Magnetic microparticle metal-organic framework material and its application in veterinary drug residues in animal-derived food

Abstract

The application discloses a kind of magnetic microparticle metal organic framework material and its application in veterinary drug residue in animal-derived food.The magnetic microparticle metal organic framework material is the composite of ZIF-8 metal organic framework material with (011) crystal face and nano magnetic particle, the particle size of magnetic microparticle metal organic framework material is 450-550nm, the (011) crystal face of ZIF-8 metal organic framework material forms rhombic dodecahedron, and the particle size is 400-500nm;The particle size of nano magnetic particle is 20-50nm, and nano magnetic particle is uniformly distributed in the edge position and crystal face central position of the rhombic dodecahedron of ZIF-8 metal organic framework material.The magnetic microparticle metal organic framework material of the application has good selective adsorption to veterinary small molecule compounds, and can be used in the detection of veterinary drug residue in animal-derived solid sample, and after rapid separation and enrichment by magnetic microparticle metal organic framework material, it can be directly detected by ultra-high performance liquid chromatography-mass spectrometry.

Description

Technical Field

[0001] This invention relates to a magnetic microparticle metal-organic framework material and its application in veterinary drug residues in animal-derived foods, belonging to the field of novel nanomaterials technology. Background Technology

[0002] In veterinary drug residue detection, 60% of the time is spent on pretreatment, which is also the most time-consuming and error-prone step in residue analysis. The performance of the pretreatment materials directly affects the residue analysis results. Metal-organic frameworks (MOFs) are mesh-like porous framework materials formed by the self-assembly of inorganic metal ions (clusters) and organic ligands through coordination bonds. Their structure has extremely high porosity (free volume up to 90%) and a huge specific surface area (over 6000 m²). 2 The MOF framework structure offers advantages such as the ability to synthesize different spatial configurations and tunable pore sizes by altering organic ligands, resulting in functional diversity and structural tunability. MOF materials typically exhibit good chemical and structural stability, thus possessing excellent adsorption, catalytic, and chiral separation properties. They are now widely used for various gases (H2, CO2, CH4) and heavy metal ions (Cd). 2+ Pb 2+ Hg 2+ Adsorption and removal of pesticides and veterinary drugs. Through magnetic modification, magnetic materials such as iron oxides (Fe3O4 / Fe2O3) can be combined with MOFs to form magnetic MOFs, which can rapidly separate and enrich the adsorbed analytes and impurities in a short time, greatly simplifying the pretreatment process.

[0003] Quinolones (QNs) are a class of compounds with a parent ring structure of 1,4-dihydro-4-oxopyridine-3-carboxylic acid. The primary target of QNs is DNA gyrase (topoisomerase II). By inhibiting the GyrA subunit of gyrase, they alter the topological structure of bacterial chromosomal / plasmid DNA, thereby inhibiting bacterial nucleic acid replication and transcription, and interfering with protein synthesis. This disrupts bacterial proliferation, achieving an antibacterial effect. QNs primarily target Gram-negative bacteria, but also have strong bactericidal activity against some Gram-positive bacteria and mycoplasma. These QNs drugs have strong tissue penetration capabilities and low toxicity to the body. In my country, fluoroquinolone antibiotics such as norfloxacin, ofloxacin, and ciprofloxacin have been approved for use in animal husbandry from human clinical settings. Currently, norfloxacin, ofloxacin, and ciprofloxacin are widely used in livestock and poultry farming.

[0004] As a solid matrix, poultry egg samples have complex compositions, and the effectiveness of pretreatment separation and enrichment of chloramphenicol in these samples directly affects the sensitivity and accuracy of detection methods. Magnetic solid-phase enrichment and separation methods combine the speed and simplicity of magnetic separation with the high efficiency of solid-phase extraction. Currently, it is an ideal choice for the rapid separation, extraction, and enrichment of small molecule veterinary drug compounds in solid samples. Therefore, it is necessary to provide magnetic materials suitable for detecting veterinary drug residues in animal-derived solid samples. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetic microparticle metal-organic framework material that has good selective adsorption properties for small molecule veterinary drug compounds. It can be used for the detection of veterinary drug residues in animal-derived solid samples. After rapid separation and enrichment by the magnetic microparticle metal-organic framework material, it can be directly detected by ultra-high performance liquid chromatography-mass spectrometry.

[0006] The magnetic microparticle metal-organic framework material (mZIF-8) provided by the present invention is a composite of ZIF-8 metal-organic framework material with (011) crystal plane and nano-magnetic particles.

[0007] The magnetic microparticle metal-organic framework material has a particle size of 450–550 nm.

[0008] The (011) crystal plane of the ZIF-8 metal-organic framework material forms a rhombic dodecahedron with a particle size of 400-500 nm.

[0009] The nanomagnetic particles have a particle size of 20-50 nm and are uniformly distributed at the edges and center of the crystal faces of the rhombic dodecahedron of the ZIF-8 metal-organic framework material.

[0010] The magnetic nanoparticles are positively charged Fe3O4 magnetic nanoparticles.

[0011] This invention provides a method for the preparation of the distributed assembly of the magnetic microparticle metal-organic framework material. First, nanomagnetic particles are prepared by coprecipitation, then dispersed in pure water, and further added with organic ligands of MOFs (2-MI) and zinc nitrate. The mZIF-8 product is finally obtained through aqueous self-assembly.

[0012] Specifically, it includes the following steps:

[0013] The nanomagnetic particles are dispersed in an aqueous solution of 2-methylimidazole and zinc nitrate and then self-assembled to obtain the nanomagnetic particles.

[0014] The preparation method of the nanomagnetic particles includes the following steps:

[0015] FeCl3·6H2O and FeCl2·4H2O were crystallized at high temperature in water under an inert atmosphere, and NH3·H2O was added.

[0016] The high-temperature crystallization is carried out at a temperature of 80–100°C for 3–5 hours.

[0017] The molar ratio of 2-methylimidazole to zinc nitrate is 60-80:1;

[0018] In the aqueous solution of the nanomagnetic particles, the concentration of the nanomagnetic particles is 5–25 mg / mL;

[0019] The mass ratio of 2-methylimidazole to the nanomagnetic particles is 1.4 g: 5–25 mg.

[0020] The magnetic microparticle metal-organic framework material provided by this invention can be used for the detection of veterinary drug residues in animal-derived solid samples. The veterinary drug small molecule compounds that can be selectively adsorbed include: quinolones (enrofloxacin, ofloxacin, norfloxacin, ciprofloxacin), tetracyclines (tetracycline, chlortetracycline, oxytetracycline), and chloramphenicol.

[0021] The animal-derived solid samples are edible muscle tissue, dairy products, or egg products from animals.

[0022] During testing, the amount of the magnetic microparticle metal-organic framework material in the sample is 1.0–5.0 mg / g, preferably 5.0 mg / g; the adsorption time is 15–30 min, preferably 20 min in water and 30 min in milk; the pH of the adsorption solution is 6–8, preferably 7; the adsorption effect of mZIF-8 is not affected within the salt ion concentration range of 0–0.5 mol / L.

[0023] The magnetic microparticle metal-organic framework (mZIF-8) pretreatment material of this invention, after adsorbing small molecule compounds of veterinary drugs, can be directly subjected to high-precision quantitative detection by mass spectrometry (LC-MS / MS) after rapid magnetic separation and elution.

[0024] The present invention has the following beneficial technical effects:

[0025] (1) The metal-organic framework (ZIF-8) in the magnetic adsorption material of the present invention is a (011) crystal plane ZIF-8 metal-organic framework material, wherein ZIF-8 has a specific rhombic dodecahedral grain structure (particle size: 400-500nm), and mZIF-8 has good selective adsorption for quinolone antibiotics (norfloxacin and ciprofloxacin) and chloramphenicol (the saturated adsorption capacity for norfloxacin, ciprofloxacin and chloramphenicol is as high as 76.5, 233.12 and 67.18 mg / g, respectively). This performance can fully guarantee that mZIF-8 can be used as a highly efficient antibiotic residue adsorbent in the field of animal food safety testing.

[0026] (2) The mZIF-8 nanomagnetic particles (particle size: 20-50nm) of the present invention are specifically distributed at the edge positions and the center positions of the crystal faces in the ZIF-8 rhombic dodecahedral grains. This can effectively ensure that the prepared mZIF-8 has good superparamagnetism, while not affecting the adsorption performance of ZIF-8 on the target antibiotics. This shows that mZIF-8 is an antibiotic residue pretreatment material with efficient selective adsorption, rapid enrichment and magnetic separation, which provides good material technology support for the future pretreatment, purification and collection of veterinary drug residues.

[0027] (3) The detection technology for antibiotic residues enriched and separated using mZIF-8 was carried out by the quadrupole-linear ion trap liquid chromatography-mass spectrometry (LC-Q-LIT-6610 model) developed by the National Institute of Metrology of China. Compared with similar foreign models, this model of mass spectrometer has the same detection sensitivity and higher detection stability, providing technical support and theoretical basis for the rapid, accurate and low-cost pretreatment and integrated detection and quantification of veterinary drug residues in animal food. It has the technical benefits and application value of filling the domestic gap in multi-target detection of veterinary drug residues. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the process for preparing magnetic microparticle metal-organic framework materials according to the present invention.

[0029] Figure 2 Characterization diagrams of the magnetic microparticle metal-organic framework material (mZIF-8) prepared in Example 1 of this invention: (a) is a flowchart of the crystal growth process of mZIF-8; (b) is a SEM image of a rhombic hexahedral ZIF-8 crystal with (001) crystal facets; (c) is a truncated rhombic dodecahedral ZIF-8 crystal with (001) and (011) crystal facets; (d) is a rhombic dodecahedral ZIF-8 crystal with (011) crystal facets; (f) is a SEM-EDS elemental energy spectrum distribution of mZIF-8; (g) is an XRD pattern of mZIF-8; and (h) is an XPS pattern of mZIF-8.

[0030] Figure 3 Thermodynamic isothermal adsorption curves of various small molecule veterinary drug compounds were obtained using the magnetic microparticle metal-organic framework materials (mZIF-8) and mUiO-66 of this invention.

[0031] Figure 4 Optimize the preprocessing conditions for mZIF-8.

[0032] Figure 5 The extracted ion chromatograms / mass spectra of ciprofloxacin and norfloxacin obtained by LC-MS / MS method.

[0033] Figure 6 This is a schematic diagram of the preprocessing method based on the mZIF-8 of the present invention. Detailed Implementation

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0035] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0036] Example 1: Preparation and characterization of magnetic microparticle metal-organic framework materials

[0037] The preparation method flowchart is as follows Figure 1 As shown.

[0038] (1) Preparation of magnetic nanoparticles

[0039] Under a protective atmosphere, nitrogen gas was continuously purged into a three-hole flask (10 mL / min). Solid FeCl3·6H2O and solid FeCl2·4H2O were dissolved in 45 mL of deionized water, respectively. The FeCl3·6H2O and FeCl2·4H2O solutions were added intermittently at a rate of 5 mL / min. High-temperature co-precipitation crystallization was carried out at 90℃ for 4 hours, with 10 mL of NH3·H2O slowly added dropwise during the process. The total reaction volume was controlled to 100 mL by connecting a reflux tube, thus obtaining magnetic Fe3O4 nanoparticles.

[0040] (2) Preparation of magnetic microparticle metal-organic frameworks (mZIF-8)

[0041] After vacuum drying, 100 mg of magnetic nanoparticles were dispersed in 10 mL of deionized water, and 70 mmol (5.74 g) of 2-MI was added. The mixture was stirred for 10 min, and then 1.0 mmol of Zn(NO3)2·6H2O (0.297 g) was added and stirred for 1.0 h to obtain the initial product mZIF-8 (wherein, the molar ratio of 2-MI to Zn(NO3)2·6H2O was 70:1, and the mass ratio of 2-MI to magnetic nanoparticles was 1.4 g:10 mg).

[0042] (3) The product mZIF-8 was washed twice with anhydrous ethanol and then once with deionized water. After magnetic separation and collection, it was stored in deionized water at low temperature for later use.

[0043] The SEM-EDS image, X-ray crystal diffraction pattern, and X-ray photoelectron spectrum of the mZIF-8 material prepared in this embodiment are shown below. Figure 2 As shown, where, Figure 2 a is a schematic diagram of the synthesis process of mZIF-8, as shown below. Figure 2 As shown in b-2e, rhombic hexahedral ZIF-8 crystals with (001) crystal faces are first grown in an aqueous solution of magnetic nanoparticles. Figure 2 b), then a ZIF-8 crystal with a truncated rhombic dodecahedral crystal form having (001) and (011) crystal planes is formed. Figure 2 c), and then, using the (011) crystal face as the dominant growth plane, the most stable crystal configuration, a rhombic dodecahedral ZIF-8 crystal with the (011) crystal face, is grown. Figure 2 d) Finally, the magnetic nanoparticles ZIF-8 self-assemble in aqueous solution to form on the edges and centers of the crystal faces of ZIF-8 crystals. Figure 2 e). The surface of ZIF-8 (particle size approximately 400–500 nm) contains magnetic Fe3O4 nanoparticles with a particle size of 20–50 nm, and the overall particle size of mZIF-8 is approximately 450–550 nm; further EDS elemental distribution analysis was performed on the mZIF-8 in the SEM images, such as… Figure 2 As shown in f, it can be concluded that mZIF-8 is mainly composed of five elements: Zn (zinc), O (oxygen), C (carbon), N (nitrogen), and Fe (iron). Crystal X-ray diffraction analysis of the mZIF-8 magnetic microparticles, as shown... Figure 2 As shown in g, the crystal orientation of mZIF-8 remains consistent with that of the ZIF-8 prototype, with the most stable (011) crystal orientation being the dominant crystal plane; all mZIF-8 exhibits the characteristic crystal orientations of ZIF-8: (011), (002), (112), and (222). XPS elemental energy dispersive spectroscopy analysis of mZIF-8 revealed that, compared to ZIF-8, mZIF-8 mainly contains five elements: Zn2p (zinc), O1s (oxygen), C1s (carbon), N1s (nitrogen), and Fe2p (iron), and the elemental distribution results are consistent with those of SEM-EDS.

[0044] Example 2: Adsorption performance of magnetic microparticle metal-organic frameworks (mZIF-8) for various veterinary drug molecules

[0045] The adsorption performance of the synthesized mZIF-8 magnetic microparticles on fluoroquinolones (norfloxacin-NOR, ciprofloxacin-CIP, ofloxacin-OFL), tetracyclines (tetracycline-TC, oxytetracycline-OTC, and chlortetracycline-CTC) and chloramphenicol (CAP) was evaluated by isothermal adsorption tests (298 K).

[0046] (1) Weigh 20 mg of each antibacterial drug solid powder and dissolve them in 10 mL of a suitable solvent (NOR and OFL are dissolved in glacial acetic acid solution, and CIP, TC, OTC, CTC and CAP are dissolved in water) to prepare stock solutions with a concentration of 2 mg / mL; dilute the stock solutions to working solutions of 0.1, 0.5, 1.0, 5.0, 10, 20, 40, 60, 80, 100, 150 and 200 mg / L.

[0047] (2) Before adsorption, the mZIF-8 material was subjected to vacuum at 120℃ for 12 hours to remove guest molecules (activation). Then, the above three MOFs materials were added to the working solutions of each concentration, with a feed amount of 1.0 g / L.

[0048] (3) Shake adsorption for 48 h to ensure that the adsorption of all MOF materials reaches saturation; after adsorption is completed, centrifuge at 10000 rpm / min for 10 min, collect the supernatant, and quantify the remaining concentration of antibacterial drug by ultraviolet spectrophotometry.

[0049] (4) The data after adsorption were fitted and analyzed using the Langmuir model (Formula 1-1), Freundlich model (Formula 1-2), Temkin model (Formula 1-3) and DR model (Formula 1-4).

[0050] The saturated adsorption capacity of mZIF-8 for various veterinary antibiotics is as follows: Figure 3 The following drugs were listed: chloramphenicol (67.81 mg / g), tetracycline (69.69 mg / g), chlortetracycline (76.93 mg / g), oxytetracycline (40.67 mg / g), norfloxacin (76.50 mg / g), ofloxacin (50.95 mg / g), and ciprofloxacin (233.12 mg / g).

[0051] Example 3: Rapid magnetic separation, enrichment, and high-precision quantitative detection of quinolone drugs in milk using magnetic microparticle metal-organic frameworks (mZIF-8)

[0052] Mass spectrometry instrumentation methods and sample pretreatment:

[0053] (1) Optimization of preprocessing conditions

[0054] The dosage, adsorption time, solution pH, and salt ion concentration of adsorbent mZIF-8 in the pretreatment process were optimized to investigate the extraction effect of mZIF-8 on veterinary antibiotics and determine the required adsorbent dosage and adsorption time for pretreatment in actual samples.

[0055] Before use, the mZIF-8 material is activated in a vacuum at 120℃ for 12 hours.

[0056] mZIF-8 dosage optimization: Weigh 0.1, 0.2, 0.5, 1.0, 2.0, 5.0, and 10.0 mg of M-ZIF-8 and add them to 1.0 mL of 30 mg / L working solutions of ciprofloxacin, norfloxacin, and chloramphenicol, respectively. Shake and adsorb for 20 min. Magnetic separation is performed, and the supernatant is collected. The remaining drug concentration in the supernatant is measured, and the adsorption capacity of mZIF-8 is calculated. The optimal dosage of adsorbent in water and milk is determined to be 2.0 mg / g. Figure 4 b and Figure 4 e).

[0057] Optimization of mZIF-8 adsorption time: 2.0 mg of mZIF-8 was weighed and added to 1.0 mL of ciprofloxacin, norfloxacin, and chloramphenicol working solutions with a concentration of 10 mg / mL. Adsorption was performed with shaking for 10, 20, 30, 40, 50, and 60 min, respectively. The supernatant was magnetically separated, and the concentration of each drug remaining in the supernatant was tested. The optimal adsorption time was determined to be 20 min in water. Figure 4 a) The adsorption time in milk is 30 minutes, see Figure 4 f).

[0058] Solution pH optimization: Take 1.0 mL of 10 mg / mL working solutions of ciprofloxacin, norfloxacin, and chloramphenicol, and adjust the pH to 4, 5, 6, 7, 8, 9, and 10. Weigh 2.0 mg of mZIF-8 and add it to the working solutions at different pH values, then shake and adsorb for 20 min. Magnetic separation is performed to collect the supernatant, and the remaining drug in the supernatant is tested to determine the optimal pH of the solution as 7.0. Figure 4 c).

[0059] Optimization of solution salt ion concentration: Prepare 1.0 mL of 10 mg / L standard solutions of ciprofloxacin, norfloxacin, and chloramphenicol, respectively. Add appropriate amounts of NaCl to achieve salt concentrations of 0, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 mol / L, and stir to dissolve. Weigh 2.0 mg of mZIF-8 and add it to the working solutions with different NaCl concentrations, and allow to adsorb for 20 min by shaking. Magnetic separation is performed to collect the supernatant, and the concentration of remaining drug in the supernatant is tested. The results show that when the solution salt ion concentration is 0–0.5 mol / L, mZIF-8 has no significant effect on the adsorption of each drug. Figure 4 d).

[0060] (2) Sample pretreatment

[0061] Accurately weigh 1.0 g of homogenized animal tissue sample into a 50 mL centrifuge tube, add 3 mL of acetonitrile, then add 2.0 mg of mZIF-8 solid powder pretreatment adsorbent. Vortex for 2 min (10000 r / min), sonicate for 5 min, centrifuge for 5 min (4000 r / min), and repeat once. Combine the supernatants, defatted with 5 mL of n-hexane, mix well, and centrifuge. Collect the lower layer and concentrate to dryness under nitrogen. Redissolve in 1 mL of the initial mobile phase, add 1 mL of n-hexane, mix well, centrifuge, collect the lower layer, and filter through a 0.22 μm organic phase filter membrane for LC-MS / MS analysis.

[0062] (3)Liquid phase conditions

[0063] Instrument: Dalian Elite 3200; Column: Dalian Elite C18 column (4.6mm×150mm, 5μm); Mobile phase: A: 0.1% formic acid aqueous solution, B: 0.1% formic acid-acetonitrile; Flow rate: 0.6mL / min; Injection volume: 10μL.

[0064] Gradient elution conditions: see Table 1

[0065] Table 1 Gradient elution conditions

[0066]

[0067] (4) Mass spectrometry conditions

[0068] Instrument: Quadrupole-Linear Ion Trap Liquid Chromatography-Mass Spectrometry (LC-Q-LIT-6610 model) mass spectrometer independently developed by the National Institute of Metrology, China; Ion source: Electrospray ionization source; Scan mode: Positive ion scan; GAS SHEATH: 46.5; GASAUX: 23.5; GAS RES: 0.5; ESI-HV: 500; IGD-RFAMP: 400; EM1: -1150; EM2: -1150; APIC: 345; Ion source temperature: 280℃ (mass spectrometry parameters are shown in Table 2); Figure 5 As shown in a, the retention time (RT) of norfloxacin detected by mass spectrometry was 4.89 min, the quantitative ion was m / z 276.094, and the qualitative ion was m / z 302.063; Figure 5 As shown in b, the retention time (RT) of ciprofloxacin detected by mass spectrometry was 4.91 min, the quantitative ion was m / z 288.139, and the qualitative ion was m / z 314.102.

[0069] Table 2 Ion optical parameters and retention times of quinolone veterinary drugs

[0070]

[0071] A schematic diagram of the mZIF-8-based preprocessing technology is shown below. Figure 6 .

[0072] The limits of detection and quantitation for quinolones in milk using the LC-MS / MS method were 1–10 ppb and 2.5–20 ppb, respectively. Within the range of 10–450 ppb, the coefficient of determination R0 was [value missing]. 2 ≥0.9900, precision ≤9.46%, recovery rate 81.97%~118.49%.

[0073] (5) Comparison of adsorption performance of magnetic ZIF-8 (mZIF-8) and magnetic UiO-66 (mUiO-66)

[0074] Based on the mZIF-8 material and experimental methods described in Examples 1, 2, and 3, the adsorption performance of mZIF-8 and mUiO-66 for different veterinary antibiotics was tested. The maximum adsorption capacity of the two magnetic metal-organic framework nanocomposites for various antibiotics was determined using isothermal adsorption tests. The results are as follows: Figure 3 As shown in a-3c, it can be seen that the adsorption type of mZIF-8 for ciprofloxacin, norfloxacin, and chloramphenicol belongs to the Langmuir type adsorption curve (chemisorption); from Figure 3 As can be seen from d, the adsorption curves of mUiO-66 for the five sulfonamides also belong to the Langmuir adsorption curves of chemical adsorption.

[0075] Table 3 Summary of adsorption and elution systems of different veterinary antibiotics for magnetic MOF composite materials

[0076]

[0077]

Claims

1. Application of a magnetic microparticle metal-organic framework material in the detection of veterinary drug residues in animal-derived solid samples; The magnetic microparticle metal-organic framework material is used in the pretreatment of animal-derived solid samples to adsorb small molecule compounds of veterinary drugs. The veterinary drug small molecule compound is ciprofloxacin; The magnetic microparticle metal-organic framework material is a composite of ZIF-8 metal-organic framework material with (011) crystal plane and nano-magnetic particles. The magnetic microparticle metal-organic framework material has a particle size of 450~550 nm; The nanomagnetic particles are Fe3O4 magnetic nanoparticles; The preparation method of the magnetic microparticle metal-organic framework material includes the following steps: The nanomagnetic particles are dispersed in an aqueous solution of 2-methylimidazole and zinc nitrate and then self-assembled to obtain the nanomagnetic particles.

2. The application according to claim 1, characterized in that: The (011) crystal planes of the ZIF-8 metal-organic framework material form rhombic dodecahedrons with a particle size of 400~500 nm. The nanomagnetic particles have a particle size of 20~50 nm, and the nanomagnetic particles are uniformly distributed at the edges and center of the crystal faces of the rhombic dodecahedron of the ZIF-8 metal-organic framework material.

3. The application according to claim 1, characterized in that: The preparation method of the nanomagnetic particles includes the following steps: FeCl3·6H2O and FeCl2·4H2O were crystallized at high temperature in water under an inert atmosphere, and NH3·H2O was added. The high-temperature crystallization is carried out at a temperature of 80~100℃ for 3~5 hours.

4. The application according to claim 1, characterized in that: The molar ratio of 2-methylimidazole to zinc nitrate is 60-80:1; In the aqueous solution of the nanomagnetic particles, the concentration of the nanomagnetic particles is 5~25 mg / mL; The mass ratio of 2-methylimidazole to the magnetic nanoparticles is 1.4 g: 5~20 mg.

5. The application according to claim 1, characterized in that: The animal-derived solid samples are edible muscle tissue, dairy products, or egg products from animals.

6. A method for detecting veterinary drug residues in animal-derived solid samples, comprising the following steps: Animal-derived solid samples were pretreated, and then small molecule compounds of veterinary drugs were adsorbed using magnetic microparticle metal-organic framework materials. After magnetic separation and elution, LC-MS / MS detection was performed. The veterinary drug small molecule compound is ciprofloxacin; The magnetic microparticle metal-organic framework material is a composite of ZIF-8 metal-organic framework material with (011) crystal plane and nano-magnetic particles. The magnetic microparticle metal-organic framework material has a particle size of 450~550 nm; The nanomagnetic particles are Fe3O4 magnetic nanoparticles; The preparation method of the magnetic microparticle metal-organic framework material includes the following steps: The nanomagnetic particles are dispersed in an aqueous solution of 2-methylimidazole and zinc nitrate and then self-assembled to obtain the nanomagnetic particles.

7. The method according to claim 6, characterized in that: The (011) crystal planes of the ZIF-8 metal-organic framework material form rhombic dodecahedrons with a particle size of 400~500 nm. The nanomagnetic particles have a particle size of 20~50 nm, and the nanomagnetic particles are uniformly distributed at the edges and center of the crystal faces of the rhombic dodecahedron of the ZIF-8 metal-organic framework material.

8. The method according to claim 6 or 7, characterized in that: The animal-derived solid samples are edible muscle tissue, dairy products, or egg products from animals.

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