A method for detecting perfluoro- and polyfluoroalkyl substances in plasma

Abstract

The application belongs to the field of plasma detection, and particularly relates to a method for detecting perfluoro and polyfluoro alkyl compounds in plasma; comprising the following steps: extracting target perfluoro and polyfluoro alkyl compounds in plasma by ion pair extraction method; mixing plasma with buffer solution, adding tetrabutylammonium hydrogen sulfate solution and mixing uniformly, then adding isotopically labeled mixed solution as an internal standard, subsequently adding methyl tert-butyl ether, vortexing and shaking, then centrifuging and aspirating supernatant, repeating extraction, combining supernatant, blowing dry, and then redissolving with methanol solution to obtain a sample to be detected; detecting the sample to be detected by liquid chromatography tandem quadrupole time-of-flight high-resolution mass spectrometry; and analyzing data to obtain the type and concentration of target perfluoro and polyfluoro alkyl compounds. The method has the advantages of simple sample processing, short detection time, high resolution, strong sensitivity and the like, and can efficiently and accurately quantitatively analyze the concentration of trace PFASs in plasma.

Description

Technical Field

[0001] This invention belongs to the field of plasma detection, specifically relating to a method for detecting perfluorinated and polyfluoroalkyl compounds in plasma. Background Technology

[0002] Per- and polyfluoroalkyl substances (PFASs) are a class of persistent, bioaccumulative, and potentially toxic organic compounds widely used in industrial and consumer products, such as non-stick cookware coatings, waterproof and stain-resistant fabrics, and food packaging materials. Due to their strong chemical stability and resistance to degradation, PFASs can persist in the environment for extended periods and accumulate in organisms through biomagnification in the food chain. In recent years, the environmental pollution caused by PFASs has attracted widespread global attention, and their association with various health problems has been gradually revealed, including liver toxicity, altered immune function, thyroid dysfunction, and cancer. Therefore, monitoring PFASs in biological matrices is of great significance for assessing the risk of adverse health effects and preventing disease.

[0003] PFASs have long biological half-lives and relatively stable concentrations in plasma, reflecting long-term exposure. Therefore, regular collection and accurate detection of PFAS exposure levels in plasma samples are of significant value for long-term monitoring and trend analysis. However, due to the physical and chemical properties of PFASs, they often exist at trace levels in various environments and biological matrices, further increasing the complexity of detection and analysis. Traditional triple quadrupole mass spectrometry (TQMS) detection methods, while providing certain sensitivity and accuracy, often suffer from cumbersome sample processing, long detection times, and insufficient resolution when dealing with complex biological samples (such as plasma). Therefore, developing simpler, more sensitive, and accurate plasma PFAS detection methods is crucial for assessing human exposure levels and studying the health risks of PFASs. The development of high-resolution mass spectrometry (HMS) technology has provided diverse possibilities for identifying PFAS exposure. UHPLC-QTOF-MS, as an emerging detection and analysis technique, combines the high separation efficiency of ultra-high performance liquid chromatography (UHPLC) with the high sensitivity and high resolution of quadrupole time-of-flight mass spectrometry (QTOF-MS), effectively overcoming the limitations of traditional methods. This invention develops a quantitative detection technology based on UHPLC-Q-TOF-MS for the trace detection of PFAS exposure levels in plasma samples (complex matrices). This technology can efficiently and accurately quantify the concentration of various PFASs in plasma, providing a new solution for environmental monitoring, toxicological research, and human exposure assessment of PFASs. Summary of the Invention

[0004] The technical problem this invention aims to solve is to address the shortcomings of existing technologies by providing an analytical method for detecting the concentrations of 21 perfluorinated and polyfluoroalkyl substances (PFASs) in plasma using ultra-high performance liquid chromatography-quadrupole time-of-flight high-resolution mass spectrometry (UHPLC-Q-TOF-MS). This method combines ion-pair extraction sample pretreatment, chromatography-mass spectrometry detection, and multiple isotope internal standard quantitative analysis techniques, achieving high-throughput detection of multiple PFASs in complex matrices (such as plasma). This method offers advantages such as simple sample processing, short detection time, high resolution, and high sensitivity, enabling efficient and accurate quantitative analysis of trace PFAS concentrations in plasma. It provides reliable technical support and innovative solutions for PFAS environmental monitoring, toxicology research, and human exposure risk assessment.

[0005] To address the aforementioned technical problems, this invention discloses a method for detecting perfluorinated and polyfluoroalkyl compounds in plasma, comprising the following steps:

[0006] S1. Target perfluorinated and polyfluoroalkyl compounds in plasma were extracted using ion-pair extraction: plasma was mixed with buffer solution, tetrabutylammonium bisulfate solution was added and mixed well, then isotope-labeled mixed solution was added as an internal standard, followed by the addition of methyl tert-butyl ether. After vortexing and centrifugation, the supernatant was collected. The extraction was repeated, the supernatants were combined, dried and reconstituted with methanol solution to obtain the sample to be tested.

[0007] S2. The sample to be tested was detected by liquid chromatography-tandem quadrupole time-of-flight high-resolution mass spectrometry;

[0008] S3. Analyze the data to obtain the types and concentrations of the target perfluorinated and polyfluoroalkyl compounds.

[0009] The perfluorinated and polyfluoroalkyl compounds include any one or more of the following: perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorobutanesulfonic acid, perfluoropentanesulfonic acid, perfluorohexanesulfonic acid, perfluorooctanesulfonic acid, perfluorononanesulfonic acid, perfluorodecanesulfonic acid, hexafluoropropylene oxide dimer carboxylic acid, dodecylfluoro-3H-4,8-dioxanonanoic acid, 6:2 chlorinated polyfluoroalkyl ether sulfonic acid, and 8:2 chlorinated polyfluoroalkyl ether sulfonic acid.

[0010] In S1, the volume ratio of plasma to buffer solution is 1:10; the volume ratio of plasma to tetrabutylammonium hydrogen sulfate solution is 1:5; the volume ratio of plasma to isotope-labeled mixed solution is 10:1; and the volume ratio of plasma to methyl tert-butyl ether is 1:20.

[0011] Specifically, the buffer solution is a mixed solution of Na2CO3 and NaHCO3, wherein the concentration of Na2CO3 is 0.25 mol / L and the concentration of NaHCO3 is 0.25 mol / L; the concentration of the tetrabutylammonium hydrogen sulfate solution is 0.50 mol / L; and the concentration of the isotope-labeled mixed solution is 25.0 ng / mL.

[0012] In S1, the volume ratio of the plasma to the methanol solution is 1:1; the concentration of the methanol solution is 70% (v / v).

[0013] In S2, the liquid chromatography uses a C18 column, a mobile phase consisting of mobile phase A and mobile phase B, a flow rate of 0.3 mL / min, and a column temperature of 40 °C.

[0014] Specifically, the mobile phase A is a 10 mM ammonium acetate solution; the mobile phase B is pure acetonitrile.

[0015] Specifically, the liquid chromatography uses gradient elution, and the specific elution procedure is as follows:

[0016] 0～ 80 20 8～ 5 95 10～ 5 95 10.75～ 80 20 14 80 20 .

[0017] In S2, the mass spectrometer has an ion source mode of negative ion electrospray ionization and multiple reaction monitoring mode, an ion source temperature of 500℃, an ion source gas 1 pressure of 50psi, an ion source gas 2 pressure of 50psi, a curtain gas pressure of 35psi, a collision gas pressure of 8psi, an ionization temperature of 500℃, a spray voltage of -4500V, and a scanning range of m / z 100~1000.

[0018] In S3, the analysis includes qualitative analysis and quantitative analysis. Qualitative analysis determines the target peak by identifying the retention time and area of ​​the chromatographic peaks of the parent ion and daughter ion in the test sample, thereby identifying the corresponding perfluorinated and polyfluoroalkyl compounds. The time difference between the retention time of the analyte and the corresponding standard should not exceed 30s. Quantitative analysis uses the ratio of the chromatographic peak area of ​​the daughter ion in the test sample to the chromatographic peak area of ​​the corresponding internal standard to achieve quantitative analysis of perfluorinated and polyfluoroalkyl compounds through the internal standard curve method.

[0019] Beneficial effects:

[0020] This invention provides a method for detecting the concentration of 21 PFASs in plasma based on ultra-high performance liquid chromatography-tandem quadrupole time-of-flight high-resolution mass spectrometry. This method features high sensitivity, high accuracy, high throughput, wide applicability, and simple operation, and can meet the needs for accurate detection of trace PFASs. The method can simultaneously detect multiple traditional and novel PFASs, and also supports both long-chain and short-chain PFASs. It is suitable for rapid detection of large batches of samples and provides reliable technical support for comprehensively assessing human PFASs exposure levels. Attached Figure Description

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0022] Figure 1 The mass spectrometry results for detecting 21 PFAS in this embodiment of the invention are shown in Figure A, where A is the total ion current chromatogram of the plasma sample after pretreatment and loading, and B is the chromatogram of the target PFASs and the corresponding internal standard. Detailed Implementation

[0023] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0024] Example 1:

[0025] A method for detecting perfluorinated and polyfluoroalkyl compounds in plasma, specifically comprising the following steps:

[0026] S1. Sample pretreatment:

[0027] (1) Using ion-pair extraction, plasma samples stored in ultra-low temperature freezers were thawed overnight at 4°C. 200 μL of plasma sample was accurately aspirated into a clean 15 mL centrifuge tube, and 2 mL of a mixed solution of 0.25 mol / L Na2CO3 and 0.25 mol / L NaHCO3 was added as a buffer. 1 mL of 0.50 mol / L tetrabutylammonium bisulfate solution was added to improve the extraction efficiency. 20 μL of 25.0 ng / mL isotope-labeled mixed solution was added as an internal standard. 4 mL of methyl tert-butyl ether was added. The mixture was vortexed at 250 rpm for 10 min to fully extract the target per- and polyfluoroalkyl substances (PFASs). After centrifugation at 4000 rpm for 10 min at 4°C, the supernatant was aspirated. The above extraction steps were repeated, and the supernatants from both extractions were combined into a centrifuge tube.

[0028] (2) Use a nitrogen blower in a fume hood to dry the supernatant (about 8 mL) after extraction and combination at 40°C; adjust the nitrogen flow rate to 2 L / min, and continuously adjust to keep the distance between the nitrogen nozzle and the sample surface at about 1 to 2 cm to ensure that the solvent is completely evaporated.

[0029] (3) After drying, the centrifuge tubes were brought to a final volume with 200 μL of 70% methanol solution, vortexed for 1 min, and allowed to stand at 4°C for 30 min. The tubes were then centrifuged at 4000 rpm for 5 min at 4°C. After centrifugation, the supernatant was collected, filtered through a 0.22 μm filter column, and then centrifuged into an autosampler vial.

[0030] S2. Sample Testing:

[0031] The pretreated samples were analyzed using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS).

[0032] The 21 target substances in plasma include: perfluorobutyric acid (PFBA), perfluorovalerate (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanic acid (PFDoA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), and perfluorobutanesulfonic acid (PFBS). Perfluoropentane sulfonic acid (PFPeS), perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorononane sulfonic acid (PFNS), perfluorodecane sulfonic acid (PFDS), hexafluoropropylene oxide dimer carboxylic acid (HFPO-DA), dodecylfluoro-3H-4,8-dioxanonanoic acid (DONA), 6:2 chlorinated polyfluoroalkyl ether sulfonic acid (6:2Cl-PFESA), 8:2 chlorinated polyfluoroalkyl ether sulfonic acid (8:2Cl-PFESA);

[0033] The internal standard compounds corresponding to the 21 target substances include: perfluorobutyric acid (M4PFBA) labeled with 13C, perfluoropentanoic acid (M5PFPeA) labeled with 13C, perfluorohexanoic acid (M5PFHxA) labeled with 13C, perfluoroheptanoic acid (M4PFHpA) labeled with 13C, perfluorooctanoic acid (M8PFOA) labeled with 13C, perfluorononanoic acid (M9PFNA) labeled with 13C, and other compounds. The 21 PFASs are: perfluorodecanoic acid (M6PFDA), perfluoroundecanoic acid (M7PFUnDA), perfluorododecanoic acid (M2PFDoA), perfluorotetradecanoic acid (M2PFTeDA), perfluorobutanesulfonic acid (M3PFBS), perfluorohexanesulfonic acid (M3PFHxS), and perfluorooctanesulfonic acid (M8PFOS). Table 1 lists the full names, abbreviations, CAS numbers, and corresponding internal indices of these PFASs.

[0034] Table 1. Full names, abbreviations, CAS numbers, and corresponding internal indices of 21 types of PFASs

[0035]

[0036]

[0037] The liquid chromatograph used was an AB Sciex ExionLC. TM AC, the conditions for liquid chromatography were as follows: column: WatersAcquity UPLC BEH C18 (2.1 mm × 100 mm, 1.7 μm); mobile phase: phase A was 10 mM ammonium acetate solution, phase B was pure acetonitrile solution; flow rate: 0.3 mL / min; column temperature: 40 ℃; injection volume: 10 μL; gradient elution program is shown in Table 2.

[0038] Table 2 Gradient elution program

[0039] 0～ 80 20 8～ 5 95 10～ 5 95 10.75～ 80 20 14 80 20

[0040] The mass spectrometer used was an AB Sciex X500R QTOF. The mass spectrometry conditions were as follows: negative ion electrospray ionization and multiple reaction monitoring (MRM) mode. The ion source parameters were set as follows: ion source temperature: 500℃; ion source gas 1: 50psi; ion source gas 2: 50psi; curtain gas: 35psi; collision gas: 8psi; ionization temperature: 500℃; spray voltage (IS): -4500V; scan range: m / z 100~1000. The parent ion, daughter ion, declustering voltage, collision energy and retention time of 21 PFASs are shown in Table 3.

[0041] Table 3. Parent ion, daughter ion, declustering voltage, collision energy, and retention time of 21 PFASs

[0042]

[0043]

[0044] The mass spectrometry results of 21 PFAS detected using the method of this invention are as follows: Figure 1 As shown, where, Figure 1 In the figure, A represents the total ion chromatogram of the plasma sample after pretreatment and loading. Figure 1 In the figure, B represents the chromatographic peaks of the target PFASs and the corresponding internal standard. The total ion chromatogram of a plasma sample was detected under the method conditions provided in this invention (see...). Figure 1 A) and the extracted ion chromatograms of the target PFASs and corresponding internal standards (see A). Figure 1 B) The results show that the peaks of the target PFASs and the internal standard are symmetrical and the response signals are high.

[0045] Method verification:

[0046] Establishment of standard curves: The internal standard curve method was used for relative quantitative analysis. A series of standard solutions of 21 PFASs were prepared, covering their linear ranges (Table 4). Nine concentration gradients were set: 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10, and 25.0 ng / mL. For each concentration gradient, 0.5 ng of the corresponding isotope-labeled internal standard was added. The same pretreatment procedure was used, and analysis was performed under the same chromatographic and mass spectrometric conditions. Each concentration was detected three times, and the average value was taken. The standard curve was plotted using the least squares method, with concentration as the x-axis and the ratio of the peak area of ​​the standard analyte to the peak area of ​​the corresponding internal standard as the y-axis. The results are shown in Table 4.

[0047] Detection and Quantification Limits: The limits of detection (LOD) and quantification (LOQ) are confirmed by the signal-to-noise ratio (SNR) of each PFASs at a concentration gradient of 1 ng / mL (corresponding to the isotopic-labeled internal standard of 0.5 ng) during the standard curve plotting process. The LOD is the lowest concentration of the analyte that can be detected and is defined as three times the SNR; the LOQ is the lowest concentration of the analyte that can be accurately quantified and is defined as ten times the SNR.

[0048] The results are shown in Table 4. The 21 PFASs exhibited good linearity in the range of 0.01–25.0 ng / mL, with correlation coefficients (R0 and R0). 2 The LOD of the 21 PFASs was 0.001–0.039 ng / mL, and the LOQ was 0.003–0.131 ng / mL, indicating that the method of the present invention can meet the clinical requirements for the detection of 21 PFASs compounds in plasma.

[0049] Table 4. Standard curves, limits of detection, and limits of quantitation for 21 PFASs

[0050]

[0051] Qualitative and quantitative analysis of target analytes: Target peaks are determined based on the retention times and areas of the precursor and daughter ion chromatographic peaks of the analyte in the ion scan results of actual samples, thus achieving qualitative analysis of the target analyte. During the analysis, the time difference between the retention times of the analyte and the corresponding standard should not exceed 30 seconds. Relative quantitative analysis of the target analyte is achieved by calculating the ratio of the peak area of ​​the daughter ion in the ion scan results of the actual sample to the peak area of ​​the corresponding internal standard ion, using the internal standard curve method. Concentrations of target analytes below the limit of quantitation (LOQ) are calculated by dividing the LOQ by √2.

[0052] Accuracy and precision analysis: The recovery rates of 21 PFASs were determined using a matrix-spiking method to evaluate the sensitivity and accuracy of the detection method. Blank fetal bovine plasma samples were used to prepare PFASs standard solutions at four concentrations: 0.1 ng / mL, 1.0 ng / mL, 2.0 ng / mL, and 5 ng / mL. Three replicates were set for each concentration, and each sample was analyzed three times. The average difference between the measured concentration and the sample concentration was calculated based on the standard curve. The recovery rate of PFASs was obtained by comparing this average difference with the sample concentration.

[0053] The results are shown in Table 5. The recoveries of the 21 PFASs at four spiking concentrations ranged from 75.8% to 128.5%, and the relative standard deviations ranged from 0.4% to 14.8%, indicating that the method of the present invention has good accuracy and precision.

[0054] Table 5. Recovery rates of 21 PFASs

[0055]

[0056] Example 2:

[0057] 390 plasma samples were collected from patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) (HBV-HCC) at the Affiliated Cancer Hospital of Guangxi Medical University, and 390 plasma samples were collected from patients with chronic hepatitis B (CHB) at the Affiliated Wuming Hospital of Guangxi Medical University, the First People's Hospital of Qinzhou City, and the Workers' Hospital of Liuzhou City. All samples were stored at -80℃ for future use.

[0058] 780 plasma samples were pretreated and analyzed by UHPLC-QTOF-MS according to the detection method provided in Example 1.

[0059] During the testing process, 30 plasma samples were randomly selected to prepare a mixed blood sample as a quality control sample. In the same batch of sample testing, 200 μL of the mixed blood sample was aspirated and processed in parallel according to the method provided in this invention. One quality control sample was set up for every 20 plasma samples tested to examine the precision and accuracy of the batch testing. Simultaneously, one blank sample (70% methanol solution) was set up for every 10 plasma samples tested to assess the background contamination of the instrument.

[0060] The test results of the quality control samples indicated that the detection results of the 21 PFASs were reliable, with relative standard deviations ranging from 2.5% to 10.7%. The test results of the blank samples did not indicate background contamination of the instrument. Table 6 shows the median concentration detection rate of the 21 PFASs in 780 plasma samples. As can be seen from the table, 19 types of PFASs were detected in the 780 plasma samples. Among them, the detection rates of PFBA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFPeS, PFHxS, PFOS, and 6:2Cl-PFESA were all above 90%, indicating that the human body was exposed to a mixture of multiple PFASs.

[0061] Table 6. Median concentration detection rate of 21 PFASs in 780 plasma samples

[0062]

[0063] This invention provides a method for detecting perfluorinated and polyfluoroalkyl compounds in plasma. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for detecting perfluorinated and polyfluoroalkyl compounds in plasma, characterized in that, Includes the following steps: S1. Extraction of target perfluorinated and polyfluoroalkyl compounds from plasma using ion-pair extraction: Mix plasma with buffer solution, add tetrabutylammonium bisulfate solution and mix well, then add isotope-labeled mixed solution as internal standard, then add methyl tert-butyl ether, vortex and centrifuge to collect supernatant, repeat the above extraction steps, combine supernatants, blow dry and redissolve with methanol solution to obtain the sample to be tested. S2. The sample to be tested was detected by liquid chromatography-tandem quadrupole time-of-flight high-resolution mass spectrometry; S3. Analyze the data to obtain the types and concentrations of the target perfluorinated and polyfluoroalkyl compounds; The perfluorinated and polyfluoroalkyl compounds include perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorobutane sulfonic acid, perfluoropentane sulfonic acid, perfluorohexane sulfonic acid, perfluorooctane sulfonic acid, perfluorononane sulfonic acid, perfluorodecane sulfonic acid, hexafluoropropylene oxide dimer carboxylic acid, dodecylfluoro-3H-4,8-dioxanonanoic acid, 6:2 chlorinated polyfluoroalkyl ether sulfonic acid, and 8:2 chlorinated polyfluoroalkyl ether sulfonic acid; The liquid chromatograph used was an AB Sciex ExionLC. TM AC, the conditions for liquid chromatography were as follows: Column: Waters Acquity UPLC BEH C18, 2.1 mm × 100 mm, 1.7 μm; Mobile phase: Phase A was 10 mM ammonium acetate solution, and Phase B was pure acetonitrile solution; Flow rate: 0.3 mL / min; Column temperature: 40 ℃; Injection volume: 10 μL; Gradient elution program is shown in the table below: ； The mass spectrometer used was an AB Sciex X500R QTOF. The mass spectrometry conditions were as follows: negative ion electrospray ionization and multiple reaction monitoring mode were used. The ion source parameters were set as follows: ion source temperature: 500 ℃; ion source gas 1: 50 psi; ion source gas 2: 50 psi; curtain gas: 35 psi; collision gas: 8 psi; ionization temperature: 500 ℃; spray voltage: -4500 V; scan range: m / z 100~1000.

2. The method according to claim 1, characterized in that, In S1, the volume ratio of plasma to buffer solution is 1:10; the volume ratio of plasma to tetrabutylammonium hydrogen sulfate solution is 1:5; the volume ratio of plasma to isotope-labeled mixed solution is 10:1; and the volume ratio of plasma to methyl tert-butyl ether is 1:

20.

3. The method according to claim 2, characterized in that, The buffer solution is a mixed solution of Na2CO3 and NaHCO3, wherein the concentration of Na2CO3 is 0.25 mol / L and the concentration of NaHCO3 is 0.25 mol / L; the concentration of the tetrabutylammonium hydrogen sulfate solution is 0.50 mol / L; and the concentration of the isotope-labeled mixed solution is 25.0 ng / mL.

4. The method according to claim 1, characterized in that, In S1, the volume ratio of the plasma to the methanol solution is 1:1; the concentration of the methanol solution is 70% (v / v).

5. The method according to claim 1, characterized in that, In S3, the analysis includes qualitative analysis and quantitative analysis. Qualitative analysis determines the target peak by identifying the retention time and area of ​​the chromatographic peaks of the precursor ion and the daughter ion in the test sample, thereby identifying the corresponding perfluorinated and polyfluoroalkyl compounds. The time difference between the retention time of the analyte and the corresponding standard should not exceed 30 s. Quantitative analysis uses the ratio of the chromatographic peak area of ​​the daughter ion in the test sample to the chromatographic peak area of ​​the daughter ion of the corresponding internal standard to achieve quantitative analysis of perfluorinated and polyfluoroalkyl compounds through the internal standard curve method.

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