CN-121978237-A - Detection method and application of PE (polyethylene) microplastic in lipid-containing organic matrix

Abstract

The invention belongs to the technical field of detection, and particularly relates to a detection method and application of PE (polyethylene) microplastic in a lipid-containing organic matrix. The method comprises the steps of (1) mixing a PE standard substance and a solvent to prepare a standard working solution, sequentially cleaning and extracting a sample to be detected, extracting PE in the sample to be detected to obtain a sample solution to be detected, and (2) carrying out thermal cracking-gas chromatography-mass spectrometry combined detection analysis after evaporating the solvent from the standard solution and the solution to be detected in the step (1) to finish detection of PE microplastic in a lipid-containing organic matrix. The detection method provided by the invention can be used for detecting PE microplastic in the lipid-containing organic matrix, and can be used for realizing accurate qualitative and quantitative analysis of PE microplastic in the lipid-containing organic matrix by using a thermal cracking-gas chromatography-mass spectrometry detection method, and the method is stable and good in repeatability.

Inventors

• ZHANG HONGMEI
• TIAN MENG
• GE JIALI
• LI WENXING
• QIN BING

Assignees

• 上海微谱检测科技集团股份有限公司

Dates

Publication Date

20260505

Application Date

20260204

Claims (10)

1. 1. A method for detecting PE microplastic in a lipid-containing organic matrix, which is characterized by comprising the following steps: (1) Sequentially cleaning and extracting a sample to be detected, extracting PE in the sample to be detected, and obtaining a sample solution to be detected; (2) Taking the standard solution and the solution to be detected in the step (1) to evaporate the solvent, and then carrying out thermal cracking-gas chromatography-mass spectrometry combined detection analysis to finish detection of PE microplastic in the lipid-containing organic matrix; The thermal cracking-gas chromatography-mass spectrometry combined detection adopts a single-click mode, and the cracking temperature is 400-550 ℃.
2. 2. The method according to claim 1, wherein the washing is performed with an organic solvent, wherein the organic solvent comprises one or more of aliphatic hydrocarbon of C 5 -C 8 , halogenated hydrocarbon of C 1 -C 2 , alcohol solvent of C 2 -C 4 ; Preferably, the organic solvent includes at least one of n-hexane, n-heptane, cyclohexane, petroleum ether, ethanol, acetonitrile, dichloromethane, chloroform, carbon tetrachloride, diethyl ether, methyl tert-butyl ether, tetrahydrofuran, ethyl acetate, acetone, methanol or isopropanol.
3. 3. The method according to claim 2, wherein the washing comprises a first washing and a second washing, the first washing and the second washing forming a washing cycle, and repeating the washing cycle until the sample to be measured is free of oil stains.
4. 4. The method of claim 3, wherein the first washing and the second washing are each independently selected from at least one of the following conditions: (1) The cleaning temperature is 40-70 ℃; (2) The cleaning time is 5-15 min; (3) The organic solvent is n-hexane; (4) The organic solvent is ethanol.
5. 5. The method according to claim 1, wherein the extraction is performed using an extractant comprising at least one of toluene, ethanol, o-xylene, m-xylene, p-xylene, acetone, acetonitrile, and methanol.
6. 6. The detection method according to claim 5, wherein the ratio of the sample to be detected and the extractant is 1g (10-40) mL.
7. 7. The method according to claim 1, wherein the thermal cracking-gas chromatography-mass spectrometry combined detection gas chromatography satisfies at least one of the following conditions: (1) The chromatographic column comprises an SH-I-5Sil MS chromatographic column, wherein the column length of the chromatographic column is 15-60 m, the inner diameter of the chromatographic column is 0.25mm, and the film thickness of the chromatographic column is 0.1-1 mu m; (2) The gas chromatography adopts a split-flow sample injection mode, and the split ratio is (3-6): 1; (3) The flow rate of the chromatographic column is 0.5-2 mL/min (4) The temperature of the sample inlet is 300-350 ℃; (5) The carrier gas was helium gas at a linear velocity of 36.1cm/sec.
8. 8. The method according to claim 1, wherein the thermal cracking-gas chromatography-mass spectrometry combined detection thermal cracking satisfies at least one of the following conditions: (1) The carrier gas is helium; (2) The temperature of the cracker-gas chromatography interface is 280-320 ℃; (3) The cracking time is 10-15 s.
9. 9. The method of claim 1, wherein mass spectrometry in the thermal cracking-gas chromatography-mass spectrometry combination detection satisfies at least one of the following conditions: (1) A full scan acquisition mode; (2) The scanning time is 10-30 min; (3) The ionization energy is 50-80 ev; (4) The scanning range is m/z 29-600; (5) The ion source is EI, positive ion mode; (6) The temperature of the ion source is 200-250 ℃; (7) The temperature of the gas chromatography-mass spectrometry interface is 300-330 ℃.
10. 10. Use of the detection method according to any one of claims 1-9 for detecting the content of PE microplastic in lipid-containing organic matrices.

Description

Detection method and application of PE (polyethylene) microplastic in lipid-containing organic matrix Technical Field The invention belongs to the technical field of detection, and particularly relates to a detection method and application of PE (polyethylene) microplastic in a lipid-containing organic matrix. Background Microplastic, an emerging global contaminant, is widely found in water, soil and organisms, and is increasingly being focused on the potential risks of the ecosystem and human health. Accurate detection of microplastic in environmental and biological samples is a prerequisite for assessing its contamination level and ecotoxicological effects. At present, the detection technology for microplastic mainly comprises a morphological observation-based spectrometry (such as fourier transform infrared spectrum and raman spectrum), wherein the fourier transform infrared spectrum and the raman spectrum can provide fingerprint information of a polymer and observe the morphology, but when a sample matrix is complex, the particle size is extremely small or the surface of the sample matrix is coated with organic matters, signals of the sample matrix are severely interfered, so that the recognition rate is reduced or even the sample matrix fails. Some related arts disclose the use of thermal cracking-gas chromatography-mass spectrometry techniques to detect microplastic in soil or water. However, when thermal cracking-gas chromatography-mass spectrometry combined techniques are applied to the detection of microplastic in complex biological matrices containing fat, serious matrix interference challenges are faced. The sample is rich in organic components such as lipid, protein and the like, and the thermal cracking behavior of the sample can seriously cover or interfere with the characteristic signals of the target microplastic. Therefore, development of a new method capable of effectively overcoming the interference of complex biological matrixes, particularly lipids, and realizing accurate quantitative and qualitative detection of PE (polyethylene) microplastic is urgently needed. Disclosure of Invention In order to solve the substrate interference challenges faced in the detection of PE microplastic in a lipid-containing organic substrate in the prior art, a first aspect of the present invention provides a method for detecting PE microplastic in a lipid-containing organic substrate, comprising the steps of: (1) Sequentially cleaning and extracting a sample to be detected, extracting PE in the sample to be detected, and obtaining a sample solution to be detected; (2) Taking the standard solution and the solution to be detected in the step (1) to evaporate the solvent, and then carrying out thermal cracking-gas chromatography-mass spectrometry combined detection analysis to finish detection of PE microplastic in the lipid-containing organic matrix; further alternatively, thermal cracking is detected by thermal cracking-gas chromatography-mass spectrometry in a single click mode, and the cracking temperature is 400-550 ℃. As examples, the cracking temperature may be 400 ℃, 420 ℃, 440 ℃, 460 ℃, 480 ℃, 500 ℃, 510 ℃, 530 ℃, 550 ℃, etc., but may also be any point value in the above range, without further limitation. The inventors have intensively studied and found that, for the detection of PE microplastic in lipid-containing organic matrix, the conventional thermal cracking-gas chromatography-mass spectrometry combined detection method can cause a decrease in detection accuracy due to component interference in the lipid, in particular, since the initial thermal decomposition temperature (about 400 ℃) of PE and the complete decomposition temperature (about 500 ℃) of fat in the organic matrix are significantly overlapped, an intermediate temperature point cannot be found to completely pyrolyze the lipid without any decomposition of PE when the conventional "double click mode" is adopted. If the temperature of the first step is set too low, the lipid removal is incomplete, serious background interference is generated, and if the temperature of the first step is increased to improve the lipid removal efficiency, the advanced cleavage loss of part of PE is necessarily caused, and the detection result is seriously low and distorted. According to the method provided by the invention, a single-click mode is adopted by thermal cracking, the cracking temperature is controlled to be 400-550 ℃, and the sample to be detected is accurately cleaned by the organic solvent before detection and analysis, so that the accurate qualitative and quantitative analysis of PE (polyethylene) microplastic in the lipid-containing organic matrix can be realized, and the method is stable and high in accuracy. The lipid-containing organic matrix refers to a sample to be tested containing fat, and includes, as examples, biological tissues (e.g., fish, mussel, liver, and human pathological tissues), blood, food residues containing oils, and b