Iron porphyrin microporous organic polymer supported copper cluster composite material, synthesis method thereof and application thereof in detection of hydrogen sulfide and organophosphorus pesticides

Abstract

The application belongs to the technical field of chemical analysis and detection, and particularly relates to an iron porphyrin microporous organic polymer loaded copper cluster composite material, a synthesis method thereof and application thereof in detection of hydrogen sulfide and organophosphorus pesticides. Zinc nitrate hexahydrate, 2-methylimidazole, 1,4-diiodobenzene, 5,10,15,20-tetra(4-ethynylphenyl)porphyrin, ferric chloride hexahydrate, copper nitrate trihydrate, histidine, ascorbic acid (AA), methanol and N,N-dimethylformamide are used as raw materials to perform a reaction, and the iron porphyrin microporous organic polymer loaded copper cluster composite material is obtained. The application has the advantages of simple operation method, low cost, universality and easy scale production.

Description

Technical Field

[0001] This invention belongs to the field of chemical analysis and detection technology, specifically relating to an iron porphyrin microporous organic polymer supported copper cluster composite material, its synthesis method, and its application in the detection of hydrogen sulfide and organophosphorus pesticides. Background Technology

[0002] Hydrogen sulfide (H2S) gas is highly toxic and flammable; even low-concentration exposure can harm the respiratory and nervous systems. Meanwhile, the widespread use of organophosphorus pesticides (OPs) results in residues in soil and water, which can accumulate through the food chain and cause chronic poisoning. Accurate detection of these pollutants is crucial for pollution source tracing, risk assessment, and remediation decisions; however, existing detection methods still face many bottlenecks. Therefore, developing an accurate, stable, and highly sensitive method for detecting hydrogen sulfide and organophosphorus pesticide residues is of great significance in addressing these issues.

[0003] In recent years, numerous reports have been published on detection methods for hydrogen sulfide and organophosphorus pesticides. These methods include chemical titration, electrochemical analysis, chemiluminescence, gas detection, fluorescence, and colorimetry. However, conventional methods such as chemical titration suffer from long detection times, low accuracy, and complex processing. While fluorescence and electrochemical analysis offer shorter detection times, they still require an excitation light source or power supply, making them unsuitable for rapid in-situ detection outside the laboratory. In contrast, colorimetric sensors provide qualitative or quantitative information through color changes. Due to their minimal instrument requirements, ease of operation, and low cost, they have become the preferred detection method. Summary of the Invention

[0004] The purpose of this invention is to address the current state of hydrogen sulfide and organophosphorus pesticide detection by proposing a copper cluster composite material supported on iron porphyrin microporous organic polymer, its synthesis method, and its application in the detection of hydrogen sulfide and organophosphorus pesticides, thereby solving the aforementioned problems.

[0005] Therefore, a first aspect of the present invention provides a method for synthesizing a copper cluster composite material supported on a microporous organic polymer of iron porphyrin, the method comprising:

[0006] S1, Zn(NO3)2·6H2O solution was mixed with 2-methylimidazole solution and stirred to obtain ZIF-8;

[0007] S2, ZIF-8 and the catalyst were added to a mixture of triethylamine and the first DMF, and the mixture was sonicated under nitrogen. Then, a second DMF solution of 1,4-diiodobenzene and 5,10,15,20-tetra(4-ethynylphenyl)porphyrin was added, and the mixture was stirred under nitrogen to obtain ZIF-8@MOP. In this step, MOP was grown on the surface of ZIF-8 using 1,4-diiodobenzene and 5,10,15,20-tetra(4-ethynylphenyl)porphyrin.

[0008] S3, HCl solution was added to ZIF-8@MOP for etching, and MOP was obtained after stirring;

[0009] S4, MOP and FeCl3·6H2O were added to an organic solvent and reacted under nitrogen atmosphere to obtain Fe MOP;

[0010] S5, Fe MOP was added to histidine solution and ultrasonically mixed, then Cu(NO3)2·3H2O solution and AA solution were added and stirred to obtain Cu NCs@Fe MOP. In this step, a composite material was synthesized inside Fe MOP using Cu(NO3)2·3H2O, histidine, and AA.

[0011] As a preferred embodiment, in step S1 of the above-mentioned method for synthesizing copper cluster composite material supported by iron porphyrin microporous organic polymer, the solvent of Zn(NO3)2·6H2O solution is methanol.

[0012] As a preferred embodiment, in step S1 of the above-mentioned method for synthesizing copper cluster composite material supported by iron porphyrin microporous organic polymer, the solvent for the 2-methylimidazole solution is methanol.

[0013] According to a specific embodiment of the present invention, step S1 may be: dispersing Zn(NO3)2·6H2O in 5 mL of methanol, dispersing 2-methylimidazole in 5 mL of methanol, and then adding the methanol solution of 2-methylimidazole to the methanol solution of Zn(NO3)2·6H2O, and stirring at room temperature to obtain ZIF-8.

[0014] As a preferred embodiment, in step S1 of the above-mentioned method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material, the mass ratio of Zn(NO3)2·6H2O to 2-methylimidazolium is 145-152:810-830. This ratio ensures sufficient coordination between zinc ions and imidazolium ligands, forming a stable structure and providing a good support basis for subsequent loading of iron porphyrin and copper clusters.

[0015] As a preferred embodiment, in step S1 of the above-mentioned synthesis method of copper cluster composite material supported by iron porphyrin microporous organic polymer, the mixing and stirring time is 40-80 min, which helps the reactants to mix evenly, promotes the full progress of coordination reaction, avoids non-uniform nucleation caused by excessively high or low local concentration, and thus obtains particles with regular morphology.

[0016] As a preferred embodiment, in step S1 of the above-described method for synthesizing the copper cluster composite material supported by iron porphyrin microporous organic polymer, the mixing and stirring temperature is room temperature. The mixing and stirring process is preferably carried out at room temperature, eliminating the need for additional heating or cooling. This simplifies the operation and facilitates control of the crystal growth rate, resulting in materials with high specific surface area.

[0017] As a preferred embodiment, in step S2 of the above-mentioned method for synthesizing copper cluster composite materials supported by iron porphyrin microporous organic polymers, the catalyst is Pd(PPh3)2Cl2 and CuI, with a mass ratio of 0.5:0.1-0.14. This ratio can balance catalytic activity and control side reactions, ensuring effective polymerization of porphyrin monomers and forming a material with high stability and porous structure.

[0018] As a preferred embodiment, in step S2 of the above-mentioned method for synthesizing copper cluster composite material supported by iron porphyrin microporous organic polymer, the ultrasonic treatment time is 40-80 min, which helps to achieve sufficient contact, improve reaction uniformity, and promote the subsequent polymerization reaction.

[0019] As a preferred embodiment, in step S2 of the above-mentioned synthesis method of copper cluster composite material supported by iron porphyrin microporous organic polymer, the stirring reaction temperature is 88-92℃ and the time is 20-28h. This temperature control range can ensure that the polymerization reaction is fully and controllably carried out, while avoiding the decomposition of precursors or the generation of by-products caused by high temperature.

[0020] As a preferred embodiment, in step S2 of the above-mentioned method for synthesizing the copper cluster composite material supported by the iron porphyrin microporous organic polymer, the amounts of other components relative to 40 mg ZIF-8 are: 0.54-0.7 mg catalyst, 4-5.6 mL triethylamine, 0.3-0.5 mL first DMF, 8.4-10 mg 1,4-diiodobenzene, 9-11 mg 5,10,15,20-tetra(4-ethynylphenyl)porphyrin, and 0.6-1 mL DMF. This combination of components contributes to the formation of a structurally stable and porous ZIF-8@MOP composite material.

[0021] As a preferred embodiment, in step S3 of the above-mentioned method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material, the amount of HCl solution used is 2.4-4.8 mL relative to 15 mg ZIF-8@MOP, and the concentration of the HCl solution is 5.5-6.5 M. This amount of acid is sufficient to effectively dissolve zinc ions without excessively corroding the organic framework.

[0022] As a preferred embodiment, in step S3 of the above-mentioned synthesis method of iron porphyrin microporous organic polymer supported copper cluster composite material, MOP is obtained by stirring at room temperature for 40-80 min. Mild reaction conditions help maintain the integrity of the porous structure of MOP and avoid pore collapse or polymer degradation caused by high temperature or vigorous stirring.

[0023] As a preferred embodiment, in step S4 of the above-mentioned method for synthesizing copper cluster composite material supported by iron porphyrin microporous organic polymer, the organic solvent is methanol.

[0024] As a preferred embodiment, in step S4 of the above-mentioned method for synthesizing copper cluster composite materials supported by iron porphyrin microporous organic polymers, the stirring reaction temperature is 75-85℃, and the stirring reaction time is 20-28h. This temperature range is conducive to the coordination of iron ions with porphyrin to form a stable iron porphyrin structure, while avoiding solvent evaporation or polymer decomposition caused by high temperature.

[0025] As a preferred embodiment, in step S4 of the above-mentioned method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material, the amounts of other components relative to 5 mg MOP are: 6-10 mg FeCl3·6H2O and 1.5-3 mL organic solvent. This ratio ensures that the iron porphyrin is uniformly distributed within the MOP pores, forming a Fe MOP material with highly catalytically active sites.

[0026] As a preferred embodiment, in step S5 of the above-mentioned method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material, the concentrations of the histidine solution, Cu(NO3)2·3H2O solution, and AA solution are all 0.08-0.12M. This concentration range ensures that copper ions gradually aggregate to form stable copper clusters under mild reducing conditions, while avoiding excessive reduction or aggregation.

[0027] As a preferred embodiment, in step S5 of the above-mentioned method for synthesizing copper cluster composite material supported by iron porphyrin microporous organic polymer, the ultrasonic mixing time is 10-30 min, which helps to initially mix the reactants and promotes the pre-complexation of histidine with copper ions.

[0028] As a preferred embodiment, in step S5 of the above-mentioned synthesis method of copper cluster composite material supported by iron porphyrin microporous organic polymer, the stirring time is 20-28h to ensure that the copper clusters are uniformly nucleated and grown on the Fe MOP surface or in the pores.

[0029] As a preferred embodiment, in step S5 of the above-mentioned method for synthesizing the FeMOP microporous organic polymer-supported copper cluster composite material, the amounts of other components relative to 5 mg Fe MOP are: 8-12 mL histidine solution, 40-50 μL Cu(NO3)2·3H2O solution, and 450-550 μL AA solution. This combination helps to form CuNCs with uniform size and excellent catalytic performance, and achieves their efficient loading on the Fe MOP support, ultimately obtaining the FeMOP@CuNCs composite material.

[0030] A second aspect of the present invention provides a copper cluster composite material supported on an iron porphyrin microporous organic polymer, which is prepared by the above-described synthesis method.

[0031] A third aspect of the present invention provides the application of the above-described iron porphyrin microporous organic polymer-supported copper cluster composite material in the detection of hydrogen sulfide and organophosphorus pesticides. As a preferred embodiment, the application includes:

[0032] (1) Cu NCs@Fe MOP was modified on an indium tin oxide electrode;

[0033] (2) Prepare H2S of different concentrations as standard gas; add the electrode obtained in step (1) into H2S gas of different concentrations and let it stand, then take out the electrode and put it into a reaction system with 3,3',5,5'-tetramethylbenzidine (TMB) reagent and AA solution, and apply voltage for electrochemical activation, detect the color intensity of TMB, and establish a linear relationship between hydrogen sulfide concentration and color intensity based on the color intensity measured at a specific wavelength;

[0034] (3) Detect the gas to be tested, compare the detection results with the detection results of the standard gas, and obtain the concentration value of the gas to be tested;

[0035] (4) Prepare OPs of different concentrations as standard solutions; add the electrode obtained in step (1) into OPs solutions of different concentrations containing alkaline phosphatase (ALP) and Na3SPO3 and let it stand. Then take out the electrode and put it into the reaction system containing TMB reagent and AA solution, apply voltage for electrochemical activation, detect the TMB color intensity, and establish a linear relationship between OPs concentration and color intensity based on the color intensity measured at a specific wavelength.

[0036] (5) Test the solution to be tested, compare the test results with the test results of the standard solution, and obtain the concentration value of the solution to be tested.

[0037] As a preferred embodiment, the above-mentioned iron porphyrin microporous organic polymer-supported copper cluster composite material is used in the detection of hydrogen sulfide, with a detection linear range of 0.13~12.52μM. This composite material exhibits high sensitivity and selectivity for hydrogen sulfide, with a detection linear range of 0.13~12.52μM, making it suitable for the accurate quantification of low concentrations of hydrogen sulfide in environmental or biological samples.

[0038] As a preferred option, the aforementioned iron porphyrin microporous organic polymer-supported copper cluster composite material is used in the detection of organophosphorus pesticides, achieving a linear detection range of 0.1–1.1 μM. Based on an ALP biocatalysis and signal amplification strategy, this material exhibits a linear detection range of 0.1–1.1 μM for organophosphorus pesticides, meeting the analytical requirements for trace OPs residues in agricultural production and food safety. Different concentrations of organophosphorus pesticides (OPs) were used to construct standard curves; the degree to which they inhibited ALP activity was positively correlated with the OPs concentration, thus indirectly reflecting the OPs content in the sample.

[0039] As a preferred embodiment, in the application of the above-mentioned iron porphyrin microporous organic polymer-supported copper cluster composite material in the detection of hydrogen sulfide and organophosphorus pesticides, in step (2), the reaction system containing TMB reagent and AA solution has a concentration of 2-3 mM for TMB reagent and a concentration of 150-250 μM for AA. This concentration combination ensures that the colorimetric reaction is sensitive and stable, with obvious color changes, which is easy to identify by the naked eye or instruments. The reaction system is a sodium acetate buffer solution of KCl, or a pH 3.5 acetate-sodium acetate buffer solution; more preferably, the concentration of the sodium acetate buffer solution of KCl is 0.08-0.12 M, and the pH is 3.5. This buffer system can stabilize the reaction environment and optimize electron transfer and colorimetric efficiency.

[0040] As a preferred embodiment, the application of the above-mentioned iron porphyrin microporous organic polymer-supported copper cluster composite material in the detection of hydrogen sulfide and organophosphorus pesticides involves step (4) in OPs solutions containing different concentrations of ALP and Na3SPO3, where the concentration of ALP is 80-120 mU / mL and the concentration of Na3SPO3 is 2-4 mM. When constructing a cascaded catalytic signal amplification strategy, the working concentration of ALP is 80-120 mU / mL, which can effectively catalyze the generation of hydrogen sulfide from sodium thiophosphate, simulating the signal transduction process in vivo; as a precursor of hydrogen sulfide, the concentration of sodium thiophosphate is 2-4 mM, which can ensure a stable hydrogen sulfide generation rate and provide a reliable signal source for subsequent sensing detection.

[0041] As a preferred embodiment, in the application of the above-mentioned iron porphyrin microporous organic polymer-supported copper cluster composite material in the detection of hydrogen sulfide and organophosphorus pesticides, in step (4) the reaction system containing TMB reagent and AA solution, the concentration of TMB reagent is 2-3 mM, the concentration of AA is 150-250 μM, and the reaction system is KCl sodium acetate buffer; more preferably, the concentration of KCl sodium acetate buffer is 0.08-0.12 M, and the pH is 3.5.

[0042] As a preferred embodiment, in the application of the above-mentioned iron porphyrin microporous organic polymer-supported copper cluster composite material in the detection of hydrogen sulfide and organophosphorus pesticides, in step (2), the specific wavelength is 644-660 nm, which is determined by conventional techniques in the art, with 652 nm being the most preferred. This wavelength is the maximum absorption peak of the TMB oxidation product, enabling highly sensitive detection of the reaction process.

[0043] As a preferred embodiment, in the application of the above-mentioned iron porphyrin microporous organic polymer-supported copper cluster composite material in the detection of hydrogen sulfide and organophosphorus pesticides, in step (4), the specific wavelength is 644-660 nm, which is determined by conventional techniques in the art, with 652 nm being the most preferred. This wavelength is the maximum absorption peak of the TMB oxidation product, enabling highly sensitive detection of the reaction process.

[0044] The relevant principles of this invention include:

[0045] Using ascorbic acid (AA) and 3,3',5,5'-tetramethylbenzidine (TMB) as substrates, hydrogen peroxide (H2O2) is generated by oxidizing AA. Fe MOP catalyzes the oxidation of TMB by H2O2, resulting in a colorimetric reaction. Electrochemical activation leads to a more pronounced colorimetric reaction. H2S can specifically coordinate with the copper and iron active sites in the complex, achieving signal transduction by regulating catalytic activity. Furthermore, by combining the biotransformation process of sodium thiophosphate (Na3SPO3) to H2S catalyzed by alkaline phosphatase (ALP), and leveraging the inhibitory effect of OPs on ALP activity, an ultrasensitive colorimetric sensing platform based on a cascade catalytic signal amplification strategy was successfully constructed. This platform enables the quantitative detection of H2S and can be extended to the efficient analysis of OPs.

[0046] The CuNCs@Fe MOP material prepared by the above method is synthesized from CuNCs and Fe MOP. CuNCs is a nanozyme with AA oxidase-like activity, where Cu acts as the catalytic active site, oxidizing AA to dehydroascorbic acid (DHAA) and producing H2O2. Fe MOP, like peroxidase, has a similar prosthetic group structure and exhibits high catalytic activity for H2O2, catalyzing the H2O2 produced by CuNCs. Electrochemical activation enhances both the AA oxidase-like activity of CuNCs and the peroxidase-like activity of Fe MOP. The combination of CuNCs and Fe MOP not only improves nanozyme activity, achieving a multi-enzyme cascade catalytic effect, but also enhances detection stability, enabling effective detection of hydrogen sulfide and organophosphorus pesticides.

[0047] H2S can specifically coordinate with the copper and iron active sites in the complex, thereby regulating catalytic activity and achieving signal transduction, which allows for the quantitative determination of H2S concentration. Furthermore, by combining the biotransformation process of Na3SPO3 to H2S catalyzed by ALP, and leveraging the inhibitory effect of OPs on ALP activity, the precise detection of OPs was successfully achieved.

[0048] Since the synthesized Cu NCs@Fe MOP has a large number of copper and iron metal nodes, the active sites of the Cu NCs@Fe MOP material are blocked by H2S coordination with the copper and iron metal nodes, resulting in a decrease in the catalytic activity of the nanozyme.

[0049] AA serves as a catalytic substrate for Cu NCs, which can be catalyzed into DHAA and H2O2, thus connecting the entire detection system in series. TMB reagent acts as a sensor signal amplifier, converting the concentration signals of H2S and OPs into colorimetric signals that are easy to observe.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] 1. The synthesis process of CuNCs@Fe MOP is simple, time-efficient, and uses inexpensive and readily available raw materials. Applied to the field of colorimetric sensing, the proximity effect of the two nanozymes determines its outstanding catalytic activity, and the enzyme-like activity is enhanced after electrochemical activation, enabling efficient detection of H2S and OPs. In summary, the CuNCs@Fe MOP of this invention is a low-cost, convenient, and sensitive probe for the detection of H2S and OPs, with broad application prospects in the field of colorimetric sensing.

[0052] 2. The present invention has a simple operation method, low cost, universality, and is easy to scale up for production. Furthermore, the electrochemically activated Cu NCs@Fe MOP cascade system is the novel and unique feature of this invention.

[0053] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0054] Figure 1 This is a transmission electron microscope (TEM) image of Cu NCs@Fe MOP in Example 1;

[0055] Figure 2 The UV-Vis absorption spectra of TMB+AA+Cu NCs@Fe MOP and TMB+AA+Cu NCs@Fe MOP+H2S in an acetate-sodium acetate buffer solution at pH=3.5 in Example 1 are shown.

[0056] Figure 3 Example 2 shows the detection of H2S by Cu NCs@Fe MOP colorimetric method, where a is the UV-Vis absorption spectrum at different H2S concentrations, and b is the linear relationship between H2S concentration and absorbance.

[0057] Figure 4 Example 2 shows the detection of OPs using the Cu NCs@Fe MOP colorimetric method, where a is the UV-Vis absorption spectrum at different OPs concentrations, and b is the linear relationship between OPs concentration and absorbance. Detailed Implementation

[0058] The following description provides numerous specific details to offer a more thorough understanding of the technical solutions provided by this invention. However, it will be apparent to those skilled in the art that the technical solutions provided by this invention can be implemented without one or more of these details.

[0059] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0060] In the embodiments and comparative examples of this invention, the raw materials are commercially available.

[0061] Example 1

[0062] The preparation process of Cu NCs@Fe MOP is as follows:

[0063] S1, Synthesis of ZIF-8: 148.4 mg of Zn(NO3)2·6H2O was dispersed in 5 mL of methanol, 819.5 mg of 2-methylimidazole was dispersed in 5 mL of methanol, and then the methanol solution of 2-methylimidazole was added to the methanol solution of Zn(NO3)2·6H2O. The mixture was stirred at room temperature for 1 h to obtain ZIF-8.

[0064] S2, 40 mg ZIF-8, 0.5 mg Pd(PPh3)2Cl2 and 0.12 mg CuI were added to a mixture of 4.8 mL triethylamine and 0.4 mL DMF. The mixture was sonicated for 1 h under nitrogen atmosphere, followed by the addition of 0.8 mL DMF solution of 9.2 mg 1,4-diiodobenzene and 10 mg 5,10,15,20-tetra(4-ethynylphenyl)porphyrin. The reaction mixture was then stirred at 90 °C under nitrogen atmosphere for 24 h to obtain ZIF@MOP.

[0065] S3, add 3.6 mL of 6M HCl solution to 15 mg ZIF-8@MOP and stir at room temperature for 1 h to obtain MOP;

[0066] S4, 5 mg MOP and 8 mg FeCl3·6H2O were added to 2.2 mL of methanol, and the reaction mixture was stirred at 80 °C under nitrogen for 24 h to obtain Fe MOP;

[0067] S5, 5 mg Fe MOP was added to 10 mL of 0.10 M histidine solution and sonicated for 20 min. Then, 45 μL of 0.10 M Cu(NO3)2·3H2O solution and 500 μL of 100 mM AA solution were added and stirred for 24 h to obtain Cu NCs@Fe MOP.

[0068] Transmission electron microscopy (TEM) was used to observe Cu NCs@Fe MOP, and the results are shown in the attached figure. Figure 1 As shown, smaller Cu NCs particles can be observed confined within the Fe MOP.

[0069] Detection and analysis using ultraviolet-visible absorption spectroscopy instruments, such as... Figure 2 (The horizontal axis represents wavelength, and the vertical axis represents absorbance.) As shown, a strong colorimetric signal is generated in the Cu NCs@Fe MOP-TMB-AA system; after adding H2S, S... 2- The binding of copper and iron in Cu NCs@Fe MOP affects the active sites, leading to a weakening of the catalytic effect and quenching of the colorimetric signal.

[0070] Example 2

[0071] A method for colorimetric detection of H2S and OPs concentrations using Cu NCs@Fe MOP includes:

[0072] S1. First, prepare H2S solutions of different concentrations, and then add 100 μL of each solution to different sealed centrifuge tubes. Next, insert the ITO electrode coated with 5 μL of Cu NCs@Fe MOP into the sealed centrifuge tubes. Then, inject 200 μL of 1M dilute H2SO4 into the sealed centrifuge tubes using a syringe. After incubation for 10 min, remove the ITO electrode.

[0073] S2, then immerse it in a sodium acetate buffer solution containing 0.1M KCl with AA (200 μM) and TMB (2.5 mM). Apply a voltage of -0.3 V to the reaction system for 5 min, then record the absorbance at 652 nm; the detection results are as follows. Figure 3 As shown in Figure a (where the horizontal axis represents wavelength and the vertical axis represents absorbance), the colorimetric signal intensity decreases as the H2S concentration increases, indicating a good linear relationship between H2S concentration and colorimetric signal intensity. Figure 3 (See Figure b in the diagram), the linear equation is y = 0.0027 + 0.0663x (R²). 2 =0.993), x is the H2S concentration, the linear range is 0.13~12.52μM, and the detection limit is 0.07μM. This indicates that CuNCs@Fe MOP has a low detection limit and a wide detection range for the colorimetric signal intensity of H2S, and has good application value.

[0074] S3. Detect the gas to be tested, compare the detection result with the detection result of the standard gas, and obtain the concentration value of the gas to be tested.

[0075] S4. Add OPs solutions of different concentrations to sealed centrifuge tubes, then add ALP solution (100 mU / mL), add Na3SPO3 (3 mM), and then insert the ITO electrode coated with 5 μL Cu NCs@Fe MOP into the centrifuge tubes and incubate at 40℃ for 100 min.

[0076] S5. Then, the ITO electrode was immersed in a 0.1M KCl sodium acetate buffer solution (0.1M, pH 3.5), and AA (200μM) and TMB (2.5mM) were added. A voltage was then applied to the reaction system for 5 min. The absorbance at 652 nm was then recorded. The detection results are as follows: Figure 4 As shown in Figure a (where the horizontal axis represents wavelength and the vertical axis represents absorbance), the colorimetric signal intensity decreases as the OPs concentration increases, indicating a good linear relationship between OPs concentration and colorimetric signal intensity. Figure 4(Figure b in the diagram), the linear equation is y = 0.032 + 0.693x (R²). 2 =0.991), x is the concentration of OPs, the linear range is 0.1~1.1μM, and the detection limit is 0.06μM. This indicates that CuNCs@Fe MOP has a low detection limit and a wide detection range for the colorimetric signal intensity of OPs, and has good application value.

[0077] S6. Test the solution to be tested, compare the test results with the test results of the standard solution, and obtain the concentration value of the solution to be tested.

[0078] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for synthesizing a copper cluster composite material supported on iron porphyrin microporous organic polymer, characterized in that, The synthesis method includes: S1, Zn(NO3)2·6H2O solution was mixed with 2-methylimidazole solution and stirred to obtain ZIF-8; S2, ZIF-8 and the catalyst were added to a mixture of triethylamine and the first DMF, and the mixture was sonicated under nitrogen. Then, a second DMF solution of 1,4-diiodobenzene and 5,10,15,20-tetra(4-ethynylphenyl)porphyrin was added, and the mixture was stirred under nitrogen to obtain ZIF-8@MOP. S3, add HCl solution to ZIF-8@MOP and stir to obtain MOP; S4, MOP and FeCl3·6H2O were added to an organic solvent and reacted under nitrogen atmosphere to obtain Fe MOP; S5, Fe MOP was added to histidine solution and ultrasonically mixed, then Cu(NO3)2·3H2O solution and AA solution were added and stirred to obtain Cu NCs@Fe MOP.

2. The method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material according to claim 1, characterized in that, Satisfy at least one of the following characteristics: In step S1, the solvent for the Zn(NO3)2·6H2O solution is methanol; In step S1, the solvent for the 2-methylimidazole solution is methanol; In step S1, the mass ratio of Zn(NO3)2·6H2O to 2-methylimidazole is 145-152:810-830; In step S1, the mixing and stirring time is 40-80 minutes; In step S1, the mixing temperature is room temperature.

3. The method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material according to claim 1, characterized in that, Satisfy at least one of the following characteristics: In step S2, the catalysts are Pd(PPh3)2Cl2 and CuI, with a mass ratio of 0.5:0.1-0.

14. In step S2, the ultrasonic treatment time is 40-80 minutes; In step S2, the temperature of the stirring reaction is 88-92℃, and the time is 20-28h; In step S2, relative to 40 mg ZIF-8, the amounts of other components are as follows: 0.54-0.7 mg catalyst, 4-5.6 mL triethylamine, 0.3-0.5 mL first DMF, 8.4-10 mg 1,4-diiodobenzene, 9-11 mg 5,10,15,20-tetra(4-ethynylphenyl)porphyrin, and 0.6-1 mL DMF.

4. The method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material according to claim 1, characterized in that, Satisfy at least one of the following characteristics: In step S3, the volume of HCl solution used is 2.4-4.8 mL relative to 15 mg ZIF-8@MOP; In step S3, the concentration of the HCl solution is 5.5-6.5 M; In step S3, MOP is obtained by stirring at room temperature; In step S3, the stirring time is 40-80 minutes.

5. The method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material according to claim 1, characterized in that, Satisfy at least one of the following characteristics: In step S4, the organic solvent is methanol; In step S4, the temperature of the stirring reaction is 75-85℃, and the stirring reaction time is 20-28h; In step S4, relative to 5 mg MOP, the amounts of other components are: 6-10 mg FeCl3·6H2O and 1.5-3 mL organic solvent.

6. The method for synthesizing the iron porphyrin microporous organic polymer-supported copper cluster composite material according to claim 1, characterized in that, Satisfy at least one of the following characteristics: In step S5, the concentration of the histidine solution is 0.08-0.12M; In step S5, the concentration of the Cu(NO3)2·3H2O solution is 0.08-0.12M; In step S5, the concentration of the AA solution is 0.08-0.12M; In step S5, the ultrasonic mixing time is 10-30 min; In step S5, the stirring time is 20-28 hours; In step S5, relative to 5 mg Fe MOP, the amounts of other components are: 8-12 mL histidine solution, 40-50 μL Cu(NO3)2·3H2O solution, and 450-550 μL AA solution.

7. A copper cluster-supported composite material of iron porphyrin microporous organic polymer, characterized in that, It is prepared by the synthesis method of any one of claims 1-6.

8. The application of the iron porphyrin microporous organic polymer supported copper cluster composite material according to claim 7 in the detection of hydrogen sulfide and organophosphorus pesticides.

9. The application of the iron porphyrin microporous organic polymer-supported copper cluster composite material according to claim 8 in the detection of hydrogen sulfide and organophosphorus pesticides, characterized in that, The applications include: (1) Cu NCs@Fe MOP was modified on an indium tin oxide electrode; (2) Prepare H2S of different concentrations as standard gas; add the electrode obtained in step (1) into H2S gas of different concentrations and let it stand, then take out the electrode and put it into the reaction system with TMB reagent and AA solution, apply voltage for electrochemical activation, detect the color intensity of TMB, and establish a linear relationship between hydrogen sulfide concentration and color intensity based on the color intensity measured at a specific wavelength. (3) Detect the gas to be tested, compare the detection results with the detection results of the standard gas, and obtain the concentration value of the gas to be tested; (4) Prepare OPs of different concentrations as standard solutions; add the electrode obtained in step (1) into OPs solutions of different concentrations containing ALP and Na3SPO3 and let it stand, then take out the electrode and put it into the reaction system containing TMB reagent and AA solution, apply voltage for electrochemical activation, detect the color intensity of TMB, and establish a linear relationship between OPs concentration and color intensity based on the color intensity measured at a specific wavelength; (5) Test the solution to be tested, compare the test results with the test results of the standard solution, and obtain the concentration value of the solution to be tested.

10. The application of the iron porphyrin microporous organic polymer-supported copper cluster composite material according to claim 8 in the detection of hydrogen sulfide and organophosphorus pesticides, characterized in that, Satisfy at least one of the following characteristics: In the detection of hydrogen sulfide, the linear range of detection is 0.13~12.52μM; Its application in the detection of organophosphorus pesticides shows a linear detection range of 0.1–1.1 μM. In step (2), the reaction system containing TMB reagent and AA solution has a concentration of 2-3 mM and a concentration of AA of 150-250 μM. The reaction system is a sodium acetate buffer solution of KCl. Optionally, the concentration of the sodium acetate buffer solution of KCl is 0.08-0.12 M and the pH is 3.

5. Step (4) In OPs solutions containing different concentrations of ALP and Na3SPO3, the concentration of ALP is 80-120 mU / mL and the concentration of Na3SPO3 is 2-4 mM. In step (4), the reaction system containing TMB reagent and AA solution has a concentration of 2-3 mM and a concentration of AA of 150-250 μM. The reaction system is a sodium acetate buffer solution of KCl. Optionally, the concentration of the sodium acetate buffer solution of KCl is 0.08-0.12 M and the pH is 3.

5. In step (2), the specific wavelength is 644-660nm; In step (4), the specific wavelength is 644-660nm.

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