic framework material. The molar ratio of 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine and 3,3-dihydroxyaniline is preferably 1:(1-2), more preferably 1:(1.5-1.8); the solvent for the mixed reaction is preferably one or two of 1,3,5-trimethylbenzene and 1,4-dioxane, more preferably 1,3,5-trimethylbenzene and 1,4-dioxane, wherein the volume ratio of 1,3,5-trimethylbenzene and 1,4-dioxane in the solvent is preferably 1:(1:1.2); the volume ratio of 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine to the solvent is preferably 1 mmol:(25-40) mL, more preferably 1 mmol:(26-30) mL;

[0015] In this invention, it is preferable to further add glacial acetic acid as an additive to the mixing reaction. The ratio of 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine to glacial acetic acid is 1 mmol: (2-3) mL.

[0016] In this invention, the preferred temperature for the mixing reaction is 110–140°C, more preferably 120–130°C, and the preferred reaction time is 50–80 hours, more preferably 60–72 hours. The reaction is preferably carried out under an inert gas atmosphere. Preferably, the crude product obtained after the reaction is completed is further processed to obtain the target product. No special requirements are placed on the processing method; any processing method known in the art is acceptable.

[0017] This invention also provides a method for preparing a hydroxyaniline-modified covalent organic framework material, comprising: reacting 3,3-dihydroxyaniline and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine to obtain the hydroxyaniline-modified covalent organic framework material. In this invention, the limitations on the preparation method are the same as those in the aforementioned product preparation methods.

[0018] This invention also provides a method for detecting phenolic EDC residues in a sample, including pretreatment and detection. The pretreatment is performed by solid-phase extraction on the sample to be tested. The extractant used for solid-phase extraction is the hydroxyaniline-modified covalent organic framework material described in this invention. The detection is performed by HPLC-UV, HPLC-DAD, HPLC-MS, or HPLC-MS / MS.

[0019] This invention provides a hydroxyaniline-modified covalent organic framework material, its preparation method, and its applications. The hydroxyaniline-modified covalent organic framework material (DT-COF) was successfully synthesized by an aldehyde-amine condensation reaction using 3,3-dihydroxyaniline (DT) and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine (TFPT) as monomers. Experiments showed that this material exhibits excellent extraction efficiency for phenolic EDCs, making DT-COF a suitable SPE adsorbent for enriching trace phenolic EDCs (BPF, BPA, PTBP, and BPB) in water, green tea, and milk before HPLC-MS analysis, demonstrating excellent adsorption performance. Therefore, its application in the pretreatment of samples containing phenolic EDCs enables rapid analysis of trace phenolic EDCs. This method significantly improves the detection efficiency and sensitivity of phenolic EDCs in samples, providing a reliable solution for food safety monitoring. Furthermore, the material is reusable, greatly reducing costs.

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1

[0022] 1. Synthesis of hydroxyaniline-modified covalent organic framework (DT-COF)

[0023] TFPT (0.50 mmol) and DT (0.75 mmol) were weighed into a Schlenk reaction flask. Then, 13 mL of a 1,3,5-trimethylbenzene / 1,4-dioxane mixture (1:1, v / v) was added, and the mixture was sonicated to achieve homogenization. Subsequently, 1.3 mL of glacial acetic acid was added, and the resulting mixture was sonicated for another 15 minutes to ensure thorough mixing and dissolution. To minimize interference from water and oxygen, after sonication, the side arm was connected to a double-row tube, and two liquid nitrogen freezing and vacuuming (2 minutes) followed by nitrogen purging (3 minutes) processes were performed. The system was then placed in a high-temperature oven at 120°C for 3 days. After cooling to room temperature, the crude product was obtained by filtration, followed by Soxhlet extraction purification with tetrahydrofuran and methanol, respectively. Finally, DT-COF was obtained by drying in a vacuum oven at 60°C for 24 hours. The preparation method is as follows: Figure 1 As shown, Figure 1 This is a schematic diagram illustrating the preparation and application of DT-COF.

[0024] 2. Comparative Examples 1-2

[0025] Comparative Example 1: Following the above preparation method, only the raw material DT was replaced with raw material BT (benzidine) to prepare BT-COF;

[0026] Comparative Example 2: Following the above preparation method, the amount and type of raw materials were changed. Specifically, an equimolar mixture of TFPT and DT and BT (0.375 mmol each) was prepared to obtain DTB-COF.

[0027] 3. Characterization of COFs

[0028] The successful synthesis of COFs was verified by Fourier transform infrared (FT-IR) spectroscopy. The results are shown in Figure 2. Figure 2 The infrared spectrum of the COFS prepared in this invention shows that BT and DT are at 3392 cm⁻¹. –1 The NH stretching vibration peak and TFPT at 1693 cm⁻¹ –1 The C=O vibration peak at 1560 cm⁻¹ disappears, and the peak at 1560 cm⁻¹ also disappears. –1 Enhanced C=N vibrational bands were observed, confirming the successful synthesis of the three COFs.

[0029] DT-COF, BT-COF, and DTB-COF were analyzed using powder X-ray diffraction (PXRD), and the results are as follows: Figure 3 As shown, Figure 3 The X-ray diffraction patterns of the COFs prepared in this invention are shown in the figure. Strong peaks are observed at 2.55, 2.67, and 2.73 Å, respectively. These diffraction peaks correspond to the "100" crystal plane, confirming the crystal structures of the three COFs.

[0030] The thermal stability of DT-COF was investigated under a nitrogen atmosphere, and the results are as follows: Figure 4 As shown, Figure 4 The results of the thermal stability analysis of the COFs prepared in this invention show that DT-COF exhibits good stability before 300℃.

[0031] The water contact angles of three COF materials were measured, and the results are as follows: Figure 5 As shown, Figure 5 The figure shows the contact angles of the COFs prepared in this invention. As can be seen from the figure, the hydrophilicity order of the materials in this invention is: DT-COF (54°) > DTB-COF (67°) > BT-COF (78°). It is speculated that the hydrophilicity may be affected by the number of -OH functional groups present in the material. This trend can be attributed to the fact that polar groups (-OH) enhance the wettability of the material in water by reducing the surface energy of the material.

[0032] 4. Adsorption Applications

[0033] This study systematically evaluated the adsorption performance of DT-COF, BT-COF, and DTB-COF, as well as several commercial adsorbents (polyphenylene acetate anion exchange resin (PXA), hydrophilic-lipophilic balanced adsorbent (HLB), graphitized carbon black (GCB), and phenolic EDCs). The results are as follows: Figure 6 As shown, Figure 6 This is a comparison of the adsorption capacities of different adsorbents; the graph shows that the extraction recovery rate of DT-COF is significantly higher than that of the other two COF materials. This may be because DT-COF (146.8m) 2 g -1 ) and BT-COF (65.6m 2 g -1 ) and DTB-COF (142.5m 2 g -1 Compared to commercial adsorbents, DT-COF not only has a larger specific surface area but also more hydroxyl active groups, thus providing a richer range of adsorption sites. Furthermore, comparisons with commercial adsorbents show that DT-COF exhibits significantly superior performance. Given its excellent adsorption properties, DT-COF was selected as the adsorbent for subsequent experiments in this study.

[0034] To achieve satisfactory SPE performance, key influencing parameters were optimized, including eluent type, eluent volume, sample solution flow rate, sample solution volume, sodium chloride concentration, and pH. In the optimization experiments, 100 mL of 100 ng / mL eluent was used. -1 An aqueous solution of phenolic EDCs was passed through a SPE column packed with 30 mg of DT-COF. Single-factor optimization was used to optimize the SPE conditions. Each condition was tested in triplicate.

[0035] Ideal experimental conditions: Sample solution pH: no pH adjustment; Sample solution flow rate: 4 mL / min -1 Sample solution volume: 100 mL; Desorption conditions: 0.30 mL methanol; Salt concentration: No adjustment of the salt concentration of the solution.

[0036] DT-COF's reusability and batch stability

[0037] The reusability and batch stability of DT-COF materials are crucial for their cost-effectiveness and environmental friendliness in practical applications. To assess the reusability of DT-COF materials, this study used a SPE column for cyclic experiments. After each SPE cycle, the SPE column was washed sequentially with 1 mL of methanol and 3 mL of water to completely remove residual phenolic EDC. Results Figure 7 As shown, Figure 7To demonstrate the reusability of the DT-COF prepared in this invention, as shown in the figure, the extraction recovery rate of phenolic EDCs remained above 90% after 25 cycles. Furthermore, batch consistency tests were conducted by synthesizing different batches of DT-COF material, and the results are as follows... Figure 8 As shown, Figure 8 The batch stability results of DT-COF described in this invention are shown in the figure. As can be seen from the figure, the extraction efficiency of DT-COF material remains basically unchanged across different batches. This demonstrates that DT-COF has excellent reusability and batch reproducibility, showcasing its application potential in the analytical field.

[0038] The key parameters of the established method (including enrichment factor (EF), limit of detection (LODs), linear range (LR), limit of quantitation (LOQs), and intra-day and inter-day relative standard deviations (RSDs)) were evaluated according to SANTE 11312 / 2021 guidelines (Table 1). Matrix-matched calibration curves were established for water, beverage, and milk samples. The limit of detection (LODs) was defined as three times the signal-to-noise ratio (S / N). The limit of quantitation (LOQs) was defined as the lowest quantifiable concentration of the analyte. The results are shown in Table 1, which presents the analytical data for detecting several common phenolic EDCs in different samples using the method of this invention. As can be seen from Table 1, the LR for phenolic EDCs in bottled water samples ranged from 0.06 to 50 ng / mL. -1 The linear relationship is good (R 2 >0.9972). LOD and LOQ were 0.018-0.031 ng / mL, respectively. -1 and 0.06-0.10 ng mL -1 For green tea beverage samples, it ranges from 0.10 to 50 ng / mL. -1 It exhibits good linearity (R) within the LR range. 2 >0.9972), LOD and LOQ were 0.03-0.07 ng / mL, respectively. -1 and 0.10-0.23 ng / mL -1 For milk samples, the limits of detection and quantitation were 0.057-0.219 ng / mL, respectively. -1 and 0.19-0.72 ng / mL -1 And the linear range is good (0.10-50.0 ng / mL). -1 R 2 >0.9988). The RSD of the current method was assessed by analyzing samples spiked at two levels over one and five days (bottled water: 0.1, 0.5 ng / mL). -1 Green tea beverage: 0.5, 3.0 ng / mL -1 Milk: 1.0 or 5.0 ng / mL-1 The intraday RSD for all three samples was less than 4%, and the interday RSD was less than 5%. The enrichment factor (EF) was expressed as the ratio of the concentration of phenolic EDCs in 0.3 mL of methanol to the concentration of phenolic EDCs in 100 mL of sample solution. The EFs for bottled water, green tea beverage, and milk samples were 179-210, 162-193, and 152-183, respectively.

[0039] Table 1. Analytical data for the detection of phenolic contaminants using the current method (n=5)

[0040] The concentration of phenolic pollutants is measured in ng / mL. -1 .

[0041] Comparison with other literature methods

[0042] Compared with methods reported in the literature, the DT-COF-based SPE-HPLC-MS method developed in this study has significant advantages (Table 2). In terms of analytical performance, the detection limit of this method is lower than that in existing literature [1-7]. From an economic and practical perspective, the method provided by this invention requires only a small amount of elution solvent [2-7], and DT-COF can be reused at least 25 times (superior to [1,4,6,7]), significantly reducing analytical costs and conforming to the concept of green chemistry. More importantly, as a detector, MS is more selective and accurate than UV and DAD. Therefore, the DT-COF-based SPE-HPLC-MS method proposed in this study is suitable for determining phenolic EDCs in food samples, exhibiting high sensitivity and accuracy.

[0043] Table 2 Comparison of this method with other methods

[0044]

[0045] a CN-HIP: Cyano-functionalized porous hypercrosslinked cationic polymer; b Mazo POP: Magnetic azo porous organic polymer; c HQSA-PLE-HCP: Sulfonic acid-based hypercrosslinked polymer; d Fe3O4@COF@R, R=(Cl,Br,I): Halogen-functionalized magnetic covalent organic framework; e TCMP@MIP: Molecularly imprinted conjugated microporous polymer composite material; f MMIP: Magnetic molecularly imprinted polymer; g CNi HCP: A bifunctional hypercrosslinked porous polymer with cyano and ionic groups.

[0046] References

[0047] 1.Cai,Z.,et al.,Synthesis of cyano and ionic dual-functionalhypercrosslinked porous polymer for effective adsorption and detection ofendocrine disrupting chemicals in milk matrix.Journal of Hazardous Materials,2024.462.

[0048] 2.Guo,Y.,et al.,Design of sulfonic group based hyper cross-linkedpolymer as adsorbent for efficient enrichment of endocrinedisrupters.Analytica ChimicaActa,2025.1333.

[0049] 3.Huang,X.-C.,J.-K.Ma,and S.-L.Wei,Preparation and application of anovel magnetic molecularly imprinted polymer for simultaneous and rapiddetermination of three trace endocrine disrupting chemicals in lake water andmilk samples.Analytical and Bioanalytical Chemistry,2020.412(8):p.1835-1846.

[0050] 4.Jiang,H.,et al.,Constructing halogen-functionalization magneticcovalent organic frameworks for enhancing the endocrine disruptors adsorptioncapacity.Food Chemistry,2025.489.

[0051] 5.Wang,C.,et al.,Preparation of amino-functionalized triazine-basedhyper-crosslinked polymer for efficient adsorption of endocrinedisruptors.Talanta,2024.266.

[0052] 6. Xu, M., et al., Molecularly imprinted conjugated microporous polymercomposite as solid phase extraction adsorbent for the extraction of phenolicendocrine disrupting chemicals in beverages. Microchemical Journal, 2023.191.

[0053] 7. Zhao, G., et al., Cyano-functionalized porous hyper-crosslinkedcationic polymers for efficient preconcentration and detection of phenolicendocrine disruptors in fresh water and fish. Talanta, 2025.281.

[0054] 8. Jiang, H., et al., Ultrasonic synthesis of magnetic covalent organic frameworks and application magnetic solid phase extraction for rapidadsorption of trace bisphenols in food samples. Food Chemistry, 2024.440.

[0055] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A hydroxyphenylamine-modified covalent organic framework material, characterized in that, The hydroxyaniline-modified covalent organic framework material is prepared by mixing 3,3-dihydroxyaniline and 2,4,6-tri(4-formylphenoxy)-1,3,5-triazine to obtain the hydroxyaniline-modified covalent organic framework material.

2. The hydroxyphenylamine-modified covalent organic framework material of claim 1, wherein, The solvent of the mixing reaction is one or both of 1,3,5-trimethylbenzene and 1,4-dioxane.

3. The hydroxyphenylamine-modified covalent organic framework material of claim 2, wherein, The ratio of the amount of 2,4,6-tri(4-formylphenoxy)-1,3,5-triazine to the solvent is 1 mmol:(25-40) mL.

4. The hydroxyphenylamine-modified covalent organic framework material of claim 1, wherein, The mixing reaction further adds an additive of glacial acetic acid.

5. The hydroxyphenylamine-modified covalent organic framework material of claim 4, wherein, The ratio of the amount of 2,4,6-tri(4-formylphenoxy)-1,3,5-triazine to the glacial acetic acid is 1 mmol:(2-3) mL.

6. The hydroxyphenylamine-modified covalent organic framework material of claim 1, wherein, The molar ratio of 2,4,6-tri(4-formylphenoxy)-1,3,5-triazine to 3,3-dihydroxyaniline is 1:(1-2).

7. The hydroxyphenylamine-modified covalent organic framework material of claim 1, wherein, The temperature of the mixing reaction is 110-140°C.

8. A method of preparing a hydroxyphenylamine-modified covalent organic framework material, comprising: The hydroxyaniline-modified covalent organic framework material is prepared by mixing 3,3-dihydroxyaniline and 2,4,6-tri(4-formylphenoxy)-1,3,5-triazine.

9. A method for detecting phenolic EDCs residues in a sample, comprising pretreatment and detection, The pretreatment is pretreatment of the sample to be detected by solid phase extraction; the solid phase extraction uses an extractant which is the hydroxyaniline-modified covalent organic framework material of any one of claims 1-7 or the hydroxyaniline-modified covalent organic framework material prepared by the preparation method of claim 8.

10. The detection method according to claim 9, characterized in that, The detection is HPLC-UV method, HPLC-DAD method, HPLC-MS method or HPLC-MS / MS method.

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