Method for detecting short-chain / ultra-short-chain PFAS in multiple environmental media of surface water-underground water interaction system

Abstract

The invention discloses a method for detecting short-chain / ultra-short-chain PFAS in various environmental media of a surface water-underground water interaction system. The method provided by the invention comprises the following steps: pretreating a sample; performing solid-phase extraction on the obtained sample to obtain a loaded sample; and detecting the obtained loading sample by using a liquid chromatography-mass spectrometry technology to obtain the PFAS content. The method provided by the invention has the advantages of wide detection range, high recovery rate, simplicity and convenience in operation, high sensitivity and low detection limit, and is suitable for analyzing trace PFAS in an environmental sample.

Description

Technical Field

[0001] The present invention belongs to the field of analytical technology, and specifically relates to a method for detecting short-chain / ultra-short-chain PFAS in various environmental media of a surface water-groundwater interaction system. Background Art

[0002] Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a broad class of man-made chemicals characterized by partial or complete replacement of hydrogen atoms on the carbon chain by fluorine atoms, forming an extremely stable carbon-fluorine bond. Due to its hydrophobicity and stability, PFAS has been used in many industries. At present, PFAS have been detected to varying degrees in surface water, groundwater, tap water, soil, sediment and sewage sludge, even in the inaccessible Arctic region, and in the tissues and blood of various organisms. Humans can be exposed to PFAS through drinking water, dust, food, and contact with contaminated soil or sediment. PFAS is bioaccumulative, can be transmitted and amplified in the food chain, and is difficult to decompose, so it can accumulate in the human body and stay for a long time.

[0003] At present, countries around the world have developed PFAS detection methods, but most detection targets focus on long-chain PFAS (PFAS with carbon chains greater than or equal to 8). The quantitative detection of short-chain PFAS and even ultra-short-chain PFAS (short-chain PFAS: carbon chains between 4-7, ultra-short-chain PFAS: carbon chains between 1-3) is still in its infancy and has many shortcomings, such as small scope of application and low sensitivity. At the same time, the environmental media of the surface water-groundwater interaction system are complex and diverse, which further increases the difficulty of PFAS detection.

[0004] As the production and use of long-chain PFAS such as perfluorooctanoic acid and perfluorooctane sulfonic acid are explicitly banned, the use of short-chain / ultra-short-chain PFAS alternatives has increased significantly. Due to their physical and chemical properties, they are more easily spread in the environment, are potentially toxic to organisms, and are difficult to remove through traditional water treatment technologies. It is necessary to strengthen the supervision and detection of short-chain and ultra-short-chain PFAS. Therefore, how to efficiently and accurately detect the content of short-chain / ultra-short-chain PFAS in various environmental media in the surface water-groundwater interaction system is one of the difficulties in PFAS detection technology at this stage. Summary of the invention

[0005] The purpose of the present invention is to provide an efficient detection method for short-chain / ultra-short-chain PFAS in various environmental media in the surface water-groundwater interaction system. The method has the advantages of simple operation, wide detection range, high recovery rate, high sensitivity and low detection limit, and is suitable for the analysis of trace PFAS in complex environmental medium samples.

[0006] In the present invention, the surface water-groundwater interaction system refers to the water quantity and water quality exchange process between surface water bodies (such as rivers, lakes, wetlands, etc.) and groundwater.

[0007] In the present invention, the environmental medium in the surface water-groundwater interaction system refers to the interaction carrier or medium between soil, rock, sediment and other substances. They play an important role in transmission and transformation in the process of water flow, material change, water quality change and so on.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides a method for detecting short-chain / ultra-short-chain PFAS in various environmental media of a surface water-groundwater interaction system, comprising the following steps:

[0010] S1, pre-treating the sample;

[0011] S2, extracting the sample obtained in step S1 to obtain a sample for use in the machine;

[0012] S3, testing the sample obtained in step S2, and calculating the PFAS content;

[0013] The PFAS are short-chain or ultra-short-chain perfluoroalkyl and polyfluoroalkyl substances;

[0014] The short-chain PFAS refers to PFAS with a carbon chain between 4 and 7.

[0015] The ultra-short-chain PFAS refers to PFAS with a carbon chain between 1 and 3.

[0016] Specifically, the short-chain / ultra-short-chain PFAS include: PFBA, PFPeA, PFHpA, PFBS, PFPeS, PFHxS, PFHpS, 4:2FTS, HFPO-DA, TFA, PFEtS, MPFBA, MPFPeA, MPFHxA, MPFHpA, MPFBS, MPFHxS, MPFOS, and M4:2FTS.

[0017] The sample is a sample in a surface water-groundwater interaction system.

[0018] The extraction is solid phase extraction.

[0019] The detection method is liquid chromatography-mass spectrometry technology.

[0020] In the present invention, in step S1, the sample is a water sample or a sediment sample.

[0021] The water body is groundwater, such as a spring leak, an underground river, or surface water, such as a river.

[0022] The sediment is soil or river bottom sediment.

[0023] In the present invention, the sample is a water sample, and the pretreatment of the sample is performed according to the following operations: filtering the water sample, adding PFAS internal standard, and adjusting the pH value to 6-8; wherein the pore size of the filter membrane used for the filtration is 0.22 μm, which can remove suspended matter and impurities in the water and prevent clogging of the instrument pipeline.

[0024] The amount of the PFAS internal standard added is: 10 ng of internal standard is added to every 1 L of water sample.

[0025] In the present invention, the sample is a water sample, and the extraction column used in the extraction is an Oasis@WAX extraction column.

[0026] The sample is a water sample, and the eluent used for the extraction is 0.1% ammonia water-methanol.

[0027] In one embodiment of the present invention, the extraction of the water sample is carried out according to the following operation: the Oasis@WAX extraction column is activated with 0.1% ammonia-methanol, methanol and ultrapure water in sequence, the water sample is passed through the extraction column, and the extraction column is eluted with ammonium acetate solution and ultrapure water; the extraction column is dried under negative pressure, and then the extraction column is eluted with methanol and 0.1% ammonia-methanol in sequence at a flow rate of 1 ml / min to 3 ml / min, the eluate is collected in a centrifuge tube, blown almost dry with nitrogen, and fixed to volume with methanol-water solution.

[0028] In the present invention, the sample is sediment, and the pretreatment of the sample is performed according to the following operations: homogenizing the sediment sample, adding a PFAS internal standard, ultrasonic extraction, centrifugation, taking the supernatant, and concentrating; wherein the homogenization treatment makes the particle size of the sample ≥100 mesh; the amount of the PFAS internal standard added is: 1 ng of the internal standard is added to every 1 g of the sediment sample;

[0029] The conditions of the ultrasonic extraction are: 25° C., 40 KHz.

[0030] Preferably, the extractant used in the ultrasonic extraction is: a methanol solution containing 100 mM ammonium acetate. Studies have found that ammonium acetate can enhance the interaction between the hydrophilic part of PFAS and water, thereby desorbing PFAS from the soil surface or particles.

[0031] The centrifugal conditions are: centrifugation on a shaker at 25°C and 5000 r / min;

[0032] The concentration conditions are as follows: at 40° C. and under nitrogen protection, the liquid volume is concentrated to 2 mL.

[0033] The centrifugal conditions were as follows: centrifugation on a shaker at 25° C. and 5000 r / min for 10 min.

[0034] The concentration conditions are as follows: concentrating the sample volume to 2 mL at 40° C. under high-purity nitrogen.

[0035] In the present invention, the sample is sediment, and the extraction column used in the extraction is a graphitized carbon solid phase extraction column.

[0036] In the present invention, the sample is sediment, and the eluent used for the extraction is methanol.

[0037] In one embodiment of the present invention, the solid phase extraction of the sediment sample is carried out according to the following operation: the extraction column is activated with methanol, the sediment sample is loaded into a small column, and methanol is used to elute at a flow rate of 1 ml / min to 3 ml / min, the eluate is collected in a centrifuge tube, blown nearly dry with nitrogen, and fixed to volume with 30 wt% methanol aqueous solution.

[0038] In the present invention, in step S3, the detection conditions of the liquid chromatography-mass spectrometry technology are as follows:

[0039] Liquid chromatography conditions:

[0040] Chromatographic column: ACQUITY UPLC BEH C18 column, 1.7 μm, 2.1 mm × 50 mm;

[0041] Mobile phase: Phase A is 0.005 mol / L ammonium acetate aqueous solution, and phase B is methanol;

[0042] Flow rate: 0.3ml / min;

[0043] Injection volume: 10 μL;

[0044] Column temperature: 40°C;

[0045] Table 1: Mobile phase gradient elution program.

[0046] Table 1 Mobile phase gradient elution program

[0047]

[0048] Mass spectrometry conditions:

[0049] Table 2 Mass spectrometry conditions of perfluorinated compounds and their internal standards

[0050]

[0051] In the present invention, the calculation of the PFAS content is performed according to the following operation:

[0052] (1) The standard curve was established by the following operation: the PFAS standard solution was diluted with a 30 wt % methanol aqueous solution to prepare a series of standard solutions of 0, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, and 200 μg / L, and the standard curve was drawn;

[0053] Table 3 Standard curve

[0054] Compound Standard curve <![CDATA[R 2 ]]> PFBA y=0.07625x+0.00262 0.99817 PFA y=0.07389x+0.00452 0.99270 PFh y=0.11757x+0.00447 0.99476 PFHpA y=0.10859x+0.00331 0.98889 PFBS y=0.09042x+7.75552e-5 0.99627 PFS y=0.01872x+2.18032e-5 0.99649 PFh y=0.08653x+3.51707e-4 0.99726 PfH y=0.09577x+6.68881e-4 0.99821 4:2FTS y=0.16103x+2.42461e-4 0.99730 HFPO-DA y=0.00201x+2.03359e-4 0.99493 TFA y=0.25141x+7.68555e-4 0.99037 Pf y=0.30955x+6.87965e-5 0.99756

[0055] (2) The PFAS content is calculated according to the following operation: the ratio of the peak area of ​​each target substance to be measured in the sample to its corresponding internal standard peak area is substituted into the standard curve to obtain the injection mass concentration of each target substance to be measured; the injection mass concentration is then substituted into the following formula to calculate the mass concentration of the target substance to be measured in the sample, and the measurement result is expressed as the arithmetic mean of parallel measurements.

[0056] The calculation formula of the PFAS content is as follows:

[0057]

[0058] in:

[0059] ρ—mass concentration of each target substance to be measured in the sample, ng / L;

[0060] ρ1—injection mass concentration, μg / L;

[0061] V1—final fixed volume of the sample, ml;

[0062] V—sampling volume, L.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] This method uses solid phase extraction and liquid chromatography-mass spectrometry technology to achieve quantitative analysis of different short-chain and ultra-short-chain PFAS in a variety of environmental media, solving the problem of insufficient sensitivity of existing detection methods in detecting short-chain / ultra-short-chain PFAS. It can effectively detect 12 types of PFAS (including 10 short-chain and 2 ultra-short-chain), and the recovery rates are between 70% and 140%. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 These are the sampling points for surface water and groundwater in Example 1. DETAILED DESCRIPTION

[0066] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

[0067] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0068] Unless otherwise specified, the reagents, materials, instruments, etc. used in the following examples can be obtained from commercial sources.

[0069] Example 1: Detection of PFAS in water

[0070] Here are the steps:

[0071] (1) All surface water and groundwater samples were filtered through a 0.22 μm filter membrane to remove suspended solids and impurities in the water and prevent impurities from entering the instrument and clogging the pipeline. 10 ng PFAS internal standard was added, and the internal standard was added to correct the recovery rate and matrix effect in the subsequent quantitative analysis to ensure the accuracy of quantification.

[0072] in:

[0073] Groundwater samples: GW-2, GW-6, and GW-9 were collected from spring outcrops and underground rivers in the Hongfeng Lake area of ​​Guiyang City, Guizhou Province.

[0074] Surface water samples: SW-1, SW-2, SW-3, SW-4, SW-7, SW-9, SW-13, and SW-16 were collected from the confluence of Hongfeng Lake and its tributaries in Guiyang City, Guizhou Province, respectively.

[0075] (2) Use acetic acid or ammonia to adjust the pH of the water sample to 6-8, and activate the Oasis@WAX extraction column with 5 ml of 0.1% ammonia-methanol, 7 mL of methanol, and 10 mL of ultrapure water in sequence to fully expose the active sites on the surface of the extraction column and enhance its adsorption capacity. The water sample is passed through the extraction column at a flow rate of 8 mL / min to capture and concentrate PFAS on the extraction column so that these target substances can be detected more sensitively later.

[0076] Use 5ml 25mmol / L ammonium acetate solution and 12ml ultrapure water to rinse, remove impurities and other water-soluble components in the extraction column except PFAS, and discard the eluent. Dry the extraction column under negative pressure for 10min, and use 5ml methanol and 7mL 0.1% ammonia-methanol to elute the solid phase extraction column at a flow rate of 1ml / min to 3ml / min, and elute PFAS from the extraction column into the eluent, collect the eluent in a centrifuge tube, blow the eluted liquid nitrogen to dryness, and dilute to 1ml with methanol aqueous solution (30wt%) for subsequent liquid chromatography-mass spectrometry analysis.

[0077] (3) Test and results:

[0078] The detection conditions and calculation formula are the same as above.

[0079] Table 4 PFAS concentrations in groundwater (GW) and surface water (SW) (ng / L)

[0080] Target GW-2 GW-6 GW-9 SW-1 SW-2 SW-3 SW-4 SW-7 SW-9 SW-13 SW-16 PFBA 0.514 2.538 0.268 2.039 2.571 0.723 0.634 0.536 0.824 0.825 1.721 PFA 0.308 0.9 0.062 1.357 1.959 1.258 0.106 0.211 0.126 0.028 0.26 PFh 1.127 2.939 1.123 2.359 1.269 1.219 1.213 0.483 1.023 0.976 1.369 PFHpA 0.136 0.653 0.027 0.517 1.635 0.758 0.648 0.077 0.111 0.152 0.682 PFBS 0.11 0.366 0.323 8.683 0.637 0.293 0.47 0.865 0.673 0.173 1.003 PFS 0.383 0.152 0.524 0.129 0.286 0.124 0.34 0.174 0.169 0.247 0.082 PFh 0.089 0.064 0.186 0.115 0.109 0.063 0.664 0.263 0.348 0.201 0.054 PfH 0.285 0.061 0.826 0.073 0.139 0.103 0.384 0.402 1.196 0.428 0.148 4:2FTS ND ND ND ND ND ND ND ND ND ND ND HFPO-DA 0.226 0.152 0.093 1.571 1.407 1.345 0.468 2.911 0.406 1.873 1.871 TFA 2.576 0.507 2.594 0.898 0.85 0.262 0.696 1.008 0.274 0.382 0.91 Pf 0.004 0.009 0.007 0.003 0.014 0.007 0.007 0.009 0.014 0.011 0.004

[0081] Table 5 Recovery rate and RSD of PFAS in water samples

[0082] Target Recovery rate / % RSD PFBA 93.51 6.45％ PFA 78.93 12.51％ PFh 120.67 12.33％ PFHpA 123.07 16.36％ PFBS 99.16 5.08％ PFS 135.53 16.76％ PFh 89.67 15.85％ PfH 83.81 17.33％ 4:2FTS 100.19 11.46％ HFPO-DA 104.64 16.86％ TFA 126.54 15.49％ Pf 97.45 7.41％

[0083] It can be seen from the above table that the method provided by the present invention can effectively detect 12 types of PFAS (including 10 short-chain and 2 ultra-short-chain) in water bodies, with relatively high sensitivity (RSD 5.08%-17.33%), and the recovery rate is between 70%-140%.

[0084] Example 2: Detection of PFAS in sediments

[0085] Here are the steps:

[0086] (1) The soil sample was thoroughly mixed and dried, large fragments were manually picked out, and the soil was ground through a 100-mesh sieve for full homogenization. 2 g of soil sample was weighed and placed in a 15 mL centrifuge tube, 2 ng of PFAS internal standard was added, and then 5 ml of methanol was added. The mixture was shaken for 1 min, and then ultrasonically extracted for 30 min. Ultrasonic waves generated high-frequency vibrations to destroy soil particles, increase the contact surface between the target and the solvent, and promote the extraction of compounds. The sample was centrifuged on a shaker at 25 ° C and 5000 r / min for 10 min to precipitate the soil sample, and the supernatant was transferred to a new 15 mL centrifuge tube. 5 mL of methanol solution was added and the above extraction steps were repeated twice. The recovery rate of the target was improved through multiple extractions, and the supernatant was concentrated to reduce the solvent volume, enrich the target, and facilitate subsequent analysis. The obtained supernatant (about 15 ml) was concentrated to about 2 ml under high-purity nitrogen at 40 ° C to remove excess solvent, reduce the loss of the target, and make the sample more concentrated.

[0087] The soil samples were obtained from the bottom mud and sediment at the surface water sampling point described in Example 1.

[0088] (2) Purification with PestiCarb (graphitized carbon solid phase extraction column, 500 mg / 6 mL) column. The graphitized carbon column has high adsorption capacity and can effectively remove interfering substances while maintaining good retention of the target on the column to avoid target loss. First, 2 ml of methanol was passed through the extraction column three times for activation. The concentrate was loaded into the column and rinsed with 1 ml of methanol three times. The collected solution was blown to near dryness under high-purity nitrogen and fixed to 1 ml with methanol-water solution for analysis on the machine.

[0089] (3) Test and results:

[0090] The detection conditions and calculation formula are the same as above.

[0091] Table 6 Recovery rate and RSD of PFAS in sediment

[0092] Target Recovery rate / % RSD PFBA 110.98 7.58％ PFA 103.84 10.14％ PFh 139.04 16.30％ PFHpA 92.61 17.60％ PFBS 111.22 8.54％ PFS 130.73 12.70％ PFh 107.32 14.28％ PfH 108.91 15.25％ 4:2FTS 113.63 7.29％ HFPO-DA 99.69 14.71％ TFA 116.10 13.91％ Pf 111.03 15.67％

[0093] As can be seen from the above table, the method provided by the present invention can effectively detect 12 PFAS (including 10 short-chain and 2 ultra-short-chain) in sediments, with relatively high sensitivity (RSD7.29%-17.60%), and the recovery rate is between 90-140%.

[0094] Table 7 PFAS concentration in sediment (ng / L)

[0095] Target S1 S2 S3 S4 S5 S6 S7 PFBA 0.014 0.036 0.041 0.076 0.109 0.126 0.08 PFA 0.076 0.078 0.14 0.256 0.235 0.182 0.752 PFh 0.056 0.191 0.343 0.468 0.537 0.149 1.659 PFHpA 0.075 0.126 0.159 0.484 0.265 0.341 0.141 PFBS 0.005 0.036 0.098 0.15 0.159 0.341 0.37 PFS 0.03 0.085 0.137 0.079 0.398 0.66 0.995 PFh 0.012 0.064 0.026 0.0222 0.198 0.432 0.469 PfH 0.046 0.074 0.031 0.057 0.161 0.163 0.133 4:2FTS 0.009 0.008 0.081 0.211 0.083 0.487 0.26 HFPO-DA 0.503 1.994 3.77 3.21 1.481 1.588 3.255 TFA 1.051 1.431 2.749 4.33 4.322 2.209 7.013 Pf 0.001 0.005 0.009 0.048 0.045 0.233 0.046

[0096] Investigation of influencing factors

[0097] 1. Investigation of solid phase extraction column

[0098] This experiment investigated the effect of solid phase extraction columns Oasis@WAX and Oasis@HLB on the recovery of target PFAS. The steps are as follows:

[0099] Two types of solid phase extraction columns were used for spiking experiments. 10 ng of target PFAS was added to 1 L of ultrapure water. Except for the extraction columns, other experimental processes were exactly the same. The extraction performance of the two columns was compared by calculating the recovery rate.

[0100] The detection conditions and calculation formula are the same as above.

[0101] The results are shown in the following table.

[0102] Table 8 Effect of different solid phase extraction columns on target PFAS recovery

[0103]

[0104] From the results in the above table, it can be seen that the recovery rate of short-chain and ultra-short-chain PFAS by solid phase extraction column Oasis@WAX is significantly higher than that of extraction column Oasis@WAX.

[0105] 2. Investigation of eluent combination

[0106] This experiment investigated the effect of different eluent combinations on the recovery of target PFAS. The steps are as follows:

[0107] Three elution reagent combinations were selected: methanol-0.1% ammonia methanol combination, methanol-0.1% ammonia acetonitrile combination, and 0.1% ammonia methanol-0.1% ammonia acetonitrile combination. 10 ng of target PFAS was added to 1L ultrapure water. The experimental steps were the same except for the elution reagents. Each reagent was eluted with 4 ml. The elution performance of the three elution combinations was compared by calculating the recovery rate.

[0108] Table 9 Effect of different eluent combinations on target PFAS recovery

[0109]

[0110] It can be seen from the results in the above table that the recovery rate of the target PFAS is the best when the sample is eluted using methanol-0.1% ammonia methanol combination 1, and the recovery rate of ultra-short chain PFAS is poor when methanol-0.1% ammonia acetonitrile combination 2 and 0.1% ammonia methanol-0.1% ammonia acetonitrile combination 3 are used. Therefore, methanol-0.1% ammonia methanol combination 1 is selected as the elution reagent of the present invention.

[0111] 3. Limit of detection and limit of quantification

[0112] The detection limits and quantification limits of the water samples and sediments were obtained by using the methods of Examples 1 and 2. The results are as follows.

[0113] Table 10 Detection limits and quantification limits of water samples and sediments

[0114]

[0115] In summary, from the above test results, it can be seen that the detection method provided by the present invention has the advantages of simple operation, wide detection range, high recovery rate, high sensitivity and low detection limit, and is suitable for the analysis of trace short-chain / ultra-short-chain PFAS in water and soil in surface water-groundwater interaction systems.

[0116] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for detecting PFAS, comprising the following steps: S1, pre-treating the sample; S2, extracting the sample obtained in step S1 to obtain a sample for use in the machine; S3, testing the sample obtained in step S2, and calculating the PFAS content; The PFAS are short-chain or ultra-short-chain perfluoroalkyl and polyfluoroalkyl substances; The sample is a sample in a surface water-groundwater interaction system; The extraction is solid phase extraction; The detection method is liquid chromatography-mass spectrometry technology.

2. The detection method according to claim 1, characterized in that: In step S1, the sample is a water sample or a sediment sample; The water body is groundwater or surface water; The sediment is soil or river bottom sediment.

3. The detection method according to claim 2, characterized in that: The sample is a water sample, and the pretreatment of the sample is performed according to the following operations: filtering the water sample, adding a PFAS internal standard, and adjusting the pH value to 6-8; The pore size of the filter membrane used in the filtration is 0.22 μm; The amount of the PFAS internal standard added is: 10 ng of internal standard is added to every 1 L of water sample.

4. The detection method according to claim 3, characterized in that: The sample is a water sample, and the extraction column used in the extraction is an Oasis@WAX extraction column; The sample is a water sample, and the eluent used for the extraction is 0.1% ammonia water-methanol.

5. The detection method according to claim 2, characterized in that: The sample is sediment, and the pretreatment of the sample is performed according to the following operations: homogenizing the sediment sample, adding PFAS internal standard, ultrasonic extraction, centrifugation, taking the supernatant, and concentrating; The homogenization process makes the particle size of the sample ≥100 mesh; The amount of the PFAS internal standard added is: 1 ng of internal standard is added to every 1 g of sediment sample; The conditions of the ultrasonic extraction are: 25°C, 40KHz; The centrifugal conditions are: centrifugation on a shaker at 25°C and 5000 r / min; The concentration conditions are as follows: at 40° C. and under nitrogen protection, the liquid volume is concentrated to 2 mL.

6. The detection method according to claim 5, characterized in that: The extractant used in the ultrasonic extraction is a methanol solution containing 100 mM ammonium acetate.

7. The detection method according to claim 5 or 6, characterized in that: The sample is sediment, and the extraction column used in the extraction is a graphitized carbon solid phase extraction column.

8. The detection method according to any one of claims 5 to 7, characterized in that: The sample is sediment, and the eluent used for the extraction is methanol.

9. The detection method according to any one of claims 1 to 8, characterized in that: In step S3, the detection conditions are as follows: Liquid chromatography conditions: Chromatographic column: ACQUITY UPLC BEH C18 column, 1.7 μm, 2.1 mm × 50 mm; Mobile phase: Phase A is 0.005 mol / L ammonium acetate aqueous solution, and phase B is methanol; Flow rate: 0.3ml / min; Injection volume: 10 μL; Column temperature: 40°C; Elution procedure: Mass spectrometry conditions:

10. The detection method according to any one of claims 1 to 9, characterized in that: The PFAS content is calculated according to the following operation: (1) Establishment of standard curve: dilute the PFAS standard solution with 30 wt % methanol aqueous solution to prepare a series of standard solutions of 0, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, and 200 μg / L, and draw a standard curve; The standard curve is as follows: (2) Substitute the ratio of the peak area of ​​each target substance to be detected in the sample to its corresponding internal standard peak area into the standard curve to obtain the injection mass concentration of each target substance to be detected; then substitute the injection mass concentration into the following formula to calculate the mass concentration of the target substance to be detected in the sample; The calculation formula is as follows: in: ρ—mass concentration of each target substance to be measured in the sample, ng / L; ρ1—injection mass concentration, μg / L; V1—final fixed volume of the sample, ml; V—sampling volume, L.

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