A novel multifunctional MOF on MOF gel material and its preparation method and application

Abstract

The present invention discloses a novel multifunctional MOF on MOF gel material and its preparation method and application, named FCZE, the gel material is a core-shell structure, with a bimetallic organic framework MOF as the core, a Uio-66 / Eu layer as the shell, the bimetallic is Fe and Cu, Uio-66 and Eu are coordinated and connected in the Uio-66 / Eu layer, and the bimetallic organic framework MOF is first prepared using copper salt, iron salt and trimesic acid; then pyromellitic acid, zirconium salt and europium salt are added to prepare the MOF on MOF gel material. The MOF on MOF gel material prepared by the present invention integrates different types of signal conversion mechanisms (fluorescence and colorimetry) through a unique composite structure design, and realizes rapid and sensitive detection of CTC, CIP and D-PA at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials and their analytical applications, and in particular relates to a new multifunctional MOF-onMOF gel material and a preparation method and application thereof. Background Art

[0002] Since their discovery in the early 20th century, antibiotics have greatly improved the treatment of human and animal diseases, effectively inhibited bacterial infections, and saved countless lives. However, the widespread use of antibiotics is also accompanied by some problems that cannot be ignored, the most prominent of which is antibiotic residues. After antibiotics are ingested by humans or animals, the incompletely metabolized part will enter the natural environment such as water bodies and soil through excretion, thereby affecting water sources, food chains and even the entire ecosystem, causing environmental pollution, and may promote the generation and spread of drug-resistant bacteria, posing a serious threat to public health.

[0003] Traditional methods for detecting antibiotic residues mainly include high performance liquid chromatography (HPLC), gas chromatography (GC) and mass spectrometry (MS) combined technologies, such as LC-MS / MS and GC-MS, which are currently the "gold standard" for detecting antibiotic residues and have high specificity and high sensitivity. Although these methods have high accuracy, they generally have problems such as long detection cycles, high costs, strong dependence on instruments and equipment, and complex operating procedures, which limit their application in daily monitoring and on-site rapid screening. Especially in scenarios such as food safety supervision and environmental monitoring, fast, simple, and cost-effective detection technologies are particularly important.

[0004] In recent years, the development of various new sensor technologies and nanomaterials has brought new opportunities for antibiotic residue detection. Metal-Organic Frameworks (MOFs), as an emerging porous material, provide the possibility of building a highly sensitive and highly selective detection platform due to its highly ordered structure, adjustable pore size, high specific surface area and rich enzyme-like activity. In addition, lanthanide metals (such as europium (Eu), terbium (Tb), samarium (Sm), etc.) combined with MOF materials have shown advantages such as high sensitivity, high selectivity, long-life fluorescence and good stability in antibiotic detection, providing strong support for the development of new and efficient antibiotic residue detection technology. Although the application of MOF and lanthanide MOF in the field of antibiotic sensing has been reported, there are still challenges in multi-mode integrated detection and rapid quantitative analysis of antibiotic residues in actual samples (such as water samples, milk). In particular, how to design and synthesize a multifunctional MOF material that has the ability to efficiently identify specific antibiotics and can integrate multiple detection modes has become the focus and difficulty of current research. In addition, how to simplify the testing process to make it more in line with the needs of rapid on-site testing is also the key to technological development. Summary of the invention

[0005] In order to overcome the problems in the prior art, the present invention provides a novel multifunctional MOF on MOF gel material and a preparation method and application thereof. Through a unique composite structure design, different types of signal conversion mechanisms (fluorescence and colorimetry) are integrated to achieve rapid and sensitive detection of CTC (chlortetracycline), CIP (ciprofloxacin) and D-PA (D-penicillamine).

[0006] In order to solve the above technical problems, the technical solutions proposed by the present invention are as follows:

[0007] The present invention provides a novel multifunctional MOF on MOF gel material. The gel material is a core-shell structure. The gel material uses a bimetallic organic framework MOF as a core and a Uio-66 / Eu layer as an outer shell. The bimetallic is Fe and Cu. In the Uio-66 / Eu layer, Uio-66 is coordinated and connected with Eu.

[0008] In the present invention, the MOF on MOF gel material is named FCZE. FCZE has MOF (Fe-Cu) as the core and has enhanced peroxidase-like activity compared to MOF (Fe). Uio-66 in the shell can provide coordination sites for lanthanide metals (Eu) and greatly enhance the fluorescence emission intensity of Eu through the "antenna effect".

[0009] Based on the same technical concept, the present invention also provides a method for preparing the novel multifunctional MOF on MOF gel material, comprising the following steps:

[0010] S1. Dissolve copper salt, iron salt and trimesic acid in a solvent, stir evenly and heat to prepare a bimetallic organic framework MOF.

[0011] S2. Dissolve the bimetallic organic framework MOF and polyvinylpyrrolidone, add pyromellitic acid and zirconium salt, and use the solvothermal method to synthesize the gel MOF (Fe-Cu)@UiO-66-(COOH)2.

[0012] S3. Mix MOF(Fe-Cu)@UiO-66-(COOH)2 and europium salt in ethanol evenly, stir for half reaction and then wash to obtain a new multifunctional MOF on MOF gel material.

[0013] In the present invention, trimesic acid is used as a ligand of iron and copper, and iron and copper coordinate with the carboxyl group above to form an organic framework MOF. The polar group of polyvinylpyrrolidone has a high affinity for metal ions. Polyvinylpyrrolidone is wrapped around the metal cation through coordination. Zr 4+ was adsorbed onto the Fe-Cu MOF. Then, the pyromellitic acid ligand was combined with Zr4+ Coordinate on the surface and grow to form a MOF on MOF hybrid structure.

[0014] As an optional embodiment, in the preparation method provided by the present invention, in step S1, Fe 3+ and Cu 2+ The molar ratio (2-4):1.

[0015] Furthermore, it is preferably 4:1.

[0016] As an optional embodiment, in the preparation method provided by the present invention, in step S2, the mass ratio of the metal organic framework MOF, pyromellitic acid and zirconium salt is (0.5-2): (5-10): (4-8).

[0017] As an optional embodiment, in the preparation method provided by the present invention, in step S3, the mass ratio of MOF(Fe-Cu)@UiO-66-(COOH)2 and europium salt is (0.5-2):(5-10).

[0018] Based on the same technical concept, the present invention also provides the use of the above-mentioned novel multifunctional MOF on MOF gel material or the novel multifunctional MOF on MOF gel material prepared by the above-mentioned preparation method in the simultaneous detection of chlortetracycline, ciprofloxacin and D-penicillamine in samples.

[0019] As an optional embodiment, in the application provided by the present invention, when chlortetracycline, ciprofloxacin and D-penicillamine are detected simultaneously, chlortetracycline and ciprofloxacin in the sample are first detected by fluorescence method, and then D-penicillamine in the sample is detected by colorimetry.

[0020] As an optional embodiment, in the application provided by the present invention, the D-penicillamine in the sample is detected by colorimetry, and the absorbance value of oxidized TMB (3,3',5,5'-tetramethylbenzidine) at 652 nm is measured by a UV-visible spectrophotometer to achieve quantitative detection of D-PA.

[0021] Based on the same technical concept, the present invention also provides a method for detecting CTC, CIP or D-PA in a sample using a smart phone, comprising the following steps: adding the above-mentioned novel multifunctional MOF on MOF gel material or the novel multifunctional MOF on MOF gel material prepared by the above-mentioned preparation method to a transparent well plate, and then adding a solution containing CTC, CIP or D-PA. After the reaction, the well plate is placed under a 312nm ultraviolet lamp, and pictures of MOF on MOF gels with different antibiotic dosages are taken by a smart phone, and RGB parameter information is identified by a mobile phone app to quantitatively analyze the antibiotics.

[0022] As an optional embodiment, in the detection method provided by the present invention, the RGB of the captured image is identified by the mobile phone software ColorGrab, a standard curve between the chromaticity value and the concentration of the antibiotic CTC, CIP or D-PA is established, and CTC, CIP or D-PA is quantitatively detected.

[0023] The detection principle of the present invention is as follows:

[0024] When CTC is present in the sample, the fluorescence of Eu at 615 nm is quenched, so a fluorescence spectrophotometer can be used to quantitatively detect CTC based on the relationship between CTC concentration and fluorescence intensity. When CIP is present in the sample, the fluorescence of Eu at 615 nm is also quenched, but CIP itself has autofluorescence emission at 448 nm, so a fluorescence spectrophotometer can be used to measure the ratio of the fluorescence intensity at 488 nm to the fluorescence intensity at 615 nm to perform ratio fluorescence detection on CIP, thereby reducing the false positive rate of CIP detection. When D-PA is present in the sample, the catalytic oxidation reaction of MOF on MOF gel for H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB) is inhibited, so that TMB does not change color. The absorbance value of oxidized TMB at 652 nm can be measured by UV-visible spectrophotometer to achieve quantitative detection of D-PA.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) Compared with MOF (Fe-Cu) or Uio-66 / Eu alone, the MOF on MOF gel material prepared by the present invention can simultaneously exhibit peroxidase-like activity and significant lanthanide metal fluorescence emission. Its peroxidase-mimicking enzyme activity and fluorescence emission characteristics can be used to detect a variety of targets, such as the quantitative detection of chlortetracycline, ciprofloxacin and D-penicillamine in water samples and milk in the fields of food safety and biomedicine.

[0027] (2) A multifunctional gel detection platform integrating fluorescence detection, ratiometric fluorescence detection and colorimetric detection is provided. Through a multi-mode detection strategy, the sensitivity and accuracy of detection are significantly improved. By using a fluorescence spectrophotometer and a UV-visible spectrophotometer, quantitative detection of CTC, CIP and D-PA in water samples and milk can be achieved respectively. The operation is simple, fast, low-cost and highly sensitive.

[0028] (3) The visualized MOF on MOF gel (FCZE) of the present invention can be used to drop the sample to be tested directly onto the gel for reaction, and then take a photo with a mobile phone under ultraviolet light to read the RGB value of the test paper. Only a small amount of sample is needed to quickly, conveniently and accurately perform quantitative detection of the target in water samples and milk. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 Performance results of FCZE with a Fe / Cu ratio of 4:1 prepared in Example 1, where (A) is a SEM image of MOF (Fe-Cu), (B) is a SEM image of FCZE, and (CH) is an elemental mapping of O, Fe, Cu, Zr, and Eu;

[0031] Figure 2 TEM images of different scales of FCZE with a Fe / Cu ratio of 4:1 prepared in Example 1;

[0032] Figure 3 Activity comparison results of MOF (Fe-Cu) materials prepared with different Fe / Cu ratios prepared in Example 1;

[0033] Figure 4 The fluorescence spectrum and linear relationship diagram of chlortetracycline detected by the FCZE gel material with a Fe / Cu ratio of 4:1 prepared in Example 1;

[0034] Figure 5 The fluorescence spectrum and linear relationship diagram of ciprofloxacin detected by the FCZE gel material with a Fe / Cu ratio of 4:1 prepared in Example 1;

[0035] Figure 6 The UV-visible spectrum and linear relationship diagram of the FCZE gel material with a Fe / Cu ratio of 4:1 prepared in Example 1 for detecting penicillamine;

[0036] Figure 7 Actual picture of the gel used to assist in the detection of chlortetracycline, ciprofloxacin and penicillamine using a smartphone. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0038] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0039] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0040] Example 1

[0041] The synthesis of MOF on MOF gel includes the following steps:

[0042] (1) Synthesis of MOF (Fe-Cu): Copper nitrate trihydrate (0.25 mmol, 42.6 mg), ferric chloride hexahydrate (1 mmol, 270.3 mg) and trimesic acid (1 mmol, 210.14 mg) were dissolved in N,N-dimethylformamide (7 mL). 3+ / Cu 2+ The molar ratio of Cu to Fe-Cu was 1:0, 4:1, 2:1, 4:3, 1:1, 4:5 to synthesize bimetallic MOF (Fe-Cu) with different Cu doping. The mixed solution was magnetically stirred for 30 minutes at room temperature, ultrasonicated for 20 minutes, and then transferred to a 50 mL reactor, reacted at 150 ° C for 24 hours, cooled to room temperature, and the reddish brown product was centrifuged at 8000 rpm for 10 min. Washed with N, N-dimethylformamide and anhydrous ethanol three times, respectively. Subsequently, the precipitate was dissolved in 50 mL N, N-dimethylformamide and refluxed at 153 ° C for 5 hours. After the solution was cooled, the dark brown-red solution was transferred to a centrifuge tube and centrifuged at 8000 rpm for 10 min, and washed with N, N-dimethylformamide and anhydrous ethanol three times, respectively.

[0043] (2) Synthesis of MOF(Fe-Cu)@UiO-66-(COOH)2 by solvothermal method: Weigh 150 mg Fe 3+ / Cu 2+MOF (Fe-Cu) with a molar ratio of (4:1) and 100 mg polyvinyl pyrrolidone were added to 10 mL N, N-dimethylformamide and magnetically stirred continuously for 12 h at room temperature to form a uniform reddish brown solution A. Accurately weigh pyromellitic acid (1.38 g, 5.4 mmol) and zirconium chloride (0.92 g, 4.0 mmol), add 30 mL ultrapure water to obtain solution B. Then, solution A was transferred to the off-white solution B and magnetically stirred for 2 h to form a uniform dark red solution. The solution was transferred to a reactor and heated at 110 ° C for 24 h. After cooling to room temperature, the gel product was centrifuged at 8000 rpm for 5 min, and the supernatant was discarded to obtain a light red gel solid, which was washed 3 times with ultrapure water. The product obtained after washing was dispersed in 40 mL ultrapure water and refluxed at 110°C for 16 h. After the solution was cooled, it was centrifuged at 8000 rpm for 5 min. The precipitate was washed three times with ultrapure water and anhydrous ethanol to obtain a light red gel.

[0044] (3) MOF(Fe-Cu)@UiO-66-(COOH)2 (0.30 g) and europium nitrate hexahydrate (2.230 g, 5.0 mmol) were mixed in 30 mL of ethanol and stirred at 80 °C for 24 h. After cooling to room temperature, the mixture was centrifuged at 8000 rpm for 5 min. The light red precipitate was washed three times with water and ethanol respectively. The final gel-like material was MOF on MOF gel, named FCZE.

[0045] Example 2

[0046] (1) Synthesis of MOF (Fe-Cu): Copper nitrate trihydrate (0.25 mmol, 42.6 mg), ferric chloride hexahydrate (1 mmol, 270.3 mg) and trimesic acid (1 mmol, 210.14 mg) were dissolved in N,N-dimethylformamide (7 mL). 3+ / Cu 2+ The molar ratio of Cu to Cu was 4:1 to synthesize Cu-doped bimetallic MOF (Fe-Cu). The mixed solution was magnetically stirred at room temperature for 30 minutes, ultrasonicated for 20 minutes, and then transferred to a 50 mL reactor and reacted at 150 ° C for 24 hours. After cooling to room temperature, the reddish-brown product was centrifuged at 8000 rpm for 10 min. Washed 3 times with N, N-dimethylformamide and anhydrous ethanol respectively. Subsequently, the precipitate was dissolved in 50 mL N, N-dimethylformamide and refluxed at 153 ° C for 5 h. After the solution was cooled, the dark brown-red solution was transferred to a centrifuge tube and centrifuged at 8000 rpm for 10 min, and washed 3 times with N, N-dimethylformamide and anhydrous ethanol respectively.

[0047] (2) Synthesis of MOF(Fe-Cu)@UiO-66-(COOH)2 by solvothermal method: Weigh 75 mg Fe 3+ / Cu 2+ MOF (Fe-Cu) with a molar ratio of (4:1) and 100 mg of polyvinyl pyrrolidone were added to 10 mL of N,N-dimethylformamide and magnetically stirred continuously for 12 h at room temperature to form a uniform reddish brown solution A. Accurately weigh pyromellitic acid (0.375 g, 1.48 mmol) and zirconium chloride (0.30 g, 1.29 mmol), add 30 mL of ultrapure water to obtain solution B. Then, solution A was transferred to the off-white solution B and magnetically stirred for 2 h to form a uniform dark red solution. The solution was transferred to a reactor and heated at 110 ° C for 24 h. After cooling to room temperature, the gel product was centrifuged at 8000 rpm for 5 min, and the supernatant was discarded to obtain a light red gel solid, which was washed 3 times with ultrapure water. The product obtained after washing was dispersed in 40 mL ultrapure water and refluxed at 110°C for 16 h. After the solution was cooled, it was centrifuged at 8000 rpm for 5 min. The precipitate was washed three times with ultrapure water and anhydrous ethanol to obtain a light red gel.

[0048] (3) MOF(Fe-Cu)@UiO-66-(COOH)2 (0.15 g) and europium nitrate hexahydrate (1.50 g, 3.36 mmol) were mixed in 30 mL of ethanol and stirred at 80 °C for 24 h. After cooling to room temperature, the mixture was centrifuged at 8000 rpm for 5 min. The light red precipitate was washed three times with water and ethanol respectively. The final gel-like material was MOF on MOF gel, named FCZE.

[0049] Example 3

[0050] (1) Synthesis of MOF (Fe-Cu): Copper nitrate trihydrate (0.25 mmol, 42.6 mg), ferric chloride hexahydrate (1 mmol, 270.3 mg) and trimesic acid (1 mmol, 210.14 mg) were dissolved in N,N-dimethylformamide (7 mL). 3+ / Cu 2+The molar ratio of Cu to Cu was 4:1 to synthesize Cu-doped bimetallic MOF (Fe-Cu). The mixed solution was magnetically stirred at room temperature for 30 minutes, ultrasonicated for 20 minutes, and then transferred to a 50 mL reactor and reacted at 150 ° C for 24 hours. After cooling to room temperature, the reddish-brown product was centrifuged at 8000 rpm for 10 min. Washed 3 times with N, N-dimethylformamide and anhydrous ethanol respectively. Subsequently, the precipitate was dissolved in 50 mL N, N-dimethylformamide and refluxed at 153 ° C for 5 h. After the solution was cooled, the dark brown-red solution was transferred to a centrifuge tube and centrifuged at 8000 rpm for 10 min, and washed 3 times with N, N-dimethylformamide and anhydrous ethanol respectively.

[0051] (2) Synthesis of MOF(Fe-Cu)@UiO-66-(COOH)2 by solvothermal method: Weigh 150 mg Fe 3+ / Cu 2+ MOF (Fe-Cu) with a molar ratio of (4:1) and 100 mg of polyvinyl pyrrolidone were added to 10 mL of N,N-dimethylformamide and stirred continuously under magnetic force for 12 h at room temperature to form a uniform red-brown solution A. Accurately weigh pyromellitic acid (0.75 g, 2.95 mmol) and zirconium chloride (0.0.6 g, 2.57 mmol), add 30 mL of ultrapure water to obtain solution B. Then, solution A was transferred to the off-white solution B and stirred magnetically for 2 h to form a uniform dark red solution. The solution was transferred to a reactor and heated at 110 ° C for 24 h. After cooling to room temperature, the gel product was centrifuged at 8000 rpm for 5 min, and the supernatant was discarded to obtain a light red gel solid, which was washed 3 times with ultrapure water. The product obtained after washing was dispersed in 40 mL ultrapure water and refluxed at 110°C for 16 h. After the solution was cooled, it was centrifuged at 8000 rpm for 5 min. The precipitate was washed three times with ultrapure water and anhydrous ethanol to obtain a light red gel.

[0052] (3) MOF(Fe-Cu)@UiO-66-(COOH)2 (0.30 g) and europium nitrate hexahydrate (1.50 g, 3.36 mmol) were mixed in 30 mL of ethanol and stirred at 80 °C for 24 h. After cooling to room temperature, the mixture was centrifuged at 8000 rpm for 5 min. The light red precipitate was washed three times with water and ethanol respectively. The final gel-like material was MOF on MOF gel, named FCZE.

[0053] The MOF on MOF gel material prepared in Example 1 was tested for activity, and the results were as follows: Figure 3As shown in the figure, the Fe / Cu ratios of 4:1 and 2:1 have better effects, and the FCZE gel material with a ratio of 4:1 has the highest activity. The FCZE gel material with a Fe / Cu ratio of 4:1 was tested, and the results are as follows Figure 1 As shown, Figure 1 A is the SEM image of MOF (Fe-Cu), B is the SEM image of FCZE, and CH is the element mapping of O, Fe, Cu, Zr, and Eu.

[0054] Example 4

[0055] Application of FCZE gel

[0056] 1. Fluorescence detection of CTC and CIP

[0057] The FCZE gel material with a Fe / Cu ratio of 4:1 prepared in Example 1 was added to ultrapure water to form a 10 mg / mL suspension. At room temperature, 10 μL of MOF onMOF gel suspension was added to 1970 μL of Tris-HCl buffer (pH 6, 10 mM), and then 20 μL of CTC solution (ensuring a final concentration of 0.5 nM to 200 nM) or sample solution was added. After reacting at room temperature for 5 min, a molecular fluorescence spectrometer was used to record the fluorescence spectrum of 550-750 nm at an excitation wavelength of 300 nm, and the CTC concentration was quantitatively analyzed using the fluorescence emission intensity at 615 nm. Each measurement was repeated 3 times. The results are shown in Figure 2. Figure 4 As shown, from Figure 4 It can be seen from the fluorescence spectrum that the fluorescence intensity decreases with the increase of CTC concentration, and in the range of 0.5 nM to 200 nM, the fluorescence intensity is linearly related to the CTC concentration. The linear equation is F=-4962.2C+2056846.9 (r=0.999), and the calculated detection limit is 0.43 nM, indicating that this method has a low detection limit for detecting CTC.

[0058] For CIP detection, add the same volume of CIP solution (ensuring the final concentration is 2.5 nM to 1000 nM) or sample solution, react at room temperature for 5 min, and use a molecular fluorescence spectrometer to record the fluorescence spectrum of 550-750 nm at an excitation wavelength of 300 nm. The standard curve of CIP concentration is established by the fluorescence intensity ratio at 448 nm and 615 nm. Each measurement is repeated 3 times. The results are shown in Figure 5 As shown, from Figure 5 It can be seen from the fluorescence spectrum that the fluorescence intensity at 615 nm decreases with the increase of CIP concentration, and the fluorescence intensity at 448 nm increases with the increase of CIP concentration. In the range of 2.5 nM to 100 nM, F 448 / F615 The value is linearly related to the CIP concentration, and the linear equation is F 448 / F 615 =0.00065C+0.028 (r=0.998), and the detection limit was calculated to be 1.2 nM, indicating that this method has a low detection limit for detecting CIP.

[0059] 2. Colorimetric detection of D-PA

[0060] 100 μL TMB (10 mM), 100 μL H2O2 (10 mM), 20 μL MOF on MOF gel solution (10 mg / mL) and 1 mL acetic acid-sodium acetate buffer solution (pH 4, 0.1 M) were added to a 5 mL centrifuge tube, followed by the addition of freshly prepared D-PA solution of different concentrations (final concentration of 12.5 nM-2000 nM) or sample solution, and finally ultrapure water to a total volume of 2 mL. After incubation at 40°C for 5 min, the UV absorption spectrum at 500-800 nm was measured using a UV-visible spectrophotometer. The results are shown in Figure 2. Figure 6 As shown, Figure 6 From the UV-visible spectrum shown, it can be observed that the absorbance at 652 nm decreases with the increase of D-PA concentration, and in the range of 12.5 nM to 1000 nM, the absorbance value is linearly related to the D-PA concentration. The linear equation is A=-0.0006C+1.53 (r=0.997). The detection limit is calculated to be 8.66 nM, which can detect lower concentrations of D-PA.

[0061] 3. Detection of CTC, CIP and D-PA based on FCZE gel smartphone

[0062] CTC / CIP fluorescence visualization detection: 10 μL Tris-HCl (pH 7, 10 mM) and 20 μL CTC / CIP of different concentrations were added to a 24-well plate containing FCZE gel, with the final concentration of CTC (01, 0.2, 0.5, 0.8, 1, 5, 10, 20, 40, 60, 80, 100 μM); the final concentration of CIP (0.02, 0.04, 0.06, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 5, 10 μM). After reacting for 5 minutes, the 24-well plate was placed in a 312 nm UV light box, and a photo was taken with a smartphone, and RGB (red, green, blue) was identified through a mobile phone software (Color Grab). A standard curve between the colorimetric value and the antibiotic concentration was established to quantitatively detect CTC / CIP. The results are shown in Figure 7As shown, CTC has a linear relationship with the G / R value in the concentration range of 1.0-80.0 μM, and the linear equation is: G / R=0.0095C+0.19 (r=0.995) with a detection limit of 0.71 μM. CIP has a linear relationship with the B / R value in the concentration range of 0.04-0.4 μM, and the linear equation is: B / R=0.6555C+0.82 (r=0.995) with a detection limit of 0.036 μM.

[0063] D-PA colorimetric visualization detection: 10 μL HAC-NaAC (pH4, 1 M), 20 μL D-PA of different concentrations (final concentrations of 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 30 μM), 10 μL TMB (2.5 mM) and 10 μL H2O2 (5 mM) were added to a 24-well plate containing FCZE gel. After 5 minutes of reaction, take a photo with a smartphone and identify RGB (red, green, blue) through the mobile phone software (ColorGrab). A standard curve between the colorimetric value and the antibiotic concentration was established to quantitatively detect D-PA. The results are shown in Figure 7 As shown, in the concentration range of 0.5-6 μM, it is linearly related to the G / B value, the linear equation is: G / B=0.0174C +0.81 (r=0.997), and the detection limit is: 0.13 μM.

[0064] The above experiments verified that the FCZE-based smartphone-assisted visual sensor has good on-site detection effects for CTC, CIP and D-PA, and can provide high-sensitivity, easy-to-operate and low-cost on-site rapid detection support for food safety, public health and drug monitoring.

[0065] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for preparing a novel multifunctional MOF on MOF gel material, characterized in that: The following steps are involved: S1, dissolving copper salt, iron salt and trimesic acid in a solvent, stirring evenly and heating to prepare a bimetallic organic framework MOF; S2, dissolving bimetallic organic framework MOF and polyvinylpyrrolidone, adding pyromellitic acid and zirconium salt, and synthesizing gel MOF (Fe-Cu)@UiO-66-(COOH)2 by solvothermal method; S3. Mix MOF(Fe-Cu)@UiO-66-(COOH)2 and europium salt in ethanol evenly, stir for half reaction and then wash to obtain a new multifunctional MOF on MOF gel material.

2. The method for preparing the novel multifunctional MOF on MOF gel material according to claim 1, characterized in that: In step S1, Fe 3+ and Cu 2+ The molar ratio (2-4):

1.

3. The method for preparing the novel multifunctional MOF on MOF gel material according to claim 1, characterized in that: In step S2, the mass ratio of the metal organic framework MOF, pyromellitic acid and zirconium salt is (0.5-2): (5-10): (4-8).

4. The method for preparing the novel multifunctional MOF on MOF gel material according to claim 1, characterized in that: In step S3, the mass ratio of MOF(Fe-Cu)@UiO-66-(COOH)2 and europium salt is (0.5-2):(5-10).

5. The method for preparing the novel multifunctional MOF on MOF gel material according to claim 1, characterized in that: The gel material is a core-shell structure, wherein the gel material has a bimetallic organic framework MOF as a core and a Uio-66 / Eu layer as an outer shell, the bimetallic is Fe and Cu, and Uio-66 and Eu in the Uio-66 / Eu layer are coordinated and connected.

6. Application of the novel multifunctional MOF on MOF gel material prepared by the preparation method according to any one of claims 1 to 5 in the simultaneous detection of chlortetracycline, ciprofloxacin and D-penicillamine in a sample.

7. The use according to claim 6, characterized in that: When chlortetracycline, ciprofloxacin and D-penicillamine are detected simultaneously, chlortetracycline and ciprofloxacin in the sample are first detected by fluorescence method, and then D-penicillamine in the sample is detected by colorimetry.

8. The use according to claim 7, characterized in that: The D-penicillamine in the sample was detected by colorimetry, and the quantitative detection of D-PA was achieved by measuring the absorbance of oxidized 3,3',5,5'-tetramethylbenzidine at 652 nm using a UV-visible spectrophotometer.

9. A method for detecting chlortetracycline, ciprofloxacin or D-penicillamine in a sample using a smart phone, characterized in that: The method comprises the following steps: adding the novel multifunctional MOF onMOF gel material prepared by the preparation method according to any one of claims 1 to 5 into a transparent well plate, then adding a solution containing chlortetracycline, ciprofloxacin or D-penicillamine, placing the well plate under a 312nm ultraviolet lamp after the reaction, taking pictures of the MOF on MOF gel with different antibiotic dosages through a smart phone, using a mobile phone app to identify RGB parameter information, and performing quantitative analysis of the antibiotics.

10. The method for detecting chlortetracycline, ciprofloxacin or D-penicillamine in a sample using a smart phone according to claim 9, characterized in that: The RGB of the captured image was identified by the mobile phone software Color Grab, and a standard curve was established between the chromaticity value and the concentration of the antibiotics chlortetracycline, ciprofloxacin or D-penicillamine, so as to quantitatively detect chlortetracycline, ciprofloxacin or D-penicillamine.

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