Application of a ratio type aluminum-based metal-organic framework in detection of iron ions and / or ascorbic acid

Abstract

The application provides application of a ratio type aluminum-based metal organic framework material in detection of iron ions and / or ascorbic acid. The application establishes a fluorescent sensing platform for detecting iron ions and ascorbic acid with excellent selectivity and low cost. The method is based on a fluorescent method for detecting iron ions and ascorbic acid by using a luminescent metal organic framework material, and the phenomenon has good repeatability. The method provided by the application is simple, sensitive, fast in detection speed, high in selectivity, and low in cost, and can realize high-selectivity and high-sensitivity analysis and detection of iron ions in water samples and ascorbic acid in vitamin C effervescent tablets.

Description

Technical Field

[0001] This invention belongs to the technical field of chemical analysis, specifically relating to the application of a ratiometric aluminum-based metal-organic framework material in the detection of iron ions and / or ascorbic acid. Background Technology

[0002] Iron ions (Fe) 3+ Fe is one of the most widely used metal ions in agricultural and industrial processes, playing a vital role in biological systems by binding to various regulatory proteins. However, excessive intake of Fe can lead to problems. 3+ It can lead to age-related diseases, such as Alzheimer's disease and other neurogenic diseases. Human Fe 3+ Abnormal iron levels can lead to physiological damage. When the redox homeostasis of iron is disrupted, it can cause metabolic disorders and impair the body's immune mechanisms, leading to various diseases. Therefore, Fe... 3+ The detection of Fe in drinking water and the aquatic environment remains important. 3+ The detection of this substance is of great significance.

[0003] Ascorbic acid (AA), also known as vitamin C, is widely found in fresh fruits and plays a vital role in human growth, metabolism, and development. It maintains the formation of various tissues and mesenchymal cells, promotes growth and antibody formation, enhances immune activity, promotes collagen synthesis, and treats scurvy and anemia. However, excessive intake of ascorbic acid can lead to urinary tract stones, diarrhea, and stomach cramps. Therefore, simple and high-precision sensor detection of ascorbic acid is crucial for early control of ascorbic acid intake to prevent ascorbic acid-related diseases.

[0004] Iron ions and ascorbic acid (AA) are essential substances in living organisms, participating in various physiological processes. Therefore, establishing a rapid and simple method for simultaneous determination of Fe is crucial. 3+ The method of AA is particularly important.

[0005] Fluorescence detection is an economical, rapid, and convenient method with high selectivity and sensitivity. In recent years, fluorescence technology has become a cost-effective and highly promising detection method due to its advantages such as high sensitivity, easy visualization, simple operation, and fast sensing response. Among the various known fluorescence sensors reported to date, luminescent metal-organic frameworks (LMOFs) have attracted considerable attention. As a typical class of MOF materials, luminescent metal-organic frameworks possess more emission sites compared to traditional fluorescent materials. The multi-selectivity of their metal central ions and the modifiability of their organic ligands result in diverse structures and excellent physical and chemical properties, making them promising for the detection of iron ions and ascorbic acid. The metal ions and ligands of LMOFs can be modified and adjusted according to different requirements and purposes, enabling the construction of specific molecular recognition structures for analytes, thereby enhancing the specificity of the fluorescence sensor. Based on these advantages, we intend to use LMOFs for the detection of iron ions and ascorbic acid. However, a new problem arises: the influence of external conditions on the sensitivity of the fluorescence detection method. The emergence of ratiometric fluorescent probes solves these problems. They can overcome interference from instrument fluctuations, the surrounding environment, and probe concentration, improving the sensitivity and reliability of trace analysis.

[0006] Therefore, developing a fluorescent detection method for iron ions and ascorbic acid with highly sensitive and selective recognition and low cost is a key research focus in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide an application of a ratiometric aluminum-based metal-organic framework material in the detection of iron ions and / or ascorbic acid. The ratiometric aluminum-based metal-organic framework material is a fluorescent probe exhibiting high sensitivity and selectivity for recognizing iron ions and ascorbic acid.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides an application of a ratiometric aluminum-based metal-organic framework material in the detection of iron ions and / or ascorbic acid.

[0010] In this invention, the aluminum ratio-type aluminum-based metal-organic framework material is a fluorescent probe with high sensitivity and high selectivity for recognizing iron ions and ascorbic acid, thereby solving the problems of expensive instruments, complex preparation steps, or time costs involved in existing methods for detecting iron ions and / or ascorbic acid.

[0011] Preferably, the ratiometric aluminum-based metal-organic framework material is an aluminum-based metal-organic framework material modified with fluorescent dye monomers.

[0012] Preferably, the raw materials for preparing the ratiometric aluminum-based metal-organic framework material include: aluminum compounds, organic ligands, and fluorescent dye monomers.

[0013] Preferably, the aluminum compound is a hydrate of an aluminum salt, and more preferably aluminum chloride hexahydrate.

[0014] Preferably, the organic ligand is an amino-substituted benzoic acid compound, more preferably 2-aminoterephthalic acid.

[0015] Preferably, the fluorescent dye monomer includes any one or a combination of at least two of Rhodamine 6G, Rhodamine B, or Rhodamine, with Rhodamine B being the most preferred.

[0016] Preferably, the molar ratio of the aluminum compound, the organic ligand, and the fluorescent dye monomer is (1-5):(1-5):(0.05-0.2);

[0017] The first "1-5" can be, for example, 1, 1.5, 2, 2.5, 3, 4, 5, etc.

[0018] The second "1-5" can be, for example, 1, 1.5, 2, 2.5, 3, 4, 5, etc.

[0019] "0.05-0.2" can be, for example, 0.05, 0.1, 0.15, 0.2, etc.

[0020] Preferably, the ratiometric aluminum-based metal-organic framework material is prepared by the following method:

[0021] (a) Dissolve the organic ligand in an alkaline solution and sonicate to obtain an alkaline solution of the organic ligand; dissolve the aluminum compound in water and sonicate to obtain an aluminum compound solution.

[0022] (b) Add aluminum compound solution dropwise to the alkaline solution of the organic ligand, react to obtain a preliminarily synthesized metal-organic framework material, and then wash, centrifuge and dry in sequence to obtain an aluminum-based metal-organic framework material;

[0023] (c) After modifying the obtained aluminum-based metal-organic framework material with fluorescent dye monomers, the material is then washed, centrifuged and dried in sequence to obtain the ratio-type aluminum-based metal-organic framework material.

[0024] Preferably, in step (a), the power of the ultrasonic treatment is 200-300W, for example, it can be 200W, 210W, 220W, 230W, 240W, 250W, 260W, 270W, 280W, 290W, 300W, etc., and the ultrasonic treatment time is 5-10min, for example, it can be 5min, 6min, 7min, 8min, 9min, 10min, etc.

[0025] Preferably, in step (a), the molar ratio of the organic ligand to the solute in the alkaline solution is 1:(2-5), for example, it can be 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, etc.

[0026] Preferably, in step (a), the alkaline solution is an aqueous solution of sodium hydroxide.

[0027] Preferably, in step (b), the dripping rate is 1 to 2 drops / s, for example, 1 drop / s or 2 drops / s.

[0028] Preferably, in step (b), the reaction temperature is 20-35℃, for example, 20℃, 22℃, 30℃, 32℃, 35℃, etc., and the reaction time is 18-26h, for example, 18h, 19h, 20h, 22h, 23h, 24h, 25h, 26h, etc.

[0029] Preferably, in step (b), the washing process involves washing with deionized water at least three times, for example, three, four, or five times.

[0030] Preferably, in step (b), the centrifugation is performed at least 3 times, for example, 3 times, 4 times, 5 times, etc., the centrifugation speed is 2000-4000 rpm, for example, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, etc., and the centrifugation time is 2-4 minutes, for example, 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4 minutes, etc.

[0031] Preferably, in step (b), the drying is vacuum drying, the temperature of vacuum drying is 60-80℃, for example, 60℃, 65℃, 70℃, 75℃, 80℃, etc., and the vacuum drying time is 10-14h, for example, 10h, 11h, 12h, 13h, 14h, etc.

[0032] Preferably, in step (c), the specific steps of the modification are: mixing the aluminum-based metal-organic framework material, the fluorescent dye monomer, the crosslinking agent and the solvent, and then stirring.

[0033] Preferably, in the modification, the mass ratio of aluminum-based metal-organic framework material, fluorescent dye monomer and crosslinking agent is (30-70):(40-80):(50-100);

[0034] The first "30-70" can be, for example, 30, 40, 50, 60, 70, etc.

[0035] The second "40-80" can be, for example, 40, 50, 60, 70, 80, etc.;

[0036] The third "50-100" can be, for example, 50, 60, 70, 80, 100, etc.

[0037] Preferably, the crosslinking agent is 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxythiosuccinimide.

[0038] Preferably, the mass ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide to N-hydroxythiosuccinimide is (30-70):(10-30);

[0039] The first "30-70" can be, for example, 30, 40, 50, 60, 70, etc.

[0040] The second "10-30" can be, for example, 10, 15, 20, 25, 30, etc.

[0041] Preferably, in the modification, the stirring is magnetic stirring, the temperature is 20-35℃, for example, 20℃, 22℃, 24℃, 26℃, 30℃, 35℃, etc., and the time is 18-26h, for example, 18h, 20h, 22h, 24h, 26h, etc.

[0042] Preferably, in step (c), the washing process involves washing with deionized water at least three times, for example, three, four, or five times.

[0043] Preferably, in step (c), the centrifugation speed is 6000-9000 rpm, for example, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, etc., and the centrifugation time is 3-5 min, for example, 3 min, 3.5 min, 4 min, 4.5 min, 5 min, etc.

[0044] Preferably, in step (c), the drying is vacuum drying, the vacuum drying temperature is 60-80℃, for example, 60℃, 65℃, 70℃, 75℃, 80℃, etc., and the vacuum drying time is 10-14h, for example, 10h, 11h, 12h, 13h, 14h, etc.

[0045] Secondly, the present invention also provides a method for detecting iron ions and / or ascorbic acid using the ratio-type aluminum-based metal-organic framework material;

[0046] The substance to be detected is iron ions, and the detection method specifically includes the following steps:

[0047] (1) The ratio-type aluminum-based metal-organic framework material was dispersed in ultrapure water to obtain a suspension, and the fluorescence signal intensity was detected.

[0048] (2) Prepare a series of iron ion standard solutions, mix the iron ion standard solutions with the suspension in (1), and record the changes in the emission spectrum;

[0049] (3) Based on the fluorescence signal intensity fitting curve of the iron ion concentration and the ratio of the aluminum-based metal-organic framework material, the iron ions in the sample are qualitatively and / or quantitatively detected according to the fluorescence signal and the working curve.

[0050] The substance to be detected is ascorbic acid, and the detection method specifically includes the following steps:

[0051] (1') The ratio-type aluminum-based metal-organic framework material was dispersed in ultrapure water to obtain a suspension, and the fluorescence signal intensity was detected.

[0052] (2') Add iron ion solution to the suspension obtained in step (1), then add ascorbic acid standard solution of different concentrations, incubate, and record the changes in emission spectrum;

[0053] (3') Based on the fluorescence signal intensity fitting curve of the ratio of ascorbic acid concentration to the ratio of aluminum-based metal-organic framework material, the ascorbic acid in the sample is qualitatively and / or quantitatively detected according to the fluorescence signal and working curve.

[0054] Preferably, in steps (1) and (1'), the dispersion is ultrasonic dispersion, the dispersion power is 200-300W, for example, it can be 200W, 210W, 220W, 230W, 250W, 270W, 290W, 300W, etc., and the dispersion time is 3-7min, for example, it can be 3min, 4min, 5min, 6min, 7min, etc.

[0055] Preferably, in steps (1) and (1'), the concentration of the suspension of the ratiometric aluminum-based metal-organic framework material is 40-70 μg / mL, for example, it can be 40 μg / mL, 45 μg / mL, 50 μg / mL, 55 μg / mL, 60 μg / mL, 65 μg / mL, 70 μg / mL, etc.

[0056] Preferably, in steps (1) and (1'), the detection measures the emission spectrum of 370-660nm (e.g., 370nm, 380nm, 440nm, 480nm, 500nm, 560nm, 580nm, 600nm, 660nm, etc.) at an excitation wavelength of 310-360nm (e.g., 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, etc.).

[0057] Preferably, in step (2), the concentration of the iron ion standard solution is 0.5-400 μM, for example, it can be 0.5 μM, 1 μM, 5 μM, 10 μM, 50 μM, 100 μM, 150 μM, 200 μM, 300 μM, 400 μM, etc.

[0058] Preferably, the source of the iron ions is selected from any one or a combination of at least two of ferric chloride, ferric nitrate, or ferric sulfate, with ferric chloride being the preferred source.

[0059] Preferably, in step (2'), the concentration of the added iron ion solution is 10-60 μM, for example, it can be 10 μM, 20 μM, 30 μM, 40 μM, 50 μM, 60 μM, etc., and the concentration of the ascorbic acid standard solution is 0.1-50 μM, for example, it can be 0.1 μM, 10 μM, 20 μM, 30 μM, 40 μM, 50 μM, etc.

[0060] Preferably, in step (2'), the incubation temperature is 20-30℃, for example, 20℃, 23℃, 27℃, 29℃, 30℃, etc., and the incubation time is 1-40min, for example, 1min, 5min, 10min, 20min, 30min, 40min, etc.

[0061] Preferably, in steps (2) and (2'), the detection measures the emission spectrum of 370-660nm (e.g., 360nm, 420nm, 500nm, 560nm, 580nm, 640nm, 660nm, etc.) under an excitation wavelength of 310-360nm (e.g., 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, etc.), and more preferably, measures the emission spectrum of 370-660nm under an excitation wavelength of 340nm.

[0062] Preferably, in step (3), the fitting curve is plotted using the ratio of fluorescence intensity at emission wavelengths of 430-440nm (e.g., 430nm, 433nm, 436nm, 439nm, 440nm, etc.) to 575-595nm (e.g., 575nm, 585nm, 590nm, 595nm, etc.), and more preferably using the ratio of fluorescence intensity at emission wavelengths of 435nm and 585nm (denoted as P).

[0063] Preferably, in step (3'), the fitting curve is plotted using the ratio of fluorescence intensity at emission wavelengths of 440-450nm (e.g., 430nm, 433nm, 436nm, 439nm, 440nm, etc.) to 575-595nm (e.g., 575nm, 585nm, 590nm, 595nm, etc.), and more preferably using the ratio of fluorescence intensity at emission wavelengths of 443nm and 585nm (denoted as P).

[0064] Preferably, in step (3), the ratio of fluorescence intensity P is used to fit the curve; the working curve is specifically: the concentration of the standard solution of iron ions is used as the abscissa and P is used as the ordinate to perform curve fitting, and it is found that P has a good linear relationship with the concentration of iron ions.

[0065] Preferably, in step (3'), the ratio of fluorescence intensity P is used to fit the curve; the working curve is specifically: the concentration of the standard solution of ascorbic acid is used as the abscissa and P is used as the ordinate to perform curve fitting, and it is found that P has a good linear relationship with the concentration of ascorbic acid.

[0066] Preferably, the ratiometric aluminum-based metal-organic framework material is used in the detection of iron ions in water and in the detection of ascorbic acid in vitamin effervescent tablets and / or fruits.

[0067] Preferably, the source of the water includes any one of lakes, rivers, or tap water.

[0068] Preferably, the fruit includes apples and / or kiwifruit.

[0069] Preferably, the effervescent tablets include vitamin C effervescent tablets.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] This invention develops a ratiometric fluorescence sensing platform for the detection of iron ions and ascorbic acid with high selectivity and low cost. The method exhibits good repeatability. The method provided by this invention is simple, sensitive, fast, highly selective, and low-cost, enabling highly selective and sensitive analysis and detection of iron ions in water samples and ascorbic acid in fruits. The metal-organic framework material of this invention has excellent sensing capabilities for the detection of iron ions and ascorbic acid. Attached Figure Description

[0072] Figure 1 The emission spectra of the ratiometric fluorescence sensing platform with different iron ion concentrations provided in Example 1 are shown.

[0073] Figure 2 Fitting curves for the ratiometric fluorescence sensing platform at different iron ion concentrations provided in Example 1.

[0074] Figure 3 The emission spectra of the ratiometric fluorescence sensing platform at different ascorbic acid concentrations provided in Example 2 are shown.

[0075] Figure 4 Fitting curves for the ratiometric fluorescence sensing platform at different ascorbic acid concentrations provided in Example 2.

[0076] Figure 5 The response of the fluorescence sensing platform to iron ions at different reaction times.

[0077] Figure 6 For different Fe 3+ The response of the fluorescence sensing platform to ascorbic acid at different concentrations.

[0078] Figure 7 The response of the fluorescence sensing platform to ascorbic acid at different reaction times is shown.

[0079] Figure 8 The metal-organic framework materials provided in Examples 1-7 were used as sensing materials to assess their response to iron ions and ascorbic acid at the same concentration.

[0080] Figure 9 To compare the response of the metal-organic framework materials provided in Examples 1-2 as sensing materials to the same concentration of iron ions and ascorbic acid.

[0081] Figure 10 A fluorescence sensing platform for Fe in the presence of metal ions 3+ The selectivity.

[0082] Figure 11 The fluorescence sensing platform is selective for ascorbic acid in the presence of potential interfering substances. Detailed Implementation

[0083] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0084] Preparation Example 1

[0085] This preparation example provides a ratiometric aluminum metal-organic framework material, which is prepared by the following method:

[0086] (a) Dissolve 0.543 g of 2-aminoterephthalic acid (3 mmol) and 0.4 g of sodium hydroxide in 30 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 1; dissolve 0.724 g of aluminum chloride hexahydrate (3 mmol) in 20 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 2.

[0087] (b) Slowly add solution 2 to solution 1 and stir at room temperature for 24 hours to obtain a preliminary synthesized aluminum metal-organic framework material. Wash the preliminary synthesized metal-organic framework material with deionized water three times, collect the precipitate, and vacuum dry it at 70°C for 12 hours to obtain the metal-organic framework material. Grind it for later use.

[0088] (c) Disperse 50 mg of Rhodamine B (0.105 mmol) in 40 mL of ultrapure water, sonicate at 300 W for 5 min, add 50 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 20 mg of N-hydroxythiosuccinimide, stir for 15 min, add 50 mg of aluminum-based metal-organic framework material dispersed in 15 mL of water, stir magnetically at 30 °C for 24 h, wash three times with deionized water, centrifuge at 8000 rpm for 4 min, collect the precipitate, vacuum dry at 70 °C for 12 h to obtain ratiometric aluminum-based metal-organic framework material, grind for later use.

[0089] Preparation Example 2

[0090] This preparation example provides a ratiometric aluminum-based metal-organic framework material, which is prepared by the following method:

[0091] (a) Dissolve 0.543 g of 2-aminoterephthalic acid (3 mmol) and 0.4 g of sodium hydroxide in 30 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 1; dissolve 1.125 g of aluminum nitrate nonahydrate (3 mmol) in 20 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 2.

[0092] (b) Slowly add solution 2 dropwise into solution 1 and stir at room temperature for 24 hours to obtain a preliminarily synthesized aluminum metal-organic framework material; wash the preliminarily synthesized metal-organic framework material with deionized water 3 times, collect the precipitate, and dry it under vacuum at 70°C for 12 hours to obtain the metal-organic framework material, which is then ground for later use.

[0093] (c) Disperse 50 mg of Rhodamine B (0.105 mmol) in 40 mL of ultrapure water, sonicate at 300 W for 5 min, add 50 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 20 mg of N-hydroxythiosuccinimide, stir for 15 min, add 50 mg of metal-organic framework material dispersed in 15 mL of water, stir magnetically at 30 °C for 24 h, wash three times with deionized water, centrifuge at 8000 rpm for 4 min, collect the precipitate, vacuum dry at 70 °C for 12 h to obtain ratiometric aluminum-based metal-organic framework material, grind for later use.

[0094] Preparation Example 3

[0095] This preparation example provides a ratiometric aluminum-based metal-organic framework material, which is prepared by the following method:

[0096] (a) Dissolve 0.498 g of 1,3,5-pyromellitic acid (3 mmol) and 0.4 g of sodium hydroxide in 30 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 1. Dissolve 0.724 g of aluminum chloride hexahydrate (3 mmol) in 20 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 2.

[0097] (b) Slowly add solution 2 to solution 1 and stir at room temperature for 24 hours to obtain a preliminary synthesized aluminum metal-organic framework material; wash the preliminary synthesized metal-organic framework material with deionized water 3 times, collect the precipitate, and vacuum dry it at 70°C for 12 hours to obtain the metal-organic framework material, which is then ground for later use.

[0098] (c) Disperse 50 mg of Rhodamine B (0.105 mmol) in 40 mL of ultrapure water, sonicate at 300 W for 5 min, add 50 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 20 mg of N-hydroxythiosuccinimide, stir for 15 min, add 50 mg of metal-organic framework material dispersed in 15 mL of water, stir magnetically at 30 °C for 24 h, wash three times with deionized water, centrifuge at 8000 rpm for 4 min, collect the precipitate, vacuum dry at 70 °C for 12 h to obtain ratiometric aluminum-based metal-organic framework material, grind for later use.

[0099] Preparation Example 4

[0100] This preparation example provides a ratiometric aluminum metal-organic framework material, which is prepared by the following method:

[0101] (a) Dissolve 0.543 g of 2-aminoterephthalic acid (3 mmol) in 30 mL of ultrapure water and sonicate at 300 W for 10 min to determine solution 1; dissolve 0.724 g of aluminum chloride hexahydrate (3 mmol) in 20 mL of ultrapure water and sonicate at 300 W for 10 min to determine solution 2.

[0102] (b) Slowly add solution 2 to solution 1 and stir at room temperature for 24 hours to obtain a preliminary synthesized aluminum metal-organic framework material. Wash the preliminary synthesized metal-organic framework material with deionized water three times, collect the precipitate, and vacuum dry it at 70°C for 12 hours to obtain the metal-organic framework material. Grind it for later use.

[0103] (c) Disperse 50 mg of Rhodamine B (0.105 mmol) in 40 mL of ultrapure water, sonicate at 300 W for 5 min, add 50 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 20 mg of N-hydroxythiosuccinimide, stir for 15 min, add 50 mg of aluminum-based metal-organic framework material dispersed in 15 mL of water, stir magnetically at 30 °C for 24 h, wash three times with deionized water, centrifuge at 8000 rpm for 4 min, collect the precipitate, vacuum dry at 70 °C for 12 h to obtain ratiometric aluminum-based metal-organic framework material, grind for later use.

[0104] Preparation Example 5

[0105] This preparation example provides a ratiometric aluminum metal-organic framework material, which is prepared by the following method:

[0106] (a) Dissolve 0.543 g of 2-aminoterephthalic acid (3 mmol) and 0.2 g of sodium hydroxide in 30 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 1; dissolve 0.724 g of aluminum chloride hexahydrate (3 mmol) in 20 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 2.

[0107] (b) Slowly add solution 2 to solution 1 and stir at room temperature for 24 hours to obtain a preliminary synthesized aluminum metal-organic framework material. Wash the preliminary synthesized metal-organic framework material with deionized water three times, collect the precipitate, and vacuum dry it at 70°C for 12 hours to obtain the metal-organic framework material. Grind it for later use.

[0108] (c) Disperse 50 mg of Rhodamine B (0.105 mmol) in 40 mL of ultrapure water, sonicate at 300 W for 5 min, add 50 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 20 mg of N-hydroxythiosuccinimide, stir for 15 min, add 50 mg of aluminum-based metal-organic framework material dispersed in 15 mL of water, stir magnetically at 30 °C for 24 h, wash three times with deionized water, centrifuge at 8000 rpm for 4 min, collect the precipitate, vacuum dry at 70 °C for 12 h to obtain ratiometric aluminum-based metal-organic framework material, grind for later use.

[0109] Preparation Example 6

[0110] This preparation example provides a ratiometric aluminum metal-organic framework material, which is prepared by the following method:

[0111] (a) Dissolve 0.543 g of 2-aminoterephthalic acid (3 mmol) and 0.6 g of sodium hydroxide in 30 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 1; dissolve 0.724 g of aluminum chloride hexahydrate (3 mmol) in 20 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 2.

[0112] (b) Slowly add solution 2 to solution 1 and stir at room temperature for 24 hours to obtain a preliminary synthesized aluminum metal-organic framework material. Wash the preliminary synthesized metal-organic framework material with deionized water three times, collect the precipitate, and vacuum dry it at 70°C for 12 hours to obtain the metal-organic framework material. Grind it for later use.

[0113] (c) Disperse 50 mg of Rhodamine B (0.105 mmol) in 40 mL of ultrapure water, sonicate at 300 W for 5 min, add 50 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 20 mg of N-hydroxythiosuccinimide, stir for 15 min, add 50 mg of aluminum-based metal-organic framework material dispersed in 15 mL of water, stir magnetically at 30 °C for 24 h, wash three times with deionized water, centrifuge at 8000 rpm for 4 min, collect the precipitate, vacuum dry at 70 °C for 12 h to obtain ratiometric aluminum-based metal-organic framework material, grind for later use.

[0114] Preparation Example 7

[0115] This preparation example provides a ratiometric aluminum metal-organic framework material, which is prepared by the following method:

[0116] (a) Dissolve 0.543 g of 2-aminoterephthalic acid (3 mmol) and 0.4 g of potassium hydroxide in 30 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 1; dissolve 0.724 g of aluminum chloride hexahydrate (3 mmol) in 20 mL of ultrapure water, and sonicate at 300 W for 10 min to obtain solution 2.

[0117] (b) Slowly add solution 2 to solution 1 and stir at room temperature for 24 hours to obtain a preliminary synthesized aluminum metal-organic framework material. Wash the preliminary synthesized metal-organic framework material with deionized water three times, collect the precipitate, and vacuum dry it at 70°C for 12 hours to obtain the metal-organic framework material. Grind it for later use.

[0118] (c) Disperse 50 mg of Rhodamine B (0.105 mmol) in 40 mL of ultrapure water, sonicate at 300 W for 5 min, add 50 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 20 mg of N-hydroxythiosuccinimide, stir for 15 min, add 50 mg of aluminum-based metal-organic framework material dispersed in 15 mL of water, stir magnetically at 30 °C for 24 h, wash three times with deionized water, centrifuge at 8000 rpm for 4 min, collect the precipitate, vacuum dry at 70 °C for 12 h to obtain ratiometric aluminum-based metal-organic framework material, grind for later use.

[0119] Comparative Preparation Example 1

[0120] This comparative preparation example provides a zinc metal-organic framework material, which is prepared by the following method: 300 mg of zinc nitrate hexahydrate is dissolved in 10 mL of methanol, and 10.65 g of 2-methylimidazole is dissolved in 10 mL of methanol. Solution 1 is stirred for 4 h, then solution 2 is added, and stirring continues for 4 h. The mixture is washed three times with methanol and dried under vacuum at 50 °C overnight. ZIF-8 material is thus prepared.

[0121] Comparative Preparation Example 2

[0122] This comparative preparation example provides a europium metal-organic framework material, which is prepared by the following method: 44.6 mg Eu(NO3)3·6H2O (0.1 mmol) and 21 mg H3BTC (0.1 mmol) were dissolved in 10 mL of deionized water and 10 mL of ethanol, respectively, under stirring. The two solutions were then mixed and stirred vigorously at room temperature until a large amount of white precipitate formed. After stirring for 1 h, the synthesized white solid was collected by centrifugation. Finally, it was washed 6 times each with ethanol and water, and dried under vacuum at 50 °C overnight to obtain a white Eu-MOF material.

[0123] Example 1

[0124] A ratiometric fluorescence sensing platform for iron ion detection was built based on ratiometric aluminum-based metal-organic framework materials.

[0125] This embodiment uses the ratiometric aluminum-based metal-organic framework material prepared in Preparation Example 1 to detect iron ions. The specific method is as follows:

[0126] (1) 5 mg of the ratio-type aluminum-based metal-organic framework material prepared in Example 1 was dispersed in 10 mL of pure water at room temperature and sonicated at 300 W for 5 min to obtain a suspension of the ratio-type aluminum-based metal-organic framework material (500 μg / mL). The fluorescence spectrum of the mixed solution in the range of 370 nm to 660 nm was recorded under 340 nm excitation.

[0127] (2) Next, take 0.5 mL of the suspension (500 μg / mL) and add iron ions of different concentrations (as shown in Table 1 below), and make up to 5 mL. After incubating at room temperature for 5 minutes, record the fluorescence spectrum of the mixed solution in the range of 370 nm to 660 nm under 340 nm excitation.

[0128] Table 1

[0129]

[0130] in, Figure 1 For different Fe 3+ Emission spectra of ratiometric fluorescence sensing platforms at certain concentrations, such as Figure 1 As shown, with Fe 3 + As the concentration increases, the fluorescence intensity gradually decreases.

[0131] (3) According to Fe 3+ The concentration of Fe in the sample was fitted to the ratio of fluorescence intensity at 434 nm and 585 nm (defined as P) of the ratiometric fluorescence sensing platform. Based on the fluorescence signal and the working curve, the concentration of Fe in the sample could be determined. 3+ Perform quantitative detection;

[0132] Within the ranges of 1–20 μM and 20–70 μM, P and Fe 3+ The concentration showed a good linear relationship (R0). 2 =0.996). (e.g.) Figure 2 According to 3S b / K SV The detection limit for iron ions was calculated to be 0.36 μM / L, where S b The standard deviation of the blank signal (n=10).

[0133] Example 2

[0134] A ratiometric fluorescence sensing platform for ascorbic acid detection was built based on ratiometric aluminum-based metal-organic framework materials.

[0135] This embodiment uses the ratiometric aluminum-based metal-organic framework material prepared in Preparation Example 1 to detect ascorbic acid. The specific method is as follows:

[0136] (1) 5 mg of the ratio-type aluminum-based metal-organic framework material prepared in Example 1 was dispersed in 10 mL of pure water at room temperature and sonicated at 300 W for 5 min to obtain a suspension of the ratio-type aluminum-based metal-organic framework material (500 μg / mL). The fluorescence spectrum of the mixed solution in the range of 370 nm to 660 nm was recorded under 340 nm excitation.

[0137] (2) Next, take 0.5 mL of the suspension (500 μg / mL), add 20 μM iron ions, and then add different concentrations of AA (as shown in Table 2), and make up to 5 mL. After incubating at room temperature for 20 minutes, record the fluorescence spectrum of the mixed solution in the range of 370 nm to 660 nm under 340 nm excitation;

[0138] Table 2

[0139]

[0140] in, Figure 3 The emission spectra of the ratiometric fluorescence sensing platform are shown at different AA concentrations. The fluorescence intensity gradually increases with the increase of AA concentration.

[0141] (3) Based on the ratio of the concentration of ascorbic acid to the fluorescence intensity at 443 nm and 585 nm of the ratio of added iron ions (defined as P) fitting curve, ascorbic acid in the sample can be quantitatively detected based on the fluorescence signal and working curve.

[0142] Quantitative detection: such as Figure 4 As shown, within the range of 0.5–30 μM / L, P exhibits a good linear relationship with ascorbic acid concentration (R0). 2 =0.995). According to 3S b / K SV The limit of detection for ascorbic acid was calculated to be 0.31 μM / mL, where S b The standard deviation of the blank signal (n=10).

[0143] Example 3

[0144] Based on ratio-type aluminum-based metal-organic framework materials for Fe 3+ Optimize reaction conditions

[0145] This embodiment uses Fe 3+ The response of the metal-organic framework material prepared in Example 1 was tested, except that the incubation time was changed and the Fe was determined. 3+ Aside from the concentration (as shown in Table 3), the other operating steps were the same as in Example 1; this work was optimized using a ratiometric aluminum-based metal-organic framework material, and the initial fluorescence intensity ratio was recorded as P0. Fe was then added. 3+ The post-test result was P;

[0146] Table 3

[0147]

[0148] in, Figure 5 For different time-dependent fluorescence sensing platforms for Fe 3+The response was basically completed in about 5 minutes, so all subsequent experiments were conducted after 5 minutes of reaction.

[0149] Example 4

[0150] Based on ratiometric aluminum-based metal-organic framework materials, the reaction conditions for AA were optimized. In this embodiment, the response of the metal-organic framework material prepared in Preparation Example 1 was tested using ascorbic acid, except that Fe was replaced. 3+ The concentration and other operating procedures, except for the fixation of ascorbic acid, were the same as in Example 2 (Table 4); this work was optimized using a ratiometric aluminum-based metal-organic framework material, and the addition of Fe was recorded separately. 3+ The ratio of the initial fluorescence intensity after adding AA is P0, and the result after adding AA is P.

[0151] Table 4

[0152]

[0153]

[0154] in, Figure 6 The figure shows the response of iron ion concentration to AA. When the iron ion concentration is 20 μM, the fluorescence sensing platform has the best response to AA.

[0155] In this embodiment, the response of the metal-organic framework material prepared in Preparation Example 1 was tested using ascorbic acid. Except for changing the incubation time and maintaining a fixed AA concentration, the other operational steps were the same as in Example 2 (Table 5). This work was optimized using a ratiometric aluminum-based metal-organic framework material, and the addition of Fe was recorded. 3+ The ratio of the initial fluorescence intensity after adding AA is P0, and the result after adding AA is P.

[0156] Table 5

[0157]

[0158]

[0159] in, Figure 7 Due to the different time intervals, the response of the fluorescence sensing platform to AA was basically completed at around 20 minutes. Therefore, subsequent experiments were all measured after 20 minutes of reaction.

[0160] Example 5

[0161] Different metal-organic framework materials were used as sensing materials to detect iron ions and ascorbic acid.

[0162] In this embodiment, other metal-organic framework materials were used to respond to iron ions and ascorbic acid. For the detection of iron ions, the procedure was the same as in Example 1, except that a certain amount of iron ions were used instead of the metal-organic framework material. For the detection of ascorbic acid, the procedure was the same as in Example 2, except that a certain amount of ascorbic acid was used instead of the metal-organic framework material. The reliability of this work was verified using luminescent metal-organic framework materials (preparation examples 2-7, and materials provided in comparative preparation examples 1-2). The fluorescence intensity of the initial system was recorded as P0, and the fluorescence intensity after adding the same concentration of iron ions or ascorbic acid was recorded as P.

[0163] The specific test results are shown in Table 6 below:

[0164] Table 6

[0165]

[0166]

[0167] Preparation Example 3 showed no fluorescence, Preparation Example 6 showed no product formation, and when ascorbic acid was added, Preparation Examples 1-2 showed no fluorescence. Figure 8 and Figure 9 To illustrate the response of different metal-organic frameworks (MOFs) as sensing materials to the simultaneous detection of iron ions and ascorbic acid, the first column for each preparation example shows the raw materials, the second column shows the detection of iron ions, and the third column shows the detection of ascorbic acid. For iron ion detection, a lower P / P0 ratio indicates better performance, while for ascorbic acid detection, a higher P / P0 ratio indicates better performance. As shown in the figure, the ratiometric aluminum-based MOF synthesized in Preparation Example 1 exhibits the best simultaneous detection performance for iron ions and ascorbic acid, while other luminescent MOFs did not achieve a response superior to that of Preparation Example 1.

[0168] Example 5

[0169] Detecting potential interference based on ratiometric aluminum-based metal-organic framework materials as sensing materials.

[0170] In this embodiment, the response of the metal-organic framework material prepared in Preparation Example 1 was tested with possible interfering substances. First, the response of the ratiometric aluminum-based metal-organic framework material to various metal ions was tested.

[0171] in, Figure 9 The effect of metal ions (80 μM) on the fluorescence intensity of the material, such as Figure 9 As shown, Fe in metal ions 3+ It possesses the highest quenching efficiency. Other ions such as Mn... 2+ Cd 2+ Co 2+ Ba 2+ Zn 2+Ca 2+ Al 3+ Na + K + None of these factors affect the fluorescence intensity of the ratiometric aluminum-based metal-organic framework material, and the sensor provided by this invention still exhibits satisfactory selectivity.

[0172] in, Figure 10 To assess the selectivity of the fluorescence sensing platform for AA (20 μM / L) in the presence of potential interfering substances (200 μM), such as... Figure 10 As shown, the selectivity of the proposed method was tested by replacing ascorbic acid in the sensing platform with other analytes (valine, aspartic acid, isoleucine, glutamic acid, threonine, tryptophan, cysteine, sucrose, and fructose) at 10 times their concentration. Experiments revealed that even with interfering substances at 10 times the concentration of ascorbic acid, the sensor provided by this invention still exhibited satisfactory selectivity.

[0173] Example 6

[0174] Ratio-type aluminum-organic framework materials are used for the detection of iron ions in real samples.

[0175] This embodiment provides a sensing application of metal-organic framework materials in the detection of iron ions. A practical application example is as follows: using a water sample as the actual sample, the performance of the sensor provided in Preparation Example 1 was evaluated. The sensing application specifically includes the following steps:

[0176] S1. First, the water sample is passed through a 0.45um filter membrane, and then the filtrate is diluted.

[0177] S2. Following the analytical procedure, add 4.5 mL of water to 0.5 mL of dispersion, incubate at room temperature for 5 min, and then record the fluorescence spectrum of the mixed solution in the range of 370 nm to 660 nm under an excitation wavelength of 340 nm. For statistical purposes, all tested samples are in triplicate.

[0178] S3. Different concentrations of iron ions were added to different water samples, and the recovery results were determined.

[0179] The results showed that the method recovery rate was between 78.86% and 114.06% at spiking concentrations of 10 μM, 15 μM, and 30 μM, with a relative standard deviation of 0.83% to 7.72%. These recovery experimental data indicate that this method can be used for the detection of iron ions in water samples.

[0180] Example 7

[0181] Ratio-modulated aluminum-organic framework materials are used for the detection of ascorbic acid in real samples.

[0182] S1. First, dissolve the vitamin C effervescent tablets in water and dilute them to different concentrations to prepare dispersions of different concentrations.

[0183] S2. Following the analytical procedure, add 200 μL of iron ion solution and 4.3 mL of dispersion to 0.5 mL of the mixture. Incubate at room temperature for 20 min, then record the fluorescence spectrum of the mixed solution in the range of 370 nm to 660 nm under an excitation wavelength of 340 nm. For statistical purposes, all tested samples are in triplicate.

[0184] S3. Determine the vitamin C concentration in vitamin C effervescent tablets from different brands;

[0185] The results showed that the method recovered 80.12%–118.06% of vitamin C at concentrations of 5–20 μM, with relative standard deviations ranging from 1.50% to 8.69%. These recovery data indicate that the method can be used to detect ascorbic acid concentration in vitamin C samples.

[0186] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. The application of a ratiometric aluminum-based metal-organic framework material in the detection of iron ions and / or ascorbic acid, characterized in that, The raw materials for preparing the ratiometric aluminum-based metal-organic framework material include: aluminum compound, organic ligand, and fluorescent dye monomer; the molar ratio of the aluminum compound, organic ligand, and fluorescent dye monomer is (1-5):(1-5):(0.05-0.2); the aluminum compound is aluminum chloride hexahydrate and / or aluminum nitrate nonahydrate; the organic ligand is 2-aminoterephthalic acid; The ratio-type aluminum-based metal-organic framework material is prepared by the following method: (a) Dissolve the organic ligand in an alkaline solution and sonicate to obtain an alkaline solution of the organic ligand; dissolve the aluminum compound in water and sonicate to obtain an aluminum compound solution; the molar ratio of the organic ligand to the solute in the alkaline solution is 1:(2~4.5); the alkaline solution is an aqueous solution of sodium hydroxide and / or potassium hydroxide; (b) Add aluminum compound solution dropwise to the alkaline solution of the organic ligand, react to obtain a preliminarily synthesized metal-organic framework material, and then wash, centrifuge and dry in sequence to obtain an aluminum-based metal-organic framework material; the reaction temperature is 20-35℃ and the reaction time is 18-26 h; (c) After the aluminum-based metal-organic framework material is modified with a fluorescent dye monomer, it is washed, centrifuged and dried in sequence to obtain the ratio-type aluminum-based metal-organic framework material.

2. The application according to claim 1, characterized in that, The fluorescent dye monomer includes any one or a combination of at least two of Rhodamine 6G, Rhodamine B, or Rhodamine.

3. The application according to claim 2, characterized in that, The fluorescent dye monomer is Rhodamine B.

4. The application according to claim 1, characterized in that, In step (a), the power of the ultrasonic treatment is 200-300 W, and the ultrasonic treatment time is 5-10 min.

5. The application according to claim 1, characterized in that, In step (b), the dripping rate is 1~2 drops / s.

6. The application according to claim 1, characterized in that, In step (b), the washing process involves washing with deionized water at least three times.

7. The application according to claim 1, characterized in that, In step (b), the centrifugation is performed at least 3 times, with a centrifugation speed of 2000-4000 rpm and a centrifugation time of 2-4 min.

8. The application according to claim 1, characterized in that, In step (b), the drying is vacuum drying, the temperature of vacuum drying is 60-80℃, and the time of vacuum drying is 10-14 h.

9. The application according to claim 1, characterized in that, In step (c), the specific steps of the modification are as follows: mixing the aluminum-based metal-organic framework material, the fluorescent dye monomer, the crosslinking agent and the solvent, and then stirring.

10. The application according to claim 9, characterized in that, In the modification, the mass ratio of aluminum-based metal-organic framework material, fluorescent dye monomer and crosslinking agent is (30-70):(40-80):(50-100).

11. The application according to claim 9, characterized in that, The crosslinking agent is 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N -Hydroxythiosuccinimide.

12. The application according to claim 11, characterized in that, The 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N The mass ratio of 3-hydroxythiosuccinimide is (30-70):(10-30).

13. The application according to claim 9, characterized in that, In the modification, the stirring is magnetic stirring, the temperature is 20-35℃, and the time is 18-26 h.

14. The application according to claim 1, characterized in that, In step (c), the washing process involves washing with deionized water at least three times.

15. The application according to claim 1, characterized in that, In step (c), the centrifugation speed is 6000-9000 rpm and the centrifugation time is 3-5 min.

16. The application according to claim 1, characterized in that, In step (c), the drying is vacuum drying, the temperature of vacuum drying is 60-80℃, and the time of vacuum drying is 10-14 h.

17. The application according to claim 1, characterized in that, The detection method specifically includes the following steps: (1) The ratio-type aluminum-based metal-organic framework material was dispersed in ultrapure water to obtain a suspension, and the fluorescence signal intensity was detected. (2) Prepare a series of iron ion standard solutions, mix the iron ion standard solutions with the suspension in (1), and record the changes in the emission spectrum; (3) Based on the fitting curve of the concentration of iron ions and the fluorescence signal intensity of the ratio-type aluminum-based metal-organic framework material, the iron ions in the sample are qualitatively and / or quantitatively detected according to the fluorescence signal and working curve.

18. The application according to claim 1, characterized in that, The detection method specifically includes the following steps: (1') The ratiometric aluminum-based metal-organic framework material was dispersed in ultrapure water to obtain a suspension, and the fluorescence signal intensity was detected. (2') Add iron ion solution to the suspension obtained in step (1), then add ascorbic acid standard solutions of different concentrations, incubate, and record the changes in emission spectrum; (3') Based on the fitting curve of the concentration of ascorbic acid and the fluorescence signal intensity of the ratio-type aluminum-based metal-organic framework material, the ascorbic acid in the sample is qualitatively and / or quantitatively detected according to the fluorescence signal and working curve.

19. The application according to claim 17 or 18, characterized in that, In steps (1) and (1'), the dispersion is ultrasonic dispersion, the dispersion power is 200-300 W, and the dispersion time is 3-7 min.

20. The application according to claim 17 or 18, characterized in that, In steps (1) and (1'), the concentration of the suspension of the ratiometric aluminum-based metal-organic framework material is 40-70 µg / mL.

21. The application according to claim 17 or 18, characterized in that, In steps (1) and (1'), the detection measures the emission spectrum of 370-660 nm at an excitation wavelength of 310-360 nm.

22. The application according to claim 17, characterized in that, In step (2), the concentration of the iron ion standard solution is 0.5-400 μM.

23. The application according to claim 17, characterized in that, The source of the iron ions is selected from any one or a combination of at least two of ferric chloride, ferric nitrate, or ferric sulfate.

24. The application according to claim 23, characterized in that, The iron ions are derived from ferric chloride.

25. The application according to claim 18, characterized in that, In step (2'), the concentration of the added iron ion solution is 10-60 μM, and the concentration of the ascorbic acid standard solution is 0.1-50 μM.

26. The application according to claim 18, characterized in that, In step (2'), the incubation temperature is 20-30℃ and the incubation time is 1-40 min.

27. The application according to claim 17 or 18, characterized in that, In steps (2) and (2'), the detection measures the emission spectrum of 370-660 nm at an excitation wavelength of 310-360 nm.

28. The application according to claim 27, characterized in that, In steps (2) and (2'), the detection measures the emission spectrum of 370-660 nm at an excitation wavelength of 340 nm.

29. The application according to claim 17, characterized in that, In step (3), the fitting curve is plotted using the ratio of fluorescence intensity at emission wavelengths of 430-440 nm to 575-595 nm.

30. The application according to claim 29, characterized in that, In step (3), the fitting curve is plotted using the ratio of fluorescence intensity at emission wavelengths of 435 nm and 585 nm.

31. The application according to claim 18, characterized in that, In step (3'), the fitting curve is plotted using the ratio of fluorescence intensity at emission wavelengths of 440-450 nm to 575-595 nm.

32. The application according to claim 31, characterized in that, In step (3'), the fitting curve is plotted using the ratio of fluorescence intensity at emission wavelengths of 443 nm and 585 nm.

33. The application according to claim 1, characterized in that, The application of the ratiometric aluminum-based metal-organic framework material in the detection of iron ions in water and in the detection of ascorbic acid in vitamin effervescent tablets and / or fruits.

34. The application according to claim 33, characterized in that, The water source can be any one of lakes, rivers, or tap water.

35. The application according to claim 33, characterized in that, The fruits include apples and / or kiwifruit.

36. The application according to claim 33, characterized in that, The effervescent tablets include vitamin C effervescent tablets.

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