A kind of aggregation-induced emission-metal-organic framework probe and the method for detecting chlorpyrifos

Abstract

This invention discloses an aggregation-induced emission (AIE)-metal-organic framework probe, which is prepared by a one-pot solvothermal method using manganese chloride tetrahydrate as the metal center and 1,1,2,2-tetra(4-carboxyphenyl)ethylene as the organic ligand. This invention also discloses a method for detecting chlorpyrifos using a fluorescence sensing system constructed based on the aforementioned AIE-metal-organic framework probe. The AIE-metal-organic framework probe of this invention exhibits low fluorescence background, which reduces background signal interference during chlorpyrifos detection and improves sensitivity. Furthermore, the introduction of enzyme-mediated controllable recognition elements enables specific and sensitive detection of chlorpyrifos, with a detection limit of 3.79 ng / mL. ‑1 The aggregation-induced emission-metal-organic framework probe of this invention exhibits advantages such as high sensitivity, high selectivity, rapid response, stability, and ease of operation in the detection of chlorpyrifos, and has broad application prospects.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of analytical detection, and relates to an aggregation-induced emission-metal-organic framework (AIE-MOF) probe, a method for detecting ascorate oxidase based on a fluorescence sensing system constructed by the aggregation-induced emission-metal-organic framework probe, and a method for detecting chlorpyrifos based on a fluorescence sensing system constructed by the aggregation-induced emission-metal-organic framework probe. BACKGROUND

[0002] Organophosphorus pesticides (OP) are essential for the control of agricultural pests, improving productivity and economic benefits. Chlorpyrifos is a highly effective and broad-spectrum organophosphorus insecticide that plays an important role in agriculture. However, due to the widespread use and long-term overuse of chlorpyrifos, it has also led to serious environmental pollution and various health problems. Therefore, if a simple and sensitive method for detecting chlorpyrifos can be established, it can play a crucial role in protecting the ecological environment and human health. Traditional chromatographic detection methods can effectively detect chlorpyrifos, but the detection equipment used is expensive and the detection process is time-consuming, and it also requires well-trained personnel and professional operation. Therefore, people are still striving to develop simpler, more cost-effective and more reliable alternative methods to detect chlorpyrifos. Fluorescence technology is praised for its sensitivity, convenience and cost-effectiveness, and has been widely adopted and become an effective method for detecting pesticides.

[0003] Metal-organic frameworks (MOFs) are a class of porous crystalline materials, which are suitable for catalysis, gas storage, photocatalytic degradation and sensing analysis due to their high specific surface area, adjustable porosity and structural stability. The characteristic of aggregation-induced emission (AIE) is that organic molecules exhibit weak or negligible fluorescence in solution, but exhibit strong fluorescence emission upon aggregation. This characteristic makes AIE materials have the advantages of high signal-to-noise ratio and low background interference in fluorescence detection. By combining AIE molecules with MOFs, the high specific surface area, physical and chemical stability, adjustable pore size and metal active sites of MOFs can be utilized to construct a highly efficient fluorescence sensor.

[0004] However, the existing AIE-MOF technology has a relatively single signal output mode, usually adopting a "from on to off" signal output mode, which has a high background signal and limits the further improvement of sensitivity. SUMMARY

[0005] The application aims to provide an aggregation-induced emission-metal-organic framework (AIE-MOF) probe and construct a fluorescence sensing system based on the AIE-MOF probe, which can be used for targeted and controllable fluorescence detection of chlorpyrifos.

[0006] The application aims to achieve the above-mentioned purposes by the following technical solutions.

[0007] The application aims to achieve the above-mentioned purposes by the following technical solutions.

[0008] Preferably, the aggregation-induced emission-metal-organic framework probe is prepared by dissolving manganese chloride tetrahydrate and 1,1,2,2-tetrakis(4-carboxyphenyl)ethylene in N,N-dimethylacetamide, adding an appropriate amount of acetic acid to adjust the pore size, mixing, and reacting at a temperature of 100-120 DEG C for 12-16 hours; after the reaction is completed, centrifugation is performed, the supernatant is discarded, the precipitate is washed with acetonitrile, and the aggregation-induced emission-metal-organic framework probe is obtained.

[0009] The application aims to achieve the above-mentioned purposes by the following technical solutions.

[0010] The molar ratio of the manganese chloride tetrahydrate and 1,1,2,2-tetrakis(4-carboxyphenyl)ethylene is 5:1-5.15:1.

[0011] The amount ratio of the acetic acid and 1,1,2,2-tetrakis(4-carboxyphenyl)ethylene is 1:20-1:30 mL / mg.

[0012] The mass-volume ratio of the 1,1,2,2-tetrakis(4-carboxyphenyl)ethylene and N,N-dimethylacetamide is 10:1-5:1 mg / mL.

[0013] The application aims to achieve the above-mentioned purposes by the following technical solutions.

[0014] Step (1), dispersing the AIE-MOF probe in acetonitrile, diluting with ultrapure water to obtain an AIE-MOF probe dispersion, or dispersing the AIE-MOF probe in ultrapure water to obtain an AIE-MOF probe dispersion;

[0015] Step (2), constructing a fluorescence sensing system: adding an ascorbic acid oxidase aqueous solution with different enzyme activities and an ascorbic acid aqueous solution, ultrapure water in a phosphate buffered saline solution (PBS), incubating at a temperature of 35-40℃ for 30-50 minutes, adding the AIE-MOF probe dispersion to the reaction system, and reacting at a temperature of 35-40℃ for 15-30 minutes to obtain a detection system; using a multi-label detection system, taking 348 nm as the excitation wavelength, measuring the fluorescence intensity of the detection system at 427 nm, taking the enzyme activity or log value of the ascorbic acid oxidase as the abscissa, and taking the fluorescence intensity at 427 nm as the ordinate to establish an ascorbic acid oxidase standard curve;

[0016] Step (3), sample detection: according to step (2), the fluorescence intensity of the unknown ascorbic acid oxidase sample to be tested at an excitation wavelength of 348 nm is measured at 427 nm, and the fluorescence intensity is substituted into the ascorbic acid oxidase standard curve of step (2) to obtain the concentration of ascorbic acid oxidase in the sample to be tested.

[0017] In step (1), preferably, the AIE-MOF probe is dispersed in acetonitrile, diluted 4 times with ultrapure water to obtain an AIE-MOF probe dispersion.

[0018] In step (2), the pH of the phosphate buffered saline solution is 6.5-7.4, preferably pH 7.

[0019] In the detection system, the final concentration of ascorbic acid is 0.5-1.5 mM, preferably 1 mM; the final concentration of AIE-MOF probe is 50-100 mg·L -1 , preferably 62.5 mg·L -1 ; the final concentration of ascorbic acid oxidase is 0.001-0.8 U·mL -1 . Ascorbic acid oxidase has good linearity in the range of 0.001-0.8 U mL -1 .

[0020] Preferably, the volume ratio of the phosphate buffered saline solution, the ascorbic acid oxidase aqueous solution, the ascorbic acid aqueous solution, the ultrapure water and the AIE-MOF probe dispersion is 1:1:1:6:1.

[0021] Preferably, the fluorescence sensing system is constructed by adding the ascorate oxidase aqueous solution with different enzyme activities, the ascorbic acid aqueous solution, ultrapure water into the phosphate buffered saline solution, incubating at 37℃ for 40 minutes, adding the AIE-MOF probe dispersion into the reaction system, and reacting at 37℃ for 20 minutes to obtain the detection system.

[0022] In step (3), the sample detection is performed by adding the sample to be detected, the ascorbic acid aqueous solution and ultrapure water into the phosphate buffered saline solution, incubating at 35-40℃ for 30-50 minutes, adding the AIE-MOF probe dispersion into the reaction system, and reacting at 35-40℃ for 15-30 minutes to obtain the detection system.

[0023] Preferably, the sample detection is performed by adding the sample to be detected, the ascorbic acid aqueous solution and ultrapure water into the phosphate buffered saline solution, incubating at 37℃ for 40 minutes, adding the AIE-MOF probe dispersion into the reaction system, and reacting at 37℃ for 20 minutes to obtain the detection system.

[0024] The volume ratio of the phosphate buffered saline solution, the sample to be detected, the ascorbic acid aqueous solution, ultrapure water and the AIE-MOF probe dispersion is 1:1:1:6:1.

[0025] The pH of the phosphate buffered saline solution is 6.5-7.4, preferably 7.

[0026] In the detection system, the final concentration of ascorbic acid is 0.5-1.5mM, preferably 1mM; and the final concentration of the AIE-MOF probe is 50-100mg·L -1 , preferably 62.5mg·L -1 .

[0027] Another object of the present application is to provide a method for detecting chlorpyrifos based on the fluorescence sensing system constructed by the AIE-MOF probe, which comprises the following steps:

[0028] Step (1), dispersing the AIE-MOF probe in acetonitrile and diluting with ultrapure water to obtain an AIE-MOF probe dispersion, or dispersing the AIE-MOF probe in ultrapure water to obtain an AIE-MOF probe dispersion;

[0029] Step (2), constructing the fluorescence sensing system: adding different concentrations of chlorpyrifos methanol or aqueous solution and ascorbic acid oxidase aqueous solution in phosphate buffered saline (PBS) solution, incubating at a temperature of 35-40℃ for 50-80 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at a temperature of 35-40℃ for 15-40 minutes, finally adding AIE-MOF probe dispersion to the reaction system, reacting at a temperature of 35-40℃ for 15-30 minutes to obtain the detection system, using a multi-label detection system, taking 348 nm as the excitation wavelength, measuring the fluorescence intensity of the detection system at 427 nm, taking the concentration or log value of chlorpyrifos as the abscissa and the fluorescence intensity at 427 nm as the ordinate, and establishing a chlorpyrifos standard curve;

[0030] Step (3), sample detection; according to step (2), the fluorescence intensity of the unknown chlorpyrifos concentration sample to be detected at an excitation wavelength of 348 nm is measured, the fluorescence intensity is substituted into the chlorpyrifos standard curve of step (2), and the concentration of chlorpyrifos in the sample to be detected is obtained.

[0031] In step (1), preferably, the AIE-MOF probe is dispersed in acetonitrile, diluted 4 times with ultrapure water, and an AIE-MOF probe dispersion is obtained.

[0032] In step (2), the pH of the phosphate buffered saline solution is 6.5-7.4, preferably pH 7.

[0033] In the detection system, the enzyme activity of ascorbic acid oxidase is 0.1-0.8 U·mL -1 , preferably 0.2 U·mL -1 ; the final concentration of ascorbic acid is 0.5-1.5 mM, preferably 1 mM; the final concentration of AIE-MOF probe is 50-100 mg·L -1 , preferably 62.5 mg·L -1 ; the final concentration of chlorpyrifos is 0.005-5 mg·L -1 , and chlorpyrifos has good linearity in the range of 0.005-5 mg·L -1 .

[0034] Preferably, the volume ratio of the phosphate buffered saline solution, the chlorpyrifos methanol solution, the ascorbic acid oxidase aqueous solution, the ascorbic acid aqueous solution, the ultrapure water and the AIE-MOF probe dispersion is 1:1:1:1:5:1.

[0035] Preferably, the fluorescence sensing system is constructed by adding chlorpyrifos methanol solution and ascorbic acid oxidase aqueous solution with different concentrations in phosphate buffered saline solution, incubating at 35-40℃ for 60-80 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at 35-40℃ for 15-40 minutes, and finally adding AIE-MOF probe dispersion to the reaction system, reacting at 35-40℃ for 15-40 minutes to obtain the detection system.

[0036] More preferably, the fluorescence sensing system is constructed by adding chlorpyrifos methanol solution and ascorbic acid oxidase aqueous solution with different concentrations in phosphate buffered saline solution, incubating at 37℃ for 60 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at 37℃ for 40 minutes, and finally adding AIE-MOF probe dispersion to the reaction system, reacting at 37℃ for 20 minutes to obtain the detection system.

[0037] In step (3), preferably, the sample is detected by adding the sample to be detected and ascorbic acid oxidase aqueous solution in phosphate buffered saline solution (PBS), incubating at 35-40℃ for 50-80 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at 35-40℃ for 15-40 minutes, and finally adding AIE-MOF probe dispersion to the reaction system, reacting at 35-40℃ for 15-30 minutes to obtain the detection system.

[0038] Preferably, the fluorescence sensing system is constructed by adding the sample to be detected and ascorbic acid oxidase aqueous solution in phosphate buffered saline solution, incubating at 35-40℃ for 60-80 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at 35-40℃ for 15-40 minutes, and finally adding AIE-MOF probe dispersion to the reaction system, reacting at 35-40℃ for 15-40 minutes to obtain the detection system.

[0039] More preferably, the fluorescence sensing system is constructed by adding the sample to be detected and ascorbic acid oxidase aqueous solution in phosphate buffered saline solution, incubating at 37℃ for 60 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at 37℃ for 40 minutes, and finally adding AIE-MOF probe dispersion to the reaction system, reacting at 37℃ for 20 minutes to obtain the detection system.

[0040] Preferably, the volume ratio of the phosphate buffered saline solution, the sample to be detected, the ascorbic acid oxidase aqueous solution, the ascorbic acid aqueous solution, the ultrapure water and the AIE-MOF probe dispersion is 1:1:1:1:5:1.

[0041] The sample to be detected is a sample obtained by pretreatment in the art, such as crops, food, water samples and soil that may be contaminated by chlorpyrifos.

[0042] The preparation process of the AIE-MOF probe is as shown in the following formula. Figure 1 The AIE-MOF probe is prepared by one-pot solvothermal method, taking manganese cluster (Mn cluster) as a metal node and a blocking agent, and taking non-aggregated 1,1,2,2-tetrakis (4-carboxyphenyl) ethylene as an organic ligand. The fluorescence of the AIE ligand in the AIE-MOF probe is quenched by Mn(III) through resonance energy transfer (FRET), providing a lower background fluorescence.

[0043] The working principle of the present application is as shown in the following formula. Figure 2 In an organic solvent (N,N-diethylacetamide), the fluorescence of the non-aggregated AIE molecule is quenched by Mn(III) through resonance energy transfer (FRET), resulting in a lower fluorescence background of the AIE-MOF (AIE-MOF). In the presence of ascorbic acid (AA), Mn(III) in the AIE-MOF is reduced to Mn(II), which promotes the dissociation of the AIE-MOF skeleton and releases the AIE molecules into water. The AIE molecules re-aggregate to form aggregates in the aqueous solution, significantly enhancing the fluorescence caused by the AIE (AIE-MOF / AA). When AA is oxidized by ascorbate oxidase (AAox) (AIE-MOF / AA / AAox), the fluorescence of the AIE molecules is restored and the aggregation emission is weakened due to the limitation of Mn(III) delocalization and AIE-MOF skeleton cracking. At the same time, chlorpyrifos hinders the consumption of AAox by inhibiting the catalytic activity of AAox, so that AA can continue to react with AIE-MOF to restore fluorescence (AIE-MOF / AA / AAox / chlorpyrifos). Therefore, the AIE-MOF / AA system converts the inhibitory effect of chlorpyrifos on AAox into a fluorescence signal, providing a sensitive and highly selective method for detecting chlorpyrifos.

[0044] Based on the excellent fluorescence emission advantage of the AIE molecule and the structure-adjustable characteristics of the MOF skeleton, the present application prepares an AIE-MOF probe with stable structure, which not only ensures the formation of a stable MOF structure, but also effectively improves the loading efficiency of the AIE molecule. At the same time, the enzyme-mediated as a controllable recognition element can sensitively detect chlorpyrifos in crops, showing advantages of high sensitivity, high selectivity, rapid response, stability and simple operation, etc., and has a wide application prospect. Compared with the existing detection methods of chlorpyrifos, the present application has the following advantages:

[0045] 1. This invention utilizes the fluorescence properties of the AIE-MOF probe to regulate the fluorescence signal through the interaction between Mn(III) and the AIE ligand; the fluorescence signal is significantly enhanced in the presence of chlorpyrifos, with a detection limit of 3.79 ng·mL. -1 It is below the maximum residue limit stipulated by China (0.2 mg·L⁻¹). -1 It can achieve highly sensitive detection of chlorpyrifos.

[0046] 2. The AIE-MOF probe of this invention passes through the initial state. The resonance energy transfer (FRET) mechanism achieves fluorescence quenching with extremely low background fluorescence, which reduces background signal interference when detecting chlorpyrifos and improves sensitivity. This feature effectively solves the problem of high background signal in existing fluorescence detection methods and significantly improves the signal-to-noise ratio.

[0047] 3. The AIE-MOF probe of this invention utilizes the specific inhibitory effect of chlorpyrifos on ascorbic acid oxidase (AAox) to convert the presence of chlorpyrifos into a fluorescent signal, thereby achieving specific detection of chlorpyrifos. Compared with traditional detection methods, this invention has higher selectivity and anti-interference ability.

[0048] 4. The manganese released by the AIE-MOF probe of this invention is beneficial to plant growth and can improve plant stress resistance and yield. Compared with existing detection methods, this invention not only reduces environmental pollution, but also has cost-effectiveness and environmental protection potential.

[0049] 5. The AIE-MOF probe preparation method of this invention is simple, requiring no complex instruments or cumbersome steps, and is suitable for large-scale production and field applications; compared with traditional fluorescence sensor preparation methods, the operation of this invention is simpler and the cost is lower. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the preparation of the AIE-MOF probe.

[0051] Figure 2 A schematic diagram of the application of AIE-MOF probe for detecting chlorpyrifos (A) and a schematic diagram of the working principle of AIE-MOF probe-based fluorescence sensing system for detecting chlorpyrifos (B).

[0052] Figure 3Figure is the characterization chart of AIE-MOF probe; wherein, A is the transmission electron microscope (TEM) image of AIE-MOF probe; B is the particle size distribution chart of AIE-MOF probe; C is the X-ray diffraction chart of AIE-MOF probe, AIE-MOF is the X-ray diffraction chart of AIE-MOF probe, Simulated AIE-MOF is the simulation data of AIE-MOF probe; D is the Fourier transform infrared (FT-IR) spectrum of AIE-MOF probe; E is the X-ray photoelectron spectroscopy (XPS) full spectrum chart of AIE-MOF probe; F is the X-ray photoelectron spectroscopy (XPS) fine spectrum chart of AIE-MOF probe.

[0053] Figure 4 Figure is the relationship chart of fluorescence intensity and ascorbic acid oxidase activity of AIE-MOF / AA system; wherein, A is the fluorescence spectrum chart of AIE-MOF / AA system and ascorbic acid oxidase activity (0, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5 and 0.8 U mL -1 ) under; B is the linear relationship chart between fluorescence intensity and ascorbic acid oxidase activity of AIE-MOF / AA system.

[0054] Figure 5 Figure is the relationship chart of fluorescence intensity and chlorpyrifos concentration of AIE-MOF / AA / AAox / chlorpyrifos system; wherein, A is the fluorescence spectrum chart of AIE-MOF / AA / AAox / chlorpyrifos system and chlorpyrifos concentration (0, 0.005, 0.01, 0.05, 0.1, 0.5, 1 and 5 mg L -1 ) under; B is the linear relationship chart between fluorescence intensity and chlorpyrifos concentration of AIE-MOF / AA / AAox / chlorpyrifos system.

[0055] Figure 6 Figure is the determination of chlorpyrifos accumulation in wheat by HPLC method and fluorescence sensing system; wherein, A is the accumulation of chlorpyrifos in the aboveground tissues of wheat; B is the accumulation of chlorpyrifos in the roots of wheat.

[0056] Figure 7 Figure is the detection condition optimization result chart of AIE-MOF probe; wherein, A is the relationship between fluorescence signal change rate ((F0-F) / F0) of AIE-MOF / AA / AAox / chlorpyrifos system and AAox activity; B is the relationship between 427 nm fluorescence intensity of AIE-MOF / AA / AAox / chlorpyrifos system and reaction time.

[0057] Figure 8Figure 1 shows the results of investigating the selectivity and anti-interference ability of the AIE-MOF probe; where A is the fluorescence intensity change of atrazine, carbaryl, diazinon, fenitrothion, phosalone, malathion and chlorpyrifos (all at a final concentration of 1 mg L -1 ) ; B is the fluorescence intensity of the AIE-MOF / AA / AAOx system before (gray) and after (orange) adding 1 mg L -1 chlorpyrifos (orange), and the interference substances include Na + , K + , Mg 2+ , Zn 2+ , Ca 2+ , Cl - and SO4 2- (50 μM). DETAILED DESCRIPTION

[0058] Example 1

[0059] As shown in Figure 1 , the AIE-MOF probe was prepared by one-pot solvent method, and the steps were as follows:

[0060] Manganese chloride tetrahydrate (50 mg) and 1,1,2,2-tetrakis (4-carboxyphenyl) ethylene (25 mg) were dissolved in 7.5 mL N,N-dimethylacetamide, 1 mL acetic acid was added, and the mixture was mixed well; the mixture was placed in a polytetrafluoroethylene-lined autoclave, heated to 120 °C, and reacted at 120 °C for 16 hours. After the reaction was completed, it was cooled to room temperature, centrifuged at 10,000 rpm for 10 minutes, the supernatant was discarded, and the precipitate was washed with acetonitrile to remove unreacted raw materials and generated by-products, a total of three times. At this time, new acetonitrile was added, and there was no color change in the acetonitrile, and the AIE-MOF probe was obtained. The AIE-MOF probe was a light yellow needle-shaped crystal. The AIE-MOF probe was suspended in acetonitrile, and the concentration was about 2.5 mg mL -1 .

[0061] The prepared AIE-MOF probe was characterized.

[0062] The transmission electron microscope (TEM) image of the AIE-MOF probe showed that the AIE-MOF probe was in the form of a hexagonal sheet with a diameter of about 500 nm Figure 3 A), which was consistent with the diameter of 620 nm obtained by dynamic light scattering (DLS) analysis Figure 3 B). In the X-ray diffraction pattern of the AIE-MOF probe, the peaks observed at about 6.9°, 9.7°, 14.1° and 17.1° of 2θ corresponded to (110), (200), (002) and (202) crystal faces, respectively, which were consistent with the simulation data Figure 3C) confirmed the existence of the crystal structure of the AIE-MOF probe. The Fourier transform infrared (FT-IR) spectrum of the AIE-MOF probe showed the characteristic peak of the organic ligand H4TCPE at 1600 cm⁻¹. -1 and 1546cm -1 The strong peak at 1359 cm⁻¹ is from the benzene ring. -1 There is a moderate peak at 1398 cm⁻¹ for CH; simultaneously, at 1398 cm⁻¹... -1 The strong peak appearing at this point is due to the CO-Mn stretching vibration, indicating the presence of a metal ion-carboxylate coordination bond. Figure 3 D). From the full X-ray photoelectron spectroscopy (XPS) spectrum of the AIE-MOF probe ( Figure 3 Fine spectra of E) and X-ray photoelectron spectroscopy (XPS) Figure 3 F) It can be seen that divalent and trivalent manganese coexist in the AIE-MOF probe.

[0063] The above characterizations all demonstrate that the present invention successfully prepared the AIE-MOF probe.

[0064] Example 2

[0065] A method for detecting ascorbic acid oxidase using a fluorescence sensing system based on AIE-MOF probes, comprising the following steps:

[0066] Step (1): Prepare the AIE-MOF probe according to Example 1. Suspend the AIE-MOF probe in acetonitrile to a concentration of approximately 2.5 mg·mL⁻¹. -1 Then dilute it 4 times with ultrapure water to obtain a concentration of 625 mg·L⁻¹. -1 AIE-MOF probe dispersion;

[0067] Step (2) Constructing a fluorescence sensing system: Ascorbate oxidase solutions with different enzyme activities (0, 0.01, 0.05, 0.1, 0.5, 1, 5, 8 U·mL) were prepared using ultrapure water. -1 Ascorbic acid solution (10 mM); different concentrations of ascorbic acid oxidase solution (20 μL, 0, 0.01, 0.05, 0.1, 0.5, 1, 5, 8 U·mL) were added to phosphate buffered saline (PBS, 20 μL, 10 mM, pH = 7.0). -1 The reaction mixture was incubated with ascorbic acid solution (20 μL, 10 mM) and ultrapure water (120 μL) at 37 °C for 40 minutes; then, AIE-MOF probe dispersion (20 μL, 625 mg·L⁻¹) was added to the reaction system. -1 The reaction was carried out at 37℃ for 20 minutes to obtain the AIE-MOF / AA system. A multi-label detection system was used with an excitation wavelength of 348 nm to measure the fluorescence intensity of the AIE-MOF / AA system at 427 nm.Figure 4 A), with the log value of ascorbate oxidase enzyme activity (C AAox ) as the abscissa and the fluorescence intensity (F) at 427 nm as the ordinate, to establish an ascorbate oxidase standard curve (B) Figure 4 B): F = 1343685 - 3117963 x log C AAox (R 2 = 0.999) in the range of 0-0.8 U mL -1 has good linear relationship;

[0068] Step (3), detecting ascorbate oxidase in the sample based on the fluorescence sensing system; the fluorescence intensity of the unknown ascorbate oxidase activity sample measured in step (2) at 427 nm under excitation wavelength of 348 nm, the specific method is as follows: adding the sample to be tested (20 μL), ascorbic acid solution (20 μL, 10 mM) and ultrapure water (120 μL) in the phosphate buffered saline solution (20 μL, 10 mM, pH = 7.0), incubating at 37°C for 40 minutes; then adding AIE-MOF probe dispersion (20 μL, 625 mg·L -1 ) to the reaction system, reacting at 37°C for 20 minutes to obtain AIE-MOF / AA system, using multi-label detection system, measuring the fluorescence intensity of AIE-MOF / AA system at 427 nm under excitation wavelength of 348 nm; substituting the fluorescence intensity into the ascorbate oxidase standard curve of step (2) to obtain the concentration of ascorbate oxidase in the sample to be tested.

[0069] Example 3

[0070] An added recovery experiment for detecting chlorpyrifos based on the fluorescence sensing system constructed by AIE-MOF probe, comprising the following steps:

[0071] Step (1), preparing AIE-MOF probe according to example 1, suspending AIE-MOF probe in acetonitrile, and then diluting with ultrapure water to obtain AIE-MOF probe dispersion with a concentration of 625 mg·L -1 ;

[0072] Step (2), constructing fluorescence sensing system: using methanol to prepare chlorpyrifos methanol solution with different concentrations (0, 0.05, 0.1, 0.5, 1, 5, 50 mg·mL -1 ), using ultrapure water to prepare ascorbate oxidase aqueous solution (2 U·mL -1 ), ascorbic acid aqueous solution (10 mM); adding chlorpyrifos methanol solution with different concentrations (20 μL, 0, 0.05, 0.1, 0.5, 1, 5, 50 mg·L-1 ), ascorbate oxidase aqueous solution (20 μL, 2 U·mL -1 ) was added, and the reaction was allowed to proceed at 37 °C for 60 min. Then, ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL) were added, and the incubation was allowed to proceed at 37 °C for 40 min. Subsequently, the dispersion of AIE-MOF probe (20 μL, 625 mg·L -1 ) was added to the reaction system, and the reaction was allowed to proceed at 37 °C for 20 min to obtain the AIE-MOF / AA / AAox / chlorpyrifos system. The fluorescence intensity of the AIE-MOF / AA / AAox / chlorpyrifos system at 427 nm was measured using a multi-label detection system with 348 nm as the excitation wavelength (F Figure 5 A), and the standard curve of chlorpyrifos (C chlorpyrifos ) was established with the log value of the concentration of chlorpyrifos as the abscissa and the fluorescence intensity at 427 nm as the ordinate (F Figure 5 B). The linear equation was F = 8733676 + 2036536 x log C chlorpyrifos (R 2 = 0.998).

[0073] Step (3), chlorpyrifos addition recovery experiment in wheat samples: the wheat sample was divided into the aboveground part and the root, and was ground into powder by liquid nitrogen respectively; 2 g of the aboveground part / root powder was weighed, and then 2, 5, 10 mg·L -1 of chlorpyrifos methanol solution (100 μL, i.e. 0.1, 0.5 and 1.0 mg·kg -1 of chlorpyrifos added to the sample respectively) was added dropwise to the powder respectively, and was shaken uniformly, and was left to stand for 30 min; acetonitrile-water mixed solvent (10 mL of acetonitrile and 5 mL of water) was used for shaking extraction at room temperature for 1 h, and was centrifuged at 4000 x g for 8 min, and the supernatant was taken, and part of the supernatant was diluted 5 times with water, and was moved into a centrifuge tube containing 80 mg of CNWBOND HC-C18 QuEChERS special ultraclean filler, and was shaken for 2 min, and was low-speed centrifuged for 2 min, and was filtered through a 0.22 μm organic filter membrane to obtain the chlorpyrifos addition recovery test sample;

[0074] Step (4), the chlorpyrifos addition recovery test sample (20 μL) was added to the phosphate buffer solution (20 μL, 10 mM, pH = 7.0), and ascorbate oxidase aqueous solution (20 μL, 2 U·mL -1 ) was added, and the reaction was allowed to proceed at 37 °C for 60 min. Then, ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL) were added, and the incubation was allowed to proceed at 37 °C for 40 min. Subsequently, the dispersion of AIE-MOF probe (20 μL, 625 mg·L -1The dispersion of α-phosphorus ...

[0075] Table 1. Recovery rates of chlorpyrifos in wheat samples

[0076]

[0077] Example 4

[0078] A method for detecting the accumulation of chlorpyrifos in crops using a fluorescence sensing system based on AIE-MOF probes includes the following steps:

[0079] Step (1): Prepare the AIE-MOF probe according to Example 1. Suspend the AIE-MOF probe in acetonitrile and then dilute it with ultrapure water to obtain a concentration of 625 mg·L⁻¹. -1 AIE-MOF probe dispersion;

[0080] Step (2): Construct a fluorescence sensing system according to step (2) of Example 3: Add methanol solutions of different concentrations of chlorpyrifos (20 μL, 0, 0.05, 0.1, 0.5, 1, 5, 50 mg·L⁻¹) to phosphate buffered saline solution (PBS, 20 μL, 10 mM, pH = 7.0). -1 Ascorbic acid oxidase aqueous solution (20 μL, 2 U mL) -1 The reaction was carried out at 37°C for 60 minutes, then ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL) were added, and the mixture was incubated at 37°C for 40 minutes; subsequently, AIE-MOF probe dispersion (20 μL, 625 mg·L⁻¹) was added to the reaction system. -1 The reaction was carried out at 37℃ for 20 minutes to obtain the AIE-MOF / AA / AAox / chlorpyrifos system. A multi-label detection system was used with 348nm as the excitation wavelength to measure the fluorescence intensity of the AIE-MOF / AA / AAox / chlorpyrifos system at 427nm. A chlorpyrifos standard curve was established with the log value of the chlorpyrifos concentration on the x-axis and the fluorescence intensity at 427nm on the y-axis.

[0081] Step (3), taking wheat chlorpyrifos detection as an example, after disinfecting and sterilizing the wheat seeds, germinate in an incubator (set conditions for 30℃ / 25℃ day and night temperature cycle and 14 hours / 10 hours light / dark light period) for 24 hours; after germination, cultivate the seeds in 1 / 2 concentration Hoagland nutrient solution under the same temperature and light conditions for 10 days (change water every 2 days); then add chlorpyrifos solution to the nutrient solution, so that the final concentration of chlorpyrifos in the nutrient solution is 0, 0.2, 0.6, 1.0, 1.4 mg·L -1 , cultivate for 6 days (change water every 2 days); divide the wheat plants into aboveground parts and roots, and grind into powder respectively by liquid nitrogen; weigh 2 g of aboveground part / root powder, add acetonitrile-water mixed solvent (10 mL acetonitrile, 5 mL water), shake extraction at room temperature for 1 hour, then add 2 g of sodium chloride, continue to extract for 15 minutes, centrifuge at 4000 x g for 8 min, take the supernatant, dilute part of the supernatant with water by 5 times, and move into a centrifuge tube containing 80 mg of CNWBOND HC-C18 QuEChERS special ultra-clean filler, shake for 2 minutes, low-speed centrifuge for 2 minutes, pass through 0.22 μm organic filter membrane, and obtain the unknown chlorpyrifos concentration sample to be tested;

[0082] Step (4), add the unknown chlorpyrifos concentration sample to be tested (20 μL) and ascorbic acid oxidase aqueous solution (20 μL, 2 U·mL -1 ) in phosphate buffered saline solution (20 μL, 10 mM, pH = 7.0), react at a temperature of 37℃ for 60 minutes, then add ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL), incubate at a temperature of 37℃ for 40 minutes; then add AIE-MOF probe dispersion (20 μL, 625 mg·L -1 ) to the reaction system, react at a temperature of 37℃ for 20 minutes, obtain the AIE-MOF / AA / AAox / chlorpyrifos system, record the fluorescence intensity of the AIE-MOF / AA / AAox / chlorpyrifos system at 427 nm under the excitation wavelength of 348 nm, and substitute the fluorescence intensity into the chlorpyrifos standard curve of step (2) to obtain the concentration of chlorpyrifos in the sample to be tested, and compare with the result measured by high performance liquid chromatography, and the results are shown in Figure 6 As compared with high performance liquid chromatography, the method is simple in operation, can detect in large quantities, and only needs a small amount of solvent, and is more green and environmentally friendly.

[0083] The high performance liquid chromatography conditions are: the chromatographic column is C18 (250 mm x 4.6 mm), the mobile phase is acetonitrile: water (55:45, by volume), the flow rate is 1 mL min -1 , and the detection wavelength is 230 nm.

[0084] Example 5

[0085] Optimization of detection conditions of the fluorescence sensing system based on AIE-MOF probe

[0086] In phosphate buffer solution (20 μL, 10 mM, pH = 7.0), different concentrations of ascorbate oxidase aqueous solution (20 μL, 1, 2, 5, 8 U·mL -1 ) and methanol (20 μL) were added, and incubated at 37℃ for 60 min; then ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL) were added, and incubated at 37℃ for 40 min; then AIE-MOF probe dispersion (20 μL, 625 mg·L -1 ) was added to the reaction system, and reacted at 37℃ for 20 min to obtain AIE-MOF / AA / AAox system, and then the fluorescence intensity of AIE-MOF / AA / AAox system at 427 nm was recorded under excitation wavelength of 348 nm, and recorded as F0.

[0087] In phosphate buffer solution (20 μL, 10 mM, pH = 7.0), different concentrations of ascorbate oxidase aqueous solution (20 μL, 1, 2, 5, 8 U·mL -1 ) and chlorpyrifos methanol solution (20 μL, 50 mg·L -1 ) were added, and incubated at 37℃ for 60 min; then ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL) were added, and incubated at 37℃ for 40 min; then AIE-MOF probe dispersion (20 μL, 625 mg·L -1 ) was added to the reaction system, and reacted at 37℃ for 20 min to obtain AIE-MOF / AA / AAox / chlorpyrifos system, and then the fluorescence intensity of AIE-MOF / AA / AAox / chlorpyrifos system at 427 nm was recorded under excitation wavelength of 348 nm, and recorded as F.

[0088] The fluorescence signal change ratio ((F-F0) / F0) of AIE-MOF / AA / AAox / chlorpyrifos system was calculated.

[0089] The results are shown in Figure 7 A, which shows that when the activity of ascorbate oxidase is 0.2 U·mL -1 , the fluorescence signal change ratio of AIE-MOF / AA / AAox / chlorpyrifos system reaches the maximum value. Therefore, the activity of ascorbate oxidase is finally selected as 0.2 U·mL -1 as the best condition.

[0090] Example 6

[0091] Optimization of reaction time of ascorbate oxidase and chlorpyrifos

[0092] Ascorbate oxidase aqueous solution (20 μL, 2 U·mL -1 ) and chlorpyrifos methanol solution (20 μL, 50 mg·L -1 ) were added in phosphate buffer solution (20 μL, 10 mM, pH = 7.0) and incubated at 37℃ for 0, 5, 10, 20, 30, 40, 60, 80 min, respectively; then ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL) were added and incubated at 37℃ for 40 min; subsequently, AIE-MOF probe dispersion (20 μL, 625 mg·L -1 ) was added into the reaction system and reacted at 37℃ for 20 min to obtain AIE-MOF / AA / AAox / chlorpyrifos system. The fluorescence intensity of AIE-MOF / AA / AAox / chlorpyrifos system at 427 nm was recorded with 348 nm as excitation wavelength.

[0093] The results are shown in Figure 7 B, which shows that the fluorescence intensity of AIE-MOF / AA / AAox / chlorpyrifos system reaches the maximum value when ascorbate oxidase and chlorpyrifos react for 60 min, and the fluorescence intensity no longer increases with the increase of reaction time; therefore, the reaction time of ascorbate oxidase and chlorpyrifos is selected as 60 min as the optimal condition.

[0094] Example 7

[0095] Investigation of selectivity of AIE-MOF / AA / AAox system to chlorpyrifos

[0096] Ascorbate oxidase aqueous solution (20 μL, 2 U·mL -1 ) and other pesticides (Atrazine, Carbaryl, Diazinon, Fenitrothion, Pyridaphenthione, Malathion) or chlorpyrifos methanol solution (20 μL, 10 mg·L -1 ) were added in phosphate buffer solution (20 μL, 10 mM, pH = 7.0) and incubated at 37℃ for 60 min, respectively; then ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (100 μL) were added and incubated at 37℃ for 40 min; subsequently, AIE-MOF probe dispersion (20 μL, 625 mg·L -1), and the fluorescence intensity of AIE-MOF / AA / AAox / pesticide system at 427 nm was recorded with 348 nm as the excitation wavelength. At the same time, the fluorescence intensity of AIE-MOF / AA / AAox system without adding pesticide at 427 nm was recorded with 348 nm as the excitation wavelength.

[0097] The results are shown in Table 1. Figure 8 A. Compared with the ΔF (ΔF = F-F0) of chlorpyrifos, the above-mentioned six control pesticides had relatively weak effects on the AIE-MOF / AA / AAox system. The signal change caused by chlorpyrifos was more than 5 times that of atrazine, fenitrothion and malathion, while the signal change caused by carbosulfan and diazinon was only about 6.76% and 7.30% of that of chlorpyrifos, respectively. In addition, the response of the sensing system to pyridapenthion similar in structure to chlorpyrifos was only 32.25% of that of chlorpyrifos. The above results show that the AIE-MOF / AA / AAox system has good selectivity for chlorpyrifos.

[0098] Example 8

[0099] Investigation of the anti-ion interference ability of AIE-MOF / AA / AAox and AIE-MOF / AA / AAox / chlorpyrifos system

[0100] In the phosphate buffer solution (20 μL, 10 mM, pH = 7.0), ascorbic acid oxidase aqueous solution (20 μL, 2 U·mL -1 ) and methanol (20 μL) were added, and incubated at 37°C for 60 min. Ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (90 μL) were added, and then Na + , K + , Mg 2+ , Zn 2+ , Ca 2+ , Cl - or SO4 2- aqueous solution (10 μL, 1 mM) was added, and incubated at 37°C for 40 min; then AIE-MOF probe dispersion (20 μL, 625 mg·L -1 ) was added to the reaction system, and reacted at 37°C for 20 min to obtain AIE-MOF / AA / AAox system. The fluorescence intensity of AIE-MOF / AA / AAox system at 427 nm was recorded with 348 nm as the excitation wavelength.

[0101] In the phosphate buffer solution (20 μL, 10 mM, pH = 7.0), ascorbic acid oxidase aqueous solution (20 μL, 2 U·mL -1) with a methanol solution of chlorpyrifos (20 μL, 10 mg·L -1 ), incubated at 37℃ for 60 min, added with an ascorbic acid aqueous solution (20 μL, 10 mM) and ultrapure water (90 μL), and then added with an aqueous solution of Na + ,K + ,Mg 2+ ,Zn 2+ ,Ca 2+ ,Cl - or SO4 2- (10 μL, 1 mM), incubated at 37℃ for 40 min; then added with an AIE-MOF probe dispersion (20 μL, 625 mg·L -1 ) at 37℃ for 20 min to obtain the AIE-MOF / AA / AAox / chlorpyrifos system, and the fluorescence intensity of the AIE-MOF / AA / AAox / chlorpyrifos system at 427 nm was recorded with 348 nm as the excitation wavelength.

[0102] The results are shown in Figure 8 B, in the AIE-MOF / AA / AAox system, the signal change rates caused by these interference ions were all less than 3.9% compared with the blank group. In the AIE-MOF / AA / AAox / chlorpyrifos system, even in the presence of various interference ions, the fluorescence intensity response of the AIE-MOF / AA / AAox / chlorpyrifos system to chlorpyrifos was not affected. The above results demonstrate that the AIE-MOF / AA / AAox / chlorpyrifos system has good anti-ion interference ability.

Claims

1. An application of aggregation-induced emission-metal-organic framework probes in the preparation of a fluorescence sensing system for detecting ascorbic acid oxidase, wherein the fluorescence sensing system for detecting ascorbic acid oxidase is characterized by: Includes the following steps: Step (1): Disperse the aggregation-induced emission-metal-organic framework probe in acetonitrile and dilute it with ultrapure water to obtain an aggregation-induced emission-metal-organic framework probe dispersion, or disperse the aggregation-induced emission-metal-organic framework probe in ultrapure water to obtain an aggregation-induced emission-metal-organic framework probe dispersion; wherein, the aggregation-induced emission-metal-organic framework probe is prepared by a one-pot solvothermal method with manganese chloride tetrahydrate as the metal center and 1,1,2,2-tetra(4-carboxyphenyl)ethylene as the organic ligand; Step (2) Constructing a fluorescence sensing system: Add aqueous solutions of ascorbic acid oxidase with different enzyme activities, aqueous solutions of ascorbic acid, and ultrapure water to phosphate buffer solution, and incubate at 35-40 °C for 30-50 minutes. Add aggregation-induced emission-metal-organic framework probe dispersion to the reaction system and react at 35-40 °C for 15-30 minutes to obtain the detection system. Use 348 nm as the excitation wavelength to measure the fluorescence intensity of the detection system at 427 nm. Plot the enzyme activity of ascorbic acid oxidase or its log value on the x-axis and the fluorescence intensity at 427 nm on the y-axis to establish a standard curve for ascorbic acid oxidase. Step (3) Sample detection: According to step (2), the fluorescence intensity of the unknown ascorbic acid oxidase in the test sample at 427 nm when the excitation wavelength is 348 nm is measured. The fluorescence intensity is substituted into the ascorbic acid oxidase standard curve in step (2) to obtain the concentration of ascorbic acid oxidase in the test sample.

2. The application according to claim 1, characterized in that: In step (1), the aggregation-induced emission-metal-organic framework probe is prepared by dissolving manganese chloride tetrahydrate and 1,1,2,2-tetra(4-carboxyphenyl)ethylene in N,N-diethylacetamide, adding an appropriate amount of acetic acid, mixing well, and reacting at 100-120 °C for 12-16 hours. After the reaction, the sample is centrifuged, the supernatant is discarded, and the precipitate is washed with acetonitrile to obtain the aggregation-induced emission-metal-organic framework probe. The molar ratio of manganese chloride tetrahydrate to 1,1,2,2-tetra(4-carboxyphenyl)ethylene is 5:1 to 5.15:

1. The molar ratio of acetic acid to 1,1,2,2-tetra(4-carboxyphenyl)ethylene is 1:20 to 1:30 mL / mg. The mass-volume ratio of 1,1,2,2-tetra(4-carboxyphenyl)ethylene to N,N-diethylacetamide is 10:1 to 5:1 mg / mL.

3. The application according to claim 1, characterized in that: In step (2), the pH of the phosphate buffer solution is 6.5 to 7.

4.

4. The application according to claim 3, characterized in that: In step (2), the pH of the phosphate buffer solution is 7.

5. The application according to claim 1, characterized in that: In step (2), the final concentration of ascorbic acid in the detection system is 0.5–1.5 mM; the final concentration of the aggregation-induced emission-metal-organic framework probe is 50–100 mg·L⁻¹. -1 The final concentration of ascorbic acid oxidase was 0.001–0.8 U·mL. -1 .

6. The application according to claim 5, characterized in that: In step (2), the final concentration of ascorbic acid in the detection system is 1 mM.

7. The application according to claim 5, characterized in that: In step (2), the final concentration of the aggregation-induced emission-metal-organic framework probe in the detection system is 62.5 mg·L⁻¹. -1 .

8. A method for detecting chlorpyrifos using a fluorescence sensing system based on aggregation-induced emission-metal-organic framework probes, characterized in that: Includes the following steps: Step (1): Disperse the aggregation-induced emission-metal-organic framework probe in acetonitrile and dilute it with ultrapure water to obtain an aggregation-induced emission-metal-organic framework probe dispersion, or disperse the aggregation-induced emission-metal-organic framework probe in ultrapure water to obtain an aggregation-induced emission-metal-organic framework probe dispersion; wherein, the aggregation-induced emission-metal-organic framework probe is prepared by a one-pot solvothermal method with manganese chloride tetrahydrate as the metal center and 1,1,2,2-tetra(4-carboxyphenyl)ethylene as the organic ligand; Step (2) Constructing a fluorescence sensing system: Add different concentrations of chlorpyrifos methanol or aqueous solution and ascorbic acid oxidase aqueous solution to phosphate buffer solution, incubate at 35-40 ℃ for 50-80 minutes, then add ascorbic acid aqueous solution and ultrapure water to the reaction system, react at 35-40 ℃ for 15-40 minutes, finally add aggregation-induced emission-metal-organic framework probe dispersion to the reaction system, react at 35-40 ℃ for 15-30 minutes to obtain the detection system, use 348 nm as the excitation wavelength, measure the fluorescence intensity of the detection system at 427 nm, and establish a chlorpyrifos standard curve with the concentration of chlorpyrifos or its log value on the x-axis and the fluorescence intensity at 427 nm on the y-axis; Step (3) Sample detection: According to step (2), the fluorescence intensity of the sample with unknown chlorpyrifos concentration at 427 nm when the excitation wavelength is 348 nm is measured. The fluorescence intensity value is substituted into the chlorpyrifos standard curve in step (2) to obtain the concentration of chlorpyrifos in the sample.

9. The method for detecting chlorpyrifos according to claim 8, characterized in that: In step (1), the aggregation-induced emission-metal-organic framework probe is prepared by dissolving manganese chloride tetrahydrate and 1,1,2,2-tetra(4-carboxyphenyl)ethylene in N,N-diethylacetamide, adding an appropriate amount of acetic acid, mixing well, and reacting at 100-120 °C for 12-16 hours. After the reaction, the sample is centrifuged, the supernatant is discarded, and the precipitate is washed with acetonitrile to obtain the aggregation-induced emission-metal-organic framework probe. The molar ratio of manganese chloride tetrahydrate to 1,1,2,2-tetra(4-carboxyphenyl)ethylene is 5:1 to 5.15:

1. The molar ratio of acetic acid to 1,1,2,2-tetra(4-carboxyphenyl)ethylene is 1:20 to 1:30 mL / mg. The mass-volume ratio of 1,1,2,2-tetra(4-carboxyphenyl)ethylene to N,N-diethylacetamide is 10:1 to 5:1 mg / mL.

10. The method for detecting chlorpyrifos according to claim 8, characterized in that: In step (2), the pH of the phosphate buffer solution is 6.5 to 7.

4.

11. The method for detecting chlorpyrifos according to claim 10, characterized in that: In step (2), the pH of the phosphate buffer solution is 7.

12. The method for detecting chlorpyrifos according to claim 8, characterized in that: In step (2), the ascorbic acid oxidase activity in the detection system is 0.1–0.8 U·mL. -1 The final concentration of ascorbic acid was 0.5–1.5 mM; the final concentration of the aggregation-induced emission-metal-organic framework probe was 50–100 mg·L⁻¹. -1 The final concentration of chlorpyrifos is 0.005–5 mg / L. -1 .

13. The method for detecting chlorpyrifos according to claim 12, characterized in that: In step (2), the ascorbic acid oxidase activity in the detection system is 0.2 U·mL. -1 .

14. The method for detecting chlorpyrifos according to claim 12, characterized in that: In step (2), the final concentration of ascorbic acid in the detection system is 1 mM.

15. The method for detecting chlorpyrifos according to claim 12, characterized in that: In step (2), the final concentration of the aggregation-induced emission-metal-organic framework probe in the detection system is 62.5 mg·L⁻¹. -1 .

16. The method for detecting chlorpyrifos according to claim 8, characterized in that: In step (2), the construction of the fluorescence sensing system involves adding different concentrations of chlorpyrifos methanol solution and ascorbic acid oxidase aqueous solution to a phosphate buffer solution, incubating at 35–40 °C for 60–80 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at 35–40 °C for 15–40 minutes, and finally adding AIE-MOF probe dispersion to the reaction system, reacting at 35–40 °C for 15–40 minutes to obtain the detection system.

17. The method for detecting chlorpyrifos according to claim 8 or 16, characterized in that: In step (2), the construction of the fluorescence sensing system involves adding different concentrations of chlorpyrifos methanol solution and ascorbic acid oxidase aqueous solution to a phosphate buffer solution, incubating at 37 °C for 60 minutes, then adding ascorbic acid aqueous solution and ultrapure water to the reaction system, reacting at 37 °C for 40 minutes, and finally adding AIE-MOF probe dispersion to the reaction system, reacting at 37 °C for 20 minutes to obtain the detection system.

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