Method for separating and enriching 24 perfluorinated compounds in water environment

Abstract

The invention discloses a method for separating and enriching 24 perfluorinated compounds in a water environment. The method comprises the following steps: collecting a to-be-detected water sample, filtering, and adding an isotope labeled recovery rate indicator to obtain a pretreated water sample; activating a PWAX solid-phase extraction column by using a 0.1% ammonia water methanol solution, methanol and ultrapure water in sequence, and enriching a water sample through the column; leaching the PWAX solid-phase extraction column with a 25 mM ammonium acetate aqueous solution (pH = 4) to remove water-soluble interference impurities; carrying out vacuum freeze drying on the solid-phase extraction column, and eluting with methanol and 0.1% ammonia water methanol solution; and blowing the collected eluent to 200 L under nitrogen flow, adding 1: 1 methanol and aqueous solution into the obtained residue, redissolving to 1.00 mL, filtering with a filter membrane, and putting into a polypropylene sample injection bottle to complete separation and enrichment. The method disclosed by the invention is simple and convenient to operate, can enrich various types of perfluorinated compounds (including carboxylic acids, sulfonic acids, fluorosulfonic acids and the like) in water, and is wide in application range and relatively high in accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of pretreatment for the detection of trace organic pollutants in water environment, and particularly relates to a method for separating and enriching 24 perfluorinated compounds in water environment. Background Art

[0002] Per- and polyfluoroalkyl substances (PFAS) are a class of chemical substances with strong fluorocarbon (C-F) bonds, which are widely used in fields such as waterproofing, anti-fouling, and high-temperature resistance, such as polymerization aids, industrial detergents, fire-fighting foams, technical agents, and raw materials for producing hydrophobic and oleophobic materials. Due to the extremely strong chemical stability and non-degradable fluorocarbon bonds in their molecular structures, these substances are persistent in the environment and can even persist in water bodies, soil, and air for decades. Perfluorinated compounds are released into the environment during production, use, and disposal, especially in water environment, posing potential hazards to the ecosystem and human health. Research shows that long-term exposure to PFAS may pose potential hazards to human health and the ecosystem, mainly including risks such as immune system damage, endocrine disruption, and cancer.

[0003] Currently, many countries and regions around the world have formulated relevant standards for perfluorinated compound pollution and require strict environmental monitoring. The US Environmental Protection Agency (EPA) listed perfluorinated compounds as environmental pollutants of concern many years ago and issued relevant standards for perfluorinated compounds in recent years. For example, in 2022, the US Environmental Protection Agency (EPA) set health advisory levels for four perfluorinated compounds in drinking water: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) (0.004 ng / L and 0.02 ng / L respectively) and their short-chain alternative chemicals GenX (hexafluoropropylene oxide dimer acid (HFPO-DA)) and perfluorobutane sulfonate (PFBS) (10 and 2000 ng / L respectively). In 2021, the "Action Plan for the Prevention and Control of Water Pollution" clearly put forward to strengthen the control of water pollution sources, especially the issue of perfluorinated compound emissions in industrial wastewater and domestic sewage. China's "Hygienic Standard for Drinking Water" (GB5749-2022) has also newly added the control of PFOA and PFOS: PFOA < 80 ng / L, PFOS < 40 ng / L, which was implemented in April 2023.

[0004] Currently, a variety of detection methods for perfluorinated compounds have been developed, including but not limited to gas chromatography - mass spectrometry (GC - MS), liquid chromatography - tandem mass spectrometry (LC - MS / MS), high - performance liquid chromatography (HPLC), fluorescence spectrometry, enzyme - linked immunosorbent assay (ELISA), etc. However, the existing technologies still face problems such as low sensitivity, low specificity, high equipment requirements, and long detection cycles. As an efficient analytical technique, UPLC - MS / MS shows unique advantages in the detection of perfluorinated compounds in water environment. By combining liquid chromatography with mass spectrometry, UPLC - MS / MS can effectively separate and quantitatively detect various perfluorinated compounds in water samples, including short - chain, long - chain and their precursor substances, and can overcome the influence of interfering substances in complex matrices. Compared with other detection methods, UPLC - MS / MS has higher sensitivity and selectivity, and can provide more accurate detection results. Summary of the Invention

[0005] The object of the present invention is to provide a method for separating and enriching 24 perfluorinated compounds in water environment.

[0006] The specific steps are as follows:

[0007] (1) Collect the water sample to be tested, filter it, and add an isotope - labeled recovery indicator to obtain the pretreated water sample.

[0008] (2) Activate the PWAX solid - phase extraction column successively with ammonia - methanol solution with a volume percentage concentration of 0.1%, methanol solution, and ultrapure water, so that the resin in the PWAX solid - phase extraction column is in an activated state. Take the pretreated water sample prepared in step (1) and pass it through the PWAX solid - phase extraction column at a flow rate of 3 - 5 mL / min for enrichment. After enrichment, wash it with 25 mM ammonium acetate aqueous solution (pH = 4) to remove the water - soluble interfering impurities enriched on the PWAX solid - phase extraction column. After freeze - drying to remove the moisture in the PWAX solid - phase extraction column, elute it successively with methanol solution and ammonia - methanol solution with a volume percentage concentration of 0.1%. The flow rate of the eluent is less than or equal to 1.0 mL / min. Slowly blow the obtained eluent to 200 µL under a nitrogen stream. Add the obtained residue to a 1:1 (v:v) methanol: aqueous solution for re - dissolution, thus completing the separation and enrichment of 24 perfluorinated compounds in water environment.

[0009] The perfluorinated compounds are perfluorobutyric acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA), perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perfluorobutane sulfonic acid (PFBS), perfluoropentane sulfonic acid (PFPeS), perfluorohexane sulfonic acid (PFHxS), perfluoroheptane sulfonic acid (PFHpS), perfluorooctane sulfonic acid (PFOS), perfluorononane sulfonic acid (PFNS), perfluorodecane sulfonic acid (PFDS), perfluorooctane sulfonamide (FOSA), N-methyl perfluoro-1-octanesulfonamidoacetic acid (N-MeFOSAA), N-ethyl perfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA), sodium 1H,1H,2H,2H-perfluorohexane sulfonate (4:2 FTS), sodium 1H,1H,2H,2H-perfluorooctane sulfonate (6:2 FTS), sodium 1H,1H,2H,2H-perfluorodecane sulfonate (8:2 FTS).

[0010] In the step (1), filtration is preferably carried out using a 0.45 µm glass fiber filter membrane.

[0011] The isotope-labeled recovery indicator in the step (1) is 13 C 4 -PFBA, 13 C 5 -PFPeA, 1,2,3,4,6- 13 C 5 -PFHxA, 1,2,3,4- 13 C 4 -PFHpA, 13 C 8 -PFOA, 13 C 9 -PFNA, 1,2,3,4,5,6- 13 C 6 -PFDA, 1,2,3,4,5,6,7- 13 C 7 -PFUdA, 1,2- 13 C 2 -PFDoA, 1,2- 13 C 2 -PFTeDA, 2,3,4- 13 C 3 -PFBS, 1,2,3- 13 C 3 -PFHxS, 13 C 8-Mixtures of PFOS.

[0012] The pH value of the ammonium acetate aqueous solution used in step (2) is adjusted with formic acid.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1) The reagents used in the process of treating water samples by this method are of low toxicity, with small usage amounts and are environmentally friendly.

[0015] 2) This method has a relatively high enrichment efficiency for perfluorinated compounds in water samples, and the recovery rate is between 46.25% and 126.70%.

[0016] 3) This method is simple to operate and has strong repeatability. The relative standard deviation (RSD) of the same batch of samples is less than 12.84%, meeting the requirements of pretreatment.

[0017] 4) This method can simultaneously enrich various types of perfluorinated compounds in water bodies (including carboxylic acid types, sulfonic acid types, fluorosulfonic acid types, etc.), has a wide application range, takes a relatively short time for instrument detection, has a low detection limit, high accuracy, and high sample detection efficiency. Description of the Drawings

[0018] Figure 1It is the ion chromatogram of the 24 perfluorinated compound mixed standard solution at 10 μg / L in Example 1 of the present invention. Among them, a is perfluorobutyric acid (PFBA): 3.76 min; b is perfluoropentanoic acid (PFPeA): 4.75 min; c is perfluorobutanesulfonic acid (PFBS): 4.89 min; d is perfluorohexanoic acid (PFHxA): 5.69 min; e is sodium 1H,1H,2H,2H-perfluorohexanesulfonate (4:2 FTS): 5.61 min; f is perfluoropentanesulfonic acid (PFPeS): 5.77 min; g is perfluoroheptanoic acid (PFHpA): 6.52 min; h is perfluorohexanesulfonic acid (PFHxS): 6.53 min; i is perfluorooctanoic acid (PFOA): 7.21 min; j is sodium 1H,1H,2H,2H-perfluorooctanesulfonate (6:2 FTS): 7.21 min; k is perfluoroheptanesulfonic acid (PFHpS): 7.22 min; l is perfluorononanoic acid (PFNA): 7.83 min; m is perfluorooctanesulfonamide (FOSA): 8.73 min; n is perfluorooctanesulfonic acid (PFOS): 7.81 min; o is perfluorodecanoic acid (PFDA): 8.35 min; p is sodium 1H,1H,2H,2H-perfluorodecanesulfonate (8:2 FTS): 8.37 min; q is perfluorononanesulfonic acid (PFNS): 8.34 min; r is perfluoroundecanoic acid (PFUdA): 8.82 min; s is N-methyl perfluoro-1-octanesulfonamidoacetic acid (N-MeFOSAA): 8.62 min; t is N-ethyl perfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA): 8.83 min; u is perfluorodecanesulfonic acid (PFDS): 8.78 min; v is perfluorododecanoic acid (PFDoA): 9.22 min; w is perfluorotetradecanoic acid (PFTeDA): 9.59 min; x is perfluorotetradecanoic acid (PFTeDA): 9.93 min.

[0019] Figure 2 It is the quantitative ion standard curve of perfluorobutyric acid (PFBA) in Example 1 of the present invention.

[0020] Figure 3 It is the quantitative ion standard curve of perfluoropentanoic acid (PFPeA) in Example 1 of the present invention.

[0021] Figure 4 It is the quantitative ion standard curve of perfluorohexanoic acid (PFHxA) in Example 1 of the present invention.

[0022] Figure 5 It is the quantitative ion standard curve of perfluoroheptanoic acid (PFHpA) in Example 1 of the present invention.

[0023] Figure 6This is the quantitative ion standard curve of perfluorooctanoic acid (PFOA) in Example 1 of the present invention.

[0024] Figure 7 This is the quantitative ion standard curve of perfluorononanoic acid (PFNA) in Example 1 of the present invention.

[0025] Figure 8 This is the quantitative ion standard curve of perfluorodecanoic acid (PFDA) in Example 1 of the present invention.

[0026] Figure 9 This is the quantitative ion standard curve of perfluoroundecanoic acid (PFUdA) in Example 1 of the present invention.

[0027] Figure 10 This is the quantitative ion standard curve of perfluorododecanoic acid (PFDoA) in Example 1 of the present invention.

[0028] Figure 11 This is the quantitative ion standard curve of perfluorotridecanoic acid (PFTrDA) in Example 1 of the present invention.

[0029] Figure 12 This is the quantitative ion standard curve of perfluorotetradecanoic acid (PFTeDA) in Example 1 of the present invention.

[0030] Figure 13 This is the quantitative ion standard curve of perfluorobutanesulfonic acid (PFBS) in Example 1 of the present invention.

[0031] Figure 14 This is the quantitative ion standard curve of perfluoropentanesulfonic acid (PFPeS) in Example 1 of the present invention.

[0032] Figure 15 This is the quantitative ion standard curve of perfluorohexanesulfonic acid (PFHxS) in Example 1 of the present invention.

[0033] Figure 16 This is the quantitative ion standard curve of perfluoroheptanesulfonic acid (PFHpS) in Example 1 of the present invention.

[0034] Figure 17 This is the quantitative ion standard curve of perfluorooctanesulfonic acid (PFOS) in Example 1 of the present invention.

[0035] Figure 18 This is the quantitative ion standard curve of perfluorononanesulfonic acid (PFNS) in Example 1 of the present invention.

[0036] Figure 19 This is the quantitative ion standard curve of perfluorodecanesulfonic acid (PFDS) in Example 1 of the present invention.

[0037] Figure 20 This is the quantitative ion standard curve of perfluorooctanesulfonamide (FOSA) in Example 1 of the present invention.

[0038] Figure 21 This is the quantitative ion standard curve of N-methyl perfluoro-1-octanesulfonamidoacetic acid (N-MeFOSAA) in Example 1 of the present invention.

[0039] Figure 22 This is the quantitative ion standard curve of N-ethyl perfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA) in Example 1 of the present invention.

[0040] Figure 23 This is the quantitative ion standard curve of sodium 1H,1H,2H,2H-perfluorohexanesulfonate (4:2FTS) in Example 1 of the present invention.

[0041] Figure 24 This is the quantitative ion standard curve of sodium 1H,1H,2H,2H-perfluorooctanesulfonate (6:2FTS) in Example 1 of the present invention.

[0042] Figure 25 This is the quantitative ion standard curve of sodium 1H,1H,2H,2H-perfluorodecanesulfonate (8:2FTS) in Example 1 of the present invention. Detailed implementation manners

[0043] (1) Collect the water sample to be measured, filter it with a GF / F (Whatman, 0.45 µm) glass fiber filter membrane, and add 2 ng of the isotope-labeled recovery indicator to obtain the pretreated water sample.

[0044] (2) Activate the PWAX (CNW, 150 mg, 3 mL) solid-phase extraction column successively with 4 mL of a 0.1% ammonia-methanol solution by volume, 4 mL of methanol solution, and 4 mL of ultrapure water, so that the polymer material in the PWAX solid-phase extraction column is in an activated state. Take 500 mL of the pretreated water sample prepared in step (1) and pass it through the PWAX solid-phase extraction column at a flow rate of 3 - 5 mL / min for enrichment. After the enrichment is completed, wash the PWAX solid-phase extraction column with 4 mL of a 25 mM ammonium acetate aqueous solution (pH = 4) to remove the water-soluble interfering impurities enriched on the PWAX solid-phase extraction column. Then, freeze-dry the PWAX extraction column under vacuum, and elute it successively with 5 mL of methanol solution and 5 mL of a 0.1% ammonia-methanol solution by volume. The elution rate is 1.0 mL / min. Collect the eluate in a 10 mL conical-bottom polypropylene centrifuge tube, and slowly blow the obtained eluate to 200 µL under a nitrogen stream. Add 800 µL of a 1:1 (v:v) methanol:water solution to the obtained residue for reconstitution, and vortex-mix for about 1 min to complete the separation and enrichment of 24 perfluorinated compounds in the water environment.

[0045] The 24 perfluorinated compounds are perfluorobutyric acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA), perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perfluorobutane sulfonic acid (PFBS), perfluoropentane sulfonic acid (PFPeS), perfluorohexane sulfonic acid (PFHxS), perfluoroheptane sulfonic acid (PFHpS), perfluorooctane sulfonic acid (PFOS), perfluorononane sulfonic acid (PFNS), perfluorodecane sulfonic acid (PFDS), perfluorooctane sulfonamide (FOSA), N-methyl perfluoro-1-octanesulfonamidoacetic acid (N-MeFOSAA), N-ethyl perfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA), sodium 1H,1H,2H,2H-perfluorohexane sulfonate (4:2 FTS), sodium 1H,1H,2H,2H-perfluorooctane sulfonate (6:2 FTS), sodium 1H,1H,2H,2H-perfluorodecane sulfonate (8:2 FTS).

[0046] In order to meet the concentration range of perfluorinated compound residues in the water environment, in this embodiment, an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometer (UPLC-MS / MS) is used to quantify the above 24 perfluorinated compounds, and the calibration curve range is 0.1~100 μg / L.

[0047] Drawing of the standard curve by the internal standard method: Dilute the stock solution with methanol into a series of concentration standard mixtures, transfer them to the injection vial, add the internal standard substances (1,2,3,4- 13 C 4 -PFOA, 1,2,3,4- 13 C 4 -PFOS), and measure them with an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometer (UPLC-MS / MS) under the above conditions. Construct a standard curve with the concentration of the target compound as the abscissa and the ratio of the response value of the target compound to the response value of the internal standard as the ordinate, which is used to measure the amount of the analyte in the sample.

[0048] After the perfluorinated compounds in the water environment of this embodiment are separated and enriched, they are detected with an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometer (UPLC-MS / MS), substituted into the standard curve equation, and finally the concentrations of the 24 perfluorinated compounds in the water sample to be measured are obtained through calculation. The recovery rate is calculated using the following formula: Recovery rate:

[0049] .

[0050] R - Recovery rate, %.

[0051] C 2 - Concentration of perfluorinated compounds in the water sample added with standard solution, μg / L.

[0052] C 1 - Concentration of perfluorinated compounds in the water sample without added standard solution, μg / L.

[0053] C S - Concentration of the added standard solution, μg / L.

[0054] V 2 - Volume of the water sample added with standard solution, L.

[0055] V 1 - Volume of the water sample without added standard solution, L;

[0056] Vs - Volume of the added standard solution, L.

[0057] During the experimental process of this example, plastic vessels without fluorine were used to hold the water samples throughout. During the experimental process, the samples should be protected from direct sunlight. The plastic vessels need to be washed multiple times with organic solvents, tap water, and ultrapure water before use.

[0058] The following describes the method for detecting the concentrations of 24 perfluorinated compounds in the water environment of the present invention in conjunction with the accompanying drawings and examples.

[0059] Example 1:

[0060] (1) Take 500 mL of ultrapure water in a polypropylene sampling bottle. Add 0.05 mL of a 200 μg / L mixed standard working solution of 24 perfluorinated compounds to each bottle of water sample. Filter using a GF / F (Whatman, 0.45 µm) glass fiber filter membrane, and add 2 ng of an isotope-labeled recovery indicator to obtain a pretreated water sample.

[0061] (2) Activate the PWAX (CNW, 150 mg, 3 mL) solid-phase extraction column successively with 4 mL of ammonia methanol solution with a volume percentage concentration of 0.1%, 4 mL of methanol solution, and 4 mL of ultrapure water, so that the polymeric material in the solid-phase extraction column is in an activated state. Take 500 mL of the water sample to pass through the column, and control the flow rate at 3 - 5 mL / min. After enrichment, wash the PWAX solid-phase extraction column with 4 mL of 25 mM ammonium acetate aqueous solution (pH = 4) to remove the water-soluble interfering impurities enriched on the PWAX solid-phase extraction column. Then, subject the PWAX extraction column to vacuum freeze-drying. Finally, elute the solid-phase extraction column successively with 5 mL of methanol solution and 5 mL of ammonia methanol solution with a volume percentage concentration of 0.1%, control the flow rate at 1.0 mL / min, collect the eluate in a 10 mL conical-bottom polypropylene centrifuge tube, slowly blow the eluate to 200 µL under a nitrogen stream, add a 1:1 (v:v) methanol: aqueous solution to dissolve the residue, filter it with a 0.22 µm nylon filter membrane, add an internal standard, and vortex mix for about 1 min for determination.

[0062] (3) Determine the concentrations of 24 perfluorinated compounds using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometer (UPLC-MS / MS). Calculate the recovery rates, and the results are shown in Table 1.

[0063] Figure 1This is the ion current chromatogram of a 24-perfluorinated compound mixed standard solution at 10 μg / L in this example. The elution order and retention times are as follows: perfluorobutyric acid (PFBA): 3.76 min; perfluoropentanoic acid (PFPeA): 4.75 min; perfluorobutane sulfonic acid (PFBS): 4.89 min; perfluorohexanoic acid (PFHxA): 5.69 min; sodium 1H,1H,2H,2H-perfluorohexane sulfonate (4:2 FTS): 5.61 min; perfluoropentane sulfonic acid (PFPeS): 5.77 min; perfluoroheptanoic acid (PFHpA): 6.52 min; perfluorohexane sulfonic acid (PFHxS): 6.53 min; perfluorooctanoic acid (PFOA): 7.21 min; sodium 1H,1H,2H,2H-perfluorooctane sulfonate (6:2 FTS): 7.21 min; perfluoroheptane sulfonic acid (PFHpS): 7.22 min; perfluorononanoic acid (PFNA): 7.83 min; perfluorooctane sulfonamide (FOSA): 8.73 min; perfluorooctane sulfonic acid (PFOS): 7.81 min; perfluorodecanoic acid (PFDA): 8.35 min; sodium 1H,1H,2H,2H-perfluorodecane sulfonate (8:2 FTS): 8.37 min; perfluorononane sulfonic acid (PFNS): 8.34 min; perfluoroundecanoic acid (PFUdA): 8.82 min; N-methyl perfluoro-1-octane sulfonamidoacetic acid (N-MeFOSAA): 8.62 min; N-ethyl perfluoro-1-octane sulfonamidoacetic acid (N-EtFOSAA): 8.83 min; perfluorodecane sulfonic acid (PFDS): 8.78 min; perfluorododecanoic acid (PFDoA): 9.22 min; perfluorotetradecanoic acid (PFTeDA): 9.59 min; perfluorotetradecanoic acid (PFTeDA): 9.93 min.

[0064] Internal standard method standard curve plotting: Dilute the stock solution with methanol solution to a series of concentrations of 24-perfluorinated compound standard mixtures at 0.1 μg / L, 0.5 μg / L, 1 μg / L, 2 μg / L, 5 μg / L, 10 μg / L, 20 μg / L, 50 μg / L, and 100 μg / L. Transfer them to a sample vial, add internal standard substances (1,2,3,4- 13 C 4 -PFOA, 1,2,3,4- 13 C 4 -PFOS), and determine them using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometer (UPLC-MS / MS). Plot the concentration of the target compound on the abscissa and the ratio of the response value of the target compound to the response value of the internal standard on the ordinate to obtain the standard curve.

[0065] Figures 2 to 25Quantitative ion standard curves for 24 perfluorinated compounds.

[0066] Example 2:

[0067] Take 500 mL of river water sample from Yanshan District, Guilin City in a polypropylene sampling bottle, add standard substances to the water sample according to the method in Example 1, and at the same time take 500 mL of water sample without adding standard substances as a blank control.

[0068] Substitute the results of the spiked water sample into the standard curve equation, and finally obtain the concentrations of 24 perfluorinated compounds in the water sample to be measured through calculation. Calculate its recovery rate, and the results are shown in Table 2.

[0069] Example 3:

[0070] Collect 500 mL of river and pond water samples from Lingui District, Guilin City with polypropylene sampling bottles, store them at a temperature below 4°C and transport them back to the laboratory. Pretreat the water samples according to the method in Example 1, then detect them by ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry (UPLC-MS / MS), and finally obtain the concentrations of 24 perfluorinated compounds in the actual water samples through calculation by substituting them into the standard curve equation. Calculate the recovery rate, and the results are shown in Table 3.

[0071] Table 1 Experimental results of recovery rate of spiked ultra-pure water

[0072]

[0073] Continued Table 1 Experimental results of recovery rate of spiked ultra-pure water

[0074]

[0075] Table 2 Results of recovery rate of spiked river water samples from Yanshan District, Guilin City

[0076]

[0077] Continued Table 2 Results of recovery rate of spiked river water samples from Yanshan District, Guilin City

[0078]

[0079] Note: ND means not detected.

[0080] Table 3 Determination results of water samples from Lingui District, Guilin City (ng / L)

[0081]

[0082] Note: ND means not detected.

Claims

1. A method for separating 24 perfluorinated compounds in an enriched water environment, characterized in that: The specific steps are: (1) Collect the water sample to be tested, filter it, add the isotope-labeled recovery indicator, and obtain the pretreated water sample; (2) Activate the PWAX solid phase extraction column with a 0.1% volume percent ammonia methanol solution, a methanol solution and ultrapure water in turn, so that the polymer material in the PWAX solid phase extraction column is in an activated state; take the pretreated water sample obtained in step (1) and pass it through the PWAX solid phase extraction column at a flow rate of 3-5 mL / min for enrichment. After the enrichment is completed, the PWAX solid phase extraction column is eluted with a 25 mM ammonium acetate aqueous solution (pH=4) to remove the water-soluble interfering impurities enriched on the PWAX solid phase extraction column, and then the PWAX extraction column is vacuum freeze-dried, and then eluted with a methanol solution and a 0.1% volume percent ammonia methanol solution in turn, the eluent flow rate is less than or equal to 1.0 mL / min, and the obtained eluent is slowly blown to 200 μL under a nitrogen flow, and the obtained residue is added to 1:1 (v:v) methanol:water solution for re-dissolution, and the filter membrane is placed in a polypropylene injection bottle, so as to complete the separation and enrichment of perfluorinated compounds in the water environment; The perfluorinated compounds are perfluorobutyric acid (PFBA), perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perfluorobutane sulfonic acid (PFBS), perfluoropentane sulfonic acid (PF Perfluorooctane sulfonic acid (PFOS), perfluorononane sulfonic acid (PFNS), perfluorodecane sulfonic acid (PFDS), perfluorooctane sulfonamide (FOSA), N-methyl perfluoro-1-octanesulfonamidoacetic acid (N-MeFOSAA), N-ethyl perfluoro-1-octanesulfonamidoacetic acid (N-EtFOSAA), 1H,1H,2H,2H-sodium perfluorohexane sulfonate (4:2 FTS), 1H,1H,2H,2H-sodium perfluorooctane sulfonate (6:2 FTS), 1H,1H,2H,2H-sodium perfluorodecane sulfonate (8:2 FTS).

2. A method for separating 24 perfluorinated compounds in an enriched water environment as claimed in claim 1, characterized in that: In step (1), a 0.45 µm glass fiber filter is used for filtration.

3. A method for separating 24 perfluorinated compounds in an enriched water environment as claimed in claim 1, characterized in that: The isotope-labeled recovery indicator in step (1) is 13 C4-PFBA, 13 C5-PFPeA, 1,2,3,4,6- 13 C5-PFHxA, 1,2,3,4- 13 C4-PFHpA, 13 C8-PFOA, 13 C9-PFNA, 1,2,3,4,5,6- 13 C6-PFDA, 1,2,3,4,5,6,7- 13 C7-PFUdA, 1,2- 13 C2-PFDoA, 1,2- 13 C2-PFTeDA, 2,3,4- 13 C3-PFBS, 1,2,3- 13 C3-PFHxS, 13 Mixture of C8-PFOS.

4. A method for separating 24 perfluorinated compounds in an enriched water environment as claimed in claim 1, characterized in that: The pH value of the 25 mM ammonium acetate aqueous solution used for activation in step (2) is adjusted with formic acid.

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