Luminescent probe based on europium-based metal-organic framework and preparation method and application thereof
By using a europium-based metal-organic framework-based luminescent probe, the high cost and complexity of existing technologies for detecting cevin and enrofloxacin have been solved, enabling rapid, simple, and low-cost specific detection that is suitable for food safety testing.
Patent Information
- Application Number
- CN202610430037.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-02
- Publication Date
- 2026-05-01
AI Technical Summary
In existing technologies, the detection of drug residues in cevin and enrofloxacin relies on large-scale instruments and equipment, which are costly and involve complex sample pretreatment, making it difficult to meet the needs of rapid on-site screening and large-scale immediate sample testing.
A luminescent probe based on europium-based metal-organic framework was developed as a bifunctional fluorescence sensing platform. It enables the specific identification and quantitative detection of cevin and enrofloxacin in aqueous solution, and features high sensitivity, strong anti-interference ability, recyclability, and simple and quick operation.
It enables rapid, simple, and low-cost specific detection of cevin and enrofloxacin, with good anti-interference ability and stability, and is suitable for rapid on-site screening and large-scale sample testing.
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Abstract
Description
Luminescent probes based on europium-based metal-organic frameworks, their preparation methods and applications Technical Field
[0001] This invention relates to the fields of fluorescent sensing materials and food safety detection technology, and in particular to luminescent probes based on europium-based metal-organic frameworks, their preparation methods and applications. Background Technology
[0002] In today's complex economic and consumer environment, food safety remains a paramount concern. In modern agriculture, animal husbandry, and aquaculture, pesticides (such as carbaryl) help control pests and diseases and increase yields; broad-spectrum antibiotics (such as enrofloxacin) are used to treat various bacterial diseases due to their high antibacterial activity. However, improper and excessive use can lead to excessive drug residues that enter the human body and potentially cause lasting health hazards. Therefore, establishing a simple, reliable, sensitive, selective, recyclable, and rapid-response method for detecting drug residues is of great significance.
[0003] Currently, the detection of carbaryl and enrofloxacin residues mainly relies on precise analytical techniques using large-scale instruments. For carbaryl detection, common methods include high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). HPLC, because it does not require high-temperature vaporization and can effectively separate the thermally unstable carbaryl without causing its decomposition, is widely used for quantitative analysis in food and environmental samples. For enrofloxacin detection, HPLC is also the mainstream quantitative method due to its high sensitivity, high selectivity, and good repeatability. For precise determination of trace residues, liquid chromatography-tandem mass spectrometry (LC-MS / MS) is the preferred method due to its excellent separation capabilities and high specificity. my country's national standard GB23200.113 also standardizes the relevant detection methods.
[0004] While liquid chromatography and its coupled techniques are important methods for detecting drug residues, the detection process is usually carried out on large-scale instruments, which is costly. Furthermore, the sample pretreatment process is complex, time-consuming, and requires specialized technicians, resulting in a long analysis cycle for a single sample, making it difficult to meet the needs of rapid on-site screening and large-scale real-time sample testing.
[0005] Therefore, developing a novel detection technology that is simple to operate, has a fast response, is low in cost, highly sensitive, and environmentally friendly for the efficient monitoring of drug residues such as carbaryl and enrofloxacin has become an important research direction in the field of food safety analysis. Summary of the Invention
[0006] To address the shortcomings of the prior art, the present invention aims to provide a luminescent probe based on europium-based metal-organic frameworks, its preparation method, and its application. The synthesized europium-based metal-organic framework material can be used as a bifunctional fluorescent probe to achieve specific identification and quantitative detection of cevin and enrofloxacin in aqueous solution. It has significant advantages such as high sensitivity, strong anti-interference ability, recyclability, and simple and quick operation.
[0007] The technical solution adopted by this invention to solve its technical problem is as follows: a luminescent probe based on a europium-based metal-organic framework is provided, wherein the luminescent probe is a europium-based metal-organic framework material with the chemical formula Eu(phen)(5-hipa)NO3. - In this context, phen is a 1,10-phenanthroline ligand, 5-hipa is a 5-hydroxyisophthalic acid ligand, and the luminescent probe has a dinuclear Eu cluster as its metal center.
[0008] Furthermore, in the europium-based metal-organic framework material, the Eu ion has a nine-coordinate structure, connecting four oxygen atoms from 5-hydroxyisophthalic acid, two nitrogen atoms from 1,10-phenanthroline, and one nitrogen atom from NO3. - It has one nitrogen atom and two oxygen atoms.
[0009] Furthermore, the europium-based metal-organic framework material has a two-dimensional layered structure, belongs to the monoclinic crystal system, and has a space group of C2 / c.
[0010] A method for preparing a luminescent probe based on a europium-based metal-organic framework includes the following steps: (1) dissolving 1,10-phenanthroline, 5-hydroxyisophthalic acid and europium nitrate hexahydrate in a mixed solvent to obtain a suspension; (2) subjecting the suspension to ultrasonic treatment, and then placing it in a reaction vessel for a solvothermal reaction; (3) after the reaction is completed, allowing it to cool naturally, filtering or picking out the crystals, washing and drying to obtain a europium-based metal-organic framework material.
[0011] Further, in step (1), the molar ratio of 1,10-phenanthroline, 5-hydroxyisophthalic acid and europium nitrate hexahydrate is 0.01 : 0.01 : 0.02; the mixed solvent is a mixture of N,N-dimethylformamide and deionized water, and the volume ratio of N,N-dimethylformamide and deionized water is 1:1.
[0012] Furthermore, in step (2), the temperature of the solvothermal reaction is 100°C and the time is 3 days.
[0013] Furthermore, in step (3), the drying conditions are drying at 60 °C for 6-9 h.
[0014] Application of europium-based metal-organic framework-based luminescent probes in the detection of pesticides or antibiotics.
[0015] Furthermore, the pesticide is carbaryl, and the antibiotic is enrofloxacin.
[0016] Furthermore, the luminescent probe is used for fluorescence detection at an excitation wavelength of 280 nm: when detecting enrofloxacin, the main emission peak is located at 445 nm; when detecting sevin, the main emission peak is located at 364 nm.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The luminescent probe based on a europium-based metal-organic framework exemplified in the present invention can serve as a bifunctional fluorescence sensing platform to achieve specific recognition of the pesticide carbaryl and the antibiotic enrofloxacin in aqueous solution. At an excitation wavelength of 280 nm, the probe exhibits characteristic fluorescence emission and a redshift at 445 nm in a solution containing enrofloxacin; and at 364 nm in a solution containing carbaryl. The probe exhibits characteristic fluorescence emission at nm. Based on the differences in fluorescence signals after interaction with different targets, it can not only distinguish between two drugs but also lay the foundation for developing rapid visual detection methods. 2. The europium-based metal-organic framework-based luminescent probe of this invention demonstrates that, in the presence of multiple coexisting substances, the detection of enrofloxacin is not interfered with by other antibiotics (such as ceftriaxone sodium, moxifloxacin, chlortetracycline, doxycycline, tetracycline, oxytetracycline, and tetracycline hydrochloride); the detection of carbaryl is also unaffected by other pesticides (such as phoxim, paclobutrazol, carbendazim, and profenofos) and common ions (NO3). - NO2 - Mg 2+ K + CO3 2- I - ) has good anti-interference ability; 3. The luminescent probe based on europium-based metal-organic framework of the present invention has good stability and recyclability, which can reduce detection costs and make it more economical and environmentally friendly in application. Attached Figure Description
[0018] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 shows (a) Eu(phen)(5-hipa)NO3 - Asymmetric unit cell diagram of the crystal; (b) Eu(phen)(5-hipa)NO3 - Two-dimensional crystal structure diagram; Figure 2 shows the XRD characterization diagram; Figure 3 shows the Eu(phen)(5-hipa)NO3 crystal structure. -Specific detection of the fluorescence spectra of enrofloxacin and cevin in aqueous solution; Figure 4 shows (a) Eu(phen)(5-hipa)NO3 - (a) Fluorescence emission curves (0-100 μM) in solutions containing different concentrations of enrofloxacin; (b) Linear relationship between luminescence intensity at 445 nm and enrofloxacin concentration (10-50 μM); (c) Anti-interference plot; (d) Cyclic stability test plot; Figure 5 shows (a) Eu(phen)(5-hipa)NO3 - (a) Fluorescence emission curves (0-100 μM) in solutions containing different concentrations of carbaryl; (b) Linear relationship between luminescence intensity at 364 nm and carbaryl concentration (10-60 μM); (c) Anti-interference plot; (d) Cyclic stability test plot. Detailed Implementation
[0019] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.
[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0021] I. Europium-based metal-organic framework luminescent probe (Eu(phen)(5-hipa)NO3) - Preparation of Europium-based metal-organic framework luminescent probe: This embodiment provides a method for preparing a Europium-based metal-organic framework luminescent probe, which specifically includes: (1) Weighing 0.01 mmol of 1,10-phenanthroline, 0.01 mmol of 5-hydroxyisophthalic acid, and 0.02 mmol of europium nitrate hexahydrate, dissolving them in 3 mL of N,N-dimethylformamide (DMF) and 3 mL of deionized water, stirring evenly to obtain a suspension; (2) Transferring the suspension to a 25 mL polytetrafluoroethylene reaction vessel liner, and sonicating for 30 min; (3) Placing the reaction vessel in a high-temperature oven, raising the room temperature to 100°C, maintaining the temperature for 3 days, and carrying out a solvothermal reaction; (4) After the reaction is completed, naturally cooling to room temperature, picking out or filtering out the crystals in the reaction vessel through a microscope, washing three times with deionized water, and placing them in a drying oven at 60°C. (5) Dry the dried crystals by 8 hours at ℃ to obtain dried crystals; grind the dried crystals into powder using a mortar and pestle to obtain europium-based metal-organic framework materials, and place them in a desiccator for later use. The crystal structure diagram is shown in Figure 1.
[0022] The obtained product was characterized by XRD, and the test results are shown in Figure 2. The experimentally measured XRD pattern agrees well with the simulated pattern, and the characteristic diffraction peaks are in the same position, indicating that high-purity Eu(phen)(5-hipa)NO3 was successfully synthesized. - Crystalline material, free of impurity phases. II. Optical property testing of the luminescent probe.
[0023] The prepared Eu(phen)(5-hipa)NO3 - The powder was dispersed in deionized water to prepare a suspension of a certain concentration. Spectroscopic measurements were performed on a fluorescence spectrophotometer with an excitation wavelength set to 280 nm and an emission spectrum range of 350-650 nm.
[0024] The results are shown in Figure 3. Under 280 nm excitation, the luminescent probe exhibited characteristic fluorescence emission in the 350-650 nm range. When enrofloxacin was added, the main emission peak was located at 445 nm; when sevin was added, the main emission peak was located at 364 nm. III. Fluorescence Detection of Enrofloxacin by the Luminescent Probe
[0025] 1. Fluorescent titration experiment of enrofloxacin at different concentrations: Eu(phen)(5-hipa)NO3 was prepared. - The powder was dispersed in deionized water to prepare a probe solution. Enrofloxacin standard solutions of different concentrations were added to the probe solution to achieve final concentrations of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 μM. The fluorescence emission spectra of each system were measured at an excitation wavelength of 280 nm, and the fluorescence intensity at 445 nm was recorded.
[0026] As shown in Figure 4(a), the fluorescence intensity of the probe at 445 nm gradually increased with the increase of enrofloxacin concentration, indicating that enrofloxacin has a fluorescence enhancement effect on the probe.
[0027] A standard curve was plotted with enrofloxacin concentration on the x-axis and fluorescence intensity at 445 nm on the y-axis. As shown in Figure 4(b), the results indicate that the fluorescence intensity of the probe and the enrofloxacin concentration exhibit a good linear relationship within the concentration range of 10-50 μM. The linear regression equation is: Y = 0.0881X - 0.2746, with a correlation coefficient R² = 0.983, indicating that the probe can be used for the quantitative detection of enrofloxacin.
[0028] 2. Anti-interference experiment: Enrofloxacin (50 μM) and potentially coexisting interfering substances, including ceftriaxone sodium, moxifloxacin, chlortetracycline, doxycycline, tetracycline, oxytetracycline, and tetracycline hydrochloride, were added to the probe solution at a concentration of 50 μM. The fluorescence intensity at 445 nm was measured under 280 nm excitation.
[0029] As shown in Figure 4(c), compared with the system containing only enrofloxacin, the fluorescence intensity of the system did not change significantly after the addition of the above interfering substances, indicating that the probe of the present invention has good anti-interference ability for the detection of enrofloxacin.
[0030] 3. Cyclic stability test: The probe solution was mixed with enrofloxacin (50 μM), and the fluorescence intensity was measured. The probe was then recovered by centrifugation, washed three times with deionized water, redispersed, and an equal amount of enrofloxacin was added again for fluorescence measurement. The above test-wash-retest process was repeated 5 times.
[0031] As shown in Figure 4(d), after 5 cycles of use, the fluorescence intensity of the probe did not decrease significantly compared with the initial value, indicating that the probe has good recyclability and stability.
[0032] IV. Fluorescence Detection of Sevin by Luminescent Probe 1. Fluorescent Titration Experiment of Sevin at Different Concentrations The prepared Eu(phen)(5-hipa)NO3 - The powder was dispersed in deionized water to prepare a probe solution. Different concentrations of carbaryl standard solution were added to the probe solution to achieve final carbaryl concentrations of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 μM. The fluorescence emission spectra of each system were measured at an excitation wavelength of 280 nm, and the fluorescence intensity at 364 nm was recorded.
[0033] As shown in Figure 5(a), the fluorescence intensity of the probe at 364 nm gradually increased with the increase of carbaryl concentration, indicating that carbaryl has a fluorescence enhancement effect on the probe.
[0034] A standard curve was plotted with the concentration of carbaryl on the x-axis and the fluorescence intensity at 364 nm on the y-axis. As shown in Figure 5(b), the results indicate that the fluorescence intensity of the probe has a good linear relationship with the concentration of carbaryl in the concentration range of 10-60 μM. The linear regression equation is: Y = 0.0591X - 0.0278, and the correlation coefficient R² = 0.980, indicating that the probe can be used for the quantitative detection of carbaryl.
[0035] 2. Anti-interference experiment: Carbaryl (50 μM) and potentially coexisting interfering substances, including pesticides such as phoxim, paclobutrazol, carbendazim, and profenofos, as well as NO3, were added to the probe solution. - NO2 - Mg 2+ K + CO3 2- I -Common ions were used, all at a concentration of 50 μM. Fluorescence intensity at 364 nm was measured under 280 nm excitation and compared with a system containing only carbaryl.
[0036] As shown in Figure 5(c), compared with the system containing only carbaryl, the fluorescence intensity of the system did not change significantly after the addition of the above interfering substances, indicating that the probe still maintains good selectivity for the detection of carbaryl in complex systems.
[0037] 3. Cyclic stability test: The probe solution was mixed with carbaryl (50 μM), the fluorescence intensity was measured, the probe was recovered by centrifugation, washed three times with deionized water, redispersed, and an equal amount of carbaryl was added again for fluorescence measurement. The above test-wash-retest process was repeated 5 times.
[0038] As shown in Figure 5(d), after 5 cycles of use, the fluorescence intensity of the probe did not decrease significantly compared with the initial value, indicating that the probe has good recyclability and stability, can reduce detection costs, and is economical and environmentally friendly.
[0039] Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-mentioned technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-mentioned technical features or their equivalent features without departing from the inventive concept. For example, technical solutions formed by substituting the above-mentioned features with technical features disclosed in this application (but not limited to) that have similar functions.
Claims
1. A luminescent probe based on a europium-based metal-organic framework, characterized in that, The luminescent probe is a europium-based metal-organic framework material with the chemical formula Eu(phen)(5-hipa)NO3. - In this context, phen is a 1,10-phenanthroline ligand, 5-hipa is a 5-hydroxyisophthalic acid ligand, and the luminescent probe has a dinuclear Eu cluster as its metal center.
2. The luminescent probe based on a europium-based metal-organic framework according to claim 1, characterized in that, In the europium-based metal-organic framework material, the Eu ion has a nine-coordinate structure, connecting four oxygen atoms from 5-hydroxyisophthalic acid, two nitrogen atoms from 1,10-phenanthroline, and one nitrogen atom from NO3. - It has one nitrogen atom and two oxygen atoms.
3. The luminescent probe based on a europium-based metal-organic framework according to claim 1, characterized in that, The europium-based metal-organic framework material has a two-dimensional layered structure, belongs to the monoclinic crystal system, and has a space group of C2 / c.
4. A method for preparing a luminescent probe based on a europium-based metal-organic framework as described in any one of claims 1-3, characterized in that, The process includes the following steps: (1) dissolving 1,10-phenanthroline, 5-hydroxyisophthalic acid and europium nitrate hexahydrate in a mixed solvent to obtain a suspension; (2) subjecting the suspension to ultrasonic treatment and then placing it in a reaction vessel for a solvothermal reaction; (3) after the reaction is completed, allowing it to cool naturally, filtering or picking out the crystals, washing and drying to obtain europium-based metal-organic framework materials.
5. The preparation method according to claim 4, characterized in that, In step (1), the molar ratio of 1,10-phenanthroline, 5-hydroxyisophthalic acid and europium nitrate hexahydrate is 0.01 : 0.01 : 0.02; the mixed solvent is a mixture of N,N-dimethylformamide and deionized water, and the volume ratio of N,N-dimethylformamide and deionized water is 1:
1.
6. The preparation method according to claim 4, characterized in that, In step (2), the temperature of the solvothermal reaction is 100 °C and the time is 3 days.
7. The preparation method according to claim 4, characterized in that, In step (3), the drying conditions are 60 °C for 6-9 h.
8. The luminescent probe based on europium-based metal-organic framework as described in any one of claims 1-3, or the luminescent probe based on europium-based metal-organic framework prepared by the preparation method described in any one of claims 4-7, for the detection of pesticides or antibiotics.
9. The application according to claim 8, characterized in that, The pesticide is carbaryl, and the antibiotic is enrofloxacin.
10. The application according to claim 8, characterized in that, The luminescent probe was used for fluorescence detection at an excitation wavelength of 280 nm: when detecting enrofloxacin, the main emission peak was located at 445 nm; when detecting seviin, the main emission peak was located at 364 nm.