A selective purification method for bisphenol compounds in solid sample extracts

Abstract

The present invention discloses a selective purification method for bisphenol compounds in solid sample extracts, belonging to the technical field of extraction and purification of organic pollutants. This method is applicable to the selective separation of bisphenol compounds such as BPAF, BPAP, BPZ, and TBBPA in solid sample extracts to achieve the purpose of efficient purification. Specifically, 13X molecular sieve is loaded into an empty solid-phase extraction tube, and the solid-phase extraction column is activated with an organic solvent to remove possible impurities. Then, the solid sample extract is loaded onto the solid-phase extraction column. Dichloromethane with a certain volume is used for elution to remove some interfering substances, and then a mixed solvent of methanol / dichloromethane with an appropriate ratio is used for elution to collect the target substances. The present invention can remove some lipid macromolecules and pigments in solid samples only through 13X molecular sieve solid-phase extraction. On the one hand, it ensures the purification recovery rate of bisphenol compounds, etc., and on the other hand, it saves time and labor costs and is more environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of extraction and purification of organic pollutants, and particularly relates to a selective purification method for bisphenol compounds such as BPAF, BPAP, BPZ, and TBBPA in the extraction solution of solid samples using 13X molecular sieve as a solid-phase extraction adsorbent. Background Art

[0002] Bisphenol compounds (BPs) are a class of chemical substances with two phenolic hydroxyl groups and similar structures. Due to their advantages such as chemical stability, excellent heat resistance and ductility, relatively simple production process, and low cost, they are commonly used in the production of many important chemical raw materials, such as high molecular polymers like polycarbonate and epoxy resin, and are usually applied to daily necessities such as water bottles, baby bottles, container coatings, and building materials. These non-natural new organic pollutants of BPs are prone to enrichment and difficult to degrade, and long-term low-level exposure will have an impact on human health, causing a series of diseases such as obesity, cancer, and cardiovascular diseases. At present, the production and use of bisphenol compounds are increasing globally. Due to the similar structure of bisphenol compounds to sex hormones, they show negative effects such as endocrine disruption, reproductive toxicity, and neurotoxicity on the human body, and belong to endocrine disrupting substances. At present, the Canadian government has identified and further risk-controlled 34 bisphenol compounds including BPAF, BPAP, and BPZ.

[0003] Solid samples are important gathering places for bisphenol compounds. For example, bisphenol compounds enter the soil through wastewater discharge. The content of bisphenol compounds in the soil is mostly at the concentration level of ng / g. Although gel permeation chromatography columns can effectively remove macromolecules such as pigments and lipids, they have problems such as complex operation, large consumption of organic solvents, and long time consumption.

[0004] 13X molecular sieve is a porous aluminosilicate material with a complete framework structure, belonging to zeolite molecular sieves with a low silicon-aluminum ratio. It has the characteristics of easy synthesis, large surface area, and good hydrophilicity, so it has good ion exchange and adsorption properties and has been widely used in drying and separation. The application of 13X molecular sieve is mainly based on the selective adsorption according to the size of the pores inside the crystal, and is commonly used for the drying and purification of industrial gases and the adsorption of heavy metal ions in the sewage discharged from industrial production. It is also commonly used for the desulfurization of liquid hydrocarbons and natural petroleum gas, but there is no report on the research of 13X molecular sieve in the purification of bisphenol compounds. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a selective purification method for bisphenol compounds in the extraction solution of solid samples using 13X molecular sieve as a solid-phase extraction adsorbent.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A selective purification method for bisphenol compounds in a solid sample extract mainly includes the following steps:

[0008] (1) Extraction and concentration: Extract and concentrate the bisphenol compounds in the solid sample, and replace them with dichloromethane or a solvent with similar properties to obtain an extract;

[0009] (2) Filling the solid-phase extraction column: Select a solid-phase extraction column and fill it with 13X molecular sieve;

[0010] (3) Activation: Use dichloromethane or a solution with similar properties to activate the filled solid-phase extraction column;

[0011] (4) Loading: Load the extract obtained in step (1) onto the solid-phase extraction column in step (3), and discard the effluent;

[0012] (5) Rinsing: Use dichloromethane or a solution with similar properties as the rinsing solution for rinsing to remove interfering substances, and discard the effluent;

[0013] (6) Elution: Use a methanol-dichloromethane mixed solution with a volume ratio of 1:5 to 1:1 as the eluent for elution to elute the bisphenol compounds, and collect the eluate in a glass centrifuge tube.

[0014] Further, the bisphenol compounds in step (1) include BPAF, BPAP, BPZ, TBBPA, and the log k ow value is greater than 3.9.

[0015] Further, the extraction methods in step (1) include Soxhlet extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and accelerated solvent extraction.

[0016] Further, the solid samples in step (1) include soil, sediment, food, and solid waste.

[0017] Further, the extraction solvent in step (1) is a single solvent or a mixed solvent of two or more of acetone, methanol, ethanol, ethyl acetate, etc.

[0018] Further, the concentration methods in step (1) include rotary evaporation and nitrogen purging.

[0019] Further, the specific process of step (2) is: Select a glass solid-phase extraction column, install a fiber sieve plate in the glass solid-phase extraction column, fill it with 13X molecular sieve, and then compact it with the fiber sieve plate.

[0020] Further, the amount of dichloromethane or a solution with similar properties in step (3) is more than 1 times the volume of the solid-phase extraction column.

[0021] Further, in step (4), the volume ratio of the extraction solution to the solid-phase extraction column is not higher than 6:1.

[0022] Further, in step (5), the ratio of the eluent to the dosage of 13X molecular sieve is not greater than 20 mL:200 mg.

[0023] Further, in step (6), the ratio of the elution solution to the dosage of 13X molecular sieve is not less than 10 mL:200 mg.

[0024] Further, the elution solution collected in step (6) is blown to dry by nitrogen, and after re-dissolution with dichloromethane or a solution with similar properties, it is subjected to analysis and detection.

[0025] The beneficial effects of the present invention compared with the prior art are as follows:

[0026] By using 13X molecular sieve as the solid-phase extraction adsorbent, the present invention can remove macromolecules such as lipids and pigments in the solid sample extraction solution, ensuring the accuracy of the determination of bisphenol compounds, saving time and labor costs, and being more environmentally friendly. Description of the Drawings

[0027] In order to more clearly illustrate the embodiments of the present invention, the drawings related to the embodiments will be briefly introduced below.

[0028] Figure 1 Effect of the elution solvent on the elution curve of bisphenol compounds on the 13X molecular sieve solid-phase extraction column, where a is the elution curve of BPAF / BPAP, and b is the elution curve of BPZ.

[0029] Figure 2 Color change of the soil extraction solution before and after purification by 13X molecular sieve.

[0030] Figure 3 Gel permeation chromatogram of the soil extraction solution before and after purification by 13X molecular sieve.

[0031] Figure 4 Liquid chromatography comparison chart of the soil extraction solution after purification by different adsorbents (13X molecular sieve, C 18 , HLB, PEP-2), (a) is the chromatogram of the spiked soil extraction solution after treatment with different fillers, where 1: spiked soil extraction solution, 2: 2 ppm mixed standard solution of BPAF / BPAP / BPZ, 3-6 are the chromatograms of the soil extraction solution treated with C 18 , 13X molecular sieve, PEP-2 and HLB respectively; (b) is the chromatogram of the blank acetonitrile solution, (c) is C 18Amplified chromatograms of spiked soil extracts after treatment, (d) is the amplified chromatogram of spiked soil extracts treated with 13X molecular sieve, (e) is the amplified chromatogram of spiked soil extracts treated with PEP-2, and (f) is the amplified chromatogram of spiked soil extracts treated with HLB.

[0032] Figure 5 It is a comparison chromatogram of liquid chromatography before and after purification of soil extracts added with bisphenol compound mixed samples by 13X molecular sieve. Among them, (a) is soil extract + spiked, (b) is 2 ppm BPAF / BPAP / BPZ mixed standard solution, and (c) is soil extract + spiked + 13X molecular sieve.

[0033] Figure 6 It is a comparison chromatogram of liquid chromatography before and after purification of soil extracts added with TBBPA standard by 13X molecular sieve. Among them, (a) is soil extract + spiked, (b) is 2 ppm TBBPA standard solution, (c) is soil extract + 13X molecular sieve + spiked, and (d) is soil extract + spiked + 13X molecular sieve. Detailed implementation mode

[0034] The present invention will be described in detail below in conjunction with embodiments. However, the implementation modes of the present invention are not limited thereto. Obviously, the embodiments described below are only partial embodiments of the present invention. For those skilled in the art, without creative labor, obtaining other similar embodiments will fall within the protection scope of the present invention.

[0035] Example 1:

[0036] (1) Weigh 6 portions of 200 mg of 13X molecular sieve in parallel, respectively load them into solid-phase extraction glass columns with a volume of 3 mL, and compact them with fiber sieve plates at both the upper and lower ends of the 13X molecular sieve;

[0037] (2) Activation: Use 3 mL of dichloromethane to activate the solid-phase extraction column respectively;

[0038] (3) Loading: Dissolve 6 portions of 1 μg bisphenol compound mixed standard samples in 2 mL of dichloromethane respectively and then load them; at the same time, wash the sample bottle with 0.5 mL of dichloromethane and combine the loaded samples; collect the loaded fractions in glass centrifuge tubes, and record them as F1-F6 respectively;

[0039] (4) Elution: 6 solid-phase extraction columns are eluted with methanol-dichloromethane mixed solvents (volume ratios are 1:1, 1:2, 1:3, 1:4, 1:5, 0:1) respectively, and the elution volume is 2 * 10 mL; collect each elution fraction in a glass centrifuge tube, and record them as F7-F18 in sequence;

[0040] (5) Concentration: Each fraction of F1 - F18 was purged with nitrogen until nearly dry, and then acetonitrile was added to make the volume up to 0.5 mL.

[0041] (6) Analysis: High - performance liquid chromatography was used for analysis and detection. A C 18 reverse - phase chromatographic column (250 mm×4.6 mm, 5 μm) was used for analysis and detection. The flow rate was 1 mL / min, the column temperature was 25 °C, and gradient elution was performed with mobile phase A (acetonitrile) and B (water) as follows: at 0 min, A:B = 50:50; at 20 min, A:B = 80:20; at 20.1 min, A:B = 100:0; at 28 min, A:B = 100:0; at 28.1 min, A:B = 50:50; at 35 min, A:B = 50:50.

[0042] It can be Figure 1 seen that 20 mL of dichloromethane could not elute the target compound, while 10 mL of methanol - dichloromethane with a volume ratio of 1:4 had an elution effect of over 80% on BPAF, BPAP, and BPZ.

[0043] Example 2:

[0044] (1) Weigh 200 mg of 13X molecular sieve in parallel in 2 portions, and separately load them into solid - phase extraction glass columns with a volume of 3 mL, and compact them with fiber sieve plates at both the upper and lower ends of the 13X molecular sieve.

[0045] (2) Activation: Use 3 mL of dichloromethane to activate the solid - phase extraction column separately.

[0046] (3) Loading: Weigh 20 mg of corn oil separately, dissolve it in 2 mL of dichloromethane and then load it; at the same time, wash the sample bottle with 0.5 mL of dichloromethane and combine the samples for loading; collect the loading fractions in glass centrifuge tubes and label them as F19 and F20 respectively.

[0047] (4) Rinsing: Use 1 mL and 5 mL of dichloromethane to rinse the solid - phase extraction column separately, and collect the rinsing fractions in glass centrifuge tubes, labeled as F21 and F22.

[0048] (5) Elution: Use 2×10 mL of methanol - dichloromethane mixed solvent with a volume ratio of 1:4 to elute the solid - phase extraction column separately, and collect the eluates F23 - F26.

[0049] (6) Concentration: Each fraction of F19 - F26 obtained was purged with nitrogen until nearly dry, weigh the glass centrifuge tube, and calculate the oil content as shown in Table 1.

[0050] Table 1 Elution effect of lipids (20 mg of corn oil) determined by the weighing method on 13X molecular sieve

[0051]

[0052] It can be concluded from Table 1 that when 1 mL to 5 mL of dichloromethane is used for elution, more than 90% of the grease can be removed. Combining with Example 1, it can be seen that using dichloromethane within 20 mL for elution can effectively remove lipid substances without affecting the elution of the target substance.

[0053] Example 3:

[0054] (1) Weigh 200 mg of molecular sieve and fill it into a 3 mL glass solid-phase extraction column. Use fiber sieve plates to compact both the upper and lower ends and compact the fiber sieve plates.

[0055] (2) Activation: Use 3 mL of dichloromethane to activate the solid-phase extraction column.

[0056] (3) Loading: Prepare two identical concentrated soil extracts #1 and #2, and load them into the solid-phase extraction column respectively. After washing the flask with 0.5 mL of dichloromethane, load it and discard the effluent.

[0057] (4) Elution: Use 5 mL of dichloromethane for elution and discard the eluate.

[0058] (5) Elution: Use 10 mL of 1:4 (v / v) methanol-dichloromethane for elution and collect the eluate.

[0059] (6) Nitrogen blowing and reconstitution: Blow dry the eluate with nitrogen and add 2 mL of dichloromethane for reconstitution.

[0060] (7) Pass the sample obtained in (6) through a 13X molecular sieve solid-phase extraction column again. The steps are the same as (1) to (5). Blow dry its eluate with nitrogen, add 2 mL of dichloromethane for reconstitution and then conduct instrumental analysis.

[0061] (8) Analysis: Use gel permeation chromatography (dichloromethane as the mobile phase, flow rate of 5 mL / min) for detection and analysis.

[0062] From Figure 2 it can be seen that before and after the soil extract is purified by the molecular sieve, the color becomes lighter and the pigment impurities are effectively removed; from Figure 3 it can be seen that after two passes through the 13X molecular sieve solid-phase extraction column, the removal efficiency of lipid substances in the soil extract can reach more than 80%.

[0063] Example 4:

[0064] Compare the purification effects of 13X molecular sieve and three commercial adsorbents (HLB, C 18 , PEP-2) as solid-phase extraction adsorbents on the soil extract.

[0065] (1) Filling the solid-phase extraction column: Weigh 200 mg of 13X molecular sieve, 200 mg of C 18 , 100 mg of HLB and 100 mg of PEP-2 adsorbent and fill them into a 3 mL glass solid-phase extraction column, and compact both the upper and lower ends with fiber sieve plates;

[0066] (2) Activation: Activate the 13X molecular sieve solid-phase extraction column with 3 mL of dichloromethane, activate the C 18 solid-phase extraction column with 2 mL of methanol and 2 mL of water, activate the HLB solid-phase extraction column with 3 mL of methanol and 3 mL of water, and activate the PEP-2 solid-phase extraction column with 3 mL of methanol and 3 mL of water;

[0067] (3) Loading: After concentrating the soil extract, add the corresponding solvent and add it to the corresponding solid-phase extraction column; Use 2 mL of dichloromethane for loading on the 13X molecular sieve solid-phase extraction column, use 2 mL of 5% methanol solution for loading on the PEP-2 solid-phase extraction column, and use 2 mL of 10% methanol solution for loading on the C 18 and HLB solid-phase extraction columns; Wash the flask with 0.5 mL of the corresponding organic solvent and then combine for loading, and discard the effluent;

[0068] (4) Elution: Elute the 13X molecular sieve solid-phase extraction column with 5 mL of dichloromethane, elute the C 18 solid-phase extraction column with 2 mL of 10% methanol, elute the HLB solid-phase extraction column with 2 mL of 0.1N HCl and 5 mL of 10% methanol, and elute the PEP-2 solid-phase extraction column with 1 mL of ultrapure water and 2 mL of 5% methanol; Discard the eluate; Except for the 13X molecular sieve solid-phase extraction column, other solid-phase extraction columns are dried with a mechanical pump for 20 - 30 min;

[0069] (5) Elution: Elute the 13X molecular sieve solid-phase extraction column with 10 mL of a methanol-dichloromethane mixed solution with a volume ratio of 1:4, elute the C 18 solid-phase extraction column with 5 mL of 15% methanol-ethyl acetate solution, and elute the HLB and PEP-2 solid-phase extraction columns with 5 mL of methanol; Collect the eluates separately;

[0070] (6) Nitrogen blowing and volume fixation: Blow dry the eluate with nitrogen, add 2 μg of the bisphenol compound mixed standard solution, and fix the volume to 1 mL with acetonitrile.

[0071] (7) Analysis: Perform detection and analysis using liquid chromatography, and the results are shown in Figure 4.

[0072] As can be seen from Figure 4 , the 13X molecular sieve, C 18 , HLB and PEP-2 solid-phase extraction columns all have good purification effects on the soil extract, and the purification effect of the 13X molecular sieve is better than that of C 18, HLB and PEP-2 adsorbents.

[0073] Example 5:

[0074] Efficiency of selectively purifying soil extract using 13X molecular sieve

[0075] (1) Pack the solid-phase extraction column: Weigh 200 mg of 13X molecular sieve and pack it into a 3 mL glass solid-phase extraction column, and compact it with fiber sieve plates at both the upper and lower ends;

[0076] (2) Activation: Use 3 mL of dichloromethane to activate the 13X molecular sieve solid-phase extraction column;

[0077] (3) Loading: Prepare two identical concentrated soil extracts #1 and #2. Add 2 μg of bisphenol compound mixed standard solution to the concentrated solution of #1 extract. After adding it to the solid-phase extraction column, wash the flask with 0.5 mL of dichloromethane and then combine and load the sample, discarding the effluent; directly add the concentrated solution of #2 extract to the solid-phase extraction column, wash the flask with 0.5 mL of dichloromethane and then combine and load the sample, discarding the effluent;

[0078] (4) Elution: Use 5 mL of dichloromethane to elute the 13X molecular sieve solid-phase extraction column, discarding the eluate;

[0079] (5) Elution: Use 10 mL of 1:4 (v / v) methanol-dichloromethane to elute the 13X molecular sieve solid-phase extraction column, and collect the eluate;

[0080] (6) Nitrogen blowing and volume fixation: Blow the two eluates to dry with nitrogen respectively. Add 1 mL of acetonitrile to #1 for volume fixation, and add 2 μg of bisphenol compound mixed standard solution to #2, and fix the volume to 1 mL with acetonitrile.

[0081] (7) Analysis: Use liquid chromatography for detection and analysis.

[0082] It can be seen from Figure 5 and Figure 6 that the efficiency of selectively purifying soil extract using 13X molecular sieve can reach more than 90%, and it has no obvious effect on the content of bisphenol compounds.

[0083] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A selective purification method for bisphenol compounds in a solid sample extract, characterized in that: It includes the following steps: (1) Extract, concentrate the bisphenol compounds in the solid sample, and displace them with dichloromethane to obtain an extraction solution; (2) Select a solid-phase extraction column and pack it with 13X molecular sieve; (3) Activate the solid-phase extraction column with dichloromethane; (4) Load the extraction solution obtained in step (1) onto the solid-phase extraction column in step (3), and discard the effluent; (5) Use dichloromethane as the eluent for elution, and discard the effluent; (6) Use a methanol-dichloromethane mixed solution with a volume ratio of 1:5 to 1:1 as the eluent for elution, collect the eluate; The solid sample in step (1) includes soil and sediment.

2. The selective purification method according to claim 1, characterized in that: The extraction methods in step (1) include Soxhlet extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and accelerated solvent extraction; the extraction solvents are single solvents or mixed solvents of two or more of acetone, methanol, ethanol, and ethyl acetate.

3. The selective purification method according to claim 1, characterized in that: The concentration methods in step (1) include rotary evaporation and nitrogen purging.

4. The selective purification method according to claim 1, wherein: The specific process of step (2) is: select a glass solid-phase extraction column, install a fiber sieve plate into the glass solid-phase extraction column, pack it with 13X molecular sieve, and then compact it with the fiber sieve plate.

5. The selective purification method according to claim 1, characterized in that: In step (3), the amount of dichloromethane used is more than 1 times the volume of the solid-phase extraction column.

6. The selective purification method according to claim 1, wherein: In step (4), the volume ratio of the extraction solution to the solid-phase extraction column is not higher than 6:

1.

7. The selective purification method according to claim 1, characterized in that: In step (5), the ratio of the eluent to the amount of 13X molecular sieve used is not greater than 20 mL:200 mg.

8. The selective purification method according to claim 1, characterized in that: In step (6), the ratio of the eluent to the amount of 13X molecular sieve used is not less than 10 mL:200 mg.

9. The selective purification method according to claim 1, characterized in that: The eluate collected in step (6) is blown to dryness with nitrogen, redissolved with dichloromethane, and then analyzed and detected.

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