Aluminum-based metal-organic frameworks, fluorescent probes, methods, and applications

Abstract

The application relates to the technical field of metal organic framework materials, in particular to an aluminum-based metal organic framework material, a fluorescent probe, a method and application. The molecular structure of the aluminum-based metal organic framework material is as follows: {Al(BDC)} ∞ wherein BDC is terephthalic acid. The fluorescent probe is the metal organic framework material encapsulating 9,10-bisphenylacetylene anthracene and basic red 13. The aluminum-based metal organic framework material encapsulating 9,10-bisphenylacetylene anthracene and basic red 13 can generate fluorescence and has a three-emission platform, and can solve the problem of low accuracy when using a single fluorescent emission peak as a detection signal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal organic framework materials, in particular to an aluminum-based metal organic framework material, a fluorescent probe, a method and application. BACKGROUND

[0002] Metal organic framework (MOFs) is a kind of porous material, which is a periodic network structure formed by self-assembly of metal ions or metal clusters and organic ligands through coordination. Due to the high specific surface area, high porosity, uniform pore size distribution, diverse and adjustable structure composition, and special metal saturated or unsaturated active sites of metal organic framework materials, they have attracted widespread attention in the fields of adsorption separation, gas storage, catalysis and fluorescence detection.

[0003] Aluminum-based metal organic framework is a kind of porous material formed by self-assembly of aluminum ions or aluminum oxide clusters and organic ligands. Aluminum is one of the most abundant elements in the earth's crust, widely available and relatively low in price. Compared with other metal-based MOFs, aluminum-based MOFs have lower raw material cost, and aluminum has lower toxicity and less harm to the environment and human health. The coordination bond between aluminum and carboxylic acid ligand has high stability, which makes aluminum-based MOFs have good thermal stability and chemical stability. At the same time, many aluminum-based MOFs have large pore volume and high specific surface area, which enables them to provide a large number of adsorption sites and have high adsorption capacity for gases, organic small molecules and other substances.

[0004] SUMMARY

[0005] Therefore, the applicant constructs a new type of aluminum-based metal organic framework material with aluminum as the metal node, further encapsulates fluorescent dyes in the pores of the organic framework, and then produces fluorescence. In this way, the aluminum-based metal organic framework material can also be recognized when it interacts with some analytes, resulting in fluorescence enhancement or quenching, so as to realize effective detection of these analytes. For example, the aluminum-based metal organic framework material encapsulating 9,10-bisphenylacetylene anthracene and basic red 13 provided in the embodiments of the present application can produce fluorescence and has three emission platforms, which can solve the problem of low accuracy when using single fluorescence emission peak as a detection signal. At the same time, the aluminum metal cluster AlO4(OH)2 in the dye-encapsulated aluminum-based metal organic framework has a hydroxyl functional group extending to the pore direction, and the hydrogen atom on the hydroxyl group can form a strong hydrogen bond with the fluorine atom on the pesticide, thereby realizing specific recognition of fluorine-containing pesticides.

[0006] To this end, the embodiments of the present application disclose at least the following technical solutions:

[0007] In a first aspect, the embodiments disclose a metal organic framework material, the molecular structure of the metal organic framework material is: {Al(BDC)}∞ wherein BDC is terephthalic acid.

[0008] In some embodiments of the first aspect, the crystal structure of the aluminum-based metal organic framework material contains aluminum-based clusters AlO4(OH)2. In some embodiments, the aluminum-based clusters AlO4(OH)2have hydroxyl functional groups extending to the direction of the channel, and the hydrogen atoms on the hydroxyl groups can form strong hydrogen bonding with the fluorine atoms in flumioxazin and flufenoxuron, thereby achieving specific recognition of fluorine-containing pesticides.

[0009] In a second aspect, embodiments disclose a fluorescent probe, which is the metal organic framework material of the first aspect encapsulating 9,10-bisphenylacetylenyl anthracene and basic red 13.

[0010] In a third aspect, embodiments disclose a preparation method of the fluorescent probe of the second aspect. The preparation method comprises: dissolving aluminum chloride, terephthalic acid, 9,10-bisphenylacetylenyl anthracene, and basic red 13 in a solvent, and calcining at 90-110°C.

[0011] In some embodiments of the third aspect, the molar ratio of the aluminum chloride, terephthalic acid, 9,10-bisphenylacetylenyl anthracene, and basic red 13 is selected from 1:1:1:1, 1:2:1:1, 1:3:1:1, 2:1:1:1, 2:2:1:1, 2:3:1:1, 3:1:1:1, 3:2:1:1, or 3:3:1:1.

[0012] In some embodiments of the third aspect, the calcining time is 24-48h.

[0013] In some embodiments of the third aspect, the solvent is at least one of methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-diethylformamide, and water.

[0014] In a fourth aspect, embodiments disclose the use of the fluorescent probe of the second aspect or the fluorescent probe prepared by the preparation method of the third aspect in pesticide and metal cation detection.

[0015] In some embodiments of the fourth aspect, the pesticide is at least one of mesotrione, diflubenzuron, flonicamid, flumioxazin, ethyl chlornitrofen, 4-dichloroacetyl, glufosinate-ammonium, trichlorfon, glyphosate, acetamiprid, etoxmazole, flufenoxuron, abamectin, bifenox ethyl, triflumuron, thiamethoxam, nitenpyram, cyhalofop-butyl, aluminum trisethylphosphate, mesosulfuron-methyl.

[0016] In some embodiments of the fourth aspect, the metal ion is selected from Pb 2+ , Fe 3+ , Ba2+ Mg 2+ Mn 2+ Zr 4+ Na + Ca 2+ Al 3+ K + Zn 2+ Cu 2+ Co 2+ .

[0017] In a fifth aspect, the embodiments disclose a method for detecting flumioxazin or flutolanil. The method comprises: obtaining the fluorescent probe of the second aspect or the fluorescent probe prepared by the preparation method of the third aspect; mixing the fluorescent probe into a water sample to be detected, and detecting the content of flumioxazin or flutolanil in the water sample to be detected according to the fluorescence intensity of the mixed solution.

[0018] In a fifth aspect, the embodiments disclose a method for detecting Al 3+ or Fe 3+ . The method comprises: obtaining the fluorescent probe of the second aspect or the fluorescent probe prepared by the preparation method of the third aspect; mixing the fluorescent probe into a water sample to be detected, and detecting the content of Al 3+ or Fe 3+ in the water sample to be detected according to the fluorescence intensity of the mixed solution. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A schematic diagram of the crystal structure of the aluminum-based metal organic framework material provided in the embodiments. The sky blue octahedron represents an aluminum-based metal cluster AlO4(OH)2, the blue ball is Al, the red ball is O, and the black ball is C.

[0020] Figure 2 The infrared spectrograms of the aluminum-based metal organic framework material (MIL-53(Al)) and the fluorescent probe (BPEA / FG@MIL-53(Al)) provided in the embodiments.

[0021] Figure 3 The X-ray diffraction patterns of the aluminum-based metal organic framework material (MIL-53(Al), black) and the fluorescent probe (BPEA / FG@MIL-53(Al), red) provided in the embodiments.

[0022] Figure 4 The thermogravimetric analysis curve of the aluminum-based metal organic framework material (MIL-53(Al)) and the fluorescent probe (BPEA / FG@MIL-53(Al)) provided in the embodiments.

[0023] Figure 5The selective test results of the fluorescent probe provided for the examples on different solvents (water, methanol, ethanol, N, N-dimethylformamide, N, N-dimethylacetamide) are shown in the following table.

[0024] Figure 6 The selective test results of the fluorescent probe provided for the examples on different pesticides are shown in the following table. In the table, in turn, are blank, mesotrione, diflubenzuron, sulfoxaflor, flumioxazin, chlormequat chloride ethyl ester, 4-dichloroacetyl, glufosinate ammonium, trichlorfon, glyphosate, acetamiprid, etoxazole, flufenoxuron, abamectin, bifenox ethyl ester, triflumuron, thiamethoxam, nitenpyram, cyhalofop-butyl, triallethanol ammonium, mesosulfuron-methyl.

[0025] Figure 7 The interference test results of the fluorescent probe provided for the examples on the detection of flumioxazin (A) and flufenoxuron (B) under different interferents are shown in the following table.

[0026] Figure 8 The titration results of the fluorescent probe provided for the examples on the detection of different concentrations of flumioxazin or flufenoxuron are shown in the following table. (A) is the fluorescence curve under different concentrations of flumioxazin solution; (B) is the fitting curve of different concentrations of the fluorescent probe and I0 / I at the maximum wavelength in figure (A), I0 is the fluorescence intensity of the flumioxazin solution before titration, and I is the fluorescence intensity of the reaction solution after titration of the fluorescent probe solution and the flumioxazin solution; (C) is the fluorescence curve under different concentrations of flufenoxuron solution; (D) is the fitting curve of different concentrations of the fluorescent probe and I0 / I at the maximum wavelength in figure (A), I0 is the fluorescence intensity of the flufenoxuron solution before titration, and I is the fluorescence intensity of the reaction solution after titration of the fluorescent probe solution and the flufenoxuron solution.

[0027] Figure 9 The titration results of the fluorescent probe provided for the examples on the detection of different volume ratios of flumioxazin or flufenoxuron are shown in the following table. (a) is the fitting curve between X = 1 / (1 + [flumioxazin]) and (I0 / I) × X, X is the volume ratio of the probe solution and the flumioxazin titration solution; I0 is the fluorescence intensity of the flumioxazin solution before titration, I is the fluorescence intensity of the reaction solution after titration of the fluorescent probe solution and the flumioxazin solution, and [flumioxazin] is the concentration of the flumioxazin solution; (b) is the fitting curve between X = 1 / (1 + [flufenoxuron]) and (I0 / I) × X, X is the volume ratio of the probe solution and the flufenoxuron titration solution; I0 is the fluorescence intensity of the flufenoxuron solution before titration, I is the fluorescence intensity of the reaction solution after titration of the fluorescent probe solution and the flufenoxuron solution, and [flufenoxuron] is the concentration of the flufenoxuron solution.

[0028] Figure 10 The selective test results of the fluorescent probe provided for the examples on different metal ions are shown in the following table. In the table, in turn, are blank, Pb 2+ , Fe 3+ , Ba2+ Mg 2+ Mn 2+ Zr 4+ Na + Ca 2+ Al 3+ K + Zn 2+ Cu 2+ Co 2+ .

[0029] Figure 11 The fluorescence probe provided in the examples detects Al 3+ (a) and Fe 3+ (b) under different interference ions.

[0030] Figure 12 The titration results of the fluorescence probe provided in the examples for detecting different concentrations of Al 3+ or Fe 3+ ; (A) is the fluorescence curve under different concentrations of Al 3+ solution; (B) is the fitting curve of different concentrations of the fluorescence probe and I0 / I at the maximum wavelength in figure (a), I0 is the fluorescence intensity of the Al 3+ solution before titration, and I is the fluorescence intensity of the reaction solution after the fluorescence probe solution is titrated with the Al 3+ solution; (C) is the fluorescence curve under different concentrations of Fe 3+ solution; (D) is the fitting curve of different concentrations of the fluorescence probe and I0 / I at the maximum wavelength in figure (a), I0 is the fluorescence intensity of the Fe 3+ solution before titration, and I is the fluorescence intensity of the reaction solution after the fluorescence probe solution is titrated with the Fe 3+ solution.

[0031] Figure 13 The titration results of the fluorescence probe provided in the examples for detecting different volume ratios of Al 3+ or Fe 3+ ; (a) is the fitting curve between X=1 / (1+[Al 3+ ]) and (I0 / I)X, X is the volume ratio of the probe solution to the Al 3+ titration solution, I0 is the fluorescence intensity of the Al 3+ solution before titration, I is the fluorescence intensity of the reaction solution after the fluorescence probe solution is titrated with the Al 3+ solution, and [Al 3+ ] is the concentration of aluminum ions; (b) is the fitting curve between X=1 / (1+[Fe 3+ ]) and (I0 / I)X, X is the volume ratio of the probe solution to the Fe 3+ titration solution, I0 is the fluorescence intensity of the Fe 3+Fluorescence intensity in solution, I represents the fluorescence intensity of the fluorescent probe solution and Fe. 3+ Fluorescence intensity of the reaction solution after solution titration, [Fe 3+ [Icon concentration] represents the iron ion concentration. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. Reagents not specifically described in detail herein are all conventional reagents and are commercially available; methods not specifically described in detail are all conventional experimental methods and can be learned from the prior art.

[0033] Aluminum-based metals offer numerous advantages in constructing highly stable dye-encapsulated MOF fluorescence sensors. Firstly, Al... 3+ Aluminum-based MOFs can form strong coordination bonds with carboxylic acid ligands, maintaining structural stability in aqueous solutions, across a wide pH range, and even in various organic solvents. This is crucial for sensors operating in complex liquid environments (such as biological fluids and environmental water samples), preventing self-decomposition during operation. Secondly, aluminum-based MOFs typically possess high thermal decomposition temperatures, ensuring their reliability during various processing and handling procedures. Meanwhile, Al... 3+ It is a strong Lewis acid, which gives the inner surface of the pores of aluminum-based MOFs unsaturated coordination sites, and the strength of the coordination bonds is comparable to that of C / C covalent bonds. Through coordination, dye molecules are pre-anchored in the pores, enhancing their stability and dispersibility, and preventing dye leakage and aggregation. Furthermore, Al... 3+ It itself has d 10 The electronic configuration of aluminum-based MOFs typically does not introduce its own color or generate competitive absorption / emission, thus avoiding interference with the fluorescence signal of the encapsulated dye. This provides a "clean" platform for constructing high signal-to-noise ratio fluorescence sensors. Finally, the pore size and channel structure of aluminum-based MOFs can be precisely controlled by selecting organic ligands of different lengths and functions. This enables "tailor-made" encapsulation of dye molecules of specific sizes, ensuring that the dye is both securely embedded and in full contact with the target analyte.

[0034] This application discloses a metal-organic framework material (hereinafter named (MIL-53(Al))), the chemical structural formula of which is: {Al(BDC)} ∞ BDC is terephthalic acid.

[0035] In some embodiments of the first aspect, the crystal structure of the aluminum-based metal organic framework material contains an aluminum-based metal cluster AlO4(OH)2. In some embodiments, the aluminum-based metal cluster AlO4(OH)2has a hydroxyl functional group extending to the direction of the channel, and the hydrogen atom on the hydroxyl group can form a strong hydrogen bond with the fluorine atom in flumioxazin and diflubenzuron, thereby achieving specific recognition of fluorine-containing pesticides.

[0036] 9,10-Bisphenylethynyl anthracene (BPEA) is a neutral green emitter (λ_em≈510 nm) with large π-conjugated surface and rigid planar structure, which is sensitive to the polarity of microenvironment and suitable as a "signal reporter unit". Basic red 13 (FG) is a cationic azo dye with strong water solubility and almost no fluorescence itself, but has strong absorption in the range of 500-550 nm, which can be used as a "light absorption / energy regulation unit". The combination of the two theoretically has the potential to construct a green-red ratio signal, but BPEA is hydrophobic and bulky (about 1.5 nm long). Basic red 13 and 9,10-bisphenylethynyl anthracene differ greatly in polarity, charge, and solubility, making it difficult for them to exist stably in the same synthesis system, resulting in phase separation, competitive adsorption, or fluorescence quenching of the two in conventional solution or flexible matrix.

[0037] Current MOF encapsulation strategies are mostly single-molecule encapsulation (such as post-synthetic loading, one-step encapsulation, and in-situ polymerization). Most studies only encapsulate one dye, and for a dual-dye system, there is a lack of a general solvent system, a controllable loading ratio method, and a structure-property correlation model.

[0038] In addition, the azo group of FG may coordinate or charge transfer with the metal nodes (such as Al³⁺) of the MOF, leading to charge imbalance of the MOF framework and degradation or discoloration of the dye. The phenylacetylene group of BPEA has π-acidity, which may cause π-π stacking with the framework, leading to changes in molecular conformation and fluorescence intensity; when the two dyes coexist, they may synergistically induce distortion of the framework structure, leading to decreased crystal stability.

[0039] However, the {Al(BDC)} ∞ provided by the present application can simultaneously encapsulate BPEA and FG.

[0040] As shown in Figure 1 , the metal organic framework material is used to encapsulate 9,10-bisphenylethynyl anthracene (hereinafter referred to as BPEA) and basic red 13 (hereinafter referred to as FG), to obtain an "off-on" type fluorescent probe (hereinafter named BPEA / FG@MIL-53(Al)). The fluorescent probe can effectively realize the detection of pesticide residues (flumioxazin or diflubenzuron) and metal ions (Al 3+ or Fe3+ ) detection. And relative to BPEA and FG, the fluorescent probe has stronger adsorption performance, lower detection limit (the recognition detection limit of propynyl flurochlorisate is 0.12 μM, the recognition detection limit of flutolanil is 0.15 μM, the recognition detection limit of Al 3+ is 0.19 μM, and the recognition detection limit of Fe 3+ is 0.18 μM, which is significantly lower than the similar fluorescent probes in the prior art).

[0041] In addition, the fluorescence lifetime of BPEA is 15.26 ns, the fluorescence lifetime of FG is 0.21 ns, and the fluorescence lifetime of BPEA / FG@MIL-53(Al) is 7.38 ns, which means that there is a resonance energy transfer process from MIL-53(Al) to BPEA or FG. The fluorescent probe BPEA / FG@MIL-53(Al) obtained by encapsulating MIL-53(Al) has three emission peaks, which can effectively avoid the problem of low accuracy caused by single emission peak.

[0042] The embodiments also disclose a preparation method of the fluorescent probe. The preparation method comprises: dissolving aluminum chloride, terephthalic acid, 9,10-bisphenylacetylene anthracene, basic red 13 in a solvent, and calcining at 90-110 °C for 24-48 h.

[0043] In some embodiments, the reaction molar ratio of the aluminum chloride, the terephthalic acid, the 9,10-bisphenylacetylene anthracene and the basic red 13 is (1-3):(1-3):1:1, for example, the reaction molar ratio is selected from 1:1:1:1, 1:2:1:1, 1:3:1:1, 2:1:1:1, 2:2:1:1, 2:3:1:1, 3:1:1:1, 3:2:1:1 or 3:3:1:1.

[0044] In some embodiments, the solvent is at least one of methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-diethylformamide and water.

[0045] In one embodiment, the preparation method of the fluorescent probe comprises:

[0046] After a mixture of aluminum chloride (53 mg, 0.40 mmol), terephthalic acid (176 mg, 0.40 mmol), 9,10-bisphenylacetylene anthracene (151 mg, 0.40 mmol), basic red 13 (155 mg, 0.40 mmol) and N,N-dimethylformamide (8 mL) is stirred at room temperature for 30 min, it is transferred into a 25 mL autoclave, heated to 100 °C and kept for 36 h. The product is collected by centrifugation at 5 °C and 5000 r / min for 10 min, and then washed with deionized water for 3 times. -1The fluorescent probe was obtained by cooling the fluorescent probe at a cooling rate of 0.5 ℃ / min to room temperature, collecting the pink powder, washing with N,N-dimethylformamide and water for several times, and drying at ambient temperature. The yield was 72.5%.

[0047] Figure 2 The infrared spectrum of the fluorescent probe is shown. The blue color is the aluminiferous metal organic framework material (MIL-53(Al)), and the red color is the aluminiferous metal organic framework material encapsulating 9,10-bisphenylacetylenyl anthracene and basic red 13 (BPEA / FG@MIL-53(Al)). The peak at 3456 cm -1 corresponds to the isolated hydroxyl group, and the 3100-2800 cm -1 corresponds to the aromatic and aliphatic ν(C-H) vibration of the benzene ring, the 1660 cm -1 corresponds to N,N'-dimethylformamide, the 1400 cm -1 to 1600 cm -1 corresponds to the carboxylic acid group. The bands at 880 cm -1 , 780 cm -1 , 748 cm -1 and 650 cm -1 correspond to the bending vibration of OH and CH.

[0048] Figure 3 The X-ray diffraction pattern (PXRD) of the fluorescent probe is shown. The black color is the aluminiferous metal organic framework material (MIL-53(Al)), and the red color is the aluminiferous metal organic framework material encapsulating 9,10-bisphenylacetylenyl anthracene and basic red 13 (BPEA / FG@MIL-53(Al)). The two peak types are almost identical, proving that the dyes are successfully loaded in the material channels, and the MIL-53(Al) can still maintain the skeleton structure well.

[0049] Figure 4 The thermogravimetric analysis curve of the fluorescent probe is shown. The blue color is the aluminiferous metal organic framework material (MIL-53(Al)), and the red color is the aluminiferous metal organic framework material encapsulating 9,10-bisphenylacetylenyl anthracene and basic red 13 (BPEA / FG@MIL-53(Al)). The final weight loss rate of BPEA / FG@MIL-53(Al) is less than that of MIL-53(Al), meaning that the dyes are successfully loaded in the channels of the material.

[0050] In addition, the embodiment also discloses the application of the fluorescent probe or the fluorescent probe prepared by the preparation method of the third aspect in pesticide and metal ion detection.

[0051] In some embodiments, the pesticide is selected from at least one of mesotrione, diflubenzuron, sulfoxaflor, cloquintocet-mexyl, 4-dichloroacetyl, glufosinate-ammonium, trichlorfon, glyphosate, acetamiprid, etoxazole, flufenoxuron, abamectin, bifenox, triflumuron, thiamethoxam, nitenpyram, cyhalofop-butyl, triallethanol ammonium, mesosulfuron-methyl.

[0052] In addition, the embodiments also provide a method for detecting propargite or flufenoxuron. The method comprises: obtaining the fluorescent probe of the second aspect or the fluorescent probe prepared by the preparation method of the third aspect; mixing the fluorescent probe into a water sample to be detected, and detecting the content of propargite or flufenoxuron in the water sample to be detected according to the fluorescence intensity of the mixed solution. The method is simple and easy to operate, and has potential application value in monitoring pesticides in polluted water.

[0053] In some examples, the metal ion is selected from at least one of Pb 2+ , Fe 3+ , Ba 2+ , Mg 2+ , Mn 2+ , Zr 4+ , Na + , Ca 2+ , Al 3+ , K + , Zn 2+ , Cu 2+ , Co 2+ .

[0054] In addition, the embodiments also provide a method for detecting Al 3+ or Fe 3+ . The method comprises: obtaining the fluorescent probe of the second aspect or the fluorescent probe prepared by the preparation method of the third aspect; mixing the fluorescent probe into a water sample to be detected, and detecting the content of Al 3+ or Fe 3+ in the water sample to be detected according to the fluorescence intensity of the mixed solution. The method is simple and easy to operate, and has potential application value in monitoring pesticides in polluted water.

[0055] Some embodiments test the performance of BPEA / FG@MIL-53(Al):

[0056] 1. Selectivity test of different solvents

[0057] Method: DMF, DMA, methanol, ethanol or water are respectively used as solvents to prepare a probe solution with a concentration of 1×10 -5 mol / L of BPEA / FG@MIL-53(Al), and fluorescence spectrum test is respectively performed to determine the best solvent of the probe.

[0058] The results are shown in Figure 5 The solvent effect is the main factor determining the emission intensity of the probe. In the above several solvents, the maximum emission peak position of the probe is almost unchanged, and the different fluorescence intensities of the three emission peaks may be due to the interaction between the probe and the solvent. The maximum emission peak at 335 nm is from MIL-53(Al), the peak at 472 nm is from 9,10-bisphenylacetylene anthracene molecules, and the peak at about 600 nm is from basic red 13 molecules. Based on the maximum difference in fluorescence intensity of 9,10-bisphenylacetylene anthracene and basic red 13 in water and the advantage of water detection, water solution is determined as the best detection solvent.

[0059] 2. Selective test of different pesticides

[0060] Method: Prepare 10 -2 mol / L standard solutions of mesotrione, diflubenzuron, flonicamid, flumioxazin, chlomethoxynil ethyl, 4-dichloroacetyl, glufosinate, trichlorfon, glyphosate, acetamiprid, etoxazole, flufenoxuron, abamectin, bifenoxyl, triflumuron, thiamethoxam, nitenpyram, cyhalofop-butyl, triallethanol and mesosulfuron, respectively, with ultrapure water. Prepare a probe solution with a concentration of 1×10 - 5 mol / L of the fluorescent probe BPEA / FG@MIL-53(Al) with ultrapure water. Prepare multiple test samples by mixing the probe solution with different pesticide standard solutions in a volume ratio of 1:5, and mix equal volumes of ultrapure water and probe solution as a blank control. Detect the fluorescence spectrum in the wavelength range of 300-700 nm.

[0061] The results are shown in Figure 6 When the standard solution containing flumioxazin is detected, the fluorescence intensity is the largest between 450-550 nm; when the standard solution containing flufenoxuron is detected, the fluorescence intensity is the smallest between 450-550 nm. This shows that the fluorescence of the fluorescent probe BPEA / FG@MIL-53(Al) is significantly enhanced when combined with flumioxazin, and the fluorescence is significantly quenched when combined with flufenoxuron. Flumioxazin can activate the fluorescent probe to promote the enhancement of its fluorescence, and the activation is the largest; flufenoxuron can quench the fluorescence of the fluorescent probe, and the quenching is the largest, thereby indicating that the fluorescent probe provided by the present application has the strongest corresponding effect on flumioxazin and flufenoxuron, and can be applied to the detection of flumioxazin and flufenoxuron.

[0062] 3. Interference test of pesticides on the detection ability of the fluorescent probe BPEA / FG@MIL-53(Al)

[0063] Method: Prepare 10 -2mol / L of mesotrione, triflumuron, ethoxyfen, diflubenzuron, flonicamid, 4-dichloroacetyl, glufosinate, trichlorfon, acetamiprid, etoxazole, abamectin, mesosulfuron, thiamethoxam, cyhalofop-butyl, respectively. The standard solutions of flumioxazin and flufenacet were prepared with ultrapure water at a concentration of 10 -2 mol / L, respectively. The probe solution containing BPEA / FG@MIL-53(Al) fluorescent probe was prepared with ultrapure water at a concentration of 1×10 -5 mol / L.

[0064] For each interference solution, the probe solution was mixed with the interference solution at a volume ratio of 1:5, and then mixed with an equal volume of the standard solution. The fluorescence intensity of the final mixed solution at 480 nm was detected. At the same time, the fluorescence intensity of the mixed solution of the interference solution and the standard solution at a volume ratio of 1:5 was also detected as a control.

[0065] As shown in Figure 7 , when BPEA / FG@MIL-53(Al) was used to detect flumioxazin, it had a higher fluorescence intensity than the control group regardless of the addition of any of the above interference solutions. When BPEA / FG@MIL-53(Al) was used to detect flufenacet, it had a lower fluorescence intensity than the control group regardless of the addition of any of the above interference solutions. This indicates that the fluorescent probe provided by the present application has high sensitivity to flumioxazin or flufenacet and can resist any of the above interference substances.

[0066] 4. Titration detection of flumioxazin or flufenacet by BPEA / FG@MIL-53(Al) fluorescent probe

[0067] Method: 50 mL of standard solution containing flumioxazin or flufenacet at a concentration of 10 -2 mol / L was prepared with ultrapure water; the probe solution containing BPEA / FG@MIL-53(Al) fluorescent probe was prepared with ultrapure water at a concentration of 1×10 -5 mol / L. Different volumes of flumioxazin or flufenacet standard solution were added to the probe solution to prepare test solutions with different concentrations of flumioxazin or flufenacet. The fluorescence spectrum of the probe solution was detected in the wavelength range of 300 nm to 700 nm.

[0068] As shown in Figure 8 (A), when the concentration of the standard solution containing flumioxazin increased from 0.001 mM to 0.060 mM, the fluorescence intensity of the standard solution gradually increased.

[0069] As shown in Figure 8(B) shows the linear fitting curve of the Stern-Volmer equation, I0 / I = 1 + Ksv·[Q] wherein, I0 is the fluorescence intensity of the probe without titrant, [Q] is the concentration of the titrant, and Ksv is the slope of the equation, i.e. the fluorescence activation or quenching constant. As shown in Figure 8 (B), the fitting equation is y = -8.60x + 1.10, R 2 = 0.98, the fluorescence activation constant Ksv = -7.82 x 10 3 M -1 According to the calculation of LOD = 3σ / Ksv, the detection limit is 0.12 μM, indicating that the fluorescence probe provided by the application can not only quantitatively detect flumioxazin, but also has excellent sensitivity.

[0070] As shown in Figure 8 (C), when the concentration of the fluorine-containing phenylurea titrant increases from 0.001 mM to 1.000 mM, the fluorescence intensity of the titrant gradually decreases.

[0071] As shown in Figure 8 (D), the fitting equation is y = 5.06x + 0.58, R 2 = 0.96, the fluorescence activation constant Ksv = 1.15 x 10 2 M -1 , and the detection limit is calculated to be 0.15 μM, indicating that the fluorescence probe provided by the application can not only quantitatively detect flumioxazin, but also has excellent sensitivity.

[0072] 5. Test of the complexing ratio of the fluorescence probe represented by BPEA / FG@MIL-53(Al) and flumioxazin or fluorine phenylurea

[0073] Method: 50 mL of flumioxazin or fluorine phenylurea titrant with a concentration of 10 -2 mol / L was prepared; an ultrapure water solution was used to prepare a probe solution containing the fluorescence probe represented by BPEA / FG@MIL-53(Al) with a concentration of 1 x 10 -5 mol / L. The probe solution and the flumioxazin or fluorine phenylurea titrant were mixed in a volume ratio of 0.1 to 0.9 to prepare solutions with different proportions, and their fluorescence intensities at 480 nm were detected, respectively.

[0074] The Langmuir binding model can well reflect the binding of the fluorescence probe provided by the application and flumioxazin or fluorine phenylurea under different proportions. The curve is plotted with X = 1 / (1 + [Q]) as the abscissa and (I0-I)X as the ordinate, as shown in Figure 9The formula is shown. Among them, X is the propynyl fluroxypyr or flufeniure acetate titration solution according to the volume ratio; C is the constant related to the experimental system (such as the initial concentration of the probe, the characteristic constant of the binding reaction, etc., which needs to be defined in combination with specific experiments); K is the equilibrium constant of the binding process, reflecting the strength of the binding of the probe and propynyl fluroxypyr or flufeniure acetate, the larger K, the easier the binding occurs; [Q] is the concentration of propynyl fluroxypyr or flufeniure acetate; I0 is the fluorescence intensity of the fluorescence probe without propynyl fluroxypyr or flufeniure acetate; I is the fluorescence intensity of the system with propynyl fluroxypyr or flufeniure acetate.

[0075] As shown in the formula, in the system added with propynyl fluroxypyr or flufeniure acetate, the maximum emission intensity is 0.5 molar fraction, which indicates that the fluorescence probe BPEA / FG@MIL-53(Al) forms a complex with propynyl fluroxypyr or flufeniure acetate in a stoichiometric ratio of 1:1. Figure 9

[0076] 6. Detection of propynyl fluroxypyr or flufeniure acetate in actual water samples by the fluorescence probe BPEA / FG@MIL-53(Al)

[0077] Method: The fluorescence probe BPEA / FG@MIL-53(Al) was used to detect propynyl fluroxypyr or flufeniure acetate in actual samples. The Songhua River water was taken as an example, and the standard addition method was used for detection. The propynyl fluroxypyr or flufeniure acetate with concentrations of 0.2 μM, 2.0 μM, 20.0 μM, and 200.0 μM was added to the local water to detect propynyl fluroxypyr or flufeniure acetate.

[0078] The results are shown in Table 1 and Table 2, which lists the data for detecting propynyl fluroxypyr or flufeniure acetate, which means that the fluorescence probe BPEA / FG@MIL-53(Al) has excellent recovery rate when detecting propynyl fluroxypyr or flufeniure acetate in actual water samples, with a range of 94.0% to 100.6%, and the relative standard deviation calculated is within the range of 3.56%. The above data prove the accuracy and precision of the fluorescence probe BPEA / FG@MIL-53(Al) in detecting propynyl fluroxypyr or flufeniure acetate.

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083] 7. Selectivity test for different metal ions

[0084] Method: The ultrapure water was used to prepare Pb -2 2+ ​​, Fe 3+ , Ba 2+ , Mg 2+ , Mn 2+ , Zr 4+ , Na + , Ca 2+ , Al 3+ , K + , Zn 2+ , Cu 2+ , Co 2+ standard solution. The probe solution containing BPEA / FG@MIL-53(Al) shown in the fluorescence probe was prepared with an ultrapure water solution with a concentration of 1x10 -5 mol / L. The probe solution was prepared into multiple 10 mL test samples with different metal ion-containing standard solutions in a volume ratio of 1:5, and the probe solution was used as a control to detect the fluorescence spectrum in the wavelength range of 300 nm to 700 nm.

[0085] The results are shown in Figure 10 . When the Al 3+ -containing standard solution was detected, the fluorescence intensity was the strongest between 450 nm and 550 nm; when the Fe 3+ -containing standard solution was detected, the fluorescence intensity was the weakest between 450 nm and 550 nm. Thus, it is shown that the fluorescence probe BPEA / FG@MIL-53(Al) provided in the present application has a significantly enhanced fluorescence when combined with Al 3+ and a significantly quenched fluorescence when combined with Fe 3+ . Al 3+ can activate the fluorescence probe to promote the fluorescence enhancement, and the activation is the strongest; Fe 3+ can quench the fluorescence of the fluorescence probe, and the quenching is the strongest, thereby indicating that the fluorescence probe provided in the present application has the strongest corresponding effect on Al 3+ and Al 3+ , and can be applied to the detection of Al 3+ and Fe 3+ .

[0086] 8. Interference test of metal ions on the detection ability of BPEA / FG@MIL-53(Al) shown in the fluorescence probe

[0087] Method: ultrapure water was used to prepare 10 -2 mol / L of Pb 2+ , Ba 2+ , Mg 2+ , Zr 4+ , Na + , Ca 2 + , K + , Zn2+ , Mn 2+ , Cu 2+ , Co 2+ interference solution. The test solution with a concentration of 10 -2 mol / L Al 3+ or Fe 3+ was prepared with ultrapure water, respectively. The probe solution containing the fluorescent probe of BPEA / FG@MIL-53(Al) as shown was prepared with an ultrapure water solution with a concentration of 1×10 -5 mol / L.

[0088] For each interference solution, the probe solution was mixed with the interference solution at a volume ratio of 1:5, and then mixed with an equal volume of the test solution. The fluorescence intensity of the final mixed solution at 480nm was detected. Meanwhile, the mixture of the interference solution and the standard solution at a volume ratio of 1:5 was used as a control, and the fluorescence intensity of the mixture at 480nm was also detected.

[0089] As shown in Figure 11 , the fluorescent probe of BPEA / FG@MIL-53(Al) as shown was used to detect Al 3+ . Regardless of the addition of any of the above interference ions, it had a higher fluorescence intensity than the control group. The fluorescent probe of BPEA / FG@MIL-53(Al) was used to detect Fe 3 + , and regardless of the addition of any of the above interference ions, it had a lower fluorescence intensity than the control group. Thus, the fluorescent probe provided by the present application has a high sensitivity to Al 3+ or Fe 3+ , and can resist any of the above interference ions.

[0090] 9. Titration detection of Al 3+ or Fe 3+ by the fluorescent probe of BPEA / FG@MIL-53(Al) as shown

[0091] Method: 50mL of titration solution containing Al -2 or Fe 3+ with a concentration of 10 3+ mol / L was prepared with ultrapure water, respectively. The probe solution containing the fluorescent probe of BPEA / FG@MIL-53(Al) as shown was prepared with an ultrapure water solution with a concentration of 1×10 -5 mol / L. Different volumes of Al 3+ or Fe 3+ standard solution were added to the probe solution to prepare test solutions with different Al 3+ or Fe 3+ concentrations. The probe solution was used as a control, and the fluorescence spectrum was detected in the wavelength range of 300nm~700nm.

[0092] like Figure 12 As shown in (a), when Al is present 3+ When the concentration of the titrant was increased from 0.001 mM to 0.060 mM, the fluorescence intensity of the titrant gradually increased.

[0093] like Figure 12 As shown in (b), the fitted equation is divided into two segments, namely y1 = -0.58x + 0.61, with R1... 2 =0.52, Ksv1=-9.50×10 2 M -1 y² = -0.23x + 0.39, R² 2 =0.89, Ksv2=-6.15×10 2 M -1 Therefore, based on Ksv1 and Ksv2, the average detection limit was calculated to be 0.19 M, indicating that the fluorescent probe provided in this application can detect Al... 3+ It enables quantitative detection and has excellent sensitivity.

[0094] like Figure 12 As shown in (c), when Fe is present... 3+ When the concentration of the titrant is increased from 0.001 mM to 1.000 mM, the fluorescence intensity of the titrant gradually decreases.

[0095] like Figure 12 As shown in (d), the fitted equation is y = 16.10x + 0.52, R0 2 =0.99, fluorescence activation constant Ksv=3.12×10 4 M -1 Therefore, the detection limit was calculated to be 0.18 μM, indicating that the fluorescent probe provided in this application can detect Fe... 3+ It enables quantitative detection and has excellent sensitivity.

[0096] 10. The fluorescent probe shown in BPEA / FG@MIL-53(Al) and Al 3+ or Fe 3+ Complexation ratio test

[0097] Method: Prepare 50 mL of a 10% concentration... -2 mol / L Al 3+ or Fe 3+ The titration solution was prepared using ultrapure aqueous solution to contain BPEA / FG@MIL-53(Al) at a concentration of 1×10⁻⁶. -5 mol / L probe solution. Probe solution and Al 3+ or Fe 3+The titration solution was prepared in different proportions according to the volume ratio of 0.1 to 0.9, and the fluorescence intensity at 480 nm wavelength was detected respectively.

[0098] The Langmuir binding model can well reflect the fluorescence probe provided by the present application and Al 3+ or Fe 3+ The binding of urea under different proportions. The curve is drawn with X=1 / (1+[Q]) as the abscissa and (I0-I)X as the ordinate, as shown in Figure 9 The X is the probe solution and Al 3+ or Fe 3+ The titration solution is prepared according to the volume ratio; C is a constant related to the experimental system (such as the initial concentration of the probe, the characteristic constant of the binding reaction, etc., which needs to be defined in combination with specific experiments); K is the equilibrium constant of the binding process, reflecting the strength of the binding of the probe and Al 3+ or Fe 3+ The greater the K, the easier the binding occurs; [Q] is the Al 3+ or Fe 3+ Concentration; I0is the fluorescence intensity of the fluorescence probe without Al 3+ or Fe 3+ ; I is the fluorescence intensity of the system with Al 3+ or Fe 3+ .

[0099] As shown in Figure 13 , in the system with the addition of Al 3+ or Fe 3+ , the maximum emission intensity is 0.5 mole fraction, which indicates that the fluorescence probe represented by BPEA / FG@MIL-53(Al) forms a complex with Al 3+ or Fe 3+ with a stoichiometric ratio of 1:1.

[0100] 11、The fluorescence probe represented by BPEA / FG@MIL-53(Al) detects Al 3+ or Fe 3+

[0101] Method: The fluorescence probe represented by BPEA / FG@MIL-53(Al) is used to detect Al 3+ or Fe 3+ in the actual sample, taking Songhua River water as an example, the standard addition method is used for detection. The concentration of Al 3+ or Fe 3+ added to the local water is 0.2 μM, 2.0 μM, 20.0 μM, and 200.0 μM to detect Al 3+ or Fe 3+ .

[0102] Results are shown in Table 3 and Table 4, listing the data of detecting Al 3+ or Fe 3+ , which means that the fluorescent probe of BPEA / FG@MIL-53(Al) has excellent recovery rate in detecting Al 3+ or Fe 3+ in actual water samples, ranging from 92.5% to 101.4%, and the calculated relative standard deviation value is in the range of 3.29%. The above data prove the accuracy and precision of the fluorescent probe of BPEA / FG@MIL-53(Al) in detecting Al 3+ or Fe 3+ .

[0103] Table 3

[0104]

[0105] Table 4

[0106]

[0107] In summary, the fluorescent probe of BPEA / FG@MIL-53(Al) disclosed in the embodiment is a dye-encapsulated aluminum-based metal-organic framework "off-on" fluorescent probe, which can specifically recognize the pesticide propargite or diflubenzuron and metal ions Al 3+ or Fe 3+ , with detection limits of 0.12, 0.15, 0.19, and 0.18 μM, respectively, which are significantly lower than those of the same type of fluorescent probes in the prior art. In addition, the detection method adopted in the present application is simple and easy to operate, and has potential application value in monitoring pesticides or metal ions in polluted water.

[0108] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of or replace within the technical range disclosed in the present application, which should be covered within the protection scope of the present application.

Claims

1. A method of preparing a fluorescent probe, comprising: Aluminum chloride, terephthalic acid, 9,10-bisphenylacetylene anthracene, basic red 13 are dissolved in a solvent in a reaction molar ratio of (1-3):(1-3):1:1, and calcined at 90-110°C for 24-48h.

2. The preparation method according to claim 1, wherein the reaction molar ratio of aluminum chloride, terephthalic acid, 9,10-bisphenylacetylene anthracene, basic red 13 is selected from 1:1:1:1, 1:2:1:1, 1:3:1:1, 2:1:1:1, 2:2:1:1, 2:3:1:1, 3:1:1:1, 3:2:1:1 or 3:3:1:

1.

3. The preparation method according to claim 1, wherein the solvent is at least one of methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-diethylformamide and water.

4. The fluorescent probe obtained by the preparation method according to any one of claims 1-3, which is a metal-organic framework material encapsulating 9,10-bisphenylacetylene anthracene and basic red 13.

5. Use of the fluorescent probe obtained by the preparation method according to any one of claims 1-3 in detection of pesticides and metal cations.

6. Use according to claim 5, wherein the pesticide is at least one of mesotrione, diflubenzuron, sulfoxaflor, clofencet, fluridone, 4-dichloroacetyl, glufosinate, trichlorfon, glyphosate, acetamiprid, etoxazole, flufenoxuron, abamectin, bifenox, triflumuron, thiamethoxam, nitenpyram, cyhalofop-butyl, triallethanol ammonium, mesosulfuron-methyl; and the metal cation is at least one of Pb 2+ , Fe 3+ , Ba 2+ , Mg 2+ , Mn 2+ , Zr 4+ , Na + , Ca 2+ , Al 3+ , K + , Zn 2+ , Cu 2+ , Co 2 + .

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