Zinc-based metal organic framework material as well as preparation method and application thereof

Abstract

The invention relates to a zinc-based metal organic framework material as well as a preparation method and application thereof, 1, 4-bis (2-ethylimidazole-1-yl) terephthalic acid is taken as an organic ligand, transition metal zinc is taken as a forming body, and the zinc-based metal organic framework material is synthesized through a solvothermal method. The zinc-based metal organic framework material is combined with calcium ions to serve as a fluorescent probe to be used as a ratio fluorescent probe of doxycycline hydrochloride in a water system, and rapid detection of the content of doxycycline hydrochloride can be achieved. The method for determining the doxycycline hydrochloride in the water has the characteristics of quick response, high selectivity, high sensitivity, high accuracy and the like, and compared with the existing doxycycline hydrochloride detection technology, the method shows good market application potential due to low cost, high efficiency, high sensitivity, high selectivity and simple operation.

Description

Technical Field

[0001] The invention relates to the field of doxycycline hydrochloride detection, and in particular to a zinc-based metal organic framework material and a preparation method and application thereof. Background Art

[0002] Doxycycline hydrochloride, as a kind of tetracycline antibiotic, has been widely used in aquaculture due to its excellent antibacterial properties. The drug can effectively treat Gram-negative bacteria and chlamydia or mycoplasma infections and increase the output of aquatic products. However, its abuse has brought serious environmental problems. Excessive use of doxycycline hydrochloride can inhibit biological growth, affect steroid production, lead to endocrine disorders in aquatic organisms, and then destroy the entire ecosystem. In addition, the accumulation of the drug in aquatic animals may also enter the human body through the food chain, causing damage to the human digestive system, central nervous system and blood system, and seriously threatening human life and health. At present, the methods used to detect doxycycline hydrochloride mainly include high performance liquid chromatography (HPLC), high performance liquid chromatography-mass spectrometry (HPLC-MS), ultra-high performance liquid chromatography-mass spectrometry, thin layer chromatography, electrochemical voltammetry, enzyme-linked immunosorbent assay, etc. However, these methods usually have defects such as high cost, poor selectivity, low sensitivity, and complex operation. Therefore, it is urgent to find a method that can quickly and effectively detect doxycycline hydrochloride.

[0003] Metal-Organic Frameworks (MOFs) are a new type of porous material that shows great potential in luminescent sensing due to its unique three-dimensional framework structure and adjustable pore size. By rationally optimizing the pore size and morphology of the metal-organic framework material, rapid and sensitive detection of the target analyte can be achieved. When metal ions are absorbed by the pores of the metal-organic framework material as analytical reagents, they will contact the metal ions or ligands in the organic framework, resulting in electron or energy transfer, leading to enhanced or weakened fluorescence properties, thereby achieving the identification and detection of the target analyte. In recent years, due to the rapid development of fluorescence sensing technology of luminescent metal-organic framework materials with the advantages of short response time, low cost, high sensitivity and high efficiency, researchers in various fields have also successively established a variety of metal-organic framework material fluorescence sensors with different functions. Zinc ions are d 10 Transition metal ions with electronic configurations can promote radiation emission and are suitable for constructing luminescent metal-organic framework materials. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a zinc-based metal organic framework material which can quickly detect the content of doxycycline hydrochloride in water and has rapid response, high selectivity and high sensitivity, as well as a preparation method and application thereof.

[0005] In order to solve the above problems, the technical solution of the present invention is:

[0006] A zinc-based metal organic framework material, the molecular formula of which is as follows:

[0007] Zn[C 18 H 16 O4N4]·C2H6SO·2H2O.

[0008] A method for preparing a zinc-based metal organic framework material, the specific steps of which are as follows:

[0009] S1: Preparation of organic ligand-metal salt solution

[0010] Weighing an organic ligand {1,4-bis(2-ethylimidazol-1-yl)-2,5-terephthalic acid} and a metal salt (Zn(NO3)2·6H2O) in a mass ratio of 1:3, adding them into a mixed solvent of DMF, DMSO and ethanol, wherein the mass volume ratio of the organic ligand to DMSO is 4 g / L, and stirring evenly to obtain a prepared organic ligand-metal salt solution;

[0011] S2: Solvothermal preparation of zinc-based metal organic frameworks

[0012] The organic ligand-metal salt solution was poured into a glass bottle, and heated in an oven at 80°C for 3 days to obtain white transparent rhombus-shaped crystals, which were then washed, filtered, dried, and ground to obtain zinc-based metal organic framework material powder (denoted as Zn-MOF).

[0013] Furthermore, the volume ratio of DMF, DMSO and ethanol is 1:1:1.

[0014] Application of a zinc-based metal organic framework material in the rapid detection of doxycycline hydrochloride in water.

[0015] Application of a zinc-based metal organic framework material in rapid detection of doxycycline hydrochloride in water, wherein the zinc-based metal organic framework material is combined with Ca 2+ Mixed preparation of ratiometric fluorescent probe for rapid detection of doxycycline hydrochloride in water.

[0016] An application of a zinc-based metal organic framework material in the rapid detection of doxycycline hydrochloride in water, wherein the ratio fluorescence probe for rapid detection of doxycycline hydrochloride in water has the following specific steps:

[0017] The zinc-based metal organic framework material powder was added into deionized water, and after being evenly dispersed by ultrasonic, a zinc-based metal organic framework material dispersion liquid with a mass volume ratio of 1 g / L was prepared; the zinc-based metal organic framework material dispersion liquid was mixed with 0.02 mol·L -1 The calcium chloride solution was mixed in a volume ratio of 1:1 to obtain a ratio fluorescent probe of doxycycline hydrochloride.

[0018] The beneficial effects of the present invention are:

[0019] (1) Zn-MOF and Ca 2+ When doxycycline hydrochloride is present in the liquid, doxycycline hydrochloride can react with the Ca in the fluorescent probe through the intramolecular oxygen of ketone and hydroxyl groups. 2+ Combined to form a stable six-membered ring chelate. At this time, the conformational rotation of the doxycycline hydrochloride molecule is restricted, the rigid plane increases, and the radiation energy increases, resulting in the doxycycline hydrochloride and Ca 2+ The complex will form a new obvious fluorescence peak at 550nm, resulting in a decrease in fluorescence at 430nm and an increase in fluorescence at 550nm, thereby realizing the ratio fluorescence detection of doxycycline hydrochloride.

[0020] (2) Simple operation and low cost. It can quickly detect the content of doxycycline hydrochloride in water, has the characteristics of rapid response, high selectivity and high sensitivity, and can realize visual rapid detection of doxycycline hydrochloride through changes in fluorescence intensity. Compared with the existing doxycycline hydrochloride detection technology, the doxycycline hydrochloride detection reagent is low in cost, effective, simple to operate and easy to implement, and has a good market application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a ligand structure diagram used in the zinc-based metal organic framework material powder (Zn-MOF) prepared by the present invention;

[0022] Figure 2 It is a Zn(II) coordination environment diagram of the zinc-based metal organic framework material powder (Zn-MOF) prepared by the present invention;

[0023] Figure 3 It is a three-dimensional structure diagram of the zinc-based metal organic framework material powder (Zn-MOF) prepared by the present invention;

[0024] Figure 4 It is a topological structure diagram of the zinc-based metal organic framework material powder (Zn-MOF) prepared by the present invention;

[0025] Figure 5 It is the XRD diffraction spectrum of the zinc-based metal organic framework material powder (Zn-MOF) prepared by the present invention;

[0026] Figure 6 It is a ratiometric fluorescence probe fluorescence intensity change diagram of the zinc-based metal organic framework material powder (Zn-MOF) prepared by the present invention under different doxycycline hydrochloride concentrations;

[0027] Figure 7is a linear relationship diagram of the ratiometric fluorescent probe of the present invention under different concentrations of doxycycline hydrochloride;

[0028] Figure 8 This is an anti-interference experimental diagram of the ratiometric fluorescent probe of the present invention;

[0029] Fig. 9 This is a diagram showing the effect of the zinc-based metal organic framework material powder (Zn-MOF) prepared by the present invention on detecting tetracycline antibiotics alone. DETAILED DESCRIPTION

[0030] Example 1

[0031] S1: Solvothermal preparation of zinc-based metal organic frameworks

[0032] Weigh the organic ligand 1,4-bis(2-ethylimidazol-1-yl)-2,5-terephthalic acid ( )40 mg and metal salt Zn(NO3)2·6H2O120 mg are completely dissolved in 30 mL of a mixed solvent of DMF, DMSO and ethanol in a volume ratio of 1:1:1, and stirred evenly to obtain a mixed solution; the mixed solution is poured into a thick-walled pressure-resistant glass bottle, and then placed in an oven and heated continuously at 80°C for 3 days to obtain white transparent rhombus-shaped crystals, which are washed, filtered, dried and ground to obtain zinc-based metal organic framework material (Zn-MOF) powder;

[0033] S2: Preparation of ratiometric fluorescent probe for doxycycline acid

[0034] (1) Weighing 10 mg of zinc-based metal organic framework material powder, placing it in 10 mL of deionized water, and uniformly dispersing it by ultrasonication to obtain a zinc-based metal organic framework material dispersion;

[0035] (2) Weigh 22 mg of anhydrous calcium chloride and add 10 mL of distilled water to make a 0.02 mol·L -1 of calcium chloride solution;

[0036] (3) 0.9 mL of the zinc-based metal organic framework material dispersion prepared in step (1) and 0.9 mL of the calcium chloride solution prepared in step (2) were mixed to obtain a ratiometric fluorescent probe of doxycycline hydrochloride.

[0037] 1. Structure and characterization of zinc-based metal-organic frameworks

[0038] (1) Structural analysis

[0039] In order to analyze the structure of Zn-MOF, a Bruker D8VENTURE X-ray single crystal diffractometer was used for testing at room temperature. Monochromatic microfocused Cu Kα radiation was used, and the incident angle λ was 0.71073 The diffraction data can be obtained by using the multi-scanning absorption correction mode. In order to analyze the single crystal diffraction data to obtain the structure of the crystal, the software Olex2 was used for analysis, and the unit cell parameter data obtained are as follows.

[0040]

[0041]

[0042] Figure 1 is the structure of the ligand used in the prepared Zn-MOF; Figure 2 is the coordination environment of Zn(II) in the prepared Zn-MOF. 2+ Coordinated with 2 nitrogen atoms and 2 oxygen atoms, of which two nitrogen atoms come from the imidazole functional groups in the ligand and two oxygen atoms come from the carboxyl functional groups in the ligand; Figure 3 The three-dimensional structure diagram of Zn-MOF; Figure 4 .Topological structure diagram of Zn-MOF.

[0043] (2) Powder diffraction characterization

[0044] Figure 5 is the powder line diffraction spectrum of the prepared Zn-MOF, such as Figure 5 As shown, the diffraction peaks in the simulated PXRD and the actual measured PXRD correspond well, indicating that Zn-MOF is successfully synthesized and the complexes are all pure phases.

[0045] 2. Calculation of detection limit

[0046] Take 1.8 mL of the ratio fluorescence probe of doxycycline hydrochloride prepared in Example 1, mix it evenly with 0.2 mL of the sample to be tested, then excite the mixed solution to be tested under a 313 nm ultraviolet lamp, and detect the content of doxycycline hydrochloride in the water body according to the change in the fluorescence intensity of the sample. With the concentration of doxycycline hydrochloride as the horizontal axis and the fluorescence intensity as the vertical axis, a linear relationship model is constructed and the detection limit is calculated.

[0047] The specific steps are as follows:

[0048] (1) Prepare a series of doxycycline hydrochloride standard solutions with known concentrations (the concentrations are: 0, 0.2 mM, 0.4 mM, 0.6 mM, 0.8 mM, 1 mM, 1.2 mM, 1.4 mM, 1.6 mM, 1.8 mM, 2 mM, 2.2 mM, 2.4 mM, 2.6 mM, 2.8 mM, 3 mM);

[0049] (2) Take 1.8 mL of the ratiometric fluorescent probe of doxycycline hydrochloride prepared in Example 1, add 0.2 mL of the above-mentioned standard solution of doxycycline hydrochloride of known concentration, mix well, and measure its fluorescence intensity at an excitation wavelength of 313 nm.

[0050] Figure 6 The graph shows the change in fluorescence intensity when 0.2 mL of doxycycline hydrochloride standard solution of different concentrations is added to the doxycycline hydrochloride fluorescent probe. Figure 6 It can be clearly seen that as the concentration of doxycycline hydrochloride increases, the fluorescence intensity of the doxycycline hydrochloride fluorescent probe gradually quenches at 430 nm and gradually increases at 550 nm. Figure 7 As shown in the figure, in the range of 0-160 μM, there is a linear relationship between the ratio of the fluorescence intensity of the doxycycline hydrochloride fluorescent probe and the concentration of doxycycline hydrochloride. The linear equation is F 550 / F 430 =0.00799C-0.03472, R 2 =0.98135, where C represents the concentration of doxycycline hydrochloride in micromoles / liter. The limit of detection (LOD) formula is: LOD = 3σ / K sv , the detection limit of this doxycycline hydrochloride fluorescent probe was calculated to be 1.43 μM. In the range of 180-300 μM, the linear equation between the ratio of the fluorescence intensity of the doxycycline hydrochloride fluorescent probe and the concentration of doxycycline hydrochloride is F 550 / F 430 =0.02821C-3.73046, R 2 =0.97388 (where σ is the standard deviation of the fluorescence intensity of 11 blank experiments to test the doxycycline hydrochloride fluorescent probe without adding any ions, and in this experiment σ = 0.003337. K sv represents the quenching constant (μM -1 )).

[0051] 3. Interference Experiment

[0052] Considering that the real water conditions are complex and diverse, in order to evaluate the selectivity of the ratiometric fluorescent probe for rapid detection of doxycycline hydrochloride in water, several common antibiotics were selected for anti-interference experiments, such as Figure 8As shown. Prepare 10mM of the same concentration of doxycycline hydrochloride, oxytetracycline, chloramphenicol, roxithromycin, tetracycline, thiamphenicol, azithromycin, and chlortetracycline hydrochloride. Take the doxycycline hydrochloride ratio fluorescence probe as the blank sample. After adding 50μL of doxycycline hydrochloride, its ratio fluorescence probe intensity is significantly enhanced, indicating that the doxycycline hydrochloride ratio fluorescence probe is highly sensitive to doxycycline hydrochloride. However, after adding 50μL of the other antibiotics mentioned above, there is no obvious change in the ratio fluorescence probe intensity of doxycycline hydrochloride in water for rapid detection; only when similar tetracycline antibiotics are added, the ratio fluorescence intensity will increase slightly. However, compared with the ratio fluorescence intensity of the added doxycycline hydrochloride, the ratio fluorescence intensity of tetracycline antibiotics is relatively weak, so the effect of tetracycline antibiotics on the doxycycline hydrochloride ratio fluorescence probe can be ignored, indicating that the doxycycline hydrochloride ratio fluorescence probe is selective.

[0053] 4. Comparison of the effects of the Zn-MOF organic framework material of the present invention and the doxycycline hydrochloride ratio fluorescence probe of the present invention in detecting doxycycline hydrochloride

[0054] In order to explore the superiority of the doxycycline hydrochloride ratio fluorescent probe, the zinc-based metal organic framework material powder of the present invention was tested for the effect of tetracycline antibiotics alone.

[0055] The same concentration of 10mM oxytetracycline, tetracycline, chloramphenicol hydrochloride and doxycycline hydrochloride were prepared, and 50μL of each was added to investigate their effects on the Zn-MOF organic framework material and the doxycycline hydrochloride ratio fluorescence probe.

[0056] Among them, after adding chlortetracycline hydrochloride, the quenching rate of Zn-MOF organic framework material reached 28.23%, and after adding doxycycline hydrochloride, the quenching rate of Zn-MOF organic framework material reached 76.93%, and the response effect of doxycycline hydrochloride was 2.72 times that of chlortetracycline hydrochloride; when using doxycycline hydrochloride ratio fluorescence probe, adding chlortetracycline hydrochloride, the fluorescence intensity of doxycycline hydrochloride ratio fluorescence probe was 2.15, and adding doxycycline hydrochloride, the fluorescence intensity of doxycycline hydrochloride ratio fluorescence probe was 36.93, and its corresponding effect was 17.2 times that of chlortetracycline hydrochloride. Therefore, compared with the detection of zinc-based metal organic framework material powder alone, the method of using doxycycline hydrochloride ratio fluorescence probe can greatly increase the detection effect of doxycycline hydrochloride and improve its accuracy.

[0057] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A zinc-based metal organic framework material, characterized in that: The molecular formula of this material is as follows: Zn[C 18 H 16 O4N4]·C2H6SO·2H2O。 2. A method for preparing the zinc-based metal organic framework material as claimed in claim 1, wherein the specific steps are as follows: S1: Preparation of organic ligand-metal salt solution Weighing an organic ligand 1,4-bis(2-ethylimidazol-1-yl)-2,5-terephthalic acid and a metal salt (Zn(NO3)2·6H2O) in a mass ratio of 1:3, adding them to a mixed solvent of DMF, DMSO and ethanol, wherein the mass volume ratio of the organic ligand to DMSO is 4 g / L, and stirring evenly to obtain a prepared organic ligand-metal salt solution; S2: Solvothermal preparation of zinc-based metal organic frameworks The organic ligand-metal salt solution is poured into a glass bottle, and heated in an oven at 80° C. for 3 days to obtain white transparent rhombus-shaped crystals, which are then washed, filtered, dried, and ground to obtain zinc-based metal organic framework material powder.

3. The zinc-based metal organic framework material according to claim 1, characterized in that: The volume ratio of DMF, DMSO and ethanol is 1:1:

1.

4. Use of the zinc-based metal organic framework material as claimed in claim 1 in the rapid detection of doxycycline hydrochloride in water.

5. The use of the zinc-based metal organic framework material according to claim 4 in the rapid detection of doxycycline hydrochloride in water, wherein the zinc-based metal organic framework material is combined with Ca 2+ Mixed preparation of ratiometric fluorescent probe for rapid detection of doxycycline hydrochloride in water.

6. The use of the zinc-based metal organic framework material according to claim 4 in the rapid detection of doxycycline hydrochloride in water, wherein the ratio fluorescence probe for rapid detection of doxycycline hydrochloride in water comprises the following specific steps: The zinc-based metal organic framework material powder was added into deionized water, and after being evenly dispersed by ultrasonic, a zinc-based metal organic framework material dispersion liquid with a mass volume ratio of 1 g / L was prepared; the zinc-based metal organic framework material dispersion liquid was mixed with 0.02 mol·L -1 The calcium chloride solution was mixed in a volume ratio of 1:1 to obtain a ratio fluorescent probe of doxycycline hydrochloride.

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