Preparation method and application of bimetallic nano-enzyme induced MOFs (at) CDs material

Abstract

The invention discloses a preparation method and application of a bimetallic nano-enzyme induced MOFs (at) CDs material, and the preparation method at least comprises the following steps: I, dissolving FeCl3, CoCl2 and 2-aminoterephthalic acid in N, N '-dimethylformamide to form a mixed solution I, and carrying out a reaction I to obtain a bimetallic MOFs material; step II, mixing tricarballylic acid and m-phenylenediamine, and carrying out a reaction II to obtain carbon dot powder; step III, dissolving the carbon dot powder obtained in the step II in methanol, and adding rhodamine B dye to obtain a CDs material; and IV, dissolving the bimetallic MOFs material obtained in the step I and the CDs material obtained in the step III in water, stirring, and drying to obtain the MOFs (at) CDs material. The synthesized nano-enzyme is simple to prepare and high in catalytic activity, the carbon dot material is encapsulated into the MOFs material, the fluorescence characteristic of the MOFs material is enhanced, and the carbon dot material is combined with o-phenylenediamine to be used for detecting H2O2.

Description

A method for preparing and applying bimetallic nanozyme-induced MOFs@CDs materials Technical Field

[0001] This application relates to a method for preparing and applying bimetallic nanozyme-induced MOFs@CDs materials, belonging to the field of environmental monitoring technology. Background Technology

[0002] Hydrogen peroxide (H2O2) plays a crucial role as a bioactive molecule in living systems. Within cells, H2O2 acts as a signaling molecule, participating in the regulation of various physiological processes. Low concentrations of H2O2 can stimulate cell growth and differentiation, promoting tissue development and repair. However, excessive accumulation of H2O2 in living systems disrupts normal cellular metabolism and causes protein denaturation, polymerization, or breakage, thereby affecting normal protein function. Furthermore, excessive H2O2 can cause DNA strand breaks, base modifications, and cross-linking, potentially leading to serious consequences such as gene mutations and chromosomal aberrations. Long-term accumulation of DNA damage may also increase the risk of cell carcinogenesis. Therefore, developing an efficient and sensitive method for detecting H2O2 is of paramount importance.

[0003] The high cost and easy inactivation of natural enzymes limit their practical applications. In recent years, nanozymes have rapidly developed due to their excellent physicochemical properties, ease of storage, low cost, and high stability. Metal-organic frameworks (MOFs) are a class of crystalline porous materials with periodic network structures, possessing advantages such as large specific surface area and tunable structure, making them ideal materials for constructing nanozymes. Through the synergistic effect between two metals, bimetallic MOF materials can exhibit superior enzyme catalytic activity. Furthermore, since the improvement in enzyme catalytic activity is limited, combining catalytic properties with the fluorescence properties of MOF materials is an effective means to enhance detection sensitivity. Summary of the Invention

[0004] To achieve highly sensitive detection of H2O2, carbon dot materials are encapsulated in bimetallic nanozyme materials to form a dual-emission ratio fluorescent probe. After adding o-phenylenediamine, combined with the catalytic and fluorescence properties of the material, triple emission of H2O2 is achieved, thereby improving the detection sensitivity of H2O2.

[0005] The purpose of this invention is to develop a bimetallic nanozyme-induced ratiometric fluorescence sensor for highly sensitive detection of H2O2.

[0006] To this end, this invention first prepares a bimetallic MOF material, then synthesizes a carbon dot material, and then mixes and stirs the carbon dot material with the bimetallic MOF material to prepare a fluorescent probe. The fluorescent probe is then combined with o-phenylenediamine to achieve the detection of H2O2.

[0007] According to one aspect of this application, a method for preparing bimetallic nanozyme-induced MOFs@CDs materials is provided, the preparation method comprising at least the following steps:

[0008] Step I: FeCl3, CoCl2 and 2-aminoterephthalic acid are dissolved in N,N'-dimethylformamide to form mixed solution I, reaction I, to obtain bimetallic MOF materials;

[0009] Step II: Mix trimalonic acid and m-phenylenediamine, react II, and obtain carbon dot powder;

[0010] Step III: Disperse the carbon dot powder obtained in Step II in methanol, add Rhodamine B dye, and obtain CDs material;

[0011] Step IV: Mix the bimetallic MOFs material obtained in Step I with the CDs material obtained in Step III, stir, wash, and dry to obtain MOFs@CDs material.

[0012] Optionally, in step I, the molar ratio of FeCl3 to CoCl2 is 1:1 to 2:3.

[0013] Optionally, in step I, the molar ratio of FeCl3 to CoCl2 is independently selected from any value among 1:1, 1.5:1, 2:1, 2:2.5, and 2:3, or a range between any two of the above.

[0014] In the mixed solution I, the concentration of FeCl3 is 0.0125–0.1 mol / L;

[0015] In the mixed solution I, the concentration of 2-aminoterephthalic acid is 0.0125–0.1 mol / L.

[0016] Optionally, the amount of FeCl3 is 0.5 mmol to 2.0 mmol.

[0017] Optionally, the amount of 2-aminoterephthalic acid is 0.5 mmol to 2.0 mmol.

[0018] Optionally, the volume of the N,N'-dimethylformamide shown is 20 to 40 mL.

[0019] Optionally, in step I, the conditions for reaction I are as follows:

[0020] The temperature of reaction I is 80–160°C;

[0021] The reaction time for reaction I is 12–24 h.

[0022] Optionally, in step II, the molar ratio of triamic acid to m-phenylenediamine is 1:1 to 5:1.

[0023] Optionally, in step II, the molar ratio of triamic acid and m-phenylenediamine is independently selected from any value among 1:1, 2:1, 3:1, 4:1, 5:1 or any range between any two of the above.

[0024] Optionally, the amount of m-phenylenediamine is 0.5 mmol to 2.0 mmol.

[0025] Optionally, in step II, the conditions for reaction II are as follows:

[0026] The temperature of reaction II is 200–250°C;

[0027] The reaction time for reaction II is 2 to 6 hours.

[0028] Optionally, in step III, the mass concentration of Rhodamine B in the CDs material is 1.0–6.0 mg.

[0029] Optionally, in step IV, the mass ratio of the bimetallic MOFs material to the CDs material is 1:1 to 1:6;

[0030] Optionally, the mass concentration of the CDs material in the water is 0.5–6 g / L;

[0031] The stirring time is 12 to 24 hours;

[0032] The drying temperature is 25–60°C;

[0033] The drying time is 6 to 24 hours.

[0034] According to another aspect of this application, an application of MOFs@CDs material in H2O2 detection is provided, which involves mixing a solution containing MOFs@CDs material, an H2O2 solution, and an o-phenylenediamine solution, adding a buffer solution, reacting, and then testing the absorbance.

[0035] Optionally, the concentration of MOFs@CDs material in the solution containing MOFs@CDs material is 0.5–2.0 mg / mL;

[0036] The concentration of the H2O2 solution is 1–10 mM;

[0037] The concentration of the o-phenylenediamine solution is 1–20 mM;

[0038] Optionally, the buffer solution is selected from at least one of HAc-NaAc buffer solution and phosphate buffer solution.

[0039] Optionally, the reaction conditions are as follows:

[0040] The reaction temperature is 25–37°C;

[0041] The reaction time is 10 to 100 minutes.

[0042] The beneficial effects that this application can produce include:

[0043] 1) The fluorescent probe described in this application combines catalytic performance with fluorescence properties, which can effectively improve the specificity and sensitivity of detection.

[0044] 2) The fluorescent probe provided in this application has high sensitivity and good selectivity, and has broad prospects in biomedicine and environmental monitoring.

[0045] In summary, the simple and efficient preparation of this material has significant scientific and practical value. Attached Figure Description

[0046] Figure 1 is a comparison of the peroxidase activities of the single-metal and bimetal nanozymes of this application;

[0047] Figure 2 shows the peroxidase activity of MOFs materials with different metal ratios in this application;

[0048] Figure 3 shows the fluorescence spectra of MOFs materials with different metal ratios in this application;

[0049] Figure 4 shows the fluorescence spectra of MOFs encapsulated with CDs of different concentrations in this application;

[0050] Figure 5 shows the fluorescence spectra of MOFs@CDs before and after the addition of H2O2. Detailed Implementation

[0051] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0052] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0053] The analysis methods in the embodiments and test examples of this application are as follows:

[0054] The fluorescence spectrum of the probe was tested using a Hitachi F-4600 fluorescence spectrometer;

[0055] The absorbance of the material was measured using a Persee TU-1901 UV-Vis spectrophotometer.

[0056] According to one embodiment of this application, a method for constructing bimetallic MOF nanozymes is provided:

[0057] A certain amount of FeCl3·6H2O, CoCl2·6H2O and 2-aminoterephthalic acid were weighed out in sequence and dissolved in a certain volume of N,N'-dimethylformamide. The mixed solution was stirred at room temperature for a certain time, heated in an oven for a certain time, centrifuged, washed multiple times, and then vacuum dried to obtain MOF materials.

[0058] The molar ratio of FeCl3·6H2O and CoCl2·6H2O is 1:1 to 2:3, wherein the amount of FeCl3·6H2O is 0.5 mmol to 2.0 mmol, the amount of 2-aminoterephthalic acid is 0.5 mmol to 2.0 mmol, and the volume of N,N'-dimethylformamide is 20 to 40 mL.

[0059] According to one embodiment of this application, a method for constructing carbon dot materials is as follows:

[0060] A certain amount of trimalonic acid and m-phenylenediamine were weighed sequentially and finely ground in a mortar and pestle. The powder was then placed in a tube furnace and heated for a certain period of time. After the reaction was completed and the mixture was cooled, a powder sample was obtained. Acetonitrile and dichloromethane were then added to the powder for purification. The purified carbon dot powder was dissolved in methanol solution, and Rhodamine B dye was added. The mixture was stirred at room temperature for a certain period of time, centrifuged, washed, and dried.

[0061] The molar ratio of triamic acid to m-phenylenediamine is 1:1 to 5:1, wherein the amount of m-phenylenediamine is 0.5 mmol to 2.0 mmol, the reaction temperature is 200 to 250 °C, the reaction time is 2 to 6 h, and the content of rhodamine B is 1 mg to 10 mg.

[0062] According to one embodiment of this application, a method for constructing MOFs@CDs is provided:

[0063] A certain amount of MOFs and carbon dot materials were weighed, dissolved in a certain volume of aqueous solution, stirred at room temperature for a certain time, centrifuged, washed, and vacuum dried to obtain MOFs@CDs materials.

[0064] The mass ratio of MOFs to carbon dot materials is 1:1 to 1:6, the mass of carbon dot materials is 10mg to 30mg, the volume of the aqueous solution is 5mL to 20mL, the stirring time is 12 to 24 hours, the drying temperature is room temperature to 60℃, and the drying time is 6 to 24 hours.

[0065] Example 1: Preparation of bimetallic MOF materials (Fe to Co molar ratio of 1:1)

[0066] 0.5 mmol FeCl3·6H2O, 0.5 mmol CoCl2·6H2O and 1.0 mmol 2-aminoterephthalic acid were weighed out sequentially and dissolved in 20 mL of N,N'-dimethylformamide. The mixture was stirred at room temperature for 20 min, heated in an oven at 120 °C for 12 h, centrifuged, washed 5 times with ethanol, and dried in a vacuum oven at 60 °C for 12 h to obtain bimetallic MOF materials. The catalase activity and fluorescence spectrum of the materials are shown in Figures 2 and 3.

[0067] Example 2: Preparation of bimetallic MOF materials (Fe to Co molar ratio of 2:1)

[0068] 1.0 mmol FeCl3·6H2O, 0.5 mmol CoCl2·6H2O, and 1.0 mmol 2-aminoterephthalic acid were weighed sequentially and dissolved in 25 mL of N,N'-dimethylformamide. The mixture was stirred at room temperature for 20 min, heated in an oven at 120 °C for 12 h, centrifuged, washed five times with ethanol, and dried in a vacuum oven at 60 °C for 12 h to obtain bimetallic MOF materials. Their catalase activity and fluorescence spectra are shown in Figures 2 and 3.

[0069] Preparation Example 3: Preparation of bimetallic MOF materials (Molar ratio of Fe to Co: 1:2)

[0070] 0.5 mmol FeCl3·6H2O, 1.0 mmol CoCl2·6H2O, and 1.0 mmol 2-aminoterephthalic acid were weighed sequentially and dissolved in 25 mL of N,N'-dimethylformamide. The mixture was stirred at room temperature for 20 min, heated in an oven at 120 °C for 12 h, centrifuged, washed five times with ethanol, and dried in a vacuum oven at 60 °C for 12 h to obtain bimetallic MOF materials. Their catalase activity and fluorescence spectra are shown in Figures 2 and 3.

[0071] Preparation Example 4: Preparation of bimetallic MOF materials (Molar ratio of Fe to Co: 1:3)

[0072] 0.5 mmol FeCl3·6H2O, 1.5 mmol CoCl2·6H2O, and 1.0 mmol 2-aminoterephthalic acid were weighed sequentially and dissolved in 30 mL of N,N'-dimethylformamide. The mixture was stirred at room temperature for 20 min, heated in an oven at 120 °C for 12 h, centrifuged, washed five times with ethanol, and dried in a vacuum oven at 60 °C for 12 h to obtain bimetallic MOF materials. Their catalase activity and fluorescence spectra are shown in Figures 2 and 3.

[0073] Preparation Example 5: Preparation of bimetallic MOF materials (Fe to Co molar ratio of 2:3)

[0074] 1.0 mmol FeCl3·6H2O, 1.5 mmol CoCl2·6H2O and 1.0 mmol 2-aminoterephthalic acid were weighed out sequentially and dissolved in 30 mL of N,N'-dimethylformamide. The mixture was stirred at room temperature for 20 min, heated in an oven at 120 °C for 12 h, centrifuged, washed 5 times with ethanol, and dried in a vacuum oven at 60 °C for 12 h to obtain bimetallic MOF materials. The catalase activity and fluorescence spectrum of the materials are shown in Figures 2 and 3.

[0075] Preparation Example 6: Preparation of Carbon Dot Materials

[0076] 1.0 mmol of trimalonic acid and 1.0 mmol of m-phenylenediamine were weighed sequentially and finely ground in a mortar. The powder was then heated in a tube furnace at 200 °C for 2 hours. After the reaction was completed and the mixture was cooled, a powder sample was obtained. Acetonitrile and dichloromethane were then added to the powder for purification. The purified carbon dot powder was dissolved in methanol solution, and 1 mg of rhodamine B dye was added. The mixture was stirred at room temperature for 30 min, centrifuged, washed, and dried.

[0077] Preparation Example 7: Preparation of Carbon Dot Materials

[0078] 2.5 mmol of trimalonic acid and 1.0 mmol of m-phenylenediamine were weighed sequentially and finely ground in a mortar and pestle. The powder was then heated in a tube furnace at 200 °C for 2 hours. After the reaction was completed and the mixture was cooled, a powder sample was obtained. Acetonitrile and dichloromethane were then added to the powder for purification. The purified carbon dot powder was dissolved in methanol solution, and 1 mg of rhodamine B dye was added. The mixture was stirred at room temperature for 30 min, centrifuged, washed, and dried.

[0079] Preparation Example 8: Preparation of Carbon Dot Materials

[0080] 5.0 mmol of trimalonic acid and 1.0 mmol of m-phenylenediamine were weighed sequentially and finely ground in a mortar. The powder was then heated in a tube furnace at 200 °C for 2 hours. After the reaction was completed and the mixture was cooled, a powder sample was obtained. Acetonitrile and dichloromethane were then added to the powder for purification. The purified carbon dot powder was dissolved in methanol solution, and 1 mg of rhodamine B dye was added. The mixture was stirred at room temperature for 30 min, centrifuged, washed, and dried.

[0081] Preparation Example 9: Preparation of Carbon Dot Materials

[0082] 2.5 mmol of trimalonic acid and 1.0 mmol of m-phenylenediamine were weighed sequentially and finely ground in a mortar and pestle. The powder was then heated in a tube furnace at 230 °C for 2 hours. After the reaction was completed and the mixture was cooled, a powder sample was obtained. Acetonitrile and dichloromethane were then added to the powder for purification. The purified carbon dot powder was dissolved in methanol solution, and 1 mg of rhodamine B dye was added. The mixture was stirred at room temperature for 30 min, centrifuged, washed, and dried.

[0083] Preparation Example 10: Preparation of Carbon Dot Materials

[0084] 2.5 mmol of trimalonic acid and 1.0 mmol of m-phenylenediamine were weighed sequentially and finely ground in a mortar and pestle. The powder was then heated in a tube furnace at 230 °C for 2 hours. After the reaction was completed and the mixture was cooled, a powder sample was obtained. Acetonitrile and dichloromethane were then added to the powder for purification. The purified carbon dot powder was dissolved in methanol solution, and 5 mg of rhodamine B dye was added. The mixture was stirred at room temperature for 30 min, centrifuged, washed, and dried.

[0085] Preparation Example 11: Preparation of Carbon Dot Materials

[0086] 2.5 mmol of trimalonic acid and 1.0 mmol of m-phenylenediamine were weighed sequentially and finely ground in a mortar and pestle. The powder was then heated in a tube furnace at 230 °C for 2 hours. After the reaction was completed and the mixture was cooled, a powder sample was obtained. Acetonitrile and dichloromethane were then added to the powder for purification. The purified carbon dot powder was dissolved in methanol solution, and 10 mg of rhodamine B dye was added. The mixture was stirred at room temperature for 30 min, centrifuged, washed, and dried.

[0087] Example 1: Preparation of MOFs@CDs materials

[0088] Weigh 5 mg of the bimetallic MOF material obtained in Preparation Example 1 and 5 mg of the carbon dot material obtained in Preparation Example 10, dissolve them in 5 mL of deionized water, stir at room temperature for 24 hours, centrifuge, wash 5 times with deionized water, and vacuum dry at 60 °C for 12 hours to obtain MOFs@CDs material. Its fluorescence spectrum is shown in Figure 4.

[0089] Example 2: Preparation of MOFs@CDs materials

[0090] Weigh 5 mg of the bimetallic MOF material obtained in Preparation Example 1 and 10 mg of the carbon dot material obtained in Preparation Example 10, dissolve them in 5 mL of deionized water, stir at room temperature for 24 hours, centrifuge, wash 5 times with deionized water, and vacuum dry at 60 °C for 12 hours to obtain MOFs@CDs material. Its fluorescence spectrum is shown in Figure 4.

[0091] Example 3: Preparation of MOFs@CDs materials

[0092] Weigh 5 mg of the bimetallic MOF material obtained in Preparation Example 1 and 15 mg of the carbon dot material obtained in Preparation Example 10, dissolve them in 10 mL of deionized water, stir at room temperature for 24 hours, centrifuge, wash 5 times with deionized water, and vacuum dry at 60 °C for 12 hours to obtain MOFs@CDs material. Its fluorescence spectrum is shown in Figure 4.

[0093] Example 4: Preparation of MOFs@CDs materials

[0094] Weigh 5 mg of the bimetallic MOF material obtained in Preparation Example 1 and 20 mg of the carbon dot material obtained in Preparation Example 10, dissolve them in 15 mL of deionized water, stir at room temperature for 24 hours, centrifuge, wash 5 times with deionized water, and vacuum dry at 60 °C for 12 hours to obtain MOFs@CDs material. Its fluorescence spectrum is shown in Figure 4.

[0095] Example 5: Preparation of MOFs@CDs materials

[0096] Weigh 5 mg of the bimetallic MOF material obtained in Preparation Example 1 and 25 mg of the carbon dot material obtained in Preparation Example 10, dissolve them in 20 mL of deionized water, stir at room temperature for 24 hours, centrifuge, wash 5 times with deionized water, and vacuum dry at 60 °C for 12 hours to obtain MOFs@CDs material. Its fluorescence spectrum is shown in Figure 4.

[0097] Example 6: Preparation of MOFs@CDs materials

[0098] Weigh 5 mg of the bimetallic MOF material obtained in Preparation Example 1 and 30 mg of the carbon dot material obtained in Preparation Example 10, dissolve them in 20 mL of deionized water, stir at room temperature for 24 hours, centrifuge, wash 5 times with deionized water, and vacuum dry at 60 °C for 12 hours to obtain MOFs@CDs material. Its fluorescence spectrum is shown in Figure 4.

[0099] Comparative Example 1 (Unencapsulated carbon quantum dots)

[0100] Using the bimetallic MOF material prepared in Example 1, 100 μL of MOF material (0.01 mg / mL), 80 μL of o-phenylenediamine solution (10 mM), and 80 μL of H2O2 (2.5 mM) were mixed. Then, HAc-NaAc buffer solution (pH = 5.0) was added to the system until the solution volume reached 2.0 mL. The mixture was incubated at 37 °C for 60 min, and the fluorescence spectrum of the mixture was then measured.

[0101] Comparative Example 2

[0102] Weigh 1.0 mmol FeCl3·6H2O and 1.0 mmol 2-aminoterephthalic acid, dissolve them in 30 mL of N,N'-dimethylformamide, stir the mixture at room temperature for 20 min, heat it in an oven at 120 °C for 12 h, centrifuge, wash it 5 times with ethanol, and dry it in a vacuum oven at 60 °C for 12 h to obtain the single metal Fe-MOF material.

[0103] 100 μL of single-metal Fe-MOF material (0.01 mg / mL), 80 μL of o-phenylenediamine solution (10 mM), and 80 μL of H₂O₂ (2.5 mM) were mixed, and then HAc-NaAc buffer solution (pH = 5.0) was added to the system until the solution volume was 2.0 mL. The mixed solution was incubated at 37 °C for 60 min, and then the fluorescence spectrum of the mixed solution was measured.

[0104] Test Example 1

[0105] Using the fluorescent probe prepared in Example 2, 100 μL of MOF material (0.01 mg / mL), 80 μL of o-phenylenediamine solution (10 mM), and 80 μL of H2O2 (2.5 mM) were mixed. Then, HAc-NaAc buffer solution (pH = 5.0) was added to the system until the solution volume reached 2.0 mL. The mixed solution was incubated at 37 °C for 60 min, and the fluorescence spectrum of the mixed solution was then measured. The fluorescence spectra before and after contact with H2O2 are shown in Figure 5.

[0106] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing bimetallic nanozyme-induced MOFs@CDs materials, characterized in that, The preparation method includes at least the following steps: Step I: FeCl3, CoCl2 and 2-aminoterephthalic acid are dissolved in N,N'-dimethylformamide to form mixed solution I, reaction I, to obtain bimetallic MOFs material; Step II: Trimalonic acid and m-phenylenediamine are mixed, reaction II, to obtain carbon dot powder; Step III: The carbon dot powder obtained in Step II is dispersed in methanol, and Rhodamine B dye is added to obtain CDs material; Step IV: The bimetallic MOFs material obtained in Step I and the CDs material obtained in Step III are dissolved in water, stirred, washed and dried to obtain MOFs@CDs material.

2. The preparation method according to claim 1, characterized in that, In step I, the molar ratio of FeCl3 to CoCl2 is 1:1 to 2:3; in the mixed solution I, the concentration of FeCl3 is 0.0125 to 0.1 mol / L; in the mixed solution I, the concentration of 2-aminoterephthalic acid is 0.0125 to 0.1 mol / L.

3. The preparation method according to claim 1, characterized in that, In step I, the conditions for reaction I are as follows: the temperature of reaction I is 80–160°C; the time of reaction I is 12–24 h.

4. The preparation method according to claim 1, characterized in that, In step II, the molar ratio of triamic acid to m-phenylenediamine is 1:1 to 5:

1.

5. The preparation method according to claim 1, characterized in that, In step II, the conditions for reaction II are as follows: the temperature of reaction II is 200-250°C; the time of reaction II is 2-6 hours.

6. The preparation method according to claim 1, characterized in that, In step III, the mass of Rhodamine B in the CDs material is 1.0–6.0 mg.

7. The preparation method according to claim 1, characterized in that, In step IV, the mass ratio of the bimetallic MOFs material to the CDs material is 1:1 to 1:6; preferably, the mass concentration of the CDs material in the water is 0.5 to 6 g / L; the stirring time is 12 to 24 hours; the drying temperature is 25 to 60°C; and the drying time is 6 to 24 hours.

8. An application of MOFs@CDs material in H2O2 detection, characterized in that, A solution containing MOFs@CDs material, an H2O2 solution, and an o-phenylenediamine solution are mixed, a buffer solution is added, the reaction is carried out, and the absorbance is measured; the MOFs@CDs material is prepared by any one of the preparation methods in claims 1 to 7.

9. The application according to claim 8, characterized in that, In the solution containing MOFs@CDs material, the concentration of MOFs@CDs material is 0.5-2 mg / mL; the concentration of H2O2 solution is 1-10 mM; the concentration of o-phenylenediamine solution is 1-20 mM; preferably, the buffer solution is selected from at least one of HAc-NaAc buffer solution and phosphate buffer solution.

10. The application according to claim 8, characterized in that, The reaction conditions are as follows: the reaction temperature is 25–37°C; the reaction time is 10–100 min.

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