A terbium-europium bimetallic organic framework fluorescent probe, a preparation method and application thereof

Abstract

The application relates to the technical field of metal organic framework-based luminescent materials, and discloses a terbium-europium bimetallic organic framework fluorescent probe as well as a preparation method and application thereof, the chemical formula of the fluorescent probe is (H3O)[Eu 0.3 Tb 0.7 (L)2(H2O)4], wherein L 2‑ is obtained by in-situ hydrolysis of 2,4,6-tri(4-carboxyphenoxy)-1,3,5-triazine. The preparation method comprises the following steps: mixing an europium salt, a terbium salt, 2,4,6-tri(4-carboxyphenoxy)-1,3,5-triazine, acetonitrile and water, and reacting at 80-100 DEG C for 24-72 h. The fluorescent probe can be used for detecting 5-hydroxyindole-3-acetic acid, and the detection is realized based on the fluorescence intensity changes of three emission wavelengths of 334 nm, 544 nm and 618 nm, and the fluorescent probe has the characteristics of wide detection range, strong anti-interference ability and short detection time.

Description

Technical Field

[0001] This invention relates to the field of metal-organic framework-based luminescent materials, and particularly to a terbium-europium bimetallic organic framework fluorescent probe, its preparation method, and its application. Background Technology

[0002] In recent years, the detection of biomarkers has become increasingly important in health risk assessment, early disease diagnosis, and treatment monitoring. Specific identification and high-sensitivity detection of biomarkers in plasma and urine are crucial for health risk assessment, early disease diagnosis, and prevention. Serotonin (5-hydroxytryptamine) is an inhibitory neurotransmitter in the central nervous system; abnormal levels may be associated with diseases such as carcinoid tumors, schizophrenia, migraines, anxiety disorders, and Alzheimer's disease. 5-Hydroxyindole-3-acetic acid (5-HA) is an endogenous metabolite of serotonin, and abnormal levels can be detected in the urine of patients with carcinoid tumors. Therefore, 5-HA is commonly used as a representative biomarker for the diagnosis of carcinoid tumors.

[0003] Currently, methods for detecting 5-hydroxyindole-3-acetic acid mainly include electrochemical analysis, liquid chromatography-mass spectrometry (LC-MS), and liquid chromatography-luminescence spectrometry (LC-MS). However, these methods generally suffer from high instrument costs, complex operation, low analytical efficiency, and the toxicity of some reagents. Furthermore, in complex biological systems, coexisting neurotransmitters such as glutamate and aspartate may interfere with the detection process, affecting selectivity and thus limiting the practical application of these methods in complex biological samples. Therefore, developing a simple, rapid, and highly selective method for detecting 5-hydroxyindole-3-acetic acid is of great significance.

[0004] Luminescent metal-organic frameworks (MOFs) have been used for the detection of targets such as ions, volatile organic compounds, antibiotics, and biomarkers due to their optical tunability and fluorescence diversity. Among them, lanthanide MOFs, with their narrow emission peaks, large Stokes shifts, long fluorescence lifetimes, and high quantum yields, show promising applications in fluorescence sensing. However, most reported lanthanide MOF fluorescence sensors currently rely on the intensity change of a single emission signal for detection, making them susceptible to interference from external environmental factors, which can affect their sensitivity, selectivity, and anti-interference capabilities.

[0005] Studies have shown that constructing multi-emission lanthanide metal-organic framework (MOF) fluorescent sensors with dual or triple emission characteristics can achieve signal self-calibration by monitoring changes in the intensity ratio between multiple emission peaks, thereby reducing the influence of external environmental factors on the detection results and improving the accuracy and reliability of detection. While there are a few reports on the detection of 5-hydroxyindole-3-acetic acid (5-HA) based on dual-emission ratio-type MOF materials, the detection of 5-HA using triple-emission MOF fluorescent sensors still requires further investigation. Therefore, it is necessary to provide a multi-emission fluorescent detection material and method capable of sensitive and selective detection of 5-HA. Summary of the Invention

[0006] The purpose of this invention is to provide a terbium-europium bimetallic organic framework fluorescent probe, its preparation method and application, so as to achieve fluorescence detection of 5-hydroxyindole-3-acetic acid.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A terbium-europium bimetallic organic framework fluorescent probe, the chemical formula of which is (H3O)[Eu] 0.3 Tb 0.7 [(L)2(H2O)4], abbreviated as Eu 0.3 Tb 0.7 -MOF. Where L 2- The L is a 4-(4,6-dihydroxy-1,3,5-triazine-2-oxy)benzoic acid ligand. 2- It is obtained by in-situ hydrolysis of 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine.

[0009] A method for preparing a terbium-europium bimetallic organic framework fluorescent probe as described above includes the following steps:

[0010] Europium salt, terbium salt, 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine, acetonitrile and water were mixed and reacted at 80~100℃ for 24~72 h. After the reaction was completed, the mixture was cooled to room temperature and then filtered, washed and dried to obtain the terbium-europium bimetallic organic framework fluorescent probe.

[0011] Preferably, both europium salt and terbium salt are nitrates, the total molar amount of europium salt and terbium salt is 0.05 mmol, and the molar ratio of europium salt to terbium salt is 3:7.

[0012] Preferably, the volume ratio of acetonitrile to water is (5~7):1.

[0013] The above-mentioned terbium-europium bimetallic organic framework fluorescent probe is used in the detection of 5-hydroxyindole-3-acetic acid.

[0014] A fluorescent detection material comprising the aforementioned terbium-europium bimetallic organic framework fluorescent probe, wherein the fluorescent detection material is used to detect 5-hydroxyindole-3-acetic acid.

[0015] A fluorescence detection method for 5-hydroxyindole-3-acetic acid using the above-mentioned terbium-europium bimetallic organic framework fluorescent probe includes the following steps:

[0016] The crystalline material of the terbium-europium bimetallic organic framework fluorescent probe was dispersed in ethanol to obtain a fluorescent probe suspension.

[0017] The solution containing the analyte is added to the fluorescent probe suspension and mixed well to obtain a mixture;

[0018] The fluorescence emission spectrum of the mixture was collected using a fluorescence spectrometer, and 5-hydroxyindole-3-acetic acid was detected based on the fluorescence emission spectrum.

[0019] Preferably, the concentration of the terbium-europium bimetallic organic framework fluorescent probe in the fluorescent probe suspension is 0.2~0.5 mg / mL.

[0020] Preferably, at an excitation wavelength of 286 nm, the fluorescence intensities at 334 nm, 544 nm, and 618 nm are denoted as I0. 334 I 544 and I 618 Before adding the solution containing the analyte, I 334 / I 544 / I 618 As the initial fluorescence intensity ratio (I 334 / I 544 / I 618 0, based on the fluorescence intensity ratio I after adding the solution containing the analyte. 334 / I 544 / I 618 The ratio of the initial fluorescence intensity (I) 334 / I 544 / I 618 The ratio of 0 to 0 determines the concentration of 5-hydroxyindole-3-acetic acid.

[0021] Among them I 334 / I 544 / I 618 The calculation relationship is: the fluorescence intensity at 334 nm divided by the fluorescence intensity at 544 nm, and then divided by the fluorescence intensity at 618 nm.

[0022] Preferably, the concentration of 5-hydroxyindole-3-acetic acid in the solution containing the analyte is in the range of 0~196 μmol / L.

[0023] The beneficial effects of this invention are as follows:

[0024] The terbium-europium bimetallic organic framework fluorescent probe provided by this invention can be used to detect 5-hydroxyindole-3-acetic acid, constructing a three-emission Ln-MOF fluorescent sensor for the detection of 5-hydroxyindole-3-acetic acid. When emitted into Eu... 0.3 Tb 0.7 After adding 5-hydroxyindole-3-acetic acid to the MOF suspension, Eu 0.3 Tb 0.7 The fluorescence intensity of the -MOF decreases at 618 nm and 544 nm, while the fluorescence intensity increases at 334 nm, thereby forming a three-emission fluorescence response to 5-hydroxyindole-3-acetic acid, indicating that the terbium-europium bimetallic organic framework fluorescent probe has good application potential in the detection of 5-hydroxyindole-3-acetic acid.

[0025] The terbium-europium bimetallic organic framework fluorescent probe provided by this invention has a detection limit as low as 2.65 nmol / L and a detection concentration range of 0~196 μmol / L when used for the detection of 5-hydroxyindole-3-acetic acid. At the same time, it can selectively detect 5-hydroxyindole-3-acetic acid even in the presence of other urine components, has good anti-interference ability, and has the characteristics of short detection time. Attached Figure Description

[0026] Figure 1 This is the fluorescence spectrum of the terbium-europium bimetallic organic framework fluorescent probe in Application Example 2 of the present invention in response to different concentrations of 5-hydroxyindole-3-acetic acid.

[0027] Figure 2 It is the ratio of the fluorescence intensity of the 5-hydroxyindole-3-acetic acid concentration in the range of 0~196 μmol / L to that of the terbium-europium bimetallic organic framework fluorescent probe in Application Example 2 of this invention (I 334 / I 544 / I 618 ) / (I 334 / I 544 / I 618 The graph shows the relationship between 5-hydroxyindole-3-acetic acid concentration in the range of 0 to 35 μmol / L and the fluorescence intensity ratio, with the inset showing a linear relationship between the concentration of 5-hydroxyindole-3-acetic acid and the fluorescence intensity ratio.

[0028] Figure 3 This is the fluorescence emission spectrum of the terbium-europium bimetallic organic framework fluorescent probe for 5-hydroxyindole-3-acetic acid and other urine components in Application Example 2 of this invention.

[0029] Figure 4This is a bar chart showing the fluorescence detection of 5-hydroxyindole-3-acetic acid by a terbium-europium bimetallic organic framework fluorescent probe in Application Example 2 of this invention, under the interference of other urine components.

[0030] Figure 5 This is a fluorescence response time diagram of the terbium-europium bimetallic organic framework fluorescent probe to 5-hydroxyindole-3-acetic acid in Application Example 2 of this invention.

[0031] Figure 6 This refers to the fluorescence intensity ratio (I) of the terbium-europium bimetallic organic framework fluorescent probe in Application Example 2 of this invention during 5 cycles of detection of 5-hydroxyindole-3-acetic acid. 334 / I 544 / I 618 ) / (I 334 / I 544 / I 618 The graph showing the change of 0.

[0032] Figure 7 This is the solid-state fluorescence spectrum of the terbium-europium bimetallic organic framework fluorescent probe in Application Example 3 of this invention.

[0033] Figure 8 Eu in Embodiment 3 of the present invention 0.3 Tb 0.7 PXRD comparison chart of MOF with simulation, Eu-MOF and Tb-MOF.

[0034] Figure 9 Eu in Embodiment 3 of the present invention 3+ and Tb 3+ Eu doped in different proportions x Tb 1-x Solid-state fluorescence emission spectra of -MOF, pure-phase Eu-MOF, and Tb-MOF at an excitation wavelength of 286 nm. Detailed Implementation

[0035] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0036] In one embodiment, the present invention provides a terbium-europium bimetallic organic framework fluorescent probe, the chemical formula of which is (H3O)[Eu] 0.3 Tb 0.7 [(L)2(H2O)4], abbreviated as Eu 0.3 Tb 0.7 -MOF. Where L 2- The L is a 4-(4,6-dihydroxy-1,3,5-triazine-2-oxy)benzoic acid ligand. 2-It is obtained by in-situ hydrolysis of 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine.

[0037] In one embodiment, the present invention provides a method for preparing a terbium-europium bimetallic organic framework fluorescent probe as described above, comprising the following steps:

[0038] Europium salt, terbium salt, 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine, acetonitrile and water were mixed and reacted at 80~100℃ for 24~72 h. After the reaction was completed, the mixture was cooled to room temperature and then filtered, washed and dried to obtain the terbium-europium bimetallic organic framework fluorescent probe.

[0039] The terbium-europium bimetallic organic framework fluorescent probe is a crystalline material.

[0040] In a preferred embodiment of the present invention, both europium salt and terbium salt are nitrates, the total molar amount of europium salt and terbium salt is 0.05 mmol, and the molar ratio of europium salt to terbium salt is 3:7.

[0041] In a preferred embodiment of the present invention, the volume ratio of acetonitrile to water is (5~7):1.

[0042] In one embodiment, the present invention proposes the application of the above-described terbium-europium bimetallic organic framework fluorescent probe in the detection of 5-hydroxyindole-3-acetic acid.

[0043] In one embodiment, the present invention provides a fluorescent detection material comprising the above-described terbium-europium bimetallic organic framework fluorescent probe, wherein the fluorescent detection material is used to detect 5-hydroxyindole-3-acetic acid.

[0044] In one embodiment, the present invention provides a fluorescence detection method for 5-hydroxyindole-3-acetic acid using the above-described terbium-euphrates bimetallic organic framework fluorescent probe, comprising the following steps:

[0045] The crystalline material of the terbium-europium bimetallic organic framework fluorescent probe was dispersed in ethanol to obtain a fluorescent probe suspension.

[0046] The solution containing the analyte is added to the fluorescent probe suspension and mixed well to obtain a mixture;

[0047] The fluorescence emission spectrum of the mixture was collected using a fluorescence spectrometer, and 5-hydroxyindole-3-acetic acid was detected based on the fluorescence emission spectrum.

[0048] In a preferred embodiment of the present invention, the concentration of the terbium-europium bimetallic organic framework fluorescent probe in the fluorescent probe suspension is 0.2~0.5 mg / mL.

[0049] In a preferred embodiment of the present invention, at an excitation wavelength of 286 nm, the fluorescence intensities at 334 nm, 544 nm, and 618 nm are denoted as I, respectively. 334 I 544 and I 618 Before adding the solution containing the analyte, I 334 / I 544 / I 618 As the initial fluorescence intensity ratio (I 334 / I 544 / I 618 0, based on the fluorescence intensity ratio I after adding the solution containing the analyte. 334 / I 544 / I 618 The ratio of the initial fluorescence intensity (I) 334 / I 544 / I 618 The ratio of 0 to 1 determines the concentration of 5-hydroxyindole-3-acetic acid. Where I 334 / I 544 / I 618 The calculation relationship is: the fluorescence intensity at 334 nm divided by the fluorescence intensity at 544 nm, and then divided by the fluorescence intensity at 618 nm.

[0050] In a preferred embodiment of the present invention, the concentration range of 5-hydroxyindole-3-acetic acid in the solution containing the analyte is 0~196 μmol / L.

[0051] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0052] Example 1: A terbium-europium bimetallic organic framework fluorescent probe, wherein the chemical formula of the fluorescent probe is (H3O)[Eu] 0.3 Tb 0.7 [(L)2(H2O)4], abbreviated as Eu 0.3 Tb 0.7 -MOF. Where L 2- The L is a 4-(4,6-dihydroxy-1,3,5-triazine-2-oxy)benzoic acid ligand. 2- It is obtained by in-situ hydrolysis of 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine.

[0053] Example 2: A method for preparing the terbium-europium bimetallic organic framework fluorescent probe described in Example 1, comprising the following steps:

[0054] Europium nitrate hexahydrate 6.7 mg (0.015 mmol), terbium nitrate hexahydrate 15.9 mg (0.035 mmol) and 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine 25 mg (0.05 mmol) were added to a 15 mL high-pressure reactor, followed by the addition of 1 mL of distilled water and 5 mL of acetonitrile. The mixture was heated to 90 °C and reacted for 72 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and washed three times with distilled water. The mixture was then dried at room temperature to obtain yellow rhomboid crystals, which were the terbium-europium bimetallic organic framework fluorescent probe.

[0055] Example 3: This example applies to Eu 0.3 Tb 0.7 The structure of -MOF was characterized.

[0056] The crystal structure data and refinement parameters of Eu-MOF and Tb-MOF were obtained, as shown in Table 1. The chemical formula of the terbium-europium bimetallic organic framework fluorescent probe described in this embodiment is (H3O)[Eu] 0.3 Tb 0.7 [(L)2(H2O)4], abbreviated as Eu 0.3 Tb 0.7 -MOF. Eu 0.3 Tb 0.7 The synthesis steps of -MOF are similar to those of Eu-MOF and Tb-MOF, the difference being that Eu-MOF is prepared using a different method. 0.3 Tb 0.7 At -MOF, the total number of moles of europium and terbium salts is 0.05 mmol, and the molar ratio of europium to terbium salt is 3:7.

[0057] Table 1 Crystal structure data and refinement parameters of Eu-MOF and Tb-MOF

[0058] Compounds Eu-MOF Tb-MOF Molecular formula <![CDATA[C 20 H 26 EuN6O 16 ]]> <![CDATA[C 20 H 26 N6O 16 Tb]]> molecular weight 758.43 765.40 Crystal system Monoclinic Monoclinic Space Group C2 / c C2 / c a （Å） 19.6280（2） 19.5634（6） b （Å） 8.43300（10） 8.3955（2） c （Å） 16.0919（2） 16.1534（4） β （°） 99.5160（10） 99.9610（10） <![CDATA[V (Å 3 )]]> 2626.93（5） 2613.11（12） Z 4 4 F（000） 1516 1524 θ range (°) 2.104-24.988 2.560 - 27.608 Limiting factors -23<=h<=23, -5<=k<=10, -19<=l<=13 -22<=h<=25, -9<=k<=10, -20<=l<=20 <![CDATA[Total / unique diffraction points (R int )]]> 8085 / 2254 （ 0.0697） 8520 / 2872 （0.0158） <![CDATA[Theoretical density (g·cm -3 )]]> 1.918 1.946 <![CDATA[absorption coefficient (mm -1 )]]> 2.480 2.799 Data / Limitations / Parameters 2254 / 12 / 213 2872 / 0 / 213 GOOF value 1.033 1.112 R factor [I>2σ(I)] 0.0369, 0.1044 0.0168, 0.0436 R factor (all data) 0.0375, 0.1048 0.0173, 0.0438 <![CDATA[Maximum diffraction peaks and valleys (e Å -3 )]]> 0.677, -0.851 0.444, -0.829

[0059] Eu 0.3 Tb 0.7 The structure of -MOF was determined by comparing it with that of Eu-MOF and Tb-MOF using PXRD. 0.3 Tb 0.7 The PXRD comparison results of -MOF with simulation, Eu-MOF and Tb-MOF are as follows: Figure 8 As shown. By Figure 8 It can be seen that Eu 0.3 Tb 0.7 -MOF exhibits consistent PXRD patterns with Eu-MOF and Tb-MOF, thus determining Eu 0.3 Tb 0.7 -The structure of MOF.

[0060] Further research on Eu3+ and Tb 3+ Eu doped in different proportions x Tb 1-x Solid-state fluorescence emission spectroscopy was performed on Eu-MOF, pure-phase Eu-MOF, and Tb-MOF. At an excitation wavelength of 286 nm, Eu-MOFs with different doping ratios were analyzed. x Tb 1-x -MOFs exhibit different solid-state fluorescence emission intensities, specifically as follows: Figure 9 As shown in the figure, the emission intensity of both Eu and Tb is highest when the ratio of Eu to Tb is 0.3:0.7.

[0061] The following application examples illustrate the use of the terbium-europium bimetallic organic framework fluorescent probe prepared in Example 2 in the detection of 5-hydroxyindole-3-acetic acid and in luminescent materials.

[0062] Application Example 1: A fluorescent detection material, using the terbium-euphrates bimetallic organic framework fluorescent probe prepared in Example 2 as the detection material, is used to detect 5-hydroxyindole-3-acetic acid.

[0063] Application Example 2: A fluorescence detection method for 5-hydroxyindole-3-acetic acid, comprising the following steps.

[0064] (1) Take 1 mg of the terbium-europium bimetallic organic framework fluorescent probe prepared in Example 2 and grind it into powder. Disperse it in 4 mL of ethanol by sonication and sonicate it for 30 min to form a fluorescent probe suspension. The concentration of the terbium-europium bimetallic organic framework fluorescent probe in the fluorescent probe suspension is 0.25 mg / mL.

[0065] (2) Take 2 mL of fluorescent probe suspension with a concentration of 0.25 mg / mL and gradually add 5-hydroxyindole-3-acetic acid aqueous solution with a concentration of 0.01 mol / L to it. That is, add different volumes of the 5-hydroxyindole-3-acetic acid aqueous solution in batches. Measure the fluorescence emission spectrum once each time it is added to obtain the fluorescence emission spectrum at different concentrations of 5-hydroxyindole-3-acetic acid.

[0066] At an excitation wavelength of 286 nm, the fluorescence intensities at 334 nm, 544 nm, and 618 nm are denoted as I, respectively. 334 I 544 and I 618 Before adding the solution containing the analyte, I 334 / I 544 / I 618 As the initial fluorescence intensity ratio (I 334 / I 544 / I 6180, based on the fluorescence intensity ratio I after adding the solution containing the analyte. 334 / I 544 / I 618 The ratio of the initial fluorescence intensity (I) 334 / I 544 / I 618 The ratio of 0 to 0 determines the concentration of 5-hydroxyindole-3-acetic acid.

[0067] like Figure 1 As shown, with the gradual addition of 5-hydroxyindole-3-acetic acid, Eu 0.3 Tb 0.7 - The fluorescence intensity of the MOF gradually decreases at 544 nm and 618 nm, while the fluorescence intensity gradually increases at 334 nm, forming a three-emission fluorescence sensing response.

[0068] like Figure 2 As shown, Eu 0.3 Tb 0.7 -MOF fluorescence intensity ratio (I 334 / I 544 / I 618 ) / (I 334 / I 544 / I 618 )0, where I 334 / I 544 / I 618 The operational relationship is as follows: the fluorescence intensity at 334 nm is divided by the fluorescence intensity at 544 nm, and then divided by the fluorescence intensity at 618 nm. Within the concentration range of 0–196 μmol / L, this relationship exhibits a non-linear functional relationship with the concentration of 5-hydroxyindole-3-acetic acid, and the equation is:

[0069] (I 334 / I 544 / I 618 ) / (I 334 / I 544 / I 618 )0 = 247.78×exp(0.014×c(5-hydroxyindole-3-acetic acid))-246.78,

[0070] Among them, R 2 = 0.998, indicating that 5-hydroxyindole-3-acetic acid can be determined in the concentration range of 0~196 μmol / L.

[0071] Within a low concentration range, specifically when the concentration of 5-hydroxyindole-3-acetic acid is 0–35 μmol / L, the above fluorescence intensity ratio exhibits a good linear relationship with the concentration of 5-hydroxyindole-3-acetic acid, as shown in the following equation:

[0072] (I 334 / I 544 / I 618 ) / (I 334 / I 544 / I 618 )0 = 4.03 × c(5-hydroxyindole-3-acetic acid) + 1,

[0073] Among them, R 2 = 0.996, K sv = 4.03×10 6 Based on L / mol and 3σ / k, the detection limit (LOD) is 2.65 nmol / L, indicating that the terbium-europium bimetallic organic framework fluorescent probe prepared in Example 2 has high detection sensitivity for 5-hydroxyindole-3-acetic acid.

[0074] The selective detection performance of the terbium-europium bimetallic organic framework fluorescent probe prepared in Example 2 for 5-hydroxyindole-3-acetic acid was further investigated. 5-hydroxyindole-3-acetic acid and the main components of human urine, namely NaCl, KCl, NH4Cl, uric acid, urea, creatinine, glucose, and sarcosine, were added to 2 mL of a 0.25 mg / mL fluorescent probe suspension, and the fluorescence emission spectrum was recorded at an excitation wavelength of 286 nm.

[0075] like Figure 3 As shown, when the other urine components mentioned above were added, the fluorescence emission spectrum remained essentially unchanged; however, when 5-hydroxyindole-3-acetic acid was added, the Eu... 0.3 Tb 0.7 -MOFs exhibit a significant three-emission fluorescence response.

[0076] The detection capability of the terbium-europium bimetallic organic framework fluorescent probe prepared in Example 2 for 5-hydroxyindole-3-acetic acid under interference from other urine components was further investigated. Figure 4 As shown, when other urine components are present, Eu 0.3 Tb 0.7 -MOF fluorescence intensity change ratio (I 334 / I 544 / I 618 ) / (I 334 / I 544 / I 618 The value of 0 was still significantly higher than the blank value when 5-hydroxyindole-3-acetic acid was not added, indicating that the interference of the above-mentioned common urinary coexisting substances on the detection of 5-hydroxyindole-3-acetic acid by the terbium-europium bimetallic organic framework fluorescent probe is negligible, and the terbium-europium bimetallic organic framework fluorescent probe has good anti-interference ability.

[0077] The fluorescence response time of the terbium-europium bimetallic organic framework fluorescent probe prepared in Example 2 to 5-hydroxyindole-3-acetic acid was further investigated. Figure 5 As shown, after adding 5-hydroxyindole-3-acetic acid to the detection system, the ratio of the original fluorescence intensity at emission wavelengths of 334 nm, 544 nm, and 618 nm is I. 334 / I 544 / I 618 The response time decreased rapidly within 30 s and reached a stable value, and remained essentially constant for the next 300 s, indicating that the terbium-europium bimetallic organic framework fluorescent probe has a rapid response characteristic to 5-hydroxyindole-3-acetic acid, with a response time of 30 s.

[0078] The cyclic performance of the terbium-europium bimetallic organic framework fluorescent probe prepared in Example 2 for the detection of 5-hydroxyindole-3-acetic acid was further investigated. Figure 6 As shown, after 5 cycles of detection, the ratio of fluorescence intensity change (I) 334 / I 544 / I 618 ) / (I 334 / I 544 / I 618 The changes in 0 are all within a reasonable range, indicating that the terbium-europium bimetallic organic framework fluorescent probe can maintain stable fluorescence response performance during 5 cycles of detection and has good reusability.

[0079] After each detection, the terbium-europium bimetallic organic framework fluorescent probe was washed with ethanol and centrifuged three times. The resulting solid was then dried and reconstituted into a fluorescent probe suspension with a concentration of 0.25 mg / mL. The fluorescence emission spectrum of the regenerated fluorescent probe suspension showed recovery at 544 nm and 618 nm, and the absence of an emission peak for 5-hydroxyindole-3-acetic acid at 334 nm, indicating that the terbium-europium bimetallic organic framework fluorescent probe can be regenerated and recycled.

[0080] Application Example 3: A luminescent material, comprising the terbium-euphrates bimetallic organic framework fluorescent probe prepared in Example 2.

[0081] The terbium-europium bimetallic organic framework fluorescent probe crystal sample prepared in Example 2 was thoroughly ground and subjected to solid-state luminescence testing at room temperature. Figure 7 As shown, when the excitation wavelength is set to 286 nm, Eu 0.3 Tb 0.7 -MOF exhibits Eu at 618 nm 3+ of 5 D0→ 7F2 characteristic emission, exhibiting Tb at 544 nm 3+ of 5 D4→ 7 F5 characteristic emission indicates Eu 3+ and Tb 3+ With successful doping, the terbium-europium bimetallic organic framework fluorescent probe has potential applications in luminescent materials.

[0082] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A terbium-europium bimetallic organic framework fluorescent probe, characterized in that, The chemical formula of the fluorescent probe is (H3O)[Eu] 0.3 Tb 0.7 [(L)2(H2O)4], where L 2- The L is a 4-(4,6-dihydroxy-1,3,5-triazine-2-oxy)benzoic acid ligand. 2- It is obtained by in-situ hydrolysis of 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine.

2. A method for preparing a terbium-europium bimetallic organic framework fluorescent probe as described in claim 1, characterized in that, Includes the following steps: Europium salt, terbium salt, 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine, acetonitrile and water were mixed and reacted at 80-100 °C for 24-72 h. After the reaction was completed, the mixture was cooled to room temperature and then filtered, washed and dried to obtain the terbium-europium bimetallic organic framework fluorescent probe.

3. The preparation method according to claim 2, characterized in that, Both europium salt and terbium salt are nitrates, and the molar ratio of europium salt to terbium salt is 3:

7.

4. The preparation method according to claim 2, characterized in that, The volume ratio of acetonitrile to water is (5~7):

1.

5. The application of the terbium-europium bimetallic organic framework fluorescent probe of claim 1 in the detection of 5-hydroxyindole-3-acetic acid.

6. A fluorescent detection material, characterized in that, The fluorescent probe comprising the terbium-europium bimetallic organic framework of claim 1, wherein the fluorescent detection material is used to detect 5-hydroxyindole-3-acetic acid.

7. A fluorescence detection method for 5-hydroxyindole-3-acetic acid using the terbium-euphrates bimetallic organic framework fluorescent probe according to claim 1, characterized in that, Includes the following steps: The crystalline material of the terbium-europium bimetallic organic framework fluorescent probe was dispersed in ethanol to obtain a fluorescent probe suspension. The solution containing the analyte is added to the fluorescent probe suspension and mixed well to obtain a mixture; The fluorescence emission spectrum of the mixture was collected using a fluorescence spectrometer, and 5-hydroxyindole-3-acetic acid was detected based on the fluorescence emission spectrum.

8. The fluorescence detection method according to claim 7, characterized in that, The concentration of the terbium-europium bimetallic organic framework fluorescent probe in the fluorescent probe suspension is 0.2~0.5 mg / mL.

9. The fluorescence detection method according to claim 7, characterized in that, At an excitation wavelength of 286 nm, the fluorescence intensities at 334 nm, 544 nm, and 618 nm are denoted as I, respectively. 334 I 544 and I 618 Before adding the solution containing the analyte, I 334 / I 544 / I 618 As the initial fluorescence intensity ratio (I 334 / I 544 / I 618 0, based on the fluorescence intensity ratio I after adding the solution containing the analyte. 334 / I 544 / I 618 The ratio of the initial fluorescence intensity (I) 334 / I 544 / I 618 The ratio of 0 to 0 determines the concentration of 5-hydroxyindole-3-acetic acid.

10. The fluorescence detection method according to claim 9, characterized in that, The concentration range of 5-hydroxyindole-3-acetic acid in the solution containing the analyte is 0~196 μmol / L.

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