Solid phase extractant preparation method and extraction detection method for o-phenyl esters

Abstract

The present invention relates to the technical field of solid-phase extractant preparation, and discloses a solid-phase extractant preparation method and an extraction detection method for o-phenyl esters. The solid-phase extractant preparation method comprises the following steps: S1, grinding tobacco stems to obtain coarse stem powder; S2, heating the coarse stem powder in a water bath, wherein the water bath heating treatment includes the step of heating the coarse stem powder in a water bath using a strong alkaline solution; S3, transferring the coarse stem powder that has completed the water bath heating treatment to an extractor to remove grease impurities in the coarse stem powder and thereby obtain a crude extractant product; and S4, washing and drying the crude extractant product in sequence to obtain a solid-phase extractant. The solid-phase extractant prepared using the solid-phase extractant preparation method of the present invention has the dual advantages of low raw materials and low preparation cost, can replace expensive octadecyl silica gel solid-phase extractant, effectively adsorb hydrophobic o-phenyl ester compounds, and reduce the batch solid-phase extraction detection cost of o-phenyl esters.

Description

Technical Field

[0001] The invention relates to the technical field of solid phase extractant preparation, in particular to a solid phase extractant preparation method and an extraction and detection method for o-phenyl esters. Background Art

[0002] o-Phenyl esters are a common class of organic compounds found in polluted water. Detection of o-phenyl esters in contaminated water typically involves solid-phase extraction (SPE) to extract the esters from the water and then analyze the water. Octadecyl silica gel is typically used as the SPE column's SPE solvent for SPE.

[0003] However, octadecyl silica requires multiple steps, including pretreatment, silanization, and end-capping, to produce it. Furthermore, the silane coupling agents and catalysts added during the silanization reaction are expensive and used in large quantities, making the preparation of octadecyl silica complex and costly. Furthermore, during solid-phase extraction, the sample solution often contaminates the octadecyl silica, making it difficult to reuse.

[0004] When testing large-scale contaminated water bodies, it's necessary to examine the o-phenyl ester content in every area of ​​the water. This batch testing requires the use of large quantities of octadecyl silica solid-phase extraction reagents. However, the complex and expensive preparation of octadecyl silica, coupled with its difficulty in repeated reuse, significantly increases the cost of water pollution testing.

[0005] Therefore, it is very necessary to find a low-cost solid phase extraction agent and a low-cost preparation process for preparing the solid phase extraction agent. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a low-cost solid-phase extraction agent of o-phenyl esters.

[0007] To achieve the above-mentioned object, the present invention provides a method for preparing a solid-phase extractant, wherein the solid-phase extractant is made from tobacco stems, and the method for preparing the solid-phase extractant comprises the following steps: S1, grinding the tobacco stems to obtain coarse stem powder; S2, heating the coarse stem powder in a water bath to remove impurities therefrom, wherein the water bath heating treatment comprises the step of heating the coarse stem powder in a water bath using a strong alkaline solution; S3, transferring the coarse stem powder that has undergone the water bath heating treatment to an extractor to remove oil impurities in the coarse stem powder and thereby obtain a crude extractant product; and S4, washing and drying the crude extractant product in sequence to obtain a solid-phase extractant.

[0008] In some embodiments, in step S1, the particle size of the coarse stem powder is between 50-200 mesh.

[0009] In some embodiments, in step S2, the coarse stem powder is heated in a water bath while being wrapped in a filter; in step S3, the coarse stem powder is transferred to an extractor while being wrapped in a filter to remove oil impurities; wherein the filter includes multiple layers of alternating first and second filter membranes; and the innermost layer of the filter that contacts the coarse stem powder is the first filter membrane, and the filter pores of the first filter membrane are smaller than the filter pores of the second filter membrane.

[0010] In some embodiments, in step S2, the water bath heating treatment further includes the following process: wrapping the coarse stem powder in a filter, and then heating it in a water bath for the first time with pure water; wherein the pure water is high-purity water that has been purified to remove more than 90% of ions and impurities; after completing the first water bath heating, heating it in a water bath for the second time with a strong alkaline solution.

[0011] In some embodiments, during the first water bath heating treatment, the solid-liquid mass-to-volume ratio of the coarse stem powder to pure water is 1:(4~6), the heating temperature is 60-80°C, and the water bath heating time is 20-40 minutes; during the second water bath heating treatment, the solid-liquid mass-to-volume ratio of the coarse stem powder to the strong alkaline solution is 1:(4~6), the heating temperature is 40-60°C, and the water bath heating time is 2-4 hours.

[0012] In some embodiments, the solute of the strong alkaline solution can be at least one of NaOH and KOH, and the concentration of the strong alkaline solution is 0.5-2 mol / L.

[0013] In some embodiments, in step S3, the extractor is a Soxhlet extractor, and the coarse stem powder wrapped by the filter is transferred to an extraction tube of the Soxhlet extractor, the top opening of the extraction tube is connected to the condenser; pure water is added to the extraction bottle connected to the bottom of the Soxhlet extractor, and the extraction bottle is heated, the heating temperature is 100~110℃, and the heating reflux time is 3~8h.

[0014] In some embodiments, in step S4, the step of washing the crude extractant product includes: first taking out the crude extractant product and placing it in a first container filled with pure water, so that the crude extractant product is fully in contact with the pure water, and filtering the pure water mixed with the crude extractant product; transferring the crude extractant product obtained by filtration to a second container filled with methanol, repeatedly mixing it with methanol and filtering it.

[0015] In some embodiments, in step S4, the step of drying the crude extractant product includes: vacuum drying the crude extractant product obtained by filtration to obtain a solid phase extractant.

[0016] On the other hand, the present invention provides an extraction and detection method for o-phenyl esters, which uses the solid phase extractant prepared in the above embodiment and includes the following steps: (1) activating the extraction column, filling the solid phase extractant into the empty extraction column to prepare an extraction column, and activating the extraction column; (2) taking a preset amount of a sample solution containing o-phenyl ester compounds and adding it to the activated extraction column; (3) after the sample solution has passed through the column, rinsing the extraction column with quantitative pure water, eluting the extraction column with quantitative acetonitrile, and collecting the eluate; (4) drying the eluate, and then adding the dried eluate to a quantitative organic solvent for re-dissolution to obtain a liquid to be tested on the machine, and then sending the liquid to be tested on the machine to be tested in a liquid chromatography-ultraviolet detector for detection to obtain a chromatogram of the liquid to be tested on the machine.

[0017] In some embodiments, when activating the extraction column, a preset amount of solid phase extractant is loaded into an empty extraction column and compressed with a sieve plate to form an extraction column; then, a fixed amount of acetonitrile and a fixed amount of pure water are sequentially added to the extraction column to activate the extraction column.

[0018] The above technical solution of the present invention has the following beneficial effects:

[0019] The raw material used in the solid-phase extractant preparation method of the present invention is tobacco stems, discarded during tobacco leaf production. Tobacco stems are inexpensive and readily available. Furthermore, the overall preparation process is relatively simple, eliminating the need for silane coupling agents and catalysts used in the preparation of octadecyl silica gel, and eliminating the need for cumbersome processing steps such as end-capping. This significantly reduces the production cost of the solid-phase extractant. Furthermore, as a natural material, tobacco stems are renewable and environmentally friendly, facilitating resource reuse. Furthermore, the porous structure formed by the lignin and cellulose in the processed tobacco stems provides a high specific surface area, enhancing the adsorption of hydrophobic organic molecules (such as o-phenyl esters). Furthermore, the tobacco stems have multiple functional groups on their surface, such as hydroxyl and carboxyl groups, which can adsorb target compounds through mechanisms such as hydrogen bonding and electrostatic interactions. Therefore, the solid-phase extractant prepared using the solid-phase extractant preparation method of the present invention offers the dual advantages of low raw material cost and low production cost. It can replace expensive octadecyl silica gel solid-phase extractants, effectively adsorbing hydrophobic o-phenyl ester compounds and reducing the cost of batch solid-phase extraction testing of o-phenyl esters. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a method for preparing a solid phase extractant according to an embodiment of the present invention;

[0021] Figure 2 is a scanning electron microscope image of a common tobacco stem according to an embodiment of the present invention;

[0022] Figure 3is a scanning electron micrograph of a solid phase extractant prepared from ordinary tobacco stems in one embodiment of the present invention; Figure 4 This is the extraction chromatographic separation diagram of dimethyl phthalate in lake water using the solid phase extractant prepared by the present invention. DETAILED DESCRIPTION

[0023] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0024] In the present invention, unless otherwise specified, directional terms such as "upper" and "lower" generally refer to directions in the assembled state. "Inside" and "outside" refer to inside and outside relative to the outline of each component itself.

[0025] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0026] like Figure 1 As shown, the present invention provides a method for preparing a solid-phase extractant, which is made of tobacco stems. The method for preparing the solid-phase extractant comprises the following steps: S1, grinding the tobacco stems to obtain coarse stem powder; S2, heating the coarse stem powder in a water bath to remove impurities, wherein the water bath heating treatment comprises the step of heating the coarse stem powder in a water bath using a strong alkaline solution; S3, transferring the coarse stem powder that has completed the water bath heating treatment to an extractor to remove oil impurities in the coarse stem powder and thereby obtain a crude extractant product; and S4, washing and drying the crude extractant product in sequence to obtain a solid-phase extractant.

[0027] Specifically, the tobacco stems are first ground to obtain coarse stem powder, which is conducive to the full contact between the solid phase extractant prepared later and the extracted solution. Furthermore, it is necessary to remove impurities such as protein, pigment and oil contained in the coarse stem powder to prevent these impurities from mixing into the extract during the extraction process and interfering with the extract. Among them, step S2 heats the coarse stem powder in a water bath, especially using a strong alkaline solution for water bath heating, which can effectively remove large molecular impurities such as protein and pigment in the coarse stem powder; step S3 puts the coarse stem powder after removing the large molecular impurities into the extractor to remove oil impurities, and in this process, it can further remove residual impurities that were not removed in step S2. After the impurities are removed, a crude extractant product is obtained, and the crude extractant product is washed with a liquid that will not interfere with the subsequent extraction process to further remove small molecular impurities in the crude extractant product, and the crude extractant product is dried to finally obtain a solid phase extractant.

[0028] The raw material used in the solid-phase extractant preparation method of the present invention is tobacco stems, discarded during tobacco leaf production. Tobacco stems are inexpensive and readily available. Furthermore, the overall preparation process is relatively simple, eliminating the need for silane coupling agents and catalysts used in the preparation of octadecyl silica gel, and eliminating the need for cumbersome processing steps such as end-capping. This significantly reduces the production cost of the solid-phase extractant. Furthermore, as a natural material, tobacco stems are renewable and environmentally friendly, facilitating resource reuse. Furthermore, the porous structure formed by the lignin and cellulose in the processed tobacco stems provides a high specific surface area, enhancing the adsorption of hydrophobic organic molecules (such as o-phenyl esters). Furthermore, the tobacco stems have multiple functional groups on their surface, such as hydroxyl and carboxyl groups, which can adsorb target compounds through mechanisms such as hydrogen bonding and electrostatic interactions. Therefore, the solid-phase extractant prepared using the solid-phase extractant preparation method of the present invention offers the dual advantages of low raw material cost and low production cost. It can replace expensive octadecyl silica gel solid-phase extractants, effectively adsorbing hydrophobic o-phenyl ester compounds and reducing the cost of batch solid-phase extraction testing of o-phenyl esters.

[0029] In some embodiments of the present invention, in step S1, in order to make the solid phase extractant have a higher specific surface area so that it can fully adsorb the extract, the particle size of the coarse stem powder is made between 50-200 meshes.

[0030] In some embodiments of the present invention, in step S2, the coarse stem powder is heated in a water bath while being wrapped in a filter; in step S3, the coarse stem powder is transferred to an extractor while being wrapped in a filter to remove oil impurities; wherein the filter comprises multiple layers of a first filter membrane and a second filter membrane alternately stacked; and the innermost layer of the filter in contact with the coarse stem powder is the first filter membrane, and the filter pores of the first filter membrane are smaller than the filter pores of the second filter membrane.

[0031] Specifically, the first filter membrane has a large pore size, resulting in a fast filtration rate and preventing larger molecules from clogging the pores, allowing the liquid to continuously pass through the first filter membrane and come into contact with the coarse stem powder. The second filter membrane has a smaller pore size and greater toughness, preventing damage to the second filter membrane and preventing the coarse stem powder from mixing into the liquid. Multiple layers of the first and second filter membranes are alternately stacked to form a filter, ensuring both a fast filtration rate and improved filtration quality.

[0032] In some embodiments of the present invention, in step S2, the water bath heating treatment further includes the following process: wrapping the coarse stem powder in a filter, and then heating it in a water bath for the first time with pure water; wherein the pure water is high-purity water that has been purified to remove more than 90% of ions and impurities; after completing the first water bath heating, heating it in a water bath for the second time with a strong alkaline solution.

[0033] Specifically, the crude stem powder is placed in pure water and heated in a water bath to remove impurities such as dust attached to the surface of the tobacco stems. In addition, the water is purified to remove more than 90% of ions and impurities, which can avoid the introduction of other impurities during the preparation of the solid phase extractant. Figure 2 and Figure 3 As shown, during the second waterbath heating treatment, the strong alkaline solution denatures proteins, removing them from the liquid. It also disrupts the structure of pigment molecules, removing them. It also loosens the stem cell wall structure, increasing porosity and specific surface area, and improving the extraction efficiency of the solid-phase extractant made from crude stem powder. Compared with acidic solutions, strong alkaline solutions can quickly break down disulfide and hydrogen bonds in proteins, completely denaturing them and facilitating their removal. Furthermore, strong alkaline solutions have a stronger destructive effect on various pigments and better protect the cellulose structure.

[0034] In some embodiments, water purification can be achieved by using a water purifier. For example, a Milli-Q water purifier produced by Merck Millipore can be used to purify water to obtain the desired pure water.

[0035] In some embodiments of the present invention, during the first water bath heating treatment, the solid-liquid mass volume ratio of the coarse stem powder to pure water is 1: (4~6), the heating temperature is 60-80°C, and the water bath heating time is 20-40 minutes; during the second water bath heating treatment, the solid-liquid mass volume ratio of the coarse stem powder to the strong alkaline solution is 1: (4~6), the heating temperature is 40-60°C, and the water bath heating time is 2-4 hours. Specifically, in order to save consumables, under the premise of ensuring the effect of the water bath heating treatment, in the first water bath heating, the solid-liquid mass volume ratio of the coarse stem powder to pure water should not be greater than 1:6. In the second water bath heating, the solid-liquid mass volume ratio of the coarse stem powder to the strong alkaline solution should not be greater than 1:6.

[0036] In some embodiments of the present invention, the solute of the strong alkaline solution may be at least one of NaOH and KOH, and the concentration of the strong alkaline solution is 0.5-2 mol / L.

[0037] Specifically, during the second water bath heating, the NaOH or KOH in the strong alkaline solution can effectively remove impurities such as proteins. Furthermore, while fully exerting the strong alkaline solution's effectiveness, the concentration of the strong alkaline solution is controlled between 0.5 and 2 mol / L to prevent excessive concentrations from destroying substances in the crude stem powder, such as cellulose, that are beneficial for solid-phase extraction.

[0038] In some embodiments of the present invention, a Soxhlet extractor is selected as the extractor, and the coarse stem powder wrapped by the filter is transferred to an extraction tube of the Soxhlet extractor, and the top opening of the extraction tube is connected to a condenser; pure water is added to an extraction bottle connected to the bottom of the Soxhlet extractor, and the extraction bottle is heated, the heating temperature is 100~110℃, and the heating reflux time is 3~8h.

[0039] Specifically, the water vapor formed by the vaporization of the liquid pure water in the extraction bottle under heating conditions enters the extraction tube and the condenser in turn, and condenses into droplets in the condenser and falls back into the extraction tube to soak the coarse stem powder and dissolve the grease impurities therein. When the liquid level in the extraction tube exceeds the top of the siphon tube, the siphon action is activated, and the liquid flows back to the extraction bottle through the siphon tube. The liquid in the extraction bottle is heated again to realize the cycle of distillation and condensation until the grease impurities in the coarse stem powder are fully dissolved. The Soxhlet extractor uses a cyclic extraction method to repeatedly distill and condense pure water to achieve efficient removal of grease impurities in the coarse stem powder.

[0040] In some embodiments of the present invention, in step S4, the step of washing the crude extractant product includes: first, taking out the crude extractant product and placing it in a first container filled with pure water, so that the crude extractant product is fully in contact with the pure water, and filtering the pure water mixed with the crude extractant product; transferring the crude extractant product obtained by filtration to a second container filled with methanol, repeatedly mixing it with methanol and filtering it.

[0041] Specifically, the crude extractant product is washed with pure water and methanol in sequence to further remove residual impurities in the crude extractant product. Since pure water and methanol are commonly used liquids in the solid phase extraction process, pure water and methanol will not interfere with the analysis of the extract.

[0042] In some embodiments of the present invention, in step S4, the step of drying the crude extractant product includes: vacuum drying the crude extractant product obtained by filtration to obtain a solid phase extractant.

[0043] On the other hand, the present invention provides an extraction and detection method for o-phenyl esters, which uses the solid phase extractant prepared in the above embodiment and includes the following steps: (1) activating the extraction column, filling the solid phase extractant into the empty extraction column to prepare an extraction column, and activating the extraction column; (2) taking a preset amount of a sample solution containing o-phenyl ester compounds and adding it to the activated extraction column; (3) after the sample solution has passed through the column, rinsing the extraction column with quantitative pure water, eluting the extraction column with quantitative acetonitrile, and collecting the eluate; (4) drying the eluate, and then adding the dried eluate to a quantitative organic solvent for re-dissolution to obtain a liquid to be tested on the machine, and then sending the liquid to be tested on the machine to be tested in a liquid chromatography-ultraviolet detector for detection to obtain a chromatogram of the liquid to be tested on the machine.

[0044] Particularly, after the sample solution joins in the extraction column, it is subjected to gravity and flows out downwards, and due to the hydrophobicity of solid phase extraction agent, moisture flows out from the lower end of extraction column, and the o-phenyl esters in the sample solution are retained in the solid phase extraction agent.Then use pure water dripping to adsorb the solid phase extraction agent of o-phenyl esters, to remove the compound impurities that are retained in the solid phase extraction agent.Finally use acetonitrile as eluent, utilize its adsorption effect to o-phenyl esters to be higher than the adsorption effect of solid phase extraction agent to o-phenyl esters, thereby make the o-phenyl esters that are attached to the solid phase extraction agent be dissolved in acetonitrile.After the eluate of the o-phenyl esters of oven dry is obtained, the eluate is dissolved in an organic solvent, sent into liquid chromatography-ultraviolet detector and detected and analyzed.

[0045] In some embodiments, the eluate can be dissolved in methanol for on-chip detection.

[0046] In some embodiments of the present invention, when activating the extraction column, a preset amount of solid phase extractant is loaded into the empty extraction column and compressed with a sieve plate to form an extraction column; then, a fixed amount of acetonitrile and a fixed amount of pure water are sequentially added to the extraction column to activate the extraction column.

[0047] The present invention is further described below by taking the solid phase extraction of dimethyl phthalate (a common substance in the class of o-phenyl esters) as an example.

[0048] Example 1

[0049] First, prepare the solid phase extraction agent as follows:

[0050] (1) Grind the tobacco stems using a grinder, wrap the resulting powder in a filter, and heat it in a water bath with pure water for the first time. The solid-liquid mass-to-volume ratio of the tobacco stem powder to pure water is 50 g:200 mL, and heat at 60°C for 20 minutes.

[0051] (2) The solvent was replaced with a 0.5 mol / L strong alkaline solution and heated in a water bath for the second time at 40°C for 2 h. Similarly, the solid-liquid mass volume ratio of the tobacco stem coarse powder to the strong alkaline solution was 50 g:200 mL.

[0052] (3) The tobacco stem powder was wrapped with a filter and placed in a Soxhlet extractor. Pure water (the solid-liquid mass volume ratio of tobacco stem powder to pure water was 50 g:500 mL) was added and heated under reflux at 100 °C for 3 h to obtain a crude extractant product.

[0053] (4) The crude extractant was taken out from the filter, washed with water and methanol (the solid-liquid mass volume ratio of the crude tobacco stem extractant to water and methanol was 50 g:200 mL), and vacuum dried to constant weight to obtain the solid phase extractant.

[0054] Next, a solid phase extraction agent is used to prepare an extraction column, and the steps are as follows:

[0055] Accurately weigh 150 mg of solid phase extraction agent into a 6 mL SPE extraction empty column with a sieve plate, continuously tap it to make it evenly filled, cover the upper end of the extraction empty column with the sieve plate and press it tightly to form an extraction column.

[0056] Finally, the prepared extraction column was used to detect dimethyl phthalate in lake water. The steps are as follows:

[0057] (1) Take 1 mL of a 1 mg / mL standard solution of dimethyl phthalate in a 100 mL volumetric flask, add lake water to make up to volume, and prepare a 10 µg / mL spiked solution, which will be used as the sample solution.

[0058] (2) Under the action of gravity, 3 mL of acetonitrile and pure water were used to activate the extraction column in turn; then 1 mL of the sample solution was added to the extraction column and allowed to slowly flow through the extraction column under the action of gravity. 1 mL of pure water was used as the eluent and allowed to flow through the extraction column under the action of gravity to remove the residual impurities adsorbed on the column; finally, 1 mL of acetonitrile was used as the eluent and allowed to flow through the extraction column under the action of gravity. The eluate was collected in a 1.5 mL centrifuge tube, heated and dried at 40 ° C using a nitrogen blower, and re-dissolved with 1 mL of methanol. 5 μL was taken and entered into the liquid chromatography-ultraviolet detector for analysis to prepare Table 1 and Figure 4 .

[0059] like Figure 4As shown, the sample effluent, eluent and eluent flowing through the extraction column were collected and sent to a liquid chromatography-ultraviolet detector, and chromatograms of the three were drawn. It can be seen that the sample effluent and the eluent basically do not contain dimethyl phthalate, while the chromatogram of the eluent has a clear peak shape of dimethyl phthalate, which further illustrates that dimethyl phthalate is enriched in the eluent, thereby proving that the solid phase extraction operation of dimethyl phthalate in the above embodiment is effective.

[0060] Example 2

[0061] First, prepare the solid phase extraction agent as follows:

[0062] (1) The tobacco stems were ground with a grinder, the coarse stem powder was wrapped with a filter, and pure water was added for the first water bath heating (the solid-liquid mass volume ratio of the tobacco stem coarse powder to pure water was 50 g:2500 mL), and heated at 80 °C for 40 minutes.

[0063] (2) Replace the solvent with a 2 mol / L strong base solution and heat it in a water bath at 60°C for 4 h.

[0064] (3) The crude stem powder was wrapped with a filter and placed in a Soxhlet extractor. Pure water (the solid-liquid mass volume ratio of crude stem powder to pure water was 50 g:1000 mL) was added and heated under reflux at 110 °C for 8 h to obtain a crude extractant product.

[0065] (4) The crude extractant was removed from the filter, washed with water and methanol (the solid-liquid mass volume ratio of the crude extractant to water and methanol was 50 g:500 mL), and vacuum dried to constant weight to obtain the solid phase extractant.

[0066] Next, a solid phase extraction agent is used to prepare an extraction column, and the steps are as follows:

[0067] Accurately weigh 150 mg of solid phase extraction agent into a 6 mL SPE extraction empty column with a sieve plate, continuously tap it to make it evenly filled, cover the upper end of the extraction empty column with the sieve plate and press it tightly to form an extraction column.

[0068] Finally, the prepared extraction column was used to detect dimethyl phthalate in lake water. The steps are as follows:

[0069] (1) Take 1 mL of a 1 mg / mL standard solution of dimethyl phthalate in a 100 mL volumetric flask, add lake water to make up to volume, and prepare a 10 µg / mL spiked solution, which will be used as the sample solution.

[0070] (2) Under the action of gravity, 3 mL of acetonitrile and pure water were used to activate the extraction column in sequence; then 1 mL of the sample solution was added to the extraction column and allowed to slowly flow through the extraction column under the action of gravity. 1 mL of pure water was used as the eluent and allowed to flow through the extraction column under the action of gravity to remove the residual impurities adsorbed on the column; finally, 1 mL of acetonitrile was used as the eluent and allowed to flow through the extraction column under the action of gravity. The eluate was collected in a 1.5 mL centrifuge tube, heated and dried at 40 °C using a nitrogen blower, and re-dissolved in 1 mL of methanol. 5 μL was taken and entered into the liquid chromatography-ultraviolet detector for analysis, and the result was obtained as Table 1.

[0071] Comparative Example 1

[0072] The sample solution in Example 1 was subjected to solid phase extraction using a commercially available HLB solid phase extraction column and then tested and analyzed to produce Table 1.

[0073] Comparative Example 2

[0074] The sample solution in Example 1 was subjected to solid phase extraction using a commercially available C18 solid phase extraction column and then tested and analyzed to produce Table 1.

[0075] Comparative Example 3

[0076] The sample solution in Example 1 was subjected to solid phase extraction using a commercially available SCX solid phase extraction column and then tested and analyzed to produce Table 1.

[0077]

[0078] Table 1

[0079] As shown in Table 1, in the solid-phase extraction treatment of dimethyl phthalate, the solid-phase extraction column filled with the solid-phase extraction agent prepared by the present invention has the advantages of fast column flow rate and high extraction recovery rate compared with three commercially available solid-phase extraction columns.

[0080] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0081] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0082] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for extracting and detecting o-phenyl esters, characterized in that: A solid phase extractant prepared by a solid phase extractant preparation method is used. The solid phase extractant is made of tobacco stems, and the preparation method of the solid phase extractant comprises the following steps: S1. Grinding tobacco stems to obtain coarse stem powder; S2. heating the coarse stem powder in a water bath to remove impurities, wherein the water bath heating treatment comprises heating the coarse stem powder in a water bath using a strong alkaline solution; S3, transferring the crude stem powder that has completed the water bath heating treatment to an extractor to remove oil impurities in the crude stem powder to obtain a crude extractant product; and S4, washing and drying the crude extractant in sequence to obtain the solid phase extractant; Wherein, in step S3, the extractor is a Soxhlet extractor, and the crude stem powder is transferred to an extraction tube of the Soxhlet extractor, wherein the top opening of the extraction tube is connected to a condenser; Add pure water to the extraction bottle connected to the bottom of the Soxhlet extractor, and heat the extraction bottle at a heating temperature of 100-110° C. and a heating reflux time of 3-8 hours; The extraction detection method of the o-phenyl esters comprises the following steps: activating an extraction column, filling the solid phase extractant into an empty extraction column to prepare an extraction column, and activating the extraction column; A preset amount of a sample solution containing an o-phenyl ester compound is added to the activated extraction column; after the sample solution has passed through the column, the extraction column is rinsed with a certain amount of pure water, and the extraction column is eluted with a certain amount of acetonitrile, and the eluate is collected; The eluate is dried, and then the dried eluate is added to a quantitative organic solvent for redissolution to obtain a liquid to be tested on the machine, and then the liquid to be tested on the machine is sent to a liquid chromatography-ultraviolet detector for detection to obtain a chromatogram of the liquid to be tested on the machine; The o-phenyl ester compound is dimethyl phthalate, The loading liquid includes lake water.

2. The extraction and detection method for o-phenyl esters according to claim 1, wherein When activating the extraction column, a preset amount of the solid phase extractant is filled into the empty extraction column and compressed with a sieve plate to prepare the extraction column; Then, a quantitative amount of acetonitrile and a quantitative amount of pure water are added to the extraction column in sequence to activate the extraction column.

3. The extraction and detection method of o-phenyl esters according to claim 1, wherein In the step S1, the particle size of the coarse stem powder is between 50-200 meshes.

4. The extraction and detection method for o-phenyl esters according to claim 1, wherein In the step S2, the coarse stem powder is subjected to the water bath heating treatment while being wrapped in a filter; in the step S3, the coarse stem powder is transferred to the extractor while being wrapped in the filter to remove oil impurities; The filter comprises multiple layers of alternately stacked first and second filter membranes; and the innermost layer of the filter in contact with the coarse stem powder is the first filter membrane, and the filter pores of the first filter membrane are smaller than the filter pores of the second filter membrane.

5. The extraction and detection method for o-phenyl esters according to claim 4, wherein In step S2, the water bath heating treatment further includes the following process: The coarse stem powder is wrapped in the filter and then heated in a water bath for the first time using pure water; wherein the pure water is high-purity water that has been purified to remove more than 90% of ions and impurities; After the first water bath heating is completed, the strong alkali solution is used to heat the mixture in a water bath for the second time.

6. The extraction and detection method for o-phenyl esters according to claim 5, wherein During the first water bath heating process, the solid-liquid mass volume ratio of the coarse stem powder to the pure water is 1:(4-6), the heating temperature is 60-80°C, and the water bath heating time is 20-40 minutes; During the second water bath heating treatment, the solid-liquid mass volume ratio of the coarse stem powder to the strong alkaline solution is 1:(4-6), the heating temperature is 40-60° C., and the water bath heating time is 2-4 hours.

7. The extraction and detection method for o-phenyl esters according to claim 6, wherein: The solute of the strong alkaline solution can be at least one of NaOH and KOH, and the concentration of the strong alkaline solution is 0.5-2 mol / L.

8. The extraction and detection method for o-phenyl esters according to claim 1, wherein In step S4, the step of washing the crude extractant product includes: First, the crude extractant product is taken out and placed in a first container containing pure water, so that the crude extractant product and the pure water are fully contacted, and the pure water mixed with the crude extractant product is filtered; the crude extractant product obtained by filtration is transferred to a second container containing methanol, and is repeatedly mixed with the methanol and filtered; And / or, in step S4, the step of drying the crude extractant product includes: vacuum drying the crude extractant product obtained by filtration to obtain the solid phase extractant.

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