A modified hectorite and its preparation method and application, and a method for detecting mycotoxins in ghee

Abstract

The present invention belongs to the technical field of mycotoxin detection, and relates to a modified hectorite and its preparation method and application, and a method for detecting mycotoxins in ghee. The modified hectorite structure provided by the present invention contains a hectorite flaky two-dimensional nanostructure, an amide bond and an octadecyl group. The introduction of the octadecyl group can promote the modified hectorite to react with lipid interfering substances, and the hectorite flaky nanostructure enables it to have a strong physical adsorption capacity, which can adsorb small molecule interfering substances, and the presence of the amide bond is conducive to the combination of the modified hectorite with polar compounds. The modified hectorite provided by the present invention can be used as a purification material when the QuEChERS method is used to detect mycotoxins in ghee. The material can remove most of the impurities in the ghee acetonitrile extract when used alone, thereby achieving the purpose of purification.

Description

Technical Field

[0001] The invention belongs to the technical field of analytical chemistry and relates to a modified hectorite and a preparation method and application thereof, and a method for detecting mycotoxins in ghee. Background Art

[0002] Mycotoxins are a type of secondary metabolites produced by fungi such as Aspergillus and Fusarium. They have carcinogenic, teratogenic and mutagenic properties, and pose a serious threat to human and animal health. More than 400 types of mycotoxins have been discovered, among which aflatoxins, ochratoxins and alternaria toxins are the main mycotoxins that contaminate food.

[0003] Among many food safety testing methods, QuEChERS has attracted extensive attention from researchers due to its unique advantages in the pretreatment process. In this method, the reduction or elimination of matrix effects is mainly in the purification step, so the selection and use of purification materials are the most important factors determining the performance of the method. However, classic purification materials such as PSA, GCB and C 18 There are some problems in specific applications, especially when processing complex food matrix samples with high fat content and many highly polar substances, the purification effect is poor. Zirconium dioxide-based purification materials have shown certain advantages in removing lipid compounds, but have obvious deficiencies in removing impurities such as pigments, sugars, organic acids and phenols.

[0004] The extraction of target substances from complex high-fat matrices and the removal of interfering substances in the extract have always been a difficult problem in the field of agricultural product quality and safety testing. The application of new purification materials reported in the literature has promoted the development of the QuEChERS method. The development of new QuEChERS purification materials for high-fat foods is imperative. Summary of the invention

[0005] The purpose of the present invention is to provide a modified hectorite and a preparation method and application thereof, and a method for detecting mycotoxins in ghee. The modified hectorite provided by the present invention can be used as a purification material to quickly and accurately detect mycotoxins in ghee.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing modified hectorite, comprising the following steps:

[0008] The hectorite, amino-containing silane and the first organic solvent are mixed to carry out an amination reaction to obtain the aminated hectorite;

[0009] The aminated hectorite, stearic acid, a polypeptide condensation agent and a second organic solvent are mixed and subjected to an amidation reaction to obtain the modified hectorite.

[0010] Preferably, the amino-containing silane includes 3-aminopropyltriethoxysilane and / or 3-aminopropyltrimethoxysilane; the first organic solvent is toluene;

[0011] The usage ratio of the hectorite and the amino-containing silane is 0.1-0.2 g:0.5 mL; the usage ratio of the hectorite and the first organic solvent is 0.1-0.2 g:45 mL;

[0012] The temperature of the amination reaction is 110° C.; the time of the amination reaction is 24 h; the amination reaction is carried out under stirring, and the stirring speed is 50 rpm.

[0013] Preferably, the polypeptide condensation reagent is 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate; the second organic solvent is acetonitrile;

[0014] The mass ratio of the amido lithium saponite to stearic acid is 1:0.1; the mass ratio of the amido lithium saponite to the polypeptide condensation reagent is 1:0.1; and the dosage ratio of the amido lithium saponite to the second organic solvent is 1 g:10 mL.

[0015] Preferably, the mixing of the amidated lithium laponite, stearic acid, a polypeptide condensation agent and a second organic solvent comprises:

[0016] After ultrasonically mixing stearic acid and a second organic solvent, a polypeptide condensation reagent is added and shaken to obtain a precursor solution; the precursor solution is mixed with aminated lithium laponite;

[0017] The ultrasonic mixing time is 5 min;

[0018] The oscillation was carried out under a sealed condition; the temperature of the oscillation was 30° C. and the time was 30 min.

[0019] Preferably, the amidation reaction is carried out at a temperature of 30° C. and for 3 hours; and the amidation reaction is carried out under sealing and shaking conditions.

[0020] The present invention also provides modified hectorite prepared by the preparation method described in the above technical solution.

[0021] The present invention also provides the use of the modified hectorite described in the above technical solution as a purification material in detecting mycotoxins in ghee.

[0022] Preferably, the fungal toxins include one or more of vomitoxin, aflatoxin G2, aflatoxin G1, aflatoxin B2, aflatoxin B1, alternariae, ochratoxin A, alternariae spores, tenegrin and T-2 toxin.

[0023] The present invention also provides a method for detecting mycotoxins in ghee, which adopts the QuEChERS method for detection, comprising the following steps:

[0024] Step 1: Mix ghee, sodium chloride, anhydrous magnesium sulfate, acidified acetonitrile and water, and heat and melt them to obtain a melting system;

[0025] Step 2: shaking and centrifuging the melted system in sequence, and collecting the acetonitrile extract on the upper layer;

[0026] Step 3: mixing and shaking the acetonitrile extract and anhydrous magnesium sulfate, and collecting the supernatant after standing;

[0027] Step 4: After mixing and oscillating the supernatant and the purification material, filtering to obtain a test solution; the purification material is the modified hectorite described in the above technical solution;

[0028] Step 5: The test solution is subjected to ultra-high performance liquid chromatography tandem mass spectrometry analysis.

[0029] Preferably, the detection conditions of the ultra-high performance liquid chromatography include: the column temperature is 40°C, the flow rate is 0.25 mL / min; the sample volume of the injection solution is 2.0 μL; the mobile phase A is 2 mmol / L ammonium acetate solution, and the mobile phase B is acetonitrile containing 0.1% formic acid; the elution mode is gradient elution;

[0030] The procedure of the gradient elution is:

[0031] 0-2min: the volume percentage of the mobile phase A is 70%;

[0032] 2-5min: the volume percentage of the mobile phase A increases uniformly from 70% to 90%;

[0033] 5-7min: the volume percentage of the mobile phase A is 90%;

[0034] 7-7.5min: the volume percentage of the mobile phase A is uniformly reduced from 90% to 30%;

[0035] 7.5-16min: the volume percentage of the mobile phase A is 30%;

[0036] The conditions for mass spectrometry detection include: the ionization mode of the ion source is electrospray ionization, positive ion mode and negative ion mode, the mass spectrometry scanning mode is full scan mode and multiple reaction monitoring; in the positive ion mode, the spray needle voltage is 5.5 kV; in the negative ion mode, the spray needle voltage is -4.5 kV; the nebulizer gas pressure is 55 psi, and the auxiliary gas pressure is 25 psi.

[0037] The present invention provides a method for preparing a modified hectorite, comprising the following steps: mixing hectorite, amino-containing silane and a first organic solvent, performing an amination reaction, and obtaining an amidated hectorite; mixing the amidated hectorite, stearic acid, a polypeptide condensation reagent and a second organic solvent, and performing an amidation reaction, and obtaining the modified hectorite. The modified hectorite structure obtained by the preparation method provided by the present invention contains a hectorite flaky two-dimensional nanostructure, an amide bond and an octadecyl group. The introduction of the octadecyl group can promote the modified hectorite to react with lipid interfering substances, the hectorite flaky nanostructure enables it to have a strong physical adsorption capacity, and can adsorb small molecule interfering substances, and the presence of the amide bond is conducive to the combination of the modified hectorite with polar compounds. The modified hectorite provided by the present invention is used as a purification material in the detection of food safety by the QuEChERS method, and the material can remove most of the impurities in the ghee acetonitrile extract when used alone, thereby achieving the purpose of purification.

[0038] The present invention also provides a method for detecting fungal toxins in ghee, which is detected by the QuEChERS method, and comprises the following steps: step 1: mixing ghee, sodium chloride, anhydrous magnesium sulfate, acidified acetonitrile and water, heating and melting to obtain a melting system; step 2: sequentially oscillating and centrifuging the melting system, and collecting the upper acetonitrile extract; step 3: mixing and oscillating the acetonitrile extract and anhydrous magnesium sulfate, and collecting the upper clear liquid; step 4: mixing and oscillating the upper clear liquid and a purification material, filtering the obtained upper liquid to obtain a detection liquid; step 5: performing ultra-high performance liquid chromatography tandem mass spectrometry detection and analysis on the detection liquid. The present invention uses modified hectorite as a purification material for detecting fungal toxins in ghee by the QuEChERS method, and the material can be used alone as a purification material to remove most of the impurities in the ghee acetonitrile extract, thereby achieving the purpose of purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic flow chart of a method for preparing the modified hectorite provided by the present invention;

[0040] Figure 2 The modified hectorite obtained in Example 1 of the present invention is a purification effect diagram in the mass spectrometer in positive ion mode, wherein curve A is a total ion current diagram of a blank ghee extract in full scan mode, and curve B is a total ion current diagram of a blank ghee sample after purification by the modified hectorite in full scan mode;

[0041] Figure 3 The figure is a purification effect diagram of the modified hectorite obtained in Example 1 of the present invention in the negative ion mode of the mass spectrometer, wherein curve A is the total ion current diagram of the blank ghee extract in the full scan mode, and curve B is the total ion current diagram of the blank ghee sample after purification by the modified hectorite in the full scan mode. DETAILED DESCRIPTION

[0042] The present invention provides a method for preparing modified hectorite, comprising the following steps:

[0043] The hectorite, amino-containing silane and the first organic solvent are mixed to carry out an amination reaction to obtain the aminated hectorite;

[0044] The aminated hectorite, stearic acid, a polypeptide condensation agent and a second organic solvent are mixed and subjected to an amidation reaction to obtain the modified hectorite.

[0045] In the present invention, unless otherwise specified, all raw materials are commercially available products well known to those skilled in the art.

[0046] The invention mixes hectorite, amino-containing silane and a first organic solvent, and performs an amination reaction to obtain aminated hectorite.

[0047] In the present invention, the hectorite is preferably prepared by a hydrothermal method. The present invention has no special limitation on the process of preparing the hectorite by the hydrothermal method, and a method well known to those skilled in the art can be used.

[0048] In the present invention, the amino-containing silane is preferably 3-aminopropyltriethoxysilane and / or 3-aminopropyltrimethoxysilane; and the first organic solvent is preferably toluene.

[0049] In the present invention, the usage ratio of the hectorite and the aminosilane is preferably 0.1-0.2 g:5 mL, and more preferably 0.2 g:5 mL; the usage ratio of the hectorite and the first organic solvent is preferably 0.1-0.2 g:45 mL, and more preferably 0.2 g:45 mL.

[0050] In the present invention, the mixing method preferably includes ultrasonic mixing. The present invention has no special limitation on the ultrasonic mixing process, and a method well known to those skilled in the art can be used. In the present invention, the amination reaction is preferably carried out in a three-necked flask.

[0051] In the present invention, the temperature of the amination reaction is preferably 110°C; the time of the amination reaction is preferably 24 hours; the amination reaction is preferably carried out under reflux conditions. In the present invention, the amination reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 50 rpm. In the present invention, the amination reaction is preferably carried out using a magnetic stirring oil bath to heat and stir the reaction container.

[0052] After the amination reaction, the present invention also preferably includes washing and drying the product of the amination reaction; the washing preferably includes washing with acetone and acetonitrile alternately; the number of washings with acetone and acetonitrile alternately is preferably 5 times; the drying temperature is preferably 30 to 60° C., more preferably 60° C.; the drying time is preferably 6 hours; and the drying is preferably carried out in a vacuum drying oven.

[0053] After obtaining the aminated hectorite, the present invention mixes the aminated hectorite, stearic acid, a polypeptide condensation agent and a second organic solvent to carry out an amidation reaction to obtain the modified hectorite.

[0054] In the present invention, the polypeptide condensation reagent is preferably 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate; and the second organic solvent is preferably acetonitrile.

[0055] In the present invention, the mass ratio of the amido lithium saponite to stearic acid is preferably 1:0.1; the mass ratio of the amido lithium saponite to the polypeptide condensation reagent is preferably 1:0.1; and the dosage ratio of the amido lithium saponite to the second organic solvent is preferably 1 g:10 mL.

[0056] In the present invention, the mixing of the lithium amide saponite, stearic acid, a polypeptide condensation reagent and a second organic solvent preferably comprises: ultrasonically mixing the stearic acid and the second organic solvent, adding the polypeptide condensation reagent and oscillating to obtain a precursor solution; and mixing the precursor solution with lithium amide saponite.

[0057] In the present invention, the ultrasonic mixing time is preferably 5 minutes. In the present invention, the oscillation is preferably carried out under a sealed condition; the oscillation temperature is preferably 30° C., and the oscillation time is preferably 30 minutes. In the present invention, the carboxyl group can be fully converted into an active ester during the oscillation process.

[0058] In the present invention, the temperature of the amidation reaction is preferably 30° C., and the time is preferably 3 h; the amidation reaction is preferably carried out under sealing and shaking conditions.

[0059] After the amidation reaction, the present invention also preferably includes washing and drying the product of the amidation reaction; the washing preferably includes washing with acetonitrile and ethanol alternately; the number of washings with acetonitrile and ethanol alternately is preferably 5 times; the drying temperature is preferably 60°C; the drying time is preferably 6 hours; and the drying is preferably carried out in a vacuum drying oven.

[0060] The present invention also provides modified hectorite prepared by the preparation method described in the above technical solution.

[0061] In the present invention, the modified hectorite preferably contains a hectorite flaky two-dimensional nanostructure, an amide bond, and an octadecyl group. In the present invention, the hectorite flaky nanostructure enables it to have a strong physical adsorption capacity and can adsorb small molecule interfering substances; the amide bond is conducive to the combination of the modified hectorite and polar compounds; the introduction of the octadecyl group can enhance the interaction between the purification material and lipid interfering substances.

[0062] The present invention also provides the use of the modified hectorite described in the above technical solution as a purification material in detecting mycotoxins in ghee.

[0063] In the present invention, the fungal toxins preferably include one or more of vomitoxin, aflatoxin G2, aflatoxin G1, aflatoxin B2, aflatoxin B1, alternariae, ochratoxin A, alternariae spores, tenegrin and T-2 toxin.

[0064] The present invention also provides a method for detecting mycotoxins in ghee, which adopts the QuEChERS method for detection, comprising the following steps:

[0065] Step 1: Mix ghee, sodium chloride, anhydrous magnesium sulfate, acidified acetonitrile and water, and heat and melt them to obtain a melting system;

[0066] Step 2: shaking and centrifuging the melted system in sequence, and collecting the acetonitrile extract on the upper layer;

[0067] Step 3: mixing and shaking the acetonitrile extract and anhydrous magnesium sulfate, and collecting the supernatant after standing;

[0068] Step 4: After the supernatant and the purification material are mixed and shaken, the obtained supernatant is filtered to obtain a test liquid; the purification material is the modified hectorite described in the above technical solution;

[0069] Step 5: The test solution is subjected to ultra-high performance liquid chromatography tandem mass spectrometry analysis.

[0070] In the present invention, in step 1, the usage ratio of the ghee, sodium chloride, anhydrous magnesium sulfate, acidified acetonitrile and water is preferably 2.5g:1g:1g:10mL:2.5mL; the temperature of the heating and melting is preferably 40°C; and the melting system preferably includes a fully melted state or a semi-melted state.

[0071] In the present invention, in step 2, the oscillation time is preferably 1 min; the centrifugal speed is preferably 5000 r / min; and the centrifugal time is preferably 3 min.

[0072] In the present invention, in step 3, the mixing and oscillating time is preferably 1 min.

[0073] In the present invention, the usage ratio of the supernatant and the purification material is preferably 1 mL:50 mg; the mixing and oscillation time is preferably 2 min; and the filtration is preferably performed using an organic filter membrane with a pore size of 0.22 μm.

[0074] In the present invention, the detection conditions of the ultra-high performance liquid chromatography preferably include: the chromatographic column temperature is 40°C, the flow rate is 0.25 mL / min; the sample volume of the injection solution is 2.0 μL; the mobile phase A is 2 mmol / L ammonium acetate solution, and the mobile phase B is acetonitrile containing 0.1% formic acid; and the elution method is gradient elution.

[0075] In the present invention, the procedure of the gradient elution is preferably:

[0076] 0-2min: the volume percentage of the mobile phase A is 70%;

[0077] 2-5min: the volume percentage of the mobile phase A increases uniformly from 70% to 90%;

[0078] 5-7min: the volume percentage of the mobile phase A is 90%;

[0079] 7-7.5min: the volume percentage of the mobile phase A is uniformly reduced from 90% to 30%;

[0080] 7.5-16min: the volume percentage of the mobile phase A is 30%.

[0081] In the present invention, the conditions for mass spectrometry detection preferably include: the ion source ionization mode is electrospray ionization, positive ion mode and negative ion mode, the mass spectrometry scanning mode is full scan mode and multiple reaction monitoring; in positive ion mode, the spray needle voltage is 5.5 kV; in negative ion mode, the spray needle voltage is -4.5 kV; the nebulizing gas pressure is 55 psi, and the auxiliary gas pressure is 25 psi.

[0082] In the present invention, the ion parameters of 10 fungal toxins are shown in Table 1.

[0083] Table 1 Retention time, qualitative and quantitative ions of mycotoxin target compounds

[0084]

[0085] In order to further illustrate the present invention, a modified hectorite provided by the present invention, a preparation method and application thereof, and a method for detecting fungal toxins in ghee are described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0086] Example 1

[0087] Schematic diagram of the preparation process of modified hectorite Figure 1 As shown, specifically:

[0088] 0.2 g of laponite powder, 5 mL of 3-aminopropyltriethoxysilane and 45 mL of toluene were transferred to a 250 mL three-necked flask after ultrasonic mixing for amination reaction. The three-necked flask was heated to 110°C in a magnetic stirring oil bath and refluxed for 24 h, during which magnetic stirring was maintained at a stirring rate of 50 rpm.

[0089] The amination reaction product was washed alternately with acetone and acetonitrile to obtain aminated lithium laponite powder, which was dried in a vacuum drying oven at 60° C. for 6 h and then used for later use.

[0090] 100 mg of stearic acid and 10 mL of acetonitrile were added to a 25 mL polytetrafluoroethylene centrifuge tube with a cap, and the mixture was uniformly mixed by ultrasonication for 5 min. Then 100 mg of 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU) was added, and the tube was sealed and shaken at 30°C for 30 min to fully convert the carboxyl group into an active ester.

[0091] Add 1 g of the previously prepared amino lithium laponite powder, seal again and oscillate the reaction at 30°C for 3 hours. After the reaction, the solid product is thoroughly washed alternately with acetonitrile and ethanol, and dried in a vacuum drying oven at 60°C for 6 hours. The obtained solid product is the modified lithium laponite (octadecyl bonded lithium laponite).

[0092] Application Example 1

[0093] The modified hectorite prepared in Example 1 was used as the purification material, and the QuEChERS method was used to detect 10 fungal toxins in ghee.

[0094] 2.5 g of ghee, 2.5 mL of water, 1 g of sodium chloride, 1 g of anhydrous magnesium sulfate and 10 mL of acidified acetonitrile were added to a 25 mL plastic centrifuge tube with a cap, mixed evenly, and heated to 40° C. to melt to obtain a melted system in a semi-melted state.

[0095] The melted system was shaken vigorously for 1 min and then centrifuged at a speed of 5000 r / min for 3 min to collect the upper acetonitrile extract.

[0096] The upper acetonitrile extract was placed in a 20 mL plastic centrifuge tube containing 1 g of anhydrous magnesium sulfate, mixed and shaken for 1 min, and allowed to stand until the anhydrous magnesium sulfate naturally settled, and 1 mL of the upper clear liquid was collected.

[0097] The collected supernatant was placed in a 5 mL plastic centrifuge tube containing 50 mg of modified hectorite purification adsorbent. After oscillation for 2 minutes, all the solid-liquid mixture was drawn up with a 1 mL disposable sterile syringe and filtered through a 0.22 μm organic filter membrane to obtain the test solution.

[0098] The test solution was placed in a sample injection bottle and analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry.

[0099] The detection conditions of ultra-high performance liquid chromatography include: the column temperature is set to 40°C, the flow rate is 0.25mL / min. The sample volume of the injection solution is 2.0μL. The mobile phase A is 2mmol / L ammonium acetate solution, and the mobile phase B is acetonitrile (containing 0.1% formic acid). The elution mode is gradient elution;

[0100] The procedure of the gradient elution is shown in Table 2.

[0101] Table 2 Mobile phase gradient elution conditions

[0102] T / min A / ％ B / ％ 0.00 70 30 0.20 70 30 5.00 90 10 7.00 90 10 7.50 30 70 16.00 30 70

[0103] The conditions for mass spectrometry detection include: the ion source ionization mode is electrospray ionization, positive ion mode and negative ion mode, and the mass spectrometry scanning mode is full scan mode and multiple reaction monitoring (MRM). In the positive ion mode, the spray needle voltage is 5.5 kV; in the negative ion mode, the spray needle voltage is -4.5 kV. The nebulizer gas pressure is 55 psi and the auxiliary gas pressure is 25 psi. The ion parameters of the 10 fungal toxins are shown in Table 1.

[0104] Figure 2 The modified hectorite obtained in Example 1 of the present invention is a purification effect diagram in the mass spectrometer in positive ion mode, wherein curve A is a total ion current diagram of a blank ghee extract in full scan mode, and curve B is a total ion current diagram of a blank ghee sample after purification by the modified hectorite in full scan mode; Figure 3 The figure is a purification effect diagram of the modified hectorite obtained in Example 1 of the present invention in the negative ion mode of the mass spectrometer, wherein curve A is the total ion current diagram of the blank ghee extract in the full scan mode, and curve B is the total ion current diagram of the blank ghee sample after purification by the modified hectorite in the full scan mode.

[0105] According to the sample pretreatment method established by the present invention, a series of samples with different standard levels were treated. By adding 1.0μg / kg to 500μg / kg of 10 target mycotoxins to blank ghee samples, the working curves of the quantitative ion peak area Y and the corresponding target concentration X (μg / kg) of the 10 mycotoxins were calculated. The detection limit and the quantitative limit were calculated according to the signal-to-noise ratio, and their values ​​were 3 times and 10 times the signal-to-noise ratio, respectively. As shown in Table 3, all targets have good linear responses, and the correlation coefficient values ​​are 0.9900 to 9991. The detection limit ranges from 0.10μg / kg to 18.62μg / kg, and the quantitative limit ranges from 0.32μg / kg to 62.07μg / kg.

[0106] Table 3 Standard curve equation, linear range, correlation coefficient, detection limit and quantification limit of mycotoxins

[0107]

[0108]

[0109] In order to evaluate the validation of the proposed method, three different quality control levels (10 μg / kg, 100 μg / kg and 500 μg / kg) were added to blank ghee samples without detected pesticide residues for recovery experiments, among which the lowest added concentration of vomitoxin was 65 μg / kg. Six replicates were made for each sample, and the average recovery rate and relative standard deviation were calculated. The recovery rate and relative standard deviation data of each pesticide are shown in Table 4.

[0110] Table 4 Recovery and relative standard deviation of target mycotoxins

[0111]

[0112]

[0113] It can be seen from Tables 3 and 4 that the modified hectorite prepared in Example 1 of the present invention is used as the QuEChERS purification material to detect mycotoxins in ghee. Under the three conditions of low, medium and high spike addition, the spiked recoveries of 10 mycotoxins are 72.2-113.9%, the relative standard deviation ranges from 3.2 to 17.5% (all <20%), the detection limit ranges from 0.10 to 18.62 μg / kg, and the quantification limit ranges from 0.32 to 62.07 μg / kg, indicating that the modified hectorite of the present invention is used as the QuEChERS purification material to quickly and accurately detect mycotoxins in ghee.

[0114] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. The application of modified hectorite as a purification material in detecting mycotoxins in ghee, characterized in that: The preparation method of the modified hectorite comprises the following steps: The hectorite, amino-containing silane and the first organic solvent are mixed to carry out an amination reaction to obtain the aminated hectorite; The aminated hectorite, stearic acid, a polypeptide condensation agent and a second organic solvent are mixed and subjected to an amidation reaction to obtain the modified hectorite.

2. The use according to claim 1, characterized in that: The amino-containing silane includes 3-aminopropyltriethoxysilane and / or 3-aminopropyltrimethoxysilane; the first organic solvent is toluene; The usage ratio of the hectorite and the amino-containing silane is 0.1-0.2 g: 0.5 mL; the usage ratio of the hectorite and the first organic solvent is 0.1-0.2 g: 45 mL; The temperature of the amination reaction is 110° C.; the time of the amination reaction is 24 h; the amination reaction is carried out under stirring, and the stirring speed is 50 rpm.

3. The use according to claim 1, characterized in that: The polypeptide condensation reagent is 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate; the second organic solvent is acetonitrile; The mass ratio of the amido lithium saponite to stearic acid is 1:0.1; the mass ratio of the amido lithium saponite to the polypeptide condensation reagent is 1:0.1; and the dosage ratio of the amido lithium saponite to the second organic solvent is 1 g:10 mL.

4. The use according to claim 1 or 3, characterized in that: The mixing of the aminated lithium laponite, stearic acid, a polypeptide condensation agent and a second organic solvent comprises: After ultrasonically mixing stearic acid and a second organic solvent, a polypeptide condensation reagent is added and shaken to obtain a precursor solution; the precursor solution is mixed with aminated lithium laponite; The ultrasonic mixing time is 5 min; The oscillation was carried out under a sealed condition; the temperature of the oscillation was 30° C. and the time was 30 min.

5. The use according to claim 4, characterized in that: The amidation reaction was carried out at a temperature of 30° C. and for 3 hours; the amidation reaction was carried out under sealing and shaking conditions.

6. The use according to claim 1, characterized in that: The fungal toxins include one or more of vomitoxin, aflatoxin G2, aflatoxin G1, aflatoxin B2, aflatoxin B1, alternariae, ochratoxin A, alternariae spores, tenegrin and T-2 toxin.

7. A method for detecting mycotoxins in ghee, characterized in that: The QuEChERS method was used for detection, including the following steps: Step 1: Mix ghee, sodium chloride, anhydrous magnesium sulfate, acidified acetonitrile and water, and heat and melt them to obtain a melting system; Step 2: shaking and centrifuging the melted system in sequence, and collecting the acetonitrile extract on the upper layer; Step 3: mixing and shaking the acetonitrile extract and anhydrous magnesium sulfate, and collecting the supernatant after standing; Step 4: After mixing and oscillating the supernatant and the purification material, filtering to obtain a test solution; the purification material is the modified hectorite in the application according to any one of claims 1 to 6; Step 5: The test solution is subjected to ultra-high performance liquid chromatography tandem mass spectrometry analysis.

8. The detection method according to claim 7, characterized in that: The detection conditions of the ultra-high performance liquid chromatography include: the column temperature is 40°C, the flow rate is 0.25mL / min; the sample volume of the injection solution is 2.0μL; the mobile phase A is 2mmol / L ammonium acetate solution, and the mobile phase B is acetonitrile containing 0.1% formic acid; the elution method is gradient elution; The procedure of the gradient elution is: 0~2min: the volume percentage of the mobile phase A is 70%; 2-5min: the volume percentage of the mobile phase A increases uniformly from 70% to 90%; 5-7min: the volume percentage of the mobile phase A is 90%; 7-7.5min: the volume percentage of the mobile phase A is uniformly reduced from 90% to 30%; 7.5-16min: the volume percentage of the mobile phase A is 30%; The conditions for mass spectrometry detection include: the ion source ionization modes are electrospray ionization positive ion mode and electrospray ionization negative ion mode, the mass spectrometry scanning modes are full scan mode and multiple reaction monitoring; in the positive ion mode, the spray needle voltage is 5.5 kV; in the negative ion mode, the spray needle voltage is -4.5 kV; the nebulizer gas pressure is 55 psi, and the auxiliary gas pressure is 25 psi.

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