A fluorinated squaramide covalent organic framework material and its preparation method and application

Abstract

The present invention provides a fluorinated squaramide covalent organic framework material, a preparation method and an application thereof. The fluorinated squaramide covalent organic framework material has a structure as shown in formula (I). The fluorinated squaramide covalent organic framework material has a suitable micropore size, has a better affinity for a variety of synthetic cannabinoids SCs, and its own enol-ketone tautomerism effectively improves the chemical stability and versatility. The solid phase microextraction coating probe prepared with the fluorinated squaramide covalent organic framework material can selectively and efficiently extract SCs under different pH conditions or in the coexistence of interfering substances, and can maintain good extraction performance under various interference conditions. In actual wastewater applications, excellent recovery rates have been achieved, and trace determination of SCs can be easily achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of covalent organic framework functional materials, and in particular relates to a fluorinated squaramide covalent organic framework material and a preparation method and application thereof. Background Art

[0002] Synthetic cannabinoids (SCs) are the most widely used cannabis substance worldwide, with an estimated 192 million users in 2018. SCs act on the same brain receptors as tetrahydrocannabinol (THC) but have more potent pharmacological effects than natural cannabinoids, leading to dangerous side effects such as kidney failure, heart attack, psychosis, and in some cases, death. Many countries, such as the United States, New Zealand, and China, have amended their laws to prohibit SCs. Given the serious risks posed by SCs, more sensitive and advanced detection technologies are urgently needed for effective monitoring.

[0003] Wastewater-based epidemiology (WBE) is an effective surveillance method for estimating the total consumption of SCs in a community. It provides near-real-time, unbiased assessments of consumption and has successfully assessed the consumption of illicit drugs, tobacco, and other addictive substances. WBE analysis of SCs is commonly performed using mass spectrometry (MS) coupled with gas chromatography (GC) or liquid chromatography (LC). Consequently, improving sample pretreatment techniques to enhance separation efficiency has received increasing attention.

[0004] Traditional liquid-liquid extraction (LLE) techniques require large amounts of organic solvents and derivatization procedures, making it difficult to extract highly water-soluble substances from water. Some researchers have used neutral hydrophilic-lipophilic balance (HLB) or mixed-mode cation exchange (MCX) cartridges as solid-phase extraction (SPE) materials to cover the physicochemical properties of target SCs. Specifically, HLB cartridges are widely used and do not require advanced acidification steps, but their extraction efficiency for SCs is relatively low. MCX cartridges exhibit some selectivity for SCs. However, wastewater samples must be acidified (pH 2-5), and MCX cartridges require pretreatment (first with methanol, then with acidified water). A few adsorbents, such as molecularly imprinted polymers (MIPs) and metal-organic frameworks (MOFs), have been applied to the solid-phase extraction of SCs to avoid complex derivatization procedures and reduce time consumption. Due to the chemical diversity, rapid emergence and evolution of SCs, and the complexity of matrices, existing adsorbents struggle to meet the requirements of broad spectrum, high sensitivity, and matrix-free performance. Therefore, a high-performance adsorbent with broad affinity is needed to enable specific recognition of diverse SCs in complex matrices. Summary of the Invention

[0005] In response to the above-mentioned existing technical problems, the primary purpose of the present invention is to provide a fluorinated squaramide covalent organic framework material, which has better affinity for various SCs, and its own enol-keto tautomerism properties effectively improve the chemical stability and versatility. The solid phase microextraction probe based on the fluorinated squaramide covalent organic framework material can easily achieve trace determination of synthetic cannabinoids (SCs).

[0006] The second object of the present invention is to provide a method for preparing a fluorinated squaramide covalent organic framework material.

[0007] The third object of the present invention is to provide the use of the fluorinated squaramide covalent organic framework material as an adsorbent in the preparation of solid phase microextraction coatings, in the preparation of solid phase microextraction probes, in solid phase microextraction of synthetic cannabinoids, or in the detection of synthetic cannabinoids.

[0008] The fourth object of the present invention is to provide a solid phase microextraction coating based on a fluorinated squaramide covalent organic framework material.

[0009] A fifth object of the present invention is to provide a solid phase microextraction probe based on the solid phase microextraction coating.

[0010] A sixth object of the present invention is to provide use of the above-mentioned solid phase microextraction coating or solid phase microextraction probe in solid phase microextraction of synthetic cannabinoids or in the detection of synthetic cannabinoids.

[0011] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0012] A fluorinated squaramide covalent organic framework material, wherein the fluorinated squaramide covalent organic framework material has a structure as shown in formula (I):

[0013]

[0014] Furthermore, the present invention claims protection for a method for preparing a fluorinated squaramide covalent organic framework material, comprising uniformly mixing Diamine (1), 2,4,6-triformylphloroglucinol, and a reaction solvent, adding an acid solution, reacting at 115-125° C. for 3-5 days, and post-treating to obtain the fluorinated squaramide covalent organic framework material;

[0015] The reaction solvent is 1,2-dichlorobenzene and N,N-dimethylacetamide; the concentration of the acid solution is 6 to 17.5 mol / L; the molar ratio of Diamine (1) to 2,4,6-triformylphloroglucinol is 3:2; and the reaction formula is as follows:

[0016]

[0017] Preferably, the acid solution is acetic acid solution.

[0018] Preferably, the reaction temperature is 120°C, and the concentration of the acid solution is 5-7 mol / L or 11-13 mol / L. Further preferably, the concentration of the acid solution is 6 mol / L or 12 mol / L.

[0019] Preferably, the volume mass ratio of 1,2-dichlorobenzene to Diamine (1) is (0.03-0.05):1 mL / mg; the volume mass ratio of N,N-dimethylacetamide to Diamine (1) is (0.01-0.03):1 mL / mg. Further preferably, the volume mass ratio of 1,2-dichlorobenzene to Diamine (1) is 0.038:1 mL / mg; the volume mass ratio of N,N-dimethylacetamide to Diamine (1) is 0.019:1 mL / mg. Furthermore, the present invention requests protection for the use of the fluorinated squaramide covalent organic framework material as an adsorbent in the preparation of solid phase microextraction coatings, in the preparation of solid phase microextraction probes, in solid phase microextraction of synthetic cannabinoids, or in the detection of synthetic cannabinoids.

[0020] Furthermore, the present invention also claims protection for a solid-phase microextraction coating comprising the aforementioned fluorinated squaramide covalent organic framework material and a binder. In the present invention, the fluorinated squaramide covalent organic framework material is used as an adsorbent to prepare the solid-phase microextraction coating. More specifically, the ratio of the adsorbent to the binder in the solid-phase microextraction coating can be prepared according to conventional ratios used in solid-phase microextraction coatings in the art.

[0021] Furthermore, the volume ratio of the fluorinated squaramide covalent organic framework material to the binder is (199-332):1.

[0022] Preferably, the binder is polydimethylsiloxane.

[0023] Furthermore, the present invention also seeks to protect a solid phase microextraction probe, comprising a carrier and the solid phase microextraction coating.

[0024] Preferably, the carrier can be selected from carriers conventionally used in solid phase microextraction in the art. More specifically, the carrier can be stainless steel wire or the like.

[0025] Furthermore, the present invention also claims protection for a method for preparing a solid phase microextraction probe, wherein an adhesive and a solvent are mixed and dispersed to obtain a viscous solution, the viscous solution is coated or adhered to the surface of a carrier, and then an adsorbent is adhered to the surface of the carrier through the viscous solution, and the adsorbent is heated and solidified to evaporate the solvent to obtain the solid phase microextraction probe.

[0026] Preferably, the solvent is cyclohexane.

[0027] Preferably, the temperature of the heating and curing is 70 to 90° C.; and the time of the heating and curing is 20 to 40 minutes.

[0028] Furthermore, the present invention seeks to protect the use of the solid phase microextraction coating or the solid phase microextraction probe in solid phase microextraction of synthetic cannabinoids or in the detection of synthetic cannabinoids.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a fluorinated squaramide covalent organic framework material, which has a suitable micropore size, has a better affinity for a variety of SCs, and its own enol-ketone tautomerism properties effectively improve the chemical stability and versatility. The solid phase microextraction probe prepared with the fluorinated squaramide covalent organic framework material can selectively and efficiently extract SCs under different pH conditions or in the coexistence of interfering substances, and can maintain good extraction performance under various interference conditions. In actual wastewater applications, excellent recovery rates have been achieved, and trace amounts of synthetic cannabinoids (one trillionth, 10 -9 ) determination. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the synthesis of FSQ-2, FSQ-3 and FSQ-4.

[0031] Figure 2 The simulated structures (AA or AB stacking) and corresponding PXRD patterns of FSQ-2, FSQ-3, and FSQ-4 are shown. Figure a shows the simulated structure (AA or AB stacking) and corresponding PXRD pattern of FSQ-2; Figure b shows the simulated structure (AA or AB stacking) and corresponding PXRD pattern of FSQ-3; and Figure c shows the simulated structure (AA or AB stacking) and corresponding PXRD pattern of FSQ-4.

[0032] Figure 3 Figure 1 shows the nitrogen adsorption and desorption isotherms of FSQ-2, FSQ-3, and FSQ-4. Figure a shows the nitrogen adsorption and desorption isotherm of FSQ-2, Figure b shows the nitrogen adsorption and desorption isotherm of FSQ-3, and Figure c shows the nitrogen adsorption and desorption isotherm of FSQ-4.

[0033] Figure 4 The pore size distribution histograms of FSQ-2, FSQ-3, and FSQ-4 are shown in Figure a, which is the pore size distribution histogram of FSQ-2; Figure b is the pore size distribution histogram of FSQ-3; and Figure c is the pore size distribution histogram of FSQ-4.

[0034] Figure 5SEM and TEM images of FSQ-2, FSQ-3, and FSQ-4.

[0035] Figure 6 is the water contact angle of FSQ-2, FSQ-3 and FSQ-4.

[0036] Figure 7 TEM-EDS element maps of FSQ-2, FSQ-3, and FSQ-4.

[0037] Figure 8 Figure 1 shows the C1s XPS spectra and FT-IR spectra of FSQ-2, FSQ-3, and FSQ-4. Figure a shows the C1s XPS spectra of FSQ-2, FSQ-3, and FSQ-4; Figures b, c, and d show the FT-IR spectra of FSQ-2, FSQ-3, and FSQ-4, respectively.

[0038] Figure 9 These are the thermogravimetric analysis curves of FSQ-2, FSQ-3, and FSQ-4.

[0039] Figure 10 SEM images of FSQ-2, FSQ-3, and FSQ-4 SPME probes.

[0040] Figure 11 Comparison results of the enrichment factors of commercial PA, PDMS, DVB / CAR / PDMS, DVB / PDMS, FSQ-2, FSQ-3 and FSQ-4 probes for SCs.

[0041] Figure 12 Figures 1 and 2 show the TEM-EDS, C1s XPS, and I 3d XPS spectra of AM-2233 after adsorption / extraction by FSQ-4. Figure a shows the TEM-EDS spectrum of AM-2233 adsorbed by FSQ-4; Figures b and c show the C1s XPS spectra of AM-2233 extracted by FSQ-4; and Figures d and e show the I 3d XPS spectra of AM-2233 extracted by FSQ-4.

[0042] Figure 13 is the molecular size of the target SCs.

[0043] Figure 14 is the surface electrostatic potential of SCs.

[0044] Figure 15 is the surface electrostatic potential of FSQ-2, FSQ-3 and FSQ-4.

[0045] Figure 16 5F-ABICA@FSQ-4 model for MD simulation.

[0046] Figure 17 The MSD graphs of 5F-ABICA and WH-018 in FSQ-2, FSQ-3 and FSQ-4, respectively.

[0047] Figure 18 is a representative snapshot of the included distribution.

[0048] Figure 19 Figure 1a shows the diffusion coefficients of 5F-ABICA and JWH-018 in FSQ-2, FSQ-3, and FSQ-4, respectively. Figure 1b shows the diffusion coefficients of JWH-018 in FSQ-2, FSQ-3, and FSQ-4, respectively.

[0049] Figure 20 is the extraction efficiency of SCs by FSQ-4 probe in the presence of pH interference, ion interference and interfering substances.

[0050] Figure 21 Figure 2 shows the effect of SPME conditions on the extraction efficiency of SCs by the FSQ-4 probe. Figure a shows the extraction time, Figure b shows the desorption time, and Figure c shows the desorption solvent. DETAILED DESCRIPTION

[0051] The following is a further description of specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to facilitate understanding of the present invention and does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0052] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0053] The chemical reagents and materials used in the present invention are as follows.

[0054] 2-Hydroxybenzene-1,3,5-triacetaldehyde (SOH), 2,4-dihydroxybenzene-1,3,5-triacetaldehyde (DOH), and 2,4,6-triformylphloroglucinol (Tp) were purchased from Jilin Yanshen Technology Co., Ltd. Zinc trifluoromethanesulfonate (Zn(OTf)2), 1,2-dichlorobenzene (o-DCB), and N,N-dimethylacetamide (DMAc) were purchased from Alfa Aesar Chemical Co., Ltd.

[0055] Diamine (1), whose English name is: 3,4-bis[4-amino-3-(trifluoromethyl)anilino]cyclobut-3-ene-1,2-dione (1), was prepared according to the synthesis method in the supporting information of the literature (Angew. Chem. Int. Ed. 2022, 61, e202206749).

[0056] Acetonitrile (ACN), ethanol (EtOH), tetrahydrofuran (THF), methanol (MeOH), and 2-(trifluoromethyl)-1,4-phenylenediamine were purchased from MacLean Biochemical Technology Co., Ltd. Cyclohexane, acetone, hydrochloric acid, sodium hydroxide, toluene, sodium phosphate dodecanoate (Na2HPO4·12H2O), potassium chloride (KCl), and potassium monobasic phosphate (KH2PO4) were purchased from Guangzhou Chemical Reagent Company.

[0057] Palmitic acid, lauric acid, D-(+)-glucose 3,4-dioxy-3-cyclobutane-1,2-dione, formic acid, glacial acetic acid (HAc), and N-methylpyrrolidone (NMP) were purchased from Aladdin Chemicals Ltd. Bovine serum albumin was purchased from J&K Scientific Ltd.

[0058] Amino acid standards (l-alanine, l-arginine, l-cystine, l-glutamic acid, l-histidine) were purchased from Sigma-Aldrich Co., Ltd. Polydimethylsiloxane (PDMS) was prepared using neutral silicone sealant produced by LESSO.

[0059] Commercial PDMS (100 μm), Polyacrylate (PA, 85 μm), PDMS / diinylbenzene (PDMS / DVB, 65 μm), and DVB / Carboxen / PDMS (DVB / CAR / PDMS, 50 / 30 μm) probes were purchased from Supelco. Stainless steel wire (SS) was purchased from Component Supply.

[0060] The 13 synthetic cannabinoids are NM-2201, 5F-ABICA, 5F-PB-22, MDMB-4en-PINACA, JWH-073, JWH-250, AM-2233, AM-1220, JWH-18, JWH 370, JWH-210, JWH-081, and 5F-MPP-PICA; they were provided by the Guangdong Branch of the National Narcotics Laboratory.

[0061] The experimental instrument used in the present invention is as follows:

[0062] The morphology was observed using a Quanta 200 scanning electron microscope (SEM) from the United States and a JEOL 2010 transmission electron microscope (TEM) from Japan. Thermogravimetric analysis (TGA) was performed using a TG 209 F3 Tarsus thermogravimetric analyzer (Netzsch, Germany). Water contact angle images were obtained using a DSA100 drop shape analyzer (Kruss, Germany). X-ray photoelectron spectroscopy (XPS) spectra were obtained using a Thermo-VG Scientific spectrometer (ESCALAB 250, United States). The details of the crystallography were revealed using an Empyrean powder X-ray diffractometer (PXRD, the Netherlands). The nitrogen adsorption and desorption isotherms at 77 K were measured using an automatic gas adsorption analyzer Autosorb-IQ3 (Quantachrome Instruments, America). The specific surface area and pore size distribution of the material were obtained using the BrunauerEmmettTeller (BET) method and density functional theory (NLDFT) method, respectively. 13 C solid-state NMR spectra were recorded on a Bruker AVANCE NEO 600 spectrometer. Fourier transform infrared (FT-IR) spectra were recorded on a Frontier Optica (PerkinElmer).

[0063] Quantification of target SCs was performed using a Waters Acquity ultra-performance liquid chromatography (UPLC) system (Waters, USA) coupled to an AB Sciex Triple Quad 5500+ triple quadrupole tandem mass spectrometer (ESI source, Applied Biosystems / MDS, USA). Chromatographic separation was performed using a Waters Acquity UPLC BEN C18 column (2.1 mm × 100 mm, 1.7 μm, Waters, USA) with a mobile phase consisting of 0.1% formic acid in water (solvent A) and acetonitrile (ACN, solvent B). The optimized mobile phase gradient and monitored shift of SCs are listed in Table 1. The chromatographic retention times of SCs are shown in Table 2. Detection was performed in positive ion mode. The flow rate was 0.4 mL min -1 The injection volume was 10 μL. The multiple reaction monitoring parameters are listed in Table 3.

[0064] Table 1

[0065] Time(min) <![CDATA[Flowrate(mLmin -1 )]]> Solvent A (%) Solvent B (%) Initial 0.400 95.0 5.0 8.00 0.400 10.0 90.0 9.50 0.400 10.0 90.0 9.60 0.400 95.0 5.0 12.00 0.400 95.0 5.0 17.00 0.400 95.0 5.0

[0066] Table 2

[0067]

[0068] Table 3

[0069]

[0070]

[0071] Example 1 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0072] Diamine (1) (25.8 mg, 0.06 mmol) and Tp (8.41 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 6 mol / L. The reaction temperature was 120 ° C. The reaction time was 3 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, an orange powdery fluorinated amide covalent organic framework material (FSQ-4) was obtained by vacuum drying. PXRD showed that FSQ-4 had a good crystal form.

[0073] Example 2 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0074] Diamine (1) (25.8 mg, 0.06 mmol) and Tp (8.41 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 9 mol / L. The reaction temperature was 120 ° C. The reaction time was 3 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, FSQ-4 was obtained as an orange powder by vacuum drying. PXRD showed that FSQ-4 was partially crystalline.

[0075] Example 3 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0076] Diamine (1) (25.8 mg, 0.06 mmol) and Tp (8.41 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 12 mol / L. The reaction temperature was 120 ° C. The reaction time was 3 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, FSQ-4 was obtained as an orange powder by vacuum drying. PXRD showed that FSQ-4 had a good crystal form.

[0077] Example 4 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0078] Diamine (1) (25.8 mg, 0.06 mmol) and Tp (8.41 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 17.5 mol / L. The reaction temperature was 120 ° C. The reaction time was 3 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, FSQ-4 was obtained as an orange powder by vacuum drying. PXRD showed that FSQ-4 was partially crystalline.

[0079] Example 5 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0080] Diamine (1) (25.8 mg, 0.06 mmol) and Tp (8.41 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 12 mol / L. The reaction temperature was 60 ° C. The reaction time was 22 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, an orange powder was obtained by vacuum drying. PXRD showed that the obtained orange powder was amorphous.

[0081] Example 6 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0082] Diamine (1) (25.8 mg, 0.06 mmol) and Tp (8.41 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 12 mol / L. The reaction temperature was 90 ° C. The reaction time was 22 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, an orange powder was obtained by vacuum drying. PXRD showed that the obtained orange powder was amorphous.

[0083] Example 7 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0084] Diamine (1) (25.8 mg, 0.06 mmol) and Tp (8.41 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 12 mol / L. The reaction temperature was 120 ° C. The reaction time was 22 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, an orange powder was obtained by vacuum drying. PXRD showed that the obtained orange powder was amorphous.

[0085] Example 8 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0086] The difference between this embodiment and embodiment 1 is that the reaction temperature is 115°C.

[0087] Example 9 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0088] The difference between this embodiment and embodiment 1 is that the reaction temperature is 125°C.

[0089] Example 10 Preparation of a Fluorinated Squaramide Covalent Organic Framework Material (FSQ-4)

[0090] The difference between this embodiment and embodiment 1 is that the reaction time is 5 days.

[0091] The FSQ-4 prepared in Examples 8 to 10 had a good crystal form as determined by PXRD.

[0092] Comparative Example 1

[0093] Diamine (1) (25.8 mg, 0.06 mmol) and SOH (7.13 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 6 mol / L. The reaction temperature was 120 ° C. The reaction time was 3 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, FSQ-2 was obtained as a yellow powder by vacuum drying. PXRD showed that FSQ-2 had a good crystal form.

[0094] Comparative Example 2

[0095] Diamine (1) (25.8 mg, 0.06 mmol) and DOH (7.77 mg, 0.04 mmol) were added to a 10 ml high temperature resistant reaction tube. Then o-DCB (1 mL) and DMAc (10 drops, 0.5 ml) were added to the reaction tube and ultrasonicated until uniform. The catalyst was acetic acid solution, the amount of acetic acid solution was 10 drops (0.5 ml), and the acetic acid concentration was 6 mol / L. The reaction temperature was 120 ° C. The reaction time was 3 days. After the reaction was completed, the product was filtered and separated, and then Soxhlet extraction was performed with THF. Finally, FSQ-2 was obtained as a yellow powder by vacuum drying. PXRD showed that FSQ-2 had a good crystal form.

[0096] Figure 1 Schematic diagram of the synthesis of FSQ-2, FSQ-3, and FSQ-4. Table 4 shows the implementation parameters of specific examples of fluorinated squaramide covalent organic framework materials (FSQ-2, FSQ-3, and FSQ-4) prepared in some examples and comparative examples, as well as the changes in the material crystal form measured by PXRD.

[0097] Table 4

[0098]

[0099] Test Example 1 Specific Characterization of Fluorinated Squaramide Covalent Organic Framework Materials

[0100] (1) Simulated structures and corresponding PXRD patterns of FSQ-2, FSQ-3, and FSQ-4

[0101] Figure 2The simulated structures (AA or AB stacking) and corresponding PXRD patterns of FSQ-2, FSQ-3, and FSQ-4 are shown. Figure a shows the simulated structure (AA or AB stacking) and corresponding PXRD pattern of FSQ-2; Figure b shows the simulated structure (AA or AB stacking) and corresponding PXRD pattern of FSQ-3; and Figure c shows the simulated structure (AA or AB stacking) and corresponding PXRD pattern of FSQ-4.

[0102] like Figure 2 As shown in a, the experimental data of FSQ-2 are fitted with the PXRD pattern of the AA stacking model. Figure 1 To. Figure 2 b and Figure 2 As shown in Figure c, the PXRD diffraction peaks of FSQ-3 and FSQ-4 are consistent with the AB stacking model. The PXRD patterns confirm the successful preparation of fluorinated squaramide COFs (FSQ-2, FSQ-3, and FSQ-4).

[0103] (2) FSQ-2, FSQ-3 and FSQ-4 nitrogen adsorption and desorption tests, SEM and TEM tests, and water contact angle tests

[0104] Figure 3 The nitrogen adsorption-desorption isotherms of FSQ-2, FSQ-3 and FSQ-4 were used to further study the porosity of the three COFs. The BET surface areas of FSQ-2, FSQ-3 and FSQ-4 were 834, 596 and 534 m 2 g -1 It is worth noting that, if Figure 4 As shown in the results of density functional theory (DFT), the pore sizes of FSQ-2, FSQ-3, and FSQ-4 shift from mesopores (2.99 nm) to micropores (1.41 nm), which is consistent with the stacking model of the simulated structures. Theoretically, FSQ-4 has more abundant micropores than FSQ-2, which is expected to provide higher adsorption capacity.

[0105] Figure 5 The SEM and TEM images of FSQ-2, FSQ-3, and FSQ-4 show that FSQ-2 and FSQ-3 have spherical morphologies, while FSQ-4 exhibits a unique flocculent appearance.

[0106] Figure 6 The water contact angles of FSQ-2, FSQ-3, and FSQ-4 are shown in Table 1. Thanks to the abundant carbonyl and imino groups, FSQ-Xs exhibit good affinity for water. The water contact angles of FSQ-2, FSQ-3, and FSQ-4 are approximately 66.2°, 70.4°, and 50.1°, respectively.

[0107] (3) TEM-EDS elemental maps, C1s XPS tests, FT-IR tests, and thermogravimetric analysis tests of FSQ-2, FSQ-3, and FSQ-4

[0108] To verify the different functional groups in the three COFs, multiple characterization methods were used. Figure 7 TEM-EDS elemental maps of FSQ-2, FSQ-3, and FSQ-4. TEM-EDS elemental maps further confirm the successful preparation of fluorinated squaramide COFs and the presence of different elements.

[0109] Figure 8 The following are the C1s XPS spectra and FT-IR spectra of FSQ-2, FSQ-3 and FSQ-4. Figure a is the C1s XPS spectrum of FSQ-2, FSQ-3 and FSQ-4; Figures b, c and d are the FT-IR spectra of FSQ-2, FSQ-3 and FSQ-4 respectively. Figure a shows that the representative peaks of the XPS spectrum at 292.4, 288.5 and 286.2 eV identify the presence of -CF3, C=O and CN respectively. It is worth noting that the proportion of C=O and CN in FSQ-2, FSQ-3 and FSQ-4 gradually increases, indicating that hydrogen bond donors (-NH-) and hydrogen bond acceptors (C=O) dominate in FSQ-4. Figures bd show that FSQ-Xs at 1642 cm -1 The shoulder peak at 1578cm -1 The two peaks are caused by C=O stretching and C=C stretching, respectively.

[0110] Figure 9 These are the thermogravimetric analysis curves of FSQ-2, FSQ-3, and FSQ-4. Figure 9 The thermogravimetric analysis curves verified that FSQ-2, FSQ-3 and FSQ-4 had good thermal stability (up to 340°C).

[0111] Test Example 2 Adsorption Test of Fluorinated Squaramide Covalent Organic Framework Material

[0112] The physical properties of the 13 SCs used in this test example are shown in Table 5 below.

[0113] Table 5

[0114]

[0115]

[0116]

[0117] a) Statistics are from ChemSpider (http: / / www.chemspider.com / ) and ChemAxon (https: / / chemaxon.com / ).

[0118] (1) Preparation of FSQ-2, FSQ-3, and FSQ-4 probes

[0119] The three prepared COFs were fabricated into SPME probes by gluing. The stainless steel wire was cut into approximately 3.5 cm segments and ultrasonically cleaned in acetone, ethanol, and ultrapure water for 10 minutes. Approximately 1.0 g of polydimethylsiloxane (PDMS) was dispersed in a sample tube with 2.0 mL of cyclohexane and ultrasonically dissolved to obtain a viscous solution. The pretreated stainless steel wire was immersed in the viscous solution and adhered to a thin layer (thickness approximately 0.13 μm, volume approximately 2.06 × 10 6 μm 3 ) of PDMS. A stainless steel wire coated with PDMS was then spin-coated in the FSQ-4 powder to create a layer of material. The resulting coating was cured at 80°C for 30 minutes, and the bonding process was repeated twice, resulting in a uniform FSQ-4 SPME probe (thickness approximately 47-61 μm, volume approximately 1.46 × 10 9 ~1.92×10 9 μm 3 FSQ-2 and FSQ-3 SPME probes were also prepared using the same method. All probes were shaken in methanol (20 ml) for 30 minutes before use. Figure 10 The SEM images of FSQ-2, FSQ-3 and FSQ-4 SPME probes are shown in Figure 2. Figure 10 As shown, the SEM images of the custom probes indicate that uniform coatings were obtained for the three probes.

[0120] As shown in Table 5, most SCs are relatively hydrophilic compounds with low logP values ​​(logP < 7). Therefore, the extraction efficiency of SCs using the FSQ-2, FSQ-3, and FSQ-4 probes in deionized water was evaluated by direct immersion SPME coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS / MS).

[0121] (2) Comparison of the enrichment performance of FSQ-2, FSQ-3, and FSQ-4 probes with various commercial SPME probes for SCs

[0122] First, the enrichment performance of the FSQ-4 probe for SCs was compared with various commercial SPME probes. Commercial polydimethylsiloxane / divinylbenzene (PDMS / DVB) and polyacrylate (PA) fibers were selected due to their high affinity for polar compounds. Commercial PDMS probes have been shown to be effective in enriching non-polar compounds. Additionally, DVB / CAR / PDMS probes were selected for their advantages in extracting aromatic compounds.

[0123] Figure 11 Comparison of the enrichment factors of SCs using commercial PA, PDMS, DVB / CAR / PDMS, DVB / PDMS, FSQ-2, FSQ-3, and FSQ-4 probes. The results show that the enrichment factors (EFs) of the FSQ-4 probe for the 13 SCs ranged from 732 to 3784, demonstrating its excellent extraction ability. Notably, the FSQ-4 probe's extraction efficiency for SCs was 5.6-2245.5 times, 1.7-296.1 times, 2.2-222.4 times, and 1.2-117.9 times that of commercial PA, PDMS / DVB, PDMS, and DVB / CAR / PDMS fibers, respectively. The excellent performance of the FSQ-4 probe demonstrates that the constructed micropores can be used to extract target analytes with diverse physicochemical properties. Furthermore, the extraction efficiency of the FSQ-4 probe was 1.1-2.8 times that of the FSQ-2 probe and 1.4-3.3 times that of the FSQ-3 probe. Strong evidence suggests that, in addition to the fluorine-philic fragment (-CF3), abundant electron-rich groups (C=O) contribute to improving the affinity of the FSQ-4 probe for SCs.

[0124] (3) Binding of FSQ-4 to AM-2233

[0125] In order to reveal the potential extraction mechanism of SCs by FSQ-4, TEM-EDS and XPS analysis were performed after SCs were extracted by FSQ-4. Figure 12 As shown, after extraction of AM-2233, the distribution of iodine (the characteristic element of AM-2233) in the TEM-EDS spectrum of FSQ-4 is consistent with that of the skeleton elements of FSQ-4 ( Figure 12 a). In addition, we also observed the changes in the binding energy of XPS after FSQ-4 extraction of SCs ( Figure 12 be). The representative peak of CI (C1s) was observed in the XPS spectrum. Obviously, the CI bond binding energy corresponds to 620.7 eV (I 3d 5 / 2 ) and 632.3eV(I 3d 3 / 2 ), further confirming the extraction of AM-2233 by FSQ-4.

[0126] (4) Interaction between SCs and FSQ-4 and surface electrostatic potential

[0127] Theoretical calculations are also very important for exploring the interaction between SCs and FSQ-4. Figure 13 is the molecular size of the target SCs. Figure 13 As shown, the molecular sizes of the 13 SCs range from 1.31 to 1.69 nm, which is well matched to the pore size of FSQ-4. Therefore, FSQ-4 is expected to achieve efficient and structure-guided extraction of SCs.

[0128] Subsequently, the surface electrostatic potentials of 13 SCs were simulated. Figure 14 is the surface electrostatic potential of SCs. Figure 14 As shown, SCs are a class of compounds with electron-deficient regions (alkane side chains and aromatic rings) and a prominent positive electrostatic potential region. In addition, the surface electrostatic potentials of FSQ-2, FSQ-3, and FSQ-4 were calculated.

[0129] Figure 15 is the surface electrostatic potential of FSQ-2, FSQ-3 and FSQ-4. Figure 15 As shown in Figure 2, with the increase of hydroxyl (-OH) groups in the aldehyde precursor, more electron-rich carbonyl groups (C=O) appear on the COF backbone. Due to the significant electronegativity of oxygen atoms, the local electron density of FSQ-4 is significantly higher than that of FSQ-2 and FSQ-3. Therefore, SCs can be effectively recognized by non-covalent interactions such as hydrogen bonds.

[0130] (5) Molecular dynamics (MD) simulation of the extraction process of SCs and FSQ-4

[0131] To gain a more intuitive understanding of the extraction mechanism, molecular dynamics (MD) simulations were performed on the extraction of SCs by three COFs, and their diffusion properties were studied. Considering the different structures of the target SCs, two SCs, one containing fluorine (5F-ABICA, 1.32 nm) and one without fluorine (JWH-018, 1.66 nm), were selected as representatives.

[0132] Figure 16 5F-ABICA@FSQ-4 model for MD simulation. Figure 17 The MSD diagrams of 5F-ABICA and WH-018 in FSQ-2, FSQ-3 and FSQ-4 respectively. Figure 16 and 17 As shown, among the three COFs, the mean square displacement (MSD) of 5F-ABICA and JWH-018 increased over time, with the two target analytes increasing the fastest in FSQ-4 ( Figure 17In addition, the diffusion coefficients (D) of 5F-ABICA and JWH-018 in FSQ-4 are larger than those in FSQ-2 and FSQ-3 during the entire simulation, which means that the two target analytes diffuse faster in the FSQ-4 system (e.g. Figure 19 The higher local electron density in the FSQ-4 framework promotes the analyte mobility and improves pore utilization, further confirming the key role of carbonyl groups and micropores in the adsorption process.

[0133] The changes in molecular conformation during the adsorption process of MD simulation are also important information for understanding the extraction mechanism. Figure 18 is a representative snapshot of the included distribution. Figure 18 As shown, 5F-ABICA and JWH-018 exhibit distinct movement patterns within the pores of FSQ-4, with both tending to be located near trifluoromethyl and carbonyl groups. The close proximity of the trifluoromethyl and carbonyl groups of FSQ-4 to the hydrogen atoms of 5F-ABICA and JWH-018 indicates strong non-covalent interactions between FSQ-4 and the two analytes, such as hydrogen bonding and hydrophobic interactions. These universal interactions enable FSQ-4 to efficiently extract a wide range of SCs with diverse properties, demonstrating broad-spectrum and high-efficiency extraction capabilities.

[0134] In summary, the abundant trifluoromethyl and carbonyl groups as well as the matching micropores constructed on FSQ-4 played a crucial role in the extraction process of SCs.

[0135] Test Example 3: Effect of Complex Matrix on FSQ-4 Probe Extraction Efficiency

[0136] In SPME, the selectivity of the coating is crucial, as it can help to achieve the direct extraction of target analytes from real samples without pretreatment (such as pH adjustment). According to the pKa value, the ionization of some SCs is affected by pH conditions (Table 5). When the pH value of the solution varies greatly, the theoretical ratio of unionized and ionized analytes varies significantly. In addition, the concentrations of various interfering substances in real samples are even higher than those of the target analytes, resulting in competitive adsorption. In order to evaluate the effect of the matrix on the extraction, the FSQ-4 probe was used to extract the target analytes from pH (3-9), salt solution (10 mmol L -1 ), humic acid solution (20 mg L -1 SCs were extracted from a mixture of 1% SCs and 1% SCs ...

[0137] Figure 20 is the extraction efficiency of SCs by FSQ-4 probe in the presence of pH interference, ion interference and interfering substances. Figure 20The extraction efficiency of the FSQ-4 probe in the composite matrix was consistent with that of the control, demonstrating its excellent selectivity and anti-interference capabilities. This is likely due to the strong affinity of FSQ-4 for SCs and the size exclusion effect of the micropores. Therefore, the newly developed FSQ-4 probe has great potential for directly extracting SCs from real water samples without pretreatment, while also improving analytical efficiency by reducing sample pretreatment time.

[0138] The parameters affecting the extraction efficiency of the customized FSQ-4 probe were optimized, including extraction time, desorption time, and desorption solvent.

[0139] like Figure 21 As shown in Figure 6, after optimization, the optimal parameters for SCs extraction using FSQ-4 fiber were: extraction time 40 min, desorption time 15 min, and methanol as desorption solvent. Table 6 shows the methodological evaluation of SCs using the FSQ-4 SPME probe coupled with UPLC-MS / MS. As shown in Table 6, under the optimal conditions, the FSQ-4 probe coupled with UPLC-MS / MS achieved excellent analytical performance. Table 7 shows the LODs (ng LODs) of this method compared with other methods reported in the literature. -1 ) comparison. As shown in Table 7, the high enrichment factors (EFs) of the FSQ-4 probe for all target SCs resulted in extremely low limits of detection (LODs). The LODs of this method for all 13 SCs were all below 0.11 ng L -1 , which is much lower than that of most reported works (Table 7). In addition, the wide linear range and satisfactory reproducibility (single and multi-injection) ensure the practicality of the developed method (Table 6), indicating that this method has great application potential in the ultratrace analysis of SCs in actual wastewater samples.

[0140] Table 6

[0141]

[0142] Table 7

[0143]

[0144]

[0145] Municipal wastewater from sewage treatment plants is an economical and readily available source of real-time epidemiological information. This method was used to evaluate the recovery of wastewater samples from three cities in southern China. Because the customized FSQ-4 probe can extract SCs with robustness, extraction was performed directly in wastewater samples without further pretreatment. To verify accuracy, a concentration of 100 ng L was used. -1 , 200ng L -1 and 500ng L -1Table 8 shows the recoveries of SCs in wastewater samples. As shown in Table 8, the recoveries of the 13 SCs ranged from 80.5% to 113.9%, demonstrating the reliability of this method.

[0146] Table 8

[0147]

[0148] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. It is apparent to those skilled in the art that various changes, modifications, substitutions, and variations of these embodiments may be made without departing from the principles and spirit of the present invention, and the changes still fall within the scope of protection of the present invention.

Claims

1. A fluorinated squaramide covalent organic framework material, characterized in that: The fluorinated amide covalent organic framework material has a structure as shown in formula (I):

2. The method for preparing the fluorinated squaramide covalent organic framework material according to claim 1, characterized in that: Diamine (1), 2,4,6-triformylphloroglucinol and a reaction solvent are uniformly mixed, an acid solution is added, and the mixture is reacted at 115 to 125° C. for 3 to 5 days, and the fluorinated amide covalent organic framework material is obtained after post-treatment. The reaction solvent is 1,2-dichlorobenzene and N,N-dimethylacetamide; the concentration of the acid solution is 6 to 17.5 mol / L; the molar ratio of Diamine (1) to 2,4,6-triformylphloroglucinol is 3:2; and the reaction formula is as follows:

3. The preparation method according to claim 2, characterized in that The acid solution is acetic acid solution.

4. The preparation method according to claim 2 or 3, characterized in that The reaction temperature is 120° C.; the concentration of the acid solution is 11 to 13 mol / L.

5. The preparation method according to claim 2, characterized in that: The volume mass ratio of 1,2-dichlorobenzene to Diamine (1) is (0.03-0.05):1 mL / mg; the volume mass ratio of N,N-dimethylacetamide to Diamine (1) is (0.01-0.03):1 mL / mg.

6. Use of the fluorinated squaramide covalent organic framework material according to claim 1 as an adsorbent in the preparation of solid phase microextraction coatings, in the preparation of solid phase microextraction probes, in solid phase microextraction of synthetic cannabinoids, or in the detection of synthetic cannabinoids.

7. A solid phase microextraction coating, characterized in that The solid phase microextraction coating comprises the fluorinated squaramide covalent organic framework material according to claim 1 and a binder.

8. The solid phase microextraction coating according to claim 7, characterized in that: The volume ratio of the fluorinated squaramide covalent organic framework material to the binder is (237-332):

1.

9. A solid phase microextraction probe, characterized in that: It comprises a carrier and the solid phase microextraction coating according to any one of claims 7 to 8.

10. Use of the solid phase microextraction coating according to any one of claims 7 to 8 or the solid phase microextraction probe according to claim 9 in solid phase microextraction of synthetic cannabinoids or in the detection of synthetic cannabinoids.

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