A method for separating a plurality of synthetic antioxidants from edible fats and oils

Abstract

The present application relates to the technical field of detection, in particular to a method for separating multiple synthetic antioxidants from edible oil and fat. The method for separating multiple synthetic antioxidants from edible oil and fat provided by the present application uses solid-supported high-surface-area double liquid layer permeation extraction technology to quickly and efficiently separate, extract and purify multiple synthetic antioxidants in edible oil and fat, and obtain a solution containing multiple synthetic antioxidants. The solution can be used for detecting the content of the synthetic antioxidants by multiple chemical analysis technologies after being concentrated or not concentrated, or can be used for detecting the synthetic antioxidants by immunological analysis technology after being diluted with water. The method is simple and efficient, can simultaneously pretreat multiple samples, uses less organic solvent, is safe and environmentally friendly, has high recovery rate, and has good stability. The recovery rate of various synthetic antioxidants is generally between 80% and 100%, and the repeatability RSD of the recovery rate of each synthetic antioxidant is less than 5%.

Description

A method for isolating multiple synthetic antioxidants from edible oils Technical Field

[0001] This invention relates to the field of detection technology, and in particular to a method for separating multiple synthetic antioxidants from edible oils. Background Technology

[0002] Synthetic antioxidants are a class of compounds that are artificially synthesized or semi-synthesized and have antioxidant properties. They exhibit a good effect in slowing down the oxidation and deterioration of various edible oils (including oils in oily foods). Therefore, they are mainly added to various edible animal and vegetable oils, oil products (such as margarine, shortening, etc.) and oily foods (such as nut and seed products, fried noodle products, instant rice and noodle products, mooncakes, biscuits, baked foods, cured meat products, dried aquatic products, puffed foods, etc.) to extend the shelf life of these types of foods. Currently, the most common synthetic antioxidants used in food both domestically and internationally include tert-butylhydroquinone (TBHQ), propyl gallate (PG), octyl gallate (OG), dodecyl gallate (DG), 2,6-di-tert-butyl-4-hydroxymethylphenol (Ionox-100), 4-hexylresorcinol (4-HR), amyl gallate (IAG), 2,4,5-trihydroxyphenylbutanone (THBP), nordihydroguaiacol (NDGA), tert-butylhydroanisole (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT), and ethoxyquinoline (EQ). According to the relevant provisions of the National Food Safety Standard for the Use of Food Additives (GB 2760-2014), the limits for the addition of various antioxidants in the above-mentioned foods are "based on oil content". That is, except for various edible animal and vegetable oils, oil products and various oil-containing foods must first extract the oil components, and then use the extracted pure oil as the test object to determine whether the content of synthetic antioxidants exceeds the standard. Therefore, regardless of the type of food, the final test is the determination of the content of phenolic synthetic antioxidants in edible oils.

[0003] Currently, the detection of phenolic synthetic antioxidants in various foods in my country is mainly based on existing national food safety standards such as "Determination of Nine Antioxidants in Food" (GB 5009.32-2016), "Determination of Antioxidants in Exported Oils by High Performance Liquid Chromatography" (SN / T 1050-2014), and "Determination of Multiple Antioxidants in Exported Foods" (SN / T 3849-2014). These standards primarily employ high performance liquid chromatography (HPLC) to simultaneously separate and determine multiple synthetic antioxidants in food. Furthermore, they all utilize reversed-phase HPLC, employing a non-polar reversed-phase C18 liquid chromatographic column as the stationary phase and polar solvents, such as methanol or acetonitrile, mixed with water in varying proportions as the mobile phase. Gradient elution techniques are also used to achieve the separation and determination of multiple synthetic antioxidants. A key prerequisite for this detection technology is that appropriate sample pretreatment techniques must first be used to separate and extract these various synthetic antioxidants from the oils, and the extracts must be thoroughly purified to minimize the amount of residual oil. This is because the main components of various natural edible oils—glycerol fatty acid esters—have a strong adsorption and contamination effect on C18 liquid chromatography columns under reversed-phase liquid chromatography conditions. This not only clogs the column and greatly shortens its lifespan, but also has a severely adverse impact on the lifespan of the high-performance liquid chromatograph (HPLC).

[0004] Traditional techniques for separating, extracting, and purifying various synthetic antioxidants from edible oils mainly fall into three categories: 1) Multiple liquid-liquid extraction: This technique uses polar solvents such as methanol and ethanol as extractants. Synthetic antioxidants are continuously extracted from a hexane solution (a non-polar solution) of the oil through multiple manual liquid-liquid extraction operations. The polar extractants obtained from each liquid-liquid extraction are combined to form the extract. Finally, the solvent in the extract is concentrated and evaporated, followed by HPLC analysis. This technique has the following main drawbacks: It is cumbersome and time-consuming due to the purely manual operation; the recovery rate fluctuates significantly due to the manual operation, resulting in poor repeatability and reproducibility of the detection results; a large amount of oily impurities are co-extracted, leading to poor purification and significant contamination of the C18 HPLC column; the consumption of organic solvents is high, making it uneconomical and environmentally unfriendly; and the need for concentration and evaporation of large amounts of organic solvents raises safety concerns. (ii) Multiple liquid-liquid extraction + C18 solid-phase extraction purification technology: After multiple liquid-liquid extractions, all extracts are passed through a C18 solid-phase extraction column, and the column is further eluted with extractant. All column eluents are combined, concentrated, and the solvent is evaporated to dryness before HPLC analysis. While this technique solves the problem of co-extraction of large amounts of oily impurities and contamination of the C18 HPLC column during multiple liquid-liquid extractions, the manual operation is more complex, cumbersome, time-consuming, and labor-intensive. Furthermore, the consumption of organic solvents increases, as does the amount of organic solvent evaporated during concentration. (III) Preparative Gel Permeation Chromatography (GPC): This technique utilizes the molecular weight sieving effect of preparative gel permeation chromatography columns, specifically the significant molecular weight difference between synthetic antioxidants and oils. Through gel permeation chromatography, synthetic antioxidants are extracted from oils. While this technology can achieve complete separation and extraction of synthetic antioxidants from oils, and can be performed using fully or semi-automated preparative gel permeation chromatography instruments, greatly reducing manual labor, it still has the following drawbacks: It requires expensive specialized equipment—preparative gel permeation chromatography instruments; high cost: it requires expensive specialized consumables—preparative gel permeation chromatography columns, and these columns have a very short lifespan, becoming unusable after only 2-3 months; low pretreatment efficiency: each sample pretreatment operation can only process one sample, and although the instrument achieves fully or semi-automatic operation, each sample pretreatment takes about one hour, resulting in extremely low efficiency; the consumption of organic solvents during pretreatment is very large, typically consuming more than 100 mL of organic solvent per pretreatment; and a relatively large amount of organic solvent still needs to be concentrated and evaporated, leading to poor safety. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for separating multiple synthetic antioxidants from edible oils. This method employs a solid-phase supported, high-surface-area double-layer permeation extraction technique to rapidly and efficiently separate, extract, and purify multiple synthetic antioxidants from edible oils, obtaining a solution containing multiple extracted synthetic antioxidants. This solution can be concentrated or not for use in various chemical analysis techniques (such as high-performance liquid chromatography, gas chromatography, high-performance liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, etc.) to detect the content of these synthetic antioxidants. Alternatively, it can be diluted with water for use in immunological analysis techniques (such as ELSA, colloidal gold immunochromatography, etc.) to detect these synthetic antioxidants.

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

[0007] The first aspect of this invention provides a method for separating multiple synthetic antioxidants from edible oils, the specific technical solution of which is as follows:

[0008] The first aspect of this invention provides a method for separating various synthetic antioxidants from edible oils, comprising the following steps:

[0009] Step 1: Dissolve and dilute the grease sample with grease sample dissolving solution to form a grease sample solution;

[0010] Step 2: Mix the oil sample solution obtained in Step 1 with the solid extraction adsorbent, then add the extraction solution for mixing and extraction to obtain the reaction mixture;

[0011] Step 3: Centrifuge. The reaction mixture will separate into three layers. Take the top layer solution and add a QuEChERS (matrix dispersion solid phase extraction) purification tube containing a purification adsorbent to purify it, thus obtaining a solution containing a variety of synthetic antioxidants.

[0012] The oil sample dissolving solution includes solvent A and solvent B; solvent A is an organic solvent, miscible with the extract, and the solubility of the oil sample in solvent A is ≥2.0 g / 100 g solvent A; solvent B is an organic solvent, miscible with the extract and solvent A, and the solubility of the synthetic antioxidant in solvent B is ≥0.10 g / 100 g solvent B. For oil samples that are liquid at room temperature, solvent B is immiscible with the oil sample; for oil samples that are solid at room temperature, solvent B may or may not be miscible with the oil sample; the solubility of the synthetic antioxidant in the extract is ≥0.10 g / 100 g extract, and the solubility of the oil sample is ≤1.0 g / 100 g extract.

[0013] In some embodiments of the present invention, for edible oils that are liquid at room temperature, the volume of solvent B accounts for 20% to 50% of the total volume of the oil sample solution, preferably 30% to 40%; for edible oils that are solid at room temperature, the volume of solvent B accounts for 30% to 70% of the total volume of the oil sample solution, preferably 40% to 60%.

[0014] In some embodiments of the present invention, the volume ratio of the oil sample solution to the oil sample is 2 to 20:1.

[0015] In some embodiments of the present invention, the volume ratio of the extract to the oil sample is 2 to 10:1.

[0016] In some embodiments of the present invention, the solid adsorbent is silica particles, wherein the silica content is greater than 99.5%; preferably, the silica particles are natural, rough-surfaced fine sand; preferably, the silica particles have a mesh size of 20 to 160.

[0017] In some embodiments of the present invention, the purification adsorbent is a C18 (end-capped) adsorbent.

[0018] In some embodiments of the present invention, for edible oils that are liquid at room temperature, solvent A is selected from one or more of chlorinated hydrocarbon solvents, ester solvents, or ether solvents; preferably, solvent A is selected from one or more of dichloromethane, trichloromethane, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl propionate, ethyl propionate, butyl propionate, amyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, amyl butyrate, diethyl ether, propyl ether, isopropyl ether, methyl butyl ether, and tetrahydrofuran; solvent B is selected from one or more of methanol, ethanol, acetonitrile, and propionitrile.

[0019] In some embodiments of the present invention, solvent A is selected from one or more of dichloromethane, trichloromethane, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl propionate, ethyl propionate, butyl propionate, amyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, amyl butyrate, diethyl ether, propyl ether, isopropyl ether, methyl butyl ether, tetrahydrofuran, benzene, toluene, xylene, and trimethylbenzene; solvent B is selected from one or more of aromatic hydrocarbon solvents and acetonitrile; preferably, solvent B is selected from one or more of benzene, toluene, xylene, trimethylbenzene, and acetonitrile, and solvent B does not contain the same components as solvent A.

[0020] In some embodiments of the present invention, the extract is selected from one or more of methanol, ethanol, acetonitrile, N,N-dimethylformamide, N,N-diethylformamide, and N,N-dimethylacetamide.

[0021] In some embodiments of the present invention, the extract contains acetic acid or formic acid; preferably, the volume fraction of the acetic acid or formic acid is 0.05% to 2%.

[0022] In some embodiments of the present invention, the extract contains thioctic acid or sesamol; preferably, the proportion of thioctic acid is 0.01wt% to 0.10wt%; or the proportion of sesamol is 0.1wt% to 0.5wt%.

[0023] In some embodiments of the present invention, in order to ensure that the oil sample solution is fully dispersed and coated on the solid phase particle surface of the solid extraction adsorbent in step two, two conditions need to be met: 1) the volume of the oil sample solution added to each 10g of the solid extraction adsorbent is 1.0 to 4.0mL; 2) after the oil sample solution is added to the solid extraction adsorbent, it is allowed to stand at room temperature for a time of 3 minutes or more.

[0024] In some embodiments of the present invention, the mixing and extraction in step two is carried out by vortex oscillation, specifically by vortex oscillation at 2000-3500 rpm for 30-120 seconds to fully mix and react.

[0025] In some embodiments of the present invention, the centrifugation in step three is high-speed centrifugation with a rotation speed of 4000 to 10000 rpm.

[0026] In some embodiments of the present invention, the purification process in step three is carried out by vortex oscillation, specifically by vortex oscillation at 2000-3000 rpm for 1-5 minutes to fully mix and react.

[0027] In some preferred embodiments of the present invention, the oil sample solution and the extract satisfy the following relationship: the volume percentage of solvent A in the oil sample solution used for a single extraction is 30% to 5% of the total volume of the oil sample solution and the extract used.

[0028] A second aspect of the present invention provides the application of the above-described method for separating multiple synthetic antioxidants from edible oils in the detection of antioxidant content in edible oils.

[0029] A third aspect of the present invention also provides a sample pretreatment method package for the method of separating multiple synthetic antioxidants from edible oils, the method package comprising the following four parts: an oil sample dissolving solution, an extraction solution, a solid extraction adsorbent, and a QuEChERS purification tube containing a purification adsorbent.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The method for separating multiple synthetic antioxidants from edible oils provided by this invention is simple to operate, similar to QuEChERS, and a single pretreatment process requires at most two QuEChERS operations, without the need for cumbersome operations such as multiple liquid-liquid extractions.

[0032] 2. The method for separating multiple synthetic antioxidants from edible oils provided by this invention has low cost of instruments and consumables. It does not require expensive instruments and consumables such as gel permeation chromatography (GPC) and gel chromatography columns, but only general laboratory equipment such as multi-tube vortex shakers and high-speed centrifuges.

[0033] 3. The method for separating multiple synthetic antioxidants from edible oils provided by this invention is highly efficient. A single pretreatment operation only takes 25 to 30 minutes, and multiple samples can be pretreated simultaneously in each pretreatment operation.

[0034] 4. The method for separating multiple synthetic antioxidants from edible oils provided by this invention is safe and environmentally friendly. It does not necessarily require the concentration and evaporation of a large amount of organic solvent, and the minimum amount of organic solvent consumed in the pretreatment of each sample is less than 15 mL.

[0035] 5. The method for separating multiple synthetic antioxidants from edible oils provided by this invention has a high recovery rate, with the recovery rate of various synthetic antioxidants generally between 80% and 100%; good stability, with the repeatability RSD of the recovery rate of each synthetic antioxidant being <5%; and good purification effect, capable of removing more than 99.5% of oil components, effectively preventing contamination and clogging of C18 liquid chromatography columns. Attached Figure Description

[0036] Figure 1 is a schematic diagram illustrating the principle of the method for separating various synthetic antioxidants from edible oils according to the present invention. Detailed Implementation

[0037] The present invention describes in detail the method for separating various synthetic antioxidants from edible oils.

[0038] A first aspect of the present invention provides a method for separating various synthetic antioxidants from edible oils, comprising the following steps:

[0039] Step 1: Dissolve and dilute the grease sample with grease sample dissolving solution to form a grease sample solution;

[0040] Step 2: Mix the sample solution obtained in Step 1 with the solid extraction adsorbent, then add the extraction solution for mixing and extraction to obtain the reaction mixture;

[0041] Step 3: Centrifuge. The reaction mixture will separate into three layers. Take the top layer solution and add a QuEChERS purification tube containing a purification adsorbent for purification treatment to obtain a solution containing a variety of synthetic antioxidants.

[0042] The edible oils described in this invention include various edible animal and vegetable oils, as well as edible oils extracted from various oily foods.

[0043] The synthetic antioxidants described in this invention refer to phenolic compounds and their derivatives that can be artificially synthesized or semi-synthesized, are soluble in edible oils, and can be used as food antioxidants. These include, but are not limited to, tert-butylhydroquinone (TBHQ), propyl gallate (PG), octyl gallate (OG), dodecyl gallate (DG), 2,6-di-tert-butyl-4-hydroxymethylphenol (Ionox-100), 4-hexylresorcinol (4-HR), amyl gallate (IAG), 2,4,5-trihydroxyphenylbutanone (THBP), nordihydroguaiacol (NDGA), tert-butylhydroanisole (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT), and ethoxyquinoline (EQ).

[0044] QuEChERS is a rapid sample pretreatment technique for agricultural product testing. The QuEChERS purification tube includes an adsorbent, magnesium sulfate, and corresponding 2mL and 15mL centrifuge tubes; a matching ceramic homogenizer can also be used. This invention does not have special requirements for the QuEChERS purification tube; commercially available QuEChERS purification tubes are sufficient.

[0045] In the method for separating various synthetic antioxidants from edible oils described above, the oil sample solution comprises solvent A and solvent B. Solvent A and solvent B are miscible at room temperature (e.g., at standard atmospheric pressure and room temperature, more specifically 20–30°C, and can dissolve in each other in any proportion), and have a boiling point above 30°C at normal pressure.

[0046] For oil samples that are liquid at room temperature, solvent A is typically liquid under experimental conditions (e.g., standard atmospheric pressure and room temperature, more specifically 20–30°C). Specifically, solvent A is usually an organic solvent with a strong dissolving ability for oils and fats at room temperature. The solubility of the oil and fat sample in solvent A is ≥2.0 g / 100 g solvent A, which can be 2.0–3.0 g / 100 g solvent A, 3.0–4.0 g / 100 g solvent A, 4.0–6.0 g / 100 g solvent A, 6.0–8.0 g / 100 g solvent A, 8.0–10.0 g / 100 g solvent A, 10.0–12.0 g / 100 g solvent A, 12.0–15.0 g / 100 g solvent A, 15.0–20.0 g / 100 g solvent A, 20.0–25.0 g / 100 g solvent A, 25.0–30.0 g / 100 g solvent A, or higher. For example, solvent A can be selected from one or more combinations of chlorinated hydrocarbon solvents, ester solvents, or ether solvents. Solvent A can be selected from dichloromethane, trichloromethane, carbon tetrachloride, various dichloroethanes, various trichloroethanes, various tetrachloroethanes, pentachloroethane, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, various propyl acetates, various butyl acetates, various amyl acetates, methyl propionate, ethyl propionate, various butyl propionate, various amyl propionate, methyl butyrate, ethyl butyrate, various propyl butyrate, various butyl butyrate, various amyl butyrate, diethyl ether, propyl ether, isopropyl ether, methyl butyl ether, tetrahydrofuran, etc. Solvent B is usually liquid under experimental conditions (e.g., standard atmospheric pressure and room temperature, more specifically 20–30°C). Specifically, solvent B is typically an organic solvent that is immiscible with the oil sample at room temperature, miscible with solvent A, and has a strong dissolving ability for various synthetic antioxidants. The solubility of various synthetic antioxidants in solvent B is ≥0.1g / 100g solvent B, 0.1~0.2g / 100g solvent B, 0.2~0.3g / 100g solvent B, 0.3~0.4g / 100g solvent B, 0.4~0.6g / 100g solvent B, 0.6~0.8g / 100g solvent B, 0.8~1.0g / 100g solvent B, 1.0~1.2g / 100g solvent B, 1.2~1.5g / 100g solvent B, 1.5~2.0g / 100g solvent B, 2.0~2.5g / 100g solvent B, 2.5~3.0g / 100g solvent B, or higher. For example, solvent B may be selected from one or more of methanol, ethanol, acetonitrile, propionitrile, etc.

[0047] For grease samples that are solid at room temperature, solvent A is typically liquid under experimental conditions (e.g., standard atmospheric pressure and room temperature, more specifically 20–30°C). Specifically, solvent A is typically an organic solvent with strong dissolving power for greases at room temperature. The solubility of the grease sample in solvent A is ≥2 g / 100 g solvent A, and can be 2–3 g / 100 g solvent A, 3–4 g / 100 g solvent A, 4–6 g / 100 g solvent A, 6–8 g / 100 g solvent A, 8–10 g / 100 g solvent A, 10–12 g / 100 g solvent A, 12–15 g / 100 g solvent A, 15–20 g / 100 g solvent A, 20–25 g / 100 g solvent A, 25–30 g / 100 g solvent A, or higher. Solvent A can be selected from one or more of the same chlorinated hydrocarbon solvents, ester solvents, or ether solvents as the liquid oil sample described above, or from aromatic hydrocarbon solvents, such as benzene, toluene, xylene, trimethylbenzene, etc. Solvent B is typically liquid under experimental conditions (e.g., standard atmospheric pressure and room temperature, more specifically 20–30°C). Specifically, solvent B is typically an organic solvent, miscible with solvent A, and either miscible or immiscible with the oil sample at room temperature. It also has a strong dissolving ability for various synthetic antioxidants, with the solubility of various synthetic antioxidants in solvent B being ≥0.1 g / 100 g solvent B, 0.1–0.2 g / 100 g solvent B, 0.2–0.3 g / 100 g solvent B, 0.3–0.4 g / 100 g solvent B, 0… The solvent B has a solubility of 0.4–0.6 g / 100g, 0.6–0.8 g / 100g, 0.8–1.0 g / 100g, 1.0–1.2 g / 100g, 1.2–1.5 g / 100g, 1.5–2.0 g / 100g, 2.0–2.5 g / 100g, 2.5–3.0 g / 100g, or higher. For example, solvent B may be selected from any one or more aromatic hydrocarbon solvents and acetonitrile. The aromatic hydrocarbon solvents include, but are not limited to, any one or more of benzene, toluene, xylene, and trimethylbenzene. Solvent B does not contain any components identical to those in solvent A. For example, if solvent A contains benzene and xylene, solvent B does not contain benzene and xylene, but may contain one or more of toluene and trimethylbenzene.

[0048] The solubility of the synthetic antioxidant in the extract of this invention is ≥0.10 g / 100 g extract, and the solubility of the oil sample is ≤1.0 g / 100 g extract. The solubility of the synthetic antioxidant in the extract can be 0.1–0.2 g / 100 g extract, 0.2–0.3 g / 100 g extract, 0.3–0.4 g / 100 g extract, 0.4–0.6 g / 100 g extract, 0.6–0.8 g / 100 g extract, 0.8–1.0 g / 100 g extract, 1.0–1.2 g / 100 g extract, 1.2–1.5 g / 100 g extract, 1.5–2.0 g / 100 g extract, or 2.0–2.5 g. The solubility of the oil sample in the extract can be 1.0–0.8 g / 100g extract, 0.8–0.6 g / 100g extract, 0.6–0.4 g / 100g extract, 0.4–0.2 g / 100g extract, 0.2–0.1 g / 100g extract, 0.1–0.05 g / 100g extract, 0.05–0.01 g / 100g extract, or lower. In some embodiments of the present invention, the extract includes one or more of methanol, ethanol, acetonitrile, N,N-dimethylformamide, N,N-diethylformamide, and N,N-dimethylacetamide. In some preferred embodiments of the present invention, the extract comprises 10% by volume methanol, N,N-dimethylformamide, N,N-diethylformamide or N,N-dimethylacetamide and 90% by volume ethanol or acetonitrile.

[0049] The specific principle of the method for separating multiple synthetic antioxidants from edible oils provided by this invention is shown in Figure 1. First, the oil sample is dissolved and diluted with an oil sample dissolving solution to form an oil sample solution (refer to Figure 1a). Then, it is mixed with a solid extraction adsorbent, so that the oil sample solution is dispersed and coated on the surface of the solid phase particles of the solid extraction adsorbent (refer to Figure 1b). Then, a certain amount of extraction solution is added (refer to Figure 1c) for mixed extraction. During this extraction process, the oil sample solution coated on the surface of the solid phase particles of the solid extraction adsorbent will permeate and flow into the extraction solution because the oil sample dissolving solution contained therein is easily soluble in the extraction solution. Simultaneously, it will "carry in" various synthetic antioxidants in the oil sample solution and dissolve them in the extraction solution. At the same time, the oil sample in the oil sample solution, due to its base... The extract, insoluble in the extractant, separates from the oil sample solution (including the synthetic antioxidants "carried out" by it) and is concentrated and adsorbed onto the surface of the solid particles of the solid extraction adsorbent, forming a solid-phase supported, high-surface-area double-liquid-layer permeation extraction microstructure. This achieves the separation of multiple synthetic antioxidants from the oil (refer to Figure 1d). Next, centrifugation disrupts this solid-phase supported, high-surface-area double-liquid-layer permeation extraction microstructure. After centrifugation, the entire reaction mixture separates into three layers (refer to Figure 1e): the bottom layer is the solid extraction adsorbent, the middle layer is the oil sample, and the top layer is an organic solution layer formed by the miscibility of the extractant and the oil sample solution permeating from the original oil sample solution. This layer is enriched with the synthetic antioxidants extracted from the oil sample and trace amounts of co-extracted oil impurities. Finally, a certain volume of the upper organic solution is taken and added to a QuEChERS purification tube containing a purification adsorbent. The QuEChERS purification process removes the trace amounts of co-extracted oil impurities from the upper organic solution, yielding a solution containing multiple synthetic antioxidants. By measuring the content of various synthetic antioxidants in the obtained solution containing multiple synthetic antioxidants, the concentration of each antioxidant in the original oil sample can be calculated.

[0050] In this invention, for safety reasons, the components of the oil sample dissolving solution and the extract are preferably organic solvents of low to medium toxicity and non-toxic varieties.

[0051] Alternatively, if the resulting solution containing multiple synthetic antioxidants is to be concentrated, the components of the oil sample solution and the extract should preferably be organic solvents with a boiling point below 100°C at normal pressure.

[0052] In some embodiments of the present invention, the volume ratio of the oil sample dissolving solution to the oil sample is 2–20:1, which can be 2–5:1, 5–10:1, 10–15:1, or 15–20:1. The amount of oil sample weighed is usually 0.1–0.3 g, approximately 0.1–0.3 mL. At room temperature, as long as at least twice the volume of the oil sample dissolving solution is added to the oil sample, the oil sample can be completely dissolved and form an oil sample solution. Furthermore, for edible oils that are solid at room temperature, the formed oil sample solution will not cause the dissolved solid oil sample to solidify and precipitate again within at least 25 minutes at room temperature.

[0053] In the above method for separating various synthetic antioxidants from edible oils, a suitable ratio between solvent A and solvent B is required in the oil sample solution to improve the subsequent separation and extraction effects. For edible oils that are liquid at room temperature, the volume of solvent B in the total volume of the oil sample solution is 20%–50%, specifically 20%–25%, 25%–30%, 30%–35%, 35%–40%, 40%–45%, or 45%–50%, preferably 30%–40%. For edible oils that are solid at room temperature, the volume of solvent B in the total volume of the oil sample solution is 30%–70%, specifically 30%–40%, 40%–50%, 50%–60%, or 60%–70%, preferably 40%–60%.

[0054] In some embodiments of the present invention, the volume ratio of the extract to the oil sample is 2 to 10:1, and can be 2 to 4:1, 4 to 6:1, 6 to 8:1, or 8 to 10:1.

[0055] In some embodiments of the present invention, the extract contains acetic acid or formic acid; preferably, the volume fraction of the acetic acid or formic acid is 0.05% to 2%, which can be 0.05% to 0.1%, 0.1% to 0.5%, 0.5% to 1%, 1% to 1.5%, or 1.5% to 2%, and most preferably 0.1% to 1%.

[0056] In some embodiments of the present invention, the extract contains lipoic acid or sesamol; preferably, the proportion of lipoic acid is 0.01wt% to 0.10wt%, which can be 0.01wt% to 0.02wt%, 0.02wt% to 0.04wt%, 0.04wt% to 0.06wt%, 0.06wt% to 0.08wt%, or 0.08wt% to 0.10wt%; or the proportion of sesamol is 0.1wt% to 0.5wt%, which can be 0.1wt% to 0.2wt%, 0.2wt% to 0.3wt%, 0.3wt% to 0.4wt%, or 0.4wt% to 0.5wt%.

[0057] In some embodiments of the present invention, the solid adsorbent is silica particles, wherein the silica content is greater than 99.5%. Specifically, the silica particles have a cleanliness that meets the requirements of analytical chemistry, including but not limited to fine sand, rock sand, sea sand, gravel, sand, granules, quartz sand, glass sand, etc. Preferably, the silica particles are natural, rough-surfaced fine sand, such as rock sand, sea sand, gravel, sand, granules, etc. In some embodiments of the present invention, the mesh size of the silica particles is 20-160, and can be 20-40, 40-60, 60-80, 80-100, 100-120, 120-140, 140-160, preferably 30-120.

[0058] In some embodiments of the present invention, the specific gravity of the solid adsorbent is 2.2 to 3 times that of the oil sample.

[0059] In some embodiments of the present invention, in order to ensure that the oil sample solution is fully dispersed and coated on the solid phase particle surface of the solid extraction adsorbent in step two, two conditions need to be met: 1) the volume of the oil sample solution added to each 10g of the solid extraction adsorbent is 1.0 to 4.0 mL, preferably 2.0 to 3.0 mL; 2) after the oil sample solution is added to the solid extraction adsorbent, it is allowed to stand at room temperature for a time of 3 min or more, which can be 3 min, 4 min, 5 min, 6 min, etc., preferably 5 min or more.

[0060] In some embodiments of the present invention, the mixing and extraction in step two adopts a vortex oscillation method, specifically, vortex oscillation at 2000-3500 rpm for 30-120 s, preferably 45-90 s, more preferably 60-75 s.

[0061] In some embodiments of the present invention, the centrifugation in step three is high-speed centrifugation with a rotation speed of 4000-10000 rpm, which can be 4000-5000 rpm, 5000-6000 rpm, 6000-7000 rpm, 7000-8000 rpm, 8000-9000 rpm, or 9000-10000 rpm.

[0062] For liquid edible oils, high-speed centrifugation disrupts the microstructure of the solid-phase-supported, high-surface-area bilayer permeation extraction. After centrifugation, the entire extraction reaction mixture separates into three layers: the top layer is an organic solution layer formed by the mutual dissolution of the extract and the oil sample solution that permeated from the original oil sample solution; the middle layer is the oil sample layer; and the bottom layer is a solid adsorbent layer. For solid edible oils, centrifugation also separates the entire extraction reaction mixture into three layers: the top layer is an organic solution layer formed by the mutual dissolution of the extract and the oil sample solution that permeated from the original oil sample solution; and the bottom layer is a solid extraction adsorbent layer covered by re-solidified solid oil. To ensure the above effects are achieved, the specific gravity of the mixed organic solution formed by the mutual dissolution of the extract and the oil sample solution used in a single extraction reaction needs to be lower than the specific gravity of the corresponding edible animal or vegetable oil.

[0063] In some preferred embodiments of the present invention, the oil sample solution and the extract satisfy the following relationship: the volume percentage of solvent A in the oil sample solution used for a single extraction is 30% to 5% of the total volume of the oil sample solution and the extract used, preferably 20% to 5%, and more preferably 15% to 5%.

[0064] In some embodiments of the present invention, the purification adsorbent in step three is a C18 (terminated) adsorbent. The C18 (terminated) adsorbent is based on bonded reverse-phase extraction (octadecyltrichlorosilane), using high-purity irregular silica gel as a matrix, and undergoes end-group capping treatment. It exhibits a typical reverse-phase extraction retention mechanism, demonstrating excellent strong retention characteristics for non-polar compounds and retaining most organic substances. It is a widely used SPE adsorbent. Its particle size is 40-60 μm, and its specific surface area is 400-800 m². 2 / g, the dosage is 0.05~0.30g.

[0065] In some embodiments of the present invention, the purification process in step three is carried out by vortex oscillation, specifically by vortex oscillation at 2000-3000 rpm for 1-5 minutes to fully mix and react.

[0066] A second aspect of this invention provides the application of the above-described method for separating multiple synthetic antioxidants from edible oils in the detection of antioxidant content in edible oils. This invention employs a high surface area double-layer permeation extraction technique with solid-phase support to separate, extract, and purify multiple synthetic antioxidants from edible oils. The resulting solution containing multiple synthetic antioxidants can be concentrated or not for use in various chemical analysis techniques (such as high-performance liquid chromatography, gas chromatography, high-performance liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, etc.) to detect the content of these synthetic antioxidants. Alternatively, it can be diluted with water for use in immunological analysis techniques (such as ELSA, colloidal gold immunochromatography, etc.) to detect these synthetic antioxidants.

[0067] A third aspect of the present invention also provides a sample pretreatment method package adapted to the method of the present invention for separating multiple synthetic antioxidants from edible oils, the method package comprising the following four parts: an oil sample dissolving solution, an extraction solution, a solid extraction adsorbent, and a QuEChERS purification tube containing a purification adsorbent.

[0068] The following detailed description of specific embodiments of the present invention, in conjunction with preferred embodiments, further illustrates the relevant details. When numerical ranges are given in the embodiments, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range, as well as any value between the two endpoints, may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by those skilled in the art. In addition to the specific methods, devices, and materials used in the embodiments, the present invention can be implemented using any prior art methods, devices, and materials similar to or equivalent to those described in the embodiments of the present invention, provided that those skilled in the art possess the prior art and the description of the present invention.

[0069] Example 1

[0070] Oil sample: Grade I extracted soybean oil (with known concentrations of TBHQ tert-butylhydroquinone, NDGA nordihydroguaiacol and BHT 2,6-di-tert-butyl-4-methylphenol added);

[0071] Oil sample dissolving solution: Solvent A (chloroform): Solvent B (methanol) = 3:1;

[0072] Extraction solution: Acetonitrile: Methanol = 9:1 (containing 0.5% acetic acid and 0.01% lipoic acid);

[0073] Weigh 0.8 g (approximately 0.8 mL) of the oil sample and dissolve it completely in 2.2 mL of oil sample dissolving solution to form an oil sample solution. Add the entire oil sample solution to a reaction vessel containing 10 g of sea sand (50-100 mesh). Let it stand at room temperature for 4 min, then add 6 mL of extraction solution. Immediately afterward, vortex the mixture at 3000 rpm for 75 s, then immediately centrifuge at 6000 rpm for 5 min to separate the layers. Then, take 6 mL of the uppermost organic solution into a container pre-filled with 0.15 g of... In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 2000 rpm for 3 min on a vortex mixer. Then, it was centrifuged again at 6000 rpm for 5 min. 4 mL of the supernatant was transferred to a 10 mL graduated glass tube and incubated in a 40°C water bath with nitrogen to a final volume of approximately 0.5 mL. The volume was then adjusted to 2 mL with methanol. The solution was filtered through a 0.22 μm nylon filter and subjected to gas chromatography analysis. Specific gas chromatography detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016, "National Food Safety Standard - Determination of Nine Antioxidants in Food".

[0074] Example 2

[0075] Oil sample: solid margarine (with known concentrations of PG, BHA, EQ and DG added);

[0076] Oil sample dissolving solution: Solvent A (ethyl acetate): Solvent B (benzene) = 1:1;

[0077] Extract: Ethanol: Methanol = 9:1 (containing 1.5% formic acid and 0.1% sesamol);

[0078] Weigh 0.25 g (approximately 0.25 mL) of the grease sample that has been melted into a liquid state at high temperature. Dissolve it completely in 0.90 mL of grease sample dissolving solution to form a grease sample solution. Add the entire grease sample solution to a reaction vessel containing 10 g of fine sand (80-120 mesh). Let it stand at room temperature for 3 minutes, then add 10 mL of extraction solution. Immediately afterward, vortex the mixture at 2000 rpm for 90 seconds. Then, immediately centrifuge at 4000 rpm for 5 minutes to separate the layers. Finally, take 8 mL of the uppermost organic solution into a container pre-filled with 0.25 g of grease sample solution. In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 2500 rpm for 5 min on a vortex mixer. Then, it was centrifuged again at 6000 rpm for 5 min. 6 mL of the supernatant was transferred to a 50 mL flat-bottomed glass flask, and the solvent was evaporated to dryness by rotary evaporation in a 40°C water bath. Finally, 2 mL of methanol was added to dissolve the residue in the flask. The solution was filtered through a 0.22 μm nylon filter membrane and then subjected to gas chromatography. Specific gas chromatography detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016 "National Food Safety Standard - Determination of Nine Antioxidants in Food".

[0079] Example 3

[0080] Oil samples: Liquid oils extracted from fried noodles (with known concentrations of THBP, IAG, 4-HR, DG and OG added);

[0081] Oil sample dissolving solution: Solvent A (isopropyl ether: 1,2-dichloroethane = 4:1): Solvent B (methanol: propionitrile = 3:1) = 2.5:1;

[0082] Extraction solution: Acetonitrile: N,N-dimethylformamide = 9:1 (containing 2.5% formic acid and 0.3% sesamol);

[0083] Weigh 2.0 g (approximately 2.0 mL) of the oil sample and dissolve it completely in 6 mL of oil sample dissolving solution to form an oil sample solution. Add the entire oil sample solution to a reaction vessel containing 20 g of rock sand (30-80 mesh). After standing at room temperature for 5 min, add 14 mL of extract and immediately vortex at 2500 rpm for 105 s. Then, immediately centrifuge at 8000 rpm for 5 min to separate the layers. Take 5 mL of the uppermost organic solution into a QuEChERS purification tube pre-loaded with 0.20 g of C18 (end-capped) adsorbent. Vortex at 2500 rpm for 4 min and centrifuge again at 6000 rpm for 5 min. Take 3 mL of the supernatant and filter it through a 0.22 μm nylon filter membrane for liquid chromatography determination. Refer to GB for specific liquid chromatography detection conditions. The relevant technical requirements of National Food Safety Standard 5009.32-2016, "Determination of Nine Antioxidants in Food", shall be followed.

[0084] Example 4

[0085] Oil sample: Solid hydrogenated oil extracted from vegetable fat cream (with known concentrations of TBHQ, Ionox-100, BHA and BHT added);

[0086] Oil sample dissolving solution: Solvent A (methyl tert-butyl ether: isobutyl acetate = 5:2): Solvent B (toluene: o-xylene = 2:1) = 2:1;

[0087] Extraction solution: ethanol: N,N-dimethylacetamide = 9:1 (containing 1.0% acetic acid and 0.05% lipoic acid);

[0088] Weigh 1.0 g (approximately 1.0 mL) of the grease sample that has been melted into a liquid state at high temperature. Dissolve it completely in 10 mL of grease sample dissolving solution to form a grease sample solution. Add the entire grease sample solution to a reaction vessel containing 25 g of sand (100-150 mesh). Let it stand at room temperature for 7.5 min. Then add 25 mL of extraction solution and immediately vortex at 2800 rpm for 120 s to mix thoroughly. Immediately afterward, centrifuge at 10000 rpm for 5 min to separate the layers. Then, take 10 mL of the uppermost organic solution into a container pre-filled with 0.25 g of sand. In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 3000 rpm for 2 min on a vortex mixer. Then, it was centrifuged again at 6000 rpm for 5 min. 5 mL of the supernatant was then filtered through a 0.22 μm nylon filter membrane and subjected to liquid chromatography. The specific liquid chromatography detection conditions were in accordance with the relevant technical requirements of GB 5009.32-2016 "National Food Safety Standard - Determination of Nine Antioxidants in Food".

[0089] Example 5

[0090] Oil sample: First-grade pressed corn oil (with known concentration of TBHQ added);

[0091] Oil sample dissolving solution: Solvent A (diethyl ether: butyl formate = 1:1): Solvent B (acetonitrile) = 4:1;

[0092] Extraction solution: Ethanol: Methanol = 9:1 (containing 0.05% acetic acid and 0.025% lipoic acid);

[0093] Weigh 0.5 g (approximately 0.5 mL) of the oil sample and dissolve it completely in 2.5 mL of oil sample dissolving solution. Add the entire oil sample solution to a reaction vessel containing 10 g of sand (90-120 mesh). Let it stand at room temperature for 6 minutes, then add 5.5 mL of extraction solution. Immediately afterward, vortex the mixture at 2600 rpm for 50 seconds. Then, immediately centrifuge at 7000 rpm for 5 minutes to separate the layers. Finally, take 3.5 mL of the uppermost organic solution into a container pre-filled with 0.20 g of... In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 2400 rpm for 5 min on a vortex mixer. After centrifugation at 6000 rpm for 5 min, 2.0 mL of the supernatant was collected, filtered through a 0.22 μm nylon filter membrane, and the TBHQ content was rapidly determined using the reagents provided in the TBHQ colloidal gold rapid detection kit according to the kit's instructions.

[0094] Example 6

[0095] Oil sample: solid shortening (with known concentration of BHA added);

[0096] Oil sample dissolving solution: Solvent A (propyl ether): Solvent B (acetonitrile: ethanol) = 2:3;

[0097] Extraction solution: Acetonitrile: N,N-dimethylformamide = 9:1 (containing 0.25% formic acid and 0.45% sesamol);

[0098] Weigh 0.4 g (approximately 0.4 mL) of the grease sample that has been melted into a liquid state at high temperature. Dissolve it completely in 2.0 mL of grease sample dissolving solution to form a grease sample solution. Add the entire grease sample solution to a reaction vessel containing 10 g of glass frit (60-100 mesh). Let it stand at room temperature for 4 min, then add 5.0 mL of extraction solution. Immediately afterward, vortex the mixture at 2200 rpm for 60 s, then immediately centrifuge at 7600 rpm for 5 min to separate the layers. Then, take 5 mL of the uppermost organic solution into a container pre-filled with 0.30 g of... In a QuEChERS purification tube containing C18 (terminated) adsorbent, the mixture was thoroughly vortexed at 2600 rpm for 4 min, followed by centrifugation at 6000 rpm for 5 min. 1.0 mL of the supernatant was then filtered through a 0.22 μm nylon filter and subjected to rapid BHA content detection using the reagents provided in the BHA enzyme-linked immunofluorescence adsorption (ELISA) rapid detection kit.

[0099] Example 7

[0100] Oil sample: liquid edible oil extracted from cookies (with known concentrations of IAG and DG added);

[0101] Oil sample dissolving solution: Solvent A: methyl propionate; Solvent B: methanol. Then, solvent B and solvent A were mixed in different proportions to prepare eight oil sample dissolving solutions with solvent B contents of 5%, 10%, 20%, 30%, 40%, 50%, 60%, and 70%, respectively. Eight sets of pretreatment experiments were then carried out.

[0102] Extraction solution: Acetonitrile: Methanol = 9:1 (containing 1.0% acetic acid and 0.05% lipoic acid);

[0103] Weigh 1.0 g (approximately 1.0 mL) of the oil sample and dissolve it completely in 2.0 mL of oil sample dissolving solution to form an oil sample solution. Add the entire oil sample solution to a reaction vessel containing 10 g of sea sand (60-120 mesh). Let it stand at room temperature for 5 min, then add 8 mL of extraction solution. Immediately afterward, vortex the mixture at 2700 rpm for 70 s, then immediately centrifuge at 7500 rpm for 5 min to separate the layers. Then, take 6 mL of the uppermost organic solution into a container pre-filled with 0.25 g of... In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 2400 rpm for 5 min on a vortex mixer. Then, it was centrifuged again at 6000 rpm for 5 min. 5 mL of the supernatant was transferred to a 10 mL graduated glass tube and incubated in a 40℃ water bath with nitrogen to a final volume of approximately 0.5 mL. The volume was then adjusted to 2 mL with acetonitrile. The solution was filtered through a 0.22 μm nylon filter and subjected to gas chromatography analysis. Specific gas chromatography detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016, "National Food Safety Standard - Determination of Nine Antioxidants in Food". The recoveries of IAG and DG in each of the eight experimental groups were calculated. The solubility of 2 mL of the oil sample solution and 1 g (approximately 1.0 mL) of the oil sample after thorough mixing was also observed in each group. The results are shown in Table 1.

[0104] Table 1

[0105]

[0106] As shown in Table 1, for edible oils that are liquid at room temperature, the recovery rates of IAG and DG increase accordingly with the increasing proportion of solvent B in the oil sample solution. When the proportion of solvent B in the oil sample solution reaches 20%, the recovery rates of IAG and DG reach over 70%, meeting the minimum recovery rate requirements of general chemical analysis techniques. Furthermore, when the proportion of solvent B reaches 30% or more, the recovery rates of IAG and DG reach over 80%, meeting the excellent recovery rate requirements of general chemical analysis techniques. However, at the same time, with the increase of the proportion of solvent B in the oil sample solution, the solubility of the oil sample solution for edible oils decreases significantly, leading to a decrease in the recovery rates of IAG and DG. According to the technical requirements stated in claim 4, at room temperature, the oil sample can be completely dissolved by adding a maximum of twice the volume of the oil sample solution. When the proportion of solvent B in the oil sample solution reaches 50%, the solution can barely dissolve the oil sample, but the recovery rates of IAG and DG have decreased to some extent. When the proportion of solvent B in the oil sample solution reaches 60%, the solution cannot dissolve the oil sample into a solution, resulting in a significant decrease in the recovery rates of IAG and DG. Therefore, in the technology described in this invention, for edible oils that are liquid at room temperature, the proportion of solvent B in the oil sample solution is 20% to 50%, preferably 30% to 40%.

[0107] Example 8

[0108] Oil sample: solid edible tallow (with known concentrations of BHA and BHT added);

[0109] Oil sample dissolving solution: Solvent A (isopropyl acetate: 1,1,2-trichloroethane = 7:1); Solvent B (toluene: m-xylene = 4:1). Then, solvent B and solvent A were mixed in different proportions to prepare nine oil sample dissolving solutions with solvent B contents of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%, respectively. Nine sets of pretreatment experiments were then conducted.

[0110] Extraction solution: ethanol: N,N-dimethylformamide = 9:1 (containing 2.0% formic acid and 0.25% sesamol);

[0111] Weigh 1.25 g (approximately 1.25 mL) of the liquefied oil sample, which has been melted at high temperature. Dissolve it completely in 2.5 mL of oil sample dissolving solution to form an oil sample solution. Add the entire oil sample solution to a reaction vessel containing 15 g of rock sand (50-100 mesh). Let it stand at room temperature for 5 min, then add 10 mL of extraction solution. Immediately afterward, vortex the mixture at 2800 rpm for 80 s, then immediately centrifuge at 6800 rpm for 5 min to separate the layers. Then, take 8 mL of the uppermost organic solution into a container pre-filled with 0.25 g of... In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 2700 rpm for 2 min on a vortex mixer, followed by centrifugation at 6000 rpm for 5 min. 2 mL of the supernatant was collected, filtered through a 0.22 μm nylon filter, and then subjected to high-performance liquid chromatography (HPLC). Specific HPLC detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016, "National Food Safety Standard - Determination of Nine Antioxidants in Food". The recoveries of BHA and BHT in each of the nine experimental groups were calculated. Simultaneously, the fastest recrystallization time of the oil sample in the oil sample solution after dissolving in the oil sample solution and standing at room temperature was observed in each experimental group. The results are shown in Table 2.

[0112] Table 2

[0113]

[0114]

[0115] As shown in Table 2, for edible oils that are solid at room temperature, when the proportion of solvent B in the oil sample solution is less than 30%, and the volume of the oil sample solution used to dissolve the oil sample is twice the volume of the oil sample being dissolved (meeting the minimum dilution factor in claim 4), the fastest time for solid oil to crystallize out again in the obtained oil sample solution is less than 25 minutes. Such a short time cannot meet the requirements for completing the entire separation and extraction experimental process. When the proportion of solvent B reaches 30% to 70%, the recovery rates of BHA and BHT reach over 70%, meeting the minimum recovery rate requirements of general chemical analysis techniques. Furthermore, if the proportion of solvent B reaches 40% to 60%, the recovery rates of BHA and BHT reach over 80%, meeting the excellent recovery rate requirements of general chemical analysis techniques. Therefore, in the technology described in this invention, for edible oils that are solid at room temperature, the volume proportion of solvent B in the oil sample solution is 30% to 70%, preferably 40% to 60%.

[0116] Example 9

[0117] Oil sample: liquid edible oil extracted from sunflower seed kernels (with known concentrations of TBHQ and Ionox-100 added); oil sample solution: solvent A (ethyl acetate: isopropyl ether = 9:1): solvent B (ethanol) = 3:2;

[0118] Extraction solution: First, prepare a mixed solvent of acetonitrile:methanol = 9:1 (containing 0.08% lipoic acid). Then, use this mixed solvent to prepare extraction solutions with acetic acid concentrations of 0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, and 2.0. Each acetic acid concentration extraction solution was used to conduct a separation and extraction experiment of synthetic antioxidants from one group of oil samples. A total of 12 groups of experiments were conducted.

[0119] Weigh 0.75 g (approximately 0.75 mL) of the oil sample and dissolve it completely in 2.0 mL of oil sample dissolving solution. Add the oil sample solution to a reaction vessel containing 10 g of sand (30-80 mesh). Let it stand at room temperature for 10 min, then add 7.25 mL of extract. Immediately afterward, vortex at 2500 rpm for 90 s to mix thoroughly. Then, centrifuge at 5000 rpm for 5 min to separate the layers. Take 4 mL of the uppermost organic solution into a QuEChERS purification tube pre-loaded with 0.20 g of C18 (end-capped) adsorbent. Vortex at 2000 rpm for 3 min to mix thoroughly. Then, centrifuge again at 6000 rpm for 5 min. Take 2 mL of the supernatant, filter it through a 0.22 μm nylon filter membrane, and perform liquid chromatography analysis. Refer to GB for specific liquid chromatography detection conditions. The relevant technical requirements of National Food Safety Standard 5009.32-2016, "Determination of Nine Antioxidants in Food," were followed. The recovery rates of TBHQ and Ionox-100 in each of the 12 experimental groups were calculated, and the results are shown in Table 3.

[0120] Table 3

[0121]

[0122]

[0123] As shown in Table 3, compared with the extract without acetic acid, the recovery rate of the synthesized antioxidant was significantly improved even with the addition of 0.05% acetic acid to the extract. The recovery rate continued to increase with the increase of acetic acid content in the extract. When the acetic acid concentration in the extract reached 1.0% or higher, the recovery rate of the synthesized antioxidant stabilized at its maximum value. Therefore, adding 0.05% to 2.0% acetic acid to the extract, preferably 0.1% to 1.0%, can significantly improve the recovery rate of the synthesized antioxidant.

[0124] Example 10

[0125] Oil sample: Palm sterols (solid edible oil) (with known concentrations of 4-HR and THBP added);

[0126] Oil sample dissolving solution: Solvent A (chloroform): Solvent B (acetonitrile: methanol = 1:1) = 3:1;

[0127] Extraction solutions: Extraction solutions containing 0.2% sesamol were prepared in acetonitrile with formic acid concentrations of 0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, and 2.0. Each formic acid concentration was used to conduct the separation and extraction experiment of synthetic antioxidants from one group of oil samples. A total of 12 groups of experiments were conducted.

[0128] Weigh 1.25 g (approximately 1.25 mL) of the oil sample and dissolve it completely in 3.0 mL of oil sample dissolving solution. Add the entire oil sample solution to a reaction vessel containing 15 g of sand (40-100 mesh). Let it stand at room temperature for 8 minutes, then add 9 mL of extraction solution. Immediately afterward, vortex the mixture at 2400 rpm for 60 seconds. Then, immediately centrifuge at 5500 rpm for 5 minutes to separate the layers. Finally, take 10 mL of the uppermost organic solution and add it to a container pre-filled with 0.22 g of... In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 2100 rpm for 2.5 min on a vortex mixer. Then, it was centrifuged again at 6000 rpm for 5 min. 8 mL of the supernatant was collected and purged with nitrogen to approximately 0.5 mL in a 40℃ water bath. Finally, the volume was adjusted to 2 mL with acetonitrile. The solution was filtered through a 0.22 μm nylon membrane and subjected to gas chromatography analysis. Specific gas chromatography detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016 "National Food Safety Standard - Determination of Nine Antioxidants in Food". The recovery rate of THBP in each of the 12 experimental groups over 4 hours was calculated, and the results are shown in Table 4.

[0129] Table 4

[0130]

[0131]

[0132] As shown in Table 4, compared with the extract without formic acid, the recovery rate of the synthesized antioxidant is significantly improved even with the addition of 0.05% formic acid to the extract. The recovery rate increases with the increase of formic acid content in the extract. When the formic acid concentration in the extract reaches 1.0% or higher, the recovery rate of the synthesized antioxidant stabilizes at its maximum value. Therefore, adding 0.05% to 2.0% formic acid to the extract, preferably 0.1% to 1.0%, can significantly improve the recovery rate of the synthesized antioxidant.

[0133] Example 11

[0134] Oil sample: liquid edible oil extracted from bread (with known concentrations of TBHQ and Ionox-100 added);

[0135] Oil sample dissolving solution: Solvent A (propyl formate: diethyl ether = 5:1): Solvent B (ethanol: methanol = 2:1);

[0136] Extraction solution: composed of N,N-dimethylformamide and acetonitrile in different proportions, containing 0.06% lipoic acid and 0.2% formic acid. Each extraction solution with different proportions was used for a separation and extraction experiment, for a total of 8 experiments, as detailed in Table 5.

[0137] Weigh 0.2 g (approximately 0.2 mL) of the oil sample and dissolve it completely in 1.9 mL of oil sample dissolving solution to form an oil sample solution. Add the entire oil sample solution to a reaction vessel containing 10 g of quartz sand (70-100 mesh). After standing at room temperature for 6 min, add 8.1 mL of extract and immediately vortex at 2300 rpm for 85 s. Then, immediately centrifuge at 4000 rpm for 5 min to separate the layers. Take 8 mL of the uppermost organic solution into a QuEChERS purification tube pre-loaded with 0.10 g of C18 (end-capped) adsorbent and vortex at 2800 rpm for 3.5 min. Then, centrifuge again at 6000 rpm for 5 min. Take 2 mL of the supernatant, filter it through a 0.22 μm nylon filter membrane, and perform liquid chromatography analysis. Refer to GB for specific liquid chromatography detection conditions. The relevant technical requirements of National Food Safety Standard 5009.32-2016, "Determination of Nine Antioxidants in Food," were followed. Each of the eight experimental groups was performed six times simultaneously. The relative standard deviation (RSD) of the NDGA recovery rate for each group was calculated, and the residual oil content per milliliter of the extract obtained from each group was also measured. The results are shown in Table 5.

[0138] Table 5

[0139]

[0140]

[0141] As shown in Table 5, when the proportion of acetonitrile in the extract is greater than or equal to 90%, the repeatability of the NDGA recovery rate is good (relative standard deviation RSD less than 5%). However, when the proportion of acetonitrile in the extract is less than or equal to 90%, the residual oil content in the final extract is relatively low (less than 1 mg / mL). Using ethanol instead of acetonitrile, or methanol, N,N-diethylformamide, or N,N-dimethylacetamide instead of N,N-dimethylformamide, can also yield similar results to those in Table 5. Considering both the good repeatability of the synthesized antioxidant and the low residual oil content in the extract, the preferred extract formulation is 10% methanol or N,N-dimethylformamide or N,N-diethylformamide or N,N-dimethylacetamide and 90% ethanol or acetonitrile.

[0142] Example 12

[0143] Oil sample: Liquid pressed first-grade rice bran oil (with known concentrations of DG and EQ added);

[0144] Oil sample dissolving solution: Solvent A (ethyl butyrate): Solvent B (methanol) = 3:1;

[0145] Extraction solution: Acetonitrile: N,N-dimethylacetamide = 9:1 (containing 1.0% acetic acid and 0.3% sesamol);

[0146] Weigh 0.5 g (approximately 0.5 mL) of the oil sample and dissolve it completely in 1.5 mL of oil sample dissolving solution to form an oil sample solution. Add the entire oil sample solution to a reaction vessel containing 10 g of fine sand (40-80 mesh). Let it stand at room temperature for 7.5 min, then add 8.5 mL of extraction solution. Immediately afterward, vortex the mixture at 2200 rpm for 65 s, then centrifuge at 4500 rpm for 5 min to separate the layers. Then, take 6 mL of the uppermost organic solution into a QuEChERS purification tube pre-loaded with 0.30 g of C18 (end-capped) adsorbent. Vortex the mixture at 2700 rpm for 4.5 min, then centrifuge again at 6000 rpm for 5 min. Take 2 mL of the supernatant, filter it through a 0.22 μm nylon filter membrane, and perform liquid chromatography analysis. Refer to GB for specific liquid chromatography detection conditions. The relevant technical requirements of National Food Safety Standard 5009.32-2016, "Determination of Nine Antioxidants in Food," were followed. The residual oil content per milliliter of the obtained extract was then determined. The above experiment was repeated multiple times, each time using a different type of solid adsorbent, with the same dosage and particle size range. The results are shown in Table 6.

[0147] Table 6

[0148]

[0149] As shown in Table 6, the experimental data reveals that using natural, rough-surfaced fine sand, rock sand, sea sand, gravel, sand particles, and sand grains as solid adsorbents results in a significantly lower residual oil content in the final extract compared to extracts obtained using molten, crystallized, smooth-surfaced quartz sand and glass sand as solid adsorbents. Therefore, the use of natural, rough-surfaced fine sand, rock sand, sea sand, gravel, sand particles, and sand grains as solid adsorbents is preferred.

[0150] Example 13

[0151] Oil sample: liquid edible oil extracted from sunflower seed kernels (roasted) (with known concentrations of THBP and BHT added); oil sample solution: solvent A (pentachloroethane: propyl ether = 2:1): solvent B (ethanol: acetonitrile = 5:2);

[0152] Extraction solution: N,N-dimethylformamide (containing 2.0% formic acid and 0.5% sesamol);

[0153] Weigh 0.4 g (approximately 0.4 mL) of the oil sample and completely dissolve it in 1.2 mL of oil sample dissolving solution to prepare 21 separate oil sample solutions. Add each oil sample solution to a reaction vessel containing 10 g of silica particles (chemical reagent grade) of 21 different particle sizes. After standing at room temperature for 5 min, add 6.8 mL of extraction solution and immediately vortex at 2750 rpm for 60 s. Then, immediately centrifuge at 4800 rpm for 5 min to separate the layers. Finally, aspirate 5 mL of the top organic layer into a container pre-filled with 0.23 g of... The C18 (end-capped) adsorbent was thoroughly mixed in a QuEChERS purification tube at 2850 rpm for 2.5 min using a vortex mixer, followed by centrifugation at 6000 rpm for 5 min. 2 mL of the supernatant was collected, filtered through a 0.22 μm nylon membrane, and then subjected to high-performance liquid chromatography (HPLC). Specific HPLC detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016, "National Food Safety Standard - Determination of Nine Antioxidants in Food". The recoveries of THBP and BHT in each experimental group, as well as the residual oil content per milliliter of the obtained extract, were calculated. The results are shown in Table 7.

[0154] Table 7

[0155]

[0156]

[0157] As shown in Table 7, the particle size of the solid silica adsorbent must be equal to or finer than 20 mesh to ensure a recovery rate of THBP and BHT greater than 70% while achieving a residual oil content of less than 1.5 mg / mL in the extract. More preferably, a particle size of 30 mesh or finer is required to ensure a recovery rate of THBP and BHT greater than 80% while achieving a residual oil content of less than 1.0 mg / mL in the extract. While the residual oil content in the extract remains below 1.0 mg / mL as the particle size of the solid silica adsorbent decreases, when the particle size is finer than 160 mesh, it becomes impossible to guarantee a recovery rate of THBP and BHT greater than 70%. More preferably, when the particle size is finer than 120 mesh, it becomes impossible to guarantee a recovery rate of THBP and BHT greater than 80%. Therefore, the mesh size range of the solid particles in the solid extraction adsorbent is 20 to 160, and the preferred mesh size range is 30 to 120.

[0158] Example 14

[0159] Oil sample: liquid edible tea seed oil (with known concentrations of PG and OG added);

[0160] Oil sample dissolving solution: Solvent A (isobutyl butyrate): Solvent B (ethanol) = 3:2;

[0161] Extraction solution: N,N-dimethylformamide (containing 1.3% acetic acid and 0.05% lipoic acid);

[0162] Weigh 2.0 g (approximately 1 mL) of the oil sample and dissolve it completely in 5 mL of oil sample dissolving solution. Take 12 different reaction containers, each containing 10 g of sea sand (80-100 mesh). Then, add 0.2 mL, 0.5 mL, 1.0 mL, 1.5 mL, 2 mL, 2.5 mL, 3.0 mL, 3.5 mL, 4.0 mL, 4.5 mL, 5.0 mL, and 5.5 mL of the oil sample solution to each of the 12 reaction containers, respectively. After standing at room temperature for 7.5 min, 12.5 mL of extract was added, and the mixture was immediately vortexed at 2950 rpm for 70 s. Then, it was immediately centrifuged at 5000 rpm for 5 min to separate the layers. 5 mL of the uppermost organic solution was then transferred to a QuEChERS purification tube pre-loaded with 0.18 g of C18 (end-capped) adsorbent. The mixture was vortexed at 2650 rpm for 3 min, and then centrifuged again at 6000 rpm for 5 min. 2 mL of the supernatant was collected, filtered through a 0.22 μm nylon filter, and then analyzed by liquid chromatography (LC). Specific LC detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016 "National Food Safety Standard - Determination of Nine Antioxidants in Food". The recoveries of PG and OG, and the residual oil content per mL of the extract were calculated for each experimental group. The results are shown in Table 8.

[0163] Table 8

[0164]

[0165] As shown in Table 8, when the volume of the oil sample solution added to 10g of solid adsorbent is greater than 1.0mL, the recovery rates of PG and OG reach over 70%, while the residual oil content in the extract is less than 1.0mg / mL. However, with further increasing the volume of the oil sample solution added, when the volume of the oil sample solution added to 10g of solid adsorbent is greater than 4.0mL, the recovery rates of PG and OG fall below 70%, and the residual oil content in the extract is greater than 1.5mg / mL. More preferably, when the volume of the oil sample solution added to 10g of solid adsorbent is between 2.0mL and 3.0mL, the recovery rates of PG and OG reach over 80%, while the residual oil content in the extract is less than 1.0mg / mL. Therefore, the volume of the oil sample solution added to each 10g of solid extraction adsorbent should be 1.0 to 4.0mL, preferably 2.0 to 3.0mL.

[0166] Example 15

[0167] Oil sample: liquid edible oil extracted from peanut butter (with known concentrations of IAG and Ionox-100 added);

[0168] Oil sample dissolving solution: Solvent A (ethyl propionate: isopropyl ether = 5:2): Solvent B (methanol) = 5:2;

[0169] Extraction solution: ethanol:propionitrile = 9:1 (containing 0.8% formic acid and 0.10% lipoic acid);

[0170] Weigh 0.8 g (approximately 0.8 mL) of the oil sample and completely dissolve it in 2.2 mL of oil sample dissolving solution to form an oil sample solution. Take nine different reaction vessels, each containing 10 g of rock sand (100-130 mesh). Then, add 3 mL of the oil sample solution to each vessel and allow them to stand at room temperature for 0.5 min, 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, and 8 min, respectively. After adding 7.0 mL of extraction solution, immediately vortex at 3000 rpm for 75 s to mix thoroughly. Then, immediately centrifuge at 5000 rpm for 5 min to separate the layers. Finally, take 6 mL of the uppermost organic solution into a container pre-filled with 0.27 g of... The C18 (terminated) adsorbent was thoroughly mixed in a QuEChERS purification tube at 3000 rpm for 3.5 min using a vortex mixer, followed by centrifugation at 6000 rpm for 5 min. 2 mL of the supernatant was collected, filtered through a 0.22 μm nylon membrane, and then subjected to high-performance liquid chromatography (HPLC). Specific HPLC detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016, "National Food Safety Standard - Determination of Nine Antioxidants in Food". The recoveries of IAG and Ionox-100 for each experimental group were calculated, and the results are shown in Table 9.

[0171] Table 9

[0172]

[0173] As shown in Table 9, the recovery rates of IAG and Ionox-100 are greater than 70% only when the standing time at room temperature is greater than or equal to 3 minutes. More preferably, the recovery rates of IAG and Ionox-100 are greater than 90% when the standing time at room temperature is greater than or equal to 3 minutes. If the standing time at room temperature is further extended, the recovery rates of IAG and Ionox-100 will not increase significantly, but will remain at a stable level above 90%. Therefore, after adding a certain volume of oil sample solution to the solid extraction adsorbent, it should be allowed to stand at room temperature for at least 3 minutes, preferably at least 5 minutes.

[0174] Example 16

[0175] Oil sample: liquid edible blended oil (with known concentrations of TBHQ and BHT added);

[0176] Oil sample dissolving solution: Solvent A (chloroform): Solvent B (acetonitrile) = 2:1;

[0177] Extraction solution: Acetonitrile: Methanol = 5:1 (containing 1.8% acetic acid and 0.22% sesamin);

[0178] Weigh 1.5g (approximately 1.5mL) of the oil sample and dissolve it completely in 3.5mL of oil sample dissolving solution. Take 12 different reaction vessels, each containing 20g of fine sand (120-150 mesh). Add 5mL of the oil sample solution to each vessel and let them stand at room temperature for 6 minutes. Then add 9.0mL of extraction solution to each vessel and immediately vortex at 3000rpm for 8s, 15s, 30s, 45s, 60s, 75s, 90s, 105s, 120s, 135s, 150s, and 165s. Immediately afterward, centrifuge at 4400rpm for 5 minutes to separate the layers. Then, take 7mL of the uppermost organic solution into a pre-filled container containing 0.29g of... In a QuEChERS purification tube containing C18 (end-capped) adsorbent, the mixture was thoroughly shaken and mixed at 3000 rpm for 3.0 min on a vortex mixer. Then, it was centrifuged again at 6000 rpm for 5 min. 2 mL of the supernatant was collected, filtered through a 0.22 μm nylon filter, and then subjected to liquid chromatography (LC). Specific LC detection conditions were performed according to the relevant technical requirements of GB 5009.32-2016, "National Food Safety Standard - Determination of Nine Antioxidants in Food". The recoveries of TBHQ and BHT for each experimental group were calculated, and the results are shown in Table 10.

[0179] Table 10

[0180]

[0181]

[0182] As shown in Table 10, the recovery rates of TBHQ and BHT are greater than 70% only when the shaking and mixing reaction time is within the range of 30–120 s; more preferably, the recovery rates are greater than 80% only when the shaking and mixing reaction time is within the range of 45–90 s; and most preferably, the recovery rates are greater than 90% only when the shaking and mixing reaction time is within the range of 60–75 s. Therefore, by fully shaking and mixing extraction, the synthetic antioxidants in the oil sample solution that has been fully dispersed and coated on the surface of the solid phase particles of the extraction adsorbent are extracted using the extraction liquid. The shaking and mixing time is 30–120 s, preferably 45–90 s, and more preferably 60–75 s.

[0183] Example 17

[0184] Oil sample: liquid edible oil extracted from fried dough twists (with known concentrations of NDGA and DG added);

[0185] Oil sample solution: composed of solvent A (isopropyl acetate) and solvent B (ethanol) in different proportions, and the content (volume) of solvent B in the oil sample solution is in the range of 30% to 40%.

[0186] Extraction solution: acetonitrile (containing 0.9% acetic acid and 0.28% sesamin);

[0187] Weigh 0.2g to 1.5g (approximately 0.2mL to 1.5mL) of the oil sample, and completely dissolve it in 2 to 10 times its volume of oil sample dissolving solution to form an oil sample solution. Take 9 different reaction containers, each containing 10g to 20g of fine sand (120-150 mesh). Then, add 2mL to 6mL of oil sample solution to each reaction container. After standing at room temperature for 5.5 minutes, add different volumes of extract solution. Thus, the proportion of solvent A in the oil sample dissolving solution used in each reaction container, by volume percentage, is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, and 45% of the total volume of oil sample dissolving solution and extract solution used in the reaction, respectively. Immediately after mixing, the samples were thoroughly shaken at 2900 rpm for 75 seconds on a vortex mixer. Then, they were centrifuged at 4100 rpm for 5 minutes to separate the layers. 4 mL of the top organic solution was then transferred to a QuEChERS purification tube pre-loaded with 0.19 g of C18 (end-capped) adsorbent. The mixture was then thoroughly shaken at 2900 rpm for 3.0 minutes on a vortex mixer. After centrifugation at 6000 rpm for 5 minutes, 2 mL of the supernatant was collected. The amount of residual oil in the extract obtained from each group of experiments was measured. The results are shown in Table 11.

[0188] Table 11

[0189]

[0190]

[0191] As shown in Table 11, when the proportion (%) of solvent A in the total volume of the oil sample solution and extract used in the reaction exceeds 30%, the residual oil content in the obtained extract increases significantly. Only when this proportion (%) is less than or equal to 30% is the residual oil content in the obtained extract less than 2.5 mg / mL; more preferably, when this proportion (%) is less than or equal to 20%, the residual oil content in the obtained extract is less than 1.5 mg / mL; most preferably, when this proportion (%) is less than or equal to 15%, the residual oil content in the obtained extract is less than 1.0 mg / mL. Therefore, the proportion of solvent A in the oil sample solution used in each extraction experiment in the total volume of the oil sample solution and extract used in each extraction experiment ranges from 30% to 5%, preferably 20% to 5%, and more preferably 15% to 5%.

[0192] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for separating multiple synthetic antioxidants from edible oils, characterized in that, Includes the following steps: Step 1: Dissolve and dilute the oil sample with an oil sample dissolving solution to obtain an oil sample solution; Step 2: Mix the oil sample solution obtained in Step 1 with a solid extraction adsorbent, then add an extraction solution for mixing and extraction to obtain a reaction mixture; the solid extraction adsorbent is silica particles, wherein the silica content is greater than 99.5%; Step 3: Centrifuge, the reaction mixture separates into three layers, take the uppermost layer solution, and add a matrix dispersion solid phase extraction (QuEChERS) purification tube containing a purification adsorbent for purification treatment to obtain a solution containing multiple synthetic antioxidants; the oil sample dissolving solution includes solvent A and solvent B; solvent A is an organic solvent, miscible with the extraction solution, and the solubility of the oil sample in solvent A is ≥2.0 g / 100 g solvent A; the solution Agent B is an organic solvent, miscible with the extract and solvent A. The solubility of the synthetic antioxidant in solvent B is ≥0.10g / 100g solvent B. For oil samples that are liquid at room temperature, solvent B is immiscible with the oil sample. For oil samples that are solid at room temperature, solvent B may or may not be miscible with the oil sample. For oil samples that are liquid at room temperature, the volume of solvent B accounts for 20%~50% of the total volume of the oil sample solution. For oil samples that are solid at room temperature, the volume of solvent B accounts for 30%~70% of the total volume of the oil sample solution. The solubility of the synthetic antioxidant in the extract is ≥0.10g / 100g extract, and the solubility of the oil sample is ≤1.0g / 100g extract.

2. The method for separating multiple synthetic antioxidants from edible oils as described in claim 1, characterized in that, For grease samples that are liquid at room temperature, the volume of solvent B accounts for 30% to 40% of the total volume of the grease sample solution; for grease samples that are solid at room temperature, the volume of solvent B accounts for 40% to 60% of the total volume of the grease sample solution.

3. The method for separating multiple synthetic antioxidants from edible oils as described in claim 1, characterized in that, Includes one or more of the following features: (1) the volume ratio of the oil sample solution to the oil sample is 2~20:1; (2) the volume ratio of the extract to the oil sample is 2~10:1; (3) the silica particles are natural, rough-surfaced fine sand; the mesh size of the silica particles is 20~160; (4) the purification adsorbent is a C18 end-capped adsorbent.

4. The method for separating multiple synthetic antioxidants from edible oils as described in claim 1, characterized in that, Includes one or more of the following characteristics: i) In step two, to ensure that the oil sample solution is fully dispersed and coated on the solid phase particle surface of the solid extraction adsorbent, two conditions need to be met: 1) The volume of the oil sample solution added to each 10g of the solid extraction adsorbent is 1.0~4.0 mL; 2) After adding the oil sample solution to the solid extraction adsorbent, it is allowed to stand at room temperature for a standing time of ≥3 min; ii) The mixing extraction in step two is carried out by vortex oscillation, specifically by vortex oscillation at 2000~3500 rpm for 30~120 s to fully mix and react; iii) The centrifugation in step three is high-speed centrifugation at 4000~10000 rpm; iv) The purification treatment in step three is carried out by vortex oscillation, specifically by vortex oscillation at 2000~3000 rpm for 1~5 min to fully mix and react.

5. The method for separating multiple synthetic antioxidants from edible oils as described in claim 1, characterized in that, The oil sample solution and the extract satisfy the following relationship: the volume percentage of solvent A in the oil sample solution used for a single extraction is 30% to 5% of the total volume of the oil sample solution and the extract.

6. The method for separating multiple synthetic antioxidants from edible oils as described in claim 1, characterized in that, The synthetic antioxidants include any one or more of tert-butylhydroquinone, propyl gallate, octyl gallate, dodecyl gallate, 2,6-di-tert-butyl-4-hydroxymethylphenol, 4-hexylresorcinol, pentyl gallate, 2,4,5-trihydroxyphenylbutanone, nordihydroguaiacol, tert-butylhydroanisole, 2,6-di-tert-butyl-4-methylphenol, and ethoxyquinoline.

7. The method for separating multiple synthetic antioxidants from edible oils as described in claim 1, characterized in that, Includes any one of the following characteristics: a) For oil samples that are liquid at room temperature, solvent A is selected from one or more of chlorinated hydrocarbon solvents, ester solvents, or ether solvents; solvent B is selected from one or more of methanol, ethanol, acetonitrile, and propionitrile; b) For oil samples that are solid at room temperature, solvent A is selected from one or more of chlorinated hydrocarbon solvents, ester solvents, ether solvents, or aromatic hydrocarbon solvents; solvent B is selected from one or more of aromatic hydrocarbon solvents and acetonitrile.

8. The method for separating multiple synthetic antioxidants from edible oils as described in claim 7, characterized in that, Includes any one of the following characteristics: (a1) For oil samples that are liquid at room temperature, solvent A is selected from one or more of dichloromethane, trichloromethane, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl propionate, ethyl propionate, butyl propionate, amyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, amyl butyrate, diethyl ether, propyl ether, isopropyl ether, methyl butyl ether, and tetrahydrofuran; (b1) For oil samples that are solid at room temperature, solvent A is selected from one or more of dichloromethane, trichloroethane, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, ethyl formate, propyl formate, butyl butyrate, methyl butyrate, ethyl butyrate, ethyl butyrate, ethyl butyrate, ethyl butyrate, diethyl butyrate, propyl butyrate, butyl butyrate, and tetrahydrofuran; The solvent B is selected from one or more of chloromethane, trichloromethane, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl propionate, ethyl propionate, butyl propionate, amyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, butyl butyrate, amyl butyrate, diethyl ether, propyl ether, isopropyl ether, methyl butyl ether, tetrahydrofuran, benzene, toluene, xylene, and trimethylbenzene; and solvent B is selected from one or more of benzene, toluene, xylene, trimethylbenzene, and acetonitrile, and solvent B does not contain the same components as solvent A.

9. The method for separating multiple synthetic antioxidants from edible oils as described in claim 1, characterized in that, It includes one or more of the following characteristics: 1) The extract is selected from one or more of methanol, ethanol, acetonitrile, N,N-dimethylformamide, N,N-diethylformamide, and N,N-dimethylacetamide; 2) The extract contains acetic acid or formic acid; the volume fraction of the acetic acid or formic acid is 0.05% to 2%; 3) The extract contains lipoic acid or sesamol; the proportion of the lipoic acid is 0.01wt% to 0.10wt%; or the proportion of the sesamol is 0.1wt% to 0.5wt%.

10. The method for separating multiple synthetic antioxidants from edible oils as described in any one of claims 1 to 9 is used in the detection of antioxidant content in edible oils.

11. The sample pretreatment method package used in the method for separating multiple synthetic antioxidants from edible oils as described in any one of claims 1 to 9, the method package comprising the following four parts: an oil sample dissolution solution, an extraction solution, a solid extraction adsorbent, and a matrix dispersion solid phase extraction (QuEChERS) purification tube containing a purification adsorbent.

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