Method for detecting various perfluorinated compounds in water environment

Abstract

The invention discloses a method for detecting multiple perfluorinated compounds in a water environment. The method comprises the steps of sample collection and preservation, sample pretreatment and LC-MS / MS detection. According to the invention, trace detection is carried out on common perfluorinated compounds in a water environment by adopting solid-phase extraction-liquid chromatography-electrospray-tandem triple quadrupole mass spectrometer, a more perfect and comprehensive LC-MS / MS detection method for multi-medium concentration of perfluorinated compounds is provided, and on the premise that the recovery rate and the accuracy of a detection result are ensured, the detection efficiency is improved. The sample pretreatment modes in different media are optimized and adjusted, so that the experiment process is more convenient and faster, time and labor are saved, the use of traditional glass material consumables is avoided, and the experiment error is reduced; meanwhile, the method disclosed by the invention is wider in application range, can meet trace detection of perfluorinated compounds in surface water, underground water, domestic sewage, industrial wastewater, river sediment and residual sludge of a sewage plant, and provides data support for quality supervision and risk early warning in a water environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental detection, and particularly relates to a method for detecting multiple perfluorinated compounds in water environment. Background Art

[0002] Per- and polyfluoroalkyl substances (PFASs) are a class of new persistent organic pollutants (POPs) that have attracted international attention. Specifically, they refer to organic compounds in which all hydrogen atoms connected to carbon atoms in the compound molecule are replaced by fluorine atoms, and the terminal has functional groups such as -COOH, forming an overall organic compound with a C n F 2n+1 —group. PFASs have special properties such as high thermal stability, chemical stability, and surface activity. They are widely used as pesticides, surfactants, lubricants, etc. in industrial, agricultural, and commercial fields, and thus enter the environment in large quantities. Currently, they have been commonly detected in various environmental media such as drinking water, surface water, groundwater, and sediment. Due to the extremely stable nature of PFASs, they are not easily degraded and are easily bioaccumulated through the food chain, posing a threat to human health and the ecological environment. Recent studies have found that the occurrence of diseases such as cancer, obesity, immunosuppression, and endocrine disorders is related to PFASs. Therefore, it is very important to establish a stable, accurate, and rapid analytical detection method for PFASs.

[0003] After the collection of PFASs in the multi-media environment, the LC-MS / MS detection method is often used to achieve separation and quantification. The LC-MS / MS detection method has become the mainstream detection technology for PFASs at present because of its advantages such as no need for derivatization treatment, high detection efficiency, and ability to meet the intensity requirements for quantitative analysis of trace pollutants. However, the existing LC-MS / MS method will be interfered by the background during the detection process, and there is still room for optimization in terms of applicable range, detection speed, and sensitivity. Therefore, it is very necessary to develop a detection method for multiple perfluorinated compounds in water environment that uses LC-MS / MS, is more convenient and fast, saves time and effort, ensures the recovery rate, and has accurate detection results. Summary of the Invention

[0004] To solve the above technical problems, the purpose of the present invention is to provide a method for detecting multiple perfluorinated compounds in water environment. This method optimizes the sample pretreatment method and the detection conditions on the machine, making the processing and operation process simple and convenient, the sample detection and analysis time shorter, the detection limit low, and the detection precision and accuracy higher, with a wide applicable range.

[0005] The purpose of the present invention is achieved as follows, including the following steps: S1. Sample collection and preservation: Collect water samples from the water body, seal and preserve them in the refrigerator, with the preservation time not exceeding 7 days; collect surface sediment samples from the water body, seal and preserve them away from light in the refrigerator, with the preservation time not exceeding 10 days. S2. Sample pretreatment: Water samples: Filter the water samples, adjust the pH of the water samples to 6.8 - 7.0, add the internal standard working solution to the water samples, use the activated solid-phase extraction column (SPE) to load and enrich perfluorinated compounds (PFASs) in the water samples, then sequentially wash the solid-phase extraction column with water and ammonium acetate as the buffer solution, discard the washing solution, dry the solid-phase extraction column by pumping air, wash the solid-phase extraction column with methanol, discard the washing solution, and then elute the solid-phase extraction column with an ammonia-methanol mixed solution to obtain the eluate containing perfluorinated compounds. Blow the eluate to near dryness with a nitrogen blower, redissolve it in methanol, filter it, and wait for instrumental analysis. Sediment samples: Freeze-dry the sediment samples, add the internal standard working solution to the sediment samples, let them stand, then add a methanol-water mixed solution, after ultrasonic treatment and centrifugation, collect the extract after extraction, filter the extract, add water to the extract to obtain a liquid sample, adjust the pH of the liquid sample to 6.8 - 7.0, use the activated solid-phase extraction column to load and enrich perfluorinated compounds in the liquid sample, then sequentially wash the solid-phase extraction column with water and ammonium acetate as the buffer solution, discard the washing solution, dry the solid-phase extraction column by pumping air, wash the solid-phase extraction column with methanol, discard the washing solution, and then elute the solid-phase extraction column with an ammonia-methanol mixed solution to obtain the eluate containing perfluorinated compounds. Blow the eluate to near dryness with a nitrogen blower, redissolve it in methanol, filter it, and wait for instrumental analysis. S3. LC-MS / MS detection: Use liquid chromatography-tandem mass spectrometry to determine perfluorinated compounds, and obtain the concentration of perfluorinated compounds in the samples according to the standard curve. Liquid chromatography conditions: Chromatographic column: Shim-pack GIST C18-AQ (2.1 mm × 100 mm, 3 μm); Mobile phase: Phase A: 2 mmol / L ammonium acetate, Phase B: acetonitrile; Flow rate: 0.3 mL / min; Column temperature: 40 °C; Injection volume: 5 μL; Elution method: gradient elution; Among them, the proportions of the two mobile phases are changed at different times. Under the comparison of interference, while shortening the sample measurement time, ensure that different PFASs are eluted and separated at different times as much as possible, with a short, stable, symmetric peak shape and no tailing. Triple quadrupole mass spectrometer mass conditions: Ion source scan mode: electrospray negative ion mode; Monitoring mode: MRM; Nitrogen is used as the carrier gas; Drying gas temperature: 250 °C; Drying gas flow rate: 10.0 L / min; Sheath gas temperature: 300 °C; Sheath gas flow rate: 10 L / min; Capillary voltage: 3000 V.

[0006] Among them, the containers used in each link are all made of polypropylene, which avoids the adsorption of PFASs by glassware and the release of PFASs from fluorine-containing containers.

[0007] Among them, the standard curve data are shown in Table 2; Table 2: Standard Curve Data .

[0008] In step S1, a pre-washed and dried sampling bottle is used for water sample collection. The sampling bottle cannot be pre-washed with the water sample before sampling to prevent contamination or adsorption of the sample.

[0009] Preferably, the perfluorinated compounds include one or more of perfluorobutyric acid, perfluorovaleric acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorooctadecanoic acid, perfluorobutane sulfonic acid, perfluorohexane sulfonic acid, perfluorooctane sulfonic acid, and perfluorodecane sulfonic acid.

[0010] Preferably, when collecting the water sample in step S1, the sampling bottle is completely filled without leaving air bubbles; if there is residual chlorine in the water, 40 mg of thiosulfate is added to each liter of water to remove chlorine, and a blank control sample is collected during on-site sampling.

[0011] Preferably, in step S2: When treating the water sample: adding the internal standard working solution to the water sample specifically means adding 50 μL of 0.2 μg / mL internal standard working solution to 500 mL of water sample; the flow rate of the sample through the solid-phase extraction column is 3 mL / min to 5 mL / min; the solid-phase extraction column is rinsed successively with 4 mL to 6 mL of water and 4 mL to 12 mL of ammonium acetate as a buffer solution; the air-drying time is 10 min; rinsing the solid-phase extraction column with methanol specifically means rinsing the solid-phase extraction column with 4 mL to 8 mL of methanol at a flow rate of 1 mL / min to 3 mL / min; eluting the solid-phase extraction column with an ammonia-methanol mixed solution specifically means eluting the solid-phase extraction column with 4 mL to 6 mL of ammonia-methanol mixed solution at a flow rate of 1 mL / min to 3 mL / min; re-dissolving in methanol means making the volume up to 1 ml with methanol; filtering using a 0.22 μm filter membrane, and the sample can be stored at 4 °C for testing; When processing sediment samples: adding the internal standard working solution to the sediment samples specifically means adding 50 μL of the 0.2 μg / mL internal standard working solution to 2 g of sediment samples (the samples are obtained by cold drying, grinding, and passing through a 60-mesh sieve, ensuring that PFASs in the sediment do not change and facilitating detection); standing specifically means standing for 24 h; the amount of methanol-water mixed solution is 10 ml; the ultrasonic time is 30 min, and the temperature during ultrasonic treatment is controlled at 50 °C - 60 °C; centrifugation is at 4000 r / min for 10 min; the supernatant collected by ultrasonic treatment and centrifugation is repeated three times, and the extracts are combined; 80 ml of water is added to the extract to obtain a liquid sample; the flow rate of the sample through the solid-phase extraction column is 3 mL / min - 5 mL / min; 4 mL - 6 mL of water and 4 mL - 12 mL of ammonium acetate are used as buffer solutions to wash the solid-phase extraction column in sequence; the air extraction and drying time is 10 min; washing the solid-phase extraction column with methanol specifically means washing the solid-phase extraction column with 4 mL - 8 mL of methanol at a flow rate of 1 mL / min - 3 mL / min; eluting the solid-phase extraction column with an ammonia-methanol mixed solution specifically means eluting the solid-phase extraction column with 4 mL - 6 mL of ammonia-methanol mixed solution at a flow rate of 1 mL / min - 3 mL / min; redissolving in methanol means making the volume up to 1 ml with methanol; filtering using a 0.22 μm filter membrane, and the sample can be stored at 4 °C for further testing.

[0012] Preferably, the internal standard working solution is a mixture of 13 C 4 -PFOA and 13 C 4 -PFOS, and these isotope-labeled substances are used as PFASs recovery rate indicators. While being fully miscible with the sample, they are also stable enough not to chemically react with the compounds in the sample, can correct for the losses during sample pretreatment, and achieve accurate quantification of the PFASs concentration in the sample.

[0013] Preferably, the activation of the solid-phase extraction column in step S2 is specifically as follows: the solid-phase extraction column is activated with 4 mL - 6 mL of 0.1% ammonia-methanol mixed solution, 4 mL - 6 mL of methanol, and 4 mL - 6 mL of ultrapure water in sequence at a flow rate of 2 mL / min - 5 mL / min; Preferably, the solid-phase extraction column used is a WAX solid-phase extraction column. The WAX extraction column is a weak anion exchange column and has a good enrichment effect on PFASs.

[0014] Preferably, the elution program during gradient elution in step S3 is shown in Table 1; Table 1: Liquid chromatography gradient elution program table .

[0015] Advantages of the present invention: The present invention uses solid-phase extraction - liquid chromatography - electrospray - triple quadrupole tandem mass spectrometry to perform trace detection on 17 common perfluorinated compounds (PFASs) in the water environment, providing a more complete and comprehensive LC-MS / MS detection method for PFASs multi-media concentrations. On the premise of ensuring the recovery rate and the accuracy of the detection results, the sample pretreatment methods in different media are optimized and adjusted, making the experimental process more convenient, faster, time-saving and labor-saving, avoiding the use of traditional glass material consumables, and reducing experimental errors; at the same time, the method of the present invention has a wider application range, and can meet the trace detection of PFASs in surface water, groundwater, domestic sewage, industrial wastewater, river bottom sediment and sewage treatment plant excess sludge, providing data support for quality supervision and risk warning in the water environment. Brief Description of the Drawings

[0016] Figure 1 It is a flow schematic diagram of the method of the present invention; Figure 2 It is a chromatogram of 17 perfluorinated compounds of the detection result of Example 1. Detailed Embodiments

[0017] The present invention will be further described below in conjunction with the drawings, but the present invention is not limited in any way. Any transformation or replacement based on the teachings of the present invention belongs to the protection scope of the present invention.

[0018] Example 1 Using the detection method of various perfluorinated compounds in the water environment of this example, perfluorobutyric acid, perfluorovaleric acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorooctadecanoic acid, perfluorobutane sulfonic acid, perfluorohexane sulfonic acid, perfluorooctane sulfonic acid, perfluorodecane sulfonic acid, a total of 17 perfluorinated compounds are detected; specifically including the following steps: S1. Sample collection and preservation: Collect the water sample of the water body and seal it in a 500 mL polypropylene plastic bottle. After collection, it should be transported back to the laboratory as soon as possible and refrigerated at a temperature below 4 °C, and the preservation time should not exceed 7 days; when collecting the water sample of the water body, fill the sampling bottle completely without leaving air bubbles; if there is residual chlorine in the water, add 40 mg of sodium thiosulfate per liter of water to remove chlorine, and collect a blank control sample at the same time during on-site sampling; collect the surface sediment sample of the water body and seal it in a clean stoppered ground glass brown glass bottle. After transporting it to the laboratory, refrigerate it at a temperature below 4 °C, protect it from light and seal it for preservation, and the preservation time should not exceed 10 days; the sample needs to be analyzed within 28 days; S2. Sample pretreatment: Water sample: Filter the water sample, adjust the pH of the water sample to 7.0, add 50 μL of 0.2 μg / mL internal standard working solution to 500 mL of the water sample, and the internal standard working solution is13 C 4 - mixture of PFOA and 13 C 4 - PFOS. The activated WAX solid-phase extraction column was used to enrich perfluorinated compounds in the water sample by loading. The flow rate was 5 mL / min. Then, 6 mL of water and 8 mL of ammonium acetate were used as buffer solutions to wash the solid-phase extraction column in sequence. The washing solutions were discarded. The solid-phase extraction column was dried by pumping air for 10 min. The solid-phase extraction column was washed with 8 mL of methanol at a flow rate of 2 mL / min. The washing solutions were discarded. Then, the solid-phase extraction column was eluted with 6 mL of ammonia-methanol mixed solution at a flow rate of 2 mL / min to obtain an eluate containing perfluorinated compounds. The eluate was blown to near dryness with a nitrogen blower, redissolved in methanol, and made up to 1 mL. After filtration through a 0.22 μm filter membrane, it was ready for on-machine detection; Sediment sample: The sediment sample was freeze-dried. 50 μL of internal standard working solution with a concentration of 0.2 μg / mL was added to 2 g of the sediment sample. The internal standard working solution was 13 C 4 - mixture of PFOA and 13 C 4 - PFOS. After standing for 24 h, 10 mL of methanol-water mixed solution was added. After ultrasonic treatment for 30 min with the temperature controlled at 55 °C during ultrasonic treatment, centrifugation was carried out at 4000 r / min for 10 min. The process of ultrasonic treatment and centrifugation to collect the supernatant was repeated three times. The extracts were combined and filtered. 80 mL of water was added to the extract to obtain a liquid sample. The pH of the liquid sample was adjusted to 7.0. The activated WAX solid-phase extraction column was used to enrich perfluorinated compounds in the liquid sample by loading. The flow rate was 5 mL / min. Then, 6 mL of water and 8 mL of ammonium acetate were used as buffer solutions to wash the solid-phase extraction column in sequence. The washing solutions were discarded. The solid-phase extraction column was dried by pumping air for 10 min to remove the residual water in the column. The solid-phase extraction column was washed with 8 mL of methanol at a flow rate of 2 mL / min. The washing solutions were discarded. Then, the solid-phase extraction column was eluted with 6 mL of ammonia-methanol mixed solution at a flow rate of 2 mL / min to obtain an eluate containing perfluorinated compounds. The eluate was blown to near dryness with a nitrogen blower, redissolved in methanol and made up to 1 mL. After filtration through a 0.22 μm filter membrane, it was ready for on-machine detection; The activation of the solid-phase extraction column in step S2 was specifically as follows: The solid-phase extraction column was activated successively with 6 mL of 0.1% ammonia-methanol mixed solution, 6 mL of methanol and 6 mL of ultrapure water at a flow rate of 2 mL / min; during the activation process, it should be ensured that the packing of the solid-phase extraction column was not exposed to air; S3, LC-MS / MS detection: Perfluorinated compounds were determined by liquid chromatography-tandem mass spectrometry, and the concentration of perfluorinated compounds in the sample was obtained according to the standard curve; Liquid chromatography conditions: Chromatographic column: Shim-pack GIST C18-AQ (2.1 mm × 100 mm, 3 μm); Mobile phase: Phase A: 2 mmol / L ammonium acetate, Phase B: acetonitrile; Flow rate: 0.3 mL / min; Column temperature: 40 °C; Injection volume: 5 μL; Elution method: gradient elution; The elution program during the gradient elution in step S3 is shown in Table 1; Table 1: Liquid chromatography gradient elution program table Triple quadrupole mass spectrometer (the instrument is Shimadzu LCMS-8050 triple quadrupole mass spectrometer) mass spectrometry conditions: Ion source scan mode: electrospray negative ion mode; Monitoring mode: MRM; Nitrogen is the carrier gas; Drying gas temperature: 250 °C; Drying gas flow rate: 10.0 L / min; Sheath gas temperature: 300 °C; Sheath gas flow rate: 10 L / min; Capillary voltage: 3000 V; The multiple reaction ion detection parameters for the mass spectrometry of 17 PFASs are shown in Table 3; Table 3: Multiple reaction ion detection parameters for the mass spectrometry of 17 PFASs The experimental results are shown in Table 4, attached Figure 2 ; Table 4: Detection results of 17 PFASs; 。

[0019] Example 2 The detection method of various perfluorinated compounds in the water environment of this example is based on Example 1. The differences from Example 1 are: During the pretreatment of the water sample in step S2, the flow rate of the water sample through the solid-phase extraction column is 3 mL / min. The solid-phase extraction column is rinsed successively with 4 mL of water and 4 mL of ammonium acetate as the buffer solution, rinsed with 4 mL of methanol at a flow rate of 1 mL / min, and eluted with 4 mL of ammonia-methanol mixed solution at a flow rate of 1 mL / min. During the pretreatment of the sediment sample, the ultrasonic temperature is 60 °C, the flow rate of the liquid sample through the solid-phase extraction column is 3 mL / min. The solid-phase extraction column is rinsed successively with 4 mL of water and 4 mL of ammonium acetate as the buffer solution, rinsed with 4 mL of methanol at a flow rate of 1 mL / min, and eluted with 4 mL of ammonia-methanol mixed solution at a flow rate of 1 mL / min; The activation of the solid-phase extraction column is specifically as follows: The solid-phase extraction column is activated successively with 4 mL of 0.1% ammonia-methanol mixed solution, 4 mL of methanol, and 4 mL of ultrapure water at a flow rate of 5 mL / min.

[0020] Example 3 The detection method of various perfluorinated compounds in the water environment of this embodiment is based on Embodiment 1. The difference from Embodiment 1 is that when pretreating the water sample in step S2, the flow rate of the water sample through the solid-phase extraction column is 4 mL / min. The solid-phase extraction column is sequentially rinsed with 5 mL of water and 12 mL of ammonium acetate as a buffer solution, rinsed with 6 mL of methanol at a flow rate of 3 mL / min, and eluted with 5 mL of ammonia-methanol mixed solution at a flow rate of 3 mL / min. When pretreating the sediment sample, the ultrasonic temperature is 50 °C, the flow rate of the liquid sample through the solid-phase extraction column is 4 mL / min. The solid-phase extraction column is sequentially rinsed with 5 mL of water and 12 mL of ammonium acetate as a buffer solution, rinsed with 6 mL of methanol at a flow rate of 3 mL / min, and eluted with 5 mL of ammonia-methanol mixed solution at a flow rate of 3 mL / min. The activation of the solid-phase extraction column is specifically as follows: The solid-phase extraction column is activated with 5 mL of 0.1% ammonia-methanol mixed solution, 5 mL of methanol, and 5 mL of ultrapure water in sequence at a flow rate of 3.5 mL / min.

Claims

1. A method for detecting multiple perfluorinated compounds in an aqueous environment, characterized in that The following steps are involved: S1. Sample collection and storage: Collect water samples from water bodies and store them in a sealed container and refrigerate them for no more than 7 days; collect surface sediment samples from water bodies and store them in a sealed container and refrigerate them in a dark place for no more than 10 days; S2. Sample pretreatment: Water sample: filter the water sample, adjust the pH value of the water sample to 6.8-7.0, add the internal standard solution to the water sample, load the activated solid phase extraction column to enrich the perfluorinated compounds in the water sample, then use water and ammonium acetate as buffer to elute the solid phase extraction column in turn, discard the eluent, vacuum dry the solid phase extraction column, elute the solid phase extraction column with methanol, discard the eluent, and then elute the solid phase extraction column with ammonia-methanol mixed solution to obtain the eluent containing perfluorinated compounds, blow the eluent to nearly dryness with a nitrogen blower, redissolve it in methanol, filter it and wait for machine detection; Sediment samples: freeze-dry the sediment samples, add the internal standard solution to the sediment samples, let stand, add a methanol-water mixed solution, perform ultrasonic and centrifugation, collect the extract after extraction, filter the extract, add water to the extract to obtain a liquid sample, adjust the pH of the liquid sample to 6.8-7.0, load the activated solid phase extraction column to enrich the perfluorinated compounds in the liquid sample, then use water and ammonium acetate as buffers to elute the solid phase extraction column in turn, discard the eluent, dry the solid phase extraction column, elute the solid phase extraction column with methanol, discard the eluent, and then elute the solid phase extraction column with an ammonia-methanol mixed solution to obtain an eluent containing perfluorinated compounds, blow the eluent to near dryness with a nitrogen blower, redissolve it in methanol, filter it, and wait for machine detection; S3, LC-MS / MS detection: Liquid chromatography-tandem mass spectrometry is used to determine perfluorinated compounds, and the concentration of perfluorinated compounds in the sample is obtained according to the standard curve; Liquid chromatography conditions: chromatographic column: Shim-pack GISTC18-AQ (2.1 mm × 100 mm, 3 μm); mobile phase: phase A: 2 mmol / L ammonium acetate, phase B: acetonitrile; flow rate: 0.3 mL / min; Column temperature: 40°C; injection volume: 5 μL; elution method: gradient elution; Mass spectrometry conditions of triple quadrupole mass spectrometer: ion source scanning mode: electrospray negative ion mode; monitoring mode: MRM; nitrogen as carrier gas; drying gas temperature: 250°C; drying gas flow rate: 10.0 L / min; sheath gas temperature: 300°C; sheath gas flow rate: 10 L / min; capillary voltage: 3000 V.

2. The method for detecting multiple perfluorinated compounds in an aqueous environment according to claim 1, characterized in that The perfluorinated compound includes one or more of perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorooctadecanoic acid, perfluorobutane sulfonic acid, perfluorohexane sulfonic acid, perfluorooctane sulfonic acid, and perfluorodecane sulfonic acid.

3. The method for detecting multiple perfluorinated compounds in an aqueous environment according to claim 1, characterized in that When collecting water samples in step S1, fill the sampling bottle completely without leaving any bubbles; if there is residual chlorine in the water, add 40 mg of thiosulfuric acid per liter of water to remove the chlorine, and collect a blank control sample at the same time when sampling on site.

4. The method for detecting multiple perfluorinated compounds in an aqueous environment according to claim 1, characterized in that In step S2: When treating water samples: add internal standard solution to the water sample, specifically add 50μL of 0.2μg / mL internal standard solution to 500mL water sample; the flow rate of the sample through the solid phase extraction column is 3mL / min~5mL / min; use 4mL~6mL water and 4mL~12mL ammonium acetate as buffers to elute the solid phase extraction column in turn; the vacuum drying time is 10min; elute the solid phase extraction column with methanol, specifically use 4mL~8mL methanol at a flow rate of 1mL / min~3mL / min to elute the solid phase extraction column; elute the solid phase extraction column with ammonia-methanol mixed solution, specifically use 4mL~6mL ammonia-methanol mixed solution at a flow rate of 1mL / min~3mL / min to elute the solid phase extraction column; redissolve in methanol with methanol to make up to 1ml; filter with a 0.22μm filter membrane; When processing sediment samples: add internal standard solution to the sediment sample, specifically add 50μL of 0.2μg / mL internal standard solution to 2g sediment sample; let it stand for 24h; use 10ml of methanol-water mixed solution; ultrasonic time 30min, the temperature during ultrasonication is controlled at 50℃~60℃; centrifugation is 4000r / min centrifugation for 10min; repeat ultrasonication and centrifugation three times to collect the supernatant, and combine to obtain the extract; add 80ml of water to the extract to obtain a liquid sample; the flow rate of the sample through the solid phase extraction column is 3mL / min~5mL / mi n; Use 4mL~6mL water and 4mL~12mL ammonium acetate as buffer to elute the solid phase extraction column in turn; vacuum drying time is 10min; elute the solid phase extraction column with methanol, specifically use 4mL~8mL methanol at a flow rate of 1mL / min~3mL / min; elute the solid phase extraction column with a mixed solution of ammonia water and methanol, specifically use 4mL~6mL ammonia water and methanol mixed solution at a flow rate of 1mL / min~3mL / min; re-dissolve in methanol, make up to 1ml with methanol; filter using a 0.22μm filter membrane.

5. The method for detecting multiple perfluorinated compounds in an aqueous environment according to claim 1 or 4, characterized in that The internal standard solution used is 0.2 μg / mL 13 C4-PFOA and 13 A mixture of C4-PFOS.

6. The method for detecting multiple perfluorinated compounds in an aqueous environment according to claim 1, characterized in that The specific steps of S2 step for solid phase extraction column activation are as follows: 4 mL to 6 mL of 0.1% ammonia-methanol mixed solution, 4 mL to 6 mL of methanol and 4 mL to 6 mL of ultrapure water are used to activate the solid phase extraction column at a flow rate of 2 mL / min to 5 mL / min.

7. The method for detecting multiple perfluorinated compounds in an aqueous environment according to claim 1, characterized in that The solid phase extraction columns all use WAX ​​solid phase extraction columns.

8. The method for detecting multiple perfluorinated compounds in an aqueous environment according to claim 1, characterized in that The elution program for the gradient elution in step S3 is shown in Table 1; Table 1: Liquid chromatography gradient elution program 。

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