Method for rapidly detecting carbamate pesticides in fruits and products thereof by magnetic solid-phase extraction / enzyme inhibitor method, adsorbent and preparation method thereof

Abstract

The invention discloses a method for rapidly detecting carbamate pesticides in fruits and products thereof by a magnetic solid-phase extraction / enzyme inhibitor method, an adsorbent and a preparation method thereof, and belongs to the technical field of pesticide detection. The method for detecting the carbamate pesticides in the fruits and the products thereof comprises the following steps: S01, sampling; s02, adding an extracting solution for extraction; s03, adding an adsorbent to carry out pretreatment adsorption; s04, loading a sample, and detecting; wherein an adsorbent in the pretreatment process is Fe3O4 magnetic mesoporous silica nanoparticles modified by functional modification oleic acid. When the functionalized OA-Fe3O4-coated MSN NPs / enzyme inhibitor method is used for rapidly detecting carbamate pesticides in fruits and products thereof, the problem of organic solvent removal in the pretreatment process is solved, and rapid detection operation is further realized.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide detection, and particularly relates to a method for rapidly detecting carbamate pesticides in fruits and their products by magnetic solid phase extraction / enzyme inhibitor method, an adsorbent thereof, and a preparation method thereof. Background Art

[0002] At present, the pre-treatment process of rapid detection of pesticide residues involves cumbersome steps such as removal and concentration of organic solvents.

[0003] Magnetic solid-phase extraction is a solid-phase extraction technology that uses magnetic nanoparticles as adsorbents and separates the magnetic nanoparticles from the matrix through an external magnetic field. It is a new type of sample pretreatment technology and has been widely used in separating and enriching trace targets in complex matrices. Summary of the invention

[0004] In order to solve the problem of complicated steps such as organic solvent removal and concentration in the pre-treatment process of pesticide residue rapid detection, the present invention carried out a novel method based on oleic acid-modified Fe 3 O 4 Magnetic nanoparticles, magnetic mesoporous adsorption materials (OA-Fe 3 O 4 @MSN)’s functional modification and application research.

[0005] The first aspect of the present invention is to disclose a method for rapid detection of carbamate pesticides in fruits and their products by magnetic solid phase extraction / enzyme inhibitor method, comprising the following steps:

[0006] S01, sampling;

[0007] S02, adding extraction solution for extraction;

[0008] S03, adding adsorbent for pre-treatment adsorption;

[0009] S04, loading samples and testing;

[0010] Among them, the adsorbent in the pretreatment process is functionalized oleic acid-modified Fe 3 O 4 Magnetic mesoporous silica nanoparticles.

[0011] In some embodiments of the present invention, the functional modification of the adsorbent is grafting of -Ph groups or -CN groups.

[0012] In some embodiments of the present invention, the oleic acid-modified Fe 3 O 4 The magnetic mesoporous silica nanoparticles are embedded structures, and the preparation process includes the following steps: oleic acid-modified Fe 3O 4 The magnetic nanoparticles were first formed into an oil-in-water microemulsion, and then the oleic acid-modified Fe 3 O 4 Magnetic mesoporous silica nanoparticles.

[0013] In some embodiments of the present invention, the oleic acid-modified Fe 3 O 4 The magnetic nanoparticles are thermal decomposition products of iron oleate complex.

[0014] In some embodiments of the present invention, the steps include: weighing a sample, adding an extract, shaking vigorously and then standing, absorbing the supernatant, adding an adsorbent, vortexing and mixing, adsorbing by a magnet, discarding the supernatant, quantifying the elution solvent, and determining by an enzyme inhibitor method;

[0015] Preferably, the elution solvent is a mixed solution of an organic solvent, a phosphate buffer and a surfactant; further preferably, the elution solvent is a mixed solution of methanol, a phosphate buffer and Tween 80.

[0016] Preferably, the enzyme inhibitor method comprises the following steps: adding a test solution, acetylcholinesterase and a color developer, water bathing, adding phosphate buffer to the reference, adjusting the zero value as a standard solution, adding a substrate to the test solution, measuring the absorbance difference with an ultraviolet spectrophotometer, and calculating the concentration of the test substance.

[0017] In some embodiments of the present invention, the extracting solution is acetonitrile, sodium citrate, and disodium hydrogen citrate; a ceramic homogenizer is also used in the extraction.

[0018] In some embodiments of the present invention, 0.5-5 mg of adsorbent is added per ml of extract.

[0019] The second aspect of the present invention is to disclose an adsorbent, comprising the functionalized oleic acid-modified Fe 3 O 4 Magnetic mesoporous silica nanoparticles.

[0020] The third aspect of the present invention is to disclose a method for preparing the adsorbent according to the second aspect, comprising the following steps:

[0021] S11, Preparation of Oleic Acid-Modified Fe by High-Temperature Thermal Decomposition 3 O 4 Magnetic nanoparticles;

[0022] S12, Preparation of Oleic Acid-Modified Fe by Sol-Gel Method 3 O 4 Magnetic mesoporous silica nanoparticles;

[0023] S13, adding silane coupling agent for functional modification.

[0024] In some embodiments of the present invention, the oleic acid-modified Fe obtained in S11 3 O 4 The size of magnetic nanoparticles is 6-17nm;

[0025] Oleic acid-modified Fe obtained in S12 3 O 4 The size of magnetic mesoporous silica nanoparticles is 200-250nm;

[0026] Functionally modified oleic acid-modified Fe obtained in S13 3 O 4 The pores of magnetic mesoporous silica nanoparticles are 2-3nm and the particle size is 200-300nm.

[0027] Beneficial effects:

[0028] In the preparation of the adsorbent of the present invention, oleic acid-modified Fe 3 O 4 The advantages of magnetic nanoparticles are that the reaction steps are simple and large-scale synthesis is convenient; the prepared nanoparticles have a relatively neat crystal morphology, and the particle size and morphology are easy to control; the sol-gel method is used to prepare oleic acid-modified Fe 3 O 4 Magnetic mesoporous silica nanoparticles have the advantage that SiO 2 Can effectively prevent Fe 3 O 4 Leakage and aggregation, keep Fe 3 O 4 While the magnetism and particles are stable, the impact on the detection enzyme is reduced; secondly, SiO 2 Contains a large number of highly reactive functional groups (silanol groups), which can be modified specifically on the surface according to the structure of the analyte; secondly, mesoporous SiO 2 The pores can provide a large number of reaction sites and can quickly adsorb the substance to be tested. The addition of silane coupling agent for functional modification is to enhance the intermolecular force between magnetic nanoparticles and the target, thereby selectively adsorbing the target.

[0029] At present, the purification adsorption particles used in the solid phase extraction process of pesticide residues mainly include PSA ((N-propylethylenediamine)), C18 (octadecyl bonded silica matrix solid phase extraction material) and graphitized carbon black. PSA and graphitized carbon black are mainly used to remove carotenoids and chlorophyll in the matrix, and PSA and C18 are mainly used to remove fats, waxes and sugars in the matrix. The functionalized oleic acid-modified Fe3 O 4 Magnetic mesoporous silica nanoparticles are magnetic solid phase extraction materials used in the rapid detection of pesticide residues. They can directly adsorb and disperse the target onto the surface of the magnetic adsorbent. Under the action of an external magnetic field, the target migrates with the adsorbent and is finally eluted with a suitable solvent to separate it from the sample matrix. This method is time-saving and fast, and can solve problems such as organic solvent removal without the need for centrifugation and other steps.

[0030] Functionalized OA-Fe of the present invention 3 O 4 @MSN The NPs / enzyme inhibitor method solves the problem of removing organic solvents during the pretreatment process when rapidly detecting carbamate pesticides in fruits and their products, and further realizes rapid detection operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The steps of preparing the iron oleate complex according to Example 1;

[0032] Figure 2 Preparation of oleic acid-modified Fe 3 O 4 Steps of magnetic nanoparticles;

[0033] Figure 3 Preparation of oleic acid-modified Fe 3 O 4 Steps for magnetic mesoporous silica nanoparticles;

[0034] Figure 4 Example 1 Oleic acid modified Fe 3 O 4 Functional modification steps of magnetic mesoporous silica nanoparticles;

[0035] Figure 5 The oleic acid-modified Fe 3 O 4 TEM images and particle size distribution of magnetic nanoparticles;

[0036] Figure 6 The oleic acid-modified Fe 3 O 4 TEM images and particle size distribution of magnetic mesoporous silica nanoparticles after functional modification;

[0037] Figure 7 The oleic acid-modified Fe 3 O 4 Functionalization modification steps and 13C-NMR spectra of magnetic mesoporous silica nanoparticles;

[0038] Figure 8The oleic acid-modified Fe 3 O 4 Functional modification of magnetic mesoporous silica nanoparticles 2 Adsorption spectrum;

[0039] Fig. 9 The oleic acid-modified Fe 3 O 4 XRD spectrum of magnetic mesoporous silica nanoparticles after functional modification;

[0040] Fig.10 The oleic acid-modified Fe 3 O 4 DLS spectra of magnetic mesoporous silica nanoparticles after functional modification;

[0041] Fig.11 The adsorption effect of the adsorbent material of Example 1 on carbamate pesticides;

[0042] Fig.12 The extraction effect of the adsorption material of Example 1 on carbamate pesticides in pears;

[0043] Fig.13 The effect of the adsorption material of Example 1 combined with UPLC / MS / MS in detecting carbamate pesticides in fruits and their products;

[0044] Fig.14 OA-Fe of Example 1 3 O 4 @MSN-CN NPs / enzyme inhibitor method for rapid detection of carbamate pesticides in fruits and their products;

[0045] Fig.15 OA-Fe of Example 1 3 O 4 @MSN-CN Standard curve for rapid detection of pesticide residues in pears by NPs / enzyme inhibitor method. DETAILED DESCRIPTION

[0046] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0047] Unless otherwise specified, the examples and comparative examples are parallel tests with the same parameters such as components, component contents, preparation steps, preparation parameters, and dimensions.

[0048] Example 1

[0049] Preparation of adsorbent:

[0050] (1) Oleic acid-modified Fe 3 O 4 Preparation of magnetic nanoparticles (high temperature thermal decomposition method)

[0051] like Figure 1 As shown, ferric chloride and sodium oleate are used as raw materials, reacted in a solvent system of ethanol, distilled water and n-hexane at 70° C. to obtain an oleic acid iron complex.

[0052] like Figure 2 As shown, the oleic acid iron complex was thermally decomposed at high temperature in the 1-octadecene solvent system to obtain monodispersed OA-Fe 3 O 4 NPs, namely, oleic acid-modified Fe 3 O 4 Magnetic nanoparticles.

[0053] Specifically, 10.8 g of ferric chloride (FeCl 3 6H2O, 40mmol, Aldrich, 98%) and 36.5g sodium oleate ( 120mmol, TCI, 95%) was dissolved in a mixed solvent consisting of 80ml ethanol, 60ml distilled water and 140ml hexane. The resulting solution was heated to 70°C and kept at this temperature for 4 hours. When the reaction was completed, the upper organic layer containing the oleic acid iron complex was washed three times with 30ml distilled water in a separating funnel. After washing, the hexane was evaporated to form the oleic acid iron complex in the form of a waxy solid.

[0054] 3.6 g (4 mmol) of the iron oleate complex synthesized as described above and 0.57 g of oleic acid (2 mmol, 90%) were dissolved in 20 g of 1-octadecene. The reaction mixture (can be ultrasonicated for 3-5 min, the homogeneity of the synthesized sample is better after mixing) was heated to 320°C at a heating rate of 0.6°C / s. The reaction time was adjusted to control the size of the IOPS, and heating for about 10, 30, and 45 minutes was performed to obtain iron oxide nanoparticles with 6, 13, and 17 nm.

[0055] The obtained solution containing nanocrystals was then cooled to room temperature, and 500 ml of ethanol was added to the solution to precipitate the nanocrystals. The nanocrystals were obtained by centrifugal separation.

[0056] (2) Oleic acid-modified Fe 3 O 4 Preparation of magnetic mesoporous silica nanoparticles (sol-gel method)

[0057] like Figure 3 As shown, the oleic acid-modified Fe 3 O 4 The magnetic nanoparticles were uniformly dispersed in chloroform, and a hexadecyltrimethylammonium bromide (CTAB) aqueous solution was added. The chloroform was evaporated, and distilled water was added. The mixture was stirred at 40°C for 2 h. Concentrated ammonia, tetraethyl orthosilicate (TEOS) and ethyl acetate were added. The mixture was stirred at 40°C for 6 h. The obtained initial product was repeatedly washed with methanol and water, filtered, and an ethanolic ammonium nitrate solution was added. The mixture was refluxed for 6 h 3 times to remove the CTAB template. The mixture was dialyzed for 72 h and dried at 50°C to obtain OA-Fe 3 O 4 @MSNNPs, i.e., oleic acid-modified Fe 3 O 4 Magnetic mesoporous silica nanoparticles.

[0058] Specifically, 7.5 mg of the obtained oleic acid-modified Fe 3 O 4 The magnetic nanoparticles were dispersed in 1 mL of chloroform, and 10 mL of an aqueous solution containing 0.1 g of CTAB was added and stirred vigorously. The chloroform was evaporated at 65 °C to obtain CTAB-Fe 3 O 4 Dispersion. Then, 90 ml of distilled water was added. Stir rapidly at 40°C for 2 h, then 3 mL of ammonia solution (25%), 0.5 mL of tetraethyl orthosilicate and 5 mL of ethyl acetate were added in sequence, stirred rapidly for 1 min, and then kept at 40°C for 6 h. The synthesized product was centrifuged, washed with distilled water and ethanol multiple times. Further purification was carried out by ion exchange to remove structure-directed CTAB. The synthesized product was dispersed in an ethanol solution of ammonium nitrate (60 mL, 10 mg / mL). The mixture was refluxed for 6 h, collected by centrifugation, and washed repeatedly with ethanol. Finally, the resulting product was dried under vacuum to obtain a brown-yellow powder.

[0059] (3) Oleic acid-modified Fe 3 O 4 Functional modification of magnetic mesoporous silica nanoparticles

[0060] like Figure 4 As shown, the oleic acid-modified Fe 3 O 4 Add ethanol solution to the magnetic mesoporous silica nanoparticles, add silane coupling agent, stir at 80 ° C for 6 h, centrifuge, wash with ethanol three times, and dry to obtain the grafted OA-Fe 3 O 4 @MSN NPs, i.e., oleic acid-modified Fe after grafting modification 3 O 4 Magnetic mesoporous silica nanoparticles.

[0061] In step (1), the effect of the thermal decomposition temperature on the particle size of the obtained particles is shown in Tables 1 and Figure 5 As shown. By selecting organic solvents (trioctylamine) with different boiling points and adjusting the temperature program, nanoparticles with particle sizes of 6nm, 13nm, 17nm and 35nm can be obtained. TEM shows that OA-Fe 3 O 4 The NPs have uniform particle size, which is consistent with the dynamic light scattering (DLS) test results, with a diameter of about 13 nm, and are the nanoparticles selected for this experiment.

[0062] Table 1 Effect of heating procedure on particle size

[0063]

[0064] In step (2), if Figure 6 As shown in Figure 2, TEM shows that the magnetic iron oxide particles are successfully encapsulated in OA-Fe 3 O 4 @MSNNps, the particle size is about 230nm. 3 O 4 @MSN Nps are superparamagnetic.

[0065] In step (3), if Figure 7 As shown in Figure 2, phenyltriethoxysilane and 4-(triethoxy)silyl butyronitrile contributed -Ph and -CN groups respectively in the synthesis reaction. The 13C-NMR spectrum showed that OA-Fe was successfully synthesized. 3 O 4 @MSN-Ph NPs and OAFe 3 O 4 @MSN-CN Nps. N 2 Adsorption spectrum ( Figure 8 ) shows that OA-Fe 3 O 4 @MSN NPs have a pore diameter of about 3 nm, and OA-Fe 3 O 4 @MSN-Ph NPs and OAFe 3 O 4 @MSN-CN The pore diameter of Nps is about 2.3nm. The pore diameter of mesoporous silica modified with functional groups is reduced. The XRD spectrum ( Fig. 9 ) also confirmed this. DLS spectrum ( Fig.10 ) shows that OA-Fe 3 O 4 @MSN-CNNPs and OAFe 3 O 4@MSN-Ph NPs have a particle size of about 250nm and 275nm.

[0066] Example 2

[0067] Adsorption performance of the prepared adsorbent in pretreatment

[0068] Weigh 5 g of sample (accurate to 0.01 g) into a 50 mL plastic centrifuge tube, add 10 mL of acetonitrile, 1 g of sodium citrate, 0.5 g of disodium hydrogen citrate and 1 ceramic homogenizer, cover the centrifuge tube, shake vigorously for 1 min and let stand for 3 min. Pipette a certain amount of supernatant into the centrifuge tube (add 2.5 mg of functionalized OA-Fe per ml of extract). 3 O 4 @MSN NPs), vortex mix for 1 min, adsorb on magnet, discard supernatant, quantify with organic solvent, pass through micro-membrane, and detect on UPLC / MS / MS machine.

[0069] like Fig.11 As shown, OA-Fe 3 O 4 @MSN-CN NPs have a stronger adsorption effect on carbamate pesticides, and the adsorption rates of the same magnetic adsorption material for different pesticides are not much different.

[0070] Example 3

[0071] The prepared adsorbent combined with enzyme inhibitor method for rapid detection of pesticide residues

[0072] The same operation steps as in Example 2 were followed. After the organic solvent extraction was completed, a certain amount of supernatant was pipetted into a centrifuge tube (2.5 mg of functionalized OA-Fe was added per ml of extract). 3 O 4 @MSN NPs), vortex mix for 1 min, magnet adsorb, and discard the supernatant. OA-Fe after adsorption of pesticides 3 O 4 @MSN NPs were added with a pre-prepared solvent, and the pesticide concentration was determined by the enzyme inhibitor method after all the pesticides in the pores were dissolved and released. The solvent was a mixed solution of 5.4 mL phosphate buffer (pH = 8), 0.6 mL methanol and 0.22 g T80 (Tween 80).

[0073] 1. Determination of acetylcholinesterase activity: Take two test tubes A and B, add 3 ml of 0.1 mol / L pH = 8 sodium bicarbonate solution, 50 μL of acetylcholinesterase and 50 μL of DTNB respectively, place in a 37±1℃ water bath for 15 minutes, then add 50 μL of 0.1 mol / L pH = 8 sodium bicarbonate solution to test tube A as the standard solution for zero adjustment; add 50 μL of ATCI to test tube B, mix well and immediately pour into a glass colorimetric cup for colorimetry, and record the ΔA0 value before and after 3 minutes.

[0074] 2. Determination of the inhibition of acetylcholinesterase activity by organic solvents and surfactants: Take two test tubes C and D, add 3 mL of the prepared solution, 50 μL of acetylcholinesterase and 50 μL of DTNB to each test tube, place in a 37±1℃ water bath for 15 min, then add 50 μL of 0.1 mol / L pH=8 sodium bicarbonate solution to test tube C as the standard solution for zero adjustment; add 50 μL of ATCI to test tube D, mix well and immediately pour into a glass colorimetric cup for colorimetry, and record the ΔAt value before and after 3 min.

[0075] 3. Determination of pesticide inhibition rate: Take two test tubes E and F, add 3 mL of pesticide solution, 50 μL of acetylcholinesterase and 50 μL of DTNB respectively, place in a 37±1℃ water bath for 15 min, add 50 μL of 0.1 mol / L pH=8 sodium bicarbonate solution to test tube E as the standard solution for zero adjustment; add 50 μL of ATCI to test tube F, mix well and immediately pour into a glass colorimetric cup for colorimetry, and record the ΔAp value before and after 3 minutes.

[0076] Pesticide inhibition rate / % = (ΔA0-ΔAp) / ΔA0*100%

[0077] Solution system rate / % = (ΔA0-ΔAt) / ΔA0*100%

[0078] The extraction effect of carbamate pesticides in pears, such as Fig.12 As shown. When the concentration of methomyl and carbaryl added was 0.01 mg / kg, the recovery rate was low and did not meet the detection requirements. When the concentration was higher, the recovery rate was higher. The recovery rates of carbofuran, carbaryl and carbosulfan were between 75% and 89%, which met the detection requirements.

[0079] like Fig.13 As shown in the figure, the combined UPLC / MS / MS is effective in detecting carbamate pesticides in fruits and their products. Fig.14 As shown, OA-Fe 3 O 4@MSN-CN NPs were used as adsorbents, and the solvent system of organic solvent + 5.4 mL phosphate buffer (pH = 8) surfactant was used, which was conducive to the release of pesticides from the mesopores. 0.6 mL methanol and 0.22 g T80 had the least inhibitory effect on AchE, and could promote the release and dissolution of more than 90% of the adsorbed pesticides. Fig.15 As shown, when the OA-Fe3O4@MSN-CN NPs / enzyme inhibitor method was used to detect pesticide residues in pears, the minimum detection concentrations of carbofuran, methomyl, carbaryl, and butyralid were 2.5 mg / kg, 25 mg / kg, 100 mg / kg, and 5 mg / kg, respectively.

[0080] The preferred specific implementation modes and embodiments of the present invention are described in detail above, but the present invention is not limited to the above implementation modes and embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the concept of the present invention.

Claims

1. A method for rapid detection of carbamate pesticides in fruits and their products by magnetic solid phase extraction / enzyme inhibitor method, characterized in that: The following steps are involved: S01, sampling; S02, adding extraction solution for extraction; S03, adding adsorbent for pre-treatment adsorption; S04, loading samples and testing; Among them, the adsorbent in the pretreatment process is functionalized oleic acid-modified Fe3O4 magnetic mesoporous silica nanoparticles.

2. The method for rapid detection of carbamate pesticides in fruits and their products according to claim 1, characterized in that: The functional modification of the adsorbent is grafting -Ph groups or -CN groups.

3. The method for rapid detection of carbamate pesticides in fruits and their products according to claim 1 or 2, characterized in that: The oleic acid modified Fe3O4 magnetic mesoporous silica nanoparticles are of an embedded structure, and the preparation process comprises the following steps: the oleic acid modified Fe3O4 magnetic nanoparticles are first formed into an oil-in-water microemulsion, and then the oleic acid modified Fe3O4 magnetic mesoporous silica nanoparticles are synthesized by a sol-gel method.

4. The method for rapid detection of carbamate pesticides in fruits and their products according to claim 3, characterized in that: The oleic acid-modified Fe3O4 magnetic nanoparticles are thermal decomposition products of oleic acid iron complexes.

5. The method for rapid detection of carbamate pesticides in fruits and their products according to claim 1 or 2, characterized in that: The method comprises the following steps: weighing a sample, adding an extracting solution, shaking vigorously and then standing, absorbing the supernatant, adding an adsorbent, vortexing and mixing, adsorbing by a magnet, discarding the supernatant, quantifying the elution solvent, and determining by an enzyme inhibitor method; Preferably, the elution solvent is a mixed solution of an organic solvent, a phosphate buffer and a surfactant; Preferably, the enzyme inhibitor method comprises the following steps: adding a test solution, acetylcholinesterase and a color developer, water bathing, adding phosphate buffer to the reference, adjusting the zero value as a standard solution, adding a substrate to the test solution, measuring the absorbance difference with an ultraviolet spectrophotometer, and calculating the concentration of the test substance.

6. The method for rapid detection of carbamate pesticides in fruits and their products according to claim 5, characterized in that: The extracting solution is acetonitrile, sodium citrate and disodium hydrogen citrate; a ceramic homogenizer is also used in the extraction.

7. The method for rapid detection of carbamate pesticides in fruits and their products according to claim 5 or 6, characterized in that: Add 0.5-5 mg of adsorbent per ml of extract.

8. An adsorbent, characterized in that The invention comprises the functionalized oleic acid-modified Fe3O4 magnetic mesoporous silica nanoparticles in the method for rapidly detecting carbamate pesticides in fruits and their products by magnetic solid phase extraction / enzyme inhibitor method according to any one of claims 1 to 4.

9. The method for preparing an adsorbent according to claim 8, characterized in that: The following steps are involved: S11, preparation of oleic acid-modified Fe3O4 magnetic nanoparticles by high temperature thermal decomposition method; S12, preparation of Fe3O4 magnetic mesoporous silica nanoparticles modified with oleic acid by sol-gel method; S13, adding silane coupling agent for functional modification.

10. The preparation method according to claim 9, characterized in that: The size of the oleic acid-modified Fe3O4 magnetic nanoparticles obtained in S11 was 6–17 nm; The size of the oleic acid-modified Fe3O4 magnetic mesoporous silica nanoparticles obtained in S12 was 200-250 nm; The functionally modified oleic acid-modified Fe3O4 magnetic mesoporous silica nanoparticles obtained in S13 have pores of 2-3 nm and a particle size of 200-300 nm.

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