A solid phase extraction membrane based on MOF material and a preparation method and application thereof

Abstract

The application discloses a solid-phase extraction membrane based on MOF material and a preparation method and application thereof, and the solid-phase extraction membrane comprises a carrier and an enrichment medium coating loaded on the surface of the carrier; the material of the enrichment medium coating is a defective amino MOF material; the defective amino MOF material is a metal organic framework material prepared by taking zirconium as a metal center, taking dichloroacetic acid as a modulator and reacting with an amino organic ligand; and the carrier is an organic filter membrane. The adsorbent used in the coating of the solid-phase extraction membrane is a defective MOF material prepared by induction of dichloroacetic acid, and the material has the advantages of large adsorption capacity and good chemical stability; the solid-phase membrane coating prepared by taking the material as raw material has the advantages of good water resistance, high enrichment multiple and good reproducibility, and has excellent adsorption effect on bromoacetic acid and iodoacetic acid.

Description

Technical Field

[0001] The present invention relates to the technical field of solid phase extraction, and in particular to a solid phase extraction membrane based on MOF material, and a preparation method and application thereof. Background Art

[0002] Disinfection byproducts (DBPs) are compounds formed during the disinfection process when disinfectants react with organic matter in water. They are commonly found in tap water, swimming pool water, aquaculture water, and aquatic products. Approximately 800 DBPs have been identified, primarily including trihalomethanes (THMs), haloacetic acids (HAAs), halogenated amides, and aromatic DBPs. Haloacetic acid DBPs primarily include chloroacetic acid, dichloroacetic acid, and bromoacetic acid, with concentrations in tap water ranging from ng / L to μg / L. Due to their potential health implications, countries have strict regulations regarding the concentration of haloacetic acid DBPs in drinking water and related samples. Iodoacetic acid is a newly discovered class of DBPs. Although national limits have not yet been established for their concentration, their concentrations are significantly lower than those of more common chlorinated and bromoacetic acid DBPs, and they exhibit greater toxicity. Because brominated and iodoacetic acids exist at trace levels and in complex water matrices, their efficient separation, enrichment, and accurate quantification remain challenging.

[0003] Currently, the main efficient methods for enriching brominated and iodinated acetic acids in drinking water are liquid-liquid extraction (LLE) and solid-phase extraction (SPE). LLE is a classic sample pretreatment method based on the different partition coefficients of analytes between two immiscible solvents. However, it suffers from drawbacks such as cumbersome and time-consuming procedures, high organic solvent consumption, and environmental pollution. SPE utilizes a solid adsorbent to adsorb and separate the target analytes from the sample matrix, which are then removed with an eluent to achieve separation and enrichment. However, the solid-phase extraction process is often accompanied by column clogging and stationary phase loss due to channeling. The concentration of brominated and iodinated acetic acids in raw water samples is generally in the ng / L range, below the detection limit of analytical instruments. Accurate quantification of brominated and iodinated acetic acids by LLE and SPE requires increased sample volume and large amounts of organic solvent to elute the target compounds, resulting in high experimental costs. Membrane solid phase extraction (M-SPE) technology offers strong matrix purification capabilities, large separation capacity, and single-step concentration and purification. This significantly simplifies sample preparation and improves extraction efficiency, making it ideal for the efficient separation and enrichment of trace aromatic DBPs in complex samples. The performance of M-SPE is closely related to the enrichment medium immobilized on the membrane. The key to improving M-SPE efficiency lies in the development of highly efficient separation and enrichment media.

[0004] Metal-organic frameworks (MOFs) have the advantages of high specific surface area, porosity, structural design, and customization diversity, making them excellent separation and enrichment media. However, the application of MOFs in sample preparation also has certain limitations: (1) the metal coordination bond is relatively weak, and the chemical stability of MOF materials is insufficient; (2) the small pore cross-sectional area of ​​MOFs makes it difficult to capture target compounds from water samples. Currently, there is little research on MOFs in the field of membrane solid-phase extraction, and there is no research and development of membrane solid-phase extraction technology for brominated and iodinated acetic acid. Summary of the Invention

[0005] To overcome the problems of the prior art described above, one of the objectives of the present invention is to provide a solid-phase extraction membrane based on MOF materials. A second objective of the present invention is to provide a method for preparing such a solid-phase extraction membrane based on MOF materials. A third objective of the present invention is to provide the use of such a solid-phase extraction membrane based on MOF materials in the detection of disinfection by-products. The solid-phase extraction membrane has high selectivity for brominated and iodinated acetic acid, is suitable for the detection of brominated and iodinated acetic acid over a wide concentration range, and can detect trace amounts of brominated and iodinated acetic acid in tea beverage samples.

[0006] The present application solves the above problems by using MOF material defect engineering. Defects in MOF form larger specific surface area and larger pores, so that solute molecules and target molecules diffuse faster. In addition, the introduction of mesopores can enhance the accessibility of micropores and active adsorption sites, thereby minimizing diffusion barriers. UIO-66-NH2 has very high chemical stability and strong defect tolerance. The preparation of defective UIO-66-NH2 material not only produces more active binding sites, but also has larger pore size and surface area. Using defective UIO-66-NH2 as the enrichment medium coating of the solid-phase extraction membrane has the advantages of good water resistance, high enrichment factor and good reproducibility, and has excellent adsorption effect on bromo and iodo acetic acid disinfection by-products.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0008] The first aspect of the present application provides a solid-phase extraction membrane based on MOF material, which comprises a carrier and an enrichment medium coating loaded on the surface of the carrier.

[0009] The material of the enrichment medium coating is a defective amino MOF material; the defective amino MOF material is a metal organic framework material (defective UIO-66-NH2) prepared by taking zirconium as the metal center, dichloroacetic acid as the modulator, and amino organic ligand;

[0010] The carrier is an organic filter membrane.

[0011] Preferably, the carrier is a nylon filter membrane, a polyvinylidene fluoride filter membrane, or a polytetrafluoroethylene filter membrane.

[0012] Preferably, the particle size of the defective amino MOF material is 50-150 nm. More preferably, the particle size of the defective amino MOF material is 50-100 nm.

[0013] Preferably, the defective amino MOF material is prepared by a preparation method comprising the following steps: reacting zirconium salt, dichloroacetic acid and 2-amino terephthalic acid in an organic solvent to obtain the defective amino MOF material.

[0014] More preferably, the molar ratio of the zirconium salt to dichloroacetic acid is 1:(5-20).

[0015] More preferably, the molar ratio of the zirconium salt to 2-amino terephthalic acid is 1:(0.3-1).

[0016] More preferably, the preparation method further comprises separation, elution, and drying; further preferably, the elution step comprises washing with an N,N-dimethylformamide solution containing hydrochloric acid, and the washing process is carried out at 90-120° C. for 10-13 hours.

[0017] More preferably, the reaction temperature is 100 to 150°C. More preferably, the reaction temperature is 110 to 130°C.

[0018] More preferably, the reaction time is 12 to 48 hours. More preferably, the reaction time is 12 to 36 hours.

[0019] More preferably, the zirconium salt is zirconium chloride or zirconium oxychloride.

[0020] More preferably, the ratio of the zirconium salt to the organic solution is (4-7) mg:1 mL.

[0021] More preferably, the organic solvent is N,N-dimethylformamide solution (DMF).

[0022] The second aspect of the present invention provides a method for preparing the solid phase extraction membrane based on MOF material according to the first aspect, comprising the following steps:

[0023] 1) dispersing the defective amino MOF material in a solvent to prepare a suspension;

[0024] 2) Using an organic filter membrane to filter the suspension, the defective amino MOF material is loaded on the organic filter membrane to form a solid phase extraction membrane coating, thereby preparing the MOF material-based solid phase extraction membrane.

[0025] Preferably, in step 2), the filtration method adopts syringe filter membrane filtration.

[0026] More preferably, the syringe filter filtration step is: injecting a certain amount of suspension into a syringe, connecting the filter head of the organic filter membrane to the liquid outlet of the syringe, pushing the syringe, so that the defective amino MOF material passes through the membrane together with the solvent, wherein the organic solvent flows out through the micropores of the membrane, and the defective amino MOF material is deposited on the membrane to form a uniform layer of membrane, which is then dried to obtain a solid phase extraction membrane based on MOF material.

[0027] Preferably, the solvent is methanol.

[0028] Preferably, the concentration of the suspension is 0.1-10 mg / mL.

[0029] Preferably, the organic filter membrane is a nylon-66 membrane; more preferably, the diameter of the nylon-66 membrane is 13 mm and the pore size is less than 1 μm.

[0030] Preferably, the method further includes a step of activating the solid phase extraction membrane. More preferably, the specific process of activating the solid phase extraction membrane comprises: injecting methanol and water into a needle syringe, manually pushing the syringe to allow the methanol and water to pass through the solid phase extraction membrane coating formed by the defective amino MOF material, and then setting aside.

[0031] The third aspect of the present invention provides the use of the solid phase extraction membrane based on MOF materials described in the first aspect in detecting disinfection by-products.

[0032] Preferably, the disinfection by-products are halogenated acetic acids and their derivatives.

[0033] More preferably, the halogenated acetic acid is diiodoacetic acid (DIAA), bromoacetic acid (BAA), iodoacetic acid (IAA), dibromoacetic acid (DBAA) and bromochloroacetic acid (BCAA).

[0034] More preferably, the haloacetic acid derivatives are bromoacetamide (BAcAm) and dichloroacetamide (DCAcAm).

[0035] Preferably, the extraction conditions of the solid phase extraction membrane based on MOF material for detecting disinfection by-products are as follows: the amount of enrichment medium is 0.8-4.0 mg, the extraction flow rate is 0.5-2.5 mL / min, the desorption solvent is methanol (containing 1-4% formic acid), the desorption solvent volume is 0.5-2.5 mL, the desorption flow rate is 0.1-0.4 mL / min, and the extraction pH is 1.0-5.0. More preferably, the extraction conditions of the solid phase extraction membrane based on MOF material for detecting disinfection by-products are as follows: the amount of enrichment medium is 2.0-4.0 mg, the extraction flow rate is 1.0-2.0 mL / min, the desorption solvent is methanol (containing 2-4% formic acid), the desorption solvent volume is 1.0-2.0 mL, the desorption flow rate is 0.2-0.4 mL / min, and the extraction pH is 1.0-2.0.

[0036] Preferably, the solid phase extraction membrane based on MOF material is used in detecting disinfection by-products in beverage samples.

[0037] More preferably, the beverage sample is pre-treated before testing, specifically: the beverage sample is sonicated, centrifuged to remove precipitates, the supernatant is filtered with an aqueous filter membrane, the pH of the supernatant to be tested is adjusted to 3.0, and placed in a needle syringe.

[0038] Preferably, the method for detecting disinfection by-products in the application is specifically:

[0039] 1) Using a defective MOF membrane to extract working solutions of varying concentrations, three parallel tests were performed at each concentration. UPLC-MS / MS was used to obtain peak areas corresponding to a range of concentrations. The peak areas were plotted as the ordinate to determine the linear range of the defective MOF membrane test.

[0040] 2) Using the defective MOF membrane to extract the test solution, analyzing it using UPLC-MS / MS, substituting the obtained peak area into a linear equation, and measuring the content of bromoacetic acid or iodoacetic acid in the test solution.

[0041] The beneficial effects of the present invention are:

[0042] The present invention provides a solid-phase extraction membrane. The adsorbent used in the solid-phase extraction membrane coating is a defective MOF material induced by dichloroacetic acid. The material has the advantages of large adsorption capacity and good chemical stability. The solid-phase membrane coating prepared with the material as the raw material has good water resistance, high enrichment multiple, and good reproducibility, and has an excellent adsorption effect on brominated and iodinated acetic acid.

[0043] Specifically, compared with the prior art, the present invention has the following advantages:

[0044] The present invention provides a solid-phase extraction membrane. The adsorbent used in the solid-phase extraction membrane coating is a defective MOF material. Dichloroacetic acid is used as a modulator to induce the formation of mesopores in the MOF, further enhancing the medium's ability to enrich brominated and iodinated acetic acids. The synthesized defective MOF material can serve as an enrichment medium to efficiently enrich brominated and iodinated acetic acids. Furthermore, the solid-phase extraction membrane coating made from the defective MOF material is highly selective for enriching brominated and iodinated acetic acids, is simple to prepare, and exhibits excellent chemical stability.

[0045] 2) The present invention prepares a defective MOF solid-phase extraction membrane coating by direct deposition. The preparation steps are simple and do not require complex equipment. The solid-phase extraction membrane coating prepared by the method has good chemical stability, excellent adsorption effect on brominated and iodinated acetic acid, high enrichment multiples and good reproducibility.

[0046] 3) The solid-phase extraction membrane coating prepared by the present invention is used to determine brominated and iodinated acetic acid in tea beverage samples, with advantages such as a good linear range, low detection limit, and high recovery rate. This analytical method enriches brominated and iodinated acetic acid in tea beverage samples through defective MOF materials. It can also be used in conjunction with UPLC-MS / MS to detect brominated and iodinated acetic acid. The signal intensity generated by brominated and iodinated acetic acid shows a good linear relationship with its content, enabling trace detection of halogenated benzoic acid and halogenated benzaldehyde DBPs in tea beverage samples. Compared with existing technologies, its operation is simpler and its detection capability is greatly improved, which has practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the scanning electron microscope image of defective UIO-66-NH2 material;

[0048] Figure 2 Schematic diagram of the preparation process of defective UIO-66-NH2 solid phase extraction membrane;

[0049] Figure 3 Optimize the filler content of defective UIO-66-NH2 solid phase extraction membrane coating;

[0050] Figure 4 Optimize the extraction flow rate of defective UIO-66-NH2 solid phase extraction membrane;

[0051] Figure 5 Optimization of desorption solvent for defective UIO-66-NH2 solid phase extraction membrane;

[0052] Figure 6 Optimization of solvent volume for desorption of defective UIO-66-NH2 solid phase extraction membrane;

[0053] Figure 7 Optimize the desorption flow rate of defective UIO-66-NH2 solid phase extraction membrane;

[0054] Figure 8 Optimize the extraction pH for defective UIO-66-NH2 solid phase extraction membrane;

[0055] Figure 9 To explore the selectivity of defective UIO-66-NH2 adsorbent;

[0056] Figure 10 The linear range of defective UIO-66-NH2 solid phase extraction membrane for diiodoacetic acid detection;

[0057] Figure 11 The linear range of defective UIO-66-NH2 solid phase extraction membrane for bromoacetic acid detection;

[0058] Figure 12 The linear range of defective UIO-66-NH2 solid phase extraction membrane for iodoacetic acid detection;

[0059] Figure 13 The linear range of defective UIO-66-NH2 solid phase extraction membrane for dibromoacetic acid detection;

[0060] Figure 14 The linear range of defective UIO-66-NH2 solid phase extraction membrane for the detection of bromochloroacetic acid;

[0061] Figure 15 Chromatograms of defective UIO-66-NH2 solid phase extraction membrane for green tea sample and spiked sample;

[0062] Figure 16 Chromatogram of black tea sample and spiked sample using defective UIO-66-NH2 solid phase extraction membrane;

[0063] Figure 17 Chromatogram of jasmine tea sample and spiked sample using defective UIO-66-NH2 solid phase extraction membrane. DETAILED DESCRIPTION

[0064] The present application will be further described in details by specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial channels or prepared and isolated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.

[0065] Example 1

[0066] 1. Preparation of defective MOF material

[0067] Accurately weigh 320 mg of zirconium tetrachloride (1.372 mmol) and 0.85 mL of dichloroacetic acid (10.29 mmol) into a 100 mL conical flask, add 60 mL of DMF, and ultrasonicate for 20 min to completely dissolve the reactants. After the solution is uniformly mixed, add 124 mg of 2-amino terephthalic acid (0.686 mmol) to it, and continue to ultrasonicate to completely dissolve. Transfer the above solution to a 100 mL polytetrafluoroethylene liner flask, and then transfer it to a 100 mL reaction kettle, and place it in a blast drying oven for reaction at 120°C for 24 h. After the reaction is completed, naturally cool to room temperature, centrifuge and collect the product. First, wash the product with 30 mL of DMF for 3 times, then disperse the product into 100 mL of DMF containing 0.4 mL of HCl, and stir and reflux at 90°C for 12 h to elute dichloroacetic acid in the material, and repeat this elution step once. Finally, wash the product with DMF and methanol for 3 times respectively, centrifuge to collect the material, and place it in a blast drying oven at 60°C for vacuum drying for 24 h to obtain the defective amino MOF material, which is defective UIO-66-NH2.

[0068] The defective UIO-66-NH2 material obtained by the synthesis method is used to prepare the solid phase extraction membrane coating in the solid phase extraction membrane of the present application.

[0069] The micro-morphology of the prepared defective UIO-66-NH2 material is characterized by scanning electron microscopy, and the scanning electron microscopy image shown in FIG. 1 is obtained. Figure 1 The material has a microcrystalline morphology with a particle size of about 80 nm.

[0070] 2. Preparation of solid phase extraction membrane containing defective MOF coating

[0071] The preparation process of solid phase extraction membrane is as follows Figure 2 As shown, the specific preparation method is carried out according to the following steps:

[0072] (1) The defective MOF powder was stirred and dispersed in methanol to prepare a suspension with a concentration of 1 mg / mL. 3 mL of the suspension was injected into a needle syringe. A nylon-66 membrane filter (13 mm diameter, 0.22 μm pore size) was connected to the syringe outlet. The syringe was manually pushed, allowing the defective MOF to pass through the membrane along with the methanol. The methanol flowed out through the micropores of the membrane, and the defective MOF powder was deposited on the membrane to form a uniform film. The membrane was then dried at room temperature to obtain a solid phase extraction membrane coating.

[0073] (2) Activation of the solid phase extraction membrane coating: 3.0 mL of methanol and 3.0 mL of ultrapure water were respectively injected into a needle syringe, and the syringe was manually pushed to allow the methanol and water to pass through the solid phase extraction membrane coating obtained in step (1) for later use.

[0074] Optimization of operating conditions for solid phase extraction membrane coating

[0075] The operating conditions of solid phase extraction membrane coating made of defective MOF materials when used in membrane solid phase extraction are optimized.

[0076] 1. Chromatographic conditions

[0077] During the experiment, ultra-high pressure liquid chromatography-mass spectrometry (UPLC-MS / MS) was used to characterize the properties of the defective MOF coating prepared in Example 1.

[0078] In LC-MS / MS, an Endeavorsil C18-A column (2.1 mm × 150 mm × 1.8 μm) was used; mobile phase A consisted of 0.1% acetic acid solution; mobile phase B was pure methanol; the injection volume was 10 μL, the flow rate was 0.3 mL / min, and the column temperature was 40°C. A liquid chromatography gradient elution program was used: 0-2.0 min, 10% B; 2.0-5.0 min, 10%-40% B; 5.0-9.0 min, 10% B.

[0079] The extracted disinfection byproducts were diiodoacetic acid (DIAA), bromoacetic acid (BAA), iodoacetic acid (IAA), dibromoacetic acid (DBAA) and bromochloroacetic acid (BCAA).

[0080] 2. Optimization of optimal extraction conditions

[0081] The concentration of analytes in the sample measured by solid phase membrane extraction technology is affected by the amount of enrichment medium, extraction flow rate, desorption solvent type, desorption solvent volume, desorption flow rate, sample pH, etc. Before using the defective MOF coating prepared in Example 1, it is necessary to optimize the optimal extraction conditions of the coating. The experimental results of optimizing the filler amount of the defective UIO-66-NH2 solid phase extraction membrane coating are shown in Figure 2. Figure 3 As shown; the results of the solid phase extraction membrane extraction flow rate optimization experiment are shown Figure 4 The results of the solid phase extraction membrane desorption solvent optimization experiment are shown in Figure 5 As shown; the results of the solid phase extraction membrane desorption solvent volume optimization experiment are shown in Figure 6 As shown; the results of the solid phase extraction membrane desorption flow rate optimization experiment are shown Figure 7 As shown; the results of the solid phase extraction membrane extraction pH optimization experiment are shown Figure 8 As shown in the figure. The optimal extraction conditions of the five DBPs were different. The extraction conditions that achieved the best extraction efficiency for most DBPs were the final optimized conditions: the amount of enrichment medium was 3.0 mg ( Figure 3 ), the extraction flow rate was 1.8 mL / min ( Figure 4 ), the desorption solvent is 2% formic acid methanol ( Figure 5 ), the desorption solvent volume is 2.0 mL ( Figure 6 ), the desorption flow rate was 0.08 mL / min ( Figure 7 ), extraction pH was 3.0( Figure 8 ).

[0082] 3. Selective exploration of defective MOF adsorbents

[0083] The enrichment selectivity of defective MOF was evaluated by comparing the extraction recoveries of 0.25 ng / mL target DBPs and four structural analogs, chloroacetic acid (CAA), chloroacetamide (CAcAm), bromoacetamide (BAcAm) and dichloroacetamide (DCAcAm) under the optimized extraction conditions. Figure 9 It can be seen that the defective MOF can still maintain a good extraction recovery rate for the five target DBPs in the presence of four structural analogs. The results show that the defective MOF has a certain selectivity for halogenated carboxylic acid compounds and can be used to selectively extract compounds with similar chemical structures to halogenated carboxylic acids.

[0084] Application Example 1

[0085] The performance of membrane solid phase extraction coating made of defective MOF materials was characterized.

[0086] 1. Solution preparation

[0087] (1) Preparation of stock solutions of bromoacetic and iodoacetic acid compounds: First, dissolve diiodoacetic acid (DIAA), bromoacetic acid (BAA), iodoacetic acid (IAA), dibromoacetic acid (DBAA), and bromochloroacetic acid (BCAA) in chromatographically pure methanol to prepare initial standard solutions. Then, take a certain amount of the initial standard solutions of the above five compounds and add them to a 20 mL brown volumetric flask with a small amount of chromatographically pure methanol. Dilute with methanol to prepare a stock solution with a concentration of 1000 mg / L, and then store at 4°C until use.

[0088] (2) Preparation of working solution: Prepare a certain amount of stock solution into a 20 mL sample bottle, shake well and set aside. Prepare the working solution immediately before use.

[0089] 2. Under the optimal extraction conditions, the defective MOF membrane was used to extract a series of freshly prepared working solutions of different concentrations. Three groups of solutions were tested in parallel under each concentration condition and analyzed by UPLC-MS / MS to obtain the peak areas corresponding to a series of concentrations. The linear range of the defective MOF membrane test was obtained by plotting the peak areas as the ordinate. Figures 10-14 ).

[0090] The specific results are shown in Table 1. The defective MOF coating has good linearity for the detection of brominated and iodinated acetic acid (R between 0.9990-0.9998), and the detection limit is 5.0-15.0 ng / L.

[0091] Table 1 Linear range, detection limit, quantification limit and reproducibility of defective UIO-66-NH2 membrane

[0092]

[0093] Application Example 2

[0094] In this example, a solid phase extraction membrane made of defective UIO-66-NH2 material was used to determine brominated and iodinated acetic acids in tea beverages, namely DIAA, BAA, IAA, DBAA, and BCAA.

[0095] Green tea, black tea, and jasmine tea samples were purchased from commercial sources and tested for their brominated and iodinated acetic acid content. The brominated and iodinated acetic acids in the treated tea samples were extracted using the defective UIO-66-NH2 membrane prepared in Example 2. The resulting peak areas were substituted into a linear equation to determine the contents of the five brominated and iodinated acetic acids.

[0096] Sample processing: The beverage sample was sonicated for 10 minutes, centrifuged to remove the precipitate, and the supernatant was filtered through a 0.22μm aqueous filter membrane. 20.0mL of the sample was measured, the pH was adjusted to 3.0, and placed in a 20mL needle syringe. The syringe was connected to the defective UIO-66-NH2 extraction membrane prepared in Example 2, fixed on a ten-channel syringe pump, and enriched at a flow rate of 1.8mL / min. After enrichment, the solid phase extraction membrane was eluted with 2.0mL of 2% formic acid in methanol. The eluate was purged with nitrogen to concentrate it to near dryness, dissolved in 0.2mL of 10% methanol in water, and 10μL of the liquid sample was injected and analyzed.

[0097] By adding a certain concentration of mixed standard solution into the beverage sample, the chromatograms of the original green tea sample and the green tea spiked sample were obtained as shown in the figure. Figure 15 As shown, the chromatograms of black tea sample and black tea spiked sample are as follows Figure 16 As shown, the chromatograms of jasmine tea sample and jasmine tea spiked sample are as follows Figure 17 The specific sample detection amounts and spiked recoveries are shown in Tables 2, 3, and 4. The recoveries of the five brominated and iodinated acetic acid compounds ranged from 78.3% to 124%, indicating that this method meets the requirements for trace analysis.

[0098] Table 2 Detection results of defective UIO-66-NH2 extraction membrane for brominated and iodinated acetic acid in green tea

[0099]

[0100] Table 3 Detection results of defective UIO-66-NH2 extraction membrane for brominated and iodinated acetic acid in black tea

[0101]

[0102]

[0103] Table 4 Detection results of defective UIO-66-NH2 extraction membrane for brominated and iodinated acetic acid in jasmine tea

[0104]

[0105] Application Example 3

[0106] Bromoacetic and iodoacetic acids in green tea and black tea samples were detected using the LLE-UPLC-MS / MS method reported in the literature (Simultaneous determination of iodinated haloacetic acids and aromatic iodinated disinfection byproducts in waters with a new SPE-HPLC-MS / MS method) and the analytical method using the solid phase extraction membrane of Example 1 combined with UPLC-MS / MS (denoted as M-SPE-UPLC-MS / MS).

[0107] Sample Preparation: The beverage sample was sonicated for 10 minutes, centrifuged to remove the precipitate, and the supernatant filtered through a 0.22 μm aqueous filter. A 100.0 mL sample was measured and the pH adjusted to 0.5 with sulfuric acid, followed by the addition of 10.0 g of Na₂SO₄. The acidified sample was extracted with 10 mL of methyl tert-butyl ether. After extraction, the organic layer was transferred to a centrifuge tube, and the extract was concentrated to 0.5 mL using nitrogen purge. 1 mL of acetonitrile was added to the concentrate, which was then purged with nitrogen until near dryness. The concentrate was then dissolved in 0.1 mL of 10% methanol in water, and 10 μL of the sample was sampled for analysis. The results are shown in Table 4.

[0108] Table 4 Summary of method comparison results

[0109]

[0110]

[0111] As can be seen from Table 4, the RSD value of SPE-LC-MS / MS is smaller than that of LLE-UPLC-MS / MS, so the precision of the result is higher, indicating that the solid phase extraction membrane of the present invention combined with UPLC-MS / MS can achieve trace detection of halogenated benzoic acid and halogenated benzaldehyde DBPs in tea beverage samples.

[0112] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A solid phase extraction membrane based on MOF material, characterized in that: The solid phase extraction membrane includes a carrier and an enrichment medium coating loaded on the surface of the carrier; The material of the enrichment medium coating is a defective amino MOF material; the defective amino MOF material is a metal organic framework material prepared by reacting zirconium as the metal center, dichloroacetic acid as a modulator, and amino organic ligands; the defective amino MOF material is prepared by a preparation method comprising the following steps: reacting a zirconium salt, dichloroacetic acid, and 2-aminoterephthalic acid in an organic solvent to prepare the defective amino MOF material; the molar ratio of the zirconium salt to the dichloroacetic acid is 1:(5-20); the molar ratio of the zirconium salt to the 2-aminoterephthalic acid is 1:(0.3-1); the preparation method further comprises separating, eluting, and drying the product after the reaction; the elution step comprises washing with an N,N-dimethylformamide solution containing hydrochloric acid, and the washing process is treated at 90-120°C for 10-13 hours; The carrier is an organic filter membrane.

2. The solid phase extraction membrane based on MOF material according to claim 1, characterized in that: The carrier is a nylon filter membrane, a polyvinylidene fluoride filter membrane or a polytetrafluoroethylene filter membrane.

3. The solid phase extraction membrane based on MOF material according to claim 1, characterized in that: The zirconium salt is zirconium chloride or zirconium oxychloride.

4. The solid phase extraction membrane based on MOF material according to claim 1, characterized in that The reaction temperature of the reaction is 100-150°C; And / or, the reaction time of the reaction is 12 to 48 hours.

5. The solid phase extraction membrane based on MOF material according to claim 1, characterized in that: The particle size of the defective amino MOF material is 50-150 nm.

6. The method for preparing a solid phase extraction membrane based on MOF material according to any one of claims 1 to 5, characterized in that: The steps include: 1) dispersing the defective amino MOF material in a solvent to prepare a suspension; 2) Using an organic filter membrane to filter the suspension, the defective amino MOF material is loaded on the organic filter membrane to form a solid phase extraction membrane coating, thereby preparing the MOF material-based solid phase extraction membrane.

7. The method for preparing a solid phase extraction membrane based on MOF material according to claim 6, characterized in that: In step 2), the filtration method adopts syringe filter membrane filtration.

8. Use of the MOF material-based solid phase extraction membrane according to any one of claims 1 to 5 in detecting disinfection by-products.

9. The use of the MOF material-based solid phase extraction membrane in detecting disinfection by-products according to claim 8, characterized in that: The disinfection by-products are halogenated acetic acids and their derivatives.

Images