Preparation method and application of molecularly imprinted material selectively adsorbing metalaxyl

Abstract

The present application relates to the field of analytical chemistry and pollutant analysis and detection technology, and particularly relates to a preparation method of a molecularly imprinted polymer material selectively adsorbing metalaxyl and application thereof. The preparation method comprises the following steps: mixing a template molecule with a porogen and a functional monomer, and performing a pre-polymerization reaction to obtain a pre-polymerization product; adding a crosslinking agent and an initiator to the pre-polymerization product, and performing a polymerization reaction under a protective atmosphere to obtain a polymerization product; and removing the template molecule from the polymerization product to obtain the molecularly imprinted polymer material selectively adsorbing metalaxyl. The present application utilizes the interaction force generated by the functional monomer and the template molecule, and under the action of the crosslinking agent, generates a polymer with a three-dimensional network space structure. After the template molecule is eluted, cavities which can match the space size of metalaxyl and generate interaction force are exposed, so that selective recognition and detection of metalaxyl and other phenylamide drugs are realized.

Description

Technical Field

[0001] This invention relates to the fields of analytical chemistry and pollutant analysis and detection technology, specifically to a method for preparing a molecularly imprinted polymer material that selectively adsorbs metalaxyl and its application. Background Technology

[0002] Metalaxyl is a broad-spectrum, highly effective phenylamide fungicide widely used in pesticide and veterinary drug forms to treat various animal and plant diseases caused by fungal infections. In aquaculture, metalaxyl, as an alternative to the banned drug malachite green, is mainly used to prevent and treat freshwater fish diseases caused by fungal infections such as Saprolegnia. It is currently the only approved antifungal drug among veterinary drugs for aquaculture. To prevent potential problems related to aquatic product quality and safety and ecological environment safety due to the improper use of metalaxyl, strengthening the monitoring and residue analysis of metalaxyl in aquatic products and aquaculture environments is important and urgent.

[0003] The commonly used pretreatment method for metalaxyl detection is solid phase extraction (SPE). The core of this method lies in the performance of the adsorbent material. Traditional adsorbent materials have disadvantages such as low selectivity and poor adsorption.

[0004] Currently, a metalaxyl molecularly imprinted electrochemical sensor has been successfully developed. However, there are no relevant literature reports on the preparation of molecularly imprinted polymer materials that selectively adsorb metalaxyl and their selective identification and detection of metalaxyl and its homologues in aquaculture environments and agricultural food products. Summary of the Invention

[0005] In view of the shortcomings of the prior art, this invention provides a method for preparing a molecularly imprinted polymer material that selectively adsorbs metalaxyl and its application, which can solve the problems of low selectivity and poor adsorption capacity of solid-phase extraction adsorption materials used in the pretreatment stage of metalaxyl detection. The virtual template method used in the synthesis process can effectively avoid the influence of incomplete elution of template molecules during imprinting on the quantitative analysis results.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] The first objective of this invention is to provide a method for preparing a molecularly imprinted polymer material that selectively adsorbs metalaxyl, specifically comprising the following steps:

[0008] A template molecule solution is obtained by mixing template molecules with a porogen.

[0009] The template molecule solution is mixed with the functional monomer to carry out a prepolymerization reaction to obtain the prepolymer product;

[0010] A crosslinking agent and an initiator are added to the prepolymer product, and a polymerization reaction is carried out under a protective atmosphere to obtain the polymer product;

[0011] The polymerization product was eluted using a template remover to remove template molecules from the polymerization product, resulting in a molecularly imprinted polymer material that selectively adsorbs metalaxyl.

[0012] Optionally, the template molecule is at least one of metalaxyl, benzalkonium chloride, oxazolium, and furazolidone.

[0013] Optionally, the molar ratio of template molecule, functional monomer and crosslinking agent is 1:(2~8):(5~40).

[0014] Optionally, the functional monomer is at least one selected from methacrylic acid, 4-vinylpyridine, 2-vinylpyridine, itaconic acid, acrylamide, 2-hydroxyethyl methacrylate, methyl methacrylate, acrylic acid, and methyl acrylate.

[0015] All of the above-mentioned functional monomers are compounds containing double bonds.

[0016] Preferably, the functional monomers are methacrylic acid and acrylamide.

[0017] More preferably, the molar ratio of methacrylic acid to acrylamide in the functional monomer is 1:(0.5~2.5).

[0018] More preferably, the molar ratio of methacrylic acid to acrylamide in the functional monomer is 1:2.

[0019] Optionally, the pore-forming agent is any one of methanol, ethanol, acetonitrile, and acetone.

[0020] Optionally, the crosslinking agent is at least one of glycidyl methacrylate, ethylene glycol diglycidyl methacrylate, N,N-methylenebisacrylamide, and ethylene glycol dimethacrylate.

[0021] Preferably, the crosslinking agent is ethylene glycol dimethacrylate.

[0022] More preferably, the molar ratio of template molecule to crosslinking agent is 1:20.

[0023] Optionally, the initiator is any one of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovalerate, 4,4-azobis(4-cyanopentanoic acid), benzoyl peroxide, potassium persulfate, and ammonium persulfate.

[0024] Optionally, the reaction temperature of the prepolymerization reaction is 4~10℃, and the reaction time of the prepolymerization reaction is 2~12h.

[0025] Optionally, the polymerization reaction temperature is 50~80℃, and the polymerization reaction time is 2~24h.

[0026] Optionally, the polymerization reaction is carried out under a protective atmosphere of nitrogen or argon, with a stirring speed of 300-600 rpm.

[0027] Optionally, template molecules in the polymerization product are removed by elution with a template remover, and the polymerization product is vacuum dried at a temperature of 60~100℃ for 6~14h.

[0028] Optionally, the template removal agent is a mixed solution of acetic acid and methanol, wherein the volume ratio of acetic acid to methanol is 1:(1~9).

[0029] The second objective of this invention is to provide a molecularly imprinted polymer material obtained by the above-mentioned method for preparing a molecularly imprinted polymer material that selectively adsorbs metalaxyl.

[0030] A third objective of this invention is to provide the application of the aforementioned molecularly imprinted polymer materials in the identification and detection of phenylamide drugs.

[0031] Optionally, the phenylamide class of drugs includes at least one of metalaxyl, benzalkonium chloride, furazolidone, or oxazolidone.

[0032] The beneficial effects of this invention are:

[0033] (1) The preparation method of the present invention is simple to operate and low in cost. The resulting molecularly imprinted polymer has uniform particle size distribution, high adsorption capacity, fast mass transfer rate, strong specificity, good stability and reusability. The imprinting factor of the molecularly imprinted polymer material prepared by the present invention is greater than 5.5 and the equilibrium adsorption capacity for metalaxyl is 44.2 mg / g.

[0034] (2) This invention uses metalaxyl as a virtual template and methacrylic acid and acrylamide as binary functional monomers. It utilizes the electrostatic interactions and hydrogen bonds between the template molecules and the binary functional monomers, and simultaneously, under the action of a crosslinking agent, to generate a polymer with a three-dimensional network structure. After eluting the template molecules, holes are exposed that can both match the spatial size of metalaxyl and interact with it, thus achieving the construction of a molecularly imprinted polymer material that selectively binds to metalaxyl.

[0035] (3) The molecularly imprinted polymer material prepared by the present invention has high adsorption capacity and specificity for phenylamide drugs such as metalaxyl, benzalkonium chloride, oxazolium chloride and furazolium chloride, with imprinting factors greater than 5.5. It can be used for the selective separation and enrichment of metalaxyl and its metabolite metalaxyl acid, as well as its homologues benzalkonium chloride, oxazolium chloride and furazolium chloride in environmental water bodies. Attached Figure Description

[0036] Figure 1 These are the adsorption performance test results of MIPs prepared with different monomers according to the present invention;

[0037] Figure 2 The adsorption performance test results are those of the MIP prepared by the binary functional monomer used in Example 3 of this invention.

[0038] Figure 3 These are the adsorption performance test results of polymers prepared with different molar ratios of template molecules and crosslinking agents in Example 4 of this invention;

[0039] Figure 4 These are the selective adsorption test results of MIP prepared in Example 4 and NIP prepared in Comparative Example 4 in water.

[0040] Figure 5 These are scanning electron microscope images of the MIP prepared in Example 4 and the NIP prepared in Comparative Example 4 at a magnification of 80k.

[0041] Figure 6 These are the infrared spectra of the MIP prepared in Example 4 and the NIP prepared in Comparative Example 4 of this invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0043] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not limited to those elements and may also include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0044] "Optional" or "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event will occur and the possibility that the event will not occur.

[0045] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of occurrences) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0046] The terms "one embodiment," "some embodiments," "exemplary," "specific example," or "some examples," etc., used in this invention refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this document, the illustrative expressions of the above terms are not necessarily directed at the same embodiment or example.

[0047] The numerical range described in this invention includes not only the point values ​​listed in the embodiments, but also any point values ​​not listed within the numerical range described in this invention. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0048] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the field.

[0049] This embodiment provides a method for preparing a molecularly imprinted polymer material that selectively adsorbs metalaxyl, specifically including the following steps:

[0050] S1. The template molecule oxadiazon is mixed with a porogen and a functional monomer to carry out a prepolymerization reaction to obtain a prepolymer product;

[0051] S2. Add a crosslinking agent and an initiator to the prepolymer product, and carry out a polymerization reaction under a protective atmosphere to obtain the polymer product;

[0052] S3. Use a template remover to elute the polymerization product, remove the template molecules in the polymerization product, and obtain a molecularly imprinted polymer material that selectively adsorbs metalaxyl.

[0053] The molecularly imprinted polymer material prepared in this embodiment is a polymer material synthesized using molecular imprinting technology that selectively recognizes and adsorbs specific template molecules and their structural analogs. During its preparation, the template molecule and functional monomer form multiple binding sites and are memorized. When the template molecule is removed, the polymer forms cavities with multiple binding sites that match the spatial configuration of the template molecule, thereby enabling it to specifically recognize the template molecule and its structural analogs.

[0054] In this embodiment, the template molecule is at least one of metalaxyl, benzalkonium chloride, oxazolium chloride, and furazolidone.

[0055] In this embodiment, the molar ratio of template molecule, functional monomer and crosslinking agent is 1:(2~8):(5~40).

[0056] In some specific embodiments, the functional monomer is at least one selected from methacrylic acid (MAA), 4-vinylpyridine (4-VP), 2-vinylpyridine (2-VP), itaconic acid (ITA), acrylamide (AM), 2-hydroxyethyl methacrylate (HEMA), methyl methacrylate, acrylic acid, and methyl acrylate.

[0057] In one specific implementation, the functional monomers are methacrylic acid and acrylamide.

[0058] In one specific embodiment, the molar ratio of methacrylic acid to acrylamide is 1:(0.5~2.5). As an example, the molar ratio of methacrylic acid to acrylamide can be 1:0.5, 1:0.75, 1:1, 1:1.25, 1:1.5, 1:1.75, 1:2, 1:2.25, or 1:2.5, as long as the molar ratio of methacrylic acid to acrylamide is within this range.

[0059] In one specific embodiment, the molar ratio of methacrylic acid to acrylamide in the functional monomer is 1:2. When the molar ratio of methacrylic acid to acrylamide is 1:2, the prepared molecularly imprinted polymer material has good adsorption performance and selectivity.

[0060] In some specific embodiments, the pore-forming agent is any one of methanol, ethanol, acetonitrile, and acetone.

[0061] In one specific embodiment, the pore-forming agent is methanol.

[0062] In some specific embodiments, the crosslinking agent is at least one of glycidyl methacrylate, ethylene glycol diglycidyl methacrylate, N,N-methylenebisacrylamide, and ethylene glycol dimethacrylate.

[0063] In one specific embodiment, the crosslinking agent is ethylene glycol dimethacrylate.

[0064] In one specific embodiment, the molar ratio of template molecules to crosslinking agents is 1:20. When the molar ratio of template molecules to crosslinking agents is 1:20, the adsorption performance and selectivity of the prepared molecularly imprinted polymer material are further improved.

[0065] In some specific embodiments, the initiator is any one of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovalerate, 4,4-azobis(4-cyanopentanoic acid), benzoyl peroxide, potassium persulfate, and ammonium persulfate.

[0066] In some specific embodiments, the metalaxyl solution prepared in step S1 is subjected to ultrasonic treatment at room temperature for 5-15 minutes, as an example. The ultrasonic treatment time can be 5 minutes, 7 minutes, 8 minutes, 10 minutes, 12 minutes, 13 minutes, or 15 minutes, as long as the ultrasonic treatment time is within this range.

[0067] In some specific embodiments, in step S1, to ensure that the template molecules and functional monomers dissolve more fully in the porogen, the mixture can be stirred during the sonication process until all template molecules are dissolved. Furthermore, this embodiment does not further limit the power of the sonication, the stirring speed, or the stirring time, as long as the template molecules and functional monomers are completely dissolved.

[0068] In some specific embodiments, the temperature of the prepolymerization reaction in step S1 is 4~10°C. As an example, the temperature of the prepolymerization reaction can be 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, or 10°C.

[0069] In some specific implementations, the prepolymerization reaction time in step S1 is 2 to 12 hours. As an example, the prepolymerization reaction time can be 2 hours, 4 hours, 5 hours, 7 hours, 8 hours, 10 hours, or 12 hours, as long as the prepolymerization reaction time is within this range.

[0070] In some specific implementations, the polymerization reaction in step S2 needs to be carried out under a protective atmosphere. For example, the protective atmosphere may be nitrogen or argon.

[0071] In some specific embodiments, the polymerization temperature in step S2 is 50~80°C. As an example, the polymerization temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C, as long as the polymerization temperature is within this range.

[0072] In some specific implementations, the polymerization reaction time in step S2 is 2 to 24 hours. As an example, the polymerization reaction time can be 2 hours, 4 hours, 5 hours, 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, or 24 hours, as long as the polymerization reaction time is within this range.

[0073] In some specific embodiments, the polymerization reaction in step S2 is carried out under stirring, with a stirring speed of 300-600 rpm. For example, the stirring speed can be 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, or 600 rpm, as long as the stirring speed falls within this range. This embodiment does not impose additional limitations on the stirring speed and time of the polymerization reaction, as long as the crosslinking agent and the prepolymer product react completely under the action of the initiator.

[0074] In some specific embodiments, after using a template remover to remove template molecules from the polymer product in step S3, vacuum drying is required to obtain a molecularly imprinted polymer material.

[0075] In some specific embodiments, the vacuum drying temperature in step S3 is 60~100℃. As an example, the vacuum drying temperature can be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃, as long as the vacuum drying temperature is within this range.

[0076] In some specific implementations, the vacuum drying time in step S3 is 6 to 14 hours. As an example, the drying time can be 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, or 14 hours, as long as the vacuum drying time is within this range.

[0077] In some specific embodiments, the template removal agent used in step S3 is a mixed solution of acetic acid and methanol, with a volume ratio of acetic acid to methanol of 1:(1~9). As an example, the volume ratio of acetic acid to methanol in the template removal agent can be 1:1, 1:2, 1:4, 1:5, 1:7, or 1:9, as long as the volume ratio of acetic acid to methanol in the template removal agent is within this range.

[0078] In another specific embodiment, the present invention provides a molecularly imprinted polymer material obtained by the above-described method for preparing a molecularly imprinted polymer material that selectively adsorbs metalaxyl.

[0079] In another specific embodiment, the molecularly imprinted polymer material prepared by the above method is used for selective identification and detection of phenylamide drugs in water.

[0080] The present invention will be further illustrated below through specific embodiments:

[0081] Example 1

[0082] In a 250 mL round-bottom flask, 120 mL of methanol and 1 mmol of the template molecule oxadiazon were added, sonicated for 10 minutes, and stirred at room temperature until completely dissolved. 4 mmol of the functional monomer methacrylic acid was added, and prepolymerization was carried out at 4 °C for 4 h. Then, 10 mmol of ethylene glycol dimethacrylate and 40 mg of azobisisobutyronitrile were added, sonicated, and the mixture was purged with nitrogen for protection. The polymerization reaction was carried out at 60 °C for 12 h with stirring. The resulting product was eluted with acetic acid / methanol (1:4, v / v) to remove the template molecule, and dried under vacuum at 80 °C for 12 h to obtain the molecularly imprinted polymer (MIP).

[0083] Example 2

[0084] The difference from Example 1 is that 4 mmol of methacrylic acid functional monomer was replaced with 4 mmol of acrylamide.

[0085] Example 3

[0086] The difference from Example 1 is that 4 mmol of the functional monomer of methacrylic acid was replaced with 2.67 mmol of methacrylic acid and 1.33 mmol of acrylamide.

[0087] Example 4

[0088] The difference from Example 3 is that the amount of ethylene glycol dimethacrylate was increased from 10 mmol to 20 mmol.

[0089] To further demonstrate the relevant properties of the molecularly imprinted polymer material prepared by this invention, several comparative examples and test cases are provided, as follows:

[0090] Comparative Example 1

[0091] The difference from Example 1 is that no template molecules are added, resulting in a non-molecularly imprinted polymer material (NIP).

[0092] Comparative Example 2

[0093] The difference from Example 2 is that no template molecules are added, resulting in a non-molecularly imprinted polymer material.

[0094] Comparative Example 3

[0095] The difference from Example 3 is that no template molecules are added, resulting in a non-molecularly imprinted polymer material.

[0096] Comparative Example 4

[0097] The difference from Example 4 is that no template molecules are added, resulting in a non-molecularly imprinted polymer material.

[0098] Test Example 1

[0099] The adsorption performance of the MIP or NIP materials obtained in Examples 1-4 and Comparative Examples 1-4 was tested. The specific experimental procedure was as follows: a 200 mg / L metalaxyl standard solution was prepared; 20 mg of the MIP and NIP prepared in Examples 1-4 and Comparative Examples 1-4 were weighed into 25 mL glass conical flasks, and 5 mL of the prepared standard solution was added. After shaking and adsorption for 4 h, the metalaxyl content in the supernatant was determined by high-performance liquid chromatography (HPLC), and the adsorption capacity and imprinting factor of the polymer material (MIP or NIP) for metalaxyl were calculated. Adsorption capacity ( Q e The formulas for calculating the imprint factor (IF) are as follows:

[0100]

[0101]

[0102] in Q e (mg / g) is the adsorption capacity of the polymer material (MIP or NIP); C 0 (mg / L) and C e (mg / L) represent the initial and final concentrations of metalaxyl, respectively; W (g) is the mass of the polymer material (MIP or NIP); and V (mL) is the solvent volume.

[0103] The results are shown in Table 1:

[0104] Table 1. Adsorption capacity and imprinting factor of the adsorbent materials in Examples 1-4 and Comparative Examples 1-4

[0105]

[0106] *Imprinting factor = MIP adsorption amount / NIP adsorption amount.

[0107] As shown in Table 1, the molecularly imprinted polymer material prepared in Example 1 has a high adsorption capacity, but its imprinting factor is low and its selectivity is poor. In contrast, the molecularly imprinted polymer material prepared in Example 4 has a higher adsorption capacity and stronger selectivity, enabling it to more efficiently identify and adsorb target molecules. Therefore, tests 5-7 of this invention use Example 4 and Comparative Example 4 as the test objects.

[0108] Test Example 2

[0109] This test case applies the MIP obtained in Example 4 to a real-world sample, as detailed below:

[0110] 100 mL of pond water was filtered through a 0.45 μm glass fiber membrane, and 100 µL of a mixed standard solution of metalaxyl and metalaxyl-methyl acid (concentration 10 ng / mL) was added and shaken to mix. 100 mg of the MIP material prepared in Example 4 was added, and the mixture was shaken for 30 minutes for adsorption. The mixture was then centrifuged at 5000 rpm for 5 minutes to remove the supernatant. The MIP material was washed with deionized water, and then 3 mL of 1% formic acid acetonitrile (v / v) was added. The mixture was vortexed for 10 minutes to elute metalaxyl and metalaxyl-methyl acid. The eluent was dried under nitrogen, reconstituted with 1 mL of 50% acetonitrile-water, and analyzed by LC-MS / MS. The results are shown in Table 2.

[0111] Table 2 Results of spiked recovery tests of metalaxyl and metalaxyl acid in pond water samples (n=5)

[0112]

[0113] As shown in Table 2, the recoveries of metalaxyl and metalaxyl acid in the three pond water samples were 85.2-96.8% and 84.6-93.1%, respectively, with relative standard deviations of less than 6.8%. This preliminarily indicates that the test results are accurate and reliable, demonstrating that the molecularly imprinted polymer material obtained by this invention has good stability and practical application effect.

[0114] Test Example 3

[0115] This test example examines the adsorption performance of MIPs prepared with different monomers. Compared to Examples 1 and 2, the only difference between the examples using the other four functional monomers and those using methacrylic acid and acrylamide as functional monomers is that the functional monomers are replaced with methacrylic acid (MAA), 4-vinylpyridine (4-VP), 2-vinylpyridine (2-VP), itaconic acid (ITA), acrylamide (AM), and 2-hydroxyethyl methacrylate (HEMA), respectively. Specific test results are as follows: Figure 1 As shown.

[0116] from Figure 1 As can be seen, the MIP prepared with methacrylic acid as the functional monomer has a relatively high adsorption capacity of 29.9 mg / g, but low specificity, with an imprinting factor of 1.32; the MIP prepared with acrylamide as the functional monomer has the strongest specificity, with an imprinting factor as high as 2.88, but a relatively low adsorption capacity of 12.9 mg / g. Taking all factors into consideration, methacrylic acid and acrylamide are the preferred binary functional monomers for molecularly imprinted polymers.

[0117] Test Example 4

[0118] This test example further tests the functional monomers used in Example 3. Using the molar amount of methacrylic acid as a reference, the adsorption performance is explored by varying the molar amount of acrylamide. The results are as follows: Figure 2 As shown.

[0119] from Figure 2 As can be seen, when the molar ratio of methacrylic acid and acrylamide is 1:2, the prepared MIP imprinting factor reaches 2.41 and the adsorption capacity is 15.4 mg / g, which shows the best adsorption capacity and selectivity.

[0120] Test Example 5

[0121] This test case further investigates the effect of the amount of crosslinking agent on the adsorption performance of MIP, based on Test Case 3. Specifically, it investigates the adsorption performance of polymers prepared in Example 4 with different molar ratios of the template molecule oxadiazon and the crosslinking agent ethylene glycol dimethacrylate. The results are as follows: Figure 3 As shown. From Figure 3 It can be seen that when the molar ratio of template molecule to crosslinking agent is 1:20, the adsorption capacity of the prepared MIP is 28.8 mg / g and the imprinting factor is 4.69, and its adsorption performance and specificity are both optimal.

[0122] Test Example 6

[0123] This test case investigated the specific adsorption performance of the polymer prepared in Example 4 in water. The results are as follows: Figure 4 As shown.

[0124] from Figure 4 As can be seen, MIP exhibits good class-specific adsorption performance for phenylamide drugs. At an initial concentration of 400 mg / L, the adsorption capacities of MIP for metalaxyl, benalaxyl, furaxyl, and oxadixyl were 44.2 mg / g, 40.3 mg / g, 41.3 mg / g, and 53.4 mg / g, respectively, with imprinting factors (IF) all greater than 5.5, demonstrating strong specificity. This is because metalaxyl, benalaxyl, and furaxyl are highly similar to the template molecule oxadixyl in molecular size and spatial structure. Therefore, the molecularly imprinted polymer material obtained in this invention has high selectivity for phenylamide drugs such as metalaxyl and can be used for the selective recognition and detection of phenylamide drugs.

[0125] Test Example 7

[0126] This test case performs microscopic characterization on the MIP obtained in Example 4 and the NIP obtained in Comparative Example 4. The electron micrographs of the two are shown below. Figure 5 As shown.

[0127] from Figure 5As can be seen, the MIPs obtained in Example 4 and the NIPs obtained in Comparative Example 4 have similar morphological characteristics, both exhibiting a rough-surfaced nanosphere morphology. The MIP particles have a larger diameter than the NIPs, and the MIPs appear as dispersed individual microspheres, while the NIP particles have a smaller diameter and show significant aggregation. The inventors speculate that the difference in particle size between MIPs and NIPs is due to the space occupied by the interaction between the template molecules and functional monomers during the imprinting process altering the internal structure of the polymer material. The MIP microspheres obtained in Example 4 have a higher specific surface area, which can effectively improve the adsorption capacity and mass transfer rate of the imprinted material.

[0128] Test Example 8

[0129] This test example performs infrared spectral characterization on the MIP obtained in Example 4 and the NIP obtained in Comparative Example 4. The results are as follows: Figure 6 As shown.

[0130] from Figure 6 As can be seen, the characteristic absorption peaks of MIP and NIP are basically the same, around 3655 cm⁻¹. -1 The absorption at 1730 cm⁻¹ is attributed to the stretching vibration of the NH group of the amide group in the functional monomer AM; -1 The absorption at this point is attributed to the C=O stretching vibration, which is a characteristic functional group of MAA, AM, and EGDMA; at 1258 cm⁻¹ -1 and 1157cm -1 The absorption at this location is attributed to the symmetric and asymmetric stretching vibrations of COC, which are also characteristic functional groups of EGDMA; at 1258 cm⁻¹ -1 The absorption at this point is attributed to the CO stretching vibration, a characteristic functional group of the MAA; at 1638 cm⁻¹ -1 The absorption at this point is attributed to the symmetric stretching vibration of C=C. The weak absorption at this point indicates that the C=C reaction in the polymer is essentially complete. These results show that MAA, AM, and EGDMA have all been successfully polymerized in both MIP and NIP, and there is no significant difference in the vibrational peaks of the functional groups. Furthermore, MIP shows a significant absorption at 3426 cm⁻¹. -1 There is an OH stretching vibration at 2987 cm. -1 and 2954cm -1 The CH asymmetric stretching vibrations of saturated hydroxyl and aldehyde groups appear at 1730 cm⁻¹. -1 The C=O stretching vibration at the point indicates that the template molecule in the MIP has been eluted, and the characteristic peaks of COC, CO, and C=O still exist after elution, further confirming that the MIP has formed a stable imprinted framework and has imprinted cavities that can selectively recognize metalaxyl and its homologues. That is, the molecularly imprinted polymer material obtained by this invention has good specificity and can accurately identify and adsorb the target and its structurally similar homologues.

[0131] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for producing a molecularly imprinted polymer material selectively adsorbing metalaxyl, characterized by, The method comprises the following steps: mixing the template molecule with a pore-forming agent to obtain a template molecule solution, and mixing the template molecule solution with a functional monomer to perform a prepolymerization reaction to obtain a prepolymerization product; adding a crosslinking agent and an initiator to the prepolymerization product, and performing a polymerization reaction under a protective atmosphere to obtain a polymerization product; eluting the polymerization product using a template removal agent to remove the template molecule in the polymerization product, and obtaining a molecularly imprinted polymer material capable of selectively adsorbing metalaxyl; the molar ratio of the template molecule, the functional monomer and the crosslinking agent is 1:(2-8):(5-40); the functional monomer comprises methacrylic acid and acrylamide, and the molar ratio of the methacrylic acid to the acrylamide is 1:(0.5-2.5).

2. The method for preparing a molecularly imprinted polymer material selectively adsorbing metalaxyl according to claim 1, characterized in that, the template molecule is at least one of metalaxyl, benalaxyl, oxadixyl and ofurace.

3. The method for preparing a molecularly imprinted polymer material selectively adsorbing metalaxyl according to claim 1, characterized in that, the pore-forming agent comprises at least one of methanol, ethanol, acetonitrile and acetone; The crosslinking agent includes at least one of glycidyl methacrylate, N,N methylenebisacrylamide, ethylene glycol dimethacrylate the initiator comprises at least one of azobisisobutyronitrile, azobisisoheptyl nitrile, azobisisopentyl nitrile, 4,4-azobis(4-cyanopentanoic acid), benzoyl peroxide, potassium persulfate and ammonium persulfate.

4. The method of claim 1, wherein the method is characterized by the steps of: the reaction temperature of the prepolymerization reaction is 4-10°C, and the reaction time of the prepolymerization reaction is 2-12h; the reaction temperature of the polymerization reaction is 50-80°C, and the reaction time of the polymerization reaction is 2-24h.

5. The method for preparing a molecularly imprinted polymer material selectively adsorbing metalaxyl according to any one of claims 1 to 4, characterized in that, the reaction conditions of the polymerization reaction further comprise stirring under a protective atmosphere, the protective atmosphere is nitrogen or argon, and the stirring speed is 300-600rpm.

6. The method for preparing a molecularly imprinted polymer material selectively adsorbing metalaxyl according to claim 1, characterized in that, after eluting and removing the template molecule in the polymerization product using the template removal agent, the polymerization product needs to be vacuum dried at a temperature of 60-100°C for 6-14h; the template removal agent is a mixed solution of acetic acid and methanol, and the volume ratio of acetic acid to methanol is 1:(1-9).

7. A molecularly imprinted polymer material selectively adsorbing metalaxyl, characterized in that the molecularly imprinted polymer material is obtained by the preparation method in any one of claims 1-6.

8. A method for detecting a phenylamide drug in a water body, characterized in that, the molecularly imprinted polymer material obtained by the preparation method in any one of claims 1-6 or the molecularly imprinted polymer material capable of selectively adsorbing metalaxyl in claim 7 is used for selective identification and detection of phenylamide drugs.

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