A cadmium-based metal-organic framework material for fluorescence detection of lysine, its preparation method and application

Abstract

This invention relates to a cadmium-based metal-organic framework material for the fluorescence detection of lysine, its preparation method, and its application. The preparation method comprises: Step 1, dissolving a cadmium source, an organic carboxylic acid ligand, and a nitrogen-containing auxiliary ligand in a mixed solvent composed of deionized water and an organic solvent to obtain a mixed solution; Step 2, stirring the mixed solution at room temperature, reacting it in a reaction vessel, cooling the reactants, washing, and drying to obtain the cadmium-based metal-organic framework material for the fluorescence detection of lysine. The material prepared by this invention exhibits high selective recognition ability for lysine, enabling highly sensitive and rapid quantitative detection of lysine in aqueous systems and simulated human urine systems.

Description

Technical Field

[0001] This invention belongs to the field of biomaterial sensing technology, specifically relating to a cadmium-based metal-organic framework material for fluorescence detection of lysine, its preparation method, and its application. Background Technology

[0002] Metal-organic frameworks (MOFs), assembled from various metal ions / clusters and organic ligands, have recently emerged as promising materials, providing a potential platform for their wide application in fields such as chemical sensing, gas separation, magnetism, and food safety. In the context of sensing-based applications, the structural diversity and tunable luminescence properties of MOFs make them one of the best candidate materials for highly efficient fluorescent sensors. In recent years, luminescent metal-organic frameworks (LMOFs) have been extensively studied as sensors for the efficient detection of various substances, including ions, small organic molecules, nitro explosives, and biomolecules. In particular, LMOFs have shown great potential in detecting biomarkers, DNA, and amino acids directly related to human health and normal growth.

[0003] Lysine, one of the eight essential amino acids (AAs), plays a crucial role in the Krebs-Henseleit cycle and polyamine synthesis, making it an essential nutrient for the human body. However, the synthesis of lysine in the human body is incomplete, thus lysine must be supplied externally. Therefore, lysine content is an important indicator of the nutritional value of food, and developing a rapid, accurate, and sensitive method for lysine detection is of great significance.

[0004] Currently, techniques such as capillary electrophoresis, high-performance liquid chromatography, electrochemistry, and fluorescence sensing have been used to detect lysine. Among these, fluorescence sensors, especially LMOF-based fluorescence sensors, are the most attractive due to their high sensitivity, selectivity, and visual detection capabilities. Given their unique and excellent luminescent properties, LMOFs have proven to be highly attractive materials in the field of amino acid recognition and detection.

[0005] Patent document CN202010327126 discloses a MOF-Cd probe for detecting lysine, its preparation method, and its application, belonging to the field of amino acid detection technology. This invention uses tetrakis(4-imidazolylphenyl)ethylene as a ligand and Cd(NO3)·4H2O as a metal node to self-assemble and construct a MOF-Cd probe, achieving highly selective recognition of lysine among the eight essential amino acids. However, it cannot achieve rapid, on-site, visualized detection of lysine. Therefore, the development of a stable LMOF as a highly sensitive and efficient ideal response sensor for amino acid detection remains urgently needed. Summary of the Invention

[0006] The technical problems solved by this invention are: 1. Existing lysine detection technologies rely on expensive equipment, are cumbersome to operate, and are difficult to achieve rapid on-site detection. 2. Existing MOF-based lysine probes cannot achieve rapid on-site visualization detection.

[0007] In view of the technical problems existing in the prior art, this invention designs a cadmium-based metal-organic framework material for fluorescence detection of lysine, its preparation method, and its application. The cadmium-based metal-organic framework material of this invention has a simple preparation process and is reusable. It exhibits characteristics such as visualization, high sensitivity, and rapid response in the fluorescence activation recognition of lysine, and has strong innovation and application value.

[0008] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition definition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," etc., and similar meanings.

[0009] To solve the aforementioned technical problems, the present invention adopts the following solution:

[0010] [The first technical solution]

[0011] The molecular formula of a cadmium-based metal-organic framework (Cd-MOF) for the fluorescence detection of lysine is: [Cd(H3L)(4,4'-bipy)]·7H2O;

[0012] Wherein, L represents the trivalent anion of 4,4',4''-[1,3,5-benzenetriamide]tribenzoic acid, and 4,4'-bipy represents the 4,4'-bipyridine auxiliary ligand.

[0013] Furthermore, the cadmium-based metal-organic framework (Cd-MOF) used for the fluorescence detection of lysine belongs to the monoclinic crystal system and has a space group of P21 / n.

[0014] Furthermore, the unit cell parameters of the cadmium-based metal-organic framework (Cd-MOF) for fluorescence detection of lysine are a (Å) = 7.713(2), b (Å) = 17.532(5), c (Å) = 29.581(8), α (°) = 90, β (°) = 85.581(4), γ (°) = 90, and the unit cell volume is V (Å). 3 = 3988(2).

[0015] The uncoordinated -CONH- groups present in the structure can serve as potential recognition sites, making Cd-MOF a potential fluorescent sensing material.

[0016] [Second Technical Solution]

[0017] A method for preparing the above-mentioned cadmium-based metal-organic framework material for fluorescence detection of lysine includes the following steps:

[0018] Step 1: Dissolve the cadmium source, organic carboxylic acid ligand, and nitrogen-containing auxiliary ligand in a mixed solvent consisting of deionized water and an organic solvent to obtain a mixed solution;

[0019] Step 2: Stir the mixed solution obtained in Step 1 at room temperature and react it in a reaction vessel. Cool the reactants, wash and dry them to obtain the cadmium-based metal-organic framework material for fluorescence detection of lysine, denoted as Cd-MOF.

[0020] The organic carboxylic acid ligand is an aromatic polycarboxylic acid ligand with a phenyltriamide structure, and the nitrogen-containing auxiliary ligand is a nitrogen-containing heterocyclic ligand.

[0021] Furthermore, the cadmium source is cadmium nitrate tetrahydrate;

[0022] The organic solvent is N,N-dimethylformamide;

[0023] The organic carboxylic acid ligand is 4,4',4''-[1,3,5-benzenetriamide]tribenzoic acid;

[0024] The nitrogen-containing auxiliary ligand is 4,4'-bipyridine.

[0025] Furthermore, the mass ratio of 3,3',3''-[1,3,5-benzenetriamide]tribenzoic acid, 4,4'-bipyridine, and cadmium nitrate tetrahydrate is (3-9):2:6.

[0026] Furthermore, the deionized water and N,N-dimethylformamide are mixed at a volume ratio of 1:3.

[0027] Furthermore, in step 2, the reaction temperature in the reactor is 80-120℃, and the reaction time is 48-96h; the cooling is cooling to room temperature; and the drying conditions are drying at room temperature.

[0028] In this invention, the reaction vessel used is generally a stainless steel reaction vessel with polytetrafluoroethylene as the inner liner.

[0029] In this invention, the amount of solvent deionized water and N,N'-dimethylformamide used in step 1 is generally sufficient to achieve uniform dispersion of the solid solute, and there are no special requirements for the amount used. In some embodiments of this invention, the ratio of solid solute to solvent can be 110-170:4-12 (mg / mL).

[0030] In step 2 of the preparation method of the present invention, washing generally means washing with deionized water.

[0031] The selection of Cd(NO3)2·4H2O, H3L, and 4,4'-bipy as the basic reactants in this invention is of unique significance:

[0032] Firstly, cadmium nitrate tetrahydrate Cd(NO3)2·4H2O

[0033] This invention selects Cd(NO3)2·4H2O as the basic reactant. Firstly, because Cd... 2+ The ion is usually in a six-coordinate mode; secondly, due to Cd... 2+ Ions have d 10 Its electronic configuration makes it less prone to dd-electron transitions or fluorescence quenching effects at the metal center, which is conducive to the formation of a stable excited state.

[0034] Secondly, 3,3',3''-[1,3,5-benzenetriamide]tribenzoic acid H3L

[0035] This invention selects H3L as the basic reactant because it has the following advantages:

[0036] (1) Its chelation mode helps to improve the overall stability of the framework;

[0037] (2) The H3L ligand has three carboxylic acid (-COOH) groups and three amide (-CONH-) groups, and has a variety of flexible coordination modes;

[0038] (3) The H3L ligand has a conjugated structure, which helps to improve the luminescence performance of the material. In addition, the UV absorption peak range of the H3L ligand partially overlaps with the UV absorption range of lysine, which is expected to enable efficient detection of lysine through a competitive absorption mechanism.

[0039] Thirdly, 4,4'-bipyridine

[0040] This invention selects 4,4'-bipy as the basic reactant. Since there is a nitrogen atom at each end of its molecule, it can coordinate with two metal ions at the same time. This connection through metal-nitrogen (MN) coordination bonds is more stable and can effectively enhance the overall stability of MOF materials.

[0041] Therefore, this invention selects Cd(NO3)2·4H2O, H3L and 4,4'-bipy as basic reactants to obtain a target Cd-MOF material with high stability. Furthermore, the UV absorption peak range of the ligand H3L partially overlaps with the UV absorption range of lysine, enabling efficient detection of lysine through a competitive absorption mechanism, thus providing a favorable premise for the study of fluorescence recognition performance.

[0042] [The third technical solution]

[0043] A method for applying the above-mentioned cadmium-based metal-organic framework material for the fluorescence detection of lysine includes the following steps:

[0044] The cadmium-based metal-organic framework material for fluorescence detection of lysine was ultrasonically dispersed in deionized water to form a stable suspension, which served as the basic fluorescent probe. Then, the change in fluorescence emission intensity was tested by gradually adding lysine solution to the suspension.

[0045] Specifically, 2.0 mg of the cadmium-based metal-organic framework (Cd-MOF) prepared in this invention was ultrasonically dispersed in 3.0 mL of deionized water to form a stable suspension, which served as the basic fluorescent probe. Then, a concentration of 1.0 × 10⁻⁶ was gradually added dropwise to the Cd-MOF aqueous suspension. -2 The change in fluorescence emission intensity of M-lysine solution was tested.

[0046] With the gradual addition of lysine solution, the fluorescence intensity of Cd-MOF at the characteristic wavelength gradually increased (fluorescence enhancement occurred). Within the concentration range of 0-134 μM, the fluorescence intensity showed a good linear relationship with the lysine concentration, with a fluorescence enhancement factor of 4.3 × 10⁻⁶. 4 M -1 Linear correlation coefficient R 2 =0.996. Based on the detection limit formula LOD=3δ / s, the detection limit of lysine is calculated to be 0.27 μM.

[0047] This invention provides a method for preparing a cadmium-based metal-organic framework material for the fluorescence detection of lysine, which has the following beneficial effects:

[0048] 1. The cadmium-based metal-organic framework (Cd-MOF) fluorescent sensing material prepared by this invention is prepared by a conventional solvothermal method, which has the advantages of readily available raw materials, simple process, low cost and good reproducibility.

[0049] 2. The Cd-MOF prepared in this invention can be used as a fluorescent probe to specifically and sensitively detect lysine in the aquatic environment, with a detection limit as low as 0.27 μM. The fluorescence intensity shows a good linear relationship with the lysine concentration in the concentration range of 0-134 μM.

[0050] 3. The detection process of this invention is simple to operate, and quantitative analysis can be achieved by enhancing fluorescence intensity. Furthermore, the probe of this invention has good stability, is reusable, responds rapidly during the detection process, has high sensitivity, and exhibits obvious fluorescence enhancement. It can achieve rapid and visual detection of lysine in the aquatic environment by observing changes in fluorescence intensity, thus realizing visual detection.

[0051] 4. The Cd-MOF prepared by this invention can be further formulated into portable detection materials, facilitating rapid on-site spraying detection of liquid samples. The fluorescence color change is visible to the naked eye, expanding its practical application scenarios. The Cd-MOF prepared by this invention provides a new method and approach for preparing fluorescent sensing materials capable of efficiently detecting lysine.

[0052] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0053] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein: Attached Figure Description

[0054] Figure 1 : A schematic diagram of the Cd-MOF molecular structure synthesized in Example 1 of this invention;

[0055] Figure 2 : A schematic diagram of the Cd-MOF three-dimensional skeleton framework structure synthesized in Embodiment 1 of the present invention;

[0056] Figure 3 : The excitation and emission spectra of the Cd-MOF synthesized in Example 1 of this invention;

[0057] Figure 4 : X-ray powder diffraction pattern of Cd-MOF synthesized in Example 1 of this invention;

[0058] Figure 5 : The fluorescence response spectra of the Cd-MOF synthesized in Example 1 of this invention to different substances;

[0059] Figure 6 : This is a fluorescence spectrum change diagram of the Cd-MOF synthesized in Example 1 of the present invention after the addition of different concentrations of lysine;

[0060] Figure 7 : Linear relationship between fluorescence intensity and lysine concentration of Cd-MOF synthesized in Example 1 of this invention when the lysine concentration is in the range of 0-134 μM;

[0061] Figure 8 : This is a fluorescence response time diagram of the Cd-MOF fluorescent probe synthesized in Example 1 of this invention to lysine;

[0062] Figure 9 : This is a fluorescence comparison image of the Cd-MOF fluorescent probe solution synthesized in Example 1 of the present invention before and after the addition of lysine under 254 nm ultraviolet light irradiation;

[0063] Figure 10The image shows a fluorescence comparison of the portable detection material based on the Cd-MOF fluorescent probe synthesized in Example 1 of this invention before and after the addition of lysine, under 254 nm ultraviolet light irradiation. Detailed Implementation

[0064] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0065] Unless otherwise specified, the raw materials and chemical reagents used in the specific embodiments of the present invention are all conventional raw materials that can be obtained through commercial channels.

[0066] In an embodiment of the present invention, the method for synthesizing 3,3',3''-[1,3,5-benzenetriamide]tribenzoic acid is as follows:

[0067] Weigh 4.8 g of trimesic acid and add 10 mL of SOCl2 solution under nitrogen protection, followed by 2 drops of N,N-dimethylformamide. After reflux for 10 h, a pale yellow solution is obtained. After cooling to room temperature, 1,3,5-benzenetricarboxyl chloride is obtained. Subsequently, 6 g of 3-aminobenzoic acid and 3 mL of triethylamine are dissolved in 80 mL of N,N-diethylformamide solution. The obtained 1,3,5-benzenetricarboxyl chloride solid is then added directly to the above solution, stirred at room temperature for 16 h, and then 500 mL of water is added. The resulting white precipitate is filtered and then dried under vacuum.

[0068] Example 1

[0069] Step 1: Add 60 mg of cadmium nitrate tetrahydrate, 60 mg of 3,3',3''-[1,3,5-benzenetriamide]tribenzoic acid, 20 mg of 4,4'-bipy, 2 mL of deionized water and 6 mL of N,N'-dimethylformamide to a 25 mL hydrothermal synthesis vessel and stir magnetically until a uniform milky white suspension is formed.

[0070] Step 2: The milky white suspension obtained in Step 1 was packaged and placed into a reaction vessel. The reaction vessel was then placed in an oven and heated to 100°C, and the mixed solution was allowed to react in the reaction vessel for 72 hours. The reaction vessel was then removed from the oven and allowed to cool to room temperature for 10 hours. The mixed solution after the reaction was then removed from the reaction vessel and filtered and dried for 10 hours to obtain cadmium-based metal-organic framework Cd-MOF with a yield of 80.8%.

[0071] The crystallographic data of the cadmium-based metal-organic framework Cd-MOF, as determined by testing, are as follows: it belongs to the monoclinic crystal system with space group P21 / n.

[0072] Cell parameters: a (Å) = 7.713(2), b (Å) = 17.532(5), c (Å) = 29.581(8), α (°) = 90, β (°) = 85.581(4), γ (°) = 90, V (Å) 3 = 3988(2).

[0073] The molecular structure and three-dimensional framework structure of the cadmium-based metal-organic framework fluorescent probe in this embodiment are as follows: Figure 1 and 2 As shown.

[0074] In Example 1, the Cd-MOF material synthesized was ultrasonically dispersed in deionized water to prepare a stable suspension. Its excitation and emission spectra were measured using a fluorescence spectrometer, and the results are as follows: Figure 3 As shown.

[0075] Figure 3 The results show that the maximum excitation wavelength of the Cd-MOF synthesized in this embodiment is 320 nm, and the maximum emission wavelength is 430 nm, which is attributed to charge transfer within the ligand. The excellent fluorescence properties of Cd-MOF lay the foundation for the fluorescence detection of lysine.

[0076] Example 2

[0077] Step 1: Add cadmium nitrate tetrahydrate (30 mg), 3,3',3''-[1,3,5-benzenetriamide]tribenzoic acid (60 mg), 4,4'-bipy (20 mg), 1 mL of deionized water and 3 mL of N,N'-dimethylformamide to a 25 mL hydrothermal synthesis reactor, stir well to obtain a mixed solution;

[0078] Step 2: The mixed solution obtained in Step 1 is packaged and placed into a reaction vessel. The reaction vessel is then placed in an oven and heated to 80°C, and the mixed solution is reacted in the reaction vessel for 96 hours. The reaction vessel is then removed from the oven and the temperature is allowed to drop to room temperature for 12 hours. The reacted mixed solution is then removed from the reaction vessel and filtered and dried for 12 hours to obtain a cadmium-based metal-organic framework (Cd-MOF) for the fluorescence detection of lysine, with a yield of 68.7%.

[0079] The structure of the Cd-MOF synthesized in this embodiment is the same as that in Example 1.

[0080] Example 3

[0081] Step 1: Add cadmium nitrate tetrahydrate (90 mg), 3,3',3''-[1,3,5-benzenetriamide]tribenzoic acid (60 mg), 4,4'-bipy (20 mg), 3 mL of deionized water and 9 mL of N,N'-dimethylformamide to a 25 mL hydrothermal synthesis reactor, stir well to obtain a mixed solution;

[0082] Step 2: The mixed solution obtained in Step 1 was packaged and placed into a reaction vessel. The reaction vessel was then placed in an oven and heated to 120°C, and the mixed solution was allowed to react in the reaction vessel for 48 hours. The reaction vessel was then removed from the oven and allowed to cool to room temperature for 8 hours. The reacted mixed solution was then removed from the reaction vessel and filtered and dried for 8 hours to obtain a cadmium-based metal-organic framework (Cd-MOF) for the fluorescence detection of lysine, with a yield of 66.3%.

[0083] The structure of the Cd-MOF synthesized in this embodiment is the same as that in Example 1.

[0084] The crystal structure and fluorescence sensing performance of the Cd-MOF obtained in Example 1 were tested, and the results were verified according to the attached specification. Figures 1-10 Further explanation:

[0085] Firstly, Cd-MOF fluorescent probe powder diffraction (PXRD) test:

[0086] The phase purity of the Cd-MOF fluorescent detection probe prepared in Example 1 was determined using an X-ray powder diffractometer (Bruker AXS D8 Advance), with Cu-Kα radiation, λ = 1.5418 Å, a scanning range of 5–50°, and a scanning speed of 6°·min. –1 Spectrum as follows Figure 4 As shown.

[0087] from Figure 4 As can be seen, the PXRD pattern of the Cd-MOF fluorescent detection probe obtained by the test is consistent with the pattern of the single crystal structure fitting, indicating that the Cd-MOF fluorescent detection probe has good purity.

[0088] Secondly, a selective study of lysine detection using Cd-MOF fluorescence:

[0089] 2.0 mg of Cd-MOF powder was dispersed in 3.0 mL of solution with a concentration of 1.0 × 10⁻⁶. –3 mol·L –1Suspensions were prepared by sonicating an aqueous solution containing lysine (Lys), urine (potassium chloride (KCl), sodium chloride (NaCl), ammonium chloride (NH4Cl), sodium sulfate (Na2SO4), urea (Urea), glucose (Glucose), creatinine (Creatinine), creatine (Creatine)) and plasma (KCl, NaCl, magnesium chloride (MgCl2), calcium chloride (CaCl2), sodium bicarbonate (NaHCO3), Urea, glucose, L-proline (L-Proline)) for 15 min. The fluorescence spectra of the suspensions were then tested under the same fluorescence testing conditions. Figure 5 The following graph shows the results of the selectivity test for different substances of the Cd-MOF synthesized in Example 1:

[0090] from Figure 5 It can be seen that the fluorescence intensity of the Cd-MOF material at 430 nm is significantly enhanced only when lysine is added, while the influence of other substances on the fluorescence signal is negligible, indicating that the probe has high selectivity for lysine.

[0091] Thirdly, a study on the sensitivity of Cd-MOF fluorescence detection of lysine:

[0092] To quantitatively detect lysine, a concentration of 1×10⁻⁶ was added dropwise to the Cd-MOF suspension. –2 M·L –1 A fluorescent titration experiment was performed on an aqueous solution of lysine. Figure 6 The fluorescence spectrum of the Cd-MOF synthesized in Example 1 after the addition of different concentrations of lysine is shown in the figure. Figure 7 For lysine concentrations in the range of 0-134 μM, the linear relationship between the fluorescence intensity of the Cd-MOF synthesized in Example 1 of this invention at an excitation wavelength of 320 nm and the lysine concentration is shown.

[0093] from Figure 6 It can be seen that the luminescence intensity of Cd-MOF gradually increases with increasing lysine concentration. Furthermore, within the concentration range of 0-134 μM, there is a good linear relationship between fluorescence intensity and lysine concentration, with a linear correlation coefficient R0. 2 =0.996. Therefore, the lysine content can be quantitatively determined using the standard curve method within the concentration range of 0-134 μM.

[0094] Based on the slope (S) of the linear equation and the standard deviation (σ) of 10 repeated fluorescence measurements of the blank solution, the detection limit of the Cd-MOF fluorescent probe for lysine was calculated to be 0.27 μM according to the detection limit formula LOD=3δ / s.

[0095] Therefore, Cd-MOF can achieve highly sensitive fluorescence recognition of lysine ( Figure 7 ).

[0096] Fourth, a study on the time response of lysine detection using Cd-MOF fluorescence:

[0097] To evaluate the response kinetics, the change in fluorescence intensity over time after the addition of lysine was investigated. Figure 8 This is a fluorescence response time diagram of the Cd-MOF fluorescent probe synthesized in Example 1 to lysine. Figure 8 As shown, the fluorescence intensity rapidly increased within 8 s and reached a plateau within 120 s, indicating that the Cd-MOF probe has a rapid response.

[0098] Fifth, a study on the performance of Cd-MOF in visual fluorescence detection of lysine:

[0099] Figure 9 This image shows a fluorescence comparison of the Cd-MOF fluorescent probe solution synthesized in Example 1 of this invention before and after the addition of lysine, under 254 nm UV light irradiation. Figure 9 It can be observed that when lysine is added to the Cd-MOF probe solution under 254 nm ultraviolet light, the solution changes from colorless and transparent to bright blue fluorescence, and this change is clearly visible to the naked eye, thus realizing the visual detection of lysine.

[0100] To achieve portable and rapid detection of lysine in the environment, this invention also provides a portable test strip based on a Cd-MOF probe and its preparation method. The preparation process of the convenient detection material is as follows: Tussah silk fabric is degummed using a sodium carbonate aqueous solution. Then, the pretreated tussah silk fabric is cut into pieces with a size of 4 × 0.5 cm. 2 Long strips were thoroughly immersed in an aqueous suspension of Cd-MOF for 10 minutes. They were then removed and dried in a 60°C oven for 4 hours to obtain the Cd-MOF@tussah silk sample.

[0101] Applications of Cd-MOF@tussah silk detection, such as Figure 10 As shown: When the test solution (such as 100 μM lysine solution) is sprayed onto the portable detection material Cd-MOF@tussah silk, it can be seen that under 254 nm ultraviolet light irradiation, the strong blue fluorescence of Cd-MOF@tussah silk immediately turns into a visible black color.

[0102] This invention provides a fluorescent sensing material based on a cadmium-based metal-organic framework and its applications. This probe exhibits high selectivity for lysine, enabling highly sensitive and rapid quantitative detection of lysine in aqueous systems and simulated human urine systems, with a detection limit as low as 0.27 μM and a response time as low as 120 s. This invention prepares the fluorescent probe into a portable tussah silk fabric composite material (Cd-MOF@tussah silk). This composite material is characterized by its ease of operation and visualized results, and shows promising application potential for the detection of lysine in actual human urine.

[0103] The present invention has been described above by way of example with reference to the embodiments and accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A cadmium-based metal-organic framework material for the fluorescence detection of lysine, characterized in that: The molecular formula of the cadmium-based metal-organic framework material used for the fluorescence detection of lysine is [Cd(H3L)(4,4'-bipy)]·7H2O; Wherein, L represents the trivalent anion of 4,4',4''-[1,3,5-benzenetriamide]tribenzoic acid, and 4,4'-bipy represents the 4,4'-bipyridine auxiliary ligand.

2. The cadmium-based metal-organic framework material for fluorescence detection of lysine according to claim 1, characterized in that: The cadmium-based metal-organic framework material used for the fluorescence detection of lysine belongs to the monoclinic crystal system and has a space group of P21 / n.

3. The cadmium-based metal-organic framework material for fluorescence detection of lysine according to claim 1, characterized in that: The unit cell parameters of the cadmium-based metal-organic framework material used for the fluorescence detection of lysine are a (Å) = 7.713(2), b (Å) = 17.532(5), c (Å) = 29.581(8), α (°) = 90, β (°) = 85.581(4), γ (°) = 90, and the unit cell volume is V (Å). 3 ) = 3988(2).

4. A method for preparing a cadmium-based metal-organic framework material for fluorescent detection of lysine according to any one of claims 1-3, characterized in that, Including the following methods: Step 1: Dissolve the cadmium source, organic carboxylic acid ligand, and nitrogen-containing auxiliary ligand in a mixed solvent consisting of deionized water and an organic solvent to obtain a mixed solution; Step 2: Stir the mixed solution obtained in Step 1 at room temperature and react it in a reaction vessel. Cool the reactants, wash and dry them to obtain the cadmium-based metal-organic framework material for fluorescence detection of lysine, denoted as Cd-MOF. The organic carboxylic acid ligand is an aromatic polycarboxylic acid ligand with a phenyltriamide structure, and the nitrogen-containing auxiliary ligand is a nitrogen-containing heterocyclic ligand.

5. The method for preparing a cadmium-based metal-organic framework material for fluorescence detection of lysine according to claim 4, characterized in that: The cadmium source is cadmium nitrate tetrahydrate; The organic solvent is N,N-dimethylformamide; The organic carboxylic acid ligand is 4,4',4''-[1,3,5-benzenetriamide]tribenzoic acid; The nitrogen-containing auxiliary ligand is 4,4'-bipyridine.

6. The method for preparing cadmium-based metal-organic framework materials for fluorescence detection of lysine according to claim 5, characterized in that: The mass ratio of 3,3',3''-[1,3,5-benzenetriamide]tribenzoic acid, 4,4'-bipyridine, and cadmium nitrate tetrahydrate is (3-9):2:

6.

7. The method for preparing a cadmium-based metal-organic framework material for fluorescence detection of lysine according to claim 5, characterized in that: The deionized water and N,N-dimethylformamide are mixed at a volume ratio of 1:

3.

8. The method for preparing a cadmium-based metal-organic framework material for fluorescence detection of lysine according to claim 5, characterized in that: In step 2, the reaction temperature in the reactor is 80-120℃, and the reaction time is 48-96 h; the cooling is to cool to room temperature; and the drying conditions are to dry at room temperature.

9. A method for applying the cadmium-based metal-organic framework material for fluorescence detection of lysine as described in any one of claims 1-3, characterized in that, Includes the following steps: The cadmium-based metal-organic framework material for the fluorescence detection of lysine was ultrasonically dispersed in deionized water to form a stable suspension, which served as the basic fluorescent probe. The change in fluorescence emission intensity was then tested by gradually adding lysine solution to the suspension.

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