Functionalized MXene-based material, preparation method and application in separation and enrichment of trace endocrine disrupter

Abstract

The invention relates to a functionalized MXene-based material as well as a preparation method and application of the functionalized MXene-based material in separation and enrichment of trace endocrine disruptors. The preparation method comprises the following steps: dispersing MXene in ethanol and deionized water, adding APTES, stirring, washing, and drying to obtain NH2-MXene; the preparation method comprises the following steps: dissolving TAPB in a solvent, adding benzaldehyde to obtain a solution A, dissolving BTCA in dioxane / mesitylene, adding aniline to obtain a solution B, mixing the solution A and the solution B, adding a catalyst and NH2-MXene, and carrying out ultrasonic treatment, reaction, washing and drying to obtain COF-coated MXene. The COF and MXene composite material is synthesized by a fluorine-free safe method, has a large specific surface area and a porous structure, and can be used for adsorbing and extracting trace BPs in a water sample and an environment. Moreover, the HPLC analysis conditions of the samples are optimized, so that the detection method has the advantages of low cost and high sensitivity.

Description

Technical Field

[0001] The present invention belongs to the field of environmental technology detection, and specifically relates to a functionalized MXene-based material, a preparation method thereof, and an application in the separation and enrichment of trace endocrine disruptors. Background Art

[0002] Environmental endocrine disruptors (EDCs) are common pollutants in the environment that affect the endocrine systems of humans and animals, threaten health, survival, and reproduction. Environmental endocrine disruptors are closely related to human reproductive disorders, developmental disorders, and some cancers, and have a greater impact on the environment. They can disrupt organisms in the environment at extremely low concentrations. These pollutants are present in low concentrations in the environment, and the sensitivity of common current instrumental analysis methods cannot meet the detection requirements. Therefore, sample pretreatment methods are needed to concentrate and enrich the samples. For example, methods such as Soxhlet extraction and liquid-liquid extraction often have disadvantages such as complex operations, long processing cycles, large losses of organic solvents, and low extraction efficiency. In order to achieve more effective concentration and enrichment, in recent years, methods such as solid-phase extraction, solid-phase microextraction, microwave-assisted extraction, accelerated solvent extraction, pre-column derivatization, pre-column enrichment, preconcentration electrophoresis, and sample preconcentration have been widely used in sample preparation. Detection methods for environmental endocrine disruptors include methods such as GC-MS / MS, LC-MS / MS, cytotoxicity detection methods, biological detection methods, hormone level detection methods, receptor binding activity detection methods, PCR, and gene expression analysis. However, large-scale instruments such as GC-MS / MS and LC-MS / MS are not only expensive but also have high operating costs and are not suitable for ordinary laboratories. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems existing in the prior art and provide a solid-phase extraction-HPLC-UV detection method for environmental endocrine disruptors in water samples and foods.

[0004] The specific technical solution adopted by the present invention is as follows: A functionalized MXene-based material, and the preparation method includes the following steps:

[0005] 1) Preparation of NH 2 -MXene: Disperse MXene in ethanol and deionized water, slowly add APTES, stir, wash, and dry to obtain NH 2 -MXene;

[0006] 2) Preparation of COF@MXene: Dissolve TAPB in dioxane / mesitylene, add benzaldehyde to obtain solution A, dissolve BTCA in dioxane / mesitylene, add aniline to obtain solution B, mix solution A and solution B, and add 0.5 mg Sc(OTf) 3 as a reaction catalyst, and add the NH 2- MXene, after ultrasonic treatment, is placed at room temperature for reaction, washed and then dried to obtain COF@MXene.

[0007] In the above functionalized MXene-based material, in step 1), the preparation method of the MXene includes the following steps: adding Ti 3 AlC 2 powder to the etching reagent KOH, stirring to obtain a uniform MAX-phase dispersion, then transferring it to a reactor and carrying out hydrothermal reaction at 120 °C for 24 h. After the reaction, it is washed until the supernatant is neutral, and then the precipitate is collected and dried to obtain MXene solid.

[0008] In the above functionalized MXene-based material, in step 1), MXene:APTES = 30 mg:200 μL.

[0009] In the above functionalized MXene-based material, in step 2), according to the molar ratio, TAPB:BTCA = 1:1.

[0010] Application of the above functionalized MXene-based material in the separation and enrichment of trace endocrine disruptors BPs.

[0011] Application of the above functionalized MXene-based material in the detection of trace endocrine disruptors BPs.

[0012] For the above application, the method is as follows:

[0013] 1) Add a quantitative amount of COF@MXene to a container containing the water sample to be tested, adjust the pH, and then shake the water sample so that the BPs in the water sample are fully adsorbed on the COF@MXene;

[0014] 2) Transfer the shaken container into a centrifuge tube, centrifuge it. After the COF@MXene is separated from the supernatant, remove the supernatant, and then add an eluent to elute the environmental BPs to be tested on the COF@MXene;

[0015] 3) Collect the eluent and filter it through a microporous membrane to obtain the sample to be tested;

[0016] 4) Analyze the content of environmental endocrine disruptors in the sample to be tested by HPLC.

[0017] In the above application, in step 1), COF@MXene: water sample to be tested = 2 g:50 L, and the pH is adjusted to 6.

[0018] In the above application, in step 4), the chromatographic column used for HPLC analysis is a Zafex C18 column (5 μm, 4.6×150 mm), the column temperature is 35 °C, the injection volume is 20 μL, the mobile phase is 70% (v / v) methanol aqueous solution, and the flow rate is 1 mL / min.

[0019] In the above application, the endocrine disruptors are 2-hydroxy-4-methoxybenzophenone BP-3, 2,4-dihydroxybenzophenone BP-1, 4-hydroxybenzophenone 4-HBP, and 2,2'-dihydroxy-4-methoxybenzophenone BP-8.

[0020] In the detection method of the present invention, low-concentration EDCs in water samples are adsorbed and extracted by using COF@MXene, and then eluted, thereby obtaining an enriched BPs sample. Moreover, the present invention also optimizes the HPLC analysis conditions for such samples, making the detection method have the advantages of low cost and high sensitivity. Description of the Drawings

[0021] Figure 1 Effect of the dosage of adsorbent COF@MXene on the extraction efficiency of different endocrine disruptors:

[0022] Figure 2 Effect of the adsorption time of adsorbent COF@MXene on the extraction efficiency of different endocrine disruptors:

[0023] Figure 3 Effect of solution pH on the extraction efficiency of COF@MXene adsorbent:

[0024] Figure 4 Effect of elution solvent on the extraction efficiency of adsorbent COF@MXene:

[0025] Figure 5 Effect of eluent volume on the extraction efficiency of adsorbent COF@MXene:

[0026] Figure 6 Effect of elution time on the extraction efficiency of adsorbent COF@MXene.

[0027] Figure 7 Effect of the volume of different endocrine disruptors on the extraction efficiency of adsorbent COF@MXene.

[0028] Figure 8 For the unspiked cookie sample (a), the chromatogram of the cookie sample spiked with 10 ng g -1 BPs (b).

[0029] Figure 9 For the cyclic performance diagram of COF@MXene. Detailed implementation mode

[0030] The present invention will be further described and explained below in conjunction with the accompanying drawings and specific implementation modes.

[0031] Example 1 Preparation of COF@MXene

[0032] In this example, the preparation method of the solid-phase extractant COF@MXene includes the following steps:

[0033] (1) Preparation of MXene: Using 5 mol / L KOH as the etching reagent, add 300 mg of Ti 3 AlC 2 powder to 30 mL of the etching reagent, first stir at room temperature for 5 min to obtain a uniform MAX-phase dispersion. Subsequently, transfer it to a 50 mL reactor and carry out a hydrothermal reaction at 120 °C for 24 h. After the reaction, wash the alkaline product with a large amount of deionized water until the pH of the supernatant is about 7. All alkaline-containing supernatants are treated according to laboratory standards. Then collect the precipitate and vacuum dry it at 60 °C for 24 h to obtain the dry MXene solid.

[0034] (2) Preparation of NH 2 -MXene: Use APTES to perform amino-terminal modification on the synthesized MXene. Disperse 30 mg of MXene in 15 mL of ethanol and deionized water with a volume ratio of 1:3, and then slowly drop 200 μL of APTES into the above solution. Stir at 800 rpm at room temperature for 24 h, wash it alternately with deionized water and ethanol 5 times to remove unbound APTES, and vacuum dry the purified product overnight at 50 °C. The dried powder is NH 2 -MXene.

[0035] (3) Preparation of COF@MXene: Dissolve 12.64 mg of TAPB (0.698 mmol) in 3.5 mL of dioxane / mesitylene (1:2, v / v), and then add 42.5 μL of benzaldehyde to obtain solution A. Similarly, dissolve 5.895 mg of BTCA (0.698 mmol) in 3.5 mL of dioxane / mesitylene (1:2, v / v), and then add 38 μL of aniline (0.6 mmol) to obtain solution B. Subsequently, mix solution A and solution B and add 0.5 mg of Sc(OTf) 3 as a reaction catalyst. Immerse the prepared NH2-MXene in the reaction solution, sonicate for 10 min, then place it at room temperature for reaction for 48 h, wash it with dioxane / mesitylene (1:2, v / v) to remove residual monomers, and vacuum dry it at 60 °C for 24 h to obtain COF@MXene.

[0036] Example 2: Influence of Adsorbent Dosage on the Extraction Efficiency of COF@MXene Adsorbent

[0037] 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg of COF@MXene were respectively added to 10 mL of the sample solution, where the concentration of 4HBP was 2 mg / L -1 , the concentration of BP1 was 2 mg / L -1 , the concentration of BP8 was 2 mg / L -1 , and the concentration of BP3 was 2 mg / L -1 . The pH was adjusted to 6.0. Adsorption was carried out with shaking for 20 min. After extraction, centrifugation was performed, and then the supernatant was filtered through a 0.22-μm filter membrane, and finally high-performance liquid chromatography analysis was carried out. The results are as Figure 1 shown. The adsorption efficiency reached the highest when the dosage of COF@MXene was 20 mg.

[0038] Example 3: Influence of Adsorption Time on the Extraction Efficiency of COF@MXene Adsorbent

[0039] 20 mg of COF@MXene was added to 10 mL of the sample solution, where the concentration of 4HBP was 2 mg / L -1 , the concentration of BP1 was 2 mg / L -1 , the concentration of BP8 was 2 mg / L -1 , and the concentration of BP3 was 2 mg / L -1 . The pH was adjusted to 6.0. Shaking was carried out for 1 min, 3 min, 5 min, 8 min, 10 min, 15 min, 20 min, and 25 min respectively. After extraction, centrifugation was performed, and then the supernatant was filtered (through a 0.22-μm filter membrane), and finally high-performance liquid chromatography analysis was carried out. The results are as Figure 2 shown. The adsorption efficiency reached the highest when the adsorption time was 15 min.

[0040] Example 4: Influence of Solution pH on the Extraction Efficiency of COF@MXene Adsorbent

[0041] 20 mg of COF@MXene was added to 10 mL of the sample solution, where the concentration of 4HBP was 2 mg / L -1 , the concentration of BP1 was 2 mg / L -1 , the concentration of BP8 was 2 mg / L -1 , and the concentration of BP3 was 2 mg / L -1 . The pH was adjusted to 1, 3, 5, 7, 9, and 11 respectively, and shaking was carried out for 15 min. After extraction, centrifugation was performed, and then the supernatant was filtered (through a 0.22-μm filter membrane), and finally high-performance liquid chromatography analysis was carried out. The results are as Figure 3As shown, when the solution pH is 5 - 7, the adsorption efficiency is above 90%. Since the initial solution pH is 6, therefore, pH 6 is selected for the following experiments.

[0042] Example 5 Influence of Eluent Type on the Extraction Efficiency of COF@MXene Adsorbent

[0043] Add 20 mg of COF@MXene into 10 mL of the sample solution, where the concentration of 4HBP is 2 mg / L -1 and the concentration of BP1 is 2 mg / L -1 and the concentration of BP8 is 2 mg / L -1 , and the concentration of BP3 is 2 mg / L -1 , adjust the pH to 6.0, and shake for adsorption for 15 min. After extraction, centrifuge and then ultrasonically elute with 15 mL of methanol, 15 mL of ethanol, 15 mL of 0.1 mol / L HCl, and 15 mL of acetonitrile for 10 min respectively. Finally, filter the eluate (0.22 μm filter membrane) and then perform high - performance liquid chromatography analysis. The results are as Figure 4 shown, the response signal is the strongest when the eluent is ethanol.

[0044] Example 6 Influence of Eluent Volume on the Extraction Efficiency of COF@MXene Adsorbent

[0045] Add 20 mg of COF@MXene into 10 mL of the sample solution, where the concentration of 4HBP is 2 mg / L -1 and the concentration of BP1 is 2 mg / L -1 and the concentration of BP8 is 2 mg / L -1 , and the concentration of BP3 is 2 mg / L -1 , adjust the pH to 6.0, and shake for adsorption for 15 min. After extraction, centrifuge and then ultrasonically elute with 0.2 mL, 0.5 mL, 1 mL, 3 mL, 5 mL, 8 mL, 10 mL, 15 mL of ethanol for 10 min. Finally, filter the eluate (0.22 μm filter membrane) and then perform high - performance liquid chromatography analysis. The results are as Figure 5 shown, the response signal is the strongest when the eluent volume is 0.2 mL.

[0046] Example 7 Influence of Elution Time on the Extraction Efficiency of COF@MXene Adsorbent

[0047] Add 20 mg of COF@MXene into 10 mL of the sample solution, where the concentration of 4HBP is 2 mg / L -1 and the concentration of BP1 is 2 mg / L -1 and the concentration of BP8 is 2 mg / L -1 , and the concentration of BP3 is 2 mg / L -1, Adjust the pH to 6.0 and shake for adsorption for 15 min. After extraction, centrifuge and then ultrasonically elute with 0.2 mL of ethanol. The elution times are 1 min, 3 min, 5 min, 8 min, 10 min, and 15 min respectively. Finally, filter the eluate (0.22 μm filter membrane) and then perform high performance liquid chromatography analysis. The results are as Figure 6 shown, and the response signal is the strongest when the elution time is 10 min.

[0048] Effect of solution volume on extraction efficiency of COF@MXene adsorbent in Example 8

[0049] Add 20 mg of COF@MXene to 10 mL of the sample solution, where the concentration of 4HBP is 2 mg L -1 , the concentration of BP1 is 2 mg L -1 , the concentration of BP8 is 2 mg L -1 , and the concentration of BP3 is 2 mg L -1 , dilute to 20 mL, 40 mL, 50 mL, 60 mL, 80 mL, and 100 mL respectively, adjust the pH to 6.0, and shake for adsorption for 15 min. After extraction, centrifuge and then ultrasonically elute with 0.2 mL of ethanol for 10 min. Finally, filter the eluate (0.22 μm filter membrane) and then perform high performance liquid chromatography analysis. The results are as Figure 7 shown, and the response signal is the strongest when the solution is expanded to 50 mL.

[0050] In summary, the finally selected experimental conditions are: adsorbent dosage 20 mg, extraction time 10 min, solution pH 6, volume 50 mL, elution solvent ethanol, elution solvent volume 0.2 mL, and ultrasonic elution time 10 min.

[0051] Detection of BPs in Example 9

[0052] In this example, the solid phase extraction-HPLC-UV detection method for typical environmental endocrine disruptors in water samples and foods is as follows:

[0053] The preparation methods for noodle and biscuit samples are as follows: Noodles and biscuits were obtained from a local supermarket (Shenyang, China) and stored at -6 °C before analysis. Take an appropriate amount of thawed samples, grind and homogenize them. Transfer the homogeneous cereal food sample (0.5 g) into a 12 mL centrifuge tube, and then add ACN (5 mL) (1% acetic acid). Shake for 1 min, let stand for 60 min, vortex at 2000 rpm for 1 min, and dry the supernatant with nitrogen. Finally, dissolve the residue in 200 μL of MeOH and filter with a 0.22 μm polytetrafluoroethylene filter for subsequent dispersive solid phase extraction procedures.

[0054] (1) Solid-phase extraction: Place 20 mg of the extraction material COF@MXene prepared in Example 1 in a reagent bottle, add it to the sample solution (water sample: 50 mL; biscuit and noodle samples: 20 mL), put it in a constant-temperature shaking incubator, mix and shake well at 30 °C at a speed of 200 rpm for 15 min, then take it out, and centrifuge at 8000 rpm for 8 min to separate COF@MXene from the solution. Then take 0.2 mL of 1 mol L -1 ethanol, elute by ultrasound. After 10 min, filter with a 0.22 μm polytetrafluoroethylene filter, and analyze the filtrate by HPLC.

[0055] (2) Analyze the BPS content in the test sample prepared in the previous step by HPLC. The liquid chromatography separation and determination conditions are as follows: The chromatographic column used in HPLC is Zafex-C18 (150 mm × 4.6 mm, 5 μm). The mobile phases A and B are methanol and water (70 / 30, v / v) respectively, and an isocratic elution mode is selected. The flow rate, injection volume, detection wavelength and column temperature are set to 1.0 mL min-1, 20 μL, 290 nm and 30 °C respectively.

[0056] Determination of the linear range and detection limit in Example 10

[0057] Use this method to test the linear range and detection limit of 4 different BPs. The specific detection steps are as in steps (1) and (2) of Example 2. When analyzing by HPLC, the mobile phase is methanol and water (70 / 30, v / v), and the flow rate is 1 mL / min. The linear range and detection limit of 4 different BPs are shown in Table 1. The results show that the method of the present invention has a low detection limit.

[0058] Table 1 Linear range, detection limit, quantification limit and intra-day and inter-day precision of the detection of 4 different BPs in different matrices by this method.

[0059]

[0060] Spiked recovery test in Example 11

[0061] To explore the applicability of this method, we analyzed BPs in river water, biscuit and noodle samples. As shown in the table, the recoveries of BPs in river water, bread and noodle samples are 92.20%-108.67% (RSD = 1.0%-4.8%), 93.00%-102.60% (RSD = 1.4%-5.6%) and 93.8%-106.01% (RSD = 1.3%-4.8%) respectively. The chromatograms of unspiked biscuit samples and biscuit samples spiked with 10 ng g -1 BPs are as Figure 8As shown. The results show that the adsorbent has a high recovery rate and good precision, and can be used for the enrichment and detection of trace BPs in actual environmental and food samples.

[0062] Table 2 Recovery analysis table of COF@MXene for actual samples

[0063]

[0064] Example 12 Reusability

[0065] Reusability is a key parameter for evaluating the stability of the adsorbent and the feasibility of the SPE method. To study the reusability of COF@MXene, the adsorbent was collected after completing the adsorption / desorption cycle. As Figure 9 shown, the recovery rate of COF@MXene remained unchanged within 5 cycles. After 5 cycles, the recovery rate decreased slightly, but the extraction efficiency still remained above 80%. This further proves that COF@MXene has good recyclability.

Claims

1. A functionalized MXene-based material, characterized in that: The preparation method comprises the following steps: 1) Preparation of NH2-MXene: MXene was dispersed in ethanol and deionized water, APTES was slowly added, stirred, washed, and dried to obtain NH2-MXene; 2) Preparation of COF@MXene: TAPB was dissolved in dioxane / mesitylene, benzaldehyde was added to obtain solution A, BTCA was dissolved in dioxane / mesitylene, aniline was added to obtain solution B, solution A and solution B were mixed, 0.5 mg Sc(OTf)3 was added as a reaction catalyst, NH2-MXene obtained in step 1) was added, after ultrasonic treatment, the mixture was allowed to react at room temperature, washed and dried to obtain COF@MXene.

2. A functionalized MXene-based material according to claim 1, characterized in that: In step 1), the preparation method of MXene includes the following steps: adding Ti3AlC2 powder to the etching reagent KOH, stirring to obtain a uniform MAX phase dispersion, then transferring it to a reactor, hydrothermally reacting it at 120°C for 24 hours, washing after the reaction until the supernatant is neutral, and then collecting the precipitate and drying it to obtain a MXene solid.

3. A functionalized MXene-based material according to claim 1, characterized in that: In step 1), MXene: APTES = 30 mg: 200 μL.

4. A functionalized MXene-based material according to claim 1, characterized in that: In step 2), in molar ratio, TAPB:BTCA=1:

1.

5. Use of the functionalized MXene-based material according to any one of claims 1 to 4 in the separation and enrichment of trace endocrine disruptors BPs.

6. Use of the functionalized MXene-based material according to any one of claims 1 to 4 in the detection of trace endocrine disruptors BPs.

7. Use according to claim 5 or 6, characterized in that Here’s how: 1) Add a certain amount of COF@MXene to a container containing a water sample to be tested, adjust the pH, and then oscillate the water sample to allow the BPs in the water sample to be fully adsorbed on the COF@MXene; 2) The shaken container is transferred into a centrifuge tube and centrifuged. After COF@MXene is separated from the supernatant, the supernatant is removed, and then an eluent is added to elute the environmental BPs to be tested on the COF@MXene; 3) Collect the eluate and filter it through a microporous membrane to obtain the sample to be tested; 4) Performing HPLC analysis on the content of environmental endocrine disruptors in the sample to be tested.

8. The use according to claim 7, characterized in that: In step 1), COF@MXene: water sample to be tested = 2 g: 50 L, and the pH is adjusted to 6.

9. The use according to claim 7, characterized in that: In step 4), the chromatographic column used in the HPLC analysis is a Zafex C18 column (5 μm, 4.6×150 mm), the column temperature is 35° C., the injection volume is 20 μL, the mobile phase is 70% (v / v) methanol aqueous solution, and the flow rate is 1 mL / min.

10. The use according to claim 5 or 6, characterized in that The endocrine disruptors are 2-hydroxy-4-methoxybenzophenone BP-3, 2,4-dihydroxybenzophenone BP-1, 4-hydroxybenzophenone 4-HBP, and 2,2'-dihydroxy-4-methoxybenzophenone BP-8.

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