Method for rapidly detecting aflatoxin B1 in food

Abstract

The invention discloses a method for rapidly detecting aflatoxin B1 in food, amino is modified by maltitol and then grafted to the surface of an aluminum metal composite carrier to form a polyhydroxy shielding layer, the binding energy of hydroxyl and water molecules is far higher than that of the amino and water, and the hydroxyl and the water molecules preferentially form strong hydrogen bonds, so that the aflatoxin B1 in the food can be rapidly detected. According to the present invention, the hydrophobic alkyl chain of the water-blocking agent is directionally arranged to block the competitive binding of the water molecule to the amino group, and the hydrophobic alkyl chain is directionally arranged to repel the free water molecule, and the specific hydrogen-bond interaction of the amino group and the methoxyl group in the aflatoxin B1 is retained, such that the aflatoxin B1 in the high-moisture food can be rapidly adsorbed so as to effectively avoid the influence of the water molecule on the aflatoxin B1 detection precision; the step of adsorbing the aflatoxin B1 in the high-moisture food is reduced, and the detection accuracy and rapidness are further improved.

Description

Technical Field

[0001] This invention relates to the field of food testing, and more particularly to a method for rapid detection of aflatoxin B1 in food. Background Technology

[0002] Aflatoxin B1 is a difuran ring toxin produced by certain strains of Aspergillus flavus, Aspergillus parasiticus, and other fungi. It is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC). It has approximately 20 derivatives, which can cause cancer, birth defects, and mutations in organisms even at extremely low concentrations. Aflatoxin B1 is one of the most readily produced and toxic metabolites of agricultural products during harvesting, storage, and processing. It is heat-resistant and chemically stable. Currently, the main methods for detecting aflatoxin B1 in food include high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS / MS), and immunological methods (such as ELISA kits and immunochromatographic test strips). While these methods offer high sensitivity and accuracy, they typically rely on complex and time-consuming sample pretreatment processes to purify the sample and enrich the target analyte, eliminating interference from the complex food matrix and improving detection sensitivity. Traditional sample pretreatment techniques, such as solid-phase extraction (SPE), while effective, are cumbersome, time-consuming, and require professional personnel, making them unsuitable for rapid on-site screening.

[0003] In recent years, nanomaterials have been widely used in sample pretreatment due to their unique physicochemical properties. Among them, magnetic nanomaterials, especially iron(III) oxide (Fe3O4) nanoparticles, have shown great application potential because they can be rapidly separated by an external magnetic field, greatly simplifying the operation process. Metal-organic frameworks (MOFs) are also considered an excellent adsorbent platform due to their high specific surface area, tunable pore structure, and ease of functionalization. Aluminum-centered MOFs (Al-MOFs) are favored for their low cost, low toxicity, and high stability.

[0004] Existing methods for aflatoxin B1 enrichment / purification in high-moisture foods (fruit juice, milk, soy sauce, etc.) are complex because they require a systematic approach to address several issues: defatting / deproteinizing / depigmenting / desugaring / phase separation / concentration. This involves organic extraction or methanol / acetonitrile extraction, followed by salting out or solvent separation to overcome emulsification, centrifugation to remove suspended solids, selective enrichment using SPE or immunoaffinity columns, and often evaporation and resolution or derivatization. This process is not only time-consuming and solvent-intensive, requiring highly skilled operators, but each step also carries the risk of loss, such as incomplete adsorption, incomplete elution, carrier overload or blockage, and cross-contamination. This leads to false negatives / false positives or fluctuations in recovery rates. Directly applying such materials to the adsorption and enrichment of aflatoxin B1 in high-moisture foods (such as juice, milk, and soy sauce) still faces significant challenges. The typical adsorption mechanism of aflatoxin B1 molecules relies on hydrogen bonds formed between the carbonyl (C=O) and methoxy (-OCH3) groups on its furan ring and functional groups such as amino (-NH2) groups on the adsorbent surface. However, in high-moisture environments, a large number of water molecules preferentially bind to amino groups, forming competitive hydrogen bonds (H2O...HN), severely shielding the interaction between the amino group and the aflatoxin B1 target molecule, resulting in a significant decrease in adsorption capacity and selectivity. Therefore, it is necessary to design a rapid method for the detection of aflatoxin B1 in food. Summary of the Invention

[0005] This invention overcomes the shortcomings of the prior art and provides a method for rapid detection of aflatoxin B1 in food.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for rapid detection of aflatoxin B1 in food, comprising the following steps:

[0007] Step S1: Prepare aluminum metal composite adsorbent material;

[0008] Step S2: Adsorb and enrich aflatoxin B1 in high-moisture food samples using aluminum metal composite adsorbent material;

[0009] Step S3: Separate the adsorbent from the food matrix using magnetic separation.

[0010] Step S4: Elute the aflatoxin B1 on the adsorbent using an organic solvent;

[0011] Step S5: Quantitatively detect aflatoxin B1 in the eluent.

[0012] In a preferred embodiment of the present invention, the preparation of the aluminum metal composite adsorbent material in step S1 includes the following sub-steps:

[0013] Step S11: Load iron oxide nanoparticles onto an aluminum metal framework to obtain an aluminum metal composite carrier;

[0014] Step S12: Mix maltitol with 3-aminopropyltriethoxysilane ethanol solution to modify the amino group in 3-aminopropyltriethoxysilane.

[0015] Step S13: Immerse the aluminum metal composite carrier in the modified amino solution of step S12 to modify the surface of the aluminum metal composite carrier with modified amino.

[0016] In a preferred embodiment of the present invention, step S11 includes the following sub-steps:

[0017] Step S111: Select a porous aluminum alloy microplate with a pore size of 50-100μm as the aluminum metal skeleton;

[0018] Step S112: Dissolve FeCl3·6H2O and FeCl2·4H2O in deionized water at a molar ratio of 2-3:1, add 25-30% ammonia water dropwise under nitrogen protection until the pH is 10-11, and react at 60-80℃ for 0.5-1h to generate Fe3O4 particles with a particle size of 50-100nm.

[0019] Step S113: Disperse Fe3O4 particles in N,N-dimethylformamide, add an aluminum metal skeleton, and vacuum impregnate at 55-75℃ for 1-2.5h to form an aluminum metal composite carrier.

[0020] Step S114: Dry the aluminum metal composite carrier at 60-75℃ for 10-12 hours, and then anneal the dried aluminum metal composite carrier at 300-350℃ for 0.5-1 hours.

[0021] In a preferred embodiment of the present invention, in step S113, Fe3O4 particles are dispersed in N,N-dimethylformamide to obtain a dispersion with a concentration of 3-5 mg / mL.

[0022] In a preferred embodiment of the present invention, in step S12, the concentration of the 3-aminopropyltriethoxysilane ethanol solution is 3-5%.

[0023] In a preferred embodiment of the present invention, step S12 includes:

[0024] Maltitol and 3-aminopropyltriethoxysilane ethanol solution are mixed at a mass ratio of 1-3:1, and the mixture is heated to 55-70℃ and stirred at 200-300 rpm for 1-2 hours.

[0025] The stirred mixture was dried at 50-60℃ for 20-30 minutes to obtain a viscous crude product.

[0026] The viscous crude product was washed with anhydrous diethyl ether to remove unreacted 3-aminopropyltriethoxysilane, and then dried under vacuum at 50-60°C for 10-12 h to obtain the modified amino group.

[0027] In a preferred embodiment of the present invention, step S13 includes the following sub-steps:

[0028] Step S131: Dissolve the modified amino group in anhydrous ethanol to prepare an impregnation solution with a concentration of 5-10%.

[0029] Step S132: Clean the aluminum metal composite carrier with acetone by ultrasonic cleaning for 10-15 min, and then vacuum dry it at 70-80℃ for 1-1.5 h.

[0030] Step S133: Immerse the aluminum metal composite carrier processed in step S132 into the impregnation solution, keep it at a constant temperature of 50-60℃, and stir at a speed of 200-300 rpm for 2-3 hours.

[0031] In a preferred embodiment of the present invention, in step S133, the mass ratio of the impregnation liquid to the aluminum metal composite carrier is 20-25:1.

[0032] In a preferred embodiment of the present invention, the modified amino groups of the aluminum metal composite adsorbent material are bonded to aflatoxin B1 in a high-moisture food sample via hydrogen bonds.

[0033] The organic solvent includes an acetonitrile-acetic acid solution, wherein the mass ratio of acetonitrile to acetic acid is 9-10:1.

[0034] In a preferred embodiment of the present invention, the quantitative detection is performed using an immunochromatographic test strip method or a high-performance liquid chromatography method.

[0035] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0036] (1) This invention provides a method for rapid detection of aflatoxin B1 in food. The amino group is modified by maltitol and grafted onto the surface of an aluminum metal composite carrier to form a multi-hydroxyl shielding layer. Since the binding energy of hydroxyl groups with water molecules is much higher than that of amino groups with water, hydroxyl groups preferentially form strong hydrogen bonds with water molecules, blocking the competitive binding of water molecules to amino groups. At the same time, the hydrophobic alkyl chains are oriented to repel free water molecules and retain the specific hydrogen bond between amino groups and methoxy groups in aflatoxin B1. This allows for rapid adsorption of aflatoxin B1 in high-moisture foods, effectively avoiding the influence of water molecules on the accuracy of aflatoxin B1 detection, reducing the adsorption steps for aflatoxin B1 in high-moisture foods, and further improving the accuracy and speed of detection.

[0037] (2) This invention provides a method for rapid detection of aflatoxin B1 in food. By modifying the amino group with maltitol, the modified polymer chain is fully extended in the aqueous phase. Through the interaction between its large number of hydroxyl groups and water molecules, the continuous water molecule network structure in high-moisture food is effectively disrupted, and the diffusion resistance of aflatoxin B1 molecules in viscous aqueous phase is reduced.

[0038] (3) This invention provides a method for rapid detection of aflatoxin B1 in food. By using aluminum metal as a framework and introducing iron oxide nanoparticles, a stable porous composite structure is formed, which effectively improves the dispersibility of the adsorbent under high moisture conditions, reduces the problem of decreased specific surface area and mass transfer efficiency caused by nanoparticle aggregation, and enables aflatoxin B1 to diffuse rapidly and bind to the active site, thereby shortening the detection time and increasing the adsorption capacity. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0041] A method for rapid detection of aflatoxin B1 in food includes the following steps:

[0042] Step S1: Prepare aluminum metal composite adsorbent material;

[0043] Step S2: Adsorb and enrich aflatoxin B1 in high-moisture food samples using aluminum metal composite adsorbent material;

[0044] Step S3: Separate the adsorbent from the food matrix using magnetic separation.

[0045] Step S4: Elute the aflatoxin B1 on the adsorbent using an organic solvent;

[0046] Step S5: Quantitatively detect aflatoxin B1 in the eluent.

[0047] In this invention, the preparation of the aluminum metal composite adsorbent material in step S1 includes the following sub-steps:

[0048] Step S11: Load iron oxide nanoparticles onto an aluminum metal framework to obtain an aluminum metal composite carrier;

[0049] Step S12: Mix maltitol with 3-aminopropyltriethoxysilane ethanol solution to modify the amino group in 3-aminopropyltriethoxysilane.

[0050] Step S13: Immerse the aluminum metal composite carrier in the modified amino solution of step S12 to modify the surface of the aluminum metal composite carrier with modified amino.

[0051] In this invention, step S11 includes the following sub-steps:

[0052] Step S111: Select a porous aluminum alloy microplate with a pore size of 50-100μm as the aluminum metal skeleton. This pore size range can ensure good fluid permeability, while providing sufficient specific surface area and attachment sites for subsequent nanoparticle loading.

[0053] Step S112: Dissolve FeCl3·6H2O and FeCl2·4H2O in deionized water at a molar ratio of 2-3:1, add 25-30% ammonia water dropwise under nitrogen protection until the pH is 10-11, and react at 60-80℃ for 0.5-1h to generate Fe3O4 particles with a particle size of 50-100nm.

[0054] Step S113: Disperse Fe3O4 particles in N,N-dimethylformamide, add an aluminum metal skeleton, and vacuum impregnate at 55-75℃ for 1-2.5h to form an aluminum metal composite carrier.

[0055] Using N,N-dimethylformamide as a dispersion / impregnation medium can improve the wettability and permeability of Fe3O4 in aluminum alloy channels. Vacuum impregnation helps to remove air from the channels and make magnetic particles uniformly loaded onto the pore walls and pore surfaces. Annealing treatment promotes the interfacial bonding between Fe3O4 and the aluminum matrix, improves the crystallinity of particles and removes organic residues, while enhancing the elution resistance and thermal stability of the particles.

[0056] Aluminum metal composite carrier enables materials to simultaneously possess a high specific surface area adsorption interface and responsive magnetic properties. After adsorbing aflatoxin B1, particles can be separated from the matrix in a very short time by applying an external magnetic field, avoiding toxin loss or matrix recontamination caused by prolonged centrifugation or filtration.

[0057] Step S114: Dry the aluminum metal composite carrier at 60-75℃ for 10-12 hours, and then anneal the dried aluminum metal composite carrier at 300-350℃ for 0.5-1 hours.

[0058] The amino group is used to adsorb aflatoxin B1 because the amino group is bonded to the carbonyl or methoxy group of aflatoxin B1 through hydrogen bonds, which can effectively adsorb aflatoxin B1 present in food.

[0059] However, considering that food is divided into many categories, including foods with high moisture content, a large number of water molecules will compete with amino groups for binding sites, forming water-amino hydrogen bonds, which in turn occupy the active sites on amino groups, weakening the targeting adsorption capacity of amino groups for aflatoxin B1. Furthermore, this will affect the adsorption capacity of amino groups for aflatoxin B1, which may lead to inaccurate detection of aflatoxin B1 in foods with high moisture content.

[0060] Therefore, the use of polyhydroxy compounds to modify amino groups, such as maltitol, aims to address the problem that water molecules in high-moisture foods affect the adsorption of aflatoxin B1 by amino groups.

[0061] Maltitol contains a large number of hydroxyl groups. Since the binding energy of hydroxyl groups to water molecules is much higher than that of amino groups to water, hydroxyl groups will occupy the binding sites of water molecules, forming a water molecule buffer and blocking the competitive binding of water molecules to amino groups.

[0062] Among them, the hydrophobic alkyl chains of maltitol are oriented to repel free water molecules and protect the specific hydrogen bonds between the amino group and the methoxy group of aflatoxin B1.

[0063] Furthermore, the modified amino group can rapidly adsorb aflatoxin B1 in high-moisture foods, effectively avoiding the influence of water molecules on the accuracy of aflatoxin B1 detection, reducing the adsorption steps for aflatoxin B1 in high-moisture foods, and further improving the accuracy and speed of detection.

[0064] In this invention, in step S113, Fe3O4 particles are dispersed in N,N-dimethylformamide to obtain a dispersion with a concentration of 3-5 mg / mL.

[0065] In this invention, in step S12, the concentration of the 3-aminopropyltriethoxysilane ethanol solution is 3-5%.

[0066] In this invention, step S12 includes:

[0067] Maltitol and 3-aminopropyltriethoxysilane ethanol solution are mixed at a mass ratio of 1-3:1, and the mixture is heated to 55-70℃ and stirred at 200-300 rpm for 1-2 hours.

[0068] The stirred mixture was dried at 50-60℃ for 20-30 minutes to obtain a viscous crude product.

[0069] The viscous crude product was washed with anhydrous diethyl ether to remove unreacted 3-aminopropyltriethoxysilane, and then dried under vacuum at 50-60°C for 10-12 h to obtain the modified amino group.

[0070] It should be noted that high-moisture foods contain a continuous bulk water network, which is the main barrier to the diffusion of aflatoxin B1. Maltitol's polyhydroxy polymer chain has strong hydrophilicity, and its large number of hydroxyl groups will strongly interact with the surrounding water molecules, disrupting the original regular and continuous hydrogen bond network structure of the water molecules.

[0071] Disruption of the water network structure is equivalent to opening up several diffusion shortcuts for hydrophobic aflatoxin B1 molecules in the viscous aqueous phase. Aflatoxin B1 molecules can more easily pass through the disrupted water network and quickly reach the adsorption sites on the material surface, thereby significantly reducing the adsorption time of aflatoxin B1.

[0072] Regarding the expansion of the lattice and deformation of pores after the porous material (such as MOF) absorbs water, aluminum metal organic frameworks (such as MIL-101(Al) and MIL-53(Al)) with extremely high water stability were used as rigid frameworks.

[0073] Considering that high-surface-area nano-Fe3O4 particles have a strong tendency to aggregate in the liquid phase due to their high surface energy and van der Waals forces, their effective specific surface area will drop sharply and block the pores, severely hindering the diffusion and contact of aflatoxin B1 molecules.

[0074] Therefore, by using aluminum metal as a framework with a regular and rigid pore structure, Fe3O4 particles are loaded into its pores or on its surface. This spatial confinement effect effectively prevents the Fe3O4 particles from approaching each other and agglomerating.

[0075] This allows the high specific surface area advantage of Fe3O4 nanoparticles to be fully utilized, providing a solid foundation for the subsequent grafting of a large number of functional molecules, such as amino groups, and ensuring the high adsorption capacity of the final aluminum metal composite adsorbent material for aflatoxin B1.

[0076] Meanwhile, the aluminum framework channels also provide a rapid transport pathway for aflatoxin B1 molecules, overcoming diffusion resistance in high-moisture environments and ensuring rapid adsorption of aflatoxin B1.

[0077] In this invention, step S13 includes the following sub-steps:

[0078] Step S131: Dissolve the modified amino group in anhydrous ethanol to prepare an impregnation solution with a concentration of 5-10%.

[0079] Step S132: Clean the aluminum metal composite carrier with acetone by ultrasonic cleaning for 10-15 min, and then vacuum dry it at 70-80℃ for 1-1.5 h.

[0080] Step S133: Immerse the aluminum metal composite carrier processed in step S132 into the impregnation solution, keep it at a constant temperature of 50-60℃, and stir at a speed of 200-300 rpm for 2-3 hours.

[0081] In this invention, in step S133, the mass ratio of the impregnation solution to the aluminum metal composite carrier is 20-25:1.

[0082] In this invention, the modified amino groups of the aluminum metal composite adsorbent material are bonded to aflatoxin B1 in high-moisture food samples via hydrogen bonds.

[0083] The organic solvent includes an acetonitrile-acetic acid solution, wherein the mass ratio of acetonitrile to acetic acid is 9-10:1.

[0084] Example 1:

[0085] A porous aluminum alloy microplate with a pore size of 50-100 μm was selected as the aluminum metal skeleton. FeCl3·6H2O and FeCl2·4H2O were dissolved in deionized water at a molar ratio of 3:1. Under nitrogen protection, 30% ammonia water was added dropwise until the pH reached 11. The reaction was carried out at 80℃ for 1 h to generate Fe3O4 particles with a particle size of 50-100 nm. The Fe3O4 particles were dispersed in N,N-dimethylformamide to obtain a dispersion with a concentration of 5 mg / mL. The aluminum metal skeleton was added and vacuum impregnated at 75℃ for 1 h to form an aluminum metal composite carrier. The aluminum metal composite carrier was dried at 60℃ for 10 h and then annealed at 350℃ for 0.5 h.

[0086] Maltitol was mixed with a 5% ethanol solution of 3-aminopropyltriethoxysilane at a mass ratio of 1:1, and the mixture was heated to 70°C and stirred at 200 rpm for 1 hour. The mixture was then dried at 50°C for 30 minutes to modify the amino group in 3-aminopropyltriethoxysilane.

[0087] Modified amino groups were dissolved in anhydrous ethanol to prepare an impregnation solution with a concentration of 5-10%. The aluminum metal composite carrier was ultrasonically cleaned with acetone for 15 min and vacuum dried at 80℃ for 1 h. The treated aluminum metal composite carrier was then immersed in the impregnation solution and stirred at 200 rpm for 2 h at a constant temperature of 50℃. The mass ratio of the impregnation solution to the aluminum metal composite carrier was 20:1, thus obtaining the aluminum metal composite adsorbent material.

[0088] Example 2:

[0089] A porous aluminum alloy microplate with a pore size of 50-100 μm was selected as the aluminum metal skeleton. FeCl3·6H2O and FeCl2·4H2O were dissolved in deionized water at a molar ratio of 3:1. Under nitrogen protection, 30% ammonia water was added dropwise until the pH reached 11. The reaction was carried out at 80℃ for 1 h to generate Fe3O4 particles with a particle size of 50-100 nm. The Fe3O4 particles were dispersed in N,N-dimethylformamide to obtain a dispersion with a concentration of 5 mg / mL. The aluminum metal skeleton was added and vacuum impregnated at 75℃ for 1 h to form an aluminum metal composite carrier. The aluminum metal composite carrier was dried at 60℃ for 10 h and then annealed at 350℃ for 0.5 h.

[0090] Maltitol was mixed with a 5% ethanol solution of 3-aminopropyltriethoxysilane at a mass ratio of 2:1, and the mixture was heated to 70°C and stirred at 200 rpm for 1 hour. The mixture was then dried at 50°C for 30 minutes to modify the amino group in 3-aminopropyltriethoxysilane.

[0091] Modified amino groups were dissolved in anhydrous ethanol to prepare an impregnation solution with a concentration of 5-10%. The aluminum metal composite carrier was ultrasonically cleaned with acetone for 15 min and vacuum dried at 80℃ for 1 h. The treated aluminum metal composite carrier was then immersed in the impregnation solution and stirred at 200 rpm for 2 h at a constant temperature of 50℃. The mass ratio of the impregnation solution to the aluminum metal composite carrier was 20:1, thus obtaining the aluminum metal composite adsorbent material.

[0092] Example 3:

[0093] A porous aluminum alloy microplate with a pore size of 50-100 μm was selected as the aluminum metal skeleton. FeCl3·6H2O and FeCl2·4H2O were dissolved in deionized water at a molar ratio of 3:1. Under nitrogen protection, 30% ammonia water was added dropwise until the pH reached 11. The reaction was carried out at 80℃ for 1 h to generate Fe3O4 particles with a particle size of 50-100 nm. The Fe3O4 particles were dispersed in N,N-dimethylformamide to obtain a dispersion with a concentration of 5 mg / mL. The aluminum metal skeleton was added and vacuum impregnated at 75℃ for 1 h to form an aluminum metal composite carrier. The aluminum metal composite carrier was dried at 60℃ for 10 h and then annealed at 350℃ for 0.5 h.

[0094] Maltitol was mixed with a 5% ethanol solution of 3-aminopropyltriethoxysilane at a mass ratio of 3:1, and the mixture was heated to 70°C and stirred at 200 rpm for 1 hour. The mixture was then dried at 50°C for 30 minutes to modify the amino group in 3-aminopropyltriethoxysilane.

[0095] Modified amino groups were dissolved in anhydrous ethanol to prepare an impregnation solution with a concentration of 5-10%. The aluminum metal composite carrier was ultrasonically cleaned with acetone for 15 min and vacuum dried at 80℃ for 1 h. The treated aluminum metal composite carrier was then immersed in the impregnation solution and stirred at 200 rpm for 2 h at a constant temperature of 50℃. The mass ratio of the impregnation solution to the aluminum metal composite carrier was 20:1, thus obtaining the aluminum metal composite adsorbent material.

[0096] Comparative Example 1:

[0097] Similar to Example 2, except that maltitol was not used for modification;

[0098] A porous aluminum alloy microplate with a pore size of 50-100 μm was selected as the aluminum metal skeleton. FeCl3·6H2O and FeCl2·4H2O were dissolved in deionized water at a molar ratio of 3:1. Under nitrogen protection, 30% ammonia water was added dropwise until the pH reached 11. The reaction was carried out at 80℃ for 1 h to generate Fe3O4 particles with a particle size of 50-100 nm. The Fe3O4 particles were dispersed in N,N-dimethylformamide to obtain a dispersion with a concentration of 5 mg / mL. The aluminum metal skeleton was added and vacuum impregnated at 75℃ for 1 h to form an aluminum metal composite carrier. The aluminum metal composite carrier was dried at 60℃ for 10 h and then annealed at 350℃ for 0.5 h.

[0099] Amino acids were dissolved in anhydrous ethanol to prepare an impregnation solution with a concentration of 5-10%. The aluminum metal composite carrier was ultrasonically cleaned with acetone for 15 min and vacuum dried at 80℃ for 1 h. The treated aluminum metal composite carrier was then immersed in the impregnation solution and stirred at 200 rpm for 2 h at a constant temperature of 50℃. The mass ratio of the impregnation solution to the aluminum metal composite carrier was 20:1, thus obtaining the aluminum metal composite adsorbent material.

[0100] Experimental preparation:

[0101] Take several portions of milk, 10 mL each, add aflatoxin B1 standard solution to each sample to make a final concentration of 5.0 μg / L, add 0.5 g NaCl, vortex for min to dissolve, and transfer to centrifuge tubes;

[0102] Place the centrifuge tubes in a constant temperature shaker and shake at 200 rpm for 20 min at 25 °C. After the reaction is complete, place the centrifuge tubes on a magnetic separator and let them stand for 1 min.

[0103] Add 5.0 mL of acetonitrile-acetic acid (9:1) to the adsorbent tube, elute by shaking for 2 min, separate and collect the eluent using a magnetic rack, blow nitrogen down to 0.5 mL, and make up to 1.0 mL of methanol / mobile phase. Detect using HPLC-FLD.

[0104] Detection:

[0105] Adsorption efficiency: (1 - average concentration in the supernatant after adding adsorbent) / initial concentration × 100%;

[0106] Adsorption equilibrium time: Under fixed conditions, the adsorption amount was measured at time points of 1 min, 2 min, 5 min, 10 min, and 30 min. At each time point, the supernatant was taken to measure the concentration or the recovery was measured by elution. When the change in adsorption amount between two or more consecutive time points is <5%, it is considered that equilibrium has been reached.

[0107] Elution recovery rate: refers to the proportion of toxins adsorbed on the aluminum metal composite adsorbent material that are eluted back into the solution. Recovery rate = (target analyte concentration in the eluent × eluent volume) / (initial sample concentration × sample volume) × 100%

[0108] Example 1 Example 2 Example 3 Comparative Example 1 Average adsorption efficiency (%) 91.2±0.2 95.7±0.1 93.1±0.3 85.8±0.2 Adsorption equilibrium time (min) 5.0±0.5 3.0 ± 0.2 4.0 ± 0.3 30.0 ± 1.0 Elution recovery rate (%) 92.5 ± 0.6 96.0 ± 0.5 94.0 ± 0.4 78.3 ± 0.9

[0109] In summary, compared with Examples 1 to 3 and Comparative Example 1, the adsorption performance of Examples 1 to 3 is much higher than that of Comparative Example 1. This is mainly because, after modifying the amino group with maltitol and grafting it onto the surface of the aluminum metal composite carrier, a multi-hydroxyl shielding layer is formed. Since the binding energy between hydroxyl groups and water molecules is much higher than that between amino groups and water, hydroxyl groups preferentially form strong hydrogen bonds with water molecules, blocking the competitive binding of water molecules to amino groups. At the same time, its hydrophobic alkyl chains are oriented to repel free water molecules and retain the specific hydrogen bonding between amino groups and the methoxy group in aflatoxin B1. This enables the rapid adsorption of aflatoxin B1 in high-moisture foods, effectively avoiding the influence of water molecules on the accuracy of aflatoxin B1 detection and reducing the number of steps required for adsorbing aflatoxin B1 in high-moisture foods.

[0110] However, when the proportion of maltitol is too high, a thick organic layer is formed, which aflatoxin B1 must penetrate to reach the amino site, thus reducing the adsorption performance.

[0111] In this invention, the quantitative detection is performed using immunochromatographic test strips or high-performance liquid chromatography.

[0112] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for rapid detection of aflatoxin B1 in food, characterized in that, Includes the following steps: Step S1: Prepare aluminum metal composite adsorbent material; Step S2: Adsorb and enrich aflatoxin B1 in high-moisture food samples using aluminum metal composite adsorbent material; Step S3: Separate the adsorbent from the food matrix using magnetic separation. Step S4: Elute the aflatoxin B1 on the adsorbent using an organic solvent; Step S5: Quantitatively detect aflatoxin B1 in the eluent.

2. The method for rapid detection of aflatoxin B1 in food according to claim 1, characterized in that: In step S1, the preparation of the aluminum metal composite adsorbent material includes the following sub-steps: Step S11: Load iron oxide nanoparticles onto an aluminum metal framework to obtain an aluminum metal composite carrier; Step S12: Mix maltitol with 3-aminopropyltriethoxysilane ethanol solution to modify the amino group in 3-aminopropyltriethoxysilane. Step S13: Immerse the aluminum metal composite carrier in the modified amino solution of step S12 to modify the surface of the aluminum metal composite carrier with modified amino.

3. The method for rapid detection of aflatoxin B1 in food according to claim 2, characterized in that: Step S11 includes the following sub-steps: Step S111: Select a porous aluminum alloy microplate with a pore size of 50-100μm as the aluminum metal skeleton; Step S112: Dissolve FeCl3·6H2O and FeCl2·4H2O in deionized water at a molar ratio of 2-3:1, add 25-30% ammonia water dropwise under nitrogen protection until the pH is 10-11, and react at 60-80℃ for 0.5-1h to generate Fe3O4 particles with a particle size of 50-100nm. Step S113: Disperse Fe3O4 particles in N,N-dimethylformamide, add an aluminum metal skeleton, and vacuum impregnate at 55-75℃ for 1-2.5h to form an aluminum metal composite carrier. Step S114: Dry the aluminum metal composite carrier at 60-75℃ for 10-12 hours, and then anneal the dried aluminum metal composite carrier at 300-350℃ for 0.5-1 hours.

4. The method for rapid detection of aflatoxin B1 in food according to claim 3, characterized in that: In step S113, Fe3O4 particles are dispersed in N,N-dimethylformamide to obtain a dispersion with a concentration of 3-5 mg / mL.

5. The method for rapid detection of aflatoxin B1 in food according to claim 2, characterized in that: In step S12, the concentration of the 3-aminopropyltriethoxysilane ethanol solution is 3-5%.

6. The method for rapid detection of aflatoxin B1 in food according to claim 2, characterized in that: Step S12 includes: Maltitol and 3-aminopropyltriethoxysilane ethanol solution are mixed at a mass ratio of 1-3:1, and the mixture is heated to 55-70℃ and stirred at 200-300 rpm for 1-2 hours. The stirred mixture was dried at 50-60℃ for 20-30 minutes to obtain a viscous crude product. The viscous crude product was washed with anhydrous diethyl ether to remove unreacted 3-aminopropyltriethoxysilane, and then dried under vacuum at 50-60°C for 10-12 h to obtain the modified amino group.

7. The method for rapid detection of aflatoxin B1 in food according to claim 2, characterized in that: Step S13 includes the following sub-steps: Step S131: Dissolve the modified amino group in anhydrous ethanol to prepare an impregnation solution with a concentration of 5-10%. Step S132: Clean the aluminum metal composite carrier with acetone by ultrasonic cleaning for 10-15 min, and then vacuum dry it at 70-80℃ for 1-1.5 h. Step S133: Immerse the aluminum metal composite carrier processed in step S132 into the impregnation solution, keep it at a constant temperature of 50-60℃, and stir at a speed of 200-300 rpm for 2-3 hours.

8. The method for rapid detection of aflatoxin B1 in food according to claim 7, characterized in that: In step S133, the mass ratio of the impregnation solution to the aluminum metal composite carrier is 20-25:

1.

9. The method for rapid detection of aflatoxin B1 in food according to claim 1, characterized in that: The modified amino groups of the aluminum metal composite adsorbent material bind to aflatoxin B1 in high-moisture food samples via hydrogen bonds. The organic solvent includes an acetonitrile-acetic acid solution, wherein the mass ratio of acetonitrile to acetic acid is 9-10:

1.

10. The method for rapid detection of aflatoxin B1 in food according to claim 1, characterized in that: The quantitative detection is performed using immunochromatographic test strips or high-performance liquid chromatography.