A synthesis method of MOFs composite materials and its application in glyphosate detection

Abstract

The present invention provides a method for synthesizing a MOFs composite material and its application in glyphosate detection, belonging to the technical field of chemical analysis and detection. The method for synthesizing the MOFs composite material comprises: S1, using imidazole-2-carboxaldehyde, zinc acetate dihydrate, and zinc porphyrin, stirring and synthesizing at room temperature to prepare a MOFs composite material, represented as ZnTCPP@ZIF-90. The method for detecting the glyphosate concentration by colorimetry using ZnTCPP@ZIF-90 comprises: S2, preparing glyphosate of different concentrations as a standard solution, adding the solution to the MOFs composite material solution, adding an OPD solution to the system, incubating under light, and establishing a linear relationship between the glyphosate concentration and the ultraviolet absorption intensity / fluorescence intensity; S3, detecting the solution to be tested, and comparing the test result with the result of the standard solution to obtain the concentration of the solution to be tested. This method can achieve efficient detection of glyphosate.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical analysis and detection, and particularly relates to a synthesis method of a MOFs composite material and its application in glyphosate detection. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Metal-organic frameworks (MOFs) are a class of porous coordination polymers composed of metal nodes or clusters connected by organic ligands. They possess characteristics such as large surface area, ease of synthesis, and structural tunability, and are widely used in catalysis, energy storage, and sensing. Among them, ZIF-90, a zeolitic imidazolate framework material, has advantages such as large surface area, uniform pore structure, high hydrothermal and chemical stability, easy modification, and simple synthesis. It can be widely used in separation, adsorption, catalysis, and drug delivery. ZnTCPP, a derivative of TCPP, exhibits excellent photoresponsive oxidase activity and fluorescence properties.

[0004] Glyphosate is one of the most commonly used herbicides worldwide. Due to its overuse, it has seeped into groundwater and soil systems, posing a serious threat to aquatic and terrestrial organisms. As a potent endocrine disruptor, glyphosate not only causes severe damage to placental cells but also causes damage to human DNA, plasma, and epithelial cells. Therefore, glyphosate detection is a crucial measure to ensure human health and safety.

[0005] Currently, the main methods for glyphosate detection include gas chromatography (GC), liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), and enzyme-linked immunosorbent assay (ELISA). However, high costs and cumbersome sample pretreatment limit their application in rapid detection. Therefore, there is an urgent need to develop sensors based on MOF composites for highly sensitive and specific dual-modal detection of glyphosate. Summary of the Invention

[0006] In response to the current status of glyphosate detection, the purpose of the present invention is to provide a synthesis of a MOFs composite material and its application in glyphosate detection. The prepared MOFs composite material is incubated with glyphosate. Glyphosate will specifically recognize the Zn nodes of the MOFs composite material, destroying the material and releasing ZnTCPP molecules, which can be used to detect glyphosate content in water.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a method for synthesizing a MOFs composite material, comprising:

[0009] Dissolve zinc porphyrin, zinc acetate dihydrate, and imidazole-2-carboxaldehyde in an organic solvent, stir at room temperature for 2 to 3 hours, and centrifuge to obtain a solution containing ZnTCPP@ZIF-90. Wash with ethanol several times and dry to obtain ZnTCPP@ZIF-90.

[0010] The mass ratio of the zinc porphyrin, zinc acetate dihydrate and imidazole-2-carboxaldehyde is 2.2-2.5:22-25:19-24.

[0011] The MOFs composite material prepared by the above preparation method is synthesized from ZnTCPP and ZIF-90. Among them, ZIF-90 is a zeolite imidazole ester framework material with the advantages of large specific surface area, uniform pore structure, high hydrothermal stability and chemical stability, easy modification and simple synthesis. It can be widely used in separation, adsorption, catalysis, drug delivery and other fields. ZnTCPP, as a derivative of TCPP, has good photoresponsive oxidase activity and fluorescence properties. ZnTCPP is encapsulated by ZIF-90, which can make the MOFs composite material have both photoresponsive oxidase activity and fluorescence properties. By utilizing the specific recognition of glyphosate, the outer ZIF-90 shell is destroyed, and the ZnTCPP molecules are released, which can achieve effective detection of glyphosate.

[0012] Among them, ZnTCPP@ZIF-90 has weak light-responsive oxidase activity and fluorescence properties in the buffer solution due to the encapsulation effect of ZIF-90; when glyphosate solution is added, glyphosate and imidazole-2-carboxaldehyde react with Zn 2+ Competitive coordination on the ZIF-90 material causes it to disintegrate, releasing ZnTCPP molecules. Due to ZIF-90's unique recognition of glyphosate and the excellent photoresponsive oxidase activity and fluorescence properties of ZnTCPP molecules, ZnTCPP@ZIF-90 exhibits unique dual-modal detection of glyphosate, enabling rapid and highly selective detection of glyphosate in aqueous solution. The enhanced photoresponsive oxidase activity and fluorescence intensity of the MOF composite material can be used to quantitatively determine glyphosate concentration.

[0013] The second aspect of the present invention provides a MOFs composite material prepared by the above method.

[0014] The present invention encapsulates ZnTCPP molecules in ZIF-90 to synthesize ZnTCPP@ZIF-90 for detecting glyphosate.

[0015] The third aspect of the present invention provides the use of the above-mentioned MOFs composite material in the detection of glyphosate.

[0016] A fourth aspect of the present invention provides a method for colorimetrically detecting glyphosate concentration using the ZnTCPP@ZIF-90, comprising:

[0017] Glyphosate of different concentrations was prepared as a standard solution; the MOFs composite material was added to the glyphosate solution of different concentrations and mixed evenly, and then an o-phenylenediamine (OPD) solution was added to the reaction system. After irradiation for 20 to 25 minutes, the ultraviolet absorption intensity at 425 nm was measured. Based on the measured ultraviolet absorption intensity, a linear relationship between glyphosate concentration and ultraviolet absorption intensity was established;

[0018] Repeat the above steps to detect a glyphosate test solution of unknown concentration, and compare the test result with the test result of the standard solution to obtain the concentration value of the glyphosate test solution.

[0019] A fifth aspect of the present invention provides a method for detecting glyphosate concentration using the ZnTCPP@ZIF-90 fluorescence method, comprising:

[0020] Glyphosate at different concentrations was prepared as a standard solution. The MOFs composite material was added to the glyphosate solution at different concentrations and mixed evenly. Then, an o-phenylenediamine (OPD) solution was added to the reaction system. After irradiation for 20 to 25 minutes, the fluorescence emission peak intensities of the OPDox and ZnTCPP molecules were detected. Based on the measured fluorescence emission intensities, a linear relationship between glyphosate concentration and fluorescence intensity was established.

[0021] Repeat the above steps to detect the glyphosate test solution, and compare the test result with the test result of the standard solution to obtain the concentration value of the glyphosate test solution.

[0022] Since the synthesized ZnTCPP@ZIF-90 has a large number of zinc metal nodes, the phosphate groups of glyphosate are used to compete with the zinc metal nodes for coordination, causing the ZIF-90 material to disintegrate and release ZnTCPP molecules.

[0023] Among them, OPD serves as the signal indicator of the reaction, which can be catalyzed by ZnTCPP molecules to OPDox, converting the glyphosate concentration signal into a light / electrical signal that is easy to observe.

[0024] The beneficial effects of the present invention are:

[0025] (1) The synthesis process of ZnTCPP@ZIF-90 is simple, time-saving, and the raw materials are inexpensive and readily available. In the field of colorimetric and fluorescence sensing, the specific recognition of glyphosate by ZIF-90 can achieve efficient glyphosate detection. In summary, the ZnTCPP@ZIF-90 of the present invention is a low-cost, convenient, and sensitive probe for glyphosate detection, and has broad application prospects in the fields of colorimetric and fluorescence sensing.

[0026] (2) The method of the present invention is simple, low-cost, universal, and easy to scale up. The cascade system of ZnTCPP@ZIF-90 is the novelty and uniqueness of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0028] Figure 1 Scanning electron microscopy images of ZIF-90 (a) and ZnTCPP@ZIF-90 (b) in Example 1;

[0029] Figure 2 In Example 1, in a HEPES buffer solution at pH = 7.5, (1) is the ultraviolet absorption spectra of ZnTCPP@ZIF-90; ZIF-90+OPD; ZnTCPP@ZIF-90+OPD; ZIF-90 and glyphosate+OPD; ZnTCPP@ZIF-90 and glyphosate; ZnTCPP@ZIF-90 and glyphosate+OPD; (2) is the fluorescence spectra of ZnTCPP@ZIF-90; ZIF-90+OPD; ZnTCPP@ZIF-90+OPD; ZIF-90 and glyphosate+OPD; ZnTCPP@ZIF-90 and glyphosate; ZnTCPP@ZIF-90 and glyphosate+OPD;

[0030] Figure 3 The ZnTCPP@ZIF-90 colorimetric method for glyphosate detection in Example 2, where a is the UV absorption intensity spectrum at different glyphosate concentrations (ah: 0.1-3.5 μg / mL), and b is the linear relationship between glyphosate concentration and UV absorption intensity; the ZnTCPP@ZIF-90 fluorescence method for glyphosate detection, where c is the fluorescence intensity spectrum at different glyphosate concentrations (ig: 0.2-3 μg / mL), and d is the linear relationship between glyphosate concentration and fluorescence intensity. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] A method for synthesizing a MOFs composite material, comprising:

[0033] Dissolve zinc porphyrin, zinc acetate dihydrate, and imidazole-2-carboxaldehyde in an organic solvent, stir at room temperature for 2 to 3 hours, and centrifuge to obtain a solution containing ZnTCPP@ZIF-90. Wash with ethanol several times and dry to obtain ZnTCPP@ZIF-90.

[0034] The mass ratio of zinc porphyrin, zinc acetate dihydrate, and imidazole-2-carboxaldehyde is 2.2-2.5:22-25:19-24. Specifically, ZnTCPP@ZIF-90 is synthesized by dissolving 22 mg of zinc acetate dihydrate, 19 mg of imidazole-2-carboxaldehyde, and 2.2 mg of zinc porphyrin in 3 mL of DMF, stirring at room temperature for 2 hours, and centrifuging to obtain a solution containing ZnTCPP@ZIF-90. The solution is washed three times with ethanol and dried for later use.

[0035] In some embodiments, the mass ratio of zinc porphyrin, zinc acetate dihydrate, and imidazole-2-carboxaldehyde is 2.2:22:19.

[0036] In some embodiments, the mass volume ratio of the zinc porphyrin to the organic solvent is 2.2-2.5 mg: 3-4 mL.

[0037] In some embodiments, the organic solvent is N,N-dimethylformamide.

[0038] In some embodiments, the normal temperature is 20-25°C.

[0039] In some embodiments, during the colorimetric detection of glyphosate concentration, the concentration of ZnTCPP@ZIF-90 is 1-1.5 mg / mL; the concentration of OPD is 1-1.2 mM; and the concentration of glyphosate is 0-3.0 μg / mL.

[0040] Preferably, the concentration of ZnTCPP@ZIF-90 is 1 mg / mL, the OPD is 1 mM, and the glyphosate concentration is 0 to 3.0 μg / mL.

[0041] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0042] Example 1

[0043] The preparation process of ZnTCPP@ZIF-90 is as follows:

[0044] S1, synthesis of ZnTCPP@ZIF-90: 22 mg of zinc acetate dihydrate, 19 mg of imidazole-2-carboxaldehyde, and 2.2 mg of zinc porphyrin were dissolved in 3 mL of DMF and stirred at room temperature for 2 h. The resulting solution containing ZnTCPP@ZIF-90 was centrifuged, washed three times with ethanol, and dried for later use, which is the MOFs composite material referred to in the present invention.

[0045] Scanning electron microscopy observation of ZIF-90 and ZnTCPP@ZIF-90, the results obtained are as follows Figure 1 shown. Figure 1 Figure a is a scanning electron microscope image of ZIF-90, showing a cubic structure crystal. Figure 1 (b) is the scanning electron microscopy observation result of ZnTCPP@ZIF-90, showing a cubic structure crystal.

[0046] The UV-visible absorption spectrometer was used to detect and analyze the Figure 2 As shown in the colorimetric system, ZnTCPP@ZIF-90 has weak light-responsive oxidase activity and fluorescence properties; after the addition of glyphosate, ZIF-90 disintegrates and destroys, releasing ZnTCPP molecules and enhancing the light-responsive oxidase activity.

[0047] Example 2

[0048] A method for colorimetrically detecting glyphosate concentration using ZnTCPP@ZIF-90 includes:

[0049] S1, 60μL ZnTCPP@ZIF-90 (1mg mL -1 ) were added with different concentrations of glyphosate solution, and then OPD (1 mM) was added to the reaction system, incubated under light for 20 min, and the ultraviolet absorption signal of the reaction system at 425 nm was measured; the test results were as follows Figure 3 As shown in Figure a, as the amount of glyphosate in the solution increases, the UV absorption intensity also increases. It can be seen that the glyphosate concentration and the UV absorption intensity have a good linear relationship ( Figure 3 In (b), the linear equation is y = 0.1671x - 0.002, where x is glyphosate concentration. The linear range is 0.1 to 3.0 μg / mL, and the detection limit is 0.083 μg / mL. This indicates that ZnTCPP@ZIF-90 has a low UV absorption detection limit for glyphosate and a wide detection range, suggesting promising application.

[0050] S2. Detect the test solution, compare the test result with the test result of the standard solution, and obtain the concentration value of the test solution.

[0051] A method for detecting glyphosate concentration by fluorescence using ZnTCPP@ZIF-90 includes:

[0052] S1, 60μL ZnTCPP@ZIF-90 (1mg mL -1 ) were added with different concentrations of glyphosate solution, and then OPD (1 mM) was added to the reaction system. The reaction was incubated under light for 20 min, and the fluorescence signals at 556 nm, 601 nm, and 652 nm of the reaction system were measured. The detection results were as follows: Figure 3 As shown in Figure c, as the amount of glyphosate in the solution increases, the fluorescence intensity also increases. It can be seen that there is a good linear relationship between glyphosate concentration and fluorescence intensity ( Figure 3 In (d), the linear equation is y = 222.59x - 144.08, where x is the glyphosate concentration. The linear range is 0.2 to 2.5 μg / mL, and the detection limit is 0.042 μg / mL. This indicates that ZnTCPP@ZIF-90 has a low fluorescence intensity detection limit for glyphosate and a wide detection range, suggesting its promising application.

[0053] S3. Detect the test solution, compare the test result with the test result of the standard solution, and obtain the concentration value of the test solution.

[0054] Example 3

[0055] The preparation process of ZnTCPP@ZIF-90 is as follows:

[0056] S1, synthesis of ZnTCPP@ZIF-90: 23.5 mg of zinc acetate dihydrate, 22 mg of imidazole-2-carboxaldehyde, and 2.35 mg of zinc porphyrin were dissolved in 3.5 mL of DMF, stirred at room temperature for 2.5 h, and centrifuged to obtain a solution containing ZnTCPP@ZIF-90. The solution was washed three times with ethanol and dried for later use, which is the MOFs composite material referred to in the present invention.

[0057] The test results show that the MOFs composite material prepared in this example can be applied to colorimetric and fluorescence sensing to achieve efficient detection of glyphosate.

[0058] Example 4

[0059] The preparation process of ZnTCPP@ZIF-90 is as follows:

[0060] S1, synthesis of ZnTCPP@ZIF-90: 25 mg of zinc acetate dihydrate, 24 mg of imidazole-2-carboxaldehyde, and 2.5 mg of zinc porphyrin were dissolved in 4 mL of DMF and stirred at room temperature for 3 h. The resulting solution containing ZnTCPP@ZIF-90 was centrifuged, washed three times with ethanol, and dried for later use, which is the MOFs composite material referred to in the present invention.

[0061] The test results show that the MOFs composite material prepared in this example can be applied to colorimetric and fluorescence sensing to achieve efficient detection of glyphosate.

[0062] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for synthesizing a MOFs composite material, characterized in that: include: Dissolve zinc porphyrin, zinc acetate dihydrate, and imidazole-2-carboxaldehyde in an organic solvent, stir at room temperature for 2-3 hours, and centrifuge to obtain a solution containing ZnTCPP@ZIF-90. Wash the solution with ethanol several times and dry it to obtain ZnTCPP@ZIF-90. The mass ratio of the zinc porphyrin, zinc acetate dihydrate, and imidazole-2-carboxaldehyde is 2.2-2.5:22-25:19-24; The mass volume ratio of the zinc porphyrin to the organic solvent is 2.2-2.5 mg: 3-4 mL; The organic solvent is N,N-dimethylformamide.

2. The method for synthesizing the MOFs composite material according to claim 1, wherein: The mass ratio of the zinc porphyrin, zinc acetate dihydrate, and imidazole-2-carboxaldehyde is 2.2:22:

19.

3. The method for synthesizing the MOFs composite material according to claim 1, wherein: The normal temperature is 20-25°C.

4. The MOFs composite material prepared by the method according to any one of claims 1 to 3.

5. Use of the MOFs composite material according to claim 4 in detecting glyphosate.

6. A method for colorimetrically detecting glyphosate concentration using the ZnTCPP@ZIF-90 according to claim 4, characterized in that: include: Glyphosate of different concentrations is prepared as a standard solution; the MOFs composite material of claim 4 is added to the glyphosate solution of different concentrations and mixed evenly, and then an o-phenylenediamine (OPD) solution is added to the reaction system. After irradiation for 20 to 25 minutes, the ultraviolet absorption intensity at 425 nm is detected, and a linear relationship between the glyphosate concentration and the ultraviolet absorption intensity is established based on the measured ultraviolet absorption intensity; Repeat the above steps to detect a glyphosate test solution of unknown concentration, and compare the test result with the test result of the standard solution to obtain the concentration value of the glyphosate test solution.

7. The method for colorimetric detection of glyphosate concentration using ZnTCPP@ZIF-90 as claimed in claim 6, wherein: The concentration of the ZnTCPP@ZIF-90 is 1-1.5 mg / mL; Alternatively, the concentration of OPD is 1-1.2 mM; Alternatively, the glyphosate concentration is 0-3.0 μg / mL.

8. A method for detecting glyphosate concentration using the ZnTCPP@ZIF-90 fluorescence method according to claim 4, characterized in that: include: Glyphosate of different concentrations is prepared as a standard solution; the MOFs composite material of claim 4 is added to the glyphosate solution of different concentrations and mixed evenly, and then an o-phenylenediamine (OPD) solution is added to the reaction system. After irradiation for 20 to 25 minutes, the fluorescence emission peak intensity of the OPDox and ZnTCPP molecules is detected, and a linear relationship between the glyphosate concentration and the fluorescence intensity is established based on the measured fluorescence emission intensity; Repeat the above steps to detect the glyphosate test solution, and compare the test result with the test result of the standard solution to obtain the concentration value of the glyphosate test solution.

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