Preparation method of a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal organic framework materials

Abstract

The present invention discloses a preparation method of a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal organic framework materials. The method adopts a solvothermal method, wherein metal ions or clusters and organic ligands are mixed in a high-boiling-point solvent and reacted to generate MOF under high temperature conditions. The solid polymer synthesized by this method is composed of the metal ion ammonium cerium nitrate and the organic ligand 2-hydroxyterephthalic acid. The sensor is composed of Ce-MOF, 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 to form a colorimetric and fluorescent dual-response sensor. Based on ultraviolet absorption and fluorescence intensity, H2S is accurately detected. The detection range of the sensor colorimetric response is 200-2300μM, with a detection limit of 0.262μM, and the detection range of the fluorescence response is 16-320μM, with a detection limit of 0.156μM, achieving more accurate detection of H2S and meeting the detection requirements of food freshness and safety.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterial synthesis, and in particular to a method for preparing a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal organic framework materials. Background Art

[0002] Hydrogen sulfide (H2S) is a toxic gas with a rotten-egg smell. It primarily originates from foods containing organic sulfur, such as eggs, meat, fruits, and vegetables. It is often used as an indicator of food spoilage. Although H2S has been reported to aid food storage by regulating physiological metabolism and increasing the activity of antioxidant enzymes, it can also have adverse effects on some foods. For example, H2S produced by brewer's yeast can impair the taste and flavor of wine. In recent years, H2S has been discovered to be the third endogenous signaling molecule after nitric oxide (NO) and carbon monoxide (CO). Endogenous H2S plays a key role in many physiological processes, including cardiovascular function regulation, insulin secretion, neural regulation, and cell apoptosis. However, abnormal H2S levels can lead to diseases such as Alzheimer's disease, Down syndrome, diabetes, and cirrhosis.

[0003] Therefore, there is an urgent need to establish a quantitative and intuitive detection method for H2S, which is crucial for ensuring food safety and human health. Compared with traditional detection methods, metal-organic frameworks have outstanding advantages such as high specific surface area, rich and diverse framework structures, and high crystallinity, which make them more suitable for food safety testing. Summary of the Invention

[0004] Based on this, the present invention discloses a method for preparing a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal-organic framework materials. The method adopts a solvothermal method to solve the problems pointed out in the background technology by mixing metal ions or clusters and organic ligands in a high-boiling point solvent and reacting them under high temperature conditions to generate MOF.

[0005] One object of the present invention is to provide a method for preparing a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal organic framework materials, specifically:

[0006] The reaction solution is obtained by heating, mixing and stirring a solution of ammonium cerium nitrate and 2-hydroxyterephthalic acid;

[0007] The reaction solution is washed, filtered, and dried to obtain a solid polymer A, wherein the washing agent used in the washing is anhydrous ethanol;

[0008] The solid polymer A was added to NaAc-HAc buffer at a concentration of 0.05 mg / mL, and solution A was obtained after ultrasonic oscillation. The peak data of the ultraviolet absorption and fluorescence emission spectra of solution A were detected and recorded. The peak of the ultraviolet absorption appeared at 325±5 nm, and the peak of the fluorescence emission appeared at 410±5 nm.

[0009] Using 3,3',5,5'-tetramethylbenzidine (TMB) as a color development substrate, Ce-MOF, TMB, and H2O2 were mixed to obtain suspension B. The peak data of ultraviolet absorption of suspension B was detected and recorded. The peak of ultraviolet absorption appeared at 652 nm.

[0010] Suspension B was mixed with sodium sulfide solutions of different concentrations to obtain solution B. The peak data of ultraviolet absorption and the peak data of fluorescence emission spectrum of solution B were detected and recorded. The peak of ultraviolet absorption appeared at 652 nm, and the peak of fluorescence emission appeared at 410±5 nm. The functional relationship between different concentrations of sodium sulfide solution in solution B and the ultraviolet absorption peak value, as well as the functional relationship between different concentrations of sodium sulfide solution in solution B and the fluorescence emission peak value, was used to obtain the relationship between different concentrations of sodium sulfide in solution B and the corresponding dual-mode response of solution B to detect hydrogen sulfide.

[0011] Furthermore, the sensor is composed of H2O2, TMB, cerium ammonium nitrate and 2-hydroxyterephthalic acid, and the structures of TMB and 2-hydroxyterephthalic acid are as follows:

[0012]

[0013] Furthermore, 164.5 mg of ammonium cerium nitrate and 109.3 mg of 2-hydroxyterephthalic acid were dissolved in 15 mL of DMF and 45 mL of DMF, respectively, and heated for reaction, and ultrasonicated until completely dissolved.

[0014] Furthermore, a solvothermal method is used to generate MOFs by mixing metal ions or clusters with organic ligands in a high-boiling point solvent and reacting them under high temperature and high pressure conditions.

[0015] Furthermore, the solvothermal method is specifically to synthesize solid polymer A by a solvothermal method, and the solid polymer A synthesis method comprises the following steps:

[0016] S1. Dissolve 164.5 mg of cerium ammonium nitrate and 109.3 mg of 2-hydroxyterephthalic acid in 15 mL of DMF and 45 mL of DMF, respectively, and sonicate until completely dissolved.

[0017] S2. The 2-hydroxyterephthalic acid solution was transferred to a 100 mL round-bottom flask, placed in silicone oil at 120°C, and stirred at 200 rpm using a magnetic stirrer.

[0018] S3. Add 0.6 mL of acetic acid, and then drip the cerium ammonium nitrate solution into the round-bottom flask at a rate of one drop per 3 seconds;

[0019] S4. After the addition is complete, stir for 6 minutes, turn off the magnetic stirrer, and maintain heating at 120°C for 3 hours;

[0020] After 3 h, remove the round-bottom flask from the silicone oil bath. After the solution cools to room temperature, transfer 10 mL of the solution into four 50-mL centrifuge tubes. Add 10 mL of anhydrous ethanol to each tube and centrifuge at 12,000 rpm, 4°C, for 20 min.

[0021] S6. Place the final precipitate in an oven at 75°C until completely dry.

[0022] Another object of the present invention is to provide a metal organic framework for H2S detection, wherein the specific steps are as follows:

[0023] (a) 50 mg of sodium sulfide solid powder was weighed and dissolved in 10 mL of NaAc-HAc buffer (0.2 M pH = 4) to obtain a 5 mg / mL sodium sulfide solution as a source of hydrogen sulfide;

[0024] (b) Prepare 10 2 mL centrifuge tubes, add 150 μL H2O2 (100 mM), 250 μL Ce-MOF (0.05 mg / mL), 150 μL TMB (10 mM) and different volumes of NaAc-HAc buffer, and react for 30 min to ensure that the solution turns blue after sufficient reaction;

[0025] (c) After the reaction, 0.0, 6.0, 9.8, 19.7, 32.9, 41.3, 46.0, 55.2, 60.5, and 74.0 μL of sodium sulfide solution were added to 10 2 mL centrifuge tubes, respectively, to ensure that the total volume of the mixed solution in each centrifuge tube was 2 mL. After reacting for 2 minutes, the ultraviolet absorption of solution B was measured at 652 nm.

[0026] (d) The peak value of UV absorption of a series of solution B containing different concentrations of sodium sulfide decreases with the increase of sodium sulfide concentration, showing a continuous downward trend;

[0027] (e) Prepare 11 2 mL centrifuge tubes, add 150 μL H2O2 (100 mM), 250 μL Ce-MOF (0.05 mg / mL), 150 μL TMB (10 mM) and different volumes of NaAc-HAc buffer, and react for 30 min to ensure that the solution turns blue after sufficient reaction;

[0028] (f) After the reaction, 0.0, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 8.0, and 10.0 μL of sodium sulfide solution were added to each of the 11 2 mL centrifuge tubes, respectively, to ensure that the total volume of the mixed solution in each centrifuge tube was 2 mL. The fluorescence intensity of solution B was measured at an excitation wavelength of 325 nm.

[0029] Furthermore, the peak values ​​of the fluorescence intensities of a series of solutions B containing different concentrations of sodium sulfide increase with the increase of sodium sulfide concentration, showing a continuous upward trend.

[0030] The application of a sensor in H2S detection, the specific operation steps are as follows:

[0031] (1) Fifteen whiteleg shrimp were divided into three groups and placed in a -20°C refrigerator for frozen storage;

[0032] (2) 5 whiteleg shrimps were thawed every 2 days;

[0033] (3) Take 2.4 mL of NaAc-HAc buffer in a container, seal it with 5 thawed white shrimp with plastic wrap in a disposable white bottom tray, and place it in a 4°C refrigerator;

[0034] (4) On the fourth day, prepare three 2 mL centrifuge tubes and add 150 μL H2O2 (100 mM), 250 μL Ce-MOF (0.05 mg / mL), and 150 μL TMB (10 mM) to each tube. React for 30 min to ensure that the solution turns blue after sufficient reaction.

[0035] (5) Take out the samples on day 0, day 2, and day 4, take 1450 μL of 2.4 mL NaAc-HAc buffer on different days and react with the mixed solution at 25°C for 2 min, and observe the color change of the solution under sunlight and ultraviolet light respectively;

[0036] (6) The color of solution B under sunlight changed from dark blue to light blue from day 0 to day 4. The color of solution B under ultraviolet light changed from no obvious fluorescence to bright blue fluorescence from day 0 to day 4.

[0037] Furthermore, the sensor can perform colorimetric and fluorescence responses to H2S with different sensitivities.

[0038] Furthermore, the relationship between different concentrations of sodium sulfide in solution B and the corresponding dual-mode response of solution B for detecting hydrogen sulfide is specifically as follows: utilizing the functional relationship between different concentrations of sodium sulfide solution in solution B and the ultraviolet absorption peak value, the hydrogen sulfide concentration corresponding to the ultraviolet absorption peak value of hydrogen sulfide detected by solution B is obtained; utilizing the functional relationship between different concentrations of sodium sulfide solution in solution B and the fluorescence emission peak value, the hydrogen sulfide concentration corresponding to the fluorescence intensity value of hydrogen sulfide detected by solution B is obtained.

[0039] Technical principle of the present invention: The present invention adopts a solvothermal method, by mixing metal ions or clusters and organic ligands in a high-boiling point solvent, and reacting them under high temperature conditions to generate MOF. The solid polymer synthesized by this method is mainly composed of the metal ion ammonium cerium nitrate and the organic ligand 2-hydroxyterephthalic acid. The sensor is composed of Ce-MOF, 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 to form a colorimetric and fluorescent dual-response sensor. The sensor can accurately detect H2S based on ultraviolet absorption and fluorescence intensity, wherein the detection range of the sensor colorimetric response is 200-2300μM, and the detection range of the fluorescence response is 16-320μM, achieving more accurate detection of H2S and meeting the detection requirements of food freshness and safety.

[0040] Advantages and positive effects of the present invention:

[0041] 1. The present invention utilizes the fluorescence of 2-hydroxyterephthalic acid as a fluorescence detection signal for pH. Based on the fluorescence turn-on strategy, it shows obvious changes in fluorescence intensity and realizes visual detection.

[0042] 2. The present invention uses TMB as a colorimetric signal for detecting H2S, showing a significant color change and achieving visual detection;

[0043] 3. The sensor can detect H2S quantitatively and visually in real time / on-site, making the detection process portable, fast and low-cost;

[0044] 4. The present invention provides a method for preparing a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nano-metal organic framework materials, which has the ability to detect H2S gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1-7 They are scanning electron microscope images, transmission electron microscope images, infrared spectra, X-ray diffraction patterns, N2 adsorption-desorption isotherms, EDS patterns, and XPS pattern diagrams of Ce-MOF.

[0047] Figure 1 Schematic diagram of a scanning electron microscope image of the Ce-MOF material provided in Example 1.

[0048] Figure 2 Schematic diagram of the transmission electron microscope image of the Ce-MOF material provided in Example 1.

[0049] Figure 3 This is a schematic diagram of the infrared spectrum of the Ce-MOF material provided in Example 1.

[0050] Figure 4 Schematic diagram of the X-ray diffraction pattern of the Ce-MOF material provided in Example 1.

[0051] Figure 5 This is a schematic diagram of the N2 adsorption-desorption isotherm of the Ce-MOF material provided in Example 1.

[0052] Figure 6 This is a schematic diagram of the EDS spectrum of the Ce-MOF material provided in Example 1 (including Figure 6 a, 6b, 6c).

[0053] Figure 7 This is a schematic diagram of the XPS spectrum of the Ce-MOF material provided in Example 1.

[0054] Figure 8 Schematic diagram of the ultraviolet absorption spectrum and ultraviolet detection curve of the mixed solution after the reaction of different concentrations of sodium sulfide and the sensor provided in Example 2.

[0055] Figure 9 Schematic diagram of the fluorescence emission spectrum of the mixed solution after the reaction of different concentrations of sodium sulfide and the sensor provided in Example 3.

[0056] Figure 10 This is a schematic diagram of the fluorescence detection curve of the mixed solution after the sodium sulfide provided in Example 3 reacts with the sensor.

[0057] Figure 11This is a schematic diagram of the analysis of the selectivity and anti-interference of the dual-mode sensor for H2S provided in Example 4 (including Figure 11 a, 11b).

[0058] Figure 12 Schematic diagram of the color change of the solution when hydrogen sulfide is produced under sunlight and ultraviolet light in the real sample provided in Example 5 at the fresh, semi-fresh and corrupt stages (including Figure 12 a, 12b, 12c). DETAILED DESCRIPTION

[0059] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0060] Unless otherwise specified, the various raw materials used in the examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0061] Example 1

[0062] This embodiment first provides a MOF material, and its synthesis method includes the following steps: dissolving 164.5 mg of ammonium cerium nitrate and 109.3 mg of 2-hydroxyterephthalic acid in 15 mL of DMF and 45 mL of DMF, respectively, and performing ultrasonic treatment until completely dissolved.

[0063] 2-Hydroxyterephthalic acid was transferred to a 100 mL round-bottom flask, placed in silicone oil at 120° C., and stirred at 200 rpm using a magnetic stirrer.

[0064] 0.6 mL of acetic acid was added, and then the cerium ammonium nitrate solution was dripped into the round-bottom flask at a rate of one drop every 3 seconds.

[0065] After the addition was completed, the mixture was stirred for 6 min, the magnetic stirrer was turned off, and heating was maintained at 120°C for 3 h.

[0066] After 3 h, the round-bottom flask was extracted from the silicone oil bath. After the solution cooled to room temperature, the solution was equally transferred to four 50 mL centrifuge tubes, 10 mL of solution in each tube. 10 mL of anhydrous ethanol was then added to each tube, and the tubes were centrifuged at 12,000 rpm, 4°C, for 20 min.

[0067] The supernatant was removed, 10 mL of anhydrous ethanol was added, and the mixture was centrifuged. This step was repeated three times.

[0068] The final precipitate was placed in an oven at 75°C until completely dried to obtain Ce-MOF material.

[0069] Characterization of Ce-MOF, Figure 1-7 They are scanning electron microscope images, transmission electron microscope images, infrared spectra, X-ray diffraction patterns, N2 adsorption-desorption isotherms, EDS patterns, and XPS pattern diagrams of Ce-MOF.

[0070] Ce-MOF powder was added to distilled water at a concentration of 0.05 mg / mL and ultrasonically treated to obtain suspension A.

[0071] Example 2

[0072] This embodiment provides a method for detecting H2S based on colorimetric response, which specifically includes the following steps:

[0073] Suspension A needs to be shaken well before use.

[0074] 50 mg of sodium sulfide solid powder was weighed and dissolved in 10 mL of NaAc-HAc buffer (0.2 M pH = 4) to obtain a 5 mg / mL sodium sulfide solution as a source of hydrogen sulfide.

[0075] Prepare 10 2 mL centrifuge tubes, add 150 μL H2O2 (100 mM), 250 μL Ce-MOF (0.05 mg / mL), 150 μL TMB (10 mM) and different volumes of NaAc-HAc buffer, and react for 30 min to ensure that the solution turns blue after sufficient reaction.

[0076] After the reaction, 0.0, 6.0, 9.8, 19.7, 32.9, 41.3, 46.0, 55.2, 60.5, and 74.0 μL of sodium sulfide solution were added to the 10 2 mL centrifuge tubes, respectively, to ensure that the total volume of the mixed solution in each centrifuge tube was 2 mL. After reacting for 2 minutes, the ultraviolet absorption of solution B was measured at 652 nm.

[0077] The peak value of ultraviolet absorption of a series of solutions B containing different concentrations of sodium sulfide decreases with the increase of sodium sulfide concentration, showing a continuous downward trend.

[0078] Figure 8 This is a schematic diagram of the UV absorption spectrum and UV detection curve of the mixed solution after different concentrations of sodium sulfide react with the sensor.

[0079] Experiments have shown that the functional relationship between the UV absorption peak value and the H2S concentration is: Y = -0.3558X + 1.1913 (R 2 =0.9942), and the detection limit was 0.262 μM.

[0080] Example 3

[0081] This embodiment provides a method for detecting H2S based on fluorescence response, which specifically includes the following steps:

[0082] Suspension A needs to be shaken well before use.

[0083] 50 mg of sodium sulfide solid powder was weighed and dissolved in 10 mL of NaAc-HAc buffer (0.2 M pH = 4) to obtain a 5 mg / mL sodium sulfide solution as a source of hydrogen sulfide.

[0084] Prepare 11 2 mL centrifuge tubes, add 150 μL H2O2 (100 mM), 250 μL Ce-MOF (0.05 mg / mL), 150 μL TMB (10 mM) and different volumes of NaAc-HAc buffer, and react for 30 min to ensure that the solution turns blue after sufficient reaction.

[0085] After the reaction, 0.0, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 8.0, and 10.0 μL of sodium sulfide solution were added to the 11 2 mL centrifuge tubes, respectively, to ensure that the total volume of the mixed solution in each centrifuge tube was 2 mL. After reacting for 2 minutes, the fluorescence intensity of solution B was measured at an excitation wavelength of 325 nm.

[0086] The peak value of the fluorescence intensity of a series of solutions B containing different concentrations of sodium sulfide increases with the increase of sodium sulfide concentration, showing a continuous upward trend.

[0087] Experiments have shown that the functional relationship between the peak value of the fluorescence emission and the H2S concentration is: Y = 1.2768X - 1360.1600 (R 2 =0.9665), and the detection limit was 0.156 μM.

[0088] Figure 9 This is a schematic diagram of the fluorescence emission spectrum of the mixed solution after different concentrations of sodium sulfide react with the sensor.

[0089] Figure 10 A schematic diagram of the fluorescence detection curve of the mixed solution after different concentrations of sodium sulfide react with the sensor is shown.

[0090] Example 4

[0091] This embodiment provides a method for detecting the selectivity and anti-interference properties of a dual-mode sensor for H2S based on fluorescent nano-MOF, which specifically includes the following steps:

[0092] The same concentrations of selected interfering substances including glutamate, glutathione, cysteine, anions (NO 2- 、S2O4 2- 、SO3 2- 、NO 3- Br - 、SO4 2- 、CO3 2- ) and cations (Na + , Ca 2+ , K + 、Cu 2+ Mg 2+ NH4 + ).

[0093] Prepare several 2 mL centrifuge tubes, add 150 μL H2O2 (100 mM), 250 μL Ce-MOF (0.05 mg / mL), 150 μL TMB (10 mM) and an equal amount of NaAc-HAc buffer, and react for 30 min to ensure that the solution turns blue after sufficient reaction.

[0094] An equal amount of interfering substances was added, and the concentration of interfering substances in the solution for UV measurement was 192 μM, and the concentration of interfering substances in the solution for fluorescence measurement was 320 μM. After reacting for 2 minutes, the UV absorption spectrum and fluorescence spectrum of the reaction system were measured.

[0095] In a system containing interfering substances, sodium sulfide solution is added so that the concentration of sodium sulfide in the system remains consistent with the concentration of the system with sodium sulfide added but without interfering substances for measuring ultraviolet and fluorescence, respectively. After reacting for 2 minutes, the ultraviolet absorption spectrum and fluorescence spectrum of the reaction system are measured.

[0096] Figure 11 Schematic diagram of the analysis of the selectivity and anti-interference performance of the dual-mode sensor for H2S in this invention.

[0097] Experiments have shown that the presence of these interfering substances did not cause a significant change in the color of the reaction solution. In contrast, after the introduction of H2S, the UV absorption peak was significantly reduced and the fluorescence intensity was significantly enhanced. In the selectivity test, it is worth noting that interfering substances such as sulfite, thiosulfate and cysteine, which are very similar to H2S, have little effect on Ce-MOF. Their UV absorbance ratio and fluorescence intensity ratio are extremely less obvious than those of H2S. These results show that the Ce-MOF-based H2S detection method has excellent selectivity and anti-interference ability, that is, the established method has significant selectivity and can specifically distinguish and detect hydrogen sulfide despite the presence of potential interfering compounds.

[0098] Example 5

[0099] This embodiment provides a detection method for a dual-mode sensor for detecting H2S based on fluorescent nano-MOF, which specifically includes the following steps:

[0100] Fifteen whiteleg shrimps were divided into three groups and placed in a refrigerator at -20°C for frozen storage.

[0101] Five whiteleg shrimps were thawed every two days.

[0102] 2.4 mL of NaAc-HAc buffer was placed in a container, and the container was sealed with 5 thawed whiteleg shrimps in a disposable white bottom tray with plastic wrap, and placed in a 4°C refrigerator.

[0103] On the fourth day, prepare three 2 mL centrifuge tubes, add 150 μL H2O2 (100 mM), 250 μL Ce-MOF (0.05 mg / mL), and 150 uL TMB (10 mM) respectively, and react for 30 min to ensure that the solution turns blue after sufficient reaction.

[0104] The samples on day 0, day 2, and day 4 were taken out, and 1450 μL of 2.4 mL of NaAc-HAc buffer on different days was taken to react with the mixed solution for 2 min, and the color changes of the solution were observed under sunlight and ultraviolet light.

[0105] The color of the mixed solution under a sunlight light source changed from dark blue to light blue from the 0th day to the 4th day; the color of the mixed solution under an ultraviolet light source changed from no obvious fluorescence to bright blue fluorescence from the 0th day to the 4th day.

[0106] The sensor can respond to H2S with colorimetric and fluorescent signals of different sensitivities.

[0107] Figure 12 Schematic diagram of the solution color change when real samples are in the fresh, semi-fresh, and corrupt stages and produce hydrogen sulfide under sunlight and ultraviolet light.

[0108] In summary, the sensor of the present invention has a sensitive response to H2S, its ultraviolet absorption peak decreases with the increase of H2S, and its fluorescence emission peak increases with the increase of H2S, and the two are linearly related within a certain range.

[0109] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A method for preparing a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal organic framework materials, characterized in that: Specifically: The reaction solution is obtained by heating, mixing and stirring a solution of ammonium cerium nitrate and 2-hydroxyterephthalic acid; The reaction solution is washed, filtered, and dried to obtain a solid polymer A, namely Ce-MOF, wherein the detergent used in the washing is anhydrous ethanol; The solid polymer A was added to NaAc-HAc buffer at a concentration of 0.05 mg / mL, and solution A was obtained after ultrasonic oscillation. The peak data of the ultraviolet absorption and fluorescence emission spectra of solution A were detected and recorded. The peak of the ultraviolet absorption appeared at 325±5 nm, and the peak of the fluorescence emission appeared at 410±5 nm. Using 3,3',5,5'-tetramethylbenzidine (TMB) as a color development substrate, Ce-MOF, TMB, and H2O2 were mixed to obtain suspension B. The peak data of ultraviolet absorption of suspension B was detected and recorded. The peak of ultraviolet absorption appeared at 652 nm. Suspension B was mixed with sodium sulfide solutions of different concentrations to obtain solution B. The peak data of ultraviolet absorption and the peak data of fluorescence emission spectrum of solution B were detected and recorded. The peak of ultraviolet absorption appeared at 652 nm, and the peak of fluorescence emission appeared at 410±5 nm. The functional relationship between different concentrations of sodium sulfide solution in solution B and the value of ultraviolet absorption peak, as well as the functional relationship between different concentrations of sodium sulfide solution in solution B and the value of fluorescence emission peak, was used to obtain the relationship between different concentrations of sodium sulfide in solution B and the corresponding dual-mode response of solution B in detecting hydrogen sulfide; The solid polymer A synthesis method comprises the following steps: S1. Dissolve 164.5 mg of cerium ammonium nitrate and 109.3 mg of 2-hydroxyterephthalic acid in 15 mL of DMF and 45 mL of DMF, respectively, and sonicate until completely dissolved. S2. Transfer the 2-hydroxyterephthalic acid solution to a 100 mL round-bottom flask, place it in silicone oil at 120°C, and stir it with a magnetic stirrer at 200 rpm. S3. Add 0.6 mL of acetic acid, then drip the cerium ammonium nitrate solution into the round-bottom flask at a rate of one drop every 3 seconds. S4. After the addition is complete, stir for 6 min, turn off the magnetic stirrer, and heat at 120°C for 3 h. After 3 h, remove the round-bottom flask from the silicone oil bath. After the solution cools to room temperature, transfer 10 mL of the solution into four 50-mL centrifuge tubes. Add 10 mL of anhydrous ethanol to each tube and centrifuge at 12,000 rpm, 4°C, for 20 min. S6. Place the final precipitate in an oven at 75°C until completely dry.

2. The method for preparing a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal organic framework materials according to claim 1, characterized in that: The sensor is composed of H2O2, TMB, cerium ammonium nitrate and 2-hydroxyterephthalic acid. The structures of TMB and 2-hydroxyterephthalic acid are shown below: 。 3. The method for preparing a dual-mode sensor for detecting hydrogen sulfide based on fluorescent nanometal organic framework materials according to claim 1, characterized in that: The relationship between different concentrations of sodium sulfide in solution B and the corresponding dual-mode response of solution B for detecting hydrogen sulfide is specifically as follows: using the functional relationship between different concentrations of sodium sulfide solution in solution B and the ultraviolet absorption peak value, the hydrogen sulfide concentration corresponding to the different concentrations of sodium sulfide in solution B and the corresponding ultraviolet absorption peak value for detecting hydrogen sulfide in solution B is obtained; The functional relationship between different concentrations of sodium sulfide solution in the solution B and the fluorescence emission peak value is used to obtain the hydrogen sulfide concentration corresponding to the different concentrations of sodium sulfide in the solution B and the corresponding fluorescence intensity value of hydrogen sulfide detected by the solution B.

4. Application of a metal organic framework in H2S detection, characterized in that: The specific steps are: (a) Weigh 50 mg of sodium sulfide solid powder and dissolve it in 10 mL of NaAc-HAc buffer to obtain a 5 mg / mL sodium sulfide solution as the source of hydrogen sulfide; (b) Prepare 10 2 mL centrifuge tubes, add 150 μL of H2O2, 250 μL of Ce-MOF prepared as described in claim 1, 150 μL of TMB, and different volumes of NaAc-HAc buffer, respectively, and react for 30 min to ensure that the solution turns blue after sufficient reaction; (c) After the reaction, 0.0, 6.0, 9.8, 19.7, 32.9, 41.3, 46.0, 55.2, 60.5, and 74.0 μL of sodium sulfide solution were added to 10 2 mL centrifuge tubes, respectively, to ensure that the total volume of the mixed solution in each centrifuge tube was 2 mL. After the reaction for 2 min, the UV absorption of Solution B was measured at 652 nm. (d) The peak value of UV absorption of solution B containing different concentrations of sodium sulfide decreases with the increase of sodium sulfide concentration, showing a continuous downward trend; (e) Prepare 11 2 mL centrifuge tubes, add 150 μL of H2O2, 250 μL of Ce-MOF prepared as described in claim 1, 150 μL of TMB, and different volumes of NaAc-HAc buffer, respectively, and react for 30 min to ensure that the solution turns blue after sufficient reaction; (f) After the reaction, add 0.0, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0, 8.0, and 10.0 μL of sodium sulfide solution to each of the 11 2 mL centrifuge tubes, respectively, to ensure that the total volume of the mixed solution in each centrifuge tube is 2 mL. Measure the fluorescence intensity of solution B at an excitation wavelength of 325 nm.

5. The use according to claim 4, characterized in that The peak value of the fluorescence intensity of a series of solutions B containing different concentrations of sodium sulfide increases with the increase of sodium sulfide concentration, showing a continuous upward trend.

6. Application of the dual-mode sensor prepared by the preparation method according to claim 1 in H2S detection, characterized in that: The specific steps are: (1) Fifteen whiteleg shrimp were divided into three groups and placed in a -20°C refrigerator for freezing; (2) Take 5 whiteleg shrimps and thaw them every 2 days; (3) Take 2.4 mL of NaAc-HAc buffer solution in a container, seal it with 5 thawed white shrimp with plastic wrap in a disposable white bottom tray, and place it in a refrigerator at 4°C; (4) On the fourth day, prepare three 2 mL centrifuge tubes, add 150 μL H2O2, 250 μL Ce-MOF prepared as described in claim 1, and 150 μL TMB 10 mM to each tube, and react for 30 min to ensure that the solution turns blue after sufficient reaction; (5) Take out the samples on day 0, day 2, and day 4, take 1450 μL of 2.4 mL NaAc-HAc buffer from different days and react with the mixed solution at 25°C for 2 min, and observe the color change of the solution under sunlight and ultraviolet light respectively; (6) The color of solution B under sunlight changed from dark blue to light blue from day 0 to day 4; The color of solution B under ultraviolet light changed from no obvious fluorescence to bright blue fluorescence from day 0 to day 4.

7. The use according to claim 6, characterized in that The sensor responds to H2S colorimetrically and fluorescently with different sensitivities.

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