Method for detecting and analyzing halogenated organic matters in landfill leachate and polluted water body thereof

Abstract

The invention discloses a method for detecting and analyzing halogenated organic matters in landfill leachate and polluted water thereof, which comprises the following steps: acidifying a sample by using formic acid through a combined solid-phase extraction method of HLB solid-phase extraction and PPL solid-phase extraction, respectively performing solid-phase extraction and enrichment on the water sample by using an HLB solid-phase extraction column and a PPL solid-phase extraction column, and eluting by using methanol, the method comprises the following steps of: performing solid-phase extraction and enrichment on a water sample, respectively performing FT-ICR MS detection on the solid-phase extraction and enrichment samples, respectively performing molecular formula matching, molecular screening, molecular information summarization and sample data statistical analysis on two types of FT-ICR MS detection data, taking a union set of the two types of FT-ICR MS detection data to obtain all soluble halogenated organic matters (HOCs) in the water sample, and then visualizing the types of the halogenated organic matters through a mulberry-based diagram. According to the method, the molecular information of HOCs in the sample, especially the soluble halogenated organic matter containing Cl and Br molecules, can be more sufficiently obtained, and the occurrence characteristics, molecular characteristics and distribution characteristics of halogenated soluble organic matter molecules in the sample in a water body can be more clearly and comprehensively displayed.

Description

Technical Field

[0001] The invention relates to the field of environmental protection, and in particular to a method for detecting and analyzing halogenated organic matter in garbage leachate and its polluted water body. Background Art

[0002] Halogenated organic compounds (HOCs), also known as halogenated organic pollutants, include fluorinated organics, chlorinated organics, brominated organics, etc. HOCs pose a serious threat to the environment and human health due to their persistence and ability to accumulate in organisms. Most HOCs are endocrine disruptors, which can cause neurotoxicity, immunotoxicity, and reproductive damage to organisms. Abandoned domestic waste contains a variety of HOCs, which will be enriched from solid waste into leachate due to rainfall, the water content of the waste itself, and biodegradation. Once the impermeable layer of the landfill is damaged, HOCs will migrate into the groundwater with the leachate, posing a serious threat to the environment and surrounding organisms.

[0003] Mass spectrometry has become an effective method for detecting HOCs in the environment. For example, high performance liquid chromatography coupled with electrospray ionization-mass spectrometry has been used to identify polar HOCs, and gas chromatography-mass spectrometry has been used to detect low-mass and volatile HOCs. However, these methods can only detect some HOCs in the environment, and there are still a large number of unknown HOCs that have not been detected. Therefore, non-targeted ultra-high resolution mass spectrometry technology has been applied to HOCs detection in recent years. For example, previous researchers used Orbitrap mass spectrometry to detect HOCs in high-salinity organic wastewater (CN 118183937 A), but the resolution of Orbitrap mass spectrometry is usually between 100,000 and 1 million, while the resolution of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is usually above one million. Therefore, the resolution of FT-ICRMS is better than that of Orbitrap mass spectrometry. In addition to resolution, the accuracy of FT-ICR MS in the low mass range is also better than that of Orbitrap mass spectrometry. Therefore, FT-ICR MS is an effective method for high-precision characterization of HOCs in environmental samples.

[0004] When using FT-ICR MS to characterize HOCs in the environment, during the solid phase extraction stage of sample pretreatment, a solid phase extraction column with a filler such as C18 or HLB is usually used to enrich the HOCs in the sample. However, solid phase extraction can only extract part of the HOCs in the water sample (DOC enrichment rate is about 50%). Therefore, the halogenated soluble organic matter molecules finally obtained are only a part of the original sample, which makes it difficult to fully clarify the occurrence, migration and transformation of HOCs in the environment. Summary of the invention

[0005] In order to solve the above problems, the inventors conducted intensive research and found that a combined solid phase extraction method of HLB solid phase extraction and PPL solid phase extraction was used, in which HLB solid phase extraction columns and PPL solid phase extraction columns were used to perform solid phase extraction enrichment on water samples, and then Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) detection was performed respectively. The two FT-ICR MS detection data were respectively subjected to molecular formula matching of organic molecules, molecular screening, molecular information aggregation and sample data statistical analysis, and the two were combined to obtain all soluble halogenated organic matter in the water sample, which can more comprehensively collect, detect and analyze the halogenated organic compounds in the water sample, thereby completing the present invention.

[0006] The object of the present invention is to provide a detection and analysis method for halogenated organic matter in landfill leachate and its contaminated water bodies. The method adopts a combined solid phase extraction method of HLB solid phase extraction and PPL solid phase extraction, respectively adopts HLB solid phase extraction column and PPL solid phase extraction column to carry out solid phase extraction enrichment on water samples, then respectively carries out FT-ICRMS detection on the solid phase extraction enriched samples, respectively carries out molecular formula matching of organic molecules, molecular screening, molecular information aggregation and sample data statistical analysis on the two FT-ICR MS detection data, and takes the union of the two to obtain all soluble halogenated organic matter in the water sample.

[0007] In a preferred embodiment, fresh leachate collected from a domestic waste landfill and groundwater samples upstream and downstream of the landfill to be tested and analyzed are sent to a laboratory for testing and analysis within one week of collection for storage and pretreatment.

[0008] In a further preferred embodiment, the collected water samples are filtered, preferably through a 0.45 μm filter membrane, to fully remove insoluble organic matter such as suspended solids, and then the concentration of soluble organic carbon is measured, and the volume required for solid phase extraction is determined based on the DOC concentration.

[0009] In the present invention, as a method for measuring DOC concentration, commonly used methods in the art can be used, such as heating oxidation, ultraviolet irradiation-persulfate oxidation and OH free radical oxidation, etc., and can be carried out using a typical DOC measuring instrument in the art, without particular limitation.

[0010] The inventors have found that for HLB solid phase extraction and PPL solid phase extraction, when the DOC adsorbed on the solid phase extraction column is eluted and enriched to 1 mL and the DOC value is between 90-110 mg / L, the FT-ICR MS detection effect is excellent in this case.

[0011] Therefore, in a preferred embodiment, in order to ensure the comprehensiveness and integrity of the test and analysis results, the DOC of the original water sample of the landfill leachate, as well as the upstream and downstream groundwater samples, is measured after passing through the filter membrane. The lowest DOC in the water sample is used as the standard, and the other water samples are diluted until the DOC is equal to the lowest DOC. The inventors have found that the volume of the water sample required for solid phase extraction is preferably determined based on the enrichment rate of DOC of the solid phase extraction column between 30% and 50%.

[0012] After the above pretreatment, the water sample is then subjected to solid phase extraction.

[0013] In a preferred embodiment, for each water sample after membrane filtration, two water samples are taken according to the above-calculated volume, the pH of the sample is adjusted to a predetermined value with a formic acid solution, and an HLB solid phase extraction column and a PPL solid phase extraction column are respectively installed on a solid phase extraction device. For each solid phase extraction column, methanol and formic acid solution are used to elute and activate the column in turn, and then a certain amount of water sample is slowly added to the HLB solid phase extraction column and the PPL solid phase extraction column, respectively, so that the water sample is at a certain flow rate, such as 5 mL min -1 The halogenated organic compounds were enriched through a solid phase extraction column. After the water sample flowed through, formic acid was added to the HLB solid phase extraction column and the PPL solid phase extraction column to elute the column to remove the salt. The column was dried by nitrogen blowing and then eluted with methanol. The eluents were collected and nitrogen blowing was performed until the methanol was completely evaporated to obtain HLB solid phase extraction column enriched samples and PPL solid phase extraction column enriched samples for subsequent FT-ICR MS detection.

[0014] In a more preferred embodiment, for each water sample after membrane filtration, two water samples are taken according to the above-calculated volume, and the sample pH is adjusted to 2.0 with a 98% formic acid solution. The HLB solid phase extraction column and the PPL solid phase extraction column are respectively installed on the solid phase extraction device. For each solid phase extraction column, 12 mL of methanol and 12 mL of 0.01 mol / L formic acid solution are used for elution activation in turn, and then the water samples are slowly added to the HLB solid phase extraction column and the PPL solid phase extraction column, respectively, so that the water samples are stirred at a rate of 5 mL min. -1 The water sample was passed through the solid phase extraction column at a flow rate to enrich the halogenated organic compounds. After the water sample flowed through, 18 mL of 0.01 mol / L formic acid was added to the HLB solid phase extraction column and the PPL solid phase extraction column to elute the column to remove the salt. The column was dried by nitrogen blowing, and then eluted with 12 mL of methanol. The eluents were collected and blown with nitrogen until the methanol was completely volatilized to obtain the HLB solid phase extraction column enriched sample and the PPL solid phase extraction column enriched sample, respectively.

[0015] In the present invention, as the HLB solid phase extraction column, the lipophilic divinylbenzene and the hydrophilic N-vinyl pyrrolidone copolymer are used as fillers, and a commonly used HLB solid phase extraction column can be used, such as HLB solid phase extraction column.

[0016] In the present invention, as the PPL solid phase extraction column, the modified styrene-divinylbenzene polymer is used as the filler, and a commonly used PPL solid phase extraction column such as Bond Elut PPL solid phase extraction column can be used.

[0017] Before FT-ICR MS detection, the HLB solid phase extraction column enriched samples and the PPL solid phase extraction column enriched samples were dissolved in methanol, and the dissolved samples were detected by Bruker SolariX FT-ICR MS.

[0018] For the FT-ICR MS detection data of HLB solid phase extraction column enriched samples and PPL solid phase extraction column enriched samples, molecular formula matching, molecular screening, molecular information summary and Sankey diagram were performed to visualize the data of halogenated dissolved organic matter in the samples to clearly display the types of halogenated dissolved organic matter.

[0019] In a preferred embodiment of the present invention, the molecular formula of organic molecules is matched on two FT-ICR MS detection data through the ultra-high resolution mass spectrometry matching platform FTMSAnalysis of dissolved organic matter developed based on Gaussian distribution alignment algorithm, and then molecular screening, molecular information aggregation and visual analysis are performed through Sankey diagram.

[0020] The ultra-high-resolution mass spectrometry matching platform FTMSAnalysis platform for dissolved organic matter used in the present invention (see: Fu QL, Fujii M, Ma R. Development of a Gaussian-Based Alignment Algorithm for the Ultrahigh-Resolution Mass Spectra of Dissolved Organic Matter [J]. Analytical Chemistry, 2023, 95 (5): 2796-2803.) can efficiently and accurately match organic halogenated compounds.

[0021] When using the FTMSAnalysis platform to perform molecular formula matching, molecular screening, molecular information aggregation and sample data statistical analysis on the original data from FT-ICR MS detection, the union of the molecules matched by the HLB column and PPL column of the same sample is the total halogenated dissolved organic matter in the sample. Halogenated dissolved organic matter molecules with the same molecular formula are calculated only once, and then the types, distribution and characteristics of halogenated dissolved organic matter in the sample are analyzed using the Sankey diagram.

[0022] The present invention has the following advantages:

[0023] (1) By using a combined solid phase extraction method of HLB solid phase extraction and PPL solid phase extraction to simultaneously extract a sample, and using non-targeted ultra-high resolution FT-ICR MS technology to detect HOCs in environmental samples, it is possible to obtain more complete molecular information of HOCs in the sample, especially soluble halogenated organic matter containing Cl and Br molecules;

[0024] (2) By using formic acid instead of conventional HCl to acidify the sample before solid phase extraction, it is possible to effectively avoid the reaction of conventional HCl with certain components in the sample to generate new chlorine-containing organic matter when acidifying the sample. In addition, by using formic acid to acidify the sample, large molecular weight humus in the sample can be screened out during the solid phase extraction stage, thereby efficiently enriching small and medium molecular weight organic matter. HOCs are small and medium molecular weight, which can avoid large molecular weight humus interfering with the subsequent FT-ICR MS detection of HOCs.

[0025] (3) By using the Sankey diagram to analyze the molecular information of HOCs in the sample, the occurrence characteristics, molecular properties and distribution characteristics of the halogenated dissolved organic matter molecules in the sample can be more clearly and comprehensively displayed, which is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The sankey diagram showing the molecular information and properties of halogenated organic matter in the groundwater sample in Example 1;

[0027] Figure 2 The effect diagram of the solid phase extraction stage in Example 1 on the removal of large molecular weight humus and the enrichment of small and medium molecular weight organic matter in the groundwater sample is shown;

[0028] Figure 3 The sankey diagram showing the molecular information and properties of halogenated organic matter in the landfill leachate raw liquid sample in Example 2;

[0029] Figure 4 The effect diagram of the solid phase extraction stage in Example 2 on the removal of large molecular weight humus and the enrichment of small and medium molecular weight organic matter in the landfill leachate raw liquid sample is shown; DETAILED DESCRIPTION

[0030] The present invention is further described in detail below through the accompanying drawings and preferred embodiments. Through these descriptions, the characteristics and advantages of the present invention will become more clear and distinct.

[0031] Example 1

[0032] Groundwater samples contaminated by leachate were collected from a domestic waste landfill, stored at 4°C, and transported to the laboratory within one week. The groundwater samples were filtered through a 0.45 μm aqueous filter membrane, and the soluble organic carbon (DOC) of the samples was measured to be 24.86 mg / L.

[0033] Calculated based on the retention rate of the solid phase extraction column at 30-50%, it was concluded that when the sample volume passing through the column was 18-22 mL, the DOC value could be between 90-110 mg / L when the DOC adsorbed by the solid phase extraction column was eluted and enriched to 1 mL.

[0034] Take two water samples with a volume of 20 mL each, and adjust the pH of the two samples to 2.0 with a 98% formic acid solution; install the HLB solid phase extraction column and the PPL solid phase extraction column on the solid phase extraction device respectively, and wash and activate the HLB solid phase extraction column with 12 mL of methanol and 12 mL of 0.01 mol / L formic acid solution in turn, and wash and activate the PPL solid phase extraction column with 12 mL of methanol and 12 mL of 0.01 mol / L formic acid solution in turn, and then slowly add 1 portion of the water sample after adjusting the pH to the HLB solid phase extraction column and the PPL solid phase extraction column respectively, so that the water sample is heated at 5 mL min -1 The flow rate of the solid phase extraction column was 200 ℃ and the flow rate of the water sample was 200 ℃ and 300 ℃ respectively. After the water sample flowed through, 18 mL of 0.01 mol / L formic acid was added to the HLB solid phase extraction column and the PPL solid phase extraction column to elute the column respectively. The column was dried by nitrogen blowing and then eluted with 12 mL of methanol respectively. The eluents were collected respectively and the eluents were blown with nitrogen until the methanol was completely evaporated to obtain the HLB solid phase extraction column enriched sample and the PPL solid phase extraction column enriched sample respectively. They were dissolved with 1 mL of methanol respectively and then detected by FT-ICR MS respectively. Then, the molecular formula was matched using the FTMSAnalysis platform.

[0035] FT-ICR MS detection was performed using a Bruker SolariX FT-ICR MS, with an electrospray ionization source (ESI) in negative ion mode. The detection parameters were: continuous injection, injection speed of 120 μL / h, capillary inlet voltage of 4.0 kV, ion accumulation time of 0.06 s, collection mass range of 100-1600 Da, sampling points of 4M 32-bit data, and time domain signal superposition of 300 times to improve the signal-to-noise ratio.

[0036] The molecular formulas of halogenated organic matter finally matched by HLB and PPL solid phase extraction columns in leachate-contaminated groundwater are shown in Tables 1 and 2.

[0037] Table 1 Halogenated organic molecules obtained by HLB solid phase extraction column in groundwater contaminated by leachate

[0038]

[0039]

[0040] Table 2 Halogenated organic molecules obtained from PPL solid phase extraction column in groundwater contaminated by leachate

[0041]

[0042]

[0043] The results show that the HLB solid phase extraction column can enrich more chlorinated soluble organic matter. It detects more C10H10O8Cl2 and C12H17O9Cl3 than the PPL column, while the PPL solid phase extraction column can enrich more bromine-containing halogenated organic matter. The molecular formulas obtained by the two are combined, and the results are shown in Table 3.

[0044] Table 3 All halogenated organic molecules in groundwater contaminated by leachate

[0045]

[0046]

[0047] In order to more clearly and comprehensively represent the molecular information and properties of halogenated organic matter in groundwater contaminated by leachate, the molecular information in Table 3 was used as the basic data and the Sankey diagram drawing function in the Origin software was used to represent the molecular information and properties of halogenated organic matter in groundwater contaminated by leachate. Figure 1 The Sankey diagram shows the molecular information and properties of halogenated organic matter in the sample.

[0048] To further verify the effectiveness of our detection method, we used fluorescence spectroscopy to characterize the original solution of groundwater contaminated by leachate, the solid phase extraction column eluate (DOM adsorbed by the column, that is, DOM that can be detected by FT-ICR MS later), and the solid phase extraction column flow-through (DOM not adsorbed by the column, that is, DOM that was not extracted and could not be detected by FT-ICR MS). The three-dimensional fluorescence spectra are shown in Figure 2. Figure 2As shown in the figure, the three-dimensional fluorescence spectrum is a matrix spectrum characterized by the three-dimensional coordinates of excitation wavelength (y-axis)-emission wavelength (x-axis)-fluorescence intensity (z-axis). Dissolved fluorescent organic matter of different properties is located in different positions, and the fluorescence intensity represents the concentration of dissolved fluorescent organic matter. The fluorescence area integration method divides the three-dimensional fluorescence spectrum into different areas, each area represents a part of dissolved organic matter, including tyrosine and tyrosine-like substances (area I), tryptophan and tryptophan-like substances (area II), fulvic acid and fulvic acid-like substances (area III), soluble microbial products (area IV) and humic acid (area V). In general, the larger the excitation wavelength and emission wavelength of the dissolved organic matter, the larger its molecular weight. Therefore, the soluble microbial products and humic acid represented by areas IV and V have larger molecular weights, while the DOM represented by areas I, II and III are small and medium molecular weight DOM.

[0049] Figure 2 It shows that the two columns have good adsorption effects on small and medium molecular weight DOM in groundwater contaminated by leachate. Therefore, the method of formic acid acidification, PPL and HLB combined solid phase extraction and methanol elution can effectively enrich small and medium molecular weight DOM in groundwater contaminated by leachate, and can effectively screen out large molecular weight DOM (soluble microbial products, humic acid) in the sample. HOCs are usually small molecular compounds with molecular weights usually ranging from tens to hundreds of Daltons. They belong to small molecular weight DOM. Therefore, the method of this patent can be directed and efficiently enriched to HOCs in groundwater contaminated by leachate, and can effectively screen out large molecular weight soluble microbial products and humic acid in the sample to avoid their interference with HOCs testing in the subsequent mass spectrometry testing stage.

[0050] Example 2

[0051] The original leachate solution was collected from the domestic waste landfill in Example 1, stored at 4°C and transported to the laboratory within one week. The leachate sample was filtered through a 0.45 μm filter membrane, and then the sample DOC was measured, which was 875 mg / L. It is known that the DOC of groundwater contaminated by the leachate is 24.86 mg / L (see Example 1), so deionized water was used to dilute the original leachate solution to a DOC of 24.86 mg / L. During dilution, 10 mL of the original leachate solution was taken and placed in a 500 mL beaker, and then 342 mL of deionized water was added to dilute the original leachate solution, and the diluted solution was stored for later use.

[0052] Calculated based on the retention rate of the solid phase extraction column at 30-50%, it was concluded that when the sample volume passing through the column was 18-22 mL, the DOC value could be between 90-110 mg / L when the DOC adsorbed by the solid phase extraction column was eluted and enriched to 1 mL.

[0053] Take 2 diluted water samples with a volume of 20 mL each, and adjust the pH of the two samples to 2.0 with a 98% formic acid solution; install the HLB solid phase extraction column and the PPL solid phase extraction column on the solid phase extraction device respectively, and rinse and activate the HLB solid phase extraction column with 12 mL of methanol and 12 mL of 0.01 mol / L formic acid solution in turn, and rinse and activate the PPL solid phase extraction column with 12 mL of methanol and 12 mL of 0.01 mol / L formic acid solution in turn, and then slowly add 1 portion of the water sample after adjusting the pH to the HLB solid phase extraction column and the PPL solid phase extraction column respectively, so that the water sample is heated at 5 mL min -1 The flow rate of the solid phase extraction column was 200 ℃ and the flow rate of the solid phase extraction column was 200 ℃. After the water sample flowed through, 18 mL of 0.01 mol / L formic acid was added to the HLB solid phase extraction column and the PPL solid phase extraction column to elute the column respectively. The column was dried by nitrogen blowing and then eluted with 12 mL of methanol respectively. The eluents were collected and blew with nitrogen until the methanol was completely evaporated to obtain the HLB solid phase extraction column enriched sample and the PPL solid phase extraction column enriched sample respectively. They were dissolved with 1 mL of methanol respectively and then subjected to FT-ICR MS detection respectively, and the molecular formula was matched using the FTMSAnalysis platform.

[0054] The molecular formulas of halogenated organic matter finally matched by HLB and PPL solid phase extraction columns in the original leachate sample are shown in Tables 4 and 5.

[0055] Table 4 Halogenated organic molecules finally obtained from HLB solid phase extraction column in the original leachate solution

[0056]

[0057]

[0058] Table 5 Halogenated organic molecules finally obtained from PPL solid phase extraction column in the original leachate solution

[0059]

[0060]

[0061] It can be seen from Tables 4 and 5 that the halogenated dissolved organic matter finally obtained by the HLB and PPL columns has obvious differences in chlorine-soluble organic matter and brominated dissolved organic matter. The molecular formulas obtained by the two are taken as the union, and the results are shown in Table 6.

[0062] Table 6 All halogenated organic molecules in the leachate

[0063]

[0064]

[0065]

[0066] In order to more clearly and comprehensively represent the molecular information and properties of halogenated organic matter in leachate, the molecular information in Table 6 is used as the basic data, and the Sankey diagram drawing function in the Origin software is used to represent the molecular information and properties of halogenated organic matter in groundwater contaminated by leachate. Finally, the following can be obtained: Figure 3 The Sankey diagram showing the molecular information and properties of halogenated organic matter in the leachate.

[0067] To further verify the effectiveness of our detection method, we used fluorescence spectroscopy to characterize the original solution of the leachate (diluted 50 times), the solid phase extraction column eluate (DOM adsorbed by the column, that is, the DOM that can be detected by FT-ICR MS later), and the solid phase extraction column flow-through (DOM not adsorbed by the column, that is, DOM that was not extracted and could not be detected by FT-ICR MS). Figure 4 As shown, the two columns also have good adsorption effects on the small and medium molecular weight DOM represented by zones I, II and III in the leachate, and can effectively screen out the large molecular weight DOM (soluble microbial products, humic acid) in the sample. Therefore, the method of this patent can be directed and efficiently enriched into HOCs in the leachate, and can effectively screen out the large molecular weight soluble microbial products and humic acid in the leachate to avoid their interference with the HOCs test in the subsequent mass spectrometry test stage.

[0068] The present invention has been described in detail above in conjunction with preferred embodiments and exemplary examples. However, it should be noted that these specific embodiments and examples are only illustrative explanations of the present invention and do not constitute any limitation on the protection scope of the present invention. Without exceeding the spirit and protection scope of the present invention, various improvements, equivalent substitutions or modifications may be made to the technical content of the present invention and its implementation methods, all of which fall within the protection scope of the present invention. The protection scope of the present invention shall be subject to the attached claims.

Claims

1. A method for detecting and analyzing halogenated organic matter in landfill leachate and its contaminated water bodies. The method uses a combined solid phase extraction method of HLB solid phase extraction and PPL solid phase extraction, respectively using HLB solid phase extraction columns and PPL solid phase extraction columns to perform solid phase extraction enrichment on water samples, and then performing FT-ICR MS detection on the solid phase extraction enriched samples, respectively, performing molecular formula matching, molecular screening, molecular information aggregation and sample data statistical analysis on the two types of FT-ICRMS detection data of organic molecules, respectively, and taking the union of the two to obtain all soluble halogenated organic matter in the water sample.

2. The detection and analysis method according to claim 1, wherein: Fresh leachate collected from landfills and groundwater samples upstream and downstream of the landfills to be tested and analyzed shall be sent to the laboratory for testing and analysis within one week of collection for preservation and pretreatment.

3. The detection and analysis method according to claim 1, wherein: For the collected water samples, pass them through a filter membrane, preferably a 0.45 μm aqueous filter membrane, to fully remove insoluble organic matter such as suspended matter, and then measure the concentration of soluble organic carbon. The volume required for solid phase extraction is determined based on the concentration of soluble organic carbon (DOC).

4. The detection and analysis method according to claim 3, wherein: When the DOC adsorbed by the solid phase extraction column was eluted and enriched to 1 mL, the DOC value was between 90-110 mg / L, and FT-ICR MS detection was performed in this case.

5. The detection and analysis method according to claim 3, wherein: For the original water samples of landfill leachate, as well as the upstream and downstream groundwater samples, their DOCs are measured respectively after passing through the filter membrane. The lowest DOC in the water sample is used as the standard, and other water samples are diluted until the DOC is equal to the lowest DOC.

6. The detection and analysis method according to claim 1, wherein: The volume of water sample required for solid phase extraction was determined based on the enrichment rate of DOC by the solid phase extraction column being between 30% and 50%.

7. The detection and analysis method according to claim 6, wherein: For each water sample after membrane filtration, take 2 water samples respectively, adjust the sample pH to a predetermined value with formic acid solution, install HLB solid phase extraction column and PPL solid phase extraction column respectively on the solid phase extraction device, for each solid phase extraction column, wash and activate the column with methanol and formic acid solution in turn, then slowly add 1 water sample to the HLB solid phase extraction column and PPL solid phase extraction column respectively, so that the water sample passes through the solid phase extraction column at a certain flow rate to enrich the halogenated organic compounds, after the water sample flows out, add formic acid to the HLB solid phase extraction column and PPL solid phase extraction column to wash the column to remove the salt, dry the column with nitrogen, and then elute with methanol respectively, collect the eluent respectively, and blow the eluent with nitrogen until the methanol is completely volatilized, so as to obtain the HLB solid phase extraction column enriched sample and the PPL solid phase extraction column enriched sample respectively for the subsequent FT-ICR MS detection.

8. The detection and analysis method according to claim 1, wherein: The molecular formulas of organic molecules were matched by two FT-ICR MS detection data through the ultra-high resolution mass spectrometry matching platform FTMSAnalysis for dissolved organic matter developed based on Gaussian distribution alignment algorithm.

9. The detection and analysis method according to claim 8, wherein: For the same sample, the union of the molecules matched by the HLB column and PPL column is the total halogenated dissolved organic matter in the sample. The halogenated dissolved organic matter molecules with the same molecular formula are calculated only once, and then the types, distribution and characteristics of the halogenated dissolved organic matter in the sample are visualized and analyzed through the Sankey diagram.

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