A novel magnetic pillar[5]arene porous polymer BrBP[5]-MNP, its preparation method and application

Abstract

The present invention belongs to the field of materials technology, and particularly relates to the synthesis of a novel magnetic pillar [5] arene porous polymer (BrBP[5]-MNP) and the construction of a new method of magnetic solid-phase extraction-assisted high performance liquid chromatography-tandem mass spectrometry based on the BrBP[5]-MNP. The BrBP[5]-MNP of the present invention takes Fe3O4 as the core, and a pillar [5] arene porous polymer BrBP[5] is coated on the outside of the Fe3O4 nanoparticles. The BrBP[5] is prepared by the cross-linking reaction of bromoethoxy pillar [5] arene and 4,4'-dichloromethyl biphenyl. The BrBP[5]-MNP of the present invention not only has excellent adsorption performance for long-chain PFCs with C8-C 14 but also has good adsorption effects on PFCAs (C6-C7) and PFSAs (C4-C7) with smaller molecular sizes. The new method of magnetic solid-phase extraction-assisted high performance liquid chromatography-tandem mass spectrometry of the present invention can simultaneously perform quantitative analysis on 11 kinds of PFCs, and can be used for the detection of PFCs in actual water samples such as river water, lake water, rainwater, and complex biological matrix samples such as mouse liver, which is of great significance for accurately evaluating their environmental exposure levels and health risks.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and particularly relates to the synthesis of a novel magnetic pillar[5]arene porous polymer (BrBP[5]-MNP) and the construction of a new method of magnetic solid-phase extraction assisted high performance liquid chromatography-tandem mass spectrometry (BrBP[5]-MNP MSPE-HPLC-MS / MS) based on BrBP[5]-MNP, and is applied to the detection of perfluorinated compounds (PFCs) in environmental water samples and biological matrix samples. Background Art

[0002] Perfluorinated compounds (PFCs) belong to a class of synthetic organic compounds. The high bond energy of the C-F bond makes PFCs have excellent chemical stability, so they are widely used in various consumer products and industrial production. At present, PFCs have been widely detected in various complex matrices such as indoor dust, surface water, soil and organisms. These compounds can cause multiple toxic effects on organisms through direct contact and transmission in the food chain, including hepatotoxicity, reproductive toxicity and carcinogenicity, etc., which have attracted widespread attention globally. With the restricted production and use of PFOA, PFOS and long-chain PFCs, the global manufacturing industry is gradually shifting from long-chain PFCs to short-chain PFCs, indicating that short-chain PFCs may have a greater impact in the future. Compared with long-chain PFCs, short-chain PFCs have less accumulation and bio-persistence. However, short-chain PFCs have stronger volatility, which makes them easier to be transported over long distances through the atmosphere. At present, the treatment methods and relevant regulations for short-chain PFCs have been ignored. In environmental and biological samples, PFCs usually exist at extremely low levels, and at the same time, they are accompanied by complex and variable matrix effects, which makes their detection and analysis complicated and challenging. Traditional detection methods often have difficulty in accurately and reliably determining their contents. Therefore, sample pretreatment is particularly important. By pretreatment, trace PFCs can be effectively enriched, the influence of interfering substances can be reduced, and the sensitivity and accuracy of the detection method can be improved. Traditional pretreatment techniques have some disadvantages that cannot be ignored: liquid-liquid extraction involves multiple complex steps, and the operation process is relatively cumbersome; in the recovery and regeneration of organic solvents, a large amount of energy and time are often consumed, and improper treatment may also cause environmental pollution; at the same time, emulsification or layering sometimes occurs during the liquid-liquid extraction process, resulting in difficulty in separating the target substance from the solvent. Solid-liquid extraction also has disadvantages such as large solvent consumption, high mass transfer resistance, complex operation conditions and high cost.

[0003] Magnetic solid-phase extraction (MSPE) is based on the theory of liquid-solid chromatography, using magnetic or magnetizable materials as adsorbents to adsorb target substances from solutions. During the magnetic solid-phase extraction process, after adsorption reaches equilibrium, an external magnetic field can be used to quickly and effectively separate the magnetic adsorption material from the solution. Then, a desorbing solution is used to elute the target compound, which is concentrated by nitrogen blowing and then detected. MSPE not only exhibits excellent extraction ability and extraction efficiency, but also can use a small amount of adsorbent in a short time to achieve the extraction of trace compounds. Magnetic solid-phase extraction has the advantages of rapid separation, simple operation, less solvent consumption, and high extraction efficiency, and can be used for the analysis and detection of trace PFCs in complex matrices.

[0004] To quickly and accurately detect PFCs in environmental samples and achieve effective enrichment, a variety of new adsorbents have been developed. High-efficiency adsorbents show good selective adsorption ability for PFCs, and can specifically extract target pollutants from complex environmental matrices, thus improving the enrichment efficiency and analysis accuracy. Traditional adsorbents such as carbon nanotubes, activated carbon, and graphene oxide have limitations, such as difficult separation and high regeneration costs. There is still a need to continuously design and synthesize new adsorbent materials and develop highly sensitive and selective methods to detect and remove PFCs in the environment.

[0005] In 2008, Japanese chemist Ogoshi et al. successfully synthesized a columnar macrocyclic oligomer with a symmetric structure and para-bridged phenol groups for the first time - pillar[5]arene, which has greater development potential than traditional macrocyclic compounds. Compared with crown ethers and calixarenes, pillararenes have higher symmetry and rigidity, and can selectively bind to guests. Compared with cyclodextrins and cucurbiturils, it is easier to selectively functionalize at one or two specific positions, thereby changing the host-guest binding characteristics. As a new type of columnar host molecule, pillar[n]arene (P[n]A) shows broad application prospects in the fields of adsorption and separation by virtue of its unique highly symmetric rigid structure, electron-rich cavity, and easy modification characteristics. Its rich host-guest properties enable P[n]A to achieve efficient complexation with various guest molecules, thus becoming a powerful tool in the fields of molecular recognition, adsorption separation, etc. At the same time, the easy modification of P[n]A also provides great convenience for the construction of new materials such as porous polymers.

[0006] The main analytical techniques for PFCs include liquid chromatography-tandem mass spectrometry (LC-MS / MS), gas chromatography-tandem mass spectrometry (GC-MS / MS), and surface-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF-MS), etc. LC-MS / MS has become the main technical means for determining trace pollutants in environmental samples due to its high performance, high selectivity, and high sensitivity. Summary of the Invention

[0007] To solve the problem that it is difficult to accurately and reliably determine the content of PFCs by traditional detection methods, in the present invention, bromoethoxycalix[5]arene is cross-linked with 4,4'-dichloromethylbiphenyl (BCMBP) through Friedel-Crafts alkylation reaction to generate calix[5]arene porous polymer (BrBP[5]). Fe3O4 nanoparticles are added for magnetization treatment to prepare a novel magnetic calix[5]arene porous polymer (BrBP[5]-MNP), and a magnetic solid-phase extraction-assisted high-performance liquid chromatography-tandem mass spectrometry method (BrBP[5]-MNP MSPE-HPLC-MS / MS) based on this magnetic calix[5]arene porous polymer is constructed to detect PFCs in complex matrix samples. This method not only has a significant adsorption effect on long-chain PFCs, but also has good adsorption performance for PFCAs (C6-C7) and PFSAs (C4-C7) with smaller molecular sizes, and has been successfully applied to the detection of 11 PFCs in mouse liver samples and environmental water samples, providing new ideas and technical means for enriching PFCs.

[0008] To achieve the above object, the present invention provides a magnetic calix[5]arene porous polymer BrBP[5]-MNP, wherein the BrBP[5]-MNP takes Fe3O4 as the core, and the calix[5]arene porous polymer BrBP[5] is coated on the outside of the Fe3O4 nanoparticles. The structural formula of the BrBP[5] is as follows:

[0009]

[0010] The present invention also provides a preparation method of the BrBP[5]-MNP, including the following steps:

[0011] (1) Prepare 1,4-bis(2-bromoethoxy)benzene

[0012] Under the condition of an ice-water bath at 0 °C, hydroquinone dihydroxyethyl ether and triphenylphosphine are added to anhydrous acetonitrile, and then carbon tetrabromide is slowly added under nitrogen protection. Then, the reaction system is restored to room temperature, and the mixture is stirred at room temperature for 3-6 h until the solution becomes clear and transparent. After the reaction is completed, cold water is added to quench the reaction. The product is purified and dried to obtain 1,4-bis(2-bromoethoxy)benzene.

[0013] (2) Prepare calix[5]arene

[0014] Paraformaldehyde is added to the anhydrous 1,2-dichloroethane solution of 1,4-bis(2-bromoethoxy)benzene. Subsequently, boron trifluoride diethyl etherate (BF3·O(C2H5)2) is added, and the mixture is stirred at room temperature for 4-8 h. After the reaction is completed, cold water is added to quench the reaction. The product is purified and dried to obtain calix[5]arene.

[0015] (3) Prepare Fe3O4 nanoparticles

[0016] Dissolve FeCl3·6H2O and sodium acetate in ethylene glycol. Transfer the obtained homogeneous yellow solution into a polytetrafluoroethylene reaction kettle, seal it and heat to 200 °C. After reacting for 8 - 12 h, cool it to room temperature. Wash and dry the product to obtain Fe3O4 nanoparticles.

[0017] (4) Preparation of BrBP[5]-MNP

[0018] Add Fe3O4 nanoparticles into dichloromethane, ultrasonically disperse Fe3O4 uniformly, then add p - cyclophane[5] and biphenyl dichlorobenzyl (BCMBP), continue ultrasonic treatment to dissolve them, and then slowly add anhydrous ferric chloride under a nitrogen atmosphere. Condense and reflux the reaction mixture at 50 - 100 °C with stirring for 24 - 72 h (preferably condense and reflux at 80 °C with stirring for 48 h). After the reaction is completed, cool it to room temperature, filter, collect the solid, wash and dry it to obtain BrBP[5]-MNP.

[0019] Preferably, in step (1), the molar ratio of hydroquinone di - hydroxyethyl ether to triphenylphosphine is 1:(2 - 3), and the molar ratio of triphenylphosphine to carbon tetrabromide is 1:1; optimally, the molar ratio of hydroquinone di - hydroxyethyl ether, triphenylphosphine to carbon tetrabromide is 5:12:12.

[0020] Preferably, in step (2), the molar ratio of 1,4 - bis(2 - bromoethoxy)benzene, paraformaldehyde to BF3·O(C2H5)2 is 1:(0.5 - 3):(0.5 - 1.5); optimally, the molar ratio of 1,4 - bis(2 - bromoethoxy)benzene, paraformaldehyde to BF3·O(C2H5)2 is 1:1:1.

[0021] Preferably, in step (3), the molar ratio of FeCl3·6H2O to sodium acetate is 1:(1 - 6), and the dosage ratio of FeCl3·6H2O to ethylene glycol is 20 mmol:(50 - 150) mL; optimally, the molar ratio of FeCl3·6H2O to sodium acetate is 1:4, and the dosage ratio of FeCl3·6H2O to ethylene glycol is 20 mmol:100 mL.

[0022] Preferably, in step (4), the dosage ratio of Fe3O4 to dichloromethane is 10 mg:1 mL, and the molar ratio of p - cyclophane[5], biphenyl dichlorobenzyl to ferric chloride is 1:(4 - 12):(20 - 50); optimally, the molar ratio of p - cyclophane[5], biphenyl dichlorobenzyl to ferric chloride is 1:8:25.

[0023] The present invention also provides a method for detecting the content of PFCs by magnetic solid - phase extraction - assisted high - performance liquid chromatography - tandem mass spectrometry based on the above - mentioned BrBP[5]-MNP:

[0024] (1) Chromatographic conditions

[0025] Chromatographic column: C18 column;

[0026] Mobile phase A: 5 mmol / L ammonium acetate aqueous solution, mobile phase B: acetonitrile;

[0027] Flow rate: 0.4 mL / min;

[0028] Column temperature: 40 °C;

[0029] Gradient elution conditions:

[0030]

[0031]

[0032] (2) Mass spectrometry conditions

[0033] An electrospray ionization source (ESI) was used for ionization in the negative ion mode, and multiple reaction monitoring (MRM) was established to analyze each PFC; nebulizing gas flow rate: 3 L / min, heating gas flow rate: 10 L / min, drying gas flow rate: 10 L / min, interface temperature: 300 °C, DL temperature: 250 °C, heating block temperature: 400 °C, and the residence time for each MRM was 12 ms.

[0034] (3) Magnetic solid phase extraction

[0035] After mixing BrBP[5]-MNP with the sample solution, vortex for 2 - 15 min (preferably 8 min) to allow BrBP[5]-MNP to fully adsorb PFCs. After separating BrBP[5]-MNP from the solution with an external magnet, wash BrBP[5]-MNP with pure water to remove unadsorbed PFCs on the surface. Add desorbing solution methanol to BrBP[5]-MNP and vortex for 3 - 15 min (preferably 5 min) to desorb the PFCs adsorbed by BrBP[5]-MNP. After separating BrBP[5]-MNP and the solution with a magnet, take a certain amount of the solution, concentrate it to dryness, then redissolve it with methanol, and take the redissolved solution for HPLC-MS / MS detection.

[0036] The dosage ratio of the adsorbent BrBP[5]-MNP to the desorbing solution methanol is (5 - 20) mg : (3 - 13) mL, and the preferred dosage ratio is 12 mg : 5 mL.

[0037] Preferably, when taking the redissolved solution for HPLC-MS / MS detection, internal standard method is used for quantification, with 13 C8-PFOA and 13 C8-PFOS as internal standards.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] 1. The present invention crosslinks pillar[5]arene with 4,4'-dichloromethylbiphenyl. The resulting polymer has both the highly symmetric columnar structure, electron-rich cavity, and rich host-guest chemical properties of pillar[5]arene, and the rigid structure of BCMBP, further enhancing the stability and porosity of the polymer.

[0040] 2. The present invention combines magnetic nanoparticles with pillar[5]arene polymer for the first time to prepare a magnetic adsorbent, which not only has excellent adsorption performance for long-chain PFCs with C8-C 14 but also has good adsorption effects on PFCAs (C6-C7) and PFSAs (C4-C7) with smaller molecular sizes, and its adsorption recovery rate is above 80%.

[0041] 3. The magnetic adsorbent of the present invention has a simple preparation process, low cost, ideal adsorption effect, is easy to be effectively separated from the system after adsorption, can be recycled, and is suitable for industrial production.

[0042] 4. The present invention constructs a new method of magnetic solid-phase extraction-assisted high performance liquid chromatography-tandem mass spectrometry, which can simultaneously perform quantitative analysis on 11 kinds of PFCs, and can be used for the detection of PFCs in actual water samples such as lake water and rainwater, as well as complex biological matrices such as mouse liver. It is of great significance for accurately evaluating their environmental exposure levels and health risks. Description of the Drawings

[0043] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of pillar[5]arene in Example 1;

[0044] Figure 2 is the nuclear magnetic resonance carbon spectrum of pillar[5]arene in Example 1;

[0045] Figure 3 is the infrared spectrum of pillar[5]arene, BrBP[5], and BrBP[5]-MNP in Example 1;

[0046] Figure 4 In, A and B are field emission scanning electron microscope images of Fe3O4 nanoparticles with scales of 2μm and 1μm respectively, and C and D are field emission scanning electron microscope images of BrBP[5]-MNP with scales of 1μm and 0.5μm respectively;

[0047] Figure 5In Figure A is the transmission electron microscopy image of Fe3O4 nanoparticles with a scale bar of 0.5 μm, Figure B is the transmission electron microscopy image of BrBP[5] with a scale bar of 0.5 μm, and Figures C and D are the transmission electron microscopy images of BrBP[5]-MNP with a scale bar of 200 nm;

[0048] Figure 6 is the nitrogen adsorption-desorption isotherm and pore size distribution diagram of BrBP[5]-MNP in Example 1;

[0049] Figure 7 is the hysteresis loop curve diagram of Fe3O4 and BrBP[5]-MNP in Example 1;

[0050] Figure 8 is the water contact angle diagram of Fe3O4 and BrBP[5]-MNP in Example 1;

[0051] Figure 9 is the recovery rate diagram of BrBP[5]-MNP after adsorbing 13 PFCs in Example 2;

[0052] Figure 10 is the chromatogram of the mixed standard products of 11 PFCs and two isotope internal standards in Example 2;

[0053] Figure 11 is the full scan diagram of 11 PFCs and two isotope internal standards in the negative ion mode in Example 2. Detailed implementation manners

[0054] Below, the applicant will elaborate on the technical solution of the present invention in combination with specific embodiments. However, it should be understood that the following embodiments are only used to illustrate the present invention and not to limit the scope claimed in the claims of the present invention. The experimental methods used in the following embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0055] The information of the PFCs standard products and some reagents used in the following embodiments is shown in Table 1 below:

[0056] Table 1:

[0057]

[0058]

[0059] Example 1: Preparation and characterization of magnetic column [5] arene porous polymer

[0060]

[0061] A preparation method of a magnetic pillar [5] arene porous polymer BrBP [5] - MNP, comprising the following steps:

[0062] (1) Preparation of 1,4 - bis(2 - bromoethoxy)benzene

[0063] Under the condition of an ice - water bath at 0 °C, 10.0 g of hydroquinone dihydroxyethyl ether and 31.5 g of triphenylphosphine (PPh3) are added to 300 mL of anhydrous acetonitrile, and then 39.8 g of carbon tetrabromide (CBr4) is slowly added under nitrogen protection. The ice bath is removed, and the reaction system is restored to room temperature (room temperature in this application refers to 25 °C). Stir at room temperature for 4 h until the solution is clear and transparent. After the reaction is completed, an appropriate amount of cold water (ultrapure water at room temperature, the same below) is added to the reaction mixture to quench the reaction. Filter, collect the solid, wash it with methanol / water (60:40, v / v), and then dry it in vacuo at 40 °C for 24 h to obtain white flaky solid of 1,4 - bis(2 - bromoethoxy)benzene with a yield of 85%.

[0064] (2) Preparation of pillar [5] arene

[0065] 0.349 g of paraformaldehyde (in this application, the molecular weight of paraformaldehyde is calculated as 30.03) is added to a solution of 1,4 - bis(2 - bromoethoxy)benzene (3.37 g) in anhydrous 1,2 - dichloroethane (200 mL). Subsequently, 1.63 g of BF3·O(C2H5)2 is added, and the mixture is stirred at room temperature for 6 h. Monitor the reaction process by thin - layer chromatography. After the reaction is completed, quench it with (2×100 mL) cold water. Extract with dichloromethane solution saturated with sodium chloride, dry the organic phase over anhydrous Na2SO4, concentrate under reduced pressure, purify by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 1:1, v / v), and finally dry it in vacuo at 40 °C for 24 h to obtain white powder of pillar [5] arene with a yield of 41% in this step.

[0066] (3) Preparation of BrBP[5]

[0067] In a 50 - mL round - bottom flask, add pillar [5] arene (0.168 g, 0.1 mmol) and 4,4'-dichloromethylbiphenyl (0.2 g, 0.8 mmol), then add 10 mL of dichloromethane and stir until fully dissolved. Slowly add anhydrous ferric chloride (0.405 g, 2.5 mmol) under a nitrogen atmosphere. Place the reaction mixture in an 80 °C oil bath for reflux stirring for 48 h. After the reaction is completed, cool to room temperature and filter. Wash the filter cake alternately with ultrapure water and methanol, three times each, and dry it in vacuo at 60 °C for 24 h to obtain brown powder BrBP[5] with a yield of 60% in this step.

[0068] (4) Preparation of Fe3O4 nanoparticles

[0069] FeCl3·6H2O (5.40 g, 20 mmol) was added to a three-necked flask containing 100 mL of ethylene glycol. After ultrasonic dispersion for 20 min, sodium acetate (6.50 g, 80 mmol) was added, and the mixture was mechanically stirred at room temperature for 30 min. The resulting homogeneous yellow solution was transferred to a polytetrafluoroethylene reaction kettle, sealed, and placed in a high temperature of 200 °C for reaction for 10 h. Then it was cooled to room temperature, and under the action of an external magnetic field, it was washed alternately with ethanol and deionized water, 5 times for each. After washing, the black product was dried in a vacuum drying oven at 25 °C for 12 h to obtain Fe3O4 nanoparticles.

[0070] (5) Preparation of BrBP[5]-MNP

[0071] Fe3O4 nanoparticles (100 mg) were added to a 50 mL round-bottom flask. After adding 10 mL of dichloromethane and ultrasonic dispersion for 20 min, when Fe3O4 was uniformly dispersed in dichloromethane, pillar[5]arene (0.168 g, 0.1 mmol) and BCMBP (0.2 g, 0.8 mmol) were added, and ultrasonic dispersion was continued for 20 min. Subsequently, anhydrous ferric chloride (0.405 g, 2.5 mmol) was slowly added under a nitrogen atmosphere. The reaction mixture was heated to 80 °C and stirred under reflux for 48 h. After the reaction was completed, it was cooled to room temperature and filtered. The filter cake was washed alternately with ultrapure water and absolute ethanol, 3 times for each, and dried in a vacuum at 60 °C for 24 h to obtain a black-brown powder BrBP[5]-MNP, and the yield of this step was 62%.

[0072] The BrBP[5] and BrBP[5]-MNP prepared in this example were characterized, and the results are as follows:

[0073] (1) NMR analysis

[0074] In this invention, an AVANCE III nuclear magnetic resonance spectrometer of Bruker BioSpin Corporation, Switzerland, was used to analyze the structure of the pillar[5]arene prepared in the above step (2), and its H spectrum and C spectrum are as Figure 1 、 2 shown.

[0075] (2) Fourier transform infrared spectroscopy (FT-IR)

[0076] In this invention, a NEXUS 470 infrared spectrometer of Niolet Company, USA, with the instrument model of Nexus470, was used to characterize the characteristic functional groups of pillar[5]arene, BrBP[5] and BrBP[5]-MNP. Potassium bromide was used as the substrate for the tablet pressing method test to obtain the infrared spectrum data of the samples. The test wavelength range was 4000 - 500 cm -1 ,and the results are asFigure 3 All three substances contain 1631cm -1 The C=C stretching vibration peak of aromatic carbon, column [5] aromatic hydrocarbons, BrBP [5] at 1205 cm -1 The peaks at 619 cm-1 are the stretching vibration peaks of the COC of aromatic ethers and aliphatic ethers, and the peaks at 619 cm-1 of BrBP[5]-MNP are -1 The peak at is the stretching vibration peak of the Fe-O bond, among which the appearance of the Fe-O stretching vibration peak of BrBP[5]-MNP indicates the successful synthesis of the material.

[0077] (3) Field emission scanning electron microscopy (SEM)

[0078] The present invention uses a field emission scanning electron microscope (model SU8010) produced by Japan HITACHI Company to conduct a preliminary analysis of the size and morphology of the synthesized material. The operation process is as follows: Fe3O4 / BrBP[5]-MNP powder is evenly adhered to the sample stage with conductive glue. The size and morphology of the material can be observed by electron microscopy. The results are as follows: Figure 4 shown. Figure 4 Figures A and B show the SEM images of Fe3O4 nanoparticles with a scale of 2μm and 1μm, respectively. It can be clearly seen from the figure that the Fe3O4 nanoparticles are spherical in shape with uniform size and good dispersion. Figures C and D show the SEM images of BrBP[5]-MNPs with a scale of 1μm and 0.5μm. It can be observed from the figure that the whole still maintains a spherical shape, but the surface is smooth and coated with an organic layer. The Fe3O4 nanoparticles are wrapped inside by BrBP[5], indicating that BrBP[5] and Fe3O4 nanoparticles are successfully modified.

[0079] (4) Transmission Scanning Electron Microscope (TEM)

[0080] The morphology of BrBP[5] and BrBP[5]-MNP was further characterized using a TALOS F200X transmission electron microscope from Thermo Fisher Scientific, USA. The material samples were ground and ultrasonically dispersed on a copper mesh with anhydrous ethanol. After the ethanol evaporated, the test was performed. The results are shown in Figure 2. Figure 5 shown. Figure 5 A in the figure shows a TEM image of Fe3O4 nanoparticles with a scale of 0.5 μm. It can be seen from the figure that each Fe3O4 nanoparticle has a clear spherical outline, a smooth surface and uniform size. Figure 5In Figure B is the TEM image of BrBP[5] with a scale bar of 0.5 μm. It can be seen from the figure that BrBP[5] presents a unique "branched" morphology. Smaller nanoparticles or nanoclusters are attached to these pillar arenes with different sizes. These nanoclusters are crosslinking agent BCMBP, and they are densely distributed on the pillar arenes after polymerization. Figure 5 In Figures C and D are the TEM images of BrBP[5]-MNP with a scale bar of 200 nm. It can be seen from the figure that the surface of Fe3O4 nanoparticles is coated with an organic layer of BrBP[5], and the result is consistent with that of the scanning electron microscope.

[0081] (5) Nitrogen physical adsorption and desorption

[0082] The nitrogen adsorption-desorption instrument produced by Micromeritics Corporation of the United States, with the instrument model of ASAP 2020, was used in this invention to characterize the pore structure information such as the pore size and specific surface area of BrBP[5]-MNP. The operation process is as follows: The N2 adsorption and desorption experiment was carried out at 77K, and the BET (Brunauer-Emmett-Teller) method and the Barrett-Joyner-Halenda (BJH) model were used to calculate the specific surface area and pore size of BrBP[5]-MNP. The nitrogen adsorption-desorption isotherm and pore size distribution diagram of BrBP[5]-MNP are as Figure 6 shown. It can be seen from the figure that the adsorption and desorption curves do not completely coincide, presenting an obvious hysteresis phenomenon, with the appearance of a hysteresis loop. The characteristics of the adsorption isotherm are consistent with the H1 type in Type IV. And there is an unclosed phenomenon in the curve. It may be that during the desorption process, the pore structure of the material changed or collapsed, resulting in the failure of the curve to close. On the other hand, too high a micropore ratio may also cause the hysteresis effect during the desorption process, thus triggering the unclosure of the curve. Using the BJH model, the specific surface area of BrBP[5]-MNP was calculated to be 572.87 m 2 / g, and the average pore size was 7.27 nm. It is fully confirmed that BrBP[5]-MNP is a material with mesoporous characteristics, and its higher specific surface area and pore size can provide more adsorption sites for the adsorption of PFCs.

[0083] (6) Hysteresis loop analysis (VSM)

[0084] The vibration sample magnetometer of model 7074 produced by Lake Shore Company of the United States was used to measure the saturation magnetization values of two materials, Fe3O4 nanoparticles and BrBP[5]-MNP, to comprehensively evaluate their magnetization performance. The hysteresis loop curves of Fe3O4 and BrBP[5]-MNP are as Figure 7As shown, it can be seen from the figure that the saturation magnetization value of Fe3O4 is 45.0 emu / g, and the saturation magnetization value of BrBP[5]-MNP is 9.12 emu / g. Compared with Fe3O4, the magnetization value decreases, indicating that the magnetization value will decrease after Fe3O4 is successfully coated with BrBP[5]-MNP. However, BrBP[5]-MNP still has magnetism and can quickly separate the material from the solution through an external magnetic field in a short time, improving the adsorption efficiency.

[0085] (7) Water contact angle analysis (CA)

[0086] In this invention, the OCA20 water contact angle analyzer produced by Dataphysics Company of Germany was used to test the hydrophilicity and hydrophobicity of the synthesized materials. The operation process is as follows: Weigh an appropriate amount of Fe3O4 nanoparticles or BrBP[5]-MNP and press them into a disc-shaped thin slice. Drop water on the surface of the material and measure the angle between the water droplet and the material surface. The results are as Figure 8 shown. The water contact angle of Fe3O4 is 94.9°, and the water contact angle of BrBP[5]-MNP is 140.5°. After BrBP[5]-MNP is magnetized, the water contact angle becomes larger, making it a hydrophobic material, indicating that the material can adsorb PFCs through hydrophobic interaction.

[0087] Example 2: Investigation of the magnetic solid-phase extraction assisted high performance liquid chromatography-tandem mass spectrometry method based on BrBP[5]-MNP

[0088] Chromatographic conditions:

[0089] Chromatographic column: Waters ACQUITY UPLC C18 column (1.7 μm, 2.1×100 mm);

[0090] Mobile phase A: 5 mmol / L ammonium acetate aqueous solution; Mobile phase B: acetonitrile;

[0091] Flow rate: 0.4 mL / min; Column temperature: 40 °C;

[0092] Gradient elution conditions:

[0093] Time (min) Mobile phase A (%) Mobile phase B (%) 0-1 90 10 1-5 10 90 5-8 10 90 8-10 90 10

[0094] Mass spectrometry conditions:

[0095] The high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-8050) produced by Shimadzu of Japan was used for electrospray ionization (ESI). The mass spectrometry parameters were: nebulizing gas flow rate: 3 L / min, heating gas flow rate: 10 L / min, drying gas flow rate: 10 L / min, interface temperature: 300 °C, DL temperature: 250 °C, heating block temperature: 400 °C, and the dwell time for each MRM was 12 ms.

[0096] First, in the negative ion mode, perform a full scan on the 13 PFCs standards and 2 internal standards shown in Table 2 to determine the precursor ions. Secondly, set multiple fragmentation voltages in combination with the found precursor ions, obtain the corresponding fragmentation voltages through product ion scanning, and select the one with the largest abundance as the quantitative ion and the one with the second largest abundance as the qualitative ion according to the magnitude of the fragment ion abundances to obtain the parent-daughter ion pairs corresponding to 15 substances. Finally, optimize the collision energy based on the determined parent-daughter ion pairs and overall optimize the instrument parameters in MS and MS / MS to establish a multiple reaction monitoring mode method (MRM). The MRM analysis parameters of the optimized 13 PFCs and two isotope internal standards are shown in Table 2:

[0097] Table 2: Mass spectrometry parameters of 13 PFCs and two isotope internal standards

[0098]

[0099] 1. Adsorption effect study

[0100] Prepare standard stock solutions: Weigh 10 mg of each of the 13 PFCs standards and dissolve them in 10 mL of chromatographic grade acetonitrile (hereinafter, the acetonitrile used for preparing standard solutions is all chromatographic grade) to prepare standard stock solutions with a concentration of 1 mg / mL, and store them in a refrigerator at 4°C.

[0101] 0.1 ng / mL PFCs mixed standard solution: Take 50 μL of each of the 1 mg / mL standard stock solutions of the 13 PFCs, mix them, add 350 μL of acetonitrile to dilute to a 50 μg / mL mixed standard solution, and then dilute the 50 μg / mL mixed standard solution with acetonitrile to a 0.1 ng / mL mixed standard solution.

[0102] Prepare standard internal standard solutions: Select 13 C8-PFOA and 13 C8-PFOS as internal standard substances, dissolve them with acetonitrile respectively to prepare solutions with a concentration of 50 μg / mL, and store them in a refrigerator at 4°C.

[0103] 10 ng / mL internal standard mixed solution: Take 200 μL of each of the 50 μg / mL 13 C8-PFOA and 13 C8-PFOS solutions, mix them, add 600 μL of acetonitrile to dilute to a 10 μg / mL internal standard mixed solution, and then dilute the 10 μg / mL internal standard mixed solution with acetonitrile to a 10 ng / mL internal standard mixed solution.

[0104] Standard curve preparation: Accurately pipette the above 50 μg / mL mixed standard solution, and use acetonitrile to prepare a series of mixed standard solutions with concentrations of 0.01 ng / mL, 0.02 ng / mL, 0.05 ng / mL, 0.1 ng / mL, 0.2 ng / mL, 0.5 ng / mL, 1 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, 20 ng / mL, 50 ng / mL, and 100 ng / mL. Centrifuge for 3 min, respectively take 90 μL of the supernatant and add 10 μL of the internal standard mixed solution with a concentration of 10 ng / mL ( 13 C-PFOA and 13 C-PFOS). Vortex and mix well, centrifuge for 3 min, take 70 μL into the injection vial, and directly inject it into HPLC-MS / MS with an injection volume of 5 μL. Each variable is measured in parallel three times. Using the concentration of each compound in the series of mixed standard solutions as the abscissa (X), and the ratio of the peak area of each compound to the corresponding internal standard (the internal standard for perfluorocarboxylic acids is 13 C8-PFOA, and the internal standard for perfluorosulfonic acids is 13 C8-PFOS) as the ordinate (Y) to plot the standard curve.

[0105] Using BrBP[5]-MNP as the magnetic solid-phase extraction adsorbent, conduct the adsorption-desorption experiment on PFCs. The specific steps are as follows:

[0106] Place 10 mg of the BrBP[5]-MNP adsorbent obtained in Example 1 into a 50 mL centrifuge tube, and add 10 mL of a 13-PFCs mixed standard solution with a concentration of 0.1 ng / mL. Perform vortex operation on the vortex mixer for 5 min to ensure that the BrBP[5]-MNP adsorbent fully and selectively adsorbs PFCs. Use an external magnet to quickly and effectively separate the BrBP[5]-MNP adsorbent from the solution, then add 5 mL of pure water to elute the PFCs not adsorbed on the surface of the BrBP[5]-MNP adsorbent, and use the magnet to separate the adsorbent from the aqueous solution again. Add 5 mL of methanol as the eluent, vortex for 5 min to desorb the PFCs adsorbed by BrBP[5]-MNP. Attach the magnet to the outside of the centrifuge tube to adsorb the material, let it stand until it clarifies, take 4 mL of the supernatant and place it in a new centrifuge tube, use a nitrogen blower to dry it, and add 200 μL of chromatographic-grade methanol to redissolve the PFCs. Centrifuge the re-dissolved solution for 3 min, then take 90 μL, add 10 μL of the 13 C8-PFOA and 13 C8-PFOS internal standard mixed solution. After mixing evenly, take 70 μL for HPLC-MS / MS detection with a mass spectrometry injection volume of 5 μL, and measure in parallel three times.

[0107] Calculate the ratio of the peak area of perfluorocarboxylic acid or perfluorosulfonic acid to its corresponding internal standard respectively, substitute it into the above standard curve equation, and calculate the actual sample concentration. Recovery rate (%) = actual sample concentration / theoretical calculated concentration × 100%, where the theoretical calculated concentration is the concentration of each compound in the solution after reconstitution assuming 100% adsorption by the adsorbent material (calculated to be 4 ng / mL).

[0108] The recovery results of 13 PFCs adsorbed by BrBP[5]-MNP are as Figure 9 shown. The experimental results show that BrBP[5]-MNP has an adsorption effect on 13 PFCs, has the potential to be used as an adsorbent material for magnetic solid-phase extraction, and the adsorption recovery rate of long-chain PFCs is greater than that of short-chain PFCs. The main reasons may be as follows: First, BrBP[5]-MNP is a porous polymer material obtained by the Friedel-Crafts alkylation crosslinking of pillar[5]arene and biphenyldichlorobenzyl, and a large number of pores are generated by introducing a rigid structure. From the nitrogen adsorption and desorption characterization of this material, the specific surface area of BrBP[5]-MNP is 572.87 m 2 / g. The ultra-high specific surface area can provide sufficient adsorption sites to adsorb PFCs molecules of different sizes. Second, from the results of the water contact angle test, the BrBP[5]-MNP material has good hydrophobic properties, enabling it to effectively adsorb PFCs through hydrophobic interactions. As the carbon chain length of PFCs increases, its hydrophobicity also increases, resulting in an enhanced interaction force with the hydrophobic material. Therefore, compared with short-chain PFCs, the adsorption effect of long-chain PFCs on the BrBP[5]-MNP material is significantly better. Finally, the BrBP[5]-MNP material contains a rich cavity structure and excellent host-guest properties. PFCs can selectively enter the cavity of the BrBP[5]-MNP material through host-guest interactions, enabling PFCs to selectively enter the cavity according to their molecular size and shape. Long-chain PFCs (such as C 8- C 14 ) usually show a stronger adsorption effect in host-guest interactions. This is mainly due to the strong hydrophobicity of long-chain PFCs and the size matching with the cavity of the BrBP[5]-MNP material, making them have a higher affinity in the selective adsorption process.

[0109] 2. Optimization of adsorption-desorption conditions

[0110] To optimize the adsorption and desorption conditions, a single-factor experimental design was adopted. The experiments mainly focused on the following key factors: adsorbent dosage, adsorption time, desorbent type, desorbent volume, and desorption time. To ensure the accuracy and reliability of the experimental results, three parallel experiments were conducted for each variable. Deeply explore the adsorption performance of the BrBP[5]-MNP adsorbent for PFCs in order to achieve the best adsorption effect.

[0111] Adsorbent dosage: First, the effect of the mass of the BrBP[5]-MNP adsorbent on the adsorption of PFCs was investigated. In a series of 50 mL centrifuge tubes, 5 mg, 8 mg, 10 mg, 12 mg, 15 mg, and 20 mg of the BrBP[5]-MNP material were accurately added. Then, 10 mL of a mixed standard solution of 13 PFCs with a concentration of 0.1 ng / mL was added to each centrifuge tube. The adsorption-desorption experiment was carried out according to the process in 1. The results showed that when the mass of the BrBP[5]-MNP adsorbent was 12 mg, its adsorption performance was the most excellent, showing advantages over the adsorption effects under the other five different mass conditions. Considering both the adsorption effect and economy, 12 mg of the BrBP[5]-MNP material was finally determined as the optimal adsorbent dosage for subsequent experimental studies.

[0112] Adsorption time: The adsorption process is essentially a dynamic equilibrium process, and the adsorption time is one of the key variables determining the adsorption efficiency of the material, so it is necessary to optimize the adsorption time. The adsorption time was changed, and the adsorption was carried out for 2 min, 5 min, 8 min, 10 min, 12 min, and 15 min respectively, and the rest of the experimental process was carried out according to 1. The results showed that the change in the adsorption time had no particularly obvious effect on the adsorption effect of the BrBP[5]-MNP material. When the adsorption time was 8 min, the adsorption recovery rates of PFOA and PFOS were higher than those under other time conditions. Therefore, 8 min was selected as the optimal adsorption time for the BrBP[5]-MNP material for the next step of optimization.

[0113] Desorbing solution type: On the basis of the optimized conditions, six desorbing solutions with different polarities were selected for optimization. The adsorption-desorption experiment was carried out according to the process in 1, and 5 mL of n-hexane, dichloromethane, ethyl acetate, acetone, methanol, and acetonitrile were added respectively during elution. The results showed that the non-polar solvent n-hexane had almost no elution effect on the 13 PFCs, and the recovery rate was less than 10%. There were also differences in the elution effects of the other 5 organic solvents with different polarities on the PFCs. When methanol was used as the desorbing solution, the recovery rates of the 13 PFCs were the highest. Because methanol, as a polar solvent, has strong elution ability and can interact with polar PFCs to elute them from the BrBP[5]-MNP material. Therefore, methanol was selected as the optimal desorbing solution to explore the subsequent conditions.

[0114] Volume of desorbing solution: There is a close relationship between the change in the volume of the desorbing solution and the adsorption recovery rate. By reasonably controlling the volume of the desorbing solution, the desorption efficiency can be effectively improved, thereby increasing the recovery rate of the target substance. Therefore, the dosage of the eluent was optimized. According to the adsorption-desorption process in 1, 3 mL, 5 mL, 7 mL, 9 mL, 11 mL, and 13 mL of chromatographic-grade methanol were added respectively during elution. The results showed that when 5 mL of the eluent was used, the overall adsorption effect of PFCs showed relatively good performance. For short-chain PFCs, when the eluent volume was 5 mL, the adsorption recovery rates of these compounds were significantly higher than those under other volume conditions. There was not much change in other compounds. A 5-mL eluent volume could provide a better balance point, especially for the adsorption recovery rate of short-chain PFCs. Therefore, 5 mL was determined as the optimal eluent volume.

[0115] Desorption time: Desorption time is also one of the important factors affecting the adsorption efficiency. Different adsorbents have different adsorption rates. To improve the adsorption efficiency, an appropriate desorption time needs to be controlled. According to the adsorption-desorption process in 1, vortex elution was carried out for 3 min, 5 min, 8 min, 10 min, 12 min, and 15 min respectively. The results showed that changing the desorption time had little effect on the recovery rate of PFCs. This might be because the influence of the volume and composition of the eluent on the adsorption recovery rate was greater than that of the elution time, and the BrBP[5]-MNP material could elute PFCs in a short time. When the desorption time was 5 min, the adsorption recovery rates of 8 kinds of PFCs were higher than those under other time conditions. Therefore, 5 min was selected as the optimal desorption time.

[0116] 3. Methodological verification

[0117] 1 mg / mL standard stock solution of PFCs and 10 ng / mL internal standard mixed solution: Directly use the solutions prepared in 1.

[0118] 1) System suitability

[0119] Take 50 μL each of the 1 mg / mL standard stock solutions of 11 kinds of PFCs (specific categories are shown in Figure 10 ) and mix them, then add 450 μL of acetonitrile to dilute to a 50 μg / mL mixed standard solution. Then dilute the 50 μg / mL mixed standard solution to a 0.1 ng / mL mixed standard solution with acetonitrile. Take 90 μL of the well-mixed 0.1 ng / mL mixed standard solution and add 10 μL of the 10 ng / mL internal standard mixed solution. After mixing evenly, take 70 μL and put it into an injection vial, and detect the chromatogram of the standard product on a high-performance liquid chromatography-mass spectrometry instrument according to the chromatographic conditions in this example.

[0120] Figure 10It is the chromatogram of a mixed standard of 11 PFCs and two isotope internal standards. Under the optimized chromatographic conditions, the 11 PFCs can be eluted successively within 10 min, presenting sharp and non-tailing peak shapes, indicating that there is no interference from matrix effects during the analysis process, and a strong response signal is obtained, demonstrating the high efficiency and good separation performance of the method.

[0121] Take 90 μL of the above-mentioned 0.1 ng / mL mixed standard solution, add 10 μL of the 10 ng / mL internal standard mixed solution, mix well, then take 70 μL and put it into an injection vial, and obtain a full-scan mass spectrum by Q3 full-scan detection on a high-performance liquid chromatography-mass spectrometry instrument according to the mass spectrometry conditions in this example.

[0122] Figure 11 It is the full-scan map of 11 PFCs and two isotope internal standards in the negative ion mode. Since the functional groups of PFCs are carboxyl or sulfonic acid groups, PFCs are more likely to be deprotonated to form [M-H] - molecular ion peaks. It can be seen from the figure that the [M-H] - ions of 11 compounds.

[0123] 2) Linearity, quantification limit, detection limit

[0124] Under the optimized magnetic solid-phase extraction conditions, the performance of the BrBP[5]-MNP MSPE-HPLC-MS / MS analysis method was comprehensively evaluated. The linear range, correlation coefficient (R 2 ), detection limit (LOD, S / N≥3), and quantification limit (LOQ, S / N≥10) of this method were investigated to comprehensively evaluate the accuracy, reliability, and sensitivity of the method. The specific operation process is as follows:

[0125] Precisely measure 1 mL of each 1 mg / mL standard stock solution of 11 PFCs (specific categories are shown in Table 3), place them in the same 100 mL volumetric flask, dilute to the mark with HPLC-grade acetonitrile, shake well to obtain a 10 μg / mL mixed standard solution. Dilute the 10 μg / mL mixed standard solution with HPLC-grade acetonitrile to a series of mixed standard solutions with concentrations of 0.01 ng / mL, 0.02 ng / mL, 0.05 ng / mL, 0.1 ng / mL, 0.2 ng / mL, 0.5 ng / mL, 1 ng / mL, 2 ng / mL, 5 ng / mL, 10 ng / mL, 20 ng / mL, 50 ng / mL, and 100 ng / mL. Centrifuge for 3 min, respectively take 90 μL of the supernatant and add 10 μL of the internal standard mixed solution with a concentration of 10 ng / mL, vortex and mix well, centrifuge for 3 min, and take 70 μL of the centrifuged solution into the injection vial. In addition, prepare two blank variables with HPLC-grade acetonitrile, a single blank sample (adding internal standard to the acetonitrile solution), and a double blank sample (neither analyte nor internal standard, pure acetonitrile). Inject directly with HPLC-MS / MS, the injection volume is 5 μL, and each variable is measured in parallel three times.

[0126] Using the concentration of each compound in the series of mixed standard solutions as the abscissa (X), and the ratio of the peak area of each compound to the peak area of the corresponding internal standard as the ordinate (Y) to perform weighted linear regression. Define the signal-to-noise ratio S / N≥3 as the limit of detection (LOD), and S / N≥10 as the limit of quantification (LOQ). Calculate the RSD based on the peak area ratios measured three times, and the results are shown in Table 3. For the 11 PFCs, there is a significant linear correlation between the peak area ratio and the concentration within the linear range, and the correlation coefficient R 2 is greater than 0.9968. The limit of detection (signal-to-noise ratio S / N≥3) is 0.8 - 3.0 ng / L, the limit of quantification (S / N≥10) is 2.0 - 10.0 ng / L, and the RSD ranges from 1.1% to 9.4%. The experimental results show that this method not only has high sensitivity but also has good linearity.

[0127] Table 3

[0128]

[0129] Example 3: Detection of PFCs in actual water samples

[0130] The present invention collected and detected water samples from three main lakes in Wuhan City: Nanhu Lake, Tangxun Lake, and East Lake. These water bodies may be affected by urban activities and thus contain different degrees of PFCs pollution. In addition, in order to evaluate the potential impact of atmospheric deposition on urban surface water, the present invention also collected rainwater samples in Wuhan City.

[0131] The collected water samples are stored in clean and dry containers washed with deionized water. Subsequently, the collected water samples are filtered through a 0.22 μm filter membrane to remove suspended particles and other impurities. The filtered water samples are placed in a refrigerator at 4 °C and stored in the dark to prevent contamination or deterioration for subsequent use.

[0132] Using BrBP[5]-MNP as the magnetic solid-phase extraction adsorbent, a BrBP[5]-MNP MSPE-HPLC-MS / MS method was established for the enrichment and detection of PFCs in environmental water samples. The results showed that PFCs were not detected in the South Lake water sample, East Lake water sample, and rainwater sample, but two short-chain PFCs, PFBS and PFHxA, were detected in the Tangxun Lake water sample, with concentrations reaching 415.15 ng / L and 68.09 ng / L, respectively. With the restriction and prohibition of the use of long-chain PFCs in the environment, the use of short-chain PFCs has shown an upward trend, which is clearly reflected in the detection of short-chain PFCs in water environment samples.

[0133] An accuracy experiment was conducted using the Tangxun Lake water sample, and the specific steps are as follows:

[0134] First, the 1 mg / L mixed standard solution (using the 10 μg / mL mixed standard solution under the linear detection in Example 2 and diluting it to 1 mg / L with chromatographic grade acetonitrile) was diluted with the above-mentioned treated Tangxun Lake water sample to prepare three different concentration levels of test solutions: low (20 ng / L), medium (200 ng / L), and high (2000 ng / L). Take 10 mL of the test solution and add it to 12 mg of the BrBP[5]-MNP material obtained in Example 1. Vortex for 8 min on a vortex mixer to allow the material to fully contact with the environmental water sample, then separate the material from the solution under the action of a magnet, and add 5 mL of pure water to wash away the residues and unadsorbed PFCs on the surface of the material. Then add 5 mL of chromatographic grade methanol and vortex for 5 min to desorb the PFCs adsorbed on the material. Take 4 mL of the supernatant under the action of an external magnet and blow it to dry with nitrogen, and then re-dissolve it with 200 μL of methanol. Take 90 μL of the re-dissolved solution, add 10 μL of the internal standard mixed solution of 13 C-PFOA and 13 C-PFOS, vortex and mix well, and then detect according to the chromatographic and mass spectrometric conditions in Example 2. Each concentration is measured in parallel three times.

[0135] The recovery results are shown in Table 4, where the RSD was calculated from the peak area ratios measured three times. After spiking, the average recovery rates for the low, medium, and high concentrations ranged from 82.5 to 103.1%, and the RSD ranged from 0.14 to 11.4%. Based on BrBP[5]-MNP as the adsorbent material, the established BrBP[5]-MNP MSPE-HPLC-MS / MS method demonstrated excellent precision and stability. This method can not only effectively enrich PFCs in complex actual environmental water samples but also accurately analyze them. Its high precision ensures the accuracy and reliability of the experimental results, while its good stability makes the method widely applicable in practical applications.

[0136] Table 4

[0137]

[0138] Example 4: Detection of PFCs in Mouse Liver Tissue Samples

[0139] To study the adsorption effect of BrBP[5]-MNP material on PFCs in different matrices, the present invention explored its adsorption behavior on PFCs in biological matrices. Using BrBP[5]-MNP material as the magnetic solid-phase extraction adsorbent, a BrBP[5]-MNP MSPE-HPLC-MS / MS method was established and applied to the determination of PFCs in liver tissue samples of BALB / c mice.

[0140] In this example, 6-week-old SPF-grade male BALB / c mice purchased from the Experimental Animal Center of Huazhong Agricultural University (license number: SCXK(E)2020-0019) were raised in an SPF-grade barrier laboratory. The experiment was divided into four groups with an experimental period of 42 days. Specifically: The PFOA and PFOS single-exposure groups were respectively gavaged daily with drug doses of 0.5 mg / kg and 0.1 mg / kg (dissolve PFOA / PFOS in a small amount of DMSO first, and then dilute it to an appropriate concentration with pure water for gavage), the PFOA + PS NPs (polystyrene nanoplastics) combined-exposure group was gavaged daily with a drug dose of 0.5 mg / kg PFOA + 2.5 mg / kg PS NPs, and the PFOS + PS NPs combined-exposure group was gavaged daily with a drug dose of 0.1 mg / kg PFOS + 2.5 mg / kg PS NPs (dissolve PS NPs in pure water and dilute it to 50 mg / mL for gavage) to evaluate the accumulation of PFCs in mice under different conditions and their potential effects. After 42 days of exposure, the mice were anesthetized, sacrificed by cervical dislocation, and liver samples were taken from the mice. After weighing, they were rinsed with phosphate-buffered saline (PBS) and stored at -80 °C until analysis.

[0141] Pretreatment of mouse liver: Methyl tert-butyl ether (MTBE) was used to extract PFCs from mouse liver samples to remove complex matrix effects. The specific experimental steps were as follows: 40 mg of liver samples were taken in a 2 mL centrifuge tube, 300 μL of pure water was added to the system, followed by the addition of 200 μL of sodium carbonate buffer solution (0.25 M, pH = 10), 100 μL of tetrabutylammonium hydrogen sulfate (0.5 M) and 500 μL of MTBE. The samples were first vortex-extracted for 20 min, then ultrasonically extracted for 10 min. After centrifugation, the MTBE layer was separated, and the extraction was repeated twice. The extracted MTBE layers were combined, dried with nitrogen, and then redissolved with 100 μL of methanol. Since the contents of PFOA and PFOS in the actual samples were relatively high and could not be directly detected by mass spectrometry, the solution after redissolution needed to be diluted 1000 times with methanol. Then, the PFOA and PFOS in mouse liver were quantitatively analyzed based on the BrBP[5]-MNP MSPE-FPLC-MS / MS method. The specific steps were as follows:

[0142] Mixed standard solution of 1 mg / L PFOA and PFOS: 100 μL of 1 mg / mL standard stock solutions of PFOA and PFOS were accurately measured and placed in the same 100 mL volumetric flask, diluted to the mark with HPLC-grade acetonitrile, and shaken well to obtain.

[0143] Take the solution extracted and diluted from the mouse liver samples above as the solvent, and dilute the mixed standard solution of 1 mg / L PFOA and PFOS to prepare test solutions at three different concentration levels of low (20 ng / L), medium (200 ng / L) and high (2000 ng / L). Take 10 mL of the test solution and add it to 12 mg of the BrBP[5]-MNP material obtained in Example 1. Vortex for 8 min on a vortex mixer to make the material fully contact with the sample solution, then separate the material from the solution under the action of a magnet, add 5 mL of pure water to wash away the residues on the material surface and unadsorbed PFCs. Then add 5 mL of chromatographic-grade methanol and vortex for 5 min to desorb the PFCs adsorbed on the material. Under the action of an external magnet, take 4 mL of the supernatant and blow it to dry with nitrogen, and then redissolve it with 200 μL of methanol. Take 90 μL of the redissolved solution, add 10 μL of the internal standard mixed solution of 13 C-PFOA and 13 C-PFOS, vortex and mix well, and then detect according to the chromatographic and mass spectrometric conditions in Example 2, and measure in parallel three times.

[0144] The detection results are shown in Table 5. The results indicate that PFCs were detected in all four groups of mouse liver samples. The detected concentration in the PFOA single-exposure group was 50.85 ng / mg, in the PFOS single-exposure group was 24.15 ng / mg, in the PFOA + PS NPs co-exposure group was 51.2 ng / mg, and in the PFOS + PS NPs co-exposure group was 32.85 ng / mg. After spiking, the average recovery rates for the low, medium, and high concentrations ranged from 83.9% to 104.4%, and the RSD ranged from 1.8% to 11.5%. This shows that the analytical method established using BrBP[5]-MNP as the adsorbent material has good precision and accuracy, and can effectively adsorb PFCs not only in actual water samples but also in biological matrices.

[0145] Table 5

[0146]

Claims

1. A method for simultaneously detecting the contents of 11 PFCs in a complex matrix, characterized in that: The method is based on BrBP[5]-MNP magnetic solid phase extraction assisted high performance liquid chromatography-tandem mass spectrometry; The 11 kinds of PFCs are: PFBS, PFOS, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, and PFTeDA; The BrBP[5]-MNP has Fe3O4 nanoparticles as the core, and the Fe3O4 nanoparticles are coated with a column[5] aromatic porous polymer BrBP[5]. The structural formula of the BrBP[5] is as follows: (1) Chromatographic conditions Chromatographic column: C18 column; Mobile phase A: 5mmol / L ammonium acetate aqueous solution, mobile phase B: acetonitrile; Flow rate: 0.4 mL / min; Column temperature: 40°C; Gradient elution conditions: (2) Mass spectrometry conditions An electrospray ionization source was used to ionize in negative ion mode, and multiple reaction monitoring mode MRM was established to analyze each PFCs; nebulizer gas flow rate: 3 L / min, heating gas flow rate: 10 L / min, drying gas flow rate: 10 L / min, interface temperature: 300 °C, DL temperature: 250 °C, heating block temperature: 400 °C, and each MRM dwell time was 12 ms; (3) Magnetic solid phase extraction After mixing BrBP[5]-MNP with the sample solution, vortex operation is performed for 2-15 minutes to allow BrBP[5]-MNP to fully adsorb PFCs; after separating BrBP[5]-MNP from the solution with an external magnet, BrBP[5]-MNP is washed with pure water to remove PFCs not adsorbed on the surface; desorption liquid methanol is added to BrBP[5]-MNP, and vortex operation is performed for 3-15 minutes to desorb PFCs adsorbed by BrBP[5]-MNP; after separating BrBP[5]-MNP from the solution with a magnet, a certain amount of solution is taken, concentrated to dryness, and then methanol is added to dissolve it again, and the dissolved solution is taken for HPLC-MS / MS detection; The dosage ratio of the BrBP[5]-MNP to the desorption liquid methanol is (5-20) mg:(3-13) mL.

2. The method according to claim 1, characterized in that: The BrBP[5]-MNP is prepared by the following method: cross-linking bromoethoxy column[5]arene with 4,4'-dichloromethylbiphenyl through Friedel-Crafts alkylation reaction to generate column[5]arene porous polymer BrBP[5], and adding Fe3O4 nanoparticles for magnetization treatment.

3. The method according to claim 2, characterized in that The preparation method of BrBP[5]-MNP specifically comprises the following steps: (1) Preparation of 1,4-bis(2-bromoethoxy)benzene Under the condition of an ice water bath at 0°C, hydroquinone dihydroxyethyl ether and triphenylphosphine are added to anhydrous acetonitrile, and then carbon tetrabromide is slowly added under the protection of nitrogen, and then the reaction system is restored to room temperature, and stirred at room temperature for 3-6 hours until the solution becomes clear and transparent; after the reaction is completed, cold water is added to quench the reaction, and the product is purified and dried to obtain 1,4-bis(2-bromoethoxy)benzene; (2) Preparation of Column [5] Aromatics Add paraformaldehyde to an anhydrous 1,2-dichloroethane solution of 1,4-bis(2-bromoethoxy)benzene, then add boron trifluoride etherate, and stir at room temperature for 4-8 hours; after the reaction is completed, quench the reaction with cold water, purify and dry the product to obtain column [5] aromatics; (3) Preparation of Fe3O4 nanoparticles Dissolve FeCl3·6H2O and sodium acetate in ethylene glycol, transfer the obtained uniform yellow solution into a reaction kettle, seal and heat to 200°C, react for 8-12 hours, and then cool to room temperature; wash and dry the product to obtain Fe3O4 nanoparticles; (4) Preparation of BrBP[5]-MNPs Fe3O4 nanoparticles are added to dichloromethane, and the Fe3O4 is evenly dispersed by ultrasound. Then, column [5] aromatic hydrocarbons and biphenyl dichlorobenzyl are added, and ultrasound is continued to dissolve them. Subsequently, anhydrous ferric chloride is slowly added under a nitrogen atmosphere, and the reaction mixture is condensed and refluxed at 50-100°C with stirring for 24-72 hours. After the reaction is completed, it is cooled to room temperature, filtered, the solid is collected, washed, and dried to obtain BrBP[5]-MNP.

4. The method according to claim 3, characterized in that In step (1), the molar ratio of hydroquinone dihydroxyethyl ether to triphenylphosphine is 1:2-3, and the molar ratio of triphenylphosphine to carbon tetrabromide is 1:

1.

5. The method according to claim 4, characterized in that In step (1), the molar ratio of hydroquinone dihydroxyethyl ether, triphenylphosphine and carbon tetrabromide is 5:12:

12.

6. The method according to claim 3, characterized in that In step (2), the molar ratio of 1,4-bis(2-bromoethoxy)benzene, paraformaldehyde and boron trifluoride etherate is 1:0.5-3:0.5-1.

5.

7. The method according to claim 6, characterized in that In step (2), the molar ratio of 1,4-bis(2-bromoethoxy)benzene, paraformaldehyde and boron trifluoride etherate is 1:1:

1.

8. The method according to claim 3, characterized in that In step (3), the molar ratio of FeCl3·6H2O to sodium acetate is 1:1-6, and the dosage ratio of FeCl3·6H2O to ethylene glycol is 20mmol:(50-150)mL.

9. The method according to claim 8, characterized in that In step (3), the molar ratio of FeCl3·6H2O to sodium acetate is 1:4, and the amount ratio of FeCl3·6H2O to ethylene glycol is 20mmol:100mL.

10. The method according to claim 3, characterized in that In step (4), the dosage ratio of Fe3O4 and dichloromethane is 10 mg:1 mL, and the molar ratio of column [5] aromatic hydrocarbon, biphenyl dichlorobenzyl, and ferric chloride is 1:4-12:20-50.

11. The method according to claim 10, characterized in that In step (4), the molar ratio of column [5] aromatic hydrocarbon, biphenyl dichlorobenzyl and ferric chloride is 1:8:25.

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