Multifunctional magnetic adsorbent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of analysis and detection, and particularly relates to a multifunctional magnetic adsorbent and a preparation method and application thereof. According to the preparation method of the multifunctional magnetic adsorbent provided by the invention, the magnetic material, the adsorbent, the pH regulator and the derivative reagent are mixed and ground, and the self-assembly of the material is realized by adopting a one-pot grinding method, so that the multifunctional magnetic adsorbent is prepared. The multifunctional magnetic adsorbent integrates the functions of magnetism, adsorption, pH adjustment and derivation at the same time, when the material is used for sample pretreatment, a pH adjusting agent or a derivation reagent does not need to be additionally added, meanwhile, rapid liquid-solid separation can be achieved with the help of a magnet, centrifugation or filtration is not needed, and therefore operation steps can be effectively simplified, operation errors are reduced, and the operation efficiency is improved. Efficient derivatization and enrichment of a target analyte are achieved, and the method is suitable for high-sensitivity analysis and detection of complex matrix samples and particularly suitable for analysis of small molecular compounds.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis and detection, and specifically relates to a multifunctional magnetic adsorbent and a preparation method and application thereof. Background Art

[0002] In the field of analytical testing, chromatography technology (including liquid chromatography and gas chromatography) is a common means of qualitative and quantitative analysis of target analytes. When using chromatography technology to detect target analytes, for samples that cannot be directly sampled and tested, the samples need to be pre-treated before chromatographic analysis. The sample pretreatment process mainly includes two key steps: derivatization and extraction, which aims to improve the qualitative and quantitative detection capabilities of target analytes in complex matrices. However, the above sample pretreatment process often consumes a lot of time and manpower. Therefore, in recent years, the research focus of scientific researchers has gradually shifted to simplifying operating procedures, shortening analysis time, and improving pretreatment efficiency.

[0003] Among them, magnetic dispersed solid phase extraction (MDSPE) is an important form of dispersed solid phase extraction (d-SPE), which uses an external magnetic field to achieve solid-liquid separation of magnetic materials and sample solutions. Compared with the traditional d-SPE method, MDSPE fully disperses the adsorbent through magnetic stirring, vortexing or ultrasonic treatment, thereby increasing the contact area between the analyte and the adsorbent and enhancing the extraction efficiency. After extraction, the magnetic adsorbent can be directly separated by an external magnetic field without filtering or centrifugation, thereby simplifying the operation process, reducing sample processing steps, and improving extraction efficiency.

[0004] In practical applications, for some analytes, due to their low sensitivity in direct detection, derivatization is usually required in sample pretreatment to convert the analytes into derivatives that are easier to detect, thereby improving chromatographic separation and increasing detection sensitivity. In addition, derivatization reactions often require a specific pH environment, so a pH regulator needs to be added to ensure that the reaction proceeds smoothly or accelerate the reaction rate. In addition, in the pretreatment of some easily ionized analytes, pH regulators can be used to control the molecular state of the analyte, making it easier to be adsorbed, thereby improving the extraction recovery rate.

[0005] However, the traditional sample pretreatment process usually separates the extraction, derivatization and pH adjustment steps, which not only increases the operation steps and experimental complexity, but also prolongs the pretreatment time, increases manpower consumption, and reduces experimental efficiency. Therefore, how to further simplify the sample pretreatment process and more effectively improve the pretreatment efficiency and detection sensitivity is of great significance for the chromatographic detection of complex matrix samples. Summary of the invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a multifunctional magnetic adsorbent, which adopts a one-pot grinding method to prepare an adsorbent material with integrated adsorption, derivatization, pH adjustment and magnetic functions. It is not only simple to operate and has high repeatability, but also when the prepared multifunctional magnetic adsorbent is used for sample pretreatment, it can significantly simplify the sample processing process, improve the convenience of the method, and effectively improve the pretreatment efficiency and detection sensitivity.

[0007] The purpose of the present invention is also to provide a multifunctional magnetic adsorbent prepared by the above-mentioned preparation method and its application, as well as a method for detecting a target analyte using the above-mentioned multifunctional magnetic adsorbent. By using the multifunctional magnetic adsorbent for the extraction and derivatization of the target analyte, the qualitative and quantitative detection efficiency of the target analyte can be improved.

[0008] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a multifunctional magnetic adsorbent, comprising the following steps: mixing a magnetic material, an adsorbent, a pH regulator, and a derivatizing agent and grinding them uniformly to obtain the multifunctional magnetic adsorbent.

[0009] As a preferred embodiment of the present invention, the magnetic material is one or more of Fe3O4 nanoparticles, Fe2O3 nanoparticles, CoFe2O4 cobalt ferrite, NiFe2O4 nickel ferrite, and Fe3O4@SiO2 magnetic silica.

[0010] As a preferred embodiment of the present invention, the adsorbent is one or more of hydroxylated multi-walled carbon nanotubes, graphene, polypyrrole, polyaniline, metal organic framework materials, and covalent organic framework materials.

[0011] As a preferred embodiment of the present invention, the pH regulator is a solid acid-base regulator; the solid acid-base regulator is one or more of calcium oxide, citric acid, citrate, borax, potassium dihydrogen phosphate, and disodium hydrogen phosphate.

[0012] The present invention does not specifically limit the type of derivatization reagent, and technicians can routinely select a derivatization reagent in solid form that specifically reacts with the target analyte. As a preferred embodiment of the present invention, the derivatization reagent is one of 2,4-dinitrophenylhydrazine, 3-nitrophenylhydrazine, 2,3-diaminonaphthalene, fluorescamine, and dansyl chloride.

[0013] As a preferred embodiment of the present invention, the mass ratio of the magnetic material, the adsorbent, the pH adjuster, and the derivatization agent is (3-5):(0.5-2):(0.5-15):(0.5-2).

[0014] The second aspect of the present invention provides a multifunctional magnetic adsorbent prepared by the above preparation method.

[0015] The third aspect of the present invention provides the application of the above-mentioned multifunctional magnetic adsorbent in detecting target analytes; the target analytes are small molecule compounds; the small molecule compounds are one or more of furfural compounds, α-dicarbonyl compounds, carboxylic acid compounds, amino compounds, and thiol compounds.

[0016] The present invention does not specifically limit the types of target analytes, and technicians can routinely select small molecule compounds containing specific groups and that can be derivatized as target analytes. For example, when selecting target analytes, furfural compounds include but are not limited to 5-hydroxymethylfurfural, furfural, and 5-methylfurfural. α-Dicarbonyl compounds include but are not limited to 3-deoxyglucose ketone, 3-deoxyglucose ketone, glyoxal, methylglyoxal, diacetyl, and pentanedione. Carboxylic acid compounds include but are not limited to citric acid and butyric acid. Amino compounds include but are not limited to aniline and ethylenediamine. Sulfhydryl compounds include but are not limited to cysteine ​​and glutathione.

[0017] The fourth aspect of the present invention provides a method for detecting a target analyte using the above-mentioned multifunctional magnetic adsorbent, comprising the following steps: using the multifunctional magnetic adsorbent to extract and derivatize a sample solution containing the target analyte, then washing and desorbing the product obtained after the treatment under the action of an external magnetic field, and then subjecting the obtained desorbed liquid to instrumental analysis, thereby achieving detection of the target analyte.

[0018] As a preferred embodiment of the present invention, the extraction derivatization treatment is to mix the multifunctional magnetic adsorbent and the sample solution containing the target analyte and then perform a shaking treatment; the shaking treatment time is 10 to 60 minutes.

[0019] The advantages and beneficial effects of the technical solution of the present invention are:

[0020] The preparation method of the multifunctional magnetic adsorbent provided by the present invention comprises mixing and grinding a magnetic material, an adsorbent, a pH regulator, and a derivatization reagent, and using a one-pot grinding method to realize the self-assembly of the materials, thereby preparing the multifunctional magnetic adsorbent. The multifunctional magnetic adsorbent integrates the functions of magnetism, adsorption, pH regulation, and derivatization at the same time, and can effectively simplify the pre-treatment process of the sample.

[0021] The above method of the present invention adopts a highly integrated strategy, and the preparation process is simple and stable. The multifunctional magnetic adsorption material can be obtained only by uniform grinding. When using the material for sample pretreatment, there is no need to add additional pH adjusters or derivatization reagents, which can simplify the operation steps, reduce operation errors, shorten the processing time, and improve detection efficiency. In addition, the material can be used for dispersed magnetic solid phase extraction, and rapid liquid-solid separation is achieved with the help of magnets without centrifugation or filtration, which is conducive to further simplifying the operation steps and achieving efficient derivatization and enrichment of target analytes.

[0022] The multifunctional magnetic adsorbent prepared by the present invention has excellent pH adjustment ability and derivatization function, and is suitable for high-sensitivity analysis and detection of complex matrix samples, and is particularly suitable for the analysis of small molecule compounds. Therefore, the present invention can provide a new technical path for the efficient separation, enrichment and sensitive detection of target compounds in complex samples, and also expand the application potential of magnetic adsorption materials in the field of chemical analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a method for preparing the multifunctional magnetic adsorbent and a flow chart for detecting the target analyte;

[0024] Figure 2 The liquid chromatograms of three furfural compounds detected by the multifunctional magnetic adsorbent of Example 1 of the present invention are shown;

[0025] Figure 3 The liquid chromatograms of six α-dicarbonyl compounds detected by the multifunctional magnetic adsorbent of Example 2 of the present invention;

[0026] in, Figure 1 In the figure: 1 is a magnetic material, 2 is an adsorbent, 3 is a pH regulator, 4 is a derivatization reagent, 5 is a mortar, 6 is a multifunctional magnetic adsorbent, 7 is a centrifuge tube, 8 is a sample solution, and 9 is an external magnet. DETAILED DESCRIPTION

[0027] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. It should be noted that, in the case of no conflict, the features in the embodiments of the present invention and the embodiments can be combined with each other. The raw materials and preparation methods used in the following embodiments are all conventional materials and techniques in the art unless otherwise specified.

[0028] The invention provides a method for preparing a multifunctional magnetic adsorbent, comprising the following steps: mixing a magnetic material, an adsorbent, a pH regulator and a derivatizing agent and grinding them uniformly to obtain the multifunctional magnetic adsorbent.

[0029] As a preferred embodiment, the magnetic material is one or more of Fe3O4 nanoparticles, Fe2O3 nanoparticles, CoFe2O4 cobalt ferrite, NiFe2O4 nickel ferrite, and Fe3O4@SiO2 magnetic silica.

[0030] Specifically, the preparation method of the functional magnetic adsorbent involved in the following embodiments and the flow chart of detecting the target analyte are as follows: Figure 1 shown. Figure 1 In the method, a magnetic material 1, an adsorbent 2, a pH regulator 3, and a derivatization reagent 4 are first mixed and then ground evenly in a mortar 5 to obtain a multifunctional magnetic adsorbent 6; the multifunctional magnetic adsorbent 6 is placed in a centrifuge tube 7, and then a sample solution 8 is added to perform extraction and derivatization treatment, and finally, under the action of the magnetic field of an external magnet 9, the product obtained after the extraction and derivatization treatment is cleaned and desorbed, and then the obtained desorption liquid is subjected to instrumental analysis, thereby achieving the detection of the target analyte.

[0031] As a preferred embodiment, the adsorbent is one or more of hydroxylated multi-walled carbon nanotubes, graphene, polypyrrole, polyaniline, metal organic framework materials, and covalent organic framework materials.

[0032] As a preferred embodiment, the pH regulator is a solid acid-base regulator; the solid acid-base regulator is one or more of calcium oxide, citric acid, citrate, borax, potassium dihydrogen phosphate, and disodium hydrogen phosphate.

[0033] The derivatization reagent is solid and has the function of reacting specifically with the target analyte. As a preferred embodiment, the derivatization reagent is one of 2,4-dinitrophenylhydrazine, 3-nitrophenylhydrazine, 2,3-diaminonaphthalene, fluorescamine, and dansyl chloride.

[0034] As a preferred embodiment of the present invention, the mass ratio of the magnetic material, adsorbent, pH adjuster and derivatization agent is (3-5):(0.5-2):(0.5-15):(0.5-2). Further preferably, the mass ratio of the magnetic material, adsorbent, pH adjuster and derivatization agent is 4:1:(1-7.5):1.

[0035] The present invention also provides an application of a multifunctional magnetic adsorbent prepared by the above preparation method, and the application in detecting a target analyte; the target analyte is a small molecule compound; the small molecule compound is one or more of furfural compounds, α-dicarbonyl compounds, carboxylic acid compounds, amino compounds, and thiol compounds. Among them, furfural compounds include but are not limited to 5-hydroxymethylfurfural, furfural, and 5-methylfurfural. α-dicarbonyl compounds include but are not limited to 3-deoxyglucose ketone, 3-deoxyglucose ketone, glyoxal, methylglyoxal, diacetyl, and pentanedione. Carboxylic acid compounds include but are not limited to citric acid and butyric acid. Amino compounds include but are not limited to aniline and ethylenediamine. Thiol compounds include but are not limited to cysteine ​​and glutathione.

[0036] Furthermore, for the detection of furfural compounds, the derivatization reagent is preferably 2,4-dinitrophenylhydrazine. For the detection of α-dicarbonyl compounds, the derivatization reagent is preferably 2,3-diaminonaphthalene.

[0037] The present invention also provides a method for detecting a target analyte using the multifunctional magnetic adsorbent, comprising the following steps: using the multifunctional magnetic adsorbent to extract and derivatize a sample solution containing the target analyte, then washing and desorbing the product obtained after the treatment under the action of an external magnetic field, and then subjecting the obtained desorbed liquid to instrumental analysis, thereby achieving detection of the target analyte.

[0038] As a preferred embodiment, the extraction derivatization treatment is to mix the multifunctional magnetic adsorbent and the sample solution containing the target analyte and then perform a shaking treatment; the shaking treatment time is 10 to 60 minutes.

[0039] As a preferred embodiment, the external magnetic field can be realized by an external magnet. The cleaning is performed by water. The desorption is performed by an organic solvent. For example, the organic solvent can be a conventional desorption solvent such as acetonitrile, acetone, etc.

[0040] As a preferred embodiment, the instrument used for instrumental analysis is selected from one of ultraviolet-visible spectrophotometer (UV-Vis), high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS).

[0041] The multifunctional magnetic adsorbent prepared by the present invention integrates adsorption, derivatization, pH adjustment and magnetic functions. When applied to the detection of target analytes, the target analytes and the multifunctional magnetic adsorbent can be adsorbed by one or more of hydrogen bonding, ion exchange, hydrophobic interaction, hydrophilic interaction, complexation or π-π interaction, and then liquid-solid separation is carried out under the action of an external magnetic field. The whole process has high integration and is easy to operate, can improve the pre-treatment efficiency of samples, and can reduce the operation steps and experimental errors.

[0042] The following examples respectively use three furfural compounds and six α-dicarbonyl compounds as target analytes to be detected to illustrate the preparation method and application of the multifunctional magnetic adsorbent of the present invention. In other embodiments, the target analytes to be detected may also be other target analytes that require pH adjustment and derivatization pretreatment. As long as they are within the technical concept of the present invention, they can also achieve the detection effect of the present invention. Therefore, the present invention does not specifically limit the type of target analytes. Among them, the hydroxylated multi-walled carbon nanotubes involved in the following embodiments are from the Shanghai Aladdin brand, and the ferrosoferric oxide nanoparticles are from the Xianfeng Nano brand.

[0043] Example 1

[0044] This embodiment takes the detection of three furfural targets as an example to illustrate the preparation method and application of the multifunctional magnetic adsorbent of the present invention. Specifically, this embodiment provides a multifunctional magnetic adsorbent that integrates pH adjustment and derivatization functions, and can achieve effective detection of three furfural targets: 5-hydroxymethylfurfural (5-HMF), furfural (F), and 5-methylfurfural (MF). The preparation method and detection process of the multifunctional magnetic adsorbent include the following steps:

[0045] (1) Preparation of multifunctional magnetic adsorbent: Weigh 8 g of ferrosoferric oxide nanoparticles (Fe3O4), 2 g of hydroxylated multi-walled carbon nanotubes (MWCNTs-OH), 15 g of citric acid and 2 g of 2,4-dinitrophenylhydrazine (DNPH), put them in a mortar and grind them thoroughly until a uniform powder is formed, thereby preparing a multifunctional magnetic adsorbent.

[0046] (2) Derivatization and extraction: Weigh 27 mg of the multifunctional magnetic adsorbent prepared in step (1) and place it in a 2 mL centrifuge tube. Dilute the aqueous solution containing the three furfural mixed standards with ethanol in equal volumes, take 3 mL of the furfural mixed standard dilution solution (the concentration of each furfural standard is 10 μg / mL) and add it to the centrifuge tube containing the multifunctional magnetic extraction material, and shake it at room temperature at a speed of 1500 rpm for 30 minutes to complete the derivatization and extraction process. After the derivatization product is adsorbed on the surface of the magnetic material, an external magnet is used to aggregate the product to the wall of the centrifuge tube, and the liquid in the centrifuge tube is removed. Subsequently, 0.3 mL of pure water is added to the centrifuge tube, vortexed for 10 seconds to wash the adsorbent material, and the washing liquid is removed with a magnet. Finally, 100 μL of acetonitrile is added, vortexed for 1.5 minutes for desorption, and the magnetic material is collected by a magnet to remove the desorbed liquid. After the desorbed liquid is filtered through a 0.22 μm filter membrane, 20 μL of the sample is sampled for liquid chromatography analysis.

[0047] (3) Analysis and detection: Chromatographic analysis was performed using an Agilent 1100 liquid chromatograph (Agilent Technologies, Palo Alto, CA, USA), equipped with an online degasser, a quaternary pump, and an ultraviolet detector (UV). The chromatographic column used was Agilent TC-C18 (250×4.6 mm, 5 μm), the column temperature was 30°C, the flow rate was 1 mL / min, the injection volume was 20 μL, and the ultraviolet detection wavelength was 360 nm. The derivatized products of the three furfural target compounds were separated by isocratic elution with 65% acetonitrile.

[0048] At the same time, a blank group test is carried out, and a blank sample solution without the target is used to replace the furfural mixed standard dilution in step (2), and the multifunctional magnetic adsorbent of step (1) is used to perform derivatization extraction and analytical detection on the blank sample solution, and the specific operation steps are the same as in Example 1. In addition, the furfural mixed standard dilution (the concentration of each furfural standard is 10 μg / mL) is only subjected to conventional derivatization treatment, and analytical detection is performed to perform a control group test. The specific steps of the control group test are as follows: 3mL of the furfural mixed standard dilution is taken in a 2mL centrifuge tube, 200μL of 2mg / mL 2,4-dinitrophenylhydrazine (DNPH) acetonitrile solution is added, and 50μL of 0.1M hydrochloric acid solution is added to adjust the pH to promote the derivatization reaction. The mixed solution is shaken at a speed of 1500rpm for 30min at room temperature to ensure that the target reacts fully with the derivatization reagent. Subsequently, 100μL of the reaction solution is taken, filtered through a 0.22μm filter membrane, and 20μL of the sample is directly injected into a liquid chromatograph for analytical detection.

[0049] Figure 2 Shown is a liquid chromatogram of the multifunctional magnetic adsorbent used for target detection. Figure 2 In the figure, spectrum a is a liquid chromatogram of the furfural mixed standard dilution solution after derivatization and extraction treatment by the multifunctional magnetic adsorbent of Example 1 of the present invention; spectrum b is a chromatogram of the furfural mixed standard dilution solution only subjected to solution derivatization treatment and then directly subjected to chromatographic analysis (control group); spectrum c is a chromatogram of the blank sample solution after derivatization and extraction by the multifunctional magnetic adsorbent of Example 1 of the present invention (blank group).

[0050] Figure 2 The results show that the target derivatization product peaks of the three furfural compounds in spectrum a are clearly visible, and the peak height is significantly higher than that in spectrum b. At the same time, no target product peaks were detected in the blank sample solution (spectrum c), indicating no interference. The above results show that the multifunctional magnetic adsorbent constructed by the present invention can achieve derivatization and extraction at the same time, significantly improving the detection sensitivity while reducing the experimental operation steps.

[0051] Example 2

[0052] This embodiment takes the detection of six α-dicarbonyl compounds (α-DCs) as an example to illustrate the preparation method and application of the multifunctional magnetic adsorbent of the present invention. Specifically, this embodiment provides a multifunctional magnetic adsorbent that integrates pH adjustment and derivatization functions, and can achieve effective detection of six α-dicarbonyl compounds: 3-deoxyglucose ketone (DS), 3-deoxyglucose ketone (3-DG), glyoxal (GO), methylglyoxal (MGO), diacetyl (DA), and pentanedione (PD). The preparation method and detection process of the multifunctional magnetic adsorbent specifically include the following steps:

[0053] (1) Preparation of multifunctional magnetic adsorbent: Weigh 4 g of ferrosoferric oxide (Fe3O4), 1 g of hydroxylated multi-walled carbon nanotubes (MWCNTs-OH), 1 g of 2,3-diaminonaphthalene (DMN) and 1 g of buffer salt powder (the buffer salt is composed of equimolar potassium dihydrogen phosphate (KH2PO4) and disodium hydrogen phosphate (Na2HPO4)), add them into a mortar and grind them evenly until a uniform powder is formed to achieve self-assembly, thereby preparing a multifunctional magnetic adsorbent.

[0054] (2) Derivatization and extraction: Weigh 7 mg of the multifunctional magnetic adsorbent prepared in step (1) and add it to a 2 mL centrifuge tube, then add 1 mL of a mixed standard solution containing six α-dicarbonyl compound standards (the concentration of each α-dicarbonyl compound is 10 μM, and the solvent is water), and shake at a constant temperature of 60°C for 40 minutes to complete the derivatization and extraction process. The derivatized product is extracted onto the adsorbent material. Use an external magnet to aggregate the derivative product to the wall of the centrifuge tube, and easily remove the clear liquid in the centrifuge tube. Then add 0.3 mL of pure water and vortex for 10 seconds to clean the adsorbent material. Use an external magnet to aggregate it to the wall of the centrifuge tube, and easily remove the cleaning solution. Finally, add 150 μL of acetonitrile, vortex for 1 minute for desorption, use an external magnet to aggregate it to the wall of the centrifuge tube, and easily remove the desorbed liquid. After filtering the desorbed liquid through a 0.22 μm filter membrane, sample 10 μL for liquid chromatography analysis.

[0055] (3) Analysis and detection: Chromatographic analysis was performed using an Agilent 1100 liquid chromatograph (Agilent Technologies, Palo Alto, CA, USA), equipped with an online degasser, a quaternary pump, and a fluorescence detector (FLD). The chromatographic column was Agilent TC-C18 (250×4.6 mm, 5 μm). The mobile phase A was water and B was acetonitrile. Gradient elution was used to separate the six α-DCs. The specific elution procedure was as follows: 26% B in the first 10 minutes, increased to 45% B at 10.5 minutes and maintained until 25 minutes; increased to 80% B at 26 minutes and maintained for 8 minutes, then adjusted back to the initial ratio and balanced for 5 minutes. The column temperature was set at 30°C, the flow rate was 1 mL / min, the injection volume was 10 μL, the excitation wavelength for fluorescence detection was 267 nm, and the emission wavelength was 500 nm.

[0056] The blank group and control group experiments were carried out at the same time. In the control group experiment, only the mixed standard solution containing six α-dicarbonyl compound standards (the concentration of each α-dicarbonyl compound was 10 μM) was subjected to conventional derivatization treatment. The specific operation is as follows: 1 mL of the mixed standard solution is taken in a 2 mL centrifuge tube, and 50 μL of DMN solution (20 mM, prepared in MeOH) and 100 μL of phosphate buffer solution (50 mM, pH 7.0) are added to adjust the pH to promote the derivatization reaction. The mixed solution was kept at a constant temperature of 60 ° C for 40 min to ensure that the target reacts fully with the derivatization reagent. Subsequently, 100 μL of the reaction solution was taken, filtered through a 0.22 μm filter membrane, and 10 μL of the sample was directly injected into the liquid chromatograph for analysis and detection. At the same time, a blank solution without a standard was used to replace the mixed standard solution of Example 1 of the present invention, and the mixed standard solution of the conventional derivatization process of the above-mentioned control group, and two blank tests were carried out.

[0057] Figure 3 The liquid chromatograms of the multifunctional magnetic adsorbent used for target detection in Example 2 are shown. Spectrum a is a chromatogram of the mixed standard solution after derivatization and extraction by the multifunctional magnetic adsorbent in Example 2; Spectrum b is a chromatogram of the mixed standard solution after conventional derivatization; Spectra c and Spectrum d are chromatograms of the blank solution after derivatization and extraction by the multifunctional magnetic adsorbent and conventional derivatization, respectively.

[0058] Figure 3The results show that the target product peak in spectrum a is significantly higher than that in spectrum b, indicating that the extraction and enrichment effect is good. By comparing the area of ​​the product peaks in a and b, it is calculated that the extraction recovery rate of the method is 57%-80%, and the enrichment factor is 3.8-5.3 times. The effectiveness of the magnetic adsorbent of the present invention is further verified. In addition, by comparing with spectrum c and spectrum d, it can be seen that the chromatographic retention time of the derivatization reagent is consistent with that of the experimental group, and no additional interference peaks appear, which proves that the method has good specificity. The experimental results of this embodiment show that the magnetic adsorbent shows good effects in extracting and enriching target analytes, can significantly improve the detection sensitivity, and has been successfully applied to the analysis and detection of six α-DCs.

[0059] In summary, the present invention adopts a one-pot grinding method to prepare a multifunctional magnetic adsorbent, which can effectively improve the efficiency and convenience of material preparation and sample pretreatment processes. Through the magnetic separation characteristics and multifunctional integration characteristics of the multifunctional material, efficient derivatization extraction and detection of target analytes in samples can be achieved. Compared with the prior art, the present invention has significant advantages in terms of ease of operation. At the same time, the present invention uses furfural compounds and α-dicarbonyl compounds as examples to explain and verify the application effects of the present invention in detail. Therefore, the present invention can provide a new technical path for the efficient separation, enrichment and sensitive detection of target compounds in complex samples, and also expand the application potential of magnetic adsorption materials in the field of chemical analysis.

[0060] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for preparing a multifunctional magnetic adsorbent, characterized in that: The method comprises the following steps: mixing a magnetic material, an adsorbent, a pH regulator and a derivatizing agent and then grinding them uniformly to obtain the multifunctional magnetic adsorbent.

2. The method for preparing the multifunctional magnetic adsorbent according to claim 1, characterized in that: The magnetic material is one or more of Fe3O4 nanoparticles, Fe2O3 nanoparticles, CoFe2O4 cobalt ferrite, NiFe2O4 nickel ferrite, and Fe3O4@SiO2 magnetic silicon dioxide.

3. The method for preparing the multifunctional magnetic adsorbent according to claim 1, characterized in that: The adsorbent is one or more of hydroxylated multi-walled carbon nanotubes, graphene, polypyrrole, polyaniline, metal organic framework materials, and covalent organic framework materials.

4. The method for preparing the multifunctional magnetic adsorbent according to claim 1, characterized in that: The pH regulator is a solid acid-base regulator; the solid acid-base regulator is one or more of calcium oxide, citric acid, citrate, borax, potassium dihydrogen phosphate, and disodium hydrogen phosphate.

5. The method for preparing the multifunctional magnetic adsorbent according to claim 1, characterized in that: The derivatization reagent is one of 2,4-dinitrophenylhydrazine, 3-nitrophenylhydrazine, 2,3-diaminonaphthalene, fluorescamine and dansyl chloride.

6. The method for preparing a multifunctional magnetic adsorbent according to any one of claims 1 to 5, characterized in that: The mass ratio of the magnetic material, the adsorbent, the pH regulator and the derivatization reagent is (3-5): (0.5-2): (0.5-15): (0.5-2).

7. A multifunctional magnetic adsorbent prepared by the preparation method according to any one of claims 1 to 6.

8. A use of the multifunctional magnetic adsorbent as claimed in claim 7, characterized in that: Application in detecting target analytes; the target analytes are small molecule compounds; the small molecule compounds are one or more of furfural compounds, α-dicarbonyl compounds, carboxylic acid compounds, amino compounds, and thiol compounds.

9. A method for detecting a target analyte using the multifunctional magnetic adsorbent as claimed in claim 7, characterized in that: The following steps are involved: The multifunctional magnetic adsorbent is used to extract and derivatize a sample solution containing a target analyte, and then the product obtained after the treatment is cleaned and desorbed under the action of an external magnetic field, and the obtained desorbed liquid is then subjected to instrumental analysis, thereby achieving detection of the target analyte.

10. The method for detecting a target analyte using a multifunctional magnetic adsorbent according to claim 9, characterized in that: The extraction derivatization treatment is to mix the multifunctional magnetic adsorbent and the sample solution containing the target analyte and then perform a shaking treatment; the shaking treatment time is 10 to 60 minutes.

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