A method for removing 3-mcpd by adsorption with amino-silica

Abstract

The application provides a method for removing 3-MCPD by using aminosilica adsorption. The method comprises the following steps: adsorbing a solution containing 3-MCPD by using aminosilica, mixing, adding a NaHCO3 solution to adjust the pH value to 7.0-9.0, reacting under the condition of 60-100 DEG C for 2-10 min, cooling to room temperature, mixing the mixed solution, and removing aminosilica particles by centrifugation. The aminosilica is an inorganic chemical material, which is an amorphous white powder, has the characteristics of non-toxicity, non-odor and non-pollution, is simple and easy to obtain, and has low cost. The aminosilica can be generated in batches, and has high adsorption efficiency for 3-MCPD and simple operation.

Description

Technical Field

[0001] This invention relates to a detection method, and more particularly to a method for removing 3-MCPD by adsorption of amino silica and its application in the detection of 3-MCPD. Background Technology

[0002] 3-MCPD exhibits extremely significant nephrotoxicity and high genotoxicity, and has been strictly classified as a Group 2B carcinogen by the International Agency for Research on Cancer (IARC) Working Group. It is well known that 3-MCPD is a food processing contaminant formed by the reaction of triacylglycerols, phospholipids, or glycerols in fatty or fatty foods with hydrochloric acid, and subsequent heating. High-temperature, prolonged heating in the presence of hydrochloric acid (HCl) is considered the cause of 3-MCPD formation in the presence of glycerol, lecithin, and other glycerols or 3-MCPD esters from other sources. The presence of chloride ions is also important for the formation of 3-MCPD and its isomers. Since 3-MCPD is present in a variety of foods, selecting a material for adsorbing and removing 3-MCPD is imperative.

[0003] Currently, there are many methods for removing 3-MCPD by adsorption, including precipitation, electrochemical, biochemical, and physical adsorption methods. These methods can solve high concentrations of 3-MCPD pollution, but they are time-consuming, energy-intensive, and wasteful of resources. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a method for removing 3-MCPD by adsorption using amino silica. Under alkaline conditions, the chloride ions of 3-MCPD can react with the amino groups of amino silica, resulting in modified silica having a strong ability to adsorb 3-MCPD, which is then applied to the adsorption and removal of 3-MCPD.

[0005] To achieve the above-mentioned technical objectives, the present invention provides a method for removing 3-MCPD by adsorption of amino silica, characterized in that the specific steps of the method are as follows: amino silica is added to a sample solution containing 3-MCPD and mixed, wherein the ratio of amino silica to 3-MCPD in the sample solution is 4-8 mg: 1.2-2.4 μg; NaHCO3 solution is added to adjust the pH value to 7.0-9.0, and the mixture is reacted at a temperature of 60-100°C for 2-10 min. After cooling to room temperature, the mixture is mixed and centrifuged, and the supernatant is taken as the sample solution with amino silica removed.

[0006] A further technical solution of the present invention: The amino silica is obtained by adding SiO2 nanoparticles to an ethanol solution containing 3-aminopropyltriethoxysilane and reacting at 45℃~50℃ for 24 h~48 h, wherein the concentration of 3-aminopropyltriethoxysilane in the ethanol solution is 3%~6%; after the reaction, the synthesized material is washed with distilled water and ethanol to remove unreacted 3-aminopropyltriethoxysilane, and then dried under vacuum for 22~26 h to obtain amino silica particles.

[0007] A further technical solution of the present invention: the method further includes detecting the content of 3-MCPD in the treated sample solution, the specific process of which is as follows:

[0008] (1) The standard curve equation of 3-MCPD concentration c versus peak area S was prepared as follows: 3-MCPD standard solutions of different concentrations were prepared and detected by gas chromatography-mass spectrometry to obtain the corresponding peak area values ​​of 3-MCPD standard solutions of different concentrations; the peak area values ​​of the standard solutions and the concentration of 3-MCPD were linearly fitted to obtain the standard curve equation of the relationship between peak area value S and 3-MCPD concentration c: S = 163865c + 577.49;

[0009] (2) The peak area of ​​the treated sample solution is obtained by gas chromatography-mass spectrometry, and the peak area value S of the treated sample solution is substituted into the standard curve equation in step (2) to calculate the concentration of 3-MCPD in the treated sample solution.

[0010] The preferred technical solution of this invention is as follows: the sample solution containing 3-MCPD is soy sauce; before removing 3-MCPD, the soy sauce is pretreated as follows: the finished soy sauce is mixed with a 5 mol / L NaCl solution at a mass-to-volume ratio of 2 g:3 mL, loaded onto a solid-phase extraction column, eluted first with a hexane-ethyl ether mixture, then eluted with ether, the ether eluent is collected and the solvent is removed, water is added and the mixture is shaken evenly in a centrifuge tube to obtain the soy sauce sample detection solution; wherein the hexane-ethyl ether mixture is prepared by mixing at a volume ratio of 9:1; the mass-to-volume ratio of soy sauce to hexane-ethyl ether mixture is 1 g:10 mL; the mass-to-volume ratio of soy sauce to ether is 2 g:75 mL; the mass-to-volume ratio of soy sauce to water is 1 g:0.25 mL.

[0011] The preferred technical solution of the present invention is as follows: the mass ratio of the aminated silica to the 3-MCPD in the sample solution containing 3-MCPD is 4.0 mg:1.2 ug; the pH value is adjusted to 8.5 by adding NaHCO3 solution, reacted in a sand bath at 90℃ for 8 min, cooled to room temperature, the mixture is mixed and centrifuged, and the supernatant is taken for gas chromatography-mass spectrometry detection.

[0012] A preferred technical solution of the present invention is as follows: five 3-MCPD standard solutions are prepared with concentrations of 0.01, 0.05, 0.1, 0.2, and 0.4 mg∙L, respectively. -1 The peak areas corresponding to the five 3-MCPD standard solutions were 3066.6, 7892, 15769.5, 35021.4, and 65675, respectively. The peak area values ​​of the standard solutions and the concentration of 3-MCPD were linearly fitted to obtain the standard curve equation of the relationship between the peak area value S and the concentration of 3-MCPD c.

[0013] In this invention, under alkaline conditions, the chloride ions of 3-MCPD can react with the amino groups of amino silica. Experiments show that the modified silica has a strong ability to adsorb 3-MCPD and can complete the adsorption and removal of 3-chloro-1,2-propanediol.

[0014] The amino silica in this invention is synthesized from 3-aminopropyltriethoxysilane (APTES) and silica. 3-aminopropyltriethoxysilane (APTES) is directly modified and grafted onto the surface of hierarchical mesoporous silica. Due to the large surface area and amino functional groups of hierarchical mesoporous silica, under alkaline conditions, the chloride ions of 3-MCPD can react with the amino groups of amino silica, so that the modified silica has a strong ability to adsorb 3-MCPD.

[0015] The method for synthesizing amino silica in this invention is simple, easy to produce, environmentally friendly, and produces no secondary pollution. Using modified silica as an adsorbent material has high efficiency, simple operation, easy material preparation, and is environmentally friendly; it can be widely used in the adsorption and detection of 3-MCPD. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the synthesis of aminosilica in this invention;

[0017] Figure 2 This is a schematic diagram of the adsorption reaction principle in this invention;

[0018] Figure 3 This is a scanning electron microscope image of the amino silica synthesized in Experiment 1;

[0019] Figure 4This is the adsorption isotherm of 3-MCPD on amino silica in Experiment 2;

[0020] Figure 5 This refers to the effect of reaction pH on the adsorption of 3-MCPD in Experiment 3;

[0021] Figure 6 This refers to the effect of reaction temperature on the adsorption of 3-MCPD in Experiment 4;

[0022] Figure 7 This refers to the effect of reaction time on 3-MCPD adsorption in Experiment 5;

[0023] Figure 8 is a standard curve showing the linear relationship between 3-MCPD concentration and peak area. Detailed Implementation Plan

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments. The technical solutions shown in the drawings are specific embodiments of the present invention and are not intended to limit the scope of the claimed invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] This invention provides a method for removing 3-MCPD by adsorption of amino silica; the method includes, in sequence, the synthesis of amino silica, the preparation of a standard curve equation of 3-MCPD concentration c versus peak area S, the adsorption of 3-MCPD by amino silica, the detection of the peak area of ​​the test solution by gas chromatography-mass spectrometry, and the calculation of the concentration of 3-MCPD in the test sample after adsorption by substituting the detected peak area value S into the above standard curve equation.

[0026] The detection principle of this invention is as follows: Figure 2 As shown, 3-MCPD readily reacts with the amino groups of amino silica in alkaline solution by substituting chlorine atoms; therefore, the concentration of 3-MCPD can be directly measured by gas chromatography-mass spectrometry.

[0027] Experiment 1: Synthesis of Aminosilica:

[0028] Commercially available SiO2 nanoparticles were added to an ethanol solution containing 3% 3-aminopropyltriethoxysilane (APTES) and reacted at 45°C for 24 h. After the reaction, the synthesized material was washed with distilled water and ethanol to remove unreacted APTES, and then dried under vacuum for 24 h to obtain aminosilica. The synthesis reaction is as follows: Figure 1As shown. A certain amount of amino silica prepared by the above method was weighed, and its negative charge was reduced by sputtering gold onto the sample. The observation area was located and selected using a scanning electron microscope at 500x magnification, and the microscopic features of the sample were observed at 10kx magnification. The scanning electron microscope image of the synthesized amino silica is shown below. Figure 3 As shown.

[0029] Experiment 2: An adsorption isotherm experiment was conducted on the amino silica synthesized in Experiment 1.

[0030] Accurately weigh 4.0 mg of aminated silica into 10 mL centrifuge tubes, and add 0.01, 0.05, 0.1, 0.2, and 0.4 mg∙L⁻¹ respectively. -1 Add 3 mL of 3-MCPD solution and adjust the pH to 9.0 with NaHCO3 solution. React at 100℃ for 10 min. After cooling to room temperature, mix the solution thoroughly and centrifuge. Perform gas chromatography-mass spectrometry (GC-MS) on the supernatant. Simultaneously, accurately weigh 4.0 mg of silica into 10 mL centrifuge tubes and add 0.01, 0.05, 0.1, 0.2, and 0.4 mg∙L⁻¹ of different concentrations. -1 Add 3 mL of 3-MCPD solution and adjust the pH to 9.0 with NaHCO3 solution. React at 100℃ for 10 min. After cooling to room temperature, mix the solution thoroughly, centrifuge, and collect the supernatant for gas chromatography-mass spectrometry (GC-MS). Compare the adsorption isotherms from the two analyses. (Specific details are as follows...) Figure 4 As shown, through Figure 4 It can be seen that amino silica has a better adsorption effect on 3-MCPD than silica.

[0031] Experiment 3: Selecting the optimal pH for amino silica adsorption of 3-MCPD:

[0032] Take five 10 mL centrifuge tubes and number them 1, 2, 3, 4, and 5. Accurately weigh 4.0 mg of aminated silica into each 10 mL centrifuge tube and add 0.4 mg·L⁻¹. -1 3 mL of 3-MCPD solution was added, and NaHCO3 solution was added to adjust the pH to 7.0, 7.5, 8.0, 8.5, and 9.0 respectively. The mixture was reacted at 100℃ for 10 min. After cooling to room temperature, the mixture was thoroughly mixed and centrifuged. The supernatant was then analyzed by gas chromatography-mass spectrometry. The results are as follows: Figure 5 As shown, through Figure 5 It can be seen that the adsorption capacity reaches its maximum at pH=8.5, which is 0.090 mg / g.

[0033] Experiment 4: Selecting the optimal temperature for the adsorption of 3-MCPD by amino silica:

[0034] Take five 10 mL centrifuge tubes and number them 1, 2, 3, 4, and 5. Accurately weigh 4.0 mg of aminated silica into each 10 mL centrifuge tube and add 0.4 mg·L⁻¹. -1 3 mL of 3-MCPD solution was added, and the pH was adjusted to 8.5 with NaHCO3 solution. The mixtures were reacted at 60℃, 70℃, 80℃, 90℃, and 100℃ for 10 min each. After cooling to room temperature, the mixtures were thoroughly mixed and centrifuged. The supernatant was then analyzed by gas chromatography-mass spectrometry (GC-MS). The results are shown below. Figure 6 As shown, Figure 6 As shown, the adsorption capacity reaches its maximum of 0.095 mg / g at a temperature of 90℃, and remains essentially unchanged when the temperature is above 90℃.

[0035] Experiment 5: Selecting the optimal time for amino silica to adsorb 3-MCPD:

[0036] Take five 10 mL centrifuge tubes and number them 1, 2, 3, 4, and 5. Accurately weigh 4.0 mg of aminated silica into each 10 mL centrifuge tube and add 0.4 mg·L⁻¹. -1 3 mL of 3-MCPD solution was added, and the pH was adjusted to 8.5 with NaHCO3 solution. The mixture was reacted at 90℃ for 2 min, 4 min, 6 min, 8 min, and 10 min respectively. After cooling to room temperature, the mixture was thoroughly mixed and centrifuged. The supernatant was then analyzed by gas chromatography-mass spectrometry. The detection results are as follows: Figure 7 As shown, through Figure 7 It can be seen that the adsorption capacity reaches its maximum of 0.11 mg / g when the reaction time reaches 10 min.

[0037] The present invention will be further illustrated below with reference to the embodiments. The standard curves for the linear relationship between 3-MCPD concentration and peak area in the following embodiments are prepared as follows:

[0038] a. First, prepare five 3-MCPD standard solutions with concentrations of 0.01, 0.05, 0.1, 0.2, and 0.4 mg∙L⁻¹. -1 ;

[0039] b. Five 3-MCPD standard solutions of different concentrations were placed in centrifuge tubes and detected by gas chromatography-mass spectrometry. The peak areas of the five 3-MCPD standard solutions were 3066.6, 7892, 15769.5, 35021.4 and 65675, respectively.

[0040] c. Perform linear fitting between the measured peak area values ​​of the standard solution and the concentration of 3-MCPD, such as... Figure 7As shown, the final standard curve equation relating the peak area S to the 3-MCPD concentration c is: S = 163865c + 577.49.

[0041] Example 1: Soy sauce samples were processed as follows and then analyzed by gas chromatography-mass spectrometry (GC-MS). The processing procedure was as follows: Finished soy sauce was mixed with a 5 mol / L NaCl solution at a mass-to-volume ratio of 2 g:3 mL, loaded onto a solid-phase extraction column, and eluted first with a hexane-ethyl ether mixture, then with ether. The ether eluent was collected, the solvent was removed, and water was added to a centrifuge tube and shaken thoroughly to obtain the soy sauce sample detection solution. The hexane-ethyl ether mixture was prepared at a volume ratio of 9:1; the mass-to-volume ratio of soy sauce to the hexane-ethyl ether mixture was 1 g:10 mL; the mass-to-volume ratio of soy sauce to ether was 2 g:75 mL; and the mass-to-volume ratio of soy sauce to water was 1 g:0.25 mL. The sample was then concentrated to approximately 2 mL using a nitrogen nebulizer, filtered through a 0.2 μm filter membrane, and analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the concentration of 3-MCPD in the sample was 0.85 mg / L.

[0042] Simultaneously, 2 mL of the pretreated soy sauce sample was added with 2 mg of aminated silica, and the pH was adjusted to 8.5 with NaHCO3 solution. The mixture was then placed in a 90℃ sand bath for 8 min. After cooling to room temperature, the mixture was thoroughly mixed and centrifuged. The supernatant was then analyzed by gas chromatography-mass spectrometry. The peak area value S of the sample solution was found to be 90703.24. Substituting this into the equation S = 163865c + 577.49, the concentration of 3-MCPD in the treated soy sauce was calculated to be 0.55 mg / L.

[0043] After treatment by the method of the present invention, the concentration of 3-MCPD in soy sauce decreased, indicating that the method of the present invention is effective in adsorbing 3-MCPD in soy sauce. According to the conversion in the examples, when 2 ml of sample was adsorbed, 2 mg of amino silica adsorbed 0.6 μg of 3-MCPD, which showed good adsorption effect.

[0044] This invention establishes a simple, effective, convenient, non-toxic, environmentally friendly, and highly sensitive adsorption and removal method for 3-MCPD, based on the fact that 3-MCPD readily reacts with the amino groups of amino silica in alkaline solution by substituting chlorine atoms.

[0045] The above description is merely one embodiment of the present invention, and while it is detailed and specific, it should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for removing 3-MCPD by adsorption using amino silica, characterized in that, The specific steps of the method are as follows: Amino silica is added to a sample solution containing 3-MCPD and mixed. The ratio of amino silica to 3-MCPD in the sample solution is 4–8 mg: 1.2–2.4 μg. NaHCO3 solution is added to adjust the pH to 8.5, and the mixture is reacted at 90°C for 10 min. After cooling to room temperature, the mixture is homogenized, centrifuged, and the supernatant is obtained as the sample solution after removing amino silica. The amino silica is obtained by adding SiO2 nanoparticles to an ethanol solution containing 3-aminopropyltriethoxysilane and reacting at 45°C–50°C for 24–48 h. The concentration of 3-aminopropyltriethoxysilane in the ethanol solution is 3%–6%. After the reaction, the synthesized material is rinsed with distilled water and ethanol to remove unreacted 3-aminopropyltriethoxysilane, and then dried under vacuum for 22–26 h to obtain amino silica particles. The sample solution containing 3-MCPD was soy sauce. Before removing 3-MCPD, the soy sauce was pretreated as follows: The finished soy sauce was mixed with a 5 mol / L NaCl solution at a mass-to-volume ratio of 2 g:3 mL, loaded onto a solid-phase extraction column, and eluted first with a hexane-ethyl ether mixture, then with ether. The ether eluent was collected, the solvent removed, and water was added to a centrifuge tube and shaken until homogeneous to obtain the soy sauce sample detection solution. The hexane-ethyl ether mixture was prepared at a volume ratio of 9:1; the mass-to-volume ratio of soy sauce to the hexane-ethyl ether mixture was 1 g:10 mL; the mass-to-volume ratio of soy sauce to ether was 2 g:75 mL; and the mass-to-volume ratio of soy sauce to water was 1 g:0.25 mL.

2. The method for removing 3-MCPD by adsorption using amino silica according to claim 1, characterized in that... The method also includes detecting the content of 3-MCPD in the treated sample solution, the specific process of which is as follows: (1) The standard curve equation of 3-MCPD concentration c versus peak area S was prepared as follows: 3-MCPD standard solutions of different concentrations were prepared and detected by gas chromatography-mass spectrometry to obtain the corresponding peak area values ​​of 3-MCPD standard solutions of different concentrations; the peak area values ​​of the standard solutions and the concentration of 3-MCPD were linearly fitted to obtain the standard curve equation of the relationship between peak area value S and 3-MCPD concentration c: S = 163865c + 577.49; (2) The peak area of ​​the treated sample solution is obtained by gas chromatography-mass spectrometry, and the peak area value S of the treated sample solution is substituted into the standard curve equation in step (2) to calculate the concentration of 3-MCPD in the treated sample solution.

3. The method for removing 3-MCPD by adsorption using amino silica according to claim 2, characterized in that: Five 3-MCPD standard solutions were prepared with concentrations of 0.01, 0.05, 0.1, 0.2, and 0.4 mg∙L⁻¹. -1 The peak areas corresponding to the five 3-MCPD standard solutions were 3066.6, 7892, 15769.5, 35021.4, and 65675, respectively. The peak area values ​​of the standard solutions and the concentration of 3-MCPD were linearly fitted to obtain the standard curve equation of the relationship between the peak area value S and the concentration of 3-MCPD c.

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