Rare-earth-based metal-organic framework as well as preparation method and application thereof

Abstract

The invention discloses a rare earth-based metal-organic framework and a preparation method and application thereof, the chemical formula of the rare earth-based metal-organic framework is [Ln2 (5-TIA) 3 (H2O) 3]. 3H2O, Ln represents a rare earth element Eu or Tb, Ln exists in an ion form, and 5-TIA is a nitrogen-containing five-membered heterocyclic ligand 5-(1H-1, 2, 4-triazole-1-yl) isophthalic acid. The preparation method comprises the following steps: under a hydrothermal condition, adding a rare earth salt, a ligand 5-(1H-1, 2, 4-triazole-1-yl) isophthalic acid and water into a reaction kettle, reacting at 140-160 DEG C for 24-72 hours, after the reaction is finished, naturally cooling to normal temperature, filtering, washing and drying to obtain a crystal, namely the rare earth-based metal-organic framework. The rare earth-based metal-organic framework can be used for detecting 1-hydroxypyrene in human urine.

Description

Technical Field

[0001] The present invention relates to the technical field of biomarker analysis, and particularly to a rare earth metal-organic framework and its preparation method and application. Background Art

[0002] Polycyclic aromatic hydrocarbons (PAHs) can cause various harms to the human body due to their toxicity, genotoxicity, mutagenicity and carcinogenicity. For example, they can cause damage to the respiratory system, circulatory system, and nervous system, and damage to the liver and kidneys. Therefore, PAHs are considered to be the most serious chemical carcinogens. PAHs exist in various media in our living environment, such as water, soil, air, and even our food. Among them, 1-hydroxypyrene (1-HP) is the final metabolite of PAHs in human urine and can be used as a very reliable biomarker for detecting the content of PAHs in the human body. Traditional 1-HP detection methods, such as high performance liquid chromatography, mass spectrometry, electrochemical sensor technology and colorimetry, etc., all have some insurmountable defects, including high instrument cost, complex pretreatment process, etc. In summary, it is very necessary to explore a material or method that can quickly and accurately detect 1-HP.

[0003] Compared with the above traditional methods, the luminescence sensors based on metal-organic frameworks (MOFs) have been widely used due to their advantages such as simple operation, good selectivity, and fast response speed. It is worth noting that rare earth metal-organic frameworks (Ln-MOFs) have excellent luminescence characteristics such as strong emission peaks, long luminescence lifetimes and high luminescence efficiencies, and thus have attracted much attention from researchers. However, there are relatively few research reports in the literature on using Ln-MOFs as luminescence sensors for detecting 1-HP in human urine, and reports on the ratio detection of 1-HP by Ln-MOFs are even rarer. Summary of the Invention

[0004] The purpose of the present invention is to provide a rare earth metal-organic framework and its preparation method and application, which can detect 1-HP in human urine.

[0005] In one aspect of the present invention, a rare earth metal-organic framework is proposed. According to an embodiment of the present invention, the chemical formula is [Ln2(5-TIA)3(H2O)3]·3H2O, where Ln represents rare earth element Eu or Tb, Ln exists in ionic form, and 5-TIA is a nitrogen-containing five-membered heterocyclic ligand 5-(1H-1,2,4-triazol-1-yl) isophthalic acid.

[0006] In another aspect of the present invention, the present invention provides a method for preparing a rare earth metal-organic framework. According to an embodiment of the present invention, the method comprises the following steps: Under hydrothermal conditions, a rare earth salt, a ligand 5-(1H-1,2,4-triazol-1-yl)isophthalic acid, and water are added to a reaction kettle, and the reaction is carried out at 140-160 °C for 24-72 h. After the reaction is completed, it is naturally cooled to room temperature, filtered, washed, and dried to obtain crystals, which are the rare earth metal-organic framework.

[0007] In addition, according to a method for preparing a rare earth metal-organic framework according to the above embodiment of the present invention, the following additional technical features may also be included:

[0008] In some embodiments of the present invention, the rare earth salt is at least one of rare earth nitrate and rare earth chloride.

[0009] In some embodiments of the present invention, the molar ratio of the rare earth salt, 5-(1H-1,2,4-triazol-1-yl)isophthalic acid to water is (0.8-1.5):1:(500-833).

[0010] In another aspect of the present invention, the present invention provides a ratiometric fluorescence detection material for a carcinogenic biomarker 1-hydroxypyrene. According to an embodiment of the present invention, the material comprises the above-mentioned rare earth metal-organic framework.

[0011] In another aspect of the present invention, the present invention provides a ratiometric fluorescence detection method for a carcinogenic biomarker 1-hydroxypyrene. According to an embodiment of the present invention, the method comprises the following steps: The above-mentioned rare earth metal-organic framework is ultrasonically dispersed in an N,N-dimethylformamide solution to obtain a suspension, a solution to be treated containing 1-hydroxypyrene (1-HP) is added to the suspension and shaken well, and after waiting for 30-240 s, a fluorescence emission spectrum of the mixed solution at an excitation wavelength of 293 nm is collected using a fluorescence spectrometer, and the intensity ratio of the characteristic peak at 414 nm to that of the rare earth metal-organic framework (Ln-MOF) is calculated to determine the concentration of 1-HP.

[0012] In addition, according to a ratiometric fluorescence detection method for a carcinogenic biomarker 1-hydroxypyrene according to the above embodiment of the present invention, the following additional technical features may also be included:

[0013] In some embodiments of the present invention, the concentration of the suspension is 0.25-1.0 mg / mL.

[0014] In some embodiments of the present invention, the concentration range of 1-hydroxypyrene in the solution to be treated is 0-52 μmol / L.

[0015] In some embodiments of the present invention, the waiting period ranges from 30-240 s, and actually 30 s is sufficient.

[0016] In another aspect of the present invention, the present invention provides a method for detecting the carcinogenic biomarker 1-hydroxypyrene in urine. According to an embodiment of the present invention, the ratio fluorescence detection method of the carcinogenic biomarker 1-hydroxypyrene is used for detection.

[0017] In another aspect of the present invention, the present invention provides a luminescent material. According to an embodiment of the present invention, it includes the rare earth metal-organic framework described above.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1) The present invention discloses a rare earth metal-organic framework material, namely Ln-MOF, whose synthesis method is simple, easy to crystallize, has a high synthesis yield, and good reproducibility.

[0020] 2) Its crystalline material has excellent luminescent characteristics such as strong emission peaks, long luminescence lifetimes, and high luminescence efficiencies, and a ratio fluorescence sensor for 1-HP detection is constructed. When 1-HP is added to this Ln-MOF, the peaks at 396 nm and 414 nm will increase, while the characteristic peaks of rare earth ions (Eu 3+ at 626 nm, Tb 3+ at 550 nm) will decrease, and the ratio of the intensity of the peak at 414 nm to the characteristic peak of rare earth ions (I 414 / I 626 or I 414 / I 550 ) shows a good linear relationship with the concentration of 1-HP. In addition, in the presence of interference from other urine components, this Ln-MOF can still accurately detect 1-HP.

[0021] 3) The Ln-MOF disclosed by the present invention can generate a ratio-type luminescent signal, making the detection result more accurate. It can achieve rapid detection of trace 1-HP within 30 s, with a detection limit of up to 1.04 μmol / L, and has excellent selectivity and anti-interference ability.

[0022] 4) The Ln-MOF disclosed by the present invention also has good detection effects on the detection of 1-HP in actual urine samples, with high credibility. At the same time, this fluorescence sensor does not require cumbersome sample preparation and the operation of professional personnel. It shows that the Ln-MOF synthesized by this method has good application potential in the detection of 1-HP. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the coordination environment diagram of Eu1(a) and Eu2(b) in the structure of Eu-based Ln-MOF in Example 2 of the present invention;

[0024] Figure 2 These are three different coordination mode diagrams of the 5-TIA ligand in the structure of the Eu-based Ln-MOF in Example 2 of the present invention;

[0025] Figure 3 This is the three-dimensional structure diagram of the Eu-based Ln-MOF in Example 2 of the present invention;

[0026] Figure 4 This is the solid fluorescence spectrum diagram of the Ln-MOF prepared in Examples 2 and 3 of the present invention;

[0027] Figure 5 These are the fluorescence spectrum diagram (a) of the Eu-based Ln-MOF in Example 4 of the present invention in response to different concentrations of 1-HP and the detection calibration curve (b) of 1-HP;

[0028] Figure 6 These are the fluorescence spectrum diagram (a) of the Tb-based Ln-MOF in Example 4 of the present invention in response to different concentrations of 1-HP and the detection calibration curve (b) of 1-HP;

[0029] Figure 7 These are the response time diagrams of the Eu-based Ln-MOF (a) and Tb-based Ln-MOF (b) in Example 4 of the present invention to 1-HP;

[0030] Figure 8 These are the fluorescence detection bar graphs of the Eu-based Ln-MOF (a) and Tb-based Ln-MOF (b) in Example 4 of the present invention to 1-HP under the interference of other urine components;

[0031] Figure 9 These are the fluorescence spectrum diagrams of the Eu-based Ln-MOF (a) and Tb-based Ln-MOF (b) in Example 5 of the present invention in response to different concentrations of 1-HP in human urine. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] Example 1

[0034] A rare earth metal-organic framework is constructed from rare earth elements and the ligand 5-(1H-1,2,4-triazol-1-yl)isophthalic acid. The rare earth metal-organic framework is denoted as Ln-MOF; the chemical formula of Ln-MOF is [Ln2(5-TIA)3(H2O)3]·3H2O, where Ln represents the rare earth element Eu or Tb, and Ln exists in ionic form (Ln 3+ : Eu 3+ or Tb 3+ ), and 5-TIA is the nitrogen-containing five-membered heterocyclic ligand 5-(1H-1,2,4-triazol-1-yl)isophthalic acid. The Ln-MOF belongs to the triclinic system, space group P-1, and the unit cell parameters are α = 81.791 - 81.7970°, β = 73.849 - 74.0480°, γ = 83.0370 - 83.194°,

[0035] Example 2

[0036] A preparation method of a rare earth metal-organic framework (Ln-MOF) includes the following steps:

[0037] Put Eu(NO3)2·6H2O (44.6 mg, 0.1 mmol), 5-TIA (23.3 g, 0.1 mmol) and 13 mL of H2O into a 15 mL reaction kettle. The reaction kettle is heated to 160 °C and kept for 72 h, and then slowly cooled to room temperature. Filter, wash, and dry to obtain brown block crystals, denoted as Eu-based Ln-MOF. Based on the calculation of 5-TIA, the yield of Eu-based Ln-MOF is 85.43%.

[0038] Example 3

[0039] A preparation method of a rare earth metal-organic framework (Ln-MOF), the difference from Example 2 is only that: Eu(NO3)2·6H2O is replaced with Tb(NO3)2·6H2O (45.3 mg, 0.1 mmol), and the rest of the operations are the same as those in Example 2. Finally, brown block crystals can be obtained, denoted as Tb-based Ln-MOF. Based on the calculation of 5-TIA, the yield of Tb-based Ln-MOF is 87.21%.

[0040] The rare earth metal-organic frameworks (Ln-MOF) obtained in Examples 2 - 3 are further characterized, and the process is as follows:

[0041] (1) Single crystal structure determination of an Ln-MOF compound

[0042] Single-crystal data were collected at room temperature on a Bruker Smart APEX II CCD single-crystal diffractometer using Mo-Kα radiation monochromated by a graphite monochromator. The incident light source was used, and diffraction points were collected in the

[0043] scanning mode. Then, the data were reduced by the SAINT program. The positions of the metal atoms Ln were first determined by the direct method, and the corresponding C and N atoms were found from the difference Fourier map. The coordinates and anisotropic thermal parameters of these atoms were refined by full-matrix least-squares method. The H atoms in the ligand were obtained by geometric addition of hydrogen. All calculations were performed using the SHELXTL program package. The crystallographic data and structure refinement parameters are shown in Table 1.

[0044]

[0045]

[0046] R1 = ∑||Fo| - |Fcs|| / ∑|Fo| wR2 = ∑[w(Fo 2 - Fc 2 ) 2 / ∑[w(Fo 2 ) 2 1 / 2

[0047] The Eu-based and Tb-based Ln-MOFs obtained in Example 2 and Example 3 are isostructural. Taking the Eu-based Ln-MOF as an example, its crystal structure is described. In the crystal structure of the Eu-based Ln-MOF, its asymmetric unit structure contains 2 Eu 3+ ions, 3 5-TIA ligands, 3 coordinated water molecules and 3 free water molecules. As Figure 1 shown, Eu1 coordinates with 8 O atoms (7 O atoms come from the carboxyl groups of 5 ligands and 1 O atom comes from the coordinated water), and 1 N atom (from the triazole on the ligand); while Eu2 coordinates with 9 O atoms (7 O atoms come from the carboxyl groups of 5 ligands and 2 O atoms come from the coordinated water). As Figure 2 shown, the 5-TIA ligand has three coordination modes: μ4-η 1 :η 1 :η 1 :η 1 :η 1 :η 0 (Mode I); μ3-η 1 :η 2 :η 1 :η 1 :η 0 ​(Mode II); μ4-η 1 : η 2 : η 1 : η 1 : η 1 (Mode III). In the Eu-based Ln-MOF crystal structure, two adjacent Eu 3+ are connected by the carboxyl groups on the ligand 5-TIA to form a binuclear secondary structure unit {Ln2}. {Ln2} is further connected by the ligand 5-TIA in three different coordination modes to form a three-dimensional structure, as Figure 3 shown.

[0048] (2) Study on the solid fluorescence properties of a Ln-MOF compound

[0049] After washing and drying, the Ln-MOF crystal sample was thoroughly ground, and solid luminescence tests were carried out at room temperature, as Figure 4 shown. The Eu-based Ln-MOF exhibits strong luminescence properties under light excitation at a wavelength of 310 nm, and the emission peak is located at 628 nm; the Tb-based Ln-MOF also exhibits strong luminescence properties under light excitation at a wavelength of 293 nm, and the emission peak is located at 550 nm. It can be seen that it has potential applications in luminescent materials.

[0050] Example 4

[0051] A material for ratiometric fluorescence detection of the carcinogenic biomarker 1-HP, using the Ln-MOF prepared in Examples 2 and 3.

[0052] A detection method for ratiometric fluorescence detection of the carcinogenic biomarker 1-HP, comprising the following steps:

[0053] (1) Take 4 mg of the Ln-MOF prepared in Example 2 or Example 3 ground into powder, ultrasonically disperse it in 16 mL of DMF (N,N-dimethylformamide) for 30 min to form a suspension, and prepare a 0.25 mg / mL Ln-MOF fluorescent probe solution.

[0054] (2) Add the solution to be treated containing 1-HP to the Ln-MOF suspension, shake it well, wait for 30 s, and then use a fluorescence spectrometer to collect the fluorescence emission spectrum of the mixture at an excitation wavelength of 293 nm. And calculate the intensity ratio at 414 nm and the characteristic peak of Ln-MOF (Eu 3+ at 626 nm, Tb 3+ at 550 nm) to judge the concentration of 1-HP.

[0055] The fluorescence characteristics of the Ln-MOF fluorescent probe before and after the reaction with 1-HP were characterized by fluorescence titration experiments, and the results are as Figure 5 andFigure 6 As shown, the Eu-based Ln-MOF fluorescence probe has a strong fluorescence emission at 626 nm; the Tb-based Ln-MOF fluorescence probe has a strong fluorescence emission at 550 nm; but when continuously adding 0.001 mol / L 1-HP solution to the Ln-MOF fluorescence probe, the fluorescence intensity of the Eu-based Ln-MOF at 626 nm and the fluorescence intensity of the Tb-based Ln-MOF at 550 nm both gradually decrease with the gradual increase of the 1-HP concentration, while the fluorescence intensities at 396 nm and 414 nm gradually increase, thus constructing a ratiometric fluorescence sensor. And within a lower concentration range, the concentration of 1-HP and I 414 / I 626 or I 414 / I 550 show a linear relationship. Among them, the linear regression equation for the Eu-based Ln-MOF is I 414 / I 626 = 34.58×c(1-HP) - 0.057 (k = 3.458×10 4 M -1 ), the R 2 value is 0.995, and the lowest detection limit is 1.04 μmol / L; for the Tb-based Ln-MOF, the equation is I 414 / I 550 = 31.48×c(1-HP) - 0.0213 (k = 3.148×10 4 M -1 ), the R 2 value is 0.999, and the detection limit is 4.5 μmol / L.

[0056] Figure 7 For the Ln-MOF fluorescence probe after adding 0.001 mol / L 1-HP, the graph of the intensity ratio (I 414 / I 626 or I 414 / I 550 ) changing with time. It can be seen from the graph that after adding 1-HP for 30 s, the intensity ratio basically remains unchanged, indicating that the detection of 1-HP by the Ln-MOF fluorescence probe can be completed within 30 s.

[0057] Investigate the detection of 1-HP by the Ln-MOF compound under the interference of other urine components. Such as Figure 8As shown, the response intensity of the Ln-MOF fluorescent probe to 0.001 mol / L 1-HP is much higher than that of other urine components (such as KCl, NaCl, NH4Cl, uric acid, hippuric acid, sarcosine, creatinine, urea, glucose), indicating that these urine components do not affect the detection of 1-HP, and indicating that the Ln-MOF fluorescent probe prepared by the present invention has good selectivity and anti-interference for the detection of 1-HP.

[0058] Example 5

[0059] A method for detecting the carcinogenic biomarker 1-HP in urine by ratio fluorescence detection, comprising the following steps:

[0060] (1) Take 4 mg of the Ln-MOF prepared in Example 2 or Example 3 ground into powder and ultrasonically disperse it in 16 mL of DMF (N,N-dimethylformamide) for 30 min to form a suspension, and prepare a 0.25 mg / mL Ln-MOF fluorescent probe solution.

[0061] (2) Add the solution to be treated with 1-HP prepared by mixing urine and DMF into the Ln-MOF suspension, shake well, wait for 30 s, and then use a fluorescence spectrometer to collect the fluorescence emission spectrum of the mixture when the excitation wavelength is 293 nm. And calculate the intensity ratio at 414 nm and the characteristic peak of Ln-MOF (Eu 3+ at 626 nm, Tb 3+ at 550 nm) to judge the concentration of 1-HP.

[0062] The fluorescence characteristics of the Ln-MOF fluorescent probe before and after its interaction with 1-HP were characterized by fluorescence titration experiments, and the results are as Figure 9As shown, the Eu-based Ln-MOF fluorescent probe has a strong fluorescence emission at 626 nm; the Tb-based Ln-MOF fluorescent probe has a strong fluorescence emission at 550 nm. However, when continuously adding 0.001 mol / L of 1-HP solution to the Ln-MOF fluorescent probe, the fluorescence intensity of the Eu-based Ln-MOF at 626 nm and the fluorescence intensity of the Tb-based Ln-MOF at 550 nm both gradually decrease with the gradual increase of the 1-HP concentration, while the fluorescence intensities at 396 nm and 414 nm gradually increase, thus constructing a ratiometric fluorescence sensor. By measuring the fluorescence spectra of actual samples and comparing them with the fluorescence spectra of standard samples, the recovery rate is calculated. Obviously, both the Eu-based and Tb-based Ln-MOFs have high recovery rates. As shown in Tables 2 and 3, a series of human urine samples containing different concentrations of 1-HP were obtained, and their recovery rates were calculated. Among them, the recovery rate of the Eu-based Ln-MOF was 98.79% - 103.47%, and the recovery rate of the Tb-based Ln-MOF was 100.90% - 102.02%. Through actual parallel experiments, the relative standard deviation (RSD) of the Eu-based Ln-MOF was less than 1%, and the RSD of the Tb-based Ln-MOF was less than 5%. The above results indicate that the Ln-MOF fluorescent probe has a good detection effect on 1-HP in actual urine samples.

[0063] Table 2 Detection of 1-HP in Human Urine by Eu-based Ln-MOF

[0064]

[0065] Table 3 Detection of 1-HP in Human Urine by Tb-based Ln-MOF

[0066]

[0067] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements or use similar methods to replace the specific embodiments described, as long as they do not deviate from the structure of the present invention or exceed the scope defined by this claim book, they should all belong to the protection scope of the present invention.

Claims

1. A rare earth-based metal-organic framework, characterized in that: The chemical formula is [Ln2(5-TIA)3(H2O)3]·3H2O, wherein Ln represents the rare earth element Eu or Tb, Ln exists in ionic form, and 5-TIA is a nitrogen-containing five-membered heterocyclic ligand 5-(1H-1,2,4-triazol-1-yl)isophthalic acid.

2. A method for preparing a rare earth metal-organic framework according to claim 1, characterized in that: The following steps are involved: Under hydrothermal conditions, rare earth salt, ligand 5-(1H-1,2,4-triazole-1-yl)isophthalic acid and water are added to a reaction kettle, and the reaction is carried out at 140-160° C. for 24-72 hours. After the reaction is completed, it is naturally cooled to room temperature, filtered, washed, and dried to obtain crystals, which are the rare earth-based metal-organic framework.

3. The method for preparing a rare earth metal-organic framework according to claim 2, characterized in that: The rare earth salt is at least one of rare earth nitrate and rare earth chloride.

4. The method for preparing a rare earth metal-organic framework according to claim 2, characterized in that: The molar ratio of the rare earth salt, 5-(1H-1,2,4-triazol-1-yl)isophthalic acid and water is (0.8-1.5):1:(500-833).

5. A ratio fluorescence detection material for the carcinogenic marker 1-hydroxypyrene, characterized in that: The material comprises the rare earth-based metal-organic framework according to claim 1.

6. A ratio fluorescence detection method for the carcinogenic marker 1-hydroxypyrene, characterized in that: The method comprises the following steps: ultrasonically dispersing the rare earth-based metal-organic framework described in claim 1 in an N,N-dimethylformamide solution to obtain a suspension, adding a solution to be treated containing 1-hydroxypyrene into the suspension and shaking it evenly, waiting for 30-240 seconds, collecting a fluorescence emission spectrum of the mixed solution at an excitation wavelength of 293 nm using a fluorescence spectrometer, and calculating the ratio of the intensity at 414 nm to the characteristic peak of the rare earth-based metal-organic framework to determine the concentration of 1-hydroxypyrene.

7. The ratio fluorescence detection method of the carcinogenic marker 1-hydroxypyrene according to claim 6, characterized in that: The concentration of the suspension is 0.25-1.0 mg / mL.

8. The ratio fluorescence detection method of the carcinogenic marker 1-hydroxypyrene according to claim 6, characterized in that: The concentration range of 1-hydroxypyrene in the solution to be treated is 0-52 μmol / L.

9. A method for detecting the carcinogenic marker 1-hydroxypyrene in urine, characterized in that: The detection is performed using the ratio fluorescence detection method for the carcinogenic marker 1-hydroxypyrene described in claim 6.

10. A luminescent material, characterized in that: It comprises the rare earth-based metal-organic framework as claimed in claim 1.

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