Method for detecting polycyclic aromatic hydrocarbon in matcha
A solid-phase extraction method using magnetic MOFs and MIPs composite materials has solved the problems of low extraction efficiency and poor selectivity of polycyclic aromatic hydrocarbons (PAHs) in food samples, achieving efficient and highly selective PAH detection, which is suitable for matcha samples.
Patent Information
- Application Number
- CN202511364915.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-23
- Publication Date
- 2025-11-14
AI Technical Summary
Existing technologies have low extraction efficiency and poor selectivity for polycyclic aromatic hydrocarbons in food samples, and traditional SPE materials such as silica gel and C18 fillers perform poorly in complex samples.
A composite material of magnetic metal-organic frameworks (MOFs) and molecularly imprinted polymers (MIPs) was used for solid-phase extraction of polycyclic aromatic hydrocarbons in matcha samples. This composite material combines the high surface area of MOFs with the good selectivity of MIPs to improve extraction efficiency and selectivity.
The method achieved a high extraction rate of 85%-95% for polycyclic aromatic hydrocarbons in matcha samples, with an interference recovery rate of less than 5% and a detection limit of 0.1 ng/mL to 1 ng/mL. The material is reusable and the recovery rate remains above 90%.
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Figure CN120948663A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid phase extraction (SPE) technology, specifically to a solid phase extraction method based on magnetic metal-organic framework (MOF) and molecularly imprinted polymer (MIP) composite materials, for the efficient extraction and detection of polycyclic aromatic hydrocarbons (PAHs) in food samples. Background Technology
[0002] Polycyclic aromatic hydrocarbons (PAHs) are a common class of environmental pollutants with carcinogenic and mutagenic effects. They primarily threaten human health through air pollution, industrial emissions, and accumulation in the food chain. Therefore, rapid and accurate detection of PAHs is crucial for environmental protection and food safety. Existing methods for PAH detection include gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC), but these methods typically require complex sample pretreatment and are relatively inefficient.
[0003] Solid-phase extraction (SPE) is a common sample pretreatment technique widely used due to its simplicity and high separation efficiency. However, traditional SPE materials such as silica gel and C18 packing often exhibit poor selectivity and low recovery rates when extracting polycyclic aromatic hydrocarbons (PAHs) from complex samples. In recent years, magnetic MOFs and MIPs have become research hotspots due to their high surface area, good selectivity, and efficient adsorption capacity, but their application in food samples remains relatively limited.
[0004] Therefore, this invention proposes a solid-phase extraction method based on magnetic MOFs and MIPs composite materials, which can efficiently extract polycyclic aromatic hydrocarbons from matcha samples, overcome the shortcomings of existing technologies, and improve extraction efficiency and selectivity. Summary of the Invention
[0005] This invention provides a SPE method based on magnetic MOFs and MIPs composite materials, specifically designed for the efficient extraction and detection of PAHs in matcha samples. This method combines the unique advantages of magnetic MOFs and MIPs, significantly improving the extraction efficiency and selectivity of PAHs, thus solving the problems of low extraction efficiency and poor selectivity of PAHs in existing technologies.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for detecting polycyclic aromatic hydrocarbons in matcha, the steps of which are as follows:
[0008] S1. After synthesizing the magnetic metal-organic framework material, a composite material is formed by adjusting the mass ratio of metal-organic framework to molecularly imprinted polymer to a range of 1:1 to 1:3.
[0009] S2. Add the composite material to the matcha sample and perform solid-phase extraction to extract polycyclic aromatic hydrocarbons from the sample and wash it.
[0010] S3. Quantitative detection of extracted polycyclic aromatic hydrocarbons is performed using gas chromatography-mass spectrometry or high performance liquid chromatography.
[0011] Optionally, in the method for detecting polycyclic aromatic hydrocarbons in matcha, the specific surface area of the magnetic metal-organic framework material is 300-1000 m². 2 / g, with a porosity of 40-70%.
[0012] Optionally, in the method for detecting polycyclic aromatic hydrocarbons (PAHs) in matcha, the recovery rate of PAHs in the matcha sample is 85%-95% and the recovery rate of other interfering substances in the matcha sample is 1%-5% during the solid-phase extraction step using a magnetic metal-organic framework and molecularly imprinted polymer composite material.
[0013] Optionally, in the method for detecting polycyclic aromatic hydrocarbons in matcha, the washing step in the solid-phase extraction process uses an ethanol-water mixture with a volume ratio of 1:1 to 2:1, and performs three washes, each lasting 10-20 minutes.
[0014] Optionally, the method for detecting polycyclic aromatic hydrocarbons in matcha uses gas chromatography-mass spectrometry for quantitative detection of polycyclic aromatic hydrocarbons, with a detection limit of 0.01 ng / mL to 0.05 ng / mL and a deviation of 1% to 5%.
[0015] Optionally, the method for detecting polycyclic aromatic hydrocarbons (PAHs) in matcha includes one or more of acenaphthene, benzo(a)pyrene, dibenzo(a,h)anthracene, pyrene, fluoranthracene, benzo(b)fluoranthracene, benzo(k)fluoranthracene, and dibenzo(a)anthracene. The magnetic metal-organic framework and molecularly imprinted polymer composite material can efficiently extract these PAH molecules with a sensitivity of 0.1 ng / mL to 1 ng / mL.
[0016] Optionally, in the method for detecting polycyclic aromatic hydrocarbons in matcha, the amount of magnetic metal-organic framework and molecularly imprinted polymer composite material used is 1-5 times the weight of the matcha sample.
[0017] Optionally, in the method for detecting polycyclic aromatic hydrocarbons in matcha, the magnetic metal-organic framework and molecularly imprinted polymer composite material can operate stably under pH conditions of 3-9.
[0018] The beneficial effects of this invention are:
[0019] The composite material prepared in this invention can efficiently extract PAHs from matcha samples, with an extraction rate as high as 85%-95%, exhibiting strong selectivity and a recovery rate of less than 5% for interfering substances. This composite material possesses good sensitivity, with a detection limit of 0.1 ng / mL to 1 ng / mL. Its magnetic properties make the solid-phase extraction process convenient, efficient, and reusable, maintaining a recovery rate above 90%. Overall, it demonstrates excellent performance, providing an environmentally friendly, economical, and efficient method for the detection of polycyclic aromatic hydrocarbons, with broad application prospects. Attached Figure Description
[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.
[0021] Figure 1 This is a line graph showing the extraction efficiency of different samples of the present invention at different PAH concentrations;
[0022] Figure 2 This is a bar chart showing the recovery rates of PAHs and interfering substances in different matcha samples of the present invention. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0024] Example 1:
[0025] The preparation method of magnetic MOF materials is as follows:
[0026] S1. Dissolve ferric nitrate and terephthalic acid in deionized water at a mass ratio of 1:1 to prepare a solution;
[0027] S2. Add ethanol as a solvent, stir at 300 rpm and heat to 80°C, react for 4 hours;
[0028] S3. Remove insoluble matter by magnetic separation to obtain magnetic MOF materials;
[0029] S4. Clean the magnetic MOFs three times with deionized water and ethanol, and then vacuum dry them at 60°C for 12 hours to obtain the dried magnetic MOFs material.
[0030] The preparation method of MIPs is as follows:
[0031] S1. Dissolve the target molecule benzo(a)pyrene in methanol at a concentration of 0.1 mol / L;
[0032] S2. Add acrylic acid (AA) as a monomer and divinylbenzene (EDMA) as a crosslinking agent to the solution at concentrations of 0.3 mol / L and 0.2 mol / L, respectively.
[0033] S3. Add azobisisobutyronitrile (AIBN) as an initiator to promote polymerization, at a concentration of 0.02 mol / L;
[0034] S4. React the reaction system in a 60℃ water bath for 4 hours to obtain MIPs;
[0035] S5. Wash three times with deionized water and methanol in a volume ratio of 1:1 to remove unreacted monomers and crosslinking agents, and then vacuum dry at 60°C for 12 hours to obtain MIPs.
[0036] The preparation method of the magnetic MOFs / MIPs composite material is as follows:
[0037] S1. Mix magnetic MOFs and MIPs at a mass ratio of 1:1;
[0038] S2. Add an appropriate amount of ethanol to the mixture, the volume of which is twice the total mass, and sonicate for 20 minutes to ensure uniform mixing.
[0039] S3. Stir at 60℃ and 300rpm for 4 hours to form a composite material;
[0040] S4. Remove unreacted material by magnetic separation, and wash three times with ethanol and deionized water in a 1:1 volume ratio to remove residues;
[0041] S5. Vacuum drying at 60℃ for 12h yields a composite material of magnetic MOFs and MIPs.
[0042] The method for detecting polycyclic aromatic hydrocarbons in matcha in Example 1 is as follows:
[0043] S1. Mix 25g of magnetic MOFs and MIPs composite material with 5g of matcha sample, then add 50mL of ethanol-water mixture with a volume ratio of 1:1, stir at 300rpm for 10min, and let stand for 30min to allow the composite material to fully combine with PAHs in the matcha sample.
[0044] S2. Add 50 mL of ethanol-water mixture with a volume ratio of 1:1, shake for 10 min to remove dissolved impurities, then use magnetic separation method to separate the composite material from the solution, collect the solution, and wash three times under the same conditions.
[0045] S3. Use 50 mL of ethanol as the elution solution, shake for 10 min, and remove the composite material by magnetic separation to elute and extract PAHs from the composite material;
[0046] S4. Collect the extract and perform gas chromatography-mass spectrometry (GC-MS) analysis to quantitatively detect the extracted PAHs.
[0047] Example 2:
[0048] To investigate the effect of different ratios of MOFs and MIPs on the extraction efficiency of polycyclic aromatic hydrocarbons, when the mass ratio of the magnetic MOFs to MIPs composite material was 2:1:
[0049] The preparation methods for magnetic MOFs and MIPs materials are the same as in Example 1;
[0050] The preparation method of the magnetic MOFs / MIPs composite material is as follows:
[0051] S1. Mix magnetic MOFs and MIPs at a mass ratio of 2:1;
[0052] S2. Add an appropriate amount of ethanol to the mixture, the volume of which is twice the total mass, and sonicate for 20 minutes to ensure uniform mixing.
[0053] S3. Stir at 60℃ and 300rpm for 4 hours to form a composite material;
[0054] S4. Remove unreacted material by magnetic separation, and wash three times with ethanol and deionized water in a 1:1 volume ratio to remove residues;
[0055] S5. Vacuum drying at 60℃ for 12h yields a composite material of magnetic MOFs and MIPs.
[0056] The detection method for polycyclic aromatic hydrocarbons in matcha in Example 2 is the same as that in Example 1.
[0057] Example 3:
[0058] To investigate the effect of different ratios of MOFs and MIPs on the extraction efficiency of polycyclic aromatic hydrocarbons, when the mass ratio of the magnetic MOFs to MIPs composite material was 3:1:
[0059] The preparation methods for magnetic MOFs and MIPs materials are the same as in Example 1;
[0060] The preparation method of the magnetic MOFs / MIPs composite material is as follows:
[0061] S1. Mix magnetic MOFs and MIPs at a mass ratio of 3:1;
[0062] S2. Add an appropriate amount of ethanol to the mixture, the volume of which is twice the total mass, and sonicate for 20 minutes to ensure uniform mixing.
[0063] S3. Stir at 60℃ and 300rpm for 4 hours to form a composite material;
[0064] S4. Remove unreacted material by magnetic separation, and wash three times with ethanol and deionized water in a 1:1 volume ratio to remove residues;
[0065] S5. Vacuum drying at 60℃ for 12h yields a composite material of magnetic MOFs and MIPs.
[0066] The detection method for polycyclic aromatic hydrocarbons in matcha in Example 3 is the same as that in Example 1.
[0067] Comparative Example 1:
[0068] To investigate the effect of the lack of magnetic MOFs on extraction efficiency:
[0069] The preparation method of the MIPs material is the same as that in Example 1. The specific steps of the detection method of polycyclic aromatic hydrocarbons in matcha in Comparative Example 1 are as follows:
[0070] The specific steps of the detection method for polycyclic aromatic hydrocarbons in matcha in Comparative Example 1 are as follows:
[0071] S1. Mix 25g of MIPs material with 5g of matcha sample, then add 50mL of ethanol-water mixture with a volume ratio of 1:1, stir at 300rpm for 10min, and let stand for 30min to allow the MIPs to fully bind with the PAHs in the matcha sample.
[0072] S2. Add 50 mL of ethanol-water mixture with a volume ratio of 1:1, shake for 10 min to remove dissolved impurities, then separate the MIPs from the solution by filtration, collect the solution, and wash three times under the same conditions.
[0073] S3. Use 50 mL of ethanol as the elution solution, shake for 10 min, and remove MIPs by magnetic separation. Elute and extract PAHs from MIPs.
[0074] S4. Collect the extract and perform gas chromatography-mass spectrometry (GC-MS) analysis to quantitatively detect the extracted PAHs.
[0075] Comparative Example 2:
[0076] To investigate the effect of the lack of MIPs on extraction efficiency:
[0077] The preparation method of the magnetic MOF material is the same as that in Example 1. The specific steps of the detection method of polycyclic aromatic hydrocarbons in matcha in Comparative Example 1 are as follows:
[0078] The specific steps of the detection method for polycyclic aromatic hydrocarbons in matcha in Comparative Example 2 are as follows:
[0079] S1. Mix 25g of magnetic MOFs material with 5g of matcha sample, then add 50mL of ethanol-water mixture with a volume ratio of 1:1, stir at 300rpm for 10min, and let stand for 30min to allow the magnetic MOFs material to fully combine with PAHs in the matcha sample.
[0080] S2. Add 50 mL of ethanol-water mixture with a volume ratio of 1:1, shake for 10 min to remove dissolved impurities, and then use magnetic separation method to separate the magnetic MOFs material from the solution. Collect the solution and wash it three times under the same conditions.
[0081] S3. Use 50 mL of ethanol as the elution solution, shake for 10 min, and remove the magnetic MOFs material by magnetic separation. Extract PAHs from the magnetic MOFs material by elution.
[0082] S4. Collect the extract and perform gas chromatography-mass spectrometry (GC-MS) analysis to quantitatively detect the extracted PAHs.
[0083] Performance testing
[0084] 1. Extraction efficiency test
[0085] First, standard PAH solutions of known concentrations were prepared at 0.1 ng / mL, 1 ng / mL, 5 ng / mL, 10 ng / mL, and 50 ng / mL to cover different concentration ranges. 5 g of PAH sample was mixed with 25 g of magnetic MOFs and MIPs composite material, and 50 mL of a 1:1 ethanol-water mixture was added, ensuring full contact between the composite material and the PAH sample. The mixture was stirred at 300 rpm for 10 minutes, then allowed to stand for 30 minutes to allow the composite material to fully bind with the PAHs in the matcha sample. Next, the composite material was removed by magnetic separation, and the eluent was collected. Subsequently, the sample was washed three times with 50 mL of a 1:1 ethanol-water mixture, 15 minutes each time, to remove soluble impurities. Using 50 mL of ethanol as the eluent, the mixture was shaken for 10 minutes, and the composite material was removed by magnetic separation, eluting the extracted PAHs from the composite material. Finally, the extract was collected and quantitatively analyzed by GC-MS to calculate the extraction rate.
[0086] Table 1 Extraction efficiency data of different samples at different PAHs concentrations
[0087]
[0088] The extraction efficiency of the MOFs and MIPs composite material remained high at different concentrations, especially at low concentrations, with Example 1 showing the best extraction performance. In contrast, the extraction efficiency was lower when MIPs or MOFs were used alone, especially at low concentrations. The synergistic effect of the composite material significantly improved the extraction capacity, demonstrating its advantages in the extraction of polycyclic aromatic hydrocarbons.
[0089] 2. Selective Testing
[0090] 5g of matcha sample was mixed with 25g of MOFs and MIPs composite material to ensure sufficient contact between the composite material and PAHs and potentially interfering organic substances such as sugars and proteins in the matcha sample. 50mL of a 1:1 ethanol-water mixture was added, and the mixture was stirred at 300rpm for 10 minutes, then allowed to stand for 30 minutes to allow the composite material to fully adsorb PAHs. Next, the composite material was removed by magnetic separation, and the solution was collected. The sample was washed three times with 50mL of a 1:1 ethanol-water mixture, 15 minutes each time, to remove soluble impurities. Using 50mL of ethanol as the eluent, the mixture was shaken for 10 minutes, and the composite material was removed by magnetic separation, eluting the extracted PAHs from the composite material. Finally, the extract was collected and analyzed by GC-MS to determine the PAH concentration and calculate the selective recovery rate of PAHs. Compared with the recovery rates of other interfering substances such as sugars and proteins, the recovery rate of PAHs should be higher than 85%, while the recovery rate of other interfering substances should be lower than 5%.
[0091] Table 2. Recovery rates of PAHs and interfering substances in different matcha samples.
[0092]
[0093] The composite material of MOFs and MIPs exhibits significant advantages in PAH extraction, particularly in PAH recovery, which consistently exceeds 85%, while the recovery rate of other interfering substances is less than 5%. In contrast, when MIPs or MOFs are used alone, the PAH recovery rate is significantly lower, but the extraction rates of interfering substances such as carbohydrates and proteins are higher, indicating that the composite material can improve the accuracy and efficiency of PAH extraction.
[0094] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for detecting polycyclic aromatic hydrocarbons in matcha, characterized in that, The method includes the following steps: S1. After synthesizing the magnetic metal-organic framework material, a composite material is formed by adjusting the mass ratio of metal-organic framework to molecularly imprinted polymer to a range of 1:1 to 1:
3. S2. Add the composite material to the matcha sample and perform solid-phase extraction to extract polycyclic aromatic hydrocarbons from the sample and wash it. S3. Quantitative detection of extracted polycyclic aromatic hydrocarbons is performed using gas chromatography-mass spectrometry or high performance liquid chromatography.
2. The method for detecting polycyclic aromatic hydrocarbons in matcha according to claim 1, characterized in that, The specific surface area of the magnetic metal-organic framework material is 300-1000 m². 2 / g, with a porosity of 40-70%.
3. The method for detecting polycyclic aromatic hydrocarbons in matcha according to claim 1, characterized in that, In the solid-phase extraction step, the magnetic metal-organic framework and molecularly imprinted polymer composite material achieved a recovery rate of 85%-95% for polycyclic aromatic hydrocarbons in matcha samples and a recovery rate of 1%-5% for other interfering substances in matcha samples.
4. The method for detecting polycyclic aromatic hydrocarbons in matcha according to claim 1, characterized in that, The washing step in the solid-phase extraction process uses an ethanol-water mixture with a volume ratio of 1:1 to 2:1, and performs three washes, each lasting 10-20 minutes.
5. The method for detecting polycyclic aromatic hydrocarbons in matcha according to claim 1, characterized in that, The quantitative detection of the polycyclic aromatic hydrocarbons was performed using gas chromatography-mass spectrometry, with a detection limit of 0.01 ng / mL to 0.05 ng / mL and a deviation of 1% to 5%.
6. The method for detecting polycyclic aromatic hydrocarbons in matcha according to claim 1, characterized in that, The polycyclic aromatic hydrocarbons are one or more of acenaphthene, benzo(a)pyrene, dibenzo(a,h)anthracene, pyrene, fluoranthracene, benzo(b)fluoranthracene, benzo(k)fluoranthracene, and dibenzo(a)anthracene, and the magnetic metal-organic framework and molecularly imprinted polymer composite material can efficiently extract these polycyclic aromatic hydrocarbon molecules with a sensitivity of 0.1 ng / mL-1 ng / mL.
7. The method for detecting polycyclic aromatic hydrocarbons in matcha according to claim 1, characterized in that, The amount of the magnetic metal-organic framework and molecularly imprinted polymer composite material used is 1-5 times the weight of the matcha sample.
8. The method for detecting polycyclic aromatic hydrocarbons in matcha according to claim 1, characterized in that, The magnetic metal-organic framework and molecularly imprinted polymer composite material can operate stably under pH conditions of 3-9.