Amino-functionalized mil-100(fe) and methods of making and using the same

Abstract

The application belongs to the field of metal organic framework materials, and particularly relates to an amino-functionalized MIL-100(Fe) and a preparation method and application thereof. The amino-functionalized MIL-100(Fe) is a composite of 3-amino-4,5-dihydroxybenzoic acid and MIL-100(Fe), and the mass ratio of the 3-amino-4,5-dihydroxybenzoic acid and the MIL-100(Fe) is 3:8. The composite constructed by the 3-amino-4,5-dihydroxybenzoic acid and the MIL-100(Fe) has the characteristics of high specific surface area and high porosity of the MIL-100(Fe) material, and further introduces functional groups such as phenyl, amino and carboxyl, thereby enhancing the interaction force between the matrix and the analyte, improving the ultraviolet absorption and energy transfer capacity, and thus improving the desorption / ionization efficiency in MALDI-TOF-MS detection.

Description

Technical Field

[0001] This invention belongs to the field of metal-organic framework materials, specifically relating to an amino-functionalized MIL-100(Fe), its preparation method, and its application. Background Technology

[0002] Pesticides play a crucial role in agricultural production by controlling pests and weeds and regulating plant growth. However, due to their toxicity and non-degradability, widespread use and improper disposal lead to pesticide residues in agricultural products, soil, and environmental water. Through the food chain, pesticides accumulate in plants and animals and eventually enter the human body, threatening human safety. Therefore, monitoring pesticide residues in food and the environment is extremely important. Currently, the most widely used pesticide analysis methods include gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), immunoassay, and biosensor methods. However, all of these methods suffer from insufficient stability and accuracy, and cannot achieve high-throughput detection.

[0003] Matrix-assisted laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF-MS) offers advantages such as speed, high throughput, high sensitivity, good salt tolerance, and small sample volume requirements, making it widely used for the analysis and detection of biomacromolecules such as proteins, peptides, nucleic acids, and polymers. In MALDI-TOF-MS detection, the matrix plays a crucial role in efficiently transferring laser energy, accelerating sample ionization, improving sample crystallization, and facilitating internal standard quality calibration.

[0004] Organic matrices, such as α-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB), exhibit poor desorption / ionization efficiency in MALDI-TOF-MS detection due to their weak interaction with small molecule detectable substances. This results in numerous matrix interference peaks, poor reproducibility, and low sensitivity in MALDI-TOF-MS detection of organic matrices, making it impossible to accurately quantify such substances. Summary of the Invention

[0005] The purpose of this invention is to provide an amino-functionalized MIL-100(Fe) to solve the problems of multiple matrix interference peaks, poor reproducibility and low sensitivity in MALDI-TOF-MS detection of organic matrices.

[0006] A second objective of this invention is to provide a method for preparing the above-mentioned amino-functionalized MIL-100(Fe).

[0007] A third objective of this invention is to provide the application of the above-mentioned amino-functionalized MIL-100(Fe) as a matrix in matrix-assisted laser desorption / ionization time-of-flight mass spectrometry.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] An amino-functionalized MIL-100(Fe) is a complex of 3-amino-4,5-dihydroxybenzoic acid and MIL-100(Fe), wherein the mass ratio of 3-amino-4,5-dihydroxybenzoic acid to MIL-100(Fe) is 3:8.

[0010] This invention is pioneering. The composite material constructed from 3-amino-4,5-dihydroxybenzoic acid and MIL-100(Fe) not only possesses the high specific surface area and high porosity of MIL-100(Fe) material, but also introduces functional groups such as phenyl, amino, and carboxyl groups, which enhances the interaction between the matrix and the analyte, improves its ultraviolet absorption and energy transfer capabilities, and thus improves the desorption / ionization efficiency in MALDI-TOF-MS detection.

[0011] Based on the above characteristics, using this amino-functionalized MIL-100(Fe) as a matrix in MALDI-TOF-MS detection exhibits lower background noise and higher signal intensity, which is beneficial to improving the detection accuracy and reliability of small molecules.

[0012] To achieve the second objective mentioned above, the technical solution adopted by the present invention is as follows:

[0013] A method for preparing amino-functionalized MIL-100(Fe) includes the following steps: mixing MIL-100(Fe) and 3-amino-4,5-dihydroxybenzoic acid in water under stirring, followed by solid-liquid separation to obtain amino-functionalized MIL-100(Fe); wherein the mass ratio of 3-amino-4,5-dihydroxybenzoic acid to MIL-100(Fe) is 3:8.

[0014] The preparation method of amino-functionalized MIL-100(Fe) of the present invention promotes the uniform compounding of MIL-100(Fe) and 3-amino-4,5-dihydroxybenzoic acid through an aqueous phase compounding method. The resulting material has uniform particle size, good process controllability, and is suitable for industrial production.

[0015] Preferably, the reaction is carried out at room temperature for more than 1 hour.

[0016] Preferably, the amount of water used is 20-30 mL for every 80 mg MIL-100 (Fe).

[0017] To achieve the third objective mentioned above, the technical solution adopted by this invention is as follows:

[0018] The above-mentioned amino-functionalized MIL-100(Fe) is used as a matrix in matrix-assisted laser desorption / ionization time-of-flight mass spectrometry.

[0019] Using the above-mentioned amino-functionalized MIL-100(Fe) as a matrix for MALDI-TOF-MS testing of small molecules, the results showed low background noise and detection limit, as well as high signal intensity, thus improving the reliability of small molecule detection.

[0020] Preferably, the analyte is a pesticide or a sugar.

[0021] More preferably, the pesticide includes one or more of the following: azoxystrobin, chlorantraniliprole, indoxacarb, triazophos, benzyl sulfoxide, benzalkonium chloride, chlorpyrifos sulfone, piperonyl butyl ether, phosmet, dimethoate, phorate, 3-hydroxycarbofuran, sulfoxide, oxadixyl, ethionyl sulfoxide, and benzyl sulfoxide.

[0022] More preferably, the sugar substance includes mannose and / or arabinose. Attached Figure Description

[0023] Figure 1 The FTIR spectra of MIL-100(Fe) and MIL-100(Fe)-NH2 in Example 1 of this invention;

[0024] Figure 2 XPS and high-resolution XPS spectra of MIL-100(Fe) and MIL-100(Fe)-NH2 in Example 1 of this invention;

[0025] Figure 3 MIL-100(Fe) in Example 1 of this invention Figure 3 a) and MIL-100(Fe)-NH2( Figure 3 b) SEM image;

[0026] Figure 4 The XRD patterns of MIL-100(Fe) and MIL-100(Fe)-NH2 in Example 1 of this invention are shown below.

[0027] Figure 5 The TAG diagrams of MIL-100(Fe) and MIL-100(Fe)-NH2 in Example 1 of this invention are shown below.

[0028] Figure 6 The nitrogen adsorption-desorption curves and pore size distribution diagrams of MIL-100(Fe) and MIL-100(Fe)-NH2 in Example 1 of this invention are shown.

[0029] Figure 7 The UV bandgap spectra of MIL-100(Fe) and MIL-100(Fe)-NH2 in Example 1 of this invention;

[0030] Figure 8 The images shown are SALDI-TOF-MS images of pesticides detected by CHCA, DHB, and MIL-100(Fe)-NH2 as matrices in Experimental Example 4 of this invention.

[0031] Figure 9 This is a comparison of mass spectrum peak intensities for MIL-100(Fe) and MIL-100(Fe)-NH2 as matrices in Experimental Example 4 of this invention;

[0032] Figure 10 The image shows the SALDI-TOF-MS chromatograms of six pesticides at a concentration of 1 mg / mL detected by MIL-100(Fe)-NH2 in Experiment Example 4 of this invention.

[0033] Figure 11 This is the SALDI-TOF-MS image of mannose detected using MIL-100(Fe)-NH2 as a matrix in Experimental Example 6 of this invention;

[0034] Figure 12 This is a SALDI-TOF-MS image of arabinitol detected using MIL-100(Fe)-NH2 as a matrix in Experimental Example 6 of this invention. Detailed Implementation

[0035] MIL-100(Fe) is a MOF material with Fe as the coordinating metal and pyromellitic acid as the ligand. It can be used for the adsorption of gases and pollutants and can also be used as a Lewis acid catalyst. In this invention, 3-amino-4,5-dihydroxybenzoic acid is used to modify it with amino groups. The amino functional groups enhance the interaction between the matrix and the analyte. The lone electrons of the nitrogen atom in the aromatic amine form conjugated π molecular orbitals with the benzene ring, resulting in electronic transitions. This allows it to absorb most wavelengths related to ultraviolet light, improving the material's ultraviolet absorption and energy transfer capabilities. This improves the desorption / ionization efficiency of the MALDI-TOF-MS matrix, thus making it a novel matrix that enhances the detection performance of MALDI-TOF-MS for small molecules such as pesticides and sugars.

[0036] The implementation process of the present invention will be described in detail below with reference to specific embodiments. In the following embodiments, MIL-100(Fe) was purchased from Beijing Bailingwei Technology Co., Ltd.

[0037] I. Specific Examples of the Amino-functionalized MIL-100(Fe) and its Preparation Method of the Present Invention

[0038] Example 1

[0039] The amino-functionalized MIL-100(Fe) of this embodiment is a complex of 3-amino-4,5-dihydroxybenzoic acid and MIL-100(Fe), with a mass ratio of 3-amino-4,5-dihydroxybenzoic acid to MIL-100(Fe) of 3:8.

[0040] The preparation method of amino-functionalized MIL-100(Fe) in this embodiment adopts the following steps: 80 mg of MIL-100(Fe) is added to 20 mL of deionized water and stirred for 10 min to form a uniform suspension. 30 mg of 3-amino-4,5-dihydroxybenzoic acid is added as a ligand to the above suspension and stirred at room temperature for 1 h. Solid-liquid separation is performed to obtain a precipitate. The precipitate is washed three times with deionized water and methanol respectively. The washed precipitate is placed in a vacuum oven at 60 °C and dried overnight to obtain a light brown powder, namely MIL-100(Fe)-NH2.

[0041] II. Specific Examples of the Application of the Amino-functionalized MIL-100(Fe) of the Present Invention

[0042] Example 2

[0043] In this embodiment, MIL-100(Fe)-NH2 powder was dissolved at a ratio of 1 mg / mL in a mixed solvent of ethanol and water at a volume ratio of 4:1, and sonicated for 15 min to ensure complete dissolution, thus completing the preparation of the matrix solution. 1 μL of the matrix solution was spotted onto the matching target plate, dried at room temperature, and then 1 μL of the test solution was added. After the solvent evaporated and crystallized, SALDI-TOF-MS analysis was performed directly. The test used positive ion scanning mode; the scanning range was 100-600 DA; a high peak power, high pulse energy ND:YAG laser was used to provide a 1000 Hz high-frequency laser, and the MS spectrum was obtained by averaging 400 shots per position.

[0044] When testing environmental water samples, 15 mL of the environmental water sample is concentrated to complete dryness using a vacuum concentrator. Then, 200 μL of 70% (v / v) acetone-water solution is added, followed by 2 μL of 1 μg / mL TPP (triphenyl phosphate) internal standard solution (solvent: 70% (v / v) acetone-water solution) to obtain a test solution with an internal standard concentration of 10 ng / mL. The solution is then centrifuged at 14000 rpm for 10 min, and the supernatant (i.e., the test solution) is retained for SALDI-TOF-MS testing.

[0045] III. Experimental Examples

[0046] Experimental Example 1: Infrared and X-ray photoelectron spectroscopy analysis of MIL-100(Fe) and MIL-100(Fe)-NH2

[0047] Infrared spectroscopy and X-ray photoelectron spectroscopy were performed on MIL-100(Fe) in Example 1 and the prepared MIL-100(Fe)-NH2. The results are as follows: Figure 1 and Figure 2 As shown.

[0048] Figure 1 The FT-IR spectra of MIL-100(Fe) and MIL-100(Fe)-NH2 are shown below. Figure 1 As shown, 1622cm -1 The peaks at 1446 and 1382 cm⁻¹ are characteristic vibrations of the C=O bond. -1 The peaks at 1712 cm⁻¹ represent the symmetric and asymmetric vibrations of the -OCO- group, respectively. -1 A C=O vibration peak can be observed at 713 cm⁻¹. -1 The CH vibration is present. In addition to the characteristic peaks shared by these two MOFs, an additional peak at 1246 cm⁻¹ is observed in amino-modified MIL-100(Fe)-NH₂. -1 2590cm -1 and 3210cm -1 The peaks are due to the stretching vibrations of the CN, CH, and NH bonds in the aromatic amine. This demonstrates that the ligands have been successfully loaded into the structure of MIL-100(Fe).

[0049] Figure 2 The XPS spectra of MIL-100(Fe) and MIL-100(Fe)-NH2 are shown. Compared with MIL-100(Fe), the amino-functionalized MOF material shows an N1s peak at 398 eV. In the high-resolution N1s spectrum, 396.8 eV and 398.9 eV correspond to NH2 and NC, respectively, indicating the presence of amino groups in the ligand-modified MIL-100(Fe)-NH2. The high-resolution C1s peak at 282 eV is divided into three parts: 271.4 eV, 272.8 eV, and 275.1 eV, corresponding to CC / CN, C=C, and OC=O in MIL-100(Fe)-NH2. The XPS experimental results confirm the successful modification of MIL-100(Fe).

[0050] Experimental Example 2: SEM and XRD Analysis of MIL-100(Fe) and MIL-100(Fe)-NH2

[0051] SEM and XRD analyses were performed on MIL-100(Fe) and MIL-100(Fe)-NH2 in Example 1, and the results were... Figure 3 and Figure 4 As shown.

[0052] Figure 3 MIL-100(Fe)( Figure 3 a) and MIL-100(Fe)-NH2( Figure 3 b) SEM image, by Figure 3 It can be seen that both MOFs exhibit irregular shapes and obvious aggregation, with particles interconnected to form a porous structure. Compared with MIL-100(Fe), the amino-modified MIL-100(Fe)-NH2 shows more adhesion between the layered structures.

[0053] The crystal structures of MIL-100(Fe) and MIL-100(Fe)-NH2 were verified by XRD analysis. Figure 4 The figures show the XRD patterns of two MOFs. As can be seen from the figures, the intensity of these characteristic peaks decreases after amino ligand modification.

[0054] Experimental Example 3: Thermal stability, specific surface area, pore size distribution, and UV-VIS analysis of MIL-100(Fe) and MIL-100(Fe)-NH2

[0055] Thermogravimetric analysis was performed on MIL-100(Fe) and MIL-100(Fe)-NH2 from Example 1 to test the thermodynamic stability of the materials. Figure 5 As shown, due to the release of water and solvent vapor from the MOF structure and the dehydration of bound water at 100℃, MIL-100(Fe) exhibits its first significant mass loss at 100℃. At 400℃, the MOF decomposes, leading to a sharp decrease in mass. Between 100 and 450℃, the weight loss of MIL-100(Fe)-NH2 occurs earlier than that of MIL-100(Fe), indicating that amino functionalization has a slight effect on the thermal stability of MIL-100(Fe).

[0056] The specific surface area and pore size distribution of the two MOF materials were determined using a 77K N2 adsorption-desorption isotherm, and the results are as follows: Figure 6 As shown, both MIL-100(Fe) and MIL-100(Fe)-NH2 exhibit typical type I adsorption isotherms. The specific surface area of ​​MIL-100(Fe)-NH2 decreases after ligand modification, indicating that the introduction of amino groups leads to the aggregation of MIL-100(Fe) and pore blockage.

[0057] MIL-100(Fe) and MIL-100(Fe)-NH2 were characterized by UV-Vis, and their UV absorption spectra (TAUC diagrams) are shown below. Figure 7 As shown, after ligand modification, the band gap of MIL-100(Fe) decreased from 2.06 eV to 1.51 eV. The lower band gap allows the MOF to absorb light over a wider wavelength range, indicating that the introduction of amino groups lowers the laser absorption threshold and improves the laser desorption / ionization (LDI) efficiency of the analyte.

[0058] Experiment Example 4: Comparison of SALDI-TOF-MS Analysis of Different Matrix

[0059] CHCA was dissolved in a 70% (v / v) acetonitrile-water solution at a concentration of 10 mg / mL to obtain the CHCA matrix. DHB was dissolved in a 50% (v / v) acetonitrile-water solution at a concentration of 10 mg / mL to obtain the DHB matrix. The performance of the CHCA matrix, DHB matrix, and MIL-100(Fe)-NH2 from Example 1 in pesticide detection by SALDI-TOF-MS was compared. The concentration of the pesticide standard solution (diluted with 70% (v / v) acetone-water solution) was 1 mg / mL. The results are as follows. Figure 8 As shown.

[0060] The above three matrices were used to detect the pesticide standards pyraclostrobin (AZ), triphenyl phosphate (TPP), and ethyl phosphonate sulfoxide (DS). TPP is typically used as an internal standard for pesticide detection. When CHCA ( Figure 8 When a1, b1, and c1 are used as matrices, SALDI-TOF-MS mass spectrometry exhibits numerous matrix-related background noises that interfere with the detection of analytes, such as [M+H]. + [M+Na] + and [M+K] + Use DHB ( Figure 8 When a2, b2, c2) are used as the matrix, the background noise is less than that of CHCA, but the signal intensity is lower. This may be because the crystallization of DHB with the analyte is uneven, and it cannot effectively transfer laser energy to promote the LDI process. Meanwhile, MIL-100(Fe)-NH2( Figure 8 When a3, b3, and c3 are used as matrices, mass spectrometry peaks with low background interference and high signal intensity are obtained. Less matrix effect avoids the suppression of analyte ionization and signal intensity.

[0061] To verify the performance of amino-modified MOF materials, pesticide concentrations of 1 mg / mL were analyzed using MIL-100(Fe) and MIL-100(Fe)-NH2 under the same conditions. The results are as follows: Figure 9 As shown, Figure 9 a1-c1 are SALDI-TOF-MS mass spectra of the pesticides azoxystrobin (AZ), benzalkonium chloride (BX), and monocrotophos (MCP) detected using MIL-100 (Fe) as the matrix. Figure 9a2-c2 are SALDI-TOF-MS mass spectra of the pesticides azoxystrobin (AZ), benzalkonium chloride (BX), and monocrotophos (MCP) using MIL-100(Fe)-NH2 as the matrix. Taking azoxystrobin (AZ) as an example, the SALDI-TOF-MS mass spectrum using MIL-100(Fe) as the matrix shows [AZ+Na]. + Signal strength is 1017, [AZ+K] + The signal strength is 1260. When using MIL-100(Fe)-NH2 as the matrix, [AZ+Na] + The signal strength increased to 72748, [AZ+K] + The value increased to 81411. This indicates that the modification with amino groups significantly improved the LDI process of MOFs, resulting in higher signal intensity.

[0062] To further investigate the feasibility of using amino-functionalized MIL-100(Fe)-NH2 to detect more pesticide compounds, we selected six pesticides for SALDI-TOF-MS testing in positive ion mode. Figure 10 As shown, Figure 10 a1–10a6 are SALDI-TOF-MS mass spectra of the pesticides azoxystrobin (AZ), indoxacarb (INX), triazophos (TZP), omethoate (OMT), chlorpyrifos sulfone (FSO2), and piperonyl butyl ether (PBO) detected using MIL-100(Fe)-NH2 as the matrix. This method successfully detected all pesticide standards at a concentration of 1 mg / mL with high signal intensity and low background interference. [M+Na] + and [M+K] + The peaks all exhibited high signal intensity, providing a solid foundation for quantitative analysis of real samples using SALDI-TOF-MS.

[0063] To verify the analytical performance of amino-functionalized MIL-100(Fe)-NH2 based on SALDI-TOF-MS in pesticide detection, linearity (R0.05) of 16 pesticides was determined using MIL-100(Fe)-NH2 as the matrix. 2 The limits of detection (LOD) and quantitation (LOQ) were determined. 10 ng / mL TPP was added as an internal standard to each standard solution to achieve accurate pesticide quantification. Standard curves were plotted based on the ionic strength of each pesticide standard and the ionic strength of TPP, and the results are shown in Table 1.

[0064] Table 1. SALDI-TOF-MS detection results of 16 pesticides

[0065]

[0066]

[0067] As shown in Table 1, the regression coefficients of all analytes were within the acceptable range of 0.90–0.99. The limits of quantitation and detection were 1.02–260.63 μg / L and 0.064–32.578 μg / L, respectively. The LOQs for 3-hydroxycarbofuran (HCF), ethionyl sulfoxide (DS), azoxystrobin (APE), and pyraclostrobin (AZ) reached 1.02 μg / L, and the signal-to-noise ratio (S / N) for all analytes was greater than or equal to 3. This demonstrates that the method for analyzing pesticides according to the present invention has high sensitivity and acceptable linearity.

[0068] Experimental Example 5: Detection of pesticide residues in environmental water samples

[0069] Actual water samples were collected from a certain region, and the MIL-100(Fe)-NH2 matrix was selected for quantitative analysis of pesticides. The water samples were prepared as test solutions according to Example 2, and detected by SALDI-TOF-MS (using the standard curve in Table 1). Components with excessively high concentrations were diluted before detection, and the results are shown in Table 2.

[0070] Table 2. Environmental water sample test results

[0071] name Concentration (μg / L) RSD (%) Benzene sulfoxide 6.2 8.0％ β-phosphite 7.2 5.8％ Piperyl Butyl Ether 48.2 1.3％

[0072] Quantitative analysis of environmental water samples revealed three pesticide compounds, with RSDs ranging from 1.3% to 8.0% across three replicate determinations. The results demonstrate that this method has high accuracy and can effectively and rapidly determine pesticide residues in actual water samples with simple pretreatment.

[0073] Experiment 6: Detection of Carbohydrates

[0074] Sugars are important metabolites in plants. Mannose (D-(+)-Mannose, CAS:3458-28-4, MW:180.16) and arabitol (L-(-)-Arabitol, CAS:7643-75-6, MW:152.15) are typical sugar components found in plants. Both sugars were dissolved in 80% (v / v) methanol aqueous solution to a concentration of 1 mg / mL and detected by SALDI-TOF-MS (other conditions were the same as in Example 2). The detection spectra are shown below. Figure 11 , Figure 12 As shown.

[0075] from Figure 11 , Figure 12It can be seen that both substances exhibited high signal intensity and low background interference during testing, thus proving that the amino-functionalized MIL-100(Fe) of the present invention can also be applied to the highly sensitive detection of sugars in the environment and plants.

[0076] The present invention has been further described above with reference to the embodiments. Those skilled in the art should understand that, without departing from the concept of the present invention, various specific parameters in the above embodiments can be changed or modified to form multiple specific embodiments, all of which are common variations of the present invention, and will not be described one by one here.

Claims

1. An amino-functionalized MIL-100(Fe), characterized in that, It is a complex of 3-amino-4,5-dihydroxybenzoic acid and MIL-100(Fe), wherein the mass ratio of 3-amino-4,5-dihydroxybenzoic acid to MIL-100(Fe) is 3:

8.

2. A method for preparing amino-functionalized MIL-100(Fe), characterized in that, The process includes the following steps: mixing MIL-100(Fe) and 3-amino-4,5-dihydroxybenzoic acid in water under stirring, followed by solid-liquid separation to obtain amino-functionalized MIL-100(Fe); the mass ratio of 3-amino-4,5-dihydroxybenzoic acid to MIL-100(Fe) is 3:

8.

3. The method for preparing amino-functionalized MIL-100(Fe) as described in claim 2, characterized in that, The reaction was carried out at room temperature for more than 1 hour.

4. The method for preparing amino-functionalized MIL-100(Fe) as described in claim 3, characterized in that, The corresponding water dosage for every 80 mg MIL-100 (Fe) is 20–30 mL.

5. The application of the amino-functionalized MIL-100(Fe) as described in claim 1 as a matrix in matrix-assisted laser desorption / ionization time-of-flight mass spectrometry.

6. The application as described in claim 5, characterized in that, The analyte is either a pesticide or a sugar.

7. The application as described in claim 6, characterized in that, The pesticides include one or more of the following: pyraclostrobin, chlorantraniliprole, indoxacarb, triazophos, benzyl sulfoxide, benzoxazine, chlorpyrifos sulfone, piperonyl butyl ether, phosmet, dimethoate, phorate, 3-hydroxycarbofuran, sulfoxide, oxadixyl, ethionyl sulfoxide, and benzyl sulfoxide.

8. The application as described in claim 6, characterized in that, The sugars include mannose and / or arabinose.

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