阅读说明：本技术 一种铝金属有机骨架材料在黄曲霉毒素b1检测中的应用 (Application of aluminum metal organic framework material in aflatoxin B1 detection ) 是由 张三兵 王富祥 潘灿平 于 2021-09-15 设计创作，主要内容包括：本发明提供一种铝金属有机骨架材料在黄曲霉毒素B1检测中的应用。本发明依据黄曲霉毒素B1对铝金属有机骨架材料的荧光光谱影响,建立了一种非适体的、低成本的快速检测黄曲霉毒素B1的方法。所需要金属有机骨架材料在检测限优于现有金属有机骨架材料荧光检测黄曲霉毒素B1技术的情形下,用量仅为后者的1/1000；可通过调节铝金属有机骨架材料浓度实现对黄曲霉毒素B1的荧光增强或猝灭行为,且此现象具有良好的重复性。本发明提供的方法简单、灵敏、检测速度快、选择性高、成本低廉,可实现环境或食品中黄曲霉毒素B1的高选择性高灵敏分析检测。(The invention provides application of an aluminum metal organic framework material in aflatoxin B1 detection. According to the invention, a method for rapidly detecting aflatoxin B1 with low cost and without an aptamer is established according to the influence of aflatoxin B1 on the fluorescence spectrum of an aluminum metal organic framework material. Under the condition that the detection limit of the required metal organic framework material is superior to that of the existing metal organic framework material fluorescence detection aflatoxin B1 technology, the consumption of the metal organic framework material is only 1/1000 of the latter; the fluorescence enhancement or quenching behavior of the aflatoxin B1 can be realized by adjusting the concentration of the aluminum metal organic framework material, and the phenomenon has good repeatability. The method provided by the invention is simple and sensitive, has high detection speed, high selectivity and low cost, and can realize high-selectivity and high-sensitivity analysis and detection of aflatoxin B1 in environment or food.)

1. An application of an aluminum metal organic framework material in aflatoxin B1 detection.

2. The use according to claim 1, wherein the aluminum metal organic framework material is prepared from raw materials comprising: an aluminum compound, an organic ligand, and urea;

preferably, the aluminium compound is a hydrate of an aluminium salt, preferably aluminium chloride hexahydrate;

preferably, the organic ligand is an amino-substituted benzoic acid compound;

preferably, the benzoic acid compound comprises any one or a combination of at least two of terephthalic acid, phthalic acid, trimesic acid, pyromellitic acid, or biphenyldicarboxylic acid;

preferably, the organic ligand is 2-amino terephthalic acid;

preferably, the molar ratio of the aluminum compound, the organic ligand and the urea is (3-7): (5-15).

3. Use according to claim 1 or 2, wherein the aluminium metal organic framework material is prepared by a method comprising:

(a) dissolving an aluminum compound, mixing the aluminum compound with an organic ligand, dropwise adding a urea solution, mixing and stirring, and reacting in a high-pressure reaction kettle to obtain a primarily synthesized aluminum metal organic framework material;

(b) washing, primary dispersing, primary stirring, primary centrifugal collecting, secondary dispersing, secondary stirring, secondary centrifugal collecting and drying the primarily synthesized aluminum metal organic framework material in sequence to obtain the aluminum metal organic framework material;

preferably, in the step (a), the mixing and stirring time is 20-40 min;

preferably, in the step (a), the temperature of the reaction is 120-180 ℃, and the time of the reaction is 4-6 h;

preferably, in the step (b), deionized water is adopted for washing, and the washing times are more than 3 times;

preferably, in step (b), the primary dispersion solvent is dimethylformamide;

preferably, in step (b), the secondary dispersing solvent is methanol;

preferably, in the step (b), the primary stirring and the secondary stirring are both carried out in the dark, the temperature of the primary stirring and the temperature of the secondary stirring are respectively and independently 20-30 ℃, and the time of the primary stirring and the time of the secondary stirring are respectively and independently 20-30 h;

preferably, the drying is vacuum drying, the temperature of the vacuum drying is 40-60 ℃, and the time of the vacuum drying is 20-30 h.

4. Use according to any one of claims 1 to 3, characterized in that the method of detection comprises in particular the steps of:

(1) dispersing the aluminum metal organic framework material in a buffer solution to obtain a suspension of the aluminum metal organic framework material, and detecting the fluorescence signal intensity of the suspension;

(2) preparing a series of standard solutions of aflatoxin B1, mixing the standard solutions of aflatoxin B1 with a suspension of an aluminum metal organic framework material, and recording the change of an emission spectrum;

(3) and according to the curve fitted by the concentration of the aflatoxin B1 and the fluorescence intensity of the aluminum metal organic framework material, qualitative and/or quantitative detection can be carried out on the aflatoxin B1 in the sample according to the fluorescence signal and the working curve.

5. The use according to claim 4, wherein in step (1), the buffer solution is a phosphate buffer solution, preferably 0.005-0.02M phosphate buffer solution with pH 7.0-7.5;

preferably, in the step (1), the dispersion is ultrasonic dispersion, the power of the ultrasonic dispersion is 120-300W, and the time of the ultrasonic dispersion is 1-30 min;

preferably, in step (1), the concentration of the suspension of the aluminum metal organic framework material is 0.050 μ g/mL-0.050mg/mL, preferably 0.050 μ g/mL.

6. The use according to claim 4 or 5, wherein in step (1), the detection measures the emission spectrum at 360-560nm at an excitation wavelength of 300-360 nm.

7. The use according to any one of claims 4 to 6, wherein in step (2), the standard solution of aflatoxin B1 comprises: aflatoxin B1, methanol and phosphate buffer solution;

preferably, the mass ratio of the aflatoxin B1 to the methanol to the phosphate buffer solution is (0-1): (0-4): (15-20);

preferably, in step (2), the mixing is: mixing the suspension of the aluminum metal organic framework material with standard solutions of aflatoxin B1 with different concentrations to obtain solutions with the same volume and different aflatoxin B1 concentrations, incubating, and detecting the intensity of a fluorescence signal;

preferably, in the step (2), the incubation temperature is 20-30 ℃, and the incubation time is 0-40 min.

8. The use according to any one of claims 4 to 7, wherein in step (2), the reversible transition of fluorescence enhancement and quenching behavior of aflatoxin B1 is achieved by modulating the concentration of aluminum metal organic framework material;

preferably, in the step (2), the concentration of the aluminum metal organic framework material is 0.05-1 μ g/mL, so that the fluorescence enhancement of aflatoxin B1 is realized, and the concentration of the aluminum metal organic framework material is 1-50 μ g/mL, so that the fluorescence quenching of aflatoxin B1 is realized;

preferably, in step (2), the detection measures the emission spectrum of 360-560nm at the excitation light wavelength of 300-360nm, and preferably measures the emission spectrum of 360-560nm at the excitation light wavelength of 330 nm.

9. Use according to any one of claims 4 to 8, wherein in step (3) the fitted curve is plotted using the fluorescence intensity at emission wavelength 430-440nm, preferably at emission wavelength 435 nm.

10. The use according to any one of claims 1 to 9, wherein the aluminium metal organic framework material is used for the detection of aflatoxin B1 in food products;

preferably, the food product comprises any one of tea leaves, cereals, grain oils or dried fruits.

Technical Field

The invention relates to the technical field of pharmaceutical analysis, in particular to application of an aluminum metal organic framework material in aflatoxin B1 detection.

Background

Aflatoxins are bifuranosic ring toxoids produced by some strains of aspergillus flavus, aspergillus parasiticus and the like, are determined as class I carcinogens by international agency for research on cancer (IARC), have more than 20 derivatives, and can cause carcinogenesis, teratogenesis and mutagenesis to organisms at very low concentrations. The aflatoxin B1 is a most easily-produced and most toxic metabolite generated in the processes of harvesting, storing and processing of crop products, has high temperature resistance, and has stable chemical properties.

The current methods for detecting aflatoxin B1 include enzyme-linked immunosorbent assay, high performance liquid chromatography, membrane-based immunoassay, fluorimetry, and the like. Compared with other methods, the enzyme-linked immunosorbent assay has poorer recovery rate and relative standard deviation; the pretreatment of the high performance liquid chromatography is complex, the time consumption is long, and the sensitivity is low; membrane-based immunoassays require high pretreatment requirements and require accurate polarization readings. The fluorescence measurement method uses a fluorescent material (organic fluorescent dye or fluorescent nano material) as a signal platform, utilizes quenching and enhancing effects of the fluorescent nano material to further realize effective detection, and has the advantages of simplicity, sensitivity, easy operation, low cost and the like compared with other methods. Fluorescent nano-materials commonly used for detecting aflatoxin B1 include Carbon Dots (CDs), Quantum Dots (QDs), Metal Nanoclusters (MNC), luminescent metal organic framework materials and the like. However, in the fluorescent materials, the carbon dots have small volume and are difficult to separate and purify; the quantum dots and the metal nanoclusters have poor stability and low repeated utilization rate, and are usually combined with expensive and volatile aptamers, so that the search for a fluorescent material with low cost, non-aptamer assistance and excellent performance is very important.

The luminescent metal organic framework material is a porous crystal material which is composed of conjugated organic ligands and metal ions and has the luminescent characteristic, and has the advantages of high water stability, high thermal stability, high emission intensity, low cost and the like besides the characteristics of ultrahigh porosity, multiple functions, variable structures, large specific surface area and pore volume, uniform pore diameter and the like of the metal organic framework material. In recent years, researches show that the fluorescence method based on the luminescent metal organic framework material has the remarkable advantages of high sensitivity and selectivity on a detected object, quick response, real-time monitoring and the like. However, the existing aflatoxin B1 fluorescence detection methods based on the luminescent metal organic framework material are all fluorescence quenching type, so that the detection limit is relatively low, and the detection cost is high due to the large detection dosage of the luminescent metal organic framework material. The aluminum metal organic framework material has the advantages of being relatively cheap and convenient in preparation method, particularly the unique 'breathing effect' of the aluminum metal organic framework material can change the structure of the aluminum metal organic framework material under the external stimulation of pressure, temperature and object molecules, and provides possibility for adjusting the fluorescence property of the aluminum metal organic framework material.

CN111239213A discloses an in-situ modified electrode of a covalent organic framework material and an electrochemical biosensor, belonging to the field of electrochemical detection. The method takes ABA and En as connectors, and grows covalent organic framework material TpBD on the surface of a glassy carbon electrode in situ, so as to construct an electrode for in-situ covalent modification of TpBD, and the prepared TpBD bonded glassy carbon electrode is used as a working electrode to construct an electrochemical biosensor by introducing magnetic nanoparticles as a signal probe carrier and based on the specific binding action between an aptamer and aflatoxin M1. The electrochemical biosensor can be used for measuring aflatoxin M1 with high selectivity and high sensitivity, the detection limit is 0.15ng/mL, the stability is good, 76% of an initial signal can be still reserved after the aflatoxin M1 is stored for 15 days at room temperature, and the electrochemical biosensor can be widely applied to the electrochemical field.

CN110204654A discloses an aflatoxin surface imprinted polymer and application thereof in crop detection. Selecting a metal organic framework material HKUST-1 as a carrier, using 7-acetoxyl-4-methylcoumarin as a substitute template of aflatoxin, synthesizing a surface imprinted polymer HKUST-1, and combining with a high-efficiency liquid phase-fluorescence detector to separate, analyze and detect aflatoxin in wheat.

Therefore, the development of a fluorescence detection method of a probe with high sensitivity and high selectivity for aflatoxin B1 is the focus of research in the field.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the application of the aluminum metal organic framework material in aflatoxin B1 detection. The aluminum metal organic framework material is a fluorescent probe with high sensitivity and high selectivity identification on aflatoxin B1, so that the problems that the detection method of aflatoxin B1 in the prior art involves expensive instruments, complicated preparation steps or time cost are solved.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides an application of an aluminum metal organic framework material in aflatoxin B1 detection.

In the invention, under the condition that the detection limit of the aluminum metal organic framework material is superior to that of the existing technology for detecting aflatoxin B1 by using the metal organic framework material in fluorescence, the usage amount of the aluminum metal organic framework material is only 1/1000 of the latter, and the fluorescence detection method of the probe for high-sensitivity and high-selectivity identification of aflatoxin B1 is realized.

Preferably, the raw materials for preparing the aluminum metal organic framework material comprise: an aluminum compound, an organic ligand, and urea.

In the present invention, an aluminum metal organic framework material (MIL-53(Al) -NH) synthesized from an aluminum compound, an organic ligand and urea₂) Is a bistable system whose contraction and expansion depends on the guest molecule. Under aqueous environmental conditions, most pores exhibit narrow pores (np,) Morphology, few with macropores (lp, ) Morphology, so that aflatoxin B1 molecules can easily enter pores, and MIL-53(Al) -NH serving as molecular clamp₂The guest molecule aflatoxin B1 was clipped and the np pattern had more pores, resulting in enhanced fluorescence. In addition, the present inventors have surprisingly found that aluminum metal organic framework material (MIL-53(Al) -NH) can be adjusted₂) The reversible transformation of aflatoxin B1 to the fluorescence enhancement and quenching behaviors of aflatoxin B1 is realized at the concentration in a detection system, and the fluorescence detection method of the probe with high sensitivity and high selectivity for aflatoxin B1 is realized.

Preferably, the aluminium compound is a hydrate of an aluminium salt, preferably aluminium chloride hexahydrate.

Preferably, the organic ligand is an amino-substituted benzoic acid compound.

Preferably, the benzoic acid compound includes any one of terephthalic acid, phthalic acid, trimesic acid, pyromellitic acid, or biphenyldicarboxylic acid, or a combination of at least two thereof.

Preferably, the organic ligand is 2-amino terephthalic acid.

Preferably, the molar ratio of the aluminum compound, the organic ligand and the urea is (3-7): (5-15);

wherein the first "3-7" can be, for example, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, etc.;

wherein the second "3-7" can be, for example, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, etc.;

the "5 to 15" may be, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or the like.

Preferably, the aluminum metal organic framework material is prepared by the following preparation method:

(a) dissolving an aluminum compound, mixing the aluminum compound with an organic ligand, dropwise adding a urea solution, mixing and stirring, and reacting in a high-pressure reaction kettle to obtain a primarily synthesized aluminum metal organic framework material;

(b) and sequentially washing, primary dispersing, primary stirring, primary centrifugal collecting, secondary dispersing, secondary stirring, secondary centrifugal collecting and drying the primarily synthesized aluminum metal organic framework material to obtain the aluminum metal organic framework material.

Preferably, in step (a), the mixing and stirring time is 20-40min, such as 20min, 25min, 30min, 35min, 40min and the like.

Preferably, in step (a), the reaction temperature is 120-.

Preferably, in step (b), deionized water is used for washing, and the number of washing is more than 3, for example, 3, 4, 5, 6, etc.

Preferably, in step (b), the solvent for the primary dispersion is dimethylformamide.

Preferably, in step (b), the solvent for the secondary dispersion is methanol.

Preferably, in step (b), the first stirring and the second stirring are both carried out in the dark, the temperature of the first stirring and the second stirring is 20-30 ℃ respectively and independently, for example, 20 ℃, 22 ℃, 24 ℃, 26 ℃, 28 ℃, 30 ℃ and the like, and the time of the first stirring and the second stirring is 20-30h respectively and independently, for example, 20h, 22h, 24h, 26h, 28h, 30h and the like.

Preferably, the drying is vacuum drying, the temperature of the vacuum drying is 40-60 ℃, for example, 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃ and the like, and the time of the vacuum drying is 20-30h, for example, 20h, 22h, 24h, 26h, 28h, 30h and the like.

Preferably, in the detection of aflatoxin B1, the detection specifically comprises the following steps:

(1) dispersing the aluminum metal organic framework material in a buffer solution to obtain a suspension of the aluminum metal organic framework material, and detecting the fluorescence signal intensity of the suspension;

(2) preparing a series of standard solutions of aflatoxin B1, mixing the standard solutions of aflatoxin B1 with a suspension of an aluminum metal organic framework material, and recording the change of an emission spectrum;

(3) and according to the curve fitted by the concentration of the aflatoxin B1 and the fluorescence intensity of the aluminum metal organic framework material, qualitative and/or quantitative detection can be carried out on the aflatoxin B1 in the sample according to the fluorescence signal and the working curve.

Preferably, the buffer solution is a phosphate buffer solution, preferably a phosphate buffer solution of 0.005 to 0.02M (e.g., 0.005M, 0.01M, 0.015M, 0.02M, etc.) at a pH of 7.0 to 7.5 (e.g., 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, etc.).

Preferably, in the step (1), the dispersion is ultrasonic dispersion, the power of the ultrasonic dispersion is 120-300W, such as 120W, 140W, 160W, 180W, 200W, 220W, 240W, 260W, 280W, 300W, and the like, and the time of the ultrasonic dispersion is 1-30min, such as 1min, 5min, 10min, 15min, 20min, 25min, 30min, and the like.

Preferably, in step (1), the concentration of the suspension of the aluminum metal organic framework material is 0.050 μ g/mL-0.050mg/mL, and may be, for example, 0.050 μ g/mL, 0.100 μ g/mL, 0.500 μ g/mL, 0.001mg/mL, 0.005mg/mL, 0.010mg/mL, 0.050mg/mL, or the like, preferably 0.050 μ g/mL.

Preferably, the detection measures the emission spectrum at 360-.

Preferably, the standard solution of aflatoxin B1 comprises: aflatoxin B1, methanol and phosphate buffer solution.

Preferably, the mass ratio of the aflatoxin B1 to the methanol to the phosphate buffer solution is (0-1): (0-4): (15-20);

wherein "0 to 1" may be, for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1, etc. (the lower limit does not include 0);

wherein "0 to 4" may be, for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, etc. (the lower limit does not include 0);

the "15 to 20" may be, for example, 15, 16, 17, 18, 19, 20, or the like.

Preferably, in step (2), the mixing is: and mixing the suspension of the aluminum metal organic framework material with standard solutions of aflatoxin B1 with different concentrations to obtain solutions with the same volume and different aflatoxin B1 concentrations, incubating, and detecting the intensity of a fluorescence signal.

Preferably, in step (2), the incubation temperature is 20-30 ℃, for example, 20 ℃, 22 ℃, 24 ℃, 26 ℃, 28 ℃, 30 ℃ and the like, and the incubation time is 0-40min, for example, 0.01min, 0.05min, 0.1min, 0.5min, 1min, 2min, 4min, 6min, 8min, 10min, 20min, 30min, 40min and the like (excluding the lower limit of 0).

Preferably, in the step (2), the reversible transformation of fluorescence enhancement and quenching behaviors of the aflatoxin B1 is realized by modulating the concentration of the aluminum metal organic framework material.

Preferably, in step (2), the concentration of the aluminum metal organic framework material is 0.05-1 μ g/mL (e.g., can be 0.05 μ g/mL, 0.1 μ g/mL, 0.2 μ g/mL, 0.4 μ g/mL, 0.6 μ g/mL, 0.8 μ g/mL, 1 μ g/mL, etc.) to achieve fluorescence enhancement of aflatoxin B1, and the concentration of the aluminum metal organic framework material is 1-50 μ g/mL (e.g., can be 1 μ g/mL, 5 μ g/mL, 10 μ g/mL, 15 μ g/mL, 20 μ g/mL, 25 μ g/mL, 30 μ g/mL, 35 μ g/mL, 40 μ g/mL, 45 μ g/mL, 50 μ g/mL, etc.) to achieve fluorescence quenching of aflatoxin B1.

Preferably, in step (2), the detection measures the emission spectrum of 360-560nm at the excitation light wavelength of 300-360nm (for example, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, etc.), and preferably measures the emission spectrum of 360-560nm at the excitation light wavelength of 330 nm.

Preferably, the fitted curve is plotted using the fluorescence intensity at emission wavelengths 430-440nm (which may be 430nm, 432nm, 434nm, 435nm, 436nm, 438nm, 440nm, etc., for example), and preferably at emission wavelength 435 nm.

Preferably, the aluminum metal organic framework material is used for detecting aflatoxin B1 in food products.

Preferably, the food product comprises any one of tea leaves, cereals, grain oils or dried fruits.

Compared with the prior art, the invention has the following beneficial effects:

under the condition that the detection limit of the method is superior to that of the aflatoxin B1 fluorescence detection technology of other metal organic framework materials, the mass and the consumption are only 1/1000 of the latter; and the transformation of fluorescence enhancement or quenching behavior of the aflatoxin B1 can be realized by adjusting the concentration of the aluminum metal organic framework material. The aluminum metal organic framework material disclosed by the invention has good sensing capability on aflatoxin B1 in sensing application in detecting aflatoxin B1.

Drawings

Fig. 1 is a Stern-Volmer curve obtained for 0.050mg/mL of aluminum metal organic framework material at λ ex ═ 330 nm.

FIG. 2 is a standard curve of 0.050mg/mL aluminum metal organic framework material for detecting aflatoxin B1.

FIG. 3 shows the fluorescence quenching effect of aflatoxin B1 at different concentrations on a fluorescence spectrum of 0.050mg/mL aluminum metal organic framework material.

Fig. 4 is a Stern-Volmer curve obtained for 0.050 μ g/mL of aluminum metal organic framework material at λ ex ═ 330 nm.

FIG. 5 is a standard curve of 0.050. mu.g/mL aluminum metal organic framework material for detecting aflatoxin B1.

FIG. 6 shows the fluorescence enhancement effect of aflatoxin B1 at different concentrations on a fluorescence spectrogram of 0.050. mu.g/mL aluminum metal organic framework material.

FIG. 7 shows the response of different metal organic framework materials to aflatoxin B1.

FIG. 8 shows experimental data on interference of possible interferents in tea.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings. It should be understood by those skilled in the art that the specific embodiments are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Preparation example 1

The preparation example provides an aluminum metal organic framework material, which is prepared by the following preparation method:

(a) 1.448g of aluminum chloride hydrate (6mmol) were dissolved in deionized water, and 1.088g of 2-aminoterephthalic acid (6mmol) was added to the solution under magnetic stirring to give solution I. 0.576g of urea was dissolved in 10mL of deionized water to give solution II. Solution II was slowly added to solution I with continued stirring. Continuing stirring for 30min, transferring the mixed solution to a polytetrafluoroethylene-lined high-pressure reaction kettle, maintaining the temperature at 150 ℃ for 5h, and naturally cooling to room temperature;

(b) washing the primarily synthesized aluminum metal organic framework material with deionized water for 3 times, dispersing the aluminum metal organic framework material in 40mL of dimethylformamide, stirring the mixture for 24 hours at room temperature in the dark, centrifugally collecting the mixture, dispersing the mixture in 40mL of methanol, stirring the mixture for 24 hours at room temperature in the dark, centrifuging the mixture, collecting precipitates, drying the precipitates for 24 hours at 50 ℃ in vacuum, and grinding the precipitates for later use.

Preparation example 2

The preparation example provides an aluminum metal organic framework material, which is prepared by the following preparation method:

(a) 1.210g of aluminum chloride hydrate (5mmol) were dissolved in deionized water and 1.088g of 2-aminoterephthalic acid (6mmol) were added to the solution under magnetic stirring to give solution I. 0.576g of urea was dissolved in 10mL of deionized water to give solution II. Solution II was slowly added to solution I with continued stirring. Continuing stirring for 30min, transferring the mixed solution to a polytetrafluoroethylene-lined high-pressure reaction kettle, maintaining the temperature at 120 ℃ for 4h, and naturally cooling to room temperature;

(b) washing the primarily synthesized aluminum metal organic framework material with deionized water for 4 times, dispersing the aluminum metal organic framework material in 50mL of dimethylformamide, stirring the mixture for 24 hours at room temperature in the dark, centrifugally collecting the mixture, dispersing the mixture in 50mL of methanol, stirring the mixture for 24 hours at room temperature in the dark, centrifuging the mixture, collecting precipitates, drying the precipitates for 24 hours at 40 ℃ in vacuum, and grinding the precipitates for later use.

Preparation example 3

The preparation example provides an aluminum metal organic framework material, which is prepared by the following preparation method:

(a) 1.448g of aluminum chloride hydrate (6mmol) were dissolved in deionized water, and 0.907g of 2-aminoterephthalic acid (5mmol) was added to the above solution under magnetic stirring to give solution I. 0.576g of urea was dissolved in 10mL of deionized water to give solution II. Solution II was slowly added to solution I with continued stirring. Continuing stirring for 30min, transferring the mixed solution to a polytetrafluoroethylene-lined high-pressure reaction kettle, maintaining the temperature at 120 ℃ for 4h, and naturally cooling to room temperature;

(b) washing the primarily synthesized aluminum metal organic framework material with deionized water for 4 times, dispersing the aluminum metal organic framework material in 50mL of dimethylformamide, stirring the mixture for 24 hours at room temperature in the dark, centrifugally collecting the mixture, dispersing the mixture in 50mL of methanol, stirring the mixture for 24 hours at room temperature in the dark, centrifuging the mixture, collecting precipitates, drying the precipitates for 24 hours at 40 ℃ in vacuum, and grinding the precipitates for later use.

Preparation example 4

This preparation example provides an aluminum metal organic framework material, which differs from preparation example 1 only in that aluminum chloride hydrate is replaced with an equimolar amount of aluminum nitrate nonahydrate, and the other steps are the same as in preparation example 1.

Preparation example 5

This preparation example provides an aluminum metal organic framework material, which differs from preparation example 1 only in that 2-aminoterephthalic acid is replaced with an equimolar amount of terephthalic acid, and the other steps are the same as in preparation example 1.

Comparative preparation example 1

This comparative preparation example provides a zirconium metal organic framework material prepared by the following preparation method: stirring a mixed solution of 300mg of zirconium tetrachloride, 75 mu L of deionized water and 20mL of dimethylformamide for 15min, adding 235mg of 2-aminoterephthalic acid, 4.88g of benzoic acid, 347 mu L of hydrochloric acid and 10mL of dimethylformamide, stirring uniformly, transferring into a 100mL high-pressure reaction kettle, and reacting at 120 ℃ for 24 h. After the reaction was completed, it was cooled to room temperature. The dimethylformamide was washed 3 times and then 3 times with water. Dried overnight under vacuum at 50 ℃. Preparation gives light yellow Uio-66-NH₂A material.

Comparative preparation example 2

This comparative preparation example provides an iron metal organic framework material prepared by the following preparation method: 0.543g of 2-amino terephthalic acid was dissolved in 30mL of deionized water and subjected to ultrasonic treatment for 30 min. 0.8109g of ferric chloride hexahydrate were added to the above solution and sonicated again for 30 min. The mixed solution was transferred to a 50mL Teflon-lined autoclave and reacted at 150 ℃ for 6 hours. After cooling to room temperature, the resulting solid was collected by centrifugation and washed three times with deionized water and dimethylformamide, respectively. After washing, the solid is dispersed in absolute methanol and stirred for 24 h. Finally, the solid obtained by centrifugal collection is dried for 12 hours in vacuum at 70 ℃, and the MIL-53(Fe) -NH is obtained₂A material.

Example 1

Detection of aflatoxin B1 based on 0.050mg/mL aluminum metal organic framework material

In this embodiment, the aluminum metal organic framework material prepared in preparation example 1 is used to detect aflatoxin B1, and the specific method is as follows:

(1) dispersing 5mg of the aluminum metal organic framework material prepared in preparation example 1 in a 0.01M phosphate buffer solution with a ph of 10mL being 7.4, performing ultrasonic treatment for 5min to obtain a suspension of the aluminum metal organic framework material, and further diluting the suspension with the phosphate buffer solution to obtain a suspension with a material concentration of 0.055 mg/mL;

(2) dissolving 1mg of aflatoxin B1 into 5mL of methanol to obtain aflatoxin B1 mother liquor, diluting with phosphate buffer solution to obtain standard aflatoxin B1 solutions with different concentrations, and placing in a refrigerator (4 ℃) for later use; to 4.5mL of the suspension at 0.055mg/mL was added 0.5mL of standard aflatoxin B1 solution to give a series of 5mL volumes of solutions of different aflatoxin B1 concentrations. After incubation for 5min at room temperature, recording the fluorescence spectrum of the mixed solution in the range of 360nm to 560nm at the excitation wavelength of 330 nm;

(3) according to the concentration of the aflatoxin B1 and the fluorescence intensity fitting curve of the aluminum metal organic framework material, qualitative and quantitative detection can be carried out on the aflatoxin B1 in the sample according to the fluorescence signal and the working curve;

fig. 1 shows a Stern-Volmer curve of 0.050mg/mL aluminum metal organic framework material obtained under λ ex ═ 330nm, as shown in fig. 1, the curve first bends downward in a low concentration region, and after a certain concentration threshold value, the trend reverses.

Wherein, FIG. 2 is a standard curve for detecting aflatoxin B1 with 0.050mg/mL aluminum metal organic framework material, as shown in FIG. 2, the detected fluorescence signal and aflatoxin B1 concentration are linear within 0.96-16.01 μ M, and R is²0.9996 with a detection limit of 181ppb which is better than the 300ppb tolerance level of corn and peanut feed set by the U.S. Food and Drug Administration (FDA) for beef cattle;

wherein, fig. 3 shows the fluorescence quenching effect of aflatoxin B1 with different concentrations on a fluorescence spectrogram of 0.050mg/mL aluminum metal organic framework material, and as shown in fig. 3, when aflatoxin B1 is detected by using 0.050mg/mL aluminum metal organic framework material, the fluorescence spectrum of 0.050mg/mL aluminum metal organic framework material shows fluorescence quenching along with the increase of aflatoxin B1.

Example 2

Aflatoxin B1 detection based on 0.050 mu g/mL aluminum metal organic framework material

This example provides a method for detecting aflatoxin B1, which uses the aluminum metal organic framework material provided in preparation example 1, and differs from example 1 only in that, in step (1) and step (2), the concentration of the aluminum metal organic framework material is 0.050 μ g/mL, and the other steps are the same as example 1.

Wherein, fig. 4 is a Stern-Volmer curve obtained by 0.050 μ g/mL aluminum metal organic framework material under λ ex ═ 330nm, as shown in fig. 1, the curve extends straight line and is gradually bent after 9.61 μ M;

wherein, FIG. 5 is a standard curve for detecting aflatoxin B1 with 0.050 μ g/mL aluminum metal organic framework material, as shown in FIG. 5, the detected fluorescence signal and aflatoxin B1 concentration are linear within the range of 0.05-9.61 μ M, and R is²0.9987 with a detection limit of 11.67ppb, which is significantly better than the tolerance level of 300ppb set by the FDA for corn and peanut feeds for beef cattle, and is also lower than the maximum allowable content of 20ppb of aflatoxin B1 in food products currently prescribed in most countries and regions;

fig. 6 shows the fluorescence enhancement effect of aflatoxin B1 with different concentrations on a fluorescence spectrogram of an aluminum metal organic framework material of 0.050 μ g/mL, and as shown in fig. 6, when aflatoxin B1 is detected by the aluminum metal organic framework material of 0.050 μ g/mL, the fluorescence spectrum is gradually enhanced with the increase of aflatoxin B1, thereby showing that the fluorescence enhancement conversion of aflatoxin B1 can be realized by adjusting the concentration of the aluminum metal organic framework material.

Example 3

Detection of aflatoxin B1 by using different metal organic framework materials as sensing materials

In this embodiment, aflatoxin B1 was used to test the response of different metal-organic framework materials, and the operation steps were the same as those in embodiment 2 except that a certain aflatoxin B1 concentration was used and the metal-organic framework material was replaced; the reliability of this work was checked using a light-emitting metal-organic framework material (materials provided in preparations 1 to 5 and comparative preparations 1 to 2), each recording an initial intensity of I₀After adding the aflatoxin B of the same concentration for 15min, testing to be I;

the specific test results are shown in table 1 below:

TABLE 1

As can be seen from the test data in Table 1, the aluminum metal organic framework materials provided in preparations 1-4 are selective for aflatoxin B1, except that the material prepared after replacing the terephthalic acid ligand (preparation 5) is non-fluorescent; as can be seen from the comparison of preparation 1 with comparative preparations 1-2, other light-emitting metal-organic framework materials (Uio-66-NH) were used₂、MIL-53(Fe)-NH₂) The work was checked for reliability with an initial strength of I₀After the aflatoxin B15 min with the same concentration is added, a test shows that after comparison, the luminescent metal organic framework materials of other metal centers do not have great response to the aflatoxin B1.

Fig. 7 shows the response of different metal organic framework materials to aflatoxin B1, and it can be more clearly understood from the histogram that the luminescent metal organic framework material of the metal center of the present invention has a great response to aflatoxin B1.

Example 4

Detection of possible interferent in tea based on aluminum metal organic framework material as sensing material

The operation steps of the method are the same as those of the embodiment 2 except that aflatoxin B1 is replaced by a disturbing agent with a certain concentration to be mixed with the suspension of the aluminum metal organic framework material;

wherein, fig. 8 is interference experimental data of possible interferents in tea. As shown in fig. 8, even though the interferent concentration was 50 times aflatoxin B1 (50 times AFB1 except for ZEN concentration 10 times AFB 1), aluminum metal organic framework material still showed satisfactory selectivity. The results show that the aluminum metal organic framework material is a sensing material with good selectivity for fluorescence start detection of aflatoxin B1 in the aqueous phase.

Example 5

Aluminum metal organic framework material for detecting aflatoxin B1 in tea

The embodiment provides a sensing application of an aluminum metal organic framework material in detecting aflatoxin B1, and practical application examples thereof are as follows: the performance of the sensor provided in preparation example 1 was evaluated using tea leaves as a real sample, and the sensing application specifically included the following steps:

s1, the solid sample is first ground and then 0.5g of the solid sample is extracted with 4.5mL of phosphate buffer solution and vortexed for 30 min. Centrifuging at 12,000r/min for 10min, filtering the supernatant with 0.22 μm water system filter membrane, and diluting the filtrate with phosphate buffer solution by 50 times;

s2, preparing tea sample solutions added with aflatoxin B1 with different concentrations by adopting a standard addition method. And finally, detecting the sample according to the analysis process, adding 0.5mL of tea leaf sample or contaminated tea into 4.5mL of dispersion, incubating at room temperature for 5min, and recording the fluorescence spectrum of the mixed solution within the range of 360nm to 560nm at the excitation wavelength of 330 nm. For statistical purposes, all samples tested were in triplicate.

S3, adding aflatoxin B1 with different concentrations into a plurality of tea samples such as Junshan silver needle, Pu' er tea and the like respectively to determine the adding and recycling results;

as a result, it was found that: when 0.050mg/mL of aluminum metal organic framework material is used, under the addition concentrations of 0.5, 2 and 4mg/kg, the recovery rate of the method is between 85.19 and 99.25 percent, and the relative standard deviation is in the range of 1.31 to 6.36 percent; when 0.050 mu g/mL of aluminum metal organic framework material is used, the recovery rate of the method is between 78.86 and 115.29 percent and the relative standard deviation is in the range of 0.83 to 7.72 percent under the addition concentration of 0.02, 0.2, 1 and 2mg/kg, and the recovery experimental data can show that the method can be used for detecting the aflatoxin B1 in an actual sample.

The applicant states that the application of the aluminum metal organic framework material in the detection of aflatoxin B1 is illustrated by the above examples, but the invention is not limited to the above examples, i.e. it is not meant that the invention must rely on the above examples to be implemented. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.