Detection method for aflatoxin b1 based on NH2-MIL-53 (AL)

Abstract

To provide a method for detecting aflatoxin B1 based on NH2-MIL-53(Al), in the technical field of aflatoxin detection.SOLUTION: NH2-MIL-53(Al) is a yellow solid obtained by dissolving AlCl3 6H2O in ultrapure water, adding NH2-BDC while stirring, then adding an urea aqueous solution while stirring, keeping at 150°C for 5 hours, and naturally cooling to the room temperature. The prepared NH2-MIL-53(Al) has good sensitivity and selectivity to AFB1, and a portable flexible sensor is prepared by loading a fluorescent probe onto an electrostatic spinning nanofiber thin film. The successful combination of the flexible sensor and the smart phone greatly reduces a detection cost and time, and provides a promising method for qualitative identification and quantitative detection of the field AFB1 at the site.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention belongs to the technical field of detecting aflatoxins, and in particular to a method for detecting aflatoxin B1 based on NH2-MIL-53(Al). [Background technology]

[0002] Aflatoxin B1 (AFB1) is the most harmful and common mycotoxin, and there is a need to establish an economical, sensitive, simple and rapid method for detecting AFB1.

[0003] At present, the methods for detecting AFB1 mainly include enzyme-linked immunosorbent assay, high-performance liquid chromatography, membrane flow immunoassay, immunoassay chromatography and electrochemical methods. Chromatography has a high detection sensitivity for AFB1, but it is expensive, has a complicated sample preparation process, and has high technical requirements for users. Immunoassay chromatography incorporates biomolecules, which makes this method less robust. These methods also have common drawbacks, such as expensive equipment, complicated and time-consuming operation. These drawbacks may limit the widespread use of these methods in developing countries. Luminescent metal-organic frameworks (LMOFs) as a new type of chemical sensor have attracted attention due to their advantages such as high sensitivity, good substrate selectivity, good reproducibility, and simple equipment. To date, there have been several reports on the use of sensors based on MOFs for the detection of AFB1. However, the sensing mechanism of these sensors is luminescence quenching (i.e., fluorescence quenching), which is generally called "off" sensing, which lacks the advantages of sensors operating based on the luminescence "on" principle, such as excellent sensitivity, selectivity and practicality. Therefore, it is more meaningful and in high demand to develop a robust and efficient MOF-based fluorescent “on” sensor for AFB1 detection. [Summary of the Invention] [Means for solving the problem]

[0004] In view of the problems existing in the prior art, the present invention aims to provide a method for detecting aflatoxin B1 based on NH2-MIL-53(Al).

[0005] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0006] The method for preparing NH2-MIL-53 is as follows: (1) Dissolve AlCl3·6H2O in ultrapure water, add NH2-BDC while stirring, and stir to obtain "Solution 1"; (2) dissolving urea in ultrapure water to obtain "solution 2"; (3) slowly adding "Solution 2" to "Solution 1" with continuous stirring, stirring uniformly, maintaining at 150°C for 5 hours, and then cooling naturally to room temperature to obtain a yellow solid; (4) washing the yellow solid with deionized water three times and centrifuging, dispersing the yellow solid in DMF and stirring the suspension in the dark at room temperature for 24 hours, followed by centrifugation to remove the DMF, dispersing the solid in methanol and stirring in the dark at room temperature for 24 hours, followed by centrifugation to remove the methanol; and (5) The product after washing in step (4) is vacuum dried at 50° C. for 24 hours to obtain NH2-MIL-53(Al) powder.

[0007] The above NH2-MIL-53(Al) is applied to the detection of aflatoxins.

[0008] The method for detecting aflatoxin includes the steps of preparing a dispersion of the above-mentioned NH2-MIL-53(Al), adding a sample solution to be detected to the dispersion, incubating the mixture at room temperature, recording the fluorescence intensity of the mixed solution at 430 nm under excitation at 330 nm, and calculating the aflatoxin content in the sample to be detected by comparing the fluorescence intensity with a standard curve of aflatoxin concentration.

[0009] The above NH2-MIL-53(Al) is applied to the preparation of a reagent for detecting aflatoxin.

[0010] The electrospun nanofiber membrane loaded with NH2-MIL-53(Al) is prepared by electrospinning the above NH2-MIL-53(Al) into a nanofiber membrane.

[0011] In a specific embodiment, the method for preparing the electrospun nanofiber membrane loaded with NH2-MIL-53(Al) includes the steps of: The steps include taking the above NH2-MIL-53(Al) powder and polyacrylonitrile (PAN) and dissolving them in DMF, and vigorously stirring at 90°C for 2 hours to obtain a NH2-MIL-53(Al) / PAN solution, and loading the NH2-MIL-53(Al) / PAN solution into a disposable needle tube and putting it into an electrostatic spinning apparatus for spinning.

[0012] The above electrospun nanofibrous membrane loaded with NH2-MIL-53(Al) is applied for the detection of aflatoxin, and can also be used for the detection of aflatoxin in grains or peanuts.

[0013] The method for detecting aflatoxin using the above-mentioned electrospun nanofiber membrane loaded with NH2-MIL-53(Al) includes the steps of dropping a sample solution to be detected onto the electrospun nanofiber membrane loaded with NH2-MIL-53(Al), incubating at room temperature, taking a fluorescent photograph of the nanofiber, quickly acquiring the G and B data of the photograph using color recognition software, calculating the G / B value, substituting it into the relationship curve between G / B and aflatoxin concentration, and calculating the aflatoxin concentration in the material.

[0014] In a specific embodiment, the sample solution to be detected is obtained by taking a ground sample, mixing it with acetonitrile, evaporating the supernatant until it is almost dry, dispersing it in a PBS solution, centrifuging it, and filtering it through a 0.22 μm filter membrane to prepare the sample solution to be detected.

[0015] Advantages of the technical solution of the present invention This study provides a fluorescent detection platform based on low-concentration aluminum metal-organic framework for detecting AFB1. Specifically, NH2-MIL-53(Al) is used as the fluorescent platform. NH2-MIL-53(Al) has respiration and stability in aqueous solution. The amino group can interact with AFB1 through various intermolecular interactions, such as hydrogen bonding, acid-base effect, and coordination bond. The sensitivity and selectivity of NH2-MIL-53(Al) to AFB1 provide a new method for rapid detection of AFB1 in food. In addition, a portable flexible sensor is prepared by loading a fluorescent probe onto an electrospun nanofiber thin film. The successful combination of the flexible sensor with a smartphone significantly reduces the detection cost and time, providing a promising method for the qualitative recognition and quantitative detection of AFB1 in the field. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 shows the detection principle of aflatoxin B1 based on NH2-MIL-53(A1). [Diagram 2] FIG. 1 shows the stability of NH2-MIL-53(A1) solution. [Diagram 3] FIG. 1 shows the emission spectrum of NH2-MIL-53(A1). [Figure 4] FIG. 1 shows the excitation, emission and ultraviolet absorption spectra of NH2-MIL-53(A1). [Diagram 5] FIG. 1 shows the XRD pattern of NH2-MIL-53(A1). [Figure 6] FIG. 1 shows the Fourier transform infrared spectra of NH2-MIL-53(A1) and NH2-BDC. [Figure 7] FIG. 1 shows the thermogravimetric analysis (TGA) of NH2-MIL-53(A1). [Figure 8] FIG. 1 shows ultraviolet absorption spectra of NH2-MIL-53(A1) and NH2-MIL-53(A1)+AFB1. [Figure 9]FIG. 1 shows sensitivity diagrams and color change diagrams obtained by fluorescent detection of AFB1. [Figure 10] FIG. 1 shows the linear relationship of AFB1 concentration. [Figure 11] FIG. 1 shows a linear curve of the relationship between G / B and AFB1 concentration. [Figure 12] FIG. 1 shows electrospun nanofibers for AFB1 detection. [Figure 13] FIG. 1 shows the specificity of NH2-MIL-53(A1). [Figure 14] FIG. 13 is a diagram showing the anti-interference properties of NH2-MIL-53(A1). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Terms used in the present invention generally have the meanings commonly understood by those skilled in the art, unless otherwise specified.

[0018] The present invention will be described in more detail below with reference to data in combination with specific embodiments. The following embodiments are for illustrating the present invention, and are not intended to limit the scope of the present invention in any manner.

[0019] The principle of aflatoxin B1 detection according to the present invention is shown in Figure 1. NH2-MIL-53(Al) is prepared in a urea solution using AlCl3·6H2O and NH2-BDC, and the prepared NH2-MIL-53(Al) emits the strongest fluorescence at 430 nm with an excitation wavelength of 330 nm. The prepared NH2-MIL-53(Al) is directly dispersed in a PBS solution to prepare a dispersion, and the sample to be detected is added to the dispersion. If the sample to be detected contains AFB1, the fluorescence intensity at 430 nm is detected, and the AFB1 concentration in the sample to be detected is obtained by comparing the fluorescence intensity with the standard curve of AFB1 concentration.

[0020] Alternatively, the prepared NH2-MIL-53(Al) is prepared into an electrospun nanofiber membrane carrying NH2-MIL-53(Al) by electrospinning, the sample solution to be detected is dropped onto the nanofiber membrane, and the fluorescent photo of the nanofiber is taken with a smartphone. The photos of different colors can be converted into three values ​​of RGB through the color recognition APP, and the ratio of the G value and the B value can be taken to create a diagram. The G and B data of these photos can be quickly obtained through the color recognition APP, and the G / B value is calculated, which is then substituted into the linear curve of the relationship between G / B and AFB1 concentration to calculate and obtain the AFB1 concentration in this material.

[0021] Example 1 NH2-MIL-53(Al) is prepared by the following steps: Dissolve 1.448 g of AlCl3·6H2O in 30 mL of ultrapure water, add 1.088 g of NH2-BDC under magnetic stirring, and stir for 30 min to obtain "Solution 1". In a separate container, dissolve 0.576 g of urea in 10 mL of ultrapure water to obtain "Solution 2". Slowly add "Solution 2" to "Solution 1" with continuous stirring at room temperature for 30 min. Transfer the mixture to a polytetrafluoroethylene (PTFE)-lined reaction kettle and maintain it at 150 °C for 5 h. Then, allow it to cool naturally to room temperature. Wash the yellow solid three times with deionized water and separate it by centrifugation (12000 rpm, 10 min). Disperse the yellow solid in 40 mL of DMF and stir the suspension in the dark at room temperature for 24 h. Then, remove the DMF by centrifugation. Disperse the above solid in 40 mL of methanol and stir in the dark at room temperature for 24 h. Then, remove the methanol by centrifugation. Finally, the product is dried under vacuum at 50 °C for 24 h to obtain NH2-MIL-53(Al) powder.

[0022] Measurement of the emission spectrum of NH2-MIL-53(A1): The emission spectrum of NH2-MIL-53(A1) was recorded under excitation of 300-360 nm, and the fluorescence spectrum of 0.55μg / mL NH2-MIL-53(A1) solution was recorded respectively. The results are shown in Figure 2. When the excitation wavelength is 330 nm, the highest peak at 430 nm is observed, therefore, the optimal excitation wavelength of NH2-MIL-53(A1) is 330 nm.

[0023] The effects of different pH values, temperatures, UV irradiation and storage time on the stability of NH2-MIL-53(A1) solution were detected, and the specific measurement methods are as follows:

[0024] The pH:NH2-MIL-53(A1) solution was diluted with different pH solutions to 0.55 μg / mL, and the fluorescence intensity was tested under excitation at 330 nm using an enzyme marker, and the peak fluorescence intensity at 430 nm was recorded.

[0025] Temperature: 0.55 μg / mL NH2-MIL-53(A1) solution was placed at different temperatures and the fluorescence intensity was tested under excitation at 330 nm using an enzyme marker, and the fluorescence intensity at the peak 430 nm was recorded.

[0026] Ultraviolet irradiation: A 0.55 μg / mL NH2-MIL-53(A1) solution was irradiated with an ultraviolet lamp, and the fluorescence intensity was tested under excitation at 330 nm using an enzyme marker, and the fluorescence intensity at the peak of 430 nm was recorded.

[0027] Long-term storage: 0.55 μg / mL NH2-MIL-53(A1) solution was placed at room temperature, and the fluorescence stability was tested after 1, 3, 5, 7, 15, and 30 days, and the fluorescence intensity was tested under excitation at 330 nm using an enzyme marker.

[0028] The stability of the NH2-MIL-53(A1) solution is shown in Figure 3. The fluorescence intensity of the NH2-MIL-53(A1) solution was examined under different pH, temperature, UV irradiation and long-term storage conditions, and it was found that the fluorescence intensity of the NH2-MIL-53(A1) solution was relatively stable. This indicates that the NH2-MIL-53(A1) solution has excellent optical properties and can be better used for the subsequent detection of AFB1.

[0029] The excitation, emission and ultraviolet absorption spectra of NH2-MIL-53(A1) are measured by the following steps.

[0030] Excitation spectrum: 0.55 μg / mL of NH2-MIL-53(A1) solution was added to a 96-well black enzyme marker plate and the excitation spectrum was recorded with emission at 430 nm.

[0031] Emission spectrum: 0.55 μg / mL of NH2-MIL-53(A1) solution was added to a 96-well black enzyme marker plate, and the emission spectrum was recorded under excitation at 330 nm.

[0032] Ultraviolet absorption spectrum: 2 mL of the NH2-MIL-53(A1) solution was taken and added to a quartz cuvette, which was then placed in an ultraviolet spectrophotometer, and the ultraviolet absorption spectrum was recorded in the wavelength range of 200-600 nm.

[0033] The optical properties of NH2-MIL-53(A1) were evaluated, and the results are shown in Figure 4. The ultraviolet absorption spectrum exhibited two characteristic absorption peaks at 220 nm and 330 nm. The absorption peak at 220 nm was due to the π-π* jump of C=C group or the n-π* jump of C=O group. The characteristic absorption peak at 330 nm was due to the n-π* jump of C=O / CN group, which coincided with the optimal excitation wavelength of the fluorescence spectrum.

[0034] Method for measuring the XRD pattern of NH2-MIL-53(A1): Use an X-ray diffractometer to measure the XRD pattern of NH2-MIL-53(A1) powder. The NH2-MIL-53(A1) powder was polished, and an appropriate amount of powder was taken and placed on a grooved glass plate, which was then placed on the device for testing. The results are shown in Figure 5, which shows that the crystallization of the precursor of the prepared NH2-MIL-53(A1) nanosheets was good. The typical peaks were at 8.8°, 10.4°, 15.0°, 17.5°, 20.0° and 26.4°, which also proved that the material was successfully prepared.

[0035] Method for detecting NH2-MIL-53(A1) and NH2-BDC by Fourier transform infrared spectrum: A Fourier transform infrared spectrometer is used to measure the infrared spectrum of NH2-MIL-53(A1) powder and NH2-BDC powder. An appropriate amount of powder of the above two substances is placed in the instrument, and the infrared spectrum is recorded after removing the background interference of air. The result is shown in Figure 6, where the infrared spectrum of 3504 cm -1 and 3390cm -1 The band at 1000-1100 cm corresponds to the asymmetric stretching vibration of the NH bond, which indicates that the NH-MIL-53(Al) nanosheet contains many hydroxyl groups, which is significantly advantageous for water solubility. -1 The new spectral bands in NH2-BDC come from the stretching vibration of the Al-O bond, which indicates that the O atom in NH2-BDC is Al 3+ It further shows that the metal-organic framework is formed by coordinating with

[0036] Method for detecting thermogravimetric analysis (TGA) of NH2-MIL-53(A1): A differential scanning calorimeter was used to test the thermogravimetric analysis (TGA) of NH2-MIL-53(A1). A maximum of 0.5g of NH2-MIL-53(A1) powder was taken and placed in a small crucible, then placed in the apparatus, and the temperature range was set to 30-800°C to test its thermal stability. The results are shown in Figure 7. When the thermal stability of NH2-MIL-53(A1) was examined, the TGA data revealed that it was thermally stable up to 280°C.

[0037] Example 2 Electrospun nanofibrous membranes loaded with NH2-MIL-53(Al) were prepared by the following steps.

[0038] 10 mg of the NH2-MIL-53(Al) powder prepared by the method of Example 1 and 1 g of polyacrylonitrile (PAN) (Mw=150,000) are dissolved in 9 mL of DMF and vigorously stirred at 90° C. for 2 hours to obtain a NH2-MIL-53(Al) / PAN solution.

[0039] The above NH2-MIL-53(Al) / PAN solution is loaded into a 10 mL disposable needle tube and placed in an electrostatic spinning apparatus for spinning. The NH2-MIL-53(Al) nanofiber membrane is prepared using a YFSP-T electrostatic spinning apparatus, and a syringe pump is used to spin the solution at 0.002 mms under the conditions that the high voltage is 30 Kv and the receiver rotation speed is 0.1 rpm / min. -1 Insert it into the needle at a speed of .

[0040] Example 3 Application of NH2-MIL-53(Al) in the detection of aflatoxin B1 5 mg of NH2-MIL-53(A1) prepared in Example 1 was dispersed in 10 mL of PBS (0.01 M, pH=7.4) at room temperature and sonicated for 5 minutes. After dilution, 0.55 μg / mL NH2-MIL-53(A1) dispersion was prepared, and the sample to be detected was added to the NH2-MIL-53(A1) dispersion, incubated at room temperature for 5 minutes, and then the fluorescence intensity of the mixed solution at 430 nm under excitation at 330 nm was recorded. The content of aflatoxin B1 in the sample to be detected was calculated by matching the fluorescence intensity with the standard curve of AFB1 concentration.

[0041] Method for detecting the ultraviolet absorption spectrum of NH2-MIL-53(A1) and NH2-MIL-53(A1)+AFB1: 2mL of NH2-MIL-53(A1) solution and NH2-MIL-53(A1)+AFB1 mixture were respectively taken, added to a quartz cuvette, and placed in an ultraviolet spectrophotometer to record the ultraviolet absorption spectrum in the wavelength range of 200-600nm. The results are shown in Figure 8. l Upon addition of AFB, the absorption peak of NH2-MIL-53(Al) at 330 nm was red-shifted to 340 nm, which indicates that the absorption peak of NH2-MIL-53(Al) and AFB l It was further confirmed that there exists a strong interaction between

[0042] The steps of fluorescence detection of the sensitivity diagram and color change of AFB1 are as follows. Different concentrations of AFB1 solutions were added to 0.55μg / mL NH2-MIL-53(Al) solution, mixed uniformly, and then incubated at room temperature for 5 minutes. Each solution was added to a 96-well black enzyme marker plate, and its fluorescence was recorded under excitation at 330nm. The results are shown in Figure 9, which shows that with increasing AFB1 concentration, the blue fluorescence of NH2-MIL-53(Al) is excited, and the blue light is stronger, that is, the peak at 430nm continues to increase. As shown in Figure 10, the linear relationship of AFB1 concentration is that when the added amount of AFB1 is 0, the peak at 430nm is taken as the base, that is, F0, and the peaks at other concentrations are taken as F. Calculating F / F0, this ratio has a linear relationship with AFB1, and the R of the linear relationship is 2 = 0.99 proves that the linear relationship is good and the data is meaningful, with a linear range of 0-40 μM and a detection limit of 3.1 ppb.

[0043] Example 4 Application of NH2-MIL-53(Al) nanofibrous membrane in detection of aflatoxin B1 NH2-MIL-53(Al) nanofibers were cut into disks with a diameter of 1 cm. 15 μL of AFB1 solutions with different concentrations were dropped onto them. After 5 minutes, fluorescent photos of the nanofibers were taken with a smartphone under irradiation with a 365 nm ultraviolet lamp. The G and B data of these photos were quickly obtained with a color recognition APP, and the G / B value was calculated and substituted into the linear curve of the relationship between G / B and AFB1 concentration (as shown in Figure 11, the linear range is 0-30 μM, and the detection limit is 29.2 ppb), and the AFB1 concentration in this material was calculated and obtained.

[0044] The detection result of AFB1 using NH2-MIL-53(Al) nanofiber was observed by observing the color change under irradiation of a 365 nm ultraviolet lamp, as shown in Figure 12. It was clearly observed with the naked eye that the blue fluorescence became stronger as the concentration of AFB1 increased.

[0045] Example 5 Specificity of NH2-MIL-53(Al) 5 mg of NH2-MIL-53(A1) prepared in Example 1 was dispersed in 10 mL of PBS (0.01 M, pH=7.4) and sonicated for 5 minutes. After dilution, a 0.55 μg / mL NH2-MIL-53(A1) dispersion was prepared and used in the fluorescence experiment. Then, 50 μL of 100 μM AFB1 solution was added to 900 μL of the dispersion to make the final concentration of AFB1 5 μM, or interfering substances were added to 900 μL of the dispersion to make the concentrations of ochratoxin (OTA) and zearalenone (ZEN) 5 μM and the concentrations of other interfering substances 200 μM. The interfering substances were ochratoxin (OTA), zearalenone (ZEN) Na, and zearalenone (ZEN) Na. + , K + , Ca 2+ , Zn 2+ , Mg 2+ , Mn 2+ , Hg 2+ , Co 2+ , Fe 3+ , Al 3+ , B.A. 2+, ascorbic acid (AA), gallic acid (GA), aspartic acid (Asp), tryptophan (Try), L-lysine (Lys), L-cysteine ​​(Cys), L-glutamic acid (Glu), glucose (GL), sucrose (SR), lactose (LC), fructose (FR) and ML (maltose). After 5 min of incubation at room temperature, the fluorescence intensity at the emission peak of the mixed solution at 430 nm was recorded under excitation at 330 nm, and the F / F0 was calculated to create a figure. F0 means the fluorescence intensity at 430 nm without the addition of AFB1, and F means the fluorescence intensity at 430 nm after the addition of AFB1 or other substances. All tests were repeated three times to ensure statistical accuracy.

[0046] As shown in FIG. 13, the results show that NH2-MIL-53(Al) is highly reactive to aflatoxin B1, ochratoxin (OTA), and zearalenone (ZEN), and is most sensitive to AFB1 among them.

[0047] Anti-interference properties of NH2-MIL-53(Al) 5 mg of NH2-MIL-53(A1) prepared in Example 1 was dispersed in 10 mL of PBS (0.01 M, pH=7.4) at room temperature and sonicated for 5 minutes. After dilution, a 0.55 μg / mL NH2-MIL-53(A1) dispersion was prepared and used in the fluorescence experiment. Then, 100 μM AFB1 solution was added to the dispersion so that the final concentration of AFB1 was 5 μM. Then, the interfering substances ochratoxin (OTA), zearalenone (ZEN), Na were added to the solution containing AFB1. + , K + , Ca 2+ , Zn 2+ , Mg 2+ , Mn 2+ , Hg 2+ , Co 2+ , Fe 3+ , Al 3+ , B.A. 2+, ascorbic acid (AA), gallic acid (GA), aspartic acid (Asp), tryptophan (Try), L-lysine (Lys), L-cysteine ​​(Cys), L-glutamic acid (Glu), glucose (GL), sucrose (SR), lactose (LC), fructose (FR), and ML (maltose) were added to investigate the anti-interference properties of NH2-MIL-53(Al) when AFB1 and interferences exist simultaneously. Here, the concentration of AFB1 is 5 μM, the concentrations of OTA and ZEN are also 5 μM, and the concentrations of other interferences are 250 μM. After incubation at room temperature for 5 minutes, the fluorescence intensity at the emission peak 430 nm of the mixed solution was recorded under excitation at 330 nm, and the value of F / F0 was calculated and a figure was prepared. F0 means the fluorescence intensity at 430 nm when AFB1 is not added, and F means the fluorescence intensity at 430 nm after adding AFB1 or other substances. All tests were repeated three times to ensure statistical accuracy.

[0048] The results are shown in Fig. 14, which shows that when AFB1 and an interferent are simultaneously present, NH2-MIL-53(Al) has good anti-interference properties.

[0049] Example 6 Application and stability of NH2-MIL-53(Al) in detecting AFB1 in real samples Pretreatment of samples awaiting detection: Ground rice samples (200 g) were taken and mixed with 400 mL of acetonitrile for 20 min, then the supernatant was rotary evaporated to near dryness, and then dispersed in 100 mL of PBS solution. The mixture was centrifuged (10,000 rpm, 10 min) and filtered through a 0.22 μm filter membrane to obtain the sample solution awaiting detection.

[0050] The sample solution to be detected is added to the dispersion of NH2-MIL-53(A1) and incubated at room temperature for 5 minutes. The fluorescence spectrum of the mixed solution at 430 nm is recorded under excitation at 330 nm, and the content of aflatoxin B1 in the sample to be detected is calculated by comparing the fluorescence intensity with the standard curve of AFB1 concentration.

[0051] Alternatively, the sample solution to be detected was dropped onto a NH2-MIL-53(Al) nanofiber membrane cut into a disk shape with a diameter of 1 cm, and after 5 minutes, the fluorescent photos of the nanofibers were taken with a smartphone. The G and B data of these photos were quickly obtained through a color recognition APP, and the G / B value was calculated, which was then substituted into the linear curve of the relationship between G / B and AFB1 concentration to calculate the AFB1 concentration in this material.

[0052] Stability of the detection method Rice samples were treated as described above, and the final concentrations of the blank rice sample solution were 0.1, 0.5, 1, 2.5, and 5 μmol L -1 The above mixture was added to the NH2-MIL-53(A1) dispersion and incubated at room temperature for 5 minutes. The fluorescence spectrum of the mixture was recorded at 430 nm under excitation at 330 nm, and the content of aflatoxin B1 in the sample to be detected was calculated by comparing the fluorescence intensity with the standard curve of AFB1 concentration. The recovery rate of AFB1 was calculated, and the results are shown in Table 1.

[0053] JPEG2024180218000001.jpg67150

[0054] As can be seen from Table 1, the method of the present invention is stable and can be used to detect AFB1 in actual samples.

[0055] The above description is merely a more preferred embodiment of the present invention, and does not limit the present invention to other forms, and a person skilled in the art can use the above disclosed technical content to change or modify the above embodiment into an equivalent embodiment with equivalent changes. However, if the above embodiment is simply modified, equivalently modified, and modified based on the technical substance of the present invention without departing from the content of the technical solution of the present invention, it still falls within the protection scope of the technical solution of the present invention.

Claims

1. N.H. ２ MIL-53(Al), Said NH ２ -The method for preparing MIL-53(Al) was as follows: (1) AlCl ３ ・6H ２ Dissolve O in ultrapure water and add NH ２ - adding BDC and stirring to obtain "solution 1"; (2) dissolving urea in ultrapure water to obtain "solution 2"; (3) slowly adding "Solution 2" to "Solution 1" with continuous stirring, stirring uniformly, and maintaining at 150°C for 5 hours, and then naturally cooling to room temperature to obtain a yellow solid; (4) washing the yellow solid with deionized water three times and centrifuging, dispersing the yellow solid in DMF and stirring the suspension in the dark at room temperature for 24 hours, followed by centrifugation to remove the DMF, dispersing the solid in methanol and stirring in the dark at room temperature for 24 hours, followed by centrifugation to remove the methanol; and (5) The product after washing in step (4) was dried in vacuum at 50° C. for 24 hours to obtain NH ２ NH2-MIL-53(Al) powder is obtained.

2. NH2-MIL-53(Al) according to claim 1 is used for detecting aflatoxin.

3. A method for detecting aflatoxin, comprising: NH according to claim 1 ２ aflatoxin detection method comprising the steps of preparing a dispersion of -MIL-53(Al), adding a sample solution to be detected to the dispersion, incubating the mixture at room temperature, recording the fluorescence intensity at 430 nm of the mixed solution under excitation at 330 nm, and calculating the aflatoxin content in the sample to be detected by comparing the fluorescence intensity with a standard curve of aflatoxin concentration.

4. NH according to claim 1 ２ - Application of MIL-53(Al) to the preparation of a reagent for detecting aflatoxin.

5. N.H. ２ - an electrospun nanofiber membrane supported on MIL-53(Al), The NH2-MIL-53(Al) of claim 1 is prepared into a nanofiber membrane by electrospinning. ２ - Electrospun nanofiber membrane loaded with MIL-53(Al).

6. N.H. ２ The preparation method of electrospun nanofiber membrane loaded with MIL-53(Al) is as follows: NH according to claim 1 ２ -MIL-53 (Al) powder and polyacrylonitrile (PAN) were taken and dissolved in DMF, and vigorously stirred at 90°C for 2 hours to obtain NH ２ obtaining a MIL-53(Al) / PAN solution; ２ - loading the MIL-53(Al) / PAN solution into a disposable needle tube and then placing it into an electrospinning device for spinning. ２ - Electrospun nanofiber membrane loaded with MIL-53(Al).

7. NH according to claim 6 ２ - Application characterized by the application of electrospun nanofibrous membrane loaded with MIL-53(Al) for the detection of aflatoxins.

8. 8. Application according to claim 7, characterized in that it is used for the detection of aflatoxins in cereals or peanuts.

9. NH according to claim 6 ２ A method for detecting aflatoxins using an electrospun nanofiber membrane loaded with MIL-53(Al), comprising: N.H. ２ A sample solution to be detected is dropped onto an electrospun nanofiber membrane carrying -MIL-53(Al), and after incubation at room temperature, a fluorescent photograph of the nanofiber is taken, and the G and B data of the photograph are rapidly obtained by a color recognition software, and the G / B value is calculated, and the calculated value is substituted into a relationship curve between G / B and aflatoxin concentration, thereby obtaining the aflatoxin concentration in the material. ２ - A method for detecting aflatoxins using electrospun nanofibrous membranes loaded with MIL-53(Al).

10. NH according to claim 6 ２ A method for detecting aflatoxins using an electrospun nanofiber membrane loaded with MIL-53(Al), The sample solution to be detected is obtained by taking a crushed sample, mixing it with acetonitrile, evaporating the supernatant until it is almost dry, dispersing it in a PBS solution, centrifuging it, and filtering it through a 0.22 μm filter membrane to prepare a sample solution to be detected, according to claim 9. ２ - A method for detecting aflatoxins using electrospun nanofibrous membranes loaded with MIL-53(Al).

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