Porous materials, their applications, methods of preparation and detection

Abstract

This invention provides porous materials, their applications, preparation methods, and detection methods. The porous materials are synthesized by modifying the reaction product of a metal inorganic salt and a ligand molecule with functional groups. The ligand molecule has the general formula R1, R2, and R3, and R1, R2, and R3 can be any of the following groups: R1, R2, and R3 cannot simultaneously be -H. This invention has advantages such as low detection limits.

Description

Technical Field

[0001] This invention relates to materials technology, and in particular to porous materials and their applications, preparation methods and detection methods. Background Technology

[0002] In recent years, with the continuous improvement of people's living standards and the advancement of chemical synthesis technology, a large number of toxic and harmful substances have emerged every year, such as organophosphorus pesticides, new antibiotics, and drugs, which seriously affect people's health and environmental safety. Organophosphorus pesticides are among the most widely used pesticides in the world, including in my country, and can effectively protect crops; antibiotics play an important role in clinical practice and are widely used in the treatment of various inflammations; in addition, the abuse of opioids, amphetamine stimulants (such as methamphetamine and ecstasy), and marijuana has become a global problem, seriously threatening human health and social security. The abuse of these toxic and harmful substances has led to the exceeding of standards for toxic and harmful substances in environments such as rivers, lakes, and drinking water, which indirectly affects human health and life. Therefore, detecting toxic and harmful substances in environmental water samples is beneficial for relevant government departments and law enforcement agencies to understand the abuse of toxic and harmful substances in a timely manner, and the relevant test results can also be used to assess the safety of the aquatic environment and ecosystem.

[0003] Currently, the following technologies are used to detect toxic and hazardous substances:

[0004] 1. Chemical colorimetric method: Characterized by rapid qualitative detection, it is mainly used for on-site detection of toxic and hazardous substances. However, it has a low detection limit, poor specificity, and cannot detect trace amounts of toxic and hazardous substances with similar chemical structures. The test results of the colorimetric method have limitations.

[0005] 2. Chromatography, among which thin-layer chromatography uses relatively simple experimental equipment and can be used as both an analytical method and a separation technique. It is mainly used for samples with simple compositions in the laboratory. High-performance liquid chromatography (HPLC) is suitable for the detection of toxic and harmful substances with poor stability, large molecular weight, and easy oxidation.

[0006] 3. Spectroscopic methods have certain requirements for sample purity in the detection of toxic and hazardous substances, and are not suitable for complex systems. Moreover, fluorescence spectroscopy and ultraviolet spectrophotometry, which are applicable to the detection of samples in solutions, are affected by different solvents and temperatures. Therefore, the application of spectroscopic methods in the detection of toxic and hazardous substances is limited to a certain extent.

[0007] 4. Colloidal gold method: Test strips or kits for detecting toxic and harmful substances utilize immunochromatography. While simple and convenient, this method is affected by ambient temperature and human error, and cannot detect low concentrations of toxic and harmful substances, often resulting in false positives. Furthermore, it is limited in its detection capabilities; a single test strip can only detect one type of hazard, leading to a certain false positive rate. Since environmental samples typically contain only trace levels of toxic and harmful substances and their metabolites, sample pretreatment techniques are necessary to enrich and concentrate the target analytes before testing.

[0008] MOFs are a class of porous coordination polymers composed of metal nodes or metal clusters linked to organic ligands. They are easy to synthesize, have tunable structures and highly developed pore structures, and possess ultra-high specific surface areas and a large number of tunable organic ligand active sites, making them promising for applications in the analytical field.

[0009] However, current MOFs are not suitable for the detection of toxic and hazardous substances. Summary of the Invention

[0010] To address the shortcomings of the existing technical solutions, the present invention provides a porous material.

[0011] The objective of this invention is achieved through the following technical solution:

[0012] A porous material, wherein the porous material is:

[0013] The reaction product of a metal inorganic salt and a ligand molecule is synthesized by modifying it with functional groups. The general formula of the ligand molecule is as follows: R1, R2, and R3 are any of the following groups:

[0014] R1, R2, and R3 cannot all be -H at the same time.

[0015] Another object of the present invention is to provide a method for preparing porous materials, which is achieved through the following technical solution:

[0016] According to the method for preparing porous materials of the present invention, the preparation method includes the following steps:

[0017] (A1) Metal inorganic salts react with ligand molecules to yield reaction products of elementary elements;

[0018] (A2) The reaction product reacts with a functional group containing a targeted functional group, thereby modifying the reaction product with a functional group to obtain a porous material;

[0019] (A3) The porous material is aged in a poor solvent, followed by filtration and pore morphology curing.

[0020] Another object of the present invention is to provide the application of porous materials in the detection of toxic and hazardous substances, namely organophosphorus pesticides, antibiotics, or drugs.

[0021] Another objective of this invention is to provide a method for detecting toxic and harmful substances, which is achieved through the following technical solution:

[0022] A method for detecting toxic and hazardous substances, the method comprising the following steps:

[0023] (S1) The liquid sample comes into contact with the porous material of the present invention;

[0024] (S2) The desorbent is added to the porous material to desorb toxic and harmful substances;

[0025] (S3) Toxic and harmful substances are ionized and sent to a mass spectrometer.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] In terms of sample pretreatment, porous materials possess tunable organic ligand active sites and adjustable pore sizes (meaning the pore size of porous materials can be adjusted by optimizing synthesis conditions; the organic ligand active sites can be replaced with active sites suitable for post-modification, which can be used to introduce functional groups). Based on these characteristics, the porous materials of this invention are used for solid-phase microextraction to adsorb and enrich harmful and toxic substances. Combined with direct ionization mass spectrometry, this not only enables the rapid extraction and enrichment of toxic and harmful substances in environmental water bodies, but also allows for in-situ, real-time, rapid, and non-destructive detection of samples, providing new ideas for further promoting the development of novel detection methods. Attached Figure Description

[0028] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are merely illustrative of the technical solutions of this invention and are not intended to limit the scope of protection of this invention. In the drawings:

[0029] Figure 1 These are electron microscope images of porous materials according to embodiments of the present invention;

[0030] Figure 2 This is a pore size distribution diagram of the porous material according to an embodiment of the present invention;

[0031] Figure 3 This is an adsorption-desorption curve of the porous material according to an embodiment of the present invention;

[0032] Figure 4 These are the primary and secondary spectra of quinalphos;

[0033] Figure 5 This is a schematic diagram showing the relationship between the mass spectrometry peak intensity and concentration of quinalphos.

[0034] Figure 6 This is a graph showing the relationship between the number of times the product can be reused and the recovery rate of quinthion.

[0035] Figure 7 These are the primary and secondary spectra of methylpyrimidine phosphate;

[0036] Figure 8 This is a schematic diagram showing the relationship between the mass spectrum peak intensity and concentration of methylpyrimidine phosphorus;

[0037] Figure 9 This is a graph showing the relationship between the number of times the material can be reused and the recovery rate of p-methylpyrimidine phosphate.

[0038] Figure 10 These are the primary and secondary spectra of fenthion;

[0039] Figure 11 This is a schematic diagram showing the relationship between the mass spectrometry peak intensity and concentration of fenthion;

[0040] Figure 12 This is a graph showing the relationship between the number of times it can be reused and the recovery rate of parathion;

[0041] Figure 13 These are the primary and secondary spectra of triazophos;

[0042] Figure 14 This is a schematic diagram showing the relationship between the mass spectrum peak intensity and concentration of triazophos;

[0043] Figure 15 This is a graph showing the relationship between the number of times the device can be reused and the recovery rate of triazophos.

[0044] Figure 16 These are the primary and secondary spectra of chlorpyrifos;

[0045] Figure 17 This is a schematic diagram showing the relationship between the mass spectrometry peak intensity and concentration of chlorpyrifos;

[0046] Figure 18 This is a graph showing the relationship between the number of times the compound can be reused and the recovery rate of chlorpyrifos. Detailed Implementation

[0047] Figures 1-18The following description illustrates optional embodiments of the invention to teach those skilled in the art how to implement and reproduce the invention. Some conventional aspects have been simplified or omitted to teach the technical solutions of the invention. Those skilled in the art should understand that variations or substitutions derived from these embodiments will be within the scope of the invention. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of the invention. Therefore, the invention is not limited to the optional embodiments described below, but is defined only by the claims and their equivalents.

[0048] Example 1:

[0049] A porous material according to Embodiment 1 of the present invention, wherein the porous material is:

[0050] The reaction product of a metal inorganic salt and a ligand molecule is synthesized by modifying it with functional groups. The general formula of the ligand molecule is as follows: R1, R2, and R3 are any of the following groups:

[0051] R1, R2, and R3 cannot all be -H at the same time.

[0052] To further modify the reaction product with functional groups, the reaction product is further reacted with a compound containing a targeted functional group, thereby modifying the reaction product with functional groups.

[0053] To facilitate the detection of toxic and hazardous substances, furthermore, when R1, R2, or R3 is -NH2, the functional group is any one of the following:

[0054]

[0055] When R1, R2, or R3 is -OH, the functional group is any one of the following:

[0056]

[0057] The method for preparing porous materials in this embodiment includes the following steps:

[0058] (A1) Metal inorganic salts react with ligand molecules to yield reaction products of elementary elements;

[0059] (A2) The reaction product reacts with a functional group containing a targeted functional group, thereby modifying the reaction product with a functional group to obtain a porous material;

[0060] (A3) The porous material is aged in a poor solvent, followed by filtration and pore morphology curing.

[0061] To ensure efficient reaction, the unsuitable solvent is further defined as an alkane or an alcohol solvent;

[0062] In step (A2), the solvent required for the reaction is N,N-dimethylformamide, ethanol or tetrahydrofuran, and the temperature is 70℃-160℃.

[0063] To ensure efficient reaction, a hydrothermal reaction further occurs in step (A1) under the following conditions:

[0064] Pressure 2MPa-20MPa, temperature 80℃-200℃.

[0065] This invention relates to the application of porous materials in the detection of toxic and hazardous substances, where the toxic and hazardous substances are organophosphorus pesticides, antibiotics, or narcotics, such as:

[0066] The organophosphorus pesticides are dichlorvos, acetamiprid, triazophos, cyhalothrin, amitraz, prochloraz, methomyl, quinalphos, chlorpyrifos, fenthion, or methyl parathion; the antibiotics are linezolid, cilastatin, sulbactam, voriconazole, moxifloxacin, or piperacillin-tigecycline; and the drugs are estazolam, codeine, zopiclone, tramadol, methamphetamine, ketamine, morphine, temazepam, flumethoxazole, acetylcodeine, or heroin.

[0067] An embodiment of the present invention provides a method for detecting toxic and harmful substances, the method comprising the following steps:

[0068] (S1) The liquid sample comes into contact with the porous material of the present invention;

[0069] (S2) The desorbent is added to the porous material to desorb toxic and harmful substances;

[0070] (S3) Toxic and harmful substances are ionized and sent to a mass spectrometer.

[0071] To improve detection efficiency, in step (S1), the porous material and the liquid sample are mixed to obtain a porous material containing toxic and harmful substances; in step (S2), an ultrasonic agent containing toxic and harmful substances is obtained.

[0072] Alternatively, in step (S1), the porous material is fixed to the inner wall of the capillary, and the liquid sample passes through the capillary; in step (S2), the desorbent is introduced into the capillary.

[0073] Example 2:

[0074] Examples of applications of porous materials, preparation methods, and detection methods according to Embodiment 1 of the present invention.

[0075] In this application example, the method for preparing the porous material is as follows:

[0076] (A1) Add the raw materials to be reacted into the reaction vessel, and add 0.7g of ZrCl4 and 0.7g of ligand molecule (Ⅰ) in sequence, where R1 and R3 are -NH2 and R2 is -H, 3mL of H2O and 40mL of DMF. The above mixed solution is ultrasonically dispersed for 30min, and then stirred for 30min.

[0077] The reaction vessel was sealed and placed in a forced-air drying oven at a pressure of 10 MPa for 24 hours. After the reaction, the elementary porous material was obtained by centrifugation, and then washed three times with DMF and methanol respectively, and dried overnight in a vacuum oven at 80°C to obtain the material for subsequent experiments.

[0078] (A2) Add 0.3g of the basic porous material obtained above into a round-bottom flask, followed by 80mL of anhydrous acetonitrile and 2g of functional group (Ⅲ) 1.

[0079] Under argon protection, the mixture was heated and stirred at 70°C for 3 days.

[0080] (A3) After the reaction is complete, the porous material is separated by centrifugation, washed three times with anhydrous acetonitrile, and dried overnight in a vacuum oven at 80°C to obtain the porous material for subsequent adsorption.

[0081] The porous material prepared above was dispersed in an ethanol solution. The bottom sample (2 μL) was taken out with a pipette and dropped onto a clean silicon wafer surface. After the solution evaporated, it was placed in an ion sputtering machine (Leica). After the vacuum was evaporated to a vacuum degree of 10-15 Pa, metallic platinum particles were sputtered onto its surface for 120 s.

[0082] The silicon wafer was removed and placed under a scanning electron microscope (Hitachi S4800) to observe its morphology, such as... Figure 1 As shown in the electron microscope image, the porous material is a small sphere with a large specific surface area, which can be used for the adsorption of trace pollutants in water.

[0083] The porous material of this embodiment was tested and analyzed using a specific surface area and pore size distribution measuring instrument. The results are as follows:

[0084] like Figure 2 As shown, porous materials have a structure dominated by micropores, demonstrating that they have a certain degree of pore-channel filtering ability.

[0085] like Figure 3 As shown, based on the adsorption-desorption curves of the porous material, its specific surface area was calculated to be 948.53 m². 2 / g.

[0086] The porous material prepared in this embodiment was used to verify its detection performance for quinalphos, as detailed below:

[0087] Direct ionization mass spectrometry was used to detect quinthionine standard solutions of different concentrations to determine the detection performance of direct ionization mass spectrometry.

[0088] Weigh 1.0 mg of the prepared porous material into a centrifuge tube, add 990 μL of water sample treated with hydrophobic PTFE, then add 10 μL of 10 ppm quinthion standard solution into the centrifuge tube, shake for 10 min, and centrifuge at 10000 rpm for 1 min; use a syringe to aspirate and discard the supernatant from the tube, add 500 μL of methanol to the centrifuge tube again, sonicate at 30℃ for 5 min, and centrifuge for 1 min; use a syringe to aspirate the desorption solution for analysis;

[0089] The targeted extraction performance of the porous material in this embodiment was evaluated by detecting the desorption solution using direct ionization mass spectrometry. The specific steps are as follows:

[0090] 1) Perform three parallel measurements on the desorption solution, with the methanol solution serving as the control group;

[0091] 2) Take the average value of the three results and substitute it into the standard curve equation to obtain the concentration of quinthion in the desorption solution;

[0092] 3) Compare the concentration of the test solution with the corresponding concentration of the standard solution to obtain the recovery rate;

[0093] 4) such as Figure 4 As shown, the mass spectrum peaks of quinthion are clearly visible in the mass spectrum, with no obvious background noise.

[0094] like Figure 5 As shown, the concentration of quinalphos showed a good linear relationship with the detection intensity, with the linear equation being y = 0.5609x - 14.2976, a linear range of 0.1 ppb - 1 ppm, and a correlation coefficient of 0.9990. This indicates that direct ionization mass spectrometry has a low detection limit and a wide detection range for quinalphos, and has good application value; its detection limit is 0.1055 ng / mL.

[0095] The reusability of a material is one of the important factors in evaluating its performance. In order to further evaluate the reusability of the material, we need to verify the changes in its performance after multiple adsorption cycles.

[0096] like Figure 6 As shown, the recovery rate of quinalphos from the porous material changes after multiple reuses. Although the recovery rate varies with each reuse, it is above 95%, indicating that the MOF material can be reused at least 10 times.

[0097] The porous material prepared in this embodiment was used to verify its detection performance for methylpyrimidine phosphorus, as detailed below:

[0098] Direct ionization mass spectrometry was used to detect methylpyrimidine phosphorus standard solutions of different concentrations to determine the detection performance of direct ionization mass spectrometry.

[0099] Weigh 1.0 mg of the prepared porous material into a centrifuge tube, add 990 μL of water sample treated with hydrophobic PTFE, then add 10 μL of 10 ppm methylpyrimidine phosphorus standard solution into the centrifuge tube, shake for 10 min, and centrifuge at 10000 rpm for 1 min; use a syringe to aspirate and discard the supernatant from the tube, add 500 μL of methanol to the centrifuge tube again, sonicate at 30℃ for 5 min, and centrifuge for 1 min; use a syringe to aspirate the desorption solution for analysis;

[0100] The targeted extraction performance of the porous material in this embodiment was evaluated by detecting the desorption solution using direct ionization mass spectrometry. The specific steps are as follows:

[0101] 1) Perform three parallel measurements on the desorption solution, with the methanol solution serving as the control group;

[0102] 2) Take the average value of the three results and substitute it into the standard curve equation to obtain the concentration of methylpyrimidine phosphorus in the desorption solution;

[0103] 3) Compare the concentration of the test solution with the corresponding concentration of the standard solution to obtain the recovery rate;

[0104] 4) such as Figure 7 As shown, the mass spectrum peaks of methylpyrimidine phosphorus are clearly visible, with no obvious background noise.

[0105] like Figure 8 As shown, the concentration of methylpyrimidine phosphorus exhibits a good linear relationship with the detection intensity, with the linear equation being y = 5.3851x + 67.6592, a linear range of 10 ppb-1 ppm, and a correlation coefficient of 0.9998. This indicates that direct ionization mass spectrometry has a low detection limit and a wide detection range for methylpyrimidine phosphorus, making it a valuable application. Its detection limit is 0.0958 ng / mL.

[0106] The reusability of a material is one of the important factors in evaluating its performance. In order to further evaluate the reusability of the material, we need to verify the changes in its performance after multiple adsorption cycles.

[0107] like Figure 9 As shown, the recovery rate of methylpyrimidine phosphorus from the porous material changes after multiple reuses. Although the recovery rate varies with each reuse, it is always above 100%, indicating that the MOF material can be reused at least 10 times.

[0108] The porous material prepared in this embodiment was used to verify its detection performance for fenthion, as detailed below:

[0109] Direct ionization mass spectrometry was used to detect phosmet standard solutions of different concentrations to determine the detection performance of direct ionization mass spectrometry.

[0110] Weigh 1.0 mg of the prepared porous material into a centrifuge tube, add 990 μL of water sample treated with hydrophobic PTFE, then add 10 μL of 10 ppm fenthion standard solution into the centrifuge tube, shake for 10 min, and centrifuge at 10000 rpm for 1 min; use a syringe to aspirate and discard the supernatant from the tube, add 500 μL of methanol to the centrifuge tube again, sonicate at 30℃ for 5 min, and centrifuge for 1 min; use a syringe to aspirate the desorption solution for analysis;

[0111] The targeted extraction performance of the porous material in this embodiment was evaluated by detecting the desorption solution using direct ionization mass spectrometry. The specific steps are as follows:

[0112] 1) Perform three parallel measurements on the desorption solution, with the methanol solution serving as the control group;

[0113] 2) Take the average value of the three results and substitute it into the standard curve equation to obtain the concentration of phosphine in the desorbed solution;

[0114] 3) Compare the concentration of the test solution with the corresponding concentration of the standard solution to obtain the recovery rate;

[0115] 4) such as Figure 10 As shown, the mass spectrum peaks of thiophosphoric acid are clearly visible in the mass spectrum, with no obvious background noise.

[0116] like Figure 11 As shown, the concentration of fenthionite exhibits a good linear relationship with the detection intensity, with the linear equation being y = 0.197x - 0.2295, a linear range of 10 ppb - 1 ppm, and a correlation coefficient of 0.9992. This indicates that direct ionization mass spectrometry has a low detection limit and a wide detection range for fenthionite, making it a valuable application. The detection limit is 0.0773 ng / mL.

[0117] The reusability of a material is one of the important factors in evaluating its performance. In order to further evaluate the reusability of the material, we need to verify the changes in its performance after multiple adsorption cycles.

[0118] like Figure 12 As shown, the recovery rate of phosmet from the porous material changes after multiple reuses. Although the recovery rate varies with each reuse, it is above 106%, indicating that the MOF material can be reused at least 10 times.

[0119] The porous material prepared in this embodiment was used to verify its detection performance for triazophos, as detailed below:

[0120] Direct ionization mass spectrometry was used to detect triazophos standard solutions of different concentrations to determine the detection performance of direct ionization mass spectrometry.

[0121] Weigh 1.0 mg of the prepared porous material into a centrifuge tube, add 990 μL of water sample treated with hydrophobic PTFE, then add 10 μL of 10 ppm triazole phosphate standard solution into the centrifuge tube, shake for 10 min, and centrifuge at 10000 rpm for 1 min; use a syringe to aspirate and discard the supernatant in the tube, add 500 μL of methanol to the centrifuge tube again, sonicate at 30℃ for 5 min, and centrifuge for 1 min; use a syringe to aspirate the desorption solution for analysis;

[0122] The targeted extraction performance of the porous material in this embodiment was evaluated by detecting the desorption solution using direct ionization mass spectrometry. The specific steps are as follows:

[0123] 1) Perform three parallel measurements on the desorption solution, with the methanol solution serving as the control group;

[0124] 2) Take the average value of the three results and substitute it into the standard curve equation to obtain the triazophos concentration in the desorption solution;

[0125] 3) Compare the concentration of the test solution with the corresponding concentration of the standard solution to obtain the recovery rate;

[0126] 4) such as Figure 13 As shown, the mass spectrum peaks of triazole phosphorus are clearly visible in the mass spectrum, with no obvious background noise.

[0127] like Figure 14 As shown, the concentration of triazophos showed a good linear relationship with the detection intensity, with the linear equation being y = 3.1295x - 3.0855, the linear range being 10 ppb - 1 ppm, and the correlation coefficient being 0.9998. This indicates that direct ionization mass spectrometry has a low detection limit and a wide detection range for triazophos, and has good application value; its detection limit is 0.0987 ng / mL.

[0128] The reusability of a material is one of the important factors in evaluating its performance. In order to further evaluate the reusability of the material, we need to verify the changes in its performance after multiple adsorption cycles.

[0129] like Figure 15 As shown, the recovery rate of triazophos from the porous material changes after multiple reuses. Although the recovery rate varies with each reuse, it is above 104%, indicating that the MOF material can be reused at least 10 times.

[0130] An embodiment of the present invention provides a method for detecting toxic and harmful substances, the method comprising the following steps:

[0131] (S1) Add the porous material to the liquid sample, then mix the material and the liquid thoroughly by vortexing, and then remove the liquid by centrifugation to take out the solid material;

[0132] (S2) Add the desorbent (acetonitrile) to the solid material and ultrasonically vibrate to obtain a desorbent containing toxic and harmful substances;

[0133] (S3) The above desorbents are detected by direct ionization mass spectrometry to obtain the content of toxic and harmful substances in the liquid sample, such as the content of quinthion, methyl pyrimidine phosphorus or fenthion.

[0134] Example 3:

[0135] Examples of applications of porous materials, preparation methods, and detection methods according to Embodiment 1 of the present invention.

[0136] The method for preparing porous materials according to embodiments of the present invention is as follows:

[0137] (A1) Add the raw materials to be reacted into the reaction vessel, and add 0.7g of ZrCl4, 1.5g of ligand molecule (Ⅰ) in sequence, where R1 and R3 are respectively 3 in formula (Ⅱ), R2 is -H, 2.5mL of H2O and 40mL of DMF. The above mixed solution is ultrasonically dispersed for 30min, and then stirred for 30min.

[0138] The reaction vessel was sealed and placed in a forced-air drying oven at a pressure of 12 MPa for 48 hours. After the reaction, the elementary porous material was obtained by centrifugation, and then washed three times with DMF and methanol respectively, and dried overnight in a vacuum oven at 80°C to obtain the material for subsequent experiments.

[0139] (A1) Add 0.3 g of the above-obtained elementary MOF-2 material to a round-bottom flask, followed by 120 mL of anhydrous acetonitrile and 2 g of functional group (Ⅳ). Heat under argon protection and reflux for 3 days.

[0140] (A3) After the reaction is complete, the porous material is separated by centrifugation, washed three times with anhydrous acetonitrile, and dried overnight in a vacuum oven at 80°C to obtain the porous material for subsequent adsorption.

[0141] The porous material prepared in this embodiment was used to verify its detection performance for chlorpyrifos, as detailed below:

[0142] Direct ionization mass spectrometry was used to detect chlorpyrifos standard solutions of different concentrations to determine the detection performance of direct ionization mass spectrometry.

[0143] Weigh 1.0 mg of the prepared porous material into a centrifuge tube, add 990 μL of water sample treated with hydrophobic PTFE, then add 10 μL of 10 ppm chlorpyrifos standard solution into the centrifuge tube, shake for 10 min, and centrifuge at 10000 rpm for 1 min; use a syringe to aspirate and discard the supernatant from the tube, add 500 μL of methanol to the centrifuge tube again, sonicate at 30℃ for 5 min, and centrifuge for 1 min; use a syringe to aspirate the desorption solution for testing;

[0144] The targeted extraction performance of the porous material in this embodiment was evaluated by detecting the desorption solution using direct ionization mass spectrometry. The specific steps are as follows:

[0145] 1) Perform three parallel measurements on the desorption solution, with the methanol solution serving as the control group;

[0146] 2) Take the average value of the three results and substitute it into the standard curve equation to obtain the concentration of chlorpyrifos in the desorption solution;

[0147] 3) Compare the concentration of the test solution with the corresponding concentration of the standard solution to obtain the recovery rate;

[0148] 4) such as Figure 16 As shown, the mass spectrum peaks of chlorpyrifos are clearly visible in the mass spectrum, with no obvious background noise.

[0149] like Figure 17 As shown, the concentration of chlorpyrifos showed a good linear relationship with the detection intensity, with the linear equation being y = 0.8292x + 49.2268, the linear range being 1 ppb-1 ppm, and the correlation coefficient being 0.9978. This indicates that direct ionization mass spectrometry has a low detection limit and a wide detection range for chlorpyrifos, and has good application value; its detection limit is 0.2506 ng / mL.

[0150] The reusability of a material is one of the important factors in evaluating its performance. In order to further evaluate the reusability of the material, we need to verify the changes in its performance after multiple adsorption cycles.

[0151] like Figure 18 As shown, the recovery rate of chlorpyrifos from the porous material changes after multiple reuses. Although the recovery rate varies with each reuse, it is above 104%, indicating that the MOF material can be reused at least 10 times.

[0152] An embodiment of the present invention provides a method for detecting toxic and harmful substances, the method comprising the following steps:

[0153] (S1) Fix the porous material of this embodiment to the inner wall of the capillary. The diameter of the inner wall of the capillary is 1-10 mm, and in this embodiment it is 2 mm.

[0154] Water containing toxic and harmful substances is directly introduced into the above-mentioned capillary tubes, where the toxic and harmful substances in the water are adsorbed by the porous material.

[0155] (S2) The desorbent (using methanol) is introduced into the capillary, and the toxic and harmful substances adsorbed on the porous material are desorbed and discharged with the desorbent;

[0156] (S3) Direct ionization mass spectrometry is used to detect desorbents containing toxic and harmful substances, thereby obtaining the content of toxic and harmful substances in liquid samples, such as the content of chlorpyrifos.

[0157] The above embodiments only verify the detection performance of the prepared porous material for organophosphorus pesticides, and it still has good detection performance for antibiotics and narcotics.

Claims

1. A porous material, wherein the porous material is: By synthesis of functional groups to the reaction product of metal inorganic salts and ligand molecules of general formula R1, R2 and R3 are any one of the following groups: R1, R2, and R3 cannot all be -H simultaneously; The reaction product reacts with a compound containing a targeted functional group to modify the reaction product with functional groups; When R1, R2, or R3 is -NH2, the functional group is any one of the following (III) types of groups: ； When R1, R2, or R3 is -OH, the functional group is any one of the following (IV) types of groups: 。 2. The porous material of claim 1, wherein, The inorganic metal salt is ZrCl4.

3. The method for preparing a porous material according to any one of claims 1-2, wherein the preparation method comprises the following steps: (A1) Metal inorganic salts react with ligand molecules to yield reaction products of elementary elements; (A2) The reaction product reacts with a functional group containing a targeted functional group, thereby modifying the reaction product with a functional group to obtain a porous material; (A3) The porous material is aged in a poor solvent, followed by filtration and pore morphology curing.

4. The method of claim 3, wherein the porous material is prepared by a method comprising: The unsuitable solvent is an alkane or an alcohol solvent; In step (A2), the solvent required for the reaction is N,N-dimethylformamide, ethanol or tetrahydrofuran, and the temperature is 70℃-160℃.

5. The method for preparing porous materials according to claim 3, characterized in that, In step (A1), a hydrothermal reaction occurs under the following conditions: Pressure 2MPa-20MPa, temperature 80℃-200℃.

6. The application of the porous material according to any one of claims 1 in the detection of toxic and hazardous substances, wherein the toxic and hazardous substances are organophosphorus pesticides, antibiotics, or narcotics.

7. The application according to claim 6, characterized in that, The organophosphorus pesticides are dichlorvos, acetamiprid, triazophos, cyhalothrin, amitraz, prochloraz, methomyl, quinalphos, chlorpyrifos, fenthion, or methyl parathion; the antibiotics are linezolid, cilastatin, sulbactam, voriconazole, moxifloxacin, or piperacillin-tigecycline; and the drugs are estazolam, codeine, zopiclone, tramadol, methamphetamine, ketamine, morphine, temazepam, flumethoxazole, acetylcodeine, or heroin.

8. A method for detecting toxic and hazardous substances, the method comprising the following steps: (S1) The liquid sample comes into contact with the porous material in claim 1; (S2) The desorbent is added to the porous material to desorb toxic and harmful substances; (S3) Toxic and harmful substances are ionized and sent to a mass spectrometer.

9. The detection method according to claim 8, characterized in that, In step (S1), the porous material and the liquid sample are mixed to obtain a porous material containing toxic and harmful substances; in step (S2), an absorbent containing toxic and harmful substances is obtained by ultrasound. Alternatively, in step (S1), the porous material is fixed to the inner wall of the capillary, and the liquid sample passes through the capillary; in step (S2), the desorbent is introduced into the capillary.

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