Terbium-doped benzene polycarboxylic acid-metformin hof material and its application in detecting explosive precursor sodium hypochlorite

Abstract

This application discloses a terbium-doped benzenepolycarboxylic acid-bismethylguanidine (HOF) material and its application in the detection of the explosive precursor sodium hypochlorite, belonging to the field of fluorescent probes and fluorescent detection technology. This terbium-doped benzenepolycarboxylic acid-bismethylguanidine (HOF) material consists of an HOF matrix and rare earth metal ions (Tb). 3+ The HOF matrix is ​​composed of a coordination complex and is constructed from a benzene polycarboxylic acid compound and metformin hydrochloride through intermolecular hydrogen bonding self-assembly. This material can pass through Tb... 3+ Characteristic fluorescence emission at 545nm ( 5 D4→ 7 The F5 transition exhibits a highly selective fluorescence quenching response to sodium hypochlorite (NaClO), with a low detection limit and a wide linear range, enabling rapid and highly sensitive detection of low concentrations of NaClO. This is of great significance for blocking NaClO-based explosive synthesis.

Description

Technical Field

[0001] This application belongs to the field of fluorescent probe and fluorescent detection technology, specifically relating to a terbium-doped benzene polycarboxylic acid-bismethyl guanidine HOF material (Tb 3+ Doped HOF materials and their preparation methods, further relating to Tb 3+ Application of HOF-doped materials in the detection of sodium hypochlorite, an explosive precursor. Background Technology

[0002] Sodium hypochlorite (NaClO) solution releases hypochlorite ions (ClO) under alkaline conditions. - ClO is a common oxidizing agent used in industrial bleaching and disinfection. Recent studies have shown that ClO... - In acidic or near-neutral environments, it can undergo synergistic oxidation with hydrogen peroxide (H2O2), converting acetone (CH3CHOCH3) into triacetone triperoxide (TATP, C9H2O). 18 TATP (total oxidized hydrogen peroxide) is an organic peroxide explosive characterized by its extreme sensitivity. It is easily detonated by slight friction, high temperatures (97-160℃, spontaneous combustion), or in confined conditions, with a detonation velocity reaching 5300 m / s (equivalent to 83% of TNT). Notably, because TATP does not contain nitrogen, it is difficult to detect by traditional explosive detectors; therefore, monitoring its raw material processes is essential. However, the synthesis route of TATP requires only three commercially available chemicals: acetone, H₂O₂, and sodium hypochlorite. These raw materials are common industrial and civilian chemicals, with sodium hypochlorite being widely used as a civilian chemical, such as in disinfectants and bleaching agents. Therefore, sodium hypochlorite, as a key oxidation-cyclization precursor in the preparation of TATP, requires significant on-site, real-time, and highly sensitive monitoring.

[0003] Traditional methods for detecting sodium hypochlorite include iodometric titration, spectrophotometry / spectroscopy, electrochemical methods, and chromatography. However, these methods suffer from problems such as delayed results and insufficient resistance to interference, and are difficult to implement in-situ real-time detection of sodium hypochlorite. In recent years, fluorescent probe detection technology has developed rapidly. Compared with traditional detection methods, it has the advantages of high sensitivity and low detection limit, making it very suitable for the detection of low concentrations of sodium hypochlorite. Furthermore, it offers fast response speed and simple operation, making it ideal for in-situ real-time detection.

[0004] However, current fluorescent probes for sodium hypochlorite detection still suffer from insufficient anti-interference capabilities, and their accuracy and selectivity need improvement. Therefore, there is an urgent need to develop a fluorescent probe material for sodium hypochlorite to meet the requirements for rapid on-site screening and quantitative tracking of sodium hypochlorite, a key precursor of TATP, and to achieve rapid identification of widely circulated civilian chemical sodium hypochlorite solutions (such as "84" disinfectant). Summary of the Invention

[0005] In view of this, the primary objective of this application is to provide a terbium-doped benzene polycarboxylic acid-bismethylguanidine HOF material, which can be used as a high-performance fluorescent probe to achieve ultra-high sensitivity and high selectivity detection of the explosive precursor NaClO.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] One aspect of this application discloses a terbium-doped benzene polycarboxylic acid-bismethyl guanidine (HOF) material, which is composed of an HOF matrix and rare earth metal ions (Tb). 3+ The HOF matrix is ​​composed of a coordination complex and is constructed by intermolecular hydrogen bonding self-assembly of a benzene polycarboxylic acid compound and metformin hydrochloride.

[0008] Another aspect of this application discloses a method for preparing the terbium-doped benzene polycarboxylic acid-bismethyl guanidine (HOF) material described in this application, comprising the following steps:

[0009] The HOF matrix was obtained by hydrogen bonding self-assembly of a benzene polycarboxylic acid compound and metformin hydrochloride;

[0010] The HOF matrix was mixed with an organic solution of Tb salt to prepare terbium-doped benzene polycarboxylic acid-bismethylguanidine HOF material.

[0011] Another aspect of this application discloses the application of terbium-doped benzenepolycarboxylic acid-bismethylguanidine (HOF) materials as described in this application or terbium-doped benzenepolycarboxylic acid-bismethylguanidine (HOF) materials prepared using the methods described in this application as fluorescent probes in the detection of hypochlorite.

[0012] Another aspect of this application discloses a kit for detecting the explosive precursor sodium hypochlorite, the kit containing the terbium-doped benzene polycarboxylic acid-metformin HOF material described in this application or the terbium-doped benzene polycarboxylic acid-metformin HOF material prepared using the method described in this application.

[0013] Another aspect of this application discloses a method for detecting the explosive precursor sodium hypochlorite, comprising the following steps:

[0014] Tb 3+ Aqueous dispersions were prepared by doping HOF materials;

[0015] The sample to be tested was added to the aqueous dispersion and mixed thoroughly. The fluorescence emission intensity at 545 nm was then detected under 330 nm excitation light.

[0016] The content of NaClO in the sample to be tested was obtained based on the linear relationship equation between NaClO solutions of different concentrations and fluorescence intensity.

[0017] The beneficial effects of this application are:

[0018] This application discloses a terbium-doped benzene polycarboxylic acid-bismethyl guanidine HOF material (Tb 3+ (HOF-doped material), this Tb 3+ The preparation process of doped HOF materials is simple, the reaction conditions are mild, no high temperature and high pressure are required, and it is easy to prepare on a large scale. In this application, Tb... 3+ HOF materials are constructed by using benzene polycarboxylic acid compounds and metformin hydrochloride as mixed ligands. The amino and guanidine groups in the metformin hydrochloride molecule may provide effective recognition sites, thereby achieving specific recognition of hypochlorite.

[0019] The Tb provided in this application 3+ Doped HOF materials can pass Tb 3+ Characteristic fluorescence emission at 545nm ( 5 D4→ 7 The F5 transition produces a highly selective fluorescence quenching response to sodium hypochlorite (NaClO), with a low detection limit, a wide linear range, and high sensitivity. It can achieve rapid and highly sensitive detection of low concentrations of NaClO in real time and on-site, with a detection limit reaching the nanogram level (as low as 104 ng / mL), thus blocking the synthesis of explosives using sodium hypochlorite as a raw material. Attached Figure Description

[0020] Figure 1 This is a scanning electron microscope (SEM) image of the Tb@PMA-MET material in Example 1 of this application.

[0021] Figure 2 This is the energy dispersive spectroscopy (EDS) analysis diagram of the Tb@PMA-MET material in Example 1 of this application.

[0022] Figure 3 The UV-Vis absorption spectrum of the Tb@PMA-MET material in Example 1 of this application is shown below. Figure 3 (A) and fluorescence excitation / emission spectra ( Figure 3 (B)

[0023] Figure 4 The infrared spectra of the HOF matrix and Tb@PMA-MET material in Example 1 of this application are shown below. Figure 4 (A) and X-ray diffraction pattern ( Figure 4 (B)

[0024] Figure 5 The fluorescence response curves of Tb@PMA-MET material in Application Example 1 of this application at different concentrations of NaClO (100 ng / mL → 1 mg / mL) are shown below. Figure 5(A) and the linear relationship between fluorescence intensity at 545 nm and the logarithm of NaClO concentration (Plot A) Figure 5 (B)

[0025] Figure 6 The selectivity of Tb@PMA-MET material for NaClO in Application Example 1 of this application ( Figure 6 (A) and anti-interference ( Figure 6 Test results (B)

[0026] Figure 7 The fluorescence response curves of Tb@PMA-MET material in Application Example 2 of this application at different concentrations of NaClO (100 ng / mL → 1 mg / mL) are shown below. Figure 7 (A) and the linear relationship between fluorescence intensity at 545 nm and the logarithm of NaClO concentration (Plot A) Figure 7 (B)

[0027] Figure 8 The fluorescence response curves of Tb@PMA-MET material in Application Example 3 of this application at different concentrations of NaClO (500 ng / mL → 1 mg / mL) are shown below. Figure 8 (A) and the linear relationship between fluorescence intensity at 545 nm and the logarithm of NaClO concentration (Plot A) Figure 8 (B) Detailed Implementation

[0028] The embodiments of this application will be clearly and completely described below. The technical solutions in the embodiments described below are exemplary and only possible technical implementations of this application, not all possible implementations. Those skilled in the art can combine the embodiments of this application to obtain other embodiments without creative effort, and these embodiments are also within the protection scope of this application.

[0029] The first aspect of this application discloses a terbium-doped benzene polycarboxylic acid-bismethyl guanidine HOF material (Tb 3+ HOF-doped materials, which consist of an HOF matrix and rare earth metal ions Tb 3+ The HOF matrix is ​​composed of a coordination complex and is constructed by intermolecular hydrogen bonding self-assembly of a benzene polycarboxylic acid compound and metformin hydrochloride.

[0030] As described in this application, the benzene polycarboxylic acid compound is a class of organic compounds with two or more carboxyl groups (-COOH) attached to a benzene ring. As an example, the benzene polycarboxylic acid compound in this application may be at least one of isophthalic acid, phthalic acid, terephthalic acid, 1,2,4-triphenylcarboxylic acid, pyromellitic acid, and pyromellitic tetracarboxylic acid, but is not limited thereto.

[0031] Benzene polycarboxylic acid compounds and metformin hydrochloride self-assemble via intermolecular hydrogen bonds to form a hydrogen-bonded organic framework (HOF). This HOF matrix is ​​then bonded to Tb. 3+ Coordination complexation to form Tb 3+ Doped HOF material. This Tb 3+ In HOF-doped materials, the inherent amino and guanidinyl functional groups in metformin hydrochloride may provide effective recognition sites, thereby achieving specific recognition of hypochlorite ions. Furthermore, this material generates Tb at 545 nm under 330 nm light excitation. 3+ Characteristic fluorescence emission ( 5 D4→ 7 (F5), and this emission can be specifically quenched by sodium hypochlorite, achieving ultra-high sensitivity detection of sodium hypochlorite.

[0032] The second aspect of this application discloses a method for preparing the Tb described in the first aspect of this application. 3+ The method for doping HOF materials mainly includes the following steps:

[0033] S1. Preparation of HOF matrix.

[0034] In this step, the benzene polycarboxylic acid compound and metformin hydrochloride are dissolved in methanol and fully dispersed to form a homogeneous mixture. The mixture is then allowed to stand at room temperature to evaporate, and the benzene polycarboxylic acid compound and metformin hydrochloride undergo intermolecular hydrogen bond self-assembly to form the HOF matrix.

[0035] There are no particular limitations on the dispersion method of benzene polycarboxylic acid compounds and metformin hydrochloride in methanol. Any technical method in the art can be used to achieve this. In some specific examples of this application, ultrasonic dispersion is used.

[0036] In some specific examples, the mass ratio of the benzene polycarboxylic acid compound to metformin hydrochloride is (1.8~2.2):1; 20~40 mL of methanol is used per 100 mg of metformin hydrochloride. It is understood that by adjusting or optimizing a suitable ratio, the microstructure of the material can be controlled, thereby optimizing the material properties. Therefore, those skilled in the art can adjust and obtain a suitable ratio through experimental methods or experience, and are not limited to the examples provided in this application.

[0037] Understandably, the evaporation time needs to be long enough to ensure complete self-assembly. As an example, the preferred evaporation time at room temperature is 24-96 hours.

[0038] Furthermore, after evaporation, post-treatment steps are included, specifically centrifugation, washing, and drying. These steps are conventional procedures in the art and therefore are not particularly limited. In the example of this application, washing is performed using ethanol, and drying is carried out at 60-80°C to ensure the material is completely dry.

[0039] S2, Tb doping in HOF matrix 3+ .

[0040] In this step, Tb is doped into the HOF matrix using a solution impregnation method. 3+ Specifically, the HOF matrix prepared in step S1 is mixed and reacted with an organic solution of Tb salt to achieve Tb 3+ Coordination complexation with the HOF matrix, loading Tb onto the HOF matrix 3+ .

[0041] The specific doping ratio can be adjusted according to actual needs or determined experimentally. Those skilled in the art are capable of doing so. In some specific examples of this application, the mass ratio of the HOF matrix to the Tb salt is 1:(0.05~0.15). A suitable doping ratio can achieve better detection performance.

[0042] As described in this application, the organic solution of the Tb salt refers to a solution in which the solute is a Tb salt and the solvent is at least one of ethanol, methanol, isopropanol, or acetone. The Tb salt is either TbCl3·6H2O or Tb(NO3)3·6H2O. To ensure effective impregnation, preferably, the concentration of the Tb salt is 0.4~1.5 mg / mL.

[0043] During the impregnation process, stirring is used to achieve a better impregnation effect. The specific stirring time can be adjusted as needed without special limitations; as a preferred example, the stirring time is 2-10 hours. It is understood that after stirring, post-processing steps such as centrifugation, washing, and drying are also included, for example, washing with ethanol and drying completely at 60-80°C, which will not be elaborated here.

[0044] The third aspect of this application discloses Tb as described in the first aspect of this application. 3+ Tb doped HOF materials or prepared using the method described in the second aspect of this application 3+ Application of HOF-doped materials as fluorescent probes in the detection of hypochlorite, particularly in the detection of the explosive precursor NaClO, where they exhibit low detection limits, wide linear ranges, and ultra-high sensitivity.

[0045] The fourth aspect of this application discloses a kit for detecting sodium hypochlorite, an explosive precursor, wherein the kit contains the Tb described in the first aspect of this application. 3+ Tb doped HOF materials or prepared using the method described in the second aspect of this application 3+ Doped HOF materials.

[0046] In this application, the kit refers to a type of detection tool that, in addition to containing the fluorescent probe necessary for detection (Tb as described in this application), also contains the fluorescent probe (Tb as described in this application). 3+ The kit (doped with HOF material) may also include containers, auxiliary reagents (such as solvents, control solutions, etc.), and instructions for use, which typically describe the steps for conducting the test and interpreting the results. The specific kit configuration can be adjusted by those skilled in the art as needed; therefore, there are no particular limitations.

[0047] The fifth aspect of this application discloses a method for detecting sodium hypochlorite, a precursor to explosives, comprising the following steps:

[0048] Tb 3+ Aqueous dispersions were prepared by doping HOF materials;

[0049] The sample to be tested was added to the aqueous dispersion and mixed thoroughly. The fluorescence emission intensity at 545 nm was then detected under 330 nm excitation light.

[0050] The content of NaClO in the sample to be tested was obtained based on the linear relationship equation between NaClO solutions of different concentrations and fluorescence intensity.

[0051] It is understood that the linear relationship equations in this application can be obtained by the standard curve method well known in the art, which will not be elaborated here.

[0052] In some examples of this application, the aqueous dispersion contains Tb 3+ The concentration of HOF-doped materials is 1~3 mg / mL.

[0053] The present application will be further illustrated below with reference to specific embodiments. It should be noted that the specific embodiments below are for illustrative purposes only and do not limit the scope of the present application in any way.

[0054] Unless otherwise defined, 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 application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0055] In addition, unless otherwise specified, methods without detailed conditions or steps are conventional methods, and the reagents and materials used are commercially available.

[0056] Example 1

[0057] This embodiment discloses a method for preparing Tb@HOF material, the raw materials of which include pyromellitic ester (PMA) and metformin hydrochloride (MET), referred to as Tb@PMA-MET material in this embodiment, and the reaction process is as follows:

[0058]

[0059] The specific steps are as follows:

[0060] (1) Weigh 600mg PMA and 300mg MET, dissolve them in 60mL methanol, and sonicate for 10min to disperse them fully and form a uniform mixture.

[0061] (2) Place the mixture from step (1) in a beaker and let it stand at room temperature for 24 hours to evaporate.

[0062] (3) After the reaction is complete, the white precipitate generated is collected by centrifugation, washed three times with ethanol, and dried in an oven at 80°C for 6 hours to obtain the HOF matrix.

[0063] (4) Weigh 100 mg of the HOF matrix obtained in step (3), add 5 mL of TbCl3·6H2O ethanol solution with a concentration of 1.0 mg / mL, and stir at room temperature for 6 h.

[0064] (5) After the reaction is complete, the solid is collected by centrifugation, washed three times with ethanol, and dried at 80°C for 3 hours to obtain the target product Tb@PMA-MET.

[0065] The Tb@PMA-MET material in Example 1 was characterized, and the results are as follows: Figures 1-4 .

[0066] SEM analysis revealed that the Tb@PMA-MET material exhibits a micron-scale rod / plate-like structure. Figure 1 EDS spectra confirmed the presence of C, N, O, and Tb elements in the material. Figure 2 The fluorescence spectrum showed Tb under 330 nm excitation. 3+ Characteristic emission peak (545nm) Figure 3 The shift of the C=O stretching vibration peak in the infrared spectrum proves that Tb 3+ Successful coordination with carboxyl groups ( Figure 4 (A); XRD patterns show that the characteristic diffraction peaks of HOF were retained after doping, indicating that the crystal structure was not destroyed. Figure 4 (B)

[0067] Application Example 1

[0068] Taking the Tb@PMA-MET material prepared in Example 1 as an example, its performance in detecting NaClO was tested. The specific steps are as follows:

[0069] (1) Disperse the Tb@PMA-MET material prepared in Example 1 in ultrapure water to prepare a suspension of 1 mg / mL and sonicate for 10 min for later use.

[0070] (2) Take 100 μL of the above suspension into a cuvette, add 10 μL of NaClO standard solution of different concentrations, and vortex to mix.

[0071] (3) Immediately use a fluorescence spectrometer to test and record the fluorescence intensity at 545 nm under 330 nm excitation.

[0072] (4) Plot a standard curve with the logarithm of NaClO concentration (x, g / mL) on the x-axis and the fluorescence intensity (y) at 545 nm on the y-axis. For example... Figure 5 As shown, a good linear relationship is observed within the test range, and the linear equation is:

[0073]

[0074] The calculated limit of detection (LOD) was 104 ng / mL, and the linear range was 100-100000 ng / mL.

[0075] The limit of detection (LOD) is determined using the following method:

[0076] The fluorescence intensity of the blank solution was measured in 11 parallel runs, and the standard deviation (σ) was calculated. The LOD was calculated using the formula LOD = 3σ / S, based on the slope (S) of the calibration curve.

[0077] The lower limit of the linear range is set above the method detection limit (LOD) to ensure the reliability of the quantitative analysis.

[0078] (5) Conduct selective and anti-interference tests.

[0079] In the selectivity experiment, Tb@PMA-MET material was prepared into an aqueous dispersion of 1 mg / mL. 100 μL of this dispersion was then added to either 10 μL of a 10 μg / mL sodium hypochlorite (NaClO) solution or a 100 μg / mL solution of one of the following interfering substances: KClO3, NaClO3, KClO4, KNO3, KI, NaBr, KCl, Na2SO4, or H2O2. A separate control group was prepared by adding 10 μL of ultrapure water. After mixing, the fluorescence intensity at 545 nm under 330 nm excitation light was measured.

[0080] In the anti-interference experiment, Tb@PMA-MET material was prepared into an aqueous dispersion of 1 mg / mL. 100 μL of this dispersion was taken, and 10 μL of each of the aforementioned interfering agents (100 μg / mL) was added to each tube. Then, 10 μL of NaClO solution (10 μg / mL) was added to each tube. A blank control group was prepared by adding 20 μL of ultrapure water. After mixing, the fluorescence intensity at 545 nm under 330 nm excitation light was measured.

[0081] The results are as follows Figure 6 As shown, the Tb@PMA-MET material prepared in this application has high selectivity and strong anti-interference ability for NaClO, and common ions and oxidants do not interfere with its detection.

[0082] Example 2

[0083] This embodiment discloses another method for preparing Tb@PMA-MET material, which is the same as the method in Example 1, except that the concentration of the TbCl3·6H2O ethanol solution in step (4) is 2.0 mg / mL (5 mL is used, i.e., the amount of Tb salt added is 10 mg), so that the mass ratio of HOF matrix to Tb salt is 1:0.10. Other process steps and parameter conditions are the same as in Example 1.

[0084] Application Example 2

[0085] Referring to the method in Application Example 1, the performance of the Tb@PMA-MET material prepared in Example 2 in detecting NaClO was tested. A standard curve was plotted with the logarithm of NaClO concentration (x, g / mL) on the x-axis and the fluorescence intensity (y) at 545 nm on the y-axis. Figure 7 As shown, a good linear relationship is observed within the test range, and the linear equation is:

[0086]

[0087] The calculated limit of detection (LOD) was 244 ng / mL, and the linear range was 1000-100000 ng / mL.

[0088] Example 3

[0089] This embodiment discloses another method for preparing Tb@PMA-MET material, which is the same as the method in Example 1, except that the concentration of the TbCl3·6H2O ethanol solution in step (4) is 3.0 mg / mL (5 mL is used, i.e., the amount of Tb salt added is 15 mg), so that the mass ratio of HOF matrix to Tb salt is 1:0.15. Other process steps and parameter conditions are the same as in Example 1.

[0090] Application Example 3

[0091] Referring to the method in Application Example 1, the performance of the Tb@PMA-MET material prepared in Example 2 in detecting NaClO was tested. A standard curve was plotted with the logarithm of NaClO concentration (x, g / mL) on the x-axis and the fluorescence intensity (y) at 545 nm on the y-axis. Figure 8 As shown, a good linear relationship is observed within the test range, and the linear equation is:

[0092]

[0093] The calculated limit of detection (LOD) was 1100 ng / mL, and the linear range was 5000-500000 ng / mL.

[0094] From the above embodiments, it can be concluded that the Tb provided in this application 3+ HOF-doped materials exhibit excellent linear fluorescence response to sodium hypochlorite (R0). 2 With a linear range of >0.998, it is easy to operate and has a fast response, making it very suitable for rapid on-site quantitative detection.

[0095] It should be noted that the purpose of this application can be achieved when the preparation process of Tb@HOF material meets the following conditions:

[0096] Specifically, the polycarboxylic acid compounds can also be phthalic acid, terephthalic acid, isophthalic acid, 1,2,4-trisphthalic acid, and pyromellitic acid.

[0097] The mass ratio of benzene polycarboxylic acid compound to metformin hydrochloride is (1.8~2.2):1, specifically 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1.

[0098] Another type of Tb salt that can be compared to it is Tb(NO3)3·6H2O.

[0099] For other process parameters, those skilled in the art can make appropriate selections according to actual needs, all of which can achieve the purpose of this application, namely, to prepare a fluorescent probe material that can be specifically quenched by NaClO, and whose detection performance is comparable to that of Example 1.

[0100] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A terbium-doped benzene polycarboxylic acid-bismethylguanidine HOF material, characterized in that, It consists of an HOF matrix and rare earth metal ions Tb 3+ The HOF matrix is ​​composed of a coordination complex and is constructed by intermolecular hydrogen bonding self-assembly of a benzene polycarboxylic acid compound and metformin hydrochloride. The benzene polycarboxylic acid compound is at least one of phthalic acid, terephthalic acid, isophthalic acid, 1,2,4-benzenetricarboxylic acid, pyromellitic acid, and pyromellitic tetracarboxylic acid.

2. A method for preparing the terbium-doped benzene polycarboxylic acid-bismethyl guanidine (HOF) material as described in claim 1, characterized in that, Includes the following steps: The HOF matrix was obtained by hydrogen bonding self-assembly of a benzene polycarboxylic acid compound and metformin hydrochloride; The HOF matrix was mixed with an organic solution of Tb salt to prepare terbium-doped benzene polycarboxylic acid-bismethylguanidine HOF material.

3. The method as described in claim 2, characterized in that, The preparation of the HOF matrix includes the following steps: The benzene polycarboxylic acid compound and metformin hydrochloride were dissolved in methanol and dispersed thoroughly to obtain a homogeneous mixture. The mixture was allowed to stand at room temperature to evaporate, thus obtaining the HOF matrix. And / or, the mass ratio of the benzene polycarboxylic acid compound to metformin hydrochloride is (1.8~2.2):1; And / or, use 20-40 mL of methanol per 100 mg of metformin hydrochloride.

4. The method as described in claim 2, characterized in that, The mass ratio of the HOF matrix to the Tb salt is 1:(0.05~0.15). And / or, in the organic solution of the Tb salt, the solvent is at least one of ethanol, methanol, isopropanol or acetone; And / or, in the organic solution of the Tb salt, the concentration of the Tb salt is 0.4~1.5 mg / mL; And / or, the Tb salt is TbCl3·6H2O or Tb(NO3)3·6H2O.

5. The application of the terbium-doped benzene polycarboxylic acid-bismethyl guanidine HOF material as described in claim 1 or the terbium-doped benzene polycarboxylic acid-bismethyl guanidine HOF material prepared by the method described in any one of claims 2-4 as a fluorescent probe in the detection of hypochlorite.

6. The application as described in claim 5, characterized in that, The application is for detecting NaClO, a precursor to explosives.

7. A kit for detecting sodium hypochlorite, a precursor to explosives, characterized in that, The kit contains the terbium-doped benzene polycarboxylic acid-bismethyl guanidine HOF material as described in claim 1 or the terbium-doped benzene polycarboxylic acid-bismethyl guanidine HOF material prepared by the method described in any one of claims 2-4.

8. A method for detecting sodium hypochlorite, a precursor to explosives, characterized in that, Includes the following steps: A terbium-doped benzene polycarboxylic acid-bismethyl guanidine (HOF) material was formulated into an aqueous dispersion, wherein the terbium-doped benzene polycarboxylic acid-bismethyl guanidine (HOF) material is the terbium-doped benzene polycarboxylic acid-bismethyl guanidine (HOF) material described in claim 1 or prepared by the method described in any one of claims 2-4; The sample to be tested was added to the aqueous dispersion and mixed thoroughly. The fluorescence emission intensity at 545 nm was then detected under 330 nm excitation light. The content of NaClO in the sample to be tested was obtained based on the linear relationship equation between NaClO solutions of different concentrations and fluorescence intensity.

9. The method as described in claim 8, characterized in that, The concentration of terbium-doped benzene polycarboxylic acid-bismethylguanidine (HOF) material in the aqueous dispersion is 1-3 mg / mL.

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