Preparation and application of a new magnetic environmentally friendly molecularly imprinted material with high efficiency in adsorption and photodegradation of organophosphorus pesticides

Abstract

This invention discloses the preparation and application of a novel magnetic, environmentally friendly molecularly imprinted material (MIM) with high-efficiency adsorption and photodegradation for organophosphorus pesticides. The MIM comprises a magnetic ferroferric oxide core coated with mesoporous titanium dioxide to form a shell with photoinduced degradation properties. The MIM is further modified with double bonds and polymerized on the surface using methacrylic acid as a functional monomer and dichlorvos and chlorpyrifos as dual template molecules under the action of trimethylolpropane trimethacrylate (TRIM) crosslinker, forming a novel "core-shell" magnetic MIM. The resulting MIM exhibits uniform particle size, excellent dispersibility, broad-spectrum adsorption for organophosphorus pesticides, good resistance to extreme environments, and multiple reusability. The MIM can be used for the rapid enrichment and detection of organophosphorus pesticides, while minimizing the impact of matrix effects on detection. The MIM has high detection speed, covers a wide range of pesticides, and enables high-throughput detection.

Description

Technical Field

[0001] The present invention relates to a novel magnetic environmentally friendly adsorption imprinted material and its preparation method and application. The magnetic material is suitable for the adsorption and degradation of organophosphorus pesticides and can achieve the purpose of specific enrichment and rapid separation of organophosphorus pesticides in complex food samples, belonging to the field of analytical chemistry. Background Art

[0002] Studies have shown that excessive intake of organophosphorus pesticides increases the risk of aplastic anemia, damages the central nervous system and internal organs, and may even cause malformations, cancer, and mutations. In agriculture, although annual usage of the six most commonly used organophosphorus pesticides (trichlorfon, oxydemeton-methyl, phoxim, acephate, chlorpyrifos, and dichlorvos) has declined over the past decade, annual usage remains above 2,000 tons. This demonstrates that the problem of pesticide residues remains severe.

[0003] With the diversification of social life and the growing population, the demand for different types of food is increasing. This diverse food matrix has a significant impact on pesticide detection and is the main reason for the low sensitivity and accuracy of instrument detection. To ensure detection accuracy and sensitivity, sample pretreatment is essential. Currently, sample pretreatment commonly used for instrumentation to detect organic pollutants involves tedious steps such as extraction, centrifugation, column adsorption, elution, nitrogen purging or rotary evaporation, and volume adjustment. According to an analysis of sources of error in sample analysis published in the journal LC-GC, sample pretreatment time accounts for 60%-70% of the entire analytical process, significantly reducing detection efficiency. Therefore, current pretreatment methods, which are time-consuming, non-selective, and unable to be performed on-site, are hindering the development of rapid on-site testing. Achieving convenient, efficient, and selective enrichment and cleanup of samples is a primary challenge for rapid food testing, but the rapid testing industry has not paid sufficient attention to this issue. Therefore, the development of pretreatment materials for rapid extraction and separation with superior specificity, purification capabilities, and adsorption properties is a prerequisite for the implementation of rapid testing.

[0004] In recent years, molecularly imprinted materials (MIMs) have attracted attention due to their simple processing methods and efficient enrichment effects. MIMs are prepared by chemical means and a "hole" is constructed in the material that matches the target in terms of spatial structure or binding site, simulating the highly specific recognition modes of "antigen-antibody" and "substrate-enzyme". These materials have excellent physical stability and overcome the stringent environmental requirements of biomaterials. In addition, the material has advantages such as simple preparation process, good universal application, and controllable cost, making it widely popular in the fields of separation and purification, sensors, artificial antibodies, drug delivery, catalytic degradation, etc. However, most MIMs are currently packed in solid-phase extraction columns, which require activation, sample liquid passing through the column, and elution. Complex food samples can easily cause column blockage, resulting in prolonged pretreatment time. Dispersed solid-phase extraction materials avoid the "column plugging" problem, but are difficult to separate from the matrix and are difficult to use for rapid on-site pretreatment. The organophosphorus pesticide molecularly imprinted polymer prepared by Chen et al. (2017, https: / / doi.org / 10.1007 / s12161-017-0875-5) had an adsorption capacity of 23 mg / g for trichlorfon and 7 mg / g for dichlorvos. The molecularly imprinted polymer prepared by Li et al. (2022, https: / / doi.org / 10.1016 / j.jchromb.2021.123081) had an adsorption capacity of 81.37 mg / g for fenthion. The molecularly imprinted polymer prepared by Boulanouar et al. (2017, https: / / doi.org / 10.1016 / j.chroma.2017.07.067) had a low adsorption capacity of only 1 mg / g for malathion. Summary of the Invention

[0005] The present invention aims to provide a magnetic molecularly imprinted material that enriches and degrades organophosphorus pesticides, as well as its preparation method and application. This approach overcomes the shortcomings of conventional organophosphorus pesticide detection methods, such as high cost, time consumption, and complex procedures. Furthermore, the material exhibits significant degradation effects on organophosphorus pesticides, thereby overcoming the secondary environmental pollution associated with conventional molecularly imprinted methods.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] This invention incorporates nano-ferrosoferric oxide as the core of the material. The outer layer undergoes polymerization to form an imprinted shell with broad-spectrum recognition for organophosphorus pesticides, resulting in a molecularly imprinted material with a rapid magnetic response and a "core-shell" structure. This allows for the collection of imprinted polymers through an external magnetic field, significantly simplifying the processing of complex food matrices. Furthermore, the invention innovatively incorporates a "photoinducible" material into the imprinted shell, enabling the molecularly imprinted material to degrade residual pesticides after use through simple light treatment, achieving green regeneration. This eliminates the need for organic elution reagents and mitigates secondary contamination, resulting in an environmentally friendly pretreatment method with a broad substrate adsorption spectrum.

[0008] A magnetic molecular imprinted material for organophosphorus pesticides, comprising a core of magnetic ferrosoferric oxide and a surface-coated mesoporous titanium dioxide shell with "light-induced" degradation properties. The shell is further modified with double bonds, uses methacrylic acid as a functional monomer, and uses dichlorvos and chlorpyrifos as dual template molecules. Surface polymerization is performed under the action of a TRIM crosslinker to form a novel magnetic molecular imprinted polymer with a "core-shell" structure.

[0009] The particle size of the magnetic molecular imprinting material is 200-300 nm and has good magnetic characteristics.

[0010] The ratio of the magnetic molecular imprinting material template molecule: the functional monomer: the cross-linking agent is in the range of 1:1:1 to 1:10:20.

[0011] A method for preparing a magnetic molecular imprinted material for organophosphorus pesticides comprises the following steps:

[0012] S1: Hexahydrate ferric chloride and anhydrous sodium acetate are mixed in a certain proportion, a mixed solution of ethylene glycol and diethylene glycol is heated and fully stirred as a solvent, and then reacted in a high temperature and high pressure reactor under certain temperature conditions for a period of time. After the reaction is completed, the mixture is washed several times with anhydrous ethanol and then placed in a vacuum drying oven to obtain magnetic ferrosoferric oxide microspheres for standby use;

[0013] S2: Add a certain amount of ammonia water and tetrabutyl titanate to the material obtained in step S1, mechanically stir at 30-50°C, react under nitrogen protection for one day, adsorb with a magnet, wash several times with anhydrous ethanol, and then add a mixed solution of ethanol and water in a specific volume ratio. Place the mixture in a high-temperature and high-pressure reactor to react at a set temperature of 120-170°C for 5-10 hours. After the reaction is completed, wash and vacuum dry to obtain Fe3O4@mTiO2 mesoporous titanium dioxide coated magnetic beads.

[0014] S3: The material obtained in step S2 is dissolved in toluene, and then methoxysilane and triethylamine in a certain molar ratio are added, and mechanical stirring is carried out at a temperature of 60-90° C. for 2-5 hours, and the mixture is adsorbed with a magnet, washed, and vacuum dried;

[0015] S4: Add dichlorvos and chlorpyrifos, methacrylic acid, and trimethylolpropane trimethacrylate to the material obtained in step S3 at a molar ratio of 1:2:2 to 1:4:10, then add 100 to 300 mg of azobisisobutyronitrile in acetonitrile as the solvent, mechanically stir at 4 to 60° C. for 5 to 30 hours, adsorb with a magnet, and wash with anhydrous ethanol to remove the organophosphorus pesticide template molecules in the material. The washing is completed when dichlorvos and chlorpyrifos are no longer detected in the final washing solution.

[0016] S5: The particle size of the obtained organophosphorus pesticide molecular imprint was measured using scanning electron microscopy and transmission electron microscopy, and the particle size was in the range of 200 to 300 nm.

[0017] The magnetic molecular imprint of organophosphorus pesticides was added to 1 mmol / L dichlorvos, chlorpyrifos and phoxim solutions in a solvent of methanol:water = 5:5 (v / v) for 15 min and separated by magnetic properties.

[0018] Furthermore, after preparing the corresponding standard curve solution, the supernatant after magnetic separation was collected and analyzed using an ultraviolet spectrophotometer.

[0019] The preparation method, more specifically, comprises the following steps:

[0020] Step 1: dissolving 1 to 3 g of anhydrous sodium acetate and ferric chloride hexahydrate and 6 to 8 g of polyethylene glycol in a mixed solution of ethylene glycol and diethylene glycol in a volume ratio of 1:5 to 1:20 in a molar ratio of 1:1:10 to 1:10:100, transferring the mixed solution to a high-temperature and high-pressure reactor to continue the reaction at a temperature of 150 to 250° C. for 5 to 15 hours; after the reaction is completed, magnetic ferrosoferric oxide nanospheres are obtained;

[0021] Step 2: Dissolve 50-200 mg of ferroferric oxide microspheres in 80-130 mL of anhydrous ethanol and mechanically stir at 30-50°C, add 0.5-2 mL of ammonia water, and at the same time slowly drip 0.5-2 mL of tetrabutyl titanate dissolved in anhydrous ethanol, and react for 20-30 hours under nitrogen protection; after the reaction is completed, rinse the reactant with anhydrous ethanol, redissolve it in a mixed solution of ethanol and water, transfer it to a high-temperature and high-pressure reactor, set the temperature to 120-170°C, and the reaction time is 5-10 hours; after the reaction is completed, Fe3O4@mTiO2 mesoporous titanium dioxide coated magnetic bead material is obtained;

[0022] Step 3: Dissolve 100-200mg of Fe3O4@mTiO2 in toluene and mechanically stir at 60-90°C. Simultaneously, slowly add 50-200µL of methoxysilane and triethylamine dissolved in toluene to the reaction mixture. Allow the reaction to proceed for 2-5 hours under nitrogen. After the reaction is complete, rinse the mixture with anhydrous ethanol and dry it in a vacuum oven until ready for use. This yields Fe3O4@mTiO2@MPS.

[0023] Step 4: Dissolve the organophosphorus pesticides dichlorvos, chlorpyrifos, and methacrylic acid in acetonitrile at a ratio of 1:1:1 to 1:10:10. After prepolymerization in a refrigerator at 4°C for 10 to 20 hours, add 100 to 300 mg of Fe₃O₄@mTiO₂@MPS and react at 20 to 40°C for 1 to 2 hours. Then, add 7 to 15 mmol of trimethylolpropane trimethacrylate and 100 to 300 mg of azobisisobutyronitrile and react at 40 to 60°C for 5 to 10 hours. Finally, maintain the reaction at 50 to 70°C for 24 hours before terminating the reaction. The material is then washed with methanol:acetic acid (9:1 v / v) until the organophosphorus pesticide template molecules are no longer detected. Vacuum drying yields the organophosphorus pesticide magnetic molecularly imprinted material.

[0024] The synthesized magnetic imprinted material has a uniform particle size, excellent dispersibility, broad-spectrum adsorption for organophosphorus pesticides, good resistance to extreme environments, and multiple reusability. It can efficiently degrade a variety of highly toxic organophosphorus pesticides with long half-lives under light induction, making it an environmentally friendly and highly functional pretreatment material. This invention can be used for the rapid enrichment and detection of organophosphorus pesticides, while minimizing the impact of matrix effects on detection. It offers high detection speed, covers a wide range of pesticides, and enables high-throughput detection.

[0025] More preferably, the molecular weight of the polyethylene glycol selected is 1000-6000, the synthesis time at high temperature and high pressure in the reactor is 10-15 hours, and the synthesis temperature is 160-250°C.

[0026] Preferably, the molar ratio of the organophosphorus pesticide (dichlorvos and chlorpyrifos 1:1), methacrylic acid and trimethylolpropane trimethacrylate is preferably 1:2:2 to 1:4:10, the mechanical stirring time is 20 to 40 hours, and the temperature is 30 to 60°C.

[0027] The methanol:acetic acid = 9:1 (v / v) is used as the elution material until the template molecules are no longer detected in the final eluate. Alternatively, after the reaction is completed, the material can be ultrasonically eluted with ethanol until the template molecules are no longer detected in the final eluate.

[0028] The template molecules were eluted by ultrasonic elution with ethanol several times until they were no longer detected, and then dried in vacuum at 20-60°C.

[0029] The organophosphorus pesticide magnetic molecular imprinting material is used in identifying, adsorbing, separating and degrading organophosphorus pesticides in fruits and vegetables.

[0030] The magnetic molecular imprinting material for organophosphorus pesticides is coupled with LTP-MS to achieve rapid and high-throughput screening of pesticides in fruit and vegetable matrices.

[0031] The organophosphorus pesticide magnetic molecular imprinting material of the present invention can be coupled with LTP-MS to achieve rapid high-throughput screening of pesticides in fruit and vegetable matrices. The edible parts of different fruits and vegetables to be tested (including but not limited to apples, cauliflower, cabbage, carrots, cowpeas, cucumbers, winter dates, grapes, tomatoes, etc.) are crushed with a homogenizer, and the specific adsorption effect of magnetic molecular imprinting polymers on pesticides is used to quickly enrich the pesticides in the fruit and vegetable matrix onto the molecular imprinting material. Then, the molecular imprinting material that adsorbs pesticides is quickly separated from the fruit and vegetable matrix by a simple and convenient magnetic separation method rather than mechanical centrifugation. Due to the excellent magnetic properties of the material, this step can shorten the time from 10 minutes (mechanical centrifugation) to 30 seconds (magnetic separation). From the perspective of the convenience of the method and the separation time, the molecular imprinting method of the present invention is more suitable for on-site rapid processing scenarios. Afterwards, the separated molecular imprinting material is eluted with methanol and the eluate is collected. Because LTP technology involves passing an inert gas (helium, hydrogen, or nitrogen) into a glass tube and applying a 2.5-5 kV radio frequency voltage between electrodes to induce discharge in the barrier medium (the outer glass wall), the gas discharge forms a plasma. The carrier gas then blows out to form a probe-like low-temperature plasma, which directly impacts the surface of the sample to be tested for desorption and ionization, allowing for mass spectrometry analysis. Therefore, the eluate can be directly detected by LTP-MS for rapid analysis without passing it through a membrane, shortening the entire pretreatment process to approximately 40 minutes. Comparing the molecularly imprinted material-coupled LTP-MS method of the present invention with a method without pretreatment (direct extraction with the organic solvent acetonitrile), the OMMIPs method can increase the pesticide detection rate by 300% in some matrices, increasing the number of qualitative pesticide detections from 6 to 28 and from 12 to 23, fully demonstrating the excellent matrix purification effect of the molecularly imprinted material-coupled LTP-MS method of the present invention and effectively improving the pesticide detection rate.

[0032] The organophosphorus pesticide magnetic molecular imprinting material is used in the identification, adsorption, separation and degradation of organophosphorus pesticides in fruits and vegetables. The sample to be tested does not need to undergo tedious operations such as membrane filtering, and the pre-treatment time can be shortened to 35 minutes.

[0033] Beneficial effects:

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] (1) The imprinted material has a broad substrate adsorption spectrum and high adsorption capacity. The magnetic molecularly imprinted material of the present invention can rapidly and extensively adsorb a variety of organophosphorus pesticides, with maximum adsorption capacities for the template molecules chlorpyrifos and phoxim reaching 105 mg / g and 60 mg / g, respectively. Compared with previously reported molecularly imprinted materials for organophosphorus pesticides, the imprinted polymer of the present invention exhibits higher adsorption capacity.

[0036] (2) The imprinted material is magnetic and can achieve rapid separation of complex matrices. The present invention uses magnetic ferroferric oxide nanoparticles as the core of the molecular imprint. After surface modification, its magnetic properties are not affected. Under the action of an external magnetic field, the material can achieve rapid separation in complex matrices.

[0037] (3) The imprinted material exhibits the ability to rapidly degrade organic pollutants induced by light. The present invention inserts a layer of mesoporous titanium dioxide between the magnetic core and the imprinted layer. Because titanium dioxide can stimulate electron transitions under light conditions, generating electrons and holes for redox reactions, the imprinted polymer achieves efficient catalytic degradation of organophosphorus pesticides. Simultaneously, the imprinted space is released, enabling green in-situ regeneration of the material and improving its reusability.

[0038] (4) The imprinted material has good resistance to extreme environments. The material of the present invention has stable performance and can maintain the same adsorption performance for the target substrate in a wide range of pH (2-10) and temperature (5-45°C).

[0039] (5) The imprinted material has a short pre-treatment time in actual sample detection. Since the magnetic imprinted polymer of the present invention can reach adsorption equilibrium within 15 minutes for the adsorption of the target object, and utilizes its magnetic properties, the imprinted polymer can be separated from the matrix solution within 40 seconds through a controllable magnetic field. In addition, due to the optimization of subsequent detection methods, the sample to be tested does not need to undergo tedious operations such as membrane passing, and the pre-treatment time can be shortened to 35 minutes. Compared with existing pre-treatment methods, such as solid phase microextraction, matrix solid phase dispersion and supercritical fluid extraction, the application of the imprinted material of the present invention as a pre-treatment extract effectively solves the problems of long pre-treatment time and high consumption of organic reagents.

[0040] (6) The imprinted material can be coupled with low-temperature plasma mass spectrometry (LTP-MS) to achieve the goal of rapid and large-scale pesticide detection. LTP-MS in situ ionization mass spectrometry uses low-temperature plasma ionization technology to directly impact the surface of the sample to be tested for desorption and ionization. Through this mass spectrometry detection method, nearly 100 pesticides can be quickly detected within 5 seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Electron micrograph of the material in Example 1 of the present invention;

[0042] Figure 2 Electron micrograph of the material in Example 2 of the present invention;

[0043] Figure 3 Electron micrograph of the material in Example 3 of the present invention;

[0044] Figure 4 Electron micrograph of the material in Example 4 of the present invention;

[0045] Figure 5 Electron micrograph of the material in Example 5 of the present invention;

[0046] Figure 6 Isothermal adsorption curves of the imprinted polymer OMMIPs and the non-imprinted polymer MNIPs in Example 5 of the present invention;

[0047] Figure 7 Magnetic hysteresis loops of the imprinted polymer OMMIPs and the non-imprinted polymer MNIPs in Example 5 of the present invention;

[0048] Figure 8 Flow chart of the synthesis of imprinted polymer OMMIPs and their application in in situ ionization mass spectrometry detection of organophosphorus pesticides in Example 5 of the present invention;

[0049] Figure 9 Comparison of qualitative detection of pesticides in actual samples using imprinted polymer OMMIPs, QuEChERS, and no pretreatment methods in Example 5 of the present invention;

[0050] Figure 10 The reuse of the imprinted polymer OMMIPs in Example 5 of the present invention;

[0051] Figure 11 Comparative graph of pesticide degradation by imprinted polymers OMMIPs and C18 in Example 5 of the present invention;

[0052] Figure 12 Comparison of adsorption of imprinted polymer OMMIPs and non-imprinted OMNIPs at different temperatures and pH values ​​in Example 5 of the present invention. DETAILED DESCRIPTION

[0053] Example 1

[0054] Anhydrous sodium acetate, ferric chloride hexahydrate, and polyethylene glycol 2000 were dissolved in a mixed solution of ethylene glycol and diethylene glycol in a volume ratio of 1:10 at a molar ratio of 1:7:87. The mixed solution was transferred to a high-temperature and high-pressure reactor for further reaction at 200°C for 12 hours to obtain magnetic ferrosoferric oxide nanospheres.

[0055] 150 mg of the obtained Fe₃O₄ microspheres were dissolved in 100 mL of anhydrous ethanol at 45°C with mechanical stirring. 0.5 mL of aqueous ammonia was added, and 1 mL of tetrabutyl titanate dissolved in 20 mL of anhydrous ethanol was slowly added dropwise under nitrogen for 24 hours. After the reaction, the reactants were rinsed with anhydrous ethanol, redissolved in a mixture of 40 mL of ethanol and 20 mL of water, and transferred to a high-temperature, high-pressure reactor set at 160°C for 5 hours. The reaction yielded Fe₃O₄@mTiO₂ mesoporous titanium dioxide-coated magnetic beads.

[0056] The surface morphology of the materials in the present invention was characterized by using a transmission electron microscope. Figure 1 As shown, the ferroferric oxide microspheres are spherical with uniform particle size. The material has magnetic ferroferric oxide as the core and is coated with mesoporous titanium dioxide on the surface to form a shell with "light-induced" degradation properties. The thickness of the outer mesoporous titanium dioxide layer is 20nm.

[0057] Example 2

[0058] Anhydrous sodium acetate, ferric chloride hexahydrate, and polyethylene glycol 2000 were dissolved in a mixture of ethylene glycol and diethylene glycol (1:10 by volume) at a molar ratio of 1:7:87. The mixture was then transferred to a high-temperature, high-pressure reactor and allowed to react at 200°C for 12 hours. After the reaction was complete, magnetic ferrosoferric oxide nanospheres were obtained.

[0059] 100 mg of the obtained Fe₃O₄ microspheres were dissolved in 100 mL of anhydrous ethanol at 45°C with mechanical stirring. 0.5 mL of aqueous ammonia was added, and 1 mL of tetrabutyl titanate dissolved in 20 mL of anhydrous ethanol was slowly added dropwise. The reaction was allowed to proceed under nitrogen for 24 hours. After the reaction, the reactants were rinsed with anhydrous ethanol, redissolved in a mixture of 40 mL of ethanol and 20 mL of water, and transferred to a high-temperature, high-pressure reactor set at 160°C for 5 hours. The reaction yielded Fe₃O₄@mTiO₂ mesoporous titanium dioxide-coated magnetic beads.

[0060] The surface morphology of the materials in the present invention was characterized by using a transmission electron microscope. Figure 2 As shown, the ferroferric oxide microspheres are spherical with uniform particle size. The material has magnetic ferroferric oxide as the core and is coated with mesoporous titanium dioxide on the surface to form a shell with "light-induced" degradation properties. The thickness of the outer mesoporous titanium dioxide layer is 50nm.

[0061] The electron microscope images of the materials obtained in Example 1 and Example 2 are as follows: Figure 1 and Figure 2As shown in the figure, the thickness of the surface mesoporous titanium dioxide layer varies depending on the amount of ferroferric oxide microspheres added. When the magnetic microspheres are added at 100 mg, the mesoporous titanium dioxide layer is thicker, creating more cavities and more binding sites that facilitate the formation of the imprinted layer. Therefore, 100 mg was selected as the actual amount of ferroferric oxide microspheres added.

[0062] Example 3

[0063] Anhydrous sodium acetate, ferric chloride hexahydrate, and polyethylene glycol were dissolved in a mixture of ethylene glycol and diethylene glycol (1:10 by volume) in a molar ratio of 1:7:87. The mixture was then transferred to a high-temperature, high-pressure reactor and continued to react at 200°C for 12 hours. After the reaction, magnetic ferroferric oxide nanospheres were obtained. 100 mg of the obtained ferroferric oxide microspheres were dissolved in 100 mL of anhydrous ethanol at 45°C with mechanical stirring. An appropriate amount of aqueous ammonia was added, and tetrabutyl titanate dissolved in anhydrous ethanol was slowly added dropwise. The reaction was allowed to proceed under nitrogen for 24 hours. After the reaction, the reactants were rinsed with anhydrous ethanol, redissolved in a mixture of ethanol and water, and transferred to a high-temperature, high-pressure reactor at 160°C for 5 hours. The resulting Fe3O4@mTiO2 mesoporous titanium dioxide-coated magnetic beads were obtained.

[0064] 150mg of Fe3O4@mTiO2 was dissolved in 100mL of toluene at 60-90°C with mechanical stirring. Meanwhile, 80µL of methoxysilane dissolved in 20mL of toluene was slowly added dropwise to the reaction mixture under nitrogen for 3 hours. After the reaction, the mixture was rinsed with anhydrous ethanol and dried in a vacuum oven until ready for use, yielding Fe3O4@mTiO2@MPS.

[0065] The organophosphorus pesticides dichlorvos, phoxim, and methacrylic acid were dissolved in acetonitrile at a molar ratio of 1:1:6 and prepolymerized in a refrigerator at 4°C for 12 hours. 300 mg of Fe₃O₄@mTiO₂@MPS was then added and allowed to react at 30°C for 1 hour. 10 mmol of ethylene glycol dimethacrylate and 150 mg of azobisisobutyronitrile were then added to the reaction, with a template molecule:functional monomer:crosslinker ratio of 1:6:10. The reaction was continued at 50°C for 6 hours. Finally, the reaction was terminated by maintaining the temperature at 60°C for 24 hours. The material was washed with methanol:acetic acid (9:1 v / v) to prevent the detection of the organophosphorus pesticide template molecule. The material was then vacuum dried to obtain the organophosphorus pesticide magnetic molecularly imprinted material. The synthesis of the non-imprinted polymer and the imprinted polymer was identical, except that the template molecule was omitted.

[0066] Electron microscope images of materials Figure 3As shown in the figure, some of the imprinted particles are agglomerated, while others are not coated with the imprinting layer. The material consists of a magnetic ferrosoferric oxide core coated with mesoporous titanium dioxide to form a shell with "light-induced" degradation properties. Double-bond modification, using methacrylic acid as a functional monomer and dichlorvos and phoxim as dual template molecules, is carried out through surface polymerization under the action of a TRIM crosslinker, forming a novel "core-shell" magnetic molecularly imprinted polymer with a particle size of approximately 370 nm.

[0067] The experiment used a 10mL clean stoppered centrifuge tube, added 10mg of OMMIPs (or OMNIPs) and 5mL of different concentrations of dichlorvos and phoxim, and set the concentration range to 0.1~3.0mM. After sealing the centrifuge tube, the mixture was thoroughly mixed and shaken at 25℃ and 190rpm for 24h. After the reaction, the OMMIPs (or OMNIPs) were magnetically separated, the supernatant was collected, and the experiment was repeated twice. The detection of organophosphorus pesticides was carried out by ultraviolet spectrophotometry and ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry, and phoxim was detected at a wavelength of 285nm. The detection conditions of dichlorvos mass spectrometry are: the mobile phase is 0.1% formic acid water and acetonitrile. The adsorption equilibrium capacity Q of the polymer material for the template molecule is calculated by the following formula. e (mg g -1 ).

[0068]

[0069] Where C0 is the concentration of the configured target adsorbate, C1 is the measured concentration of the target adsorbate, and M is the molar mass of the target (g mol -1 ), V is the volume of the adsorption target added (mL), and m is the mass of the imprinted polymer added (mg).

[0070] Adsorption tests of the molecularly imprinted nanopolymer and non-imprinted polymer prepared in this example showed an adsorption capacity of 7.94 mg / g for dichlorvos, corresponding to an imprinting factor of 2.14. The adsorption capacity for phoxim was 30.28 mg / g, corresponding to an imprinting factor of 1.29. The imprinting factor is calculated as the adsorption capacity of the imprinted polymer for the target substance divided by the adsorption capacity of the imprinted polymer for the target substance.

[0071] Example 4

[0072] Anhydrous sodium acetate, ferric chloride hexahydrate, and polyethylene glycol were dissolved in a mixture of ethylene glycol and diethylene glycol (1:10 by volume) in a molar ratio of 1:7:87. The mixture was then transferred to a high-temperature, high-pressure reactor and continued to react at 200°C for 12 hours. After the reaction, magnetic ferroferric oxide nanospheres were obtained. 100 mg of the obtained ferroferric oxide microspheres were dissolved in 100 mL of anhydrous ethanol at 45°C with mechanical stirring. An appropriate amount of aqueous ammonia was added, and tetrabutyl titanate dissolved in anhydrous ethanol was slowly added dropwise. The reaction was allowed to proceed under nitrogen for 24 hours. After the reaction, the reactants were rinsed with anhydrous ethanol, redissolved in a mixture of ethanol and water, and transferred to a high-temperature, high-pressure reactor at 160°C for 5 hours. The resulting Fe3O4@mTiO2 mesoporous titanium dioxide-coated magnetic beads were obtained.

[0073] 150mg of Fe3O4@mTiO2 was dissolved in 100mL of toluene at 60-90°C with mechanical stirring. Meanwhile, 80µL of methoxysilane dissolved in 20mL of toluene was slowly added dropwise to the reaction mixture under nitrogen for 3 hours. After the reaction, the mixture was rinsed with anhydrous ethanol and dried in a vacuum oven until ready for use, yielding Fe3O4@mTiO2@MPS.

[0074] The organophosphorus pesticides dichlorvos, phoxim, and methacrylic acid were dissolved in acetonitrile at a molar ratio of 1:1:6 and prepolymerized in a refrigerator at 4°C for 12 hours. 300 mg of Fe₃O₄@mTiO₂@MPS was then added and reacted at 30°C for 1 hour. 20 mmol of ethylene glycol dimethacrylate and 150 mg of azobisisobutyronitrile were then added to the reaction, with a ratio of template molecule:functional monomer:crosslinker of 1:6:20. The reaction was continued at 50°C for 6 hours. Finally, the reaction was maintained at 60°C for 24 hours before termination. The material was washed with methanol:acetic acid (9:1 v / v) to prevent the detection of the organophosphorus pesticide template molecule. The material was then vacuum dried to obtain the organophosphorus pesticide magnetic molecularly imprinted material. The synthesis of the non-imprinted polymer was identical to that of the imprinted polymer, except that the template molecule was omitted.

[0075] Electron microscope images of materials Figure 4 As shown in the figure, the increased crosslinker ratio leads to severe agglomeration between the imprinted particles. The material consists of a magnetic ferrosoferric oxide core coated with mesoporous titanium dioxide to form a shell with "light-induced" degradation properties. Double-bond modification, using methacrylic acid as a functional monomer and dichlorvos and phoxim as dual template molecules, allows for surface polymerization under the action of the TRIM crosslinker, resulting in a novel "core-shell" magnetic molecularly imprinted polymer with a particle size of approximately 510 nm.

[0076] The experiment used a 10mL clean stoppered centrifuge tube, added 10mg of OMMIPs (or OMNIPs) and 5mL of different concentrations of dichlorvos and phoxim, and set the concentration range to 0.1~3.0mM. After sealing the centrifuge tube, the mixture was thoroughly mixed and shaken at 25℃ and 190rpm for 24h. After the reaction, the OMMIPs (or OMNIPs) were magnetically separated, the supernatant was collected, and the experiment was repeated twice. The detection of organophosphorus pesticides was carried out by ultraviolet spectrophotometry and ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry, and phoxim was detected at a wavelength of 285nm. The detection conditions of dichlorvos mass spectrometry are: the mobile phase is 0.1% formic acid water and acetonitrile. The adsorption equilibrium capacity Q of the polymer material for the template molecule is calculated by the following formula. e (mg g -1 ).

[0077]

[0078] Where C0 is the concentration of the configured target adsorbate, C1 is the measured concentration of the target adsorbate, and M is the molar mass of the target (g mol -1 ), V is the volume of the adsorption target added (mL), and m is the mass of the imprinted polymer added (mg).

[0079] Adsorption tests were conducted on the molecularly imprinted nanopolymer and non-imprinted polymer prepared in this example. The adsorption capacity for phoxim was 41.22 mg / g, corresponding to an imprinting factor of 1.1. The adsorption capacity for dichlorvos was 5.93 mg / g, corresponding to an imprinting factor of 2.24. The imprinting factor is calculated as the adsorption capacity of the imprinted polymer on the target substance divided by the adsorption capacity of the imprinted polymer on the target substance.

[0080] Example 5

[0081] Anhydrous sodium acetate, ferric chloride hexahydrate, and polyethylene glycol were dissolved in a mixture of ethylene glycol and diethylene glycol (1:10 by volume) in a molar ratio of 1:7:87. The mixture was then transferred to a high-temperature, high-pressure reactor and continued to react at 200°C for 12 hours. After the reaction, magnetic ferroferric oxide nanospheres were obtained. 100 mg of the obtained ferroferric oxide microspheres were dissolved in 100 mL of anhydrous ethanol at 45°C with mechanical stirring. An appropriate amount of aqueous ammonia was added, and tetrabutyl titanate dissolved in anhydrous ethanol was slowly added dropwise. The reaction was allowed to proceed under nitrogen for 24 hours. After the reaction, the reactants were rinsed with anhydrous ethanol, redissolved in a mixture of ethanol and water, and transferred to a high-temperature, high-pressure reactor at 160°C for 5 hours. The resulting Fe3O4@mTiO2 mesoporous titanium dioxide-coated magnetic beads were obtained.

[0082] 150mg of Fe3O4@mTiO2 was dissolved in 100mL of toluene at 60-90°C with mechanical stirring. Meanwhile, 80µL of methoxysilane dissolved in 20mL of toluene was slowly added dropwise to the reaction mixture under nitrogen for 3 hours. After the reaction, the mixture was rinsed with anhydrous ethanol and dried in a vacuum oven until ready for use, yielding Fe3O4@mTiO2@MPS.

[0083] The organophosphorus pesticides dichlorvos, chlorpyrifos, and methacrylic acid were dissolved in acetonitrile at a molar ratio of 1:3 and prepolymerized in a refrigerator at 4°C for 12 hours. 200 mg of Fe₃O₄@mTiO₂@MPS was then added and reacted at 30°C for 1 hour. 10 mmol of trimethylolpropane trimethacrylate and 150 mg of azobisisobutyronitrile were then added to the reaction, with a ratio of template molecule:functional monomer:crosslinker of 1:3:5. The reaction was continued at 50°C for 6 hours. Finally, the reaction was terminated by maintaining the temperature at 60°C for 24 hours. The material was washed with methanol:acetic acid (9:1 v / v) to prevent the detection of the organophosphorus pesticide template molecule. The material was then vacuum dried to obtain the organophosphorus pesticide magnetic molecularly imprinted material. The synthesis of the non-imprinted polymer was identical to that of the imprinted polymer, except that the template molecule was omitted.

[0084] Electron microscope images of materials Figure 5 As shown in the figure, the imprinted particles are well dispersed and form a uniform imprinted layer on the outside. The material consists of a magnetic ferrosoferric oxide core coated with mesoporous titanium dioxide to form a shell with "light-induced" degradation properties. Double-bond modification, using methacrylic acid as a functional monomer and dichlorvos and phoxim as dual template molecules, is carried out through surface polymerization under the action of a TRIM crosslinker, forming a novel "core-shell" magnetic molecularly imprinted polymer with a particle size of approximately 300 nm.

[0085] The experiment used a 10mL clean stoppered centrifuge tube, added 10mg of OMMIPs (or OMNIPs) and 5mL of different concentrations of dichlorvos and chlorpyrifos, and set the concentration range to 0.1~3.0mM. After sealing the centrifuge tube, the mixture was thoroughly mixed and shaken at 25℃ and 190rpm for 24h. After the reaction, the OMMIPs (or OMNIPs) were magnetically separated, the supernatant was collected, and the experiment was repeated twice. The detection of organophosphorus pesticides was performed by ultraviolet spectrophotometry and ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry, and chlorpyrifos was detected at a wavelength of 289nm. The dichlorvos mass spectrometry detection conditions are: the mobile phase is 0.1% formic acid water and acetonitrile. The adsorption equilibrium capacity Q of the polymer material for the template molecule is calculated by the following formula e (mg g -1 ).

[0086]

[0087] Where C0 is the concentration of the configured target adsorbate, C1 is the measured concentration of the target adsorbate, and M is the molar mass of the target (g mol -1 ), V is the volume of the adsorption target added (mL), and m is the mass of the imprinted polymer added (mg).

[0088] The molecularly imprinted nanopolymer and non-imprinted polymer prepared in this example were subjected to adsorption tests. The adsorption capacity of chlorpyrifos was 83.8 mg / g, and the corresponding imprinting factor was 1.22. The adsorption capacity of dichlorvos was 13.09 mg / g, and the corresponding imprinting factor was 1.51. The imprinting factor is calculated as the adsorption capacity of the imprinted polymer on the target object divided by the adsorption capacity of the imprinted polymer on the target object. The results are shown in Figure 2. Figure 6 As shown, there is a significant difference in the adsorption of targets between the imprinted and non-imprinted polymers. This indicates that a large number of template molecule recognition sites have been formed on the magnetic molecularly imprinted polymer. However, the surface of the non-imprinted polymer lacks three-dimensional imprinted pores, and nonspecific adsorption is predominant. Consequently, there is a difference in adsorption capacity compared to the imprinted material. * in the figure indicates a significant difference in the adsorption capacity of targets between the imprinted and non-imprinted polymers.

[0089] Example 6

[0090] The Fe3O4, Fe3O4@mTiO2 and organophosphorus pesticide magnetic molecular imprinted materials (OMMIPs) prepared in Example 5 were used as samples to perform hysteresis intensity detection using a vibrating sample magnetometer (VSM) from LakeShore, USA.

[0091] The results are as follows Figure 7 As shown in the figure, the hysteresis loops of Fe3O4, Fe3O4@mTiO2 and OMMIPs all pass through zero, which indicates that the materials have no hysteresis and exhibit good superparamagnetism at room temperature. Among them, the saturation magnetization intensity of Fe3O4 is 83.9emu g -1 The saturation magnetization of Fe3O4@mTiO2 is 61.1emu g -1 The saturation magnetization of OMMIPs is 22.9 emu g -1 And the saturation magnetization of Fe3O4 (83.9emu g -1 ) is higher than Fe3O4@mTiO2(61.1emu g -1 ) and MMIPs(22.9emu g -1) indicates that with each modification step, the superparamagnetic material is gradually surrounded by layers of non-magnetic material, and the saturation magnetization intensity continues to decrease, resulting in a weakening of magnetism. However, under the action of an external magnetic field, MMIPs can still be easily separated from the solution, meeting the experimental requirements. Figure 7 As shown in the illustration, the magnetic field strength provided by the small magnet is sufficient to separate the magnetic material from the solution, and the separation time is about 30 seconds.

[0092] Example 7

[0093] Anhydrous sodium acetate, ferric chloride hexahydrate, and polyethylene glycol were dissolved in a mixture of ethylene glycol and diethylene glycol (1:10 by volume) in a molar ratio of 1:7:87. The mixture was then transferred to a high-temperature, high-pressure reactor and continued to react at 200°C for 12 hours. After the reaction, magnetic ferroferric oxide nanospheres were obtained. 100 mg of the obtained ferroferric oxide microspheres were dissolved in 100 mL of anhydrous ethanol at 45°C with mechanical stirring. An appropriate amount of aqueous ammonia was added, and tetrabutyl titanate dissolved in anhydrous ethanol was slowly added dropwise. The reaction was allowed to proceed under nitrogen for 24 hours. After the reaction, the reactants were rinsed with anhydrous ethanol, redissolved in a mixture of ethanol and water, and transferred to a high-temperature, high-pressure reactor at 160°C for 5 hours. The resulting Fe3O4@mTiO2 mesoporous titanium dioxide-coated magnetic beads were obtained.

[0094] 150mg of Fe3O4@mTiO2 was dissolved in 100mL of toluene at 60-90°C with mechanical stirring. Meanwhile, 80µL of methoxysilane dissolved in 20mL of toluene was slowly added dropwise to the reaction mixture under nitrogen for 3 hours. After the reaction, the mixture was rinsed with anhydrous ethanol and dried in a vacuum oven until ready for use, yielding Fe3O4@mTiO2@MPS.

[0095] The organophosphorus pesticides dichlorvos, chlorpyrifos, and methacrylic acid were dissolved in acetonitrile at a molar ratio of 1:1:3 and prepolymerized in a refrigerator at 4°C for 12 hours. 200 mg of Fe₃O₄@mTiO₂@MPS was then added and allowed to react at 30°C for 1 hour. 10 mmol of trimethylolpropane trimethacrylate and 150 mg of azobisisobutyronitrile were then added to the reaction, with a template molecule:functional monomer:crosslinker ratio of 1:3:5. The reaction was continued at 50°C for 6 hours. Finally, the reaction was terminated by maintaining the temperature at 60°C for 24 hours. The material was washed with methanol:acetic acid (9:1 v / v) to prevent the detection of the organophosphorus pesticide template molecule. The material was then vacuum dried to obtain the organophosphorus pesticide magnetic molecularly imprinted material. The synthesis of the non-imprinted polymer and the imprinted polymer was identical, except that the template molecule was omitted.

[0096] OMMIPs method: Take the edible parts of 9 different fruits and vegetables (apple, cauliflower, cabbage, carrot, cowpea, cucumber, winter jujube, grape, tomato) and grind them into powder using a homogenizer for mixing. Take 4g of sample in a 15mL centrifuge tube, add 40uL of pesticide standard (according to the Chinese national standard GB 2763-2021, sample source: Alta Technology Co., Ltd.) and 4mL of methanol, mix well and let it stand for 15 minutes. Then add 4mL of water, mix well, add 40mg of organophosphorus pesticide magnetic molecular imprinting material (OMMIPs), shake and adsorb for 15 minutes, collect the material by magnetic separation, and elute the material with 500uL of acetonitrile for 5 times. Combine the eluates to obtain the test solution.

[0097] QuEChERS method: Take the edible parts of 9 different fruits and vegetables (apple, cauliflower, cabbage, carrot, cowpea, cucumber, winter jujube, grape, tomato) and grind them into powder using a homogenizer for later use. Take 4g of sample in a 15mL centrifuge tube, add 40uL of pesticide standard (according to Chinese national standard GB 2763-2021, sample source: Alta Technology Co., Ltd.) and 4mL of acetonitrile, mix well and let it stand for 15 minutes. Add 0.8g of anhydrous magnesium sulfate and 0.2g of sodium chloride (commercial salt bag), shake and mix for 1 minute, centrifuge at 8000r / min for 10 minutes, and collect the supernatant for purification. Add 25mg of ethylenediamine-N-propylsilane (PSA), 150mg of anhydrous magnesium sulfate and 25mg of C18 (commercial salt bag) to the supernatant. After shaking for 1 minute, centrifuge at 8000r / min for 5 minutes, and collect the supernatant as the test solution.

[0098] Acetonitrile direct extraction method: The edible portions of nine different fruits and vegetables (apple, cauliflower, cabbage, carrot, cowpea, cucumber, winter jujube, grape, and tomato) were homogenized and mixed thoroughly. 4 g of sample was placed in a 15 mL centrifuge tube. 40 μL of pesticide standard (according to Chinese National Standard GB 2763-2021, sourced from Alta Technology Co., Ltd.) and 4 mL of acetonitrile were added. Mix thoroughly and allow to stand for 15 minutes. Centrifuge at 8000 rpm for 10 minutes, and the supernatant was collected as the test solution.

[0099] LTP-MS was used for detection, and the results were as follows Figure 9As shown in Table 1, the numerical values ​​represent the proportion of pesticides detectable by each method relative to the total number of pesticides in the corresponding matrix. Across nine fruit and vegetable matrices, the number of pesticides detected after OMMIPs enrichment and using the QuEChERS pretreatment method was significantly greater than that detected by direct acetonitrile extraction, demonstrating that OMMIPs, as a pretreatment material, can mitigate matrix effects and significantly improve pesticide detection rates. The pretreatment method, which involves enrichment with MMIPs followed by elution, achieves a detection range similar to that of the QuEChERS method and far exceeds that of direct extraction. Combining the two methods allows for rapid qualitative detection of the vast majority of pesticides.

[0100] Example 8

[0101] The organophosphorus pesticide magnetic molecular imprinting material (OMMIPs) prepared in Example 5 was used as the adsorption material. A 10 mL clean stoppered centrifuge tube was selected for the experiment, and 10 mg of OMMIPs and 5 mL of dichlorvos and chlorpyrifos (1 mM / L) were added. After sealing the centrifuge tube, the mixture was thoroughly mixed and shaken at 25°C and 190 rpm for 24 hours. After the reaction was completed, the OMMIPs were magnetically separated and the supernatant was collected. The detection of organophosphorus pesticides was performed by ultraviolet spectrophotometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry, and chlorpyrifos was detected at a wavelength of 289 nm. The dichlorvos mass spectrometry detection conditions were: the mobile phase was 0.1% formic acid water and acetonitrile. The adsorption equilibrium capacity Q of the polymer material for the template molecule was calculated by the following formula e (mg g -1 ).

[0102]

[0103] Where C0 is the concentration of the configured target adsorbate, C1 is the measured concentration of the target adsorbate, and M is the molar mass of the target (g mol -1 ), V is the volume of the adsorption target added (mL), and m is the mass of the imprinted polymer added (mg).

[0104] The used material was eluted until the target adsorbate could no longer be detected in the last eluate. The above experiment was repeated five times with the recovered material. Figure 10 As shown in the figure, after five cycles, the OMMIPs still maintained 94.6% and 98.47% of their initial adsorption capacities for chlorpyrifos and dichlorvos, respectively. This demonstrates the high stability of the synthesized material and its ability to be recycled multiple times, significantly reducing costs.

[0105] A mixture of 19 pesticides (Alta Technology Co., Ltd., catalog number: 1ST020003-A) and a mixture of 39 pesticides (Alta Technology Co., Ltd., catalog number: 1ST020019-A) were diluted 100 times and dissolved in a methanol: water = 5:5 (v / v) mixed solution. 10 mg of OMMIPs material was dissolved in 10 mL of pesticide solution, shaken and mixed, and allowed to stand for 10 minutes. After magnetic separation of the imprinted material, it was redissolved in 5 mL of water and placed in a 6-well ELISA plate for UV exposure. After 3 hours, the imprinted material was magnetically separated, eluted, and the supernatant was collected. The pesticide content in the solution was determined using TQ-MS, and the degradation rate was calculated. The degradation rate of the C18 material for the mixed drug was calculated using the same experimental method for comparison. The results are as follows. Figure 11 As shown, "#" represents a highly toxic or restricted pesticide, "*" indicates a significant difference in the degradation rate between OMMIPs and C18, and "nd" indicates not detected. OMMIPs achieved degradation rates exceeding 80% for most pesticides, significantly exceeding the degradation rate of C18. The above experiments demonstrate the material's excellent reusability and efficient pesticide degradation, demonstrating the green in-situ regeneration of the imprinted material after catalytic degradation of organophosphorus pesticides, enabling its reuse.

[0106] Example 9

[0107] The organophosphorus pesticide magnetic molecular imprinting material (OMMIPs) and non-imprinting material (OMNIPs) prepared in Example 5 were used as adsorption materials respectively. A 10 mL clean stoppered centrifuge tube was selected for the experiment, and 10 mg of OMMIPs and 5 mL of dichlorvos and chlorpyrifos (1 mM / L) were added. After sealing the centrifuge tube, the mixture was thoroughly mixed and shaken at 5°C, 15°C, 25°C, 35°C, 45°C, and 190 rpm for 24 hours. After the reaction was completed, the OMMIPs were magnetically separated and the supernatant was collected. The detection of organophosphorus pesticides was performed by ultraviolet spectrophotometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry, and chlorpyrifos was detected at a wavelength of 289 nm. The dichlorvos mass spectrometry detection conditions were: the mobile phase was 0.1% formic acid water and acetonitrile. The adsorption equilibrium capacity Q of the polymer material for the template molecule was calculated by the following formula e (mg g -1 ).

[0108]

[0109] Where C0 is the concentration of the configured target adsorbate, C1 is the measured concentration of the target adsorbate, and M is the molar mass of the target (g mol -1 ), V is the volume of the adsorption target added (mL), and m is the mass of the imprinted polymer added (mg).

[0110] The organophosphorus pesticide magnetic molecular imprinting material (OMMIPs) (or OMNIPs) prepared in Example 5 was used as the adsorption material. A 10 mL clean stoppered centrifuge tube was selected for the experiment. 10 mg of OMMIPs and 5 mL of dichlorvos and chlorpyrifos (1 mM / L) were added, and the pH was adjusted to 2, 4, 6, 8, and 10. After the centrifuge tube was sealed, the mixture was thoroughly mixed and shaken at 25°C and 190 rpm for 24 hours. After the reaction was completed, the OMMIPs were magnetically separated and the supernatant was collected. The detection of organophosphorus pesticides was performed by ultraviolet spectrophotometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry, and chlorpyrifos was detected at a wavelength of 289 nm. The dichlorvos mass spectrometry detection conditions were: the mobile phase was 0.1% formic acid water and acetonitrile. The adsorption equilibrium capacity Q of the polymer material for the template molecule was calculated by the following formula e (mg g -1 ).

[0111]

[0112] Where C0 is the concentration of the configured target adsorbate, C1 is the measured concentration of the target adsorbate, and M is the molar mass of the target (g mol -1 ), V is the volume of the adsorption target added (mL), and m is the mass of the imprinted polymer added (mg).

[0113] After testing, the results were Figure 12 A and Figure 12 As shown in Figure B, the adsorption capacity of OMMIPs and OMNIPs increases with increasing temperature from 5 to 45°C. This is because the increased temperature increases the collision probability between the adsorbent and the adsorbate, accelerating the adsorption reaction. However, this does not affect the adsorption performance of the target adsorbate at different ambient temperatures. The adsorption capacity of OMMIPs and OMNIPs is relatively stable within the pH range of 2 to 10.

[0114] Table 1 Statistics of detection results of nine matrices with different pretreatment methods Note: “√” means detected (judged as positive), blank means not detected (judged as negative)

[0115]

[0116]

[0117]

Claims

1. A magnetic molecular imprinted material for organophosphorus pesticides with broad-spectrum enrichment and degradation, characterized in that The material uses magnetic ferrosoferric oxide as the core and is coated with mesoporous titanium dioxide on the surface to form a shell with "light-induced" degradation properties. It is further modified with double bonds, uses methacrylic acid as the functional monomer, and uses dichlorvos and chlorpyrifos as dual template molecules. Surface polymerization is carried out under the action of TRIM crosslinking agent to form a new type of "core-shell" structured magnetic molecularly imprinted polymer.

2. The magnetic molecularly imprinted material for organophosphorus pesticides with broad-spectrum enrichment and degradation according to claim 1, characterized in that: The magnetic molecular imprinted particle size is 200-300 nm and has good magnetic characteristics.

3. The magnetic molecular imprinted material for organophosphorus pesticides with broad-spectrum enrichment and degradation according to claim 1, characterized in that The ratio of the magnetic molecular imprinting material template molecule: functional monomer: cross-linking agent is in the range of 1:1:1 to 1:10:

20.

4. A method for preparing a magnetic molecularly imprinted material for an organophosphorus pesticide, comprising the following steps: Step 1: dissolving anhydrous sodium acetate, ferric chloride hexahydrate, and polyethylene glycol in a molar ratio of 1:1:10 to 1:10:100 in a mixed solution of ethylene glycol and diethylene glycol in a volume ratio of 1:5 to 1:20, transferring the mixed solution to a high-temperature and high-pressure reactor and continuing the reaction at a temperature of 150 to 250° C. for 5 to 15 hours; after the reaction is completed, magnetic ferrosoferric oxide nanospheres are obtained; Step 2: Dissolve 50-200 mg of ferroferric oxide microspheres in 80-130 mL of anhydrous ethanol, stir mechanically at 30-50 °C, add 0.5-2 mL of ammonia water, and slowly drip 0.5-2 mL of tetrabutyl titanate dissolved in anhydrous ethanol. Protect the reaction with nitrogen for 20-30 hours. After the reaction is completed, rinse the reactants with anhydrous ethanol, redissolve them in a mixed solution of ethanol and water, transfer them to a high-temperature and high-pressure reactor, set the temperature to 120-170 °C, and the reaction time is 5-10 hours. After the reaction is completed, Fe3O4@mTiO2 mesoporous titanium dioxide-coated magnetic beads are obtained. Step 3: Dissolve 100-200 mg of Fe3O4@mTiO2 in toluene and mechanically stir at 60-90°C. Simultaneously, slowly add 50-200 μL of methoxysilane and triethylamine dissolved in toluene to the mixture. Under nitrogen protection, allow the mixture to react for 2-5 hours. After the reaction is complete, rinse the mixture with anhydrous ethanol and dry it in a vacuum drying oven to obtain Fe3O4@mTiO2@MPS. Step 4: The organophosphorus pesticides dichlorvos, chlorpyrifos and methacrylic acid are dissolved in acetonitrile in a certain ratio of 1:1:1 to 1:10:10, prepolymerized in a refrigerator at 4°C for 10 to 20 hours, and then 100 to 300 mg of Fe3O4@mTiO2@MPS is added and reacted at 20 to 40°C for 1 to 2 hours; then 7 to 15 mmol of trimethylolpropane trimethacrylate and 100 to 300 mg of azobisisobutyronitrile are added to the reaction and reacted at 40 to 60°C for 5 to 10 hours; finally, the reaction is maintained at 50 to 70°C for 24 hours to terminate the reaction, and the material is washed with methanol and acetic acid until the organophosphorus pesticide template molecules are no longer detected, and vacuum dried to obtain the organophosphorus pesticide magnetic molecular imprinting material.

5. The method for preparing the organophosphorus pesticide magnetic molecular imprinted material according to claim 4, characterized in that: The molecular weight of the selected polyethylene glycol is 1000-6000, the synthesis time at high temperature and high pressure in the reactor is 10-15 h, and the synthesis temperature is 160-250°C.

6. The method for preparing the organophosphorus pesticide magnetic molecular imprinted material according to claim 4, characterized in that: The molar ratio of the organophosphorus pesticide, methacrylic acid and trimethylolpropane trimethacrylate is 1:2:2 to 1:4:

10.

7. The method for preparing the organophosphorus pesticide magnetic molecular imprinted material according to claim 4, characterized in that: In step 4, the methanol:acetic acid = 9:1 (v / v) is used as the elution material until the template molecule is no longer detected in the last eluate.

8. The method for preparing the organophosphorus pesticide magnetic molecular imprinted material according to claim 4, characterized in that: In step 4, vacuum drying is performed at 20-60°C.

9. Use of the magnetic molecular imprinted material for organophosphorus pesticides according to any one of claims 1 to 3 in identifying, adsorbing, separating and degrading organophosphorus pesticides in fruits and vegetables.

10. The use according to claim 9, wherein the magnetic molecular imprinting material for organophosphorus pesticides is coupled with LTP-MS to achieve rapid high-throughput screening of pesticides in fruit and vegetable matrices.

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