An oxfendazole molecularly imprinted material and a preparation method thereof

Abstract

The application discloses an oibendazol molecular imprinting material and a preparation method thereof. SiO2@C=C is used as a carrier, and oibendazol is used as a template molecule, so that the molecular imprinting material with specific adsorption effect on oibendazol is prepared. The molecular imprinting material has high stability and specific adsorption capacity, and especially for oibendazol, the molecular imprinting material still shows excellent specific adsorption effect even in a complex environment.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to an octendaazole molecularly imprinted material and its preparation method. Background Technology

[0002] Benzimidazole compounds, since their first synthesis in the 1960s, have been widely used in agriculture and animal husbandry worldwide due to their high efficiency and low cost. These compounds, such as carbendazim, albendazole, thiabendazole, obendazole, and flubendazole, play an important role in agriculture and animal husbandry as broad-spectrum fungicides and anthelmintics. However, improper or excessive use can lead to residues in animal products, which can then accumulate in the human body through the food chain, posing a threat to human health.

[0003] Currently, the main methods for detecting benzimidazole veterinary drug residues include HPLC and LC-MS, CE and CE-MS, immunoassay, and biosensor methods. In recent years, the main research targets for benzimidazole veterinary drug detection have been thibendazole, fenbendazole, albendazole, and their metabolites, with less research on oxadazole. During the detection process, the sample pretreatment method has a crucial impact on the accuracy of the target substance detection results. Solid-phase extraction (SPE) is currently a widely used pretreatment method. After SPE pretreatment of food samples, the detection of trace target substances may be interfered with by residual impurities in the matrix, thus reducing the sensitivity and accuracy of the analysis. For the detection of benzimidazole veterinary drugs in food, the SPE column packing materials currently used are mostly general adsorbents, unable to selectively adsorb specific target substances; the presence of analogues or impurities can significantly affect the quantitative analysis results. Furthermore, existing pretreatment methods also have shortcomings such as large matrix effects, poor extraction and purification effects, and low recovery rates. Therefore, developing a novel highly selective adsorption material is of great significance for the detection and regulation of ocbendazole in food. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide an octendaazole molecularly imprinted material and its preparation method, thereby solving the problems of large matrix interference, poor purification effect, and low recovery rate in the detection of octendaazole using existing technologies.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] An octendaazole molecularly imprinted material, comprising a carrier material and a template molecule, wherein the carrier material is a SiO2@C=C carrier material, and the template molecule is octendaazole; the template molecule is linked to the carrier material through a functional monomer and a crosslinking agent; the functional monomer is one of 4-vinylpyridine, methacrylic acid, or acrylamide.

[0007] Preferably, the crosslinking agent is one of ethylene glycol dimethacrylate, divinylbenzene, or trimethylolpropane trimethacrylate.

[0008] This invention also provides a method for preparing an octendaazole molecularly imprinted material, which specifically includes the following steps:

[0009] Step 1: Obtain nano-SiO2 particles and add them to an ethanol-water solution (the volume ratio of anhydrous ethanol to water in the ethanol-water solution is 4:1) for ultrasonic treatment to disperse them evenly. Then, nitrogen gas is introduced, and ammonia and 3-(methacryloyloxy)propyltrimethoxysilane are added sequentially. The reaction is carried out at 60-70℃ for 22-26 hours. After centrifugation, washing and drying of the reaction product, SiO2@C=C support material is obtained. The volume ratio of ammonia to 3-(methacryloyloxy)propyltrimethoxysilane is 3:4, and 1g of nano-SiO2 particles are added to every 100mL of ethanol-water solution.

[0010] Step 2: Dissolve the template molecule in a solvent, add the functional monomer, and stir at room temperature to prepolymerize and obtain a prepolymer solution; then, disperse the SiO2@C=C support material in the prepolymer solution, add the initiator and crosslinking agent, and continuously purge with nitrogen to remove oxygen; then, under sealed conditions, carry out the polymerization reaction at 55-65℃ for 6-24 hours to obtain a white suspension product; after centrifugation, wash the white product to elute the template molecule, and then dry it to obtain the octenadazole molecularly imprinted material OBZMIPs; wherein, the molar ratio of template molecule, functional monomer and crosslinking agent is 1:(0.25-4):(5-25); the mass of the initiator added is at least 1 times the mass of the template molecule.

[0011] Preferably, the functional monomer is one of 4-vinylpyridine, methacrylic acid, or acrylamide.

[0012] Preferably, the crosslinking agent is one of ethylene glycol dimethacrylate, divinylbenzene, or trimethylolpropane trimethacrylate.

[0013] Preferably, the initiator is one of azobisisobutyronitrile (AIBN) and azobisisoheptanenitrile (AIHH).

[0014] Preferably, in step 2, the solvent is one of tetrahydrofuran or dimethyl sulfoxide.

[0015] This invention discloses the application of an octenazole molecularly imprinted material, wherein the octenazole molecularly imprinted material or the octenazole molecularly imprinted material prepared by the above preparation method can selectively adsorb octenazole in the sample.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This invention discovers that by using surface molecular imprinting technology, with modified silica nanoparticles (SiO2@C=C) as a carrier, a functional monomer selected from 4-vinylpyridine, methacrylic acid, or acrylamide is linked to the template molecule and the carrier through a crosslinking agent. After the template molecule is eluted and removed, the obtained octendaazole molecularly imprinted material has high stability and specific adsorption capacity, especially for octendaazole, which exhibits high specificity. Even in complex environments, the octendaazole molecularly imprinted material still shows excellent selective adsorption performance.

[0018] 2. Existing technologies require template molecules with high solubility when preparing molecularly imprinted materials. However, octendaazole is very poorly soluble in water and most organic solvents. The method described in this invention, using octendaazole as the template molecule, can successfully prepare the corresponding molecularly imprinted template material. Moreover, this invention optimizes the preparation method of the molecularly imprinted material, further optimizing the types of functional monomers, cross-linking agents, and solvents, as well as the amounts of template molecules, functional monomers, and cross-linking agents, thereby further improving the adsorption effect of the molecularly imprinted material. At the same time, the adsorption conditions are also optimized, enabling the molecularly imprinted material to achieve the optimal adsorption effect in the optimized pH environment, thereby achieving the maximum selective adsorption of octendaazole and thus realizing the purpose of accurately extracting octendaazole from complex food matrices. Attached Figure Description

[0019] Figure 1 Here are scanning electron microscope (SEM) images; among them, Figure 1 A is a scanning electron microscope image of OBZMIP7. Figure 1 B is a scanning electron microscope image of NIP7.

[0020] Figure 2 The infrared spectrum is shown below; where (1) is SiO2; (2) is SiO2@C=C; (3) is OBZMIP7; and (4) is NIP7.

[0021] Figure 3 The adsorption amount and imprinting factor of the olbendazole molecularly imprinted material for the target molecule under different conditions; wherein, Figure 3 A represents different solvent ratios; Figure 3 B represents different pH values. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0023] Unless otherwise specified in the specific circumstances, the numerical ranges listed herein include upper and lower limits, as well as all integers and fractions within that range, but are not limited to the specific values ​​listed when the range is defined.

[0024] I. An Olbendazole Molecular Imprinted Material

[0025] The octendaazole molecularly imprinted material of the present invention comprises a carrier material and a template molecule, wherein the carrier material is a SiO2@C=C carrier material and the template molecule is octendaazole; the template molecule is linked to the carrier material through a functional monomer and a crosslinking agent; the functional monomer is one of 4-vinylpyridine, methacrylic acid or acrylamide.

[0026] Molecular imprinting technology can precisely create "molecular pockets" based on the structure of target molecules, thereby achieving highly specific recognition and adsorption and reducing competitive adsorption by non-target molecules. However, although the principle of molecular imprinting technology is simple, the actual operation involves complex steps such as template molecule selection, functional monomer design, and determination of optimal conditions. Furthermore, it is easily affected by interference from substances with similar structures to the target molecule, thus reducing the specific recognition ability of the imprinted material. In this invention, ordinary nano-SiO2 material is used as a carrier and further modified. Through exploration and comparative experiments on parameters such as the type of functional monomer, the type of porogen, the material ratio, polymerization temperature, and polymerization time, the optimal technical route for successfully preparing the molecular imprinted material was finally optimized. Performance studies of the prepared molecular imprinted material revealed that the material prepared under optimal conditions exhibits excellent specific adsorption of octendaazole. In particular, the adsorption capacity of the molecular imprinted material for octendaazole is significantly higher than that for other similar substances under various benzimidazole drug interference conditions.

[0027] In some embodiments, the present invention has investigated the types of functional monomers, using 4-vinylpyridine (4-VP), methacrylic acid, or acrylamide as the functional monomer. This enables the obtained octenadazole molecularly imprinted material to exhibit excellent adsorption performance for octenadazole. The specific adsorption performance of the molecularly imprinted material prepared with these three functional monomers is significantly better than that of other functional monomers. However, there are certain differences in the adsorption performance among these three functional monomers. Further research revealed that when 4-VP is used as the template molecule, it exhibits a significantly better imprinting effect than MAA and AM. However, this does not mean that the other two functional monomers cannot achieve the adsorption performance described in this invention. Therefore, the functional monomer is further preferably 4-vinylpyridine.

[0028] In some embodiments, the crosslinking agent is one of ethylene glycol dimethacrylate, divinylbenzene, or trimethylolpropane trimethacrylate. One end of the functional monomer first forms a non-covalent bond with the template molecule, while the other end reacts with the crosslinking agent to form a covalent bond. The other end of the crosslinking agent is covalently connected to the carrier material, achieving the purpose of encapsulating an imprinted layer on the surface of the carrier material. The template molecules are then eluted to remove the imprint, ultimately obtaining a surface molecularly imprinted material capable of selectively adsorbing octendaazole.

[0029] II. A method for preparing octendaazole molecularly imprinted materials

[0030] Step 1: Obtain nano-SiO2 particles and add them to an ethanol-water solution for ultrasonic treatment to disperse them evenly. Then, nitrogen gas is introduced, and ammonia (mass fraction of 25%–30%) and 3-(methacryloyloxy)propyltrimethoxysilane are added sequentially. The reaction is carried out at 60–70 °C for 22–26 h. After centrifugation, washing, and drying, SiO2@C=C support material is obtained. The volume ratio of ammonia to 3-(methacryloyloxy)propyltrimethoxysilane is 3:4, and 1 g of nano-SiO2 particles are added to every 100 mL of ethanol-water solution.

[0031] Step 2: Dissolve the template molecule in a solvent, add the functional monomer, and stir at room temperature to prepolymerize and obtain a prepolymer solution; then, disperse the SiO2@C=C carrier material in the prepolymer solution, add the initiator and crosslinking agent, and continuously purge nitrogen to remove oxygen; then, under sealed conditions, carry out the polymerization reaction at 55-65℃ for 6-24 hours to obtain a white suspension product; wash the white suspension product to elute the template molecule, and then dry it to obtain the octenadazole molecularly imprinted material OBZMIPs; wherein, the molar ratio of template molecule, functional monomer and crosslinking agent is 1:(0.25-4):(5-25); the mass of the initiator added is at least 1 times the mass of the template molecule.

[0032] In some embodiments, the molar ratio of template molecule, functional monomer, and crosslinking agent is 1:(0.25–4):(5–25), and controlling this range ensures successful preparation of the oxendazole molecularly imprinted material. Therefore, the molar ratios of template molecule, functional monomer, and crosslinking agent are 1:0.25:5, 1:0.5:10, 1:1:20, 1:2:10, 1:2:15, 1:2:25, 1:2:20, 1:3:20, 1:4:20, etc., as well as all ranges and subranges between these values. It should be understood that, in embodiments, any of the above ranges can be combined with any other range.

[0033] In some embodiments, the initiator is added at least once the mass of the template molecule to ensure an excess of initiator. Therefore, the amount of initiator added can be more than once, twice, three times, or more the mass of the template molecule, as well as all ranges and subranges between these values. It should be understood that, in embodiments, any of the above ranges can be combined with any other range.

[0034] III. Application of an Olbendazole Molecular Imprinted Material

[0035] The octendaazole molecularly imprinted material described above, or the octendaazole molecularly imprinted material prepared by the above method, can selectively adsorb octendaazole. Specifically, the octendaazole molecularly imprinted material can directly adsorb octendaazole in solution, making it suitable for the efficient enrichment of octendaazole residues in complex food matrices.

[0036] IV. Examples and Comparative Examples

[0037] Example 1:

[0038] Step 1: Silica synthesis and KH570 modification

[0039] Using traditional The method first prepares nano-SiO2 particles. The specific steps are as follows: 114 mL of anhydrous ethanol was measured into a 250 mL round-bottom flask, and 11.4 mL of tetraethoxysilane (TEOS) was added (denoted as solution A). 50 mL of anhydrous ethanol and 76.5 mL of water were measured into another round-bottom flask, and 7.6 mL of ammonia water was added (denoted as solution B). Solutions A and B were rapidly mixed, and then magnetically stirred at room temperature for 6 hours. After the reaction, a milky white SiO2 colloidal nanoparticle dispersion was obtained. This dispersion was centrifuged at 8000 rpm for 10 minutes, and the supernatant was discarded. The centrifuged product was redispersed in anhydrous ethanol, and repeatedly circulated and washed until the supernatant was neutral. The product was then dried in a 50 °C oven for 24 hours to obtain nano-SiO2 particles.

[0040] Weigh 1g of nano-SiO2 particles and add them to a three-necked flask containing 20mL of pure water and 80mL of anhydrous ethanol. Sonicate for 30min to ensure uniform SiO2 dispersion. Purge with nitrogen gas, and while stirring rapidly, add 3mL of ammonia and 4mL of 3-(methacryloyloxy)propyltrimethoxysilane (MPS). React in a 65℃ oil bath for 24h. Centrifuge the resulting white product at 8000rpm for 5min, discard the supernatant, and repeatedly wash until the supernatant is neutral. Then, dry the product in a 50℃ oven for 24h to obtain the SiO2@C=C support material.

[0041] Step 2: Synthesis of OBZMIP

[0042] 10.0 mg (0.04 mmol) of the template molecule obendazole was weighed and placed in a 50 mL round-bottom flask. 20 mL of solvent was added, and the mixture was sonicated until completely dissolved. Functional monomers were added in different proportions (detailed conditions are shown in Table 1). The mixture was then magnetically stirred at room temperature for 30 min for prepolymerization. Next, 50 mg of SiO2@C=C was completely dispersed in the above solution, and appropriate amounts of ethylene glycol dimethacrylate (EGDMA) crosslinking agent and 20 mg of azobisisobutyronitrile (AIBN) initiator were added. N2 was continuously purged for deoxygenation (15 min). After deoxygenation, the round-bottom flask was sealed, and the mixture was magnetically stirred in a 60 °C oil bath to carry out the polymerization reaction, yielding a white suspension product. The product was washed with a methanol:glacial acetic acid (v / v, 9:1) mixture until the supernatant showed no UV absorption at 294 nm. Finally, the material was washed with methanol until neutral and dried in a 50 °C oven for 12 h. The obtained product was OBZMIPs.

[0043] As a comparative example, non-imprinted polymers (NIPs) were prepared following the same steps as described above, except that no template molecules were added, as shown in Table 1.

[0044] Table 1. Adsorption capacity and selectivity of OBZMIPs prepared under different conditions (n=3)

[0045]

[0046] The results are shown in Table 1. It can be seen that 4-vinylpyridine (4-VP) exhibits significantly better imprinting effects than methacrylic acid (MAA) and acrylamide (AM) when used as the functional monomer. Therefore, 4-VP was chosen as the functional monomer for subsequent synthesis experiments. With increasing ratios of functional monomer and crosslinking agent, both adsorption capacity and imprinting factor initially increased and then significantly decreased. This is because excess template molecules and crosslinking agents result in a compact polymer structure, forming more non-specific surface-coated imprinting cavities. Analyzing both adsorption capacity and imprinting factor, the optimal preparation conditions were determined to be a template molecule:functional monomer:crosslinking agent ratio of 1:2:20. Furthermore, since OBZ is only slightly soluble in tetrahydrofuran and dimethyl sulfoxide, the effects of tetrahydrofuran and dimethyl sulfoxide as porogens were compared. It was found that the adsorption capacity and imprinting factor of dimethyl sulfoxide as a porogen were slightly lower than those of tetrahydrofuran. Therefore, tetrahydrofuran was used as the solvent for synthesizing OBZMIP. Finally, as the polymerization time increased, both the adsorption amount and the imprinting factor showed a gradual increasing trend. However, excessively long polymerization time would lead to an increase in non-specific adsorption sites. Therefore, 24h was chosen as the polymerization time for OBZMIP.

[0047] V. Performance Comparison

[0048] 1. Material Characterization

[0049] Taking Example 7 (OBZMIP7) and its corresponding non-imprinted polymer NIP7 in Table 1 as examples, the surface morphology of the carrier material, OBZMIP7, and NIP7 was observed using a scanning electron microscope (SEM, Zeiss Sigma 500, Germany). The functional groups on the material surface were analyzed using Fourier transform infrared spectroscopy (FTIR, Bruker Tensor 27, Germany), with the scanning wavelength range set to 400–4000 cm⁻¹. -1 Experiments were conducted at 77.3 K using a surface analyzer (Quadrasorb 2MP, US) to compare and study the structural and pore characteristics of OBZMIP and NIP. The specific surface area was calculated using the Brunauer-Emmett-Teller (BET) method, and the volume and diameter of the mesopores were calculated using the Barret-Joyner-Halender (BJH) method.

[0050] The surface morphology of OBZMIP and NIP was characterized using scanning electron microscopy. Figure 1 ).like Figure 1As shown, the particle size range of OBZMIP and NIP is approximately 100 nm to 200 nm, but the particle size and shape of OBZMIP are relatively uniform, while the particles of NIP are mostly aggregated small microspheres. Furthermore, both materials exhibit rough surface characteristics, but due to the imprinted cavities after the removal of the target molecules, the surface roughness of OBZMIP is greater than that of NIP. The microstructures of the other examples in Table 1 are similar to those of Example 7, while the microstructures of other non-imprinted polymer NIPs are similar to those of NIP7.

[0051] Infrared spectrum as shown Figure 2 As shown, the peaks in the spectrum were assigned using an attribution analysis, and the results are as follows: 3500 cm⁻¹ -1 ~3300cm -1 The broad peak in the band is caused by the OH stretching vibration of the material surface, 2957 cm⁻¹. -1 The peak at this location is related to the CH stretching vibration. In SiO2@C=C materials, it is located at 1709 cm⁻¹. -1 and 1634cm -1 The peaks can be attributed to C=O and C=C, respectively. Due to the presence of the C=C-COOR structure in KH570, the C=O absorption shifts to a lower wavenumber direction due to conjugation with C=C, indicating that the SiO2 surface has been successfully modified with a double bond structure. However, in OBZMIP and NIP, the conjugated structure is destroyed by the polymerization reaction, leaving only the R-COOR structure on the material surface; therefore, the C=O absorption peak appears at 1734 cm⁻¹. -1 At this location, the C=C absorption peak disappears. Furthermore, at 1100 cm⁻¹... -1 The strong absorption peak at 800 cm⁻¹ is caused by the antisymmetric stretching vibration of Si-O-Si. -1 and 470cm -1 The absorption peaks at 951 cm⁻¹ represent the symmetric stretching and bending vibrations of the Si-O bond, respectively. -1 The absorption peaks that appear on the left and right sides can be attributed to Si-H bond vibrations.

[0052] 2. Adsorption performance

[0053] The optimal solvent ratio and pH for OBZMIP adsorption of target molecules were investigated, followed by selective adsorption and recycling experiments.

[0054] Except for selectivity experiments and solid-phase extraction experiments, the concentration of oxendazole in the supernatant was measured using a high-performance liquid chromatograph (Agilent 1260, USA) equipped with a DAD detector. The chromatographic column was an InertSustain C1000. 18(4.6 × 250 mm, 5 μm). The mobile phase was 0.1% formic acid water (A) and methanol (B), with gradient elution set as follows: 0–2 min, 30%–60% B; 2–6 min, 60% B; 6–7 min, 60%–98% B; 7–8 min, 98% B; 8–8.5 min, 98%–30% B. The flow rate was 1.0 mL / min. The column temperature was 20 °C, the detection wavelength was 294 nm, and the injection volume was 20 μL. The sample concentrations for selectivity and SPE experiments were determined using UHPLC-TQMS.

[0055] (1) Adsorption solvent and pH investigation experiment

[0056] The experimental procedure for investigating the adsorption solvent and pH is as follows:

[0057] Add 3.0 mg of OBZMIP7 / NIP7 to 3 mL of a methanol:water (v / v, 4:6) solution containing 5 μg / mL of the target molecule OBZ. Place the centrifuge tube at 25°C and shake at 120 rpm for 2 h. After the reaction is complete, centrifuge at 10000 rpm for 5 min, and filter the supernatant through a 0.22 μm microporous membrane.

[0058] In the solvent investigation experiment, the ratio (v / v) of methanol to water was set to 2:8 to 6:4.

[0059] In the pH investigation experiment, the pH of the solution was adjusted to 1–9 using 0.1M hydrochloric acid and sodium hydroxide, respectively.

[0060] Figure 3 The effect of adsorption solvent and pH on the adsorption performance of OBZMIP is shown in the figure. Figure 3 As shown in Figure A, the adsorption capacities of OBZMIP and NIP gradually increase with the increase of the water content in the solvent, mainly due to non-specific hydrophobic interactions. The solvent composition of MeOH / H₂O (v / v, 4:6) exhibits the largest imprinting factor, meaning that OBZMIP demonstrates the highest selectivity under these solvent conditions. The pH of the reaction system is a key factor affecting the formation of hydrogen bonds between obendazole and the functional monomer, and also a key factor influencing the adsorption performance of OBZMIP. According to... Figure 3As shown in Figure B, the adsorption capacity and imprinting factor of OBZMIP gradually increase with increasing pH, reaching an optimal value at pH 5, and then showing a decreasing trend. At lower pH values, the strongly acidic environment hinders the formation of intermolecular hydrogen bonds, resulting in lower adsorption capacity, and the adsorption capacities of OBZMIP and NIP are essentially the same. At pH 5, OBZ is in a non-ionized state, while 4-VP may be partially protonated at this pH, carrying a positive charge. Therefore, strong hydrogen bonding and electrostatic interactions exist simultaneously between OBZ and 4-VP, exhibiting higher adsorption capacity and the highest imprinting factor, demonstrating optimal specific adsorption performance. Under these conditions, the adsorption capacity of OBZMIP is 295 μg / g, and the IF is 1.59.

[0061] (2) Selective adsorption experiment

[0062] Six benzimidazole compounds with structures similar to the template molecule OBZ were selected for competitive adsorption to investigate the specificity of OBZMIP. The experimental procedure is as follows:

[0063] Add 1 mL of mixed solution (5 μg / mL for each compound) to 5.0 mg of OBZMIP, shake at 120 rpm for 30 min at 20 °C, centrifuge at 8000 rpm for 5 min, take the supernatant and filter it through a 0.22 μm filter membrane, and detect it by LC-MS.

[0064] To evaluate the selectivity of OBZMIP7, competitive binding experiments were conducted on six benzimidazole veterinary drugs (or their metabolites) with structures similar to obendazole. The results are shown in Table 2. In a mixed system containing seven compounds, OBZMIP7 exhibited the highest adsorption capacity for the template molecule OBZ (36.18 μg / g), while the adsorption capacities for the other six compounds ranged from 0 to 11.13 μg / g. This is mainly because the imprinted cavity of OBZMIP and the template molecule OBZ have the most complementary affinity in terms of functional groups and stereochemistry, thus exhibiting the strongest competitive binding ability. Under calculable conditions, the selectivity factor ranged from 3.3 to 16.9, indicating that OBZMIP7 has high specificity for the template molecule OBZ. Therefore, even in complex environments, OBZMIP7 still exhibits excellent specific adsorption performance.

[0065] Table 2. Adsorption capacity and selectivity of OBZMIP for different compounds in mixed systems.

[0066] Olbendazole 36.18 - Thiabendazole 11.13 3.3 2-Aminofluorobenzamide 6.91 5.2 5-Hydroxythiabendazole 5.84 6.2 Dimetridazole (Dimetridazole) 2.14 16.9 Albendazole-2-aminosulfone 0 - aminomepiride 0 -

[0067] (3) Experiment on recycling

[0068] The reusability of adsorbents is a key factor in practical applications. The regenerability of OBZMIP7 was investigated through adsorption-desorption cycling. During five cycles, the adsorption capacity of OBZMIP7 did not show significant changes, with a relative standard deviation (RSD) of 4.41%. This indicates that the prepared OBZMIP7 possesses excellent recyclability and stability, and can be reused at least five times.

[0069] 3. Practical Application

[0070] To further evaluate the applicability of OBZMIP for extracting OBZ from food samples, this invention conducted spiked recovery tests on four meat samples—pork, pork skin, pork liver, and pork kidney—according to the limits specified in standard GB31650-2019. The OBZ recoveries in the four meat samples are listed in Table 3. Under conditions containing different concentrations of OBZ in the samples, the OBZ recoveries ranged from 68.37% to 100.19%, with RSDs ranging from 0.22% to 7.08%. This indicates that OBZMIP has strong applicability in the pretreatment of meat samples and demonstrates good practicality for the extraction of obendazole from actual samples.

[0071] Table 3. Parameters of the OBZMIP-SPE method for selective OBZ extraction.

[0072]

[0073] In a mixed system containing six analogs, OBZMIP7 still exhibits high selectivity for ocbendazole, with selectivity factors ranging from 3.3 to 16.9 for the six analogs. Furthermore, the prepared OBZMIP7 can be used to enrich ocbendazole from meat samples with high recoveries, meeting the requirements of standard GB31650-2019.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. An octendaazole molecularly imprinted material, characterized in that, The method for preparing the octendaazole molecularly imprinted material includes: Step 1: Obtain nano-SiO2 particles and add them to an ethanol-water solution for ultrasonic treatment to disperse them evenly. Then, nitrogen gas is introduced, followed by the sequential addition of ammonia and 3-(methacryloyloxy)propyltrimethoxysilane. The reaction is carried out at 60-70 °C for 22-26 h. After centrifugation, washing, and drying, the SiO2@C=C support material is obtained. The volume ratio of ammonia to 3-(methacryloyloxy)propyltrimethoxysilane is 3:4, and 1 g of nano-SiO2 particles is added to every 100 mL of ethanol-water solution. Step 2: The template molecule is dissolved in a solvent, a functional monomer is added, and prepolymerization is carried out by stirring at room temperature to obtain a prepolymerization solution; then, the SiO2@C=C support material is dispersed in the prepolymerization solution, an initiator and a crosslinking agent are added, and nitrogen gas is continuously purged to remove oxygen; then, under sealed conditions, the polymerization reaction is carried out at 55~65 °C for 24 h to obtain a white product; after centrifugation, the white product is washed to elute the template molecule, and then dried to obtain the octendaazole molecularly imprinted material OBZMIPs; Wherein, the template molecule is ocendazole; the functional monomer is 4-vinylpyridine; the crosslinking agent is ethylene glycol dimethacrylate; the mass of the initiator added is more than 1 times the mass of the template molecule; the solvent is tetrahydrofuran or dimethyl sulfoxide; when the solvent is tetrahydrofuran, the molar ratio of the template molecule, functional monomer and crosslinking agent is 1:1:20 or 1:2:20; when the solvent is dimethyl sulfoxide, the molar ratio of the template molecule, functional monomer and crosslinking agent is 1:2:

20.

2. The olbendazole molecularly imprinted material according to claim 1, characterized in that, The initiator is either azobisisobutyronitrile or azobisisoheptanenitrile.

3. An application of an octendaazole molecularly imprinted material, characterized in that, The octendaazole molecularly imprinted material according to claim 1 or 2 is used for selective adsorption of octendaazole.

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