A method for detecting perfluoro- and polyfluoroalkane compounds in petroleum-contaminated soil
This method utilizes freeze-drying, sieving, acetonitrile extraction, and high-performance liquid chromatography-high-resolution mass spectrometry to detect perfluorinated and polyfluoroalkane compounds in petroleum-contaminated soil. This approach overcomes the detection difficulties caused by matrix effects and achieves highly sensitive and accurate analysis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Filing Date
- 2026-04-10
- Publication Date
- 2026-07-10
Smart Images
Figure CN122361653A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of analytical chemistry technology, and in particular relates to a method for detecting perfluorinated and polyfluorinated alkane compounds in petroleum-contaminated soil. Background Technology
[0002] Per- and polyfluoroalkyl substances (PFAS) are a large class of organofluorine compounds composed of thousands of synthetic chemicals. Due to their excellent surface activity, chemical stability, and thermal stability, these substances are widely used in oil extraction, and market demand continues to grow. Consequently, the environmental pollution risks they pose and the corresponding needs for detection and remediation also persist. However, the chemical composition of petroleum-related samples (including crude oil, drilling mud, catalytic cracking tail oil, and contaminated soil) is extremely complex. The matrix is rich in hydrocarbons, colloids, asphaltenes, and inorganic salts, easily generating strong matrix effects, posing a significant challenge to the accurate analysis of trace PFAS in these samples. Traditional sample pretreatment and detection methods often fail to effectively separate and enrich the target analytes, leading to problems such as low recovery rates and insufficient detection sensitivity.
[0003] Therefore, how to provide a detection method that can effectively reduce matrix effects and achieve high sensitivity and high accuracy in PFAS determination has become a technical problem that urgently needs to be solved in this field.
[0004] In view of this, the present invention is hereby proposed. Summary of the Invention
[0005] The purpose of this application is to provide a method for detecting perfluorinated and polyfluorinated alkane compounds in petroleum-contaminated soil, in order to solve the above-mentioned problems.
[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: This application provides a method for detecting perfluorinated and polyfluoroalkane compounds in petroleum-contaminated soil, characterized by comprising the following steps: S1: Take an appropriate amount of petroleum-contaminated soil, freeze-dry it, crush it, and sieve it. Preferably, a 200-mesh sieve is used for the sieving process.
[0007] S2: Mix the petroleum-contaminated soil after sieving S1 with diatomaceous earth to obtain a mixed sample, put it into the extraction cell, separate the mixed sample from the bottom of the extraction cell with filter paper, and then perform extraction and collect the extract. Preferably, the extractant is acetonitrile; Furthermore, the extraction conditions are: pressure of 10-11 MPa, temperature of 300-350℃, and extraction time of 300-350 s per extraction. Furthermore, the extraction process is repeated 3-5 times.
[0008] S3: Dry the extract, then redissolve it with methanol, filter, and dilute to obtain the sample to be tested; Preferably, the drying is performed by using a nitrogen blower to dry the extract; Furthermore, the filtration process employs a 0.22μm nylon filter membrane. Furthermore, the dilution was performed using mass spectrometry-grade methanol.
[0009] S4: The sample to be tested was detected using a high-performance liquid chromatography-high-resolution mass spectrometry system, and the scanning mode was electrospray negative ion mode; Preferably, during the detection process, depending on the type of perfluorinated and polyfluoroalkyl compounds to be tested, a mobile phase system containing specific additives and corresponding mass spectrometry ionization parameters are used for target analyte separation and mass spectrometry data acquisition.
[0010] Optionally, for perfluorocarboxylic acids (PFCAs), the mobile phase system comprises: mobile phase A: a methanol solution containing 2 mmol / L ammonium acetate and 2 mmol / L N-methylpiperidine, and mobile phase B: pure water; The mass spectrometry ionization parameters are: electrospray voltage of 3-3.5KV and ion transmission tube temperature of 275-325℃.
[0011] Optionally, for perfluorosulfonic acids (PFSAs) and perfluorophosphonic acids (PFPAs), the mobile phase system includes: mobile phase A is a methanol solution containing 2 mmol / L ammonium acetate and 0.1 mmol / L triethylamine, and mobile phase B is pure water; The mass spectrometry ionization parameters are as follows: electrospray voltage is 3KV, ion transmission tube temperature is set to 250℃, and auxiliary gas temperature is set to 500℃.
[0012] Optionally, for perfluorooctane sulfonamides (PFOSAs), the mobile phase system includes: mobile phase A: a methanol solution containing 2 mmol / L ammonium acetate and 2 mmol / L N-methylpiperidine, and mobile phase B is pure water; The mass spectrometry ionization parameters are as follows: electrospray voltage of 4.5 kV, ion transmission tube temperature of 350 °C, and auxiliary gas temperature of 600 °C.
[0013] More preferably, the flow rate of the mobile phase is 0.2-0.3 mL / min, the column temperature is 40℃, and the injection volume is 2 μL.
[0014] More preferably, the gradient condition in step S4 is: At min 0, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%. At 2.5 min, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%. At 8.0 min, the flow rate was 0.3 mL / min, mobile phase A was 95%, and mobile phase B was 5%. At 8.1 min, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%. At 13 minutes, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%.
[0015] S5: Identify compounds based on the accurate molecular ion mass, retention time, and peak shape of the target analyte in the mass spectrometry data.
[0016] Compared with the prior art, this application has the following beneficial effects: Compared to traditional soil PFAS analysis methods, this application effectively overcomes the strong matrix interference effect caused by the coexistence of petroleum hydrocarbons. On the one hand, it significantly improves the accuracy of target compound identification, greatly reduces the method detection limit, and enables the effective detection of low concentrations of PFAS in such compound contaminated sites. On the other hand, it simplifies the pretreatment and identification process, effectively reduces controllable variables in the experimental process, and significantly improves the stability and reproducibility of the method. Meanwhile, the detection results obtained based on this method can cover key qualitative information such as the specific compound name, molecular structure, and relative molecular mass of the target PFAS. This allows for the clarification of the environmental occurrence characteristics and transformation evolution of PFAS in petroleum hydrocarbon coexistence systems, ultimately revealing the migration and transformation mechanism of PFAS in strongly interfering compound contaminated sites, providing key technical support for pollution risk assessment and remediation of such sites. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 The mass spectrum of the detection results of perfluorocarboxylic acids (PFCAs) in Example 1 is shown. Figure 2 This is a mass spectrum of the detection results of perfluorosulfonic acid (PFSA) substances in Example 1. Detailed Implementation
[0019] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0020] The following description is based on specific embodiments.
[0021] Example 1 This embodiment provides a method for detecting perfluorinated and polyfluoroalkane compounds in petroleum-contaminated soil, specifically including the following steps: 1. Extract PFAS compounds from petroleum-contaminated soil according to the following steps: S1: After pre-freezing the petroleum-contaminated soil sample with liquid nitrogen, it was placed in a vacuum dryer for 48 hours. After drying, it was taken out, ground, and passed through a 200-mesh sieve.
[0022] S2: Weigh 2.5g of soil sample after sieving through S1 and mix it with diatomaceous earth. Fill the mixture into a 22mL rapid solvent extraction cell and separate the mixed sample from the bottom of the extraction cell with filter paper. Use acetonitrile as the extractant and extract for 300s at a pressure of 10MPa and a temperature of 300℃. Repeat the extraction process three times and collect the extract.
[0023] S3: Use a nitrogen blower to dry the extract obtained in S2, add 1 mL of methanol to redissolve it, then filter it through a 0.22 μm nylon filter membrane, and then dilute the filtrate one hundred times with mass spectrometry grade methanol before putting it into a mass spectrometry sample vial to obtain the sample to be tested.
[0024] 2. Preparation of the mobile phase: S4: Select different mobile phase systems based on the classification of the analyte: (1) Preparation of ammonium acetate solution: Take 385.4 mg of ammonium acetate and add it to 500 mL of methanol. After dissolving, a stock solution of 10 mmol / L is obtained. Then, it is diluted to a mixed solution of 2 mmol / L as the mobile phase A for detecting perfluorocarboxylic acids (PFCAs). Mobile phase B is pure water.
[0025] (2) Preparation of ammonium acetate mixed with triethylamine and N-methylpiperidine solution: Take 154.16 mg of ammonium acetate into a 1 L glass bottle, and take triethylamine and N-methylpiperidine into 500 mL glass bottles respectively. Use 2 mmol / L ammonium acetate solution to prepare 10 mmol / L ammonium acetate / triethylamine and ammonium acetate / N-methylpiperidine mixed solution as stock solution. Dilute to 2 mmol / L as needed as mobile phase A for the determination of perfluorooctane sulfonamides (PFOSAs). Mobile phase B is pure water.
[0026] (3) For perfluorosulfonic acid (PFSAs) and perfluorophosphonic acid (PFPAs) substances, a mixed solution of 2 mmol / L ammonium acetate and 0.1 mmol / L triethylamine is added to methanol as mobile phase A, and pure water is used as mobile phase B.
[0027] 3. High-performance liquid chromatography-high-resolution mass spectrometry determination: A Thermo Fisher Scientific Q Exactive Plus mass spectrometer was used; the column was an Accucore Vanquish C18+ column (100 x 2.1 mm, 1.5 μm, Thermo Fisher Scientific); the scanning mode was electrospray ionization, negative ion mode. The column temperature was 40℃, the injection volume was 2 μL, and the gradient conditions are shown in Table 1 below: Table 1 Chromatographic Detection Gradient Conditions Select the appropriate ionization parameters based on the type of compound to be tested and the corresponding mobile phase: (1) For perfluorocarboxylic acids (PFCAs), the electrospray voltage is set at 3.5KV and the ion transfer tube temperature is 325℃.
[0028] (2) For perfluorosulfonic acid (PFSAs) and perfluorophosphonic acid (PFPAs) substances, the electrospray voltage is set to 3KV, the ion transfer tube temperature is 250℃, and the auxiliary gas temperature is 500℃.
[0029] (3) For perfluorooctane sulfonamides (PFOSAs), the electrospray voltage is set to 4.5KV, the ion transfer tube temperature is 350℃, and the auxiliary gas temperature is 600℃.
[0030] S5: Qualitative analysis of PFAS compounds The compound was identified by searching the mass spectrometry data for the accurate molecular ion mass, combined with retention time and peak shape. The identification parameters for perfluorinated compounds are shown in Table 2 below: Table 2. Identification Parameters for Perfluorinated Compounds Test results are as follows Figure 1-2 And as shown in Table 3-4 below, where Figure 1 The mass spectrum shows the detection results of perfluorocarboxylic acids (PFCAs). Figure 2 This is a mass spectrum of the detection results for perfluorosulfonic acid (PFSA) substances.
[0031] Table 3. Results of the recovery rate of perfluorocarboxylic acids (PFCAs) Table 4. Results of the recovery rate of perfluorosulfonic acid (PFSA) derivatives. As can be seen from the mass spectrometry and recovery results obtained in this application, the detection method provided in this application can be effectively adapted to extremely complex composite pollutant matrices such as petroleum-contaminated soil, and can significantly suppress strong background interference caused by petroleum hydrocarbons, thereby achieving accurate qualitative analysis of target PFAS compounds.
[0032] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for detecting perfluorinated and polyfluorinated alkane compounds in petroleum-contaminated soil, characterized in that, Includes the following steps: S1: Take an appropriate amount of petroleum-contaminated soil, freeze-dry it, crush it, and sieve it. S2: Mix the petroleum-contaminated soil after sieving S1 with diatomaceous earth to obtain a mixed sample, put it into the extraction cell, separate the mixed sample from the bottom of the extraction cell with filter paper, and then perform extraction and collect the extract. S3: Dry the extract, then redissolve it with methanol, filter, and dilute to obtain the sample to be tested; S4: The sample to be tested was detected using a high-performance liquid chromatography-high-resolution mass spectrometry system, and the scanning mode was electrospray negative ion mode; S5: Identify compounds based on the accurate molecular ion mass, retention time, and peak shape of the target analyte in the mass spectrometry data.
2. The method according to claim 1, characterized in that, In step S1, a 200-mesh sieve is used for the sieving process.
3. The method according to claim 1, characterized in that, In step S2, the extractant is acetonitrile; The extraction conditions are: pressure of 10-11 MPa, temperature of 300-350℃, and extraction time of 300-350 s per extraction. The extraction process is repeated 3-5 times.
4. The method according to claim 1, characterized in that, In step S3, the drying process involves using a nitrogen blower to dry the extract. The filtration process uses a 0.22μm nylon filter membrane. The dilution was performed using mass spectrometry-grade methanol.
5. The method according to claim 1, characterized in that, In step S4, during the detection process, depending on the type of perfluorinated and polyfluoroalkyl compounds to be tested, a mobile phase system containing specific additives and corresponding mass spectrometry ionization parameters are used to separate the target analytes and acquire mass spectrometry data.
6. The method according to claim 5, characterized in that, In step S4, for perfluorocarboxylic acids, the mobile phase system includes: mobile phase A: a methanol solution containing 2 mmol / L ammonium acetate and 2 mmol / L N-methylpiperidine, and mobile phase B: pure water; The mass spectrometry ionization parameters are: electrospray voltage of 3-3.5KV and ion transmission tube temperature of 275-325℃.
7. The detection method according to claim 5, characterized in that, In step S4, for perfluorosulfonic acid and perfluorophosphonic acid, the mobile phase system includes: mobile phase A is a methanol solution containing 2 mmol / L ammonium acetate and 0.1 mmol / L triethylamine, and mobile phase B is pure water; The mass spectrometry ionization parameters are as follows: electrospray voltage is 3KV, ion transmission tube temperature is set to 250℃, and auxiliary gas temperature is set to 500℃.
8. The detection method according to claim 5, characterized in that, In step S4, for perfluorooctane sulfonamides, the mobile phase system includes: mobile phase A: a methanol solution containing 2 mmol / L ammonium acetate and 2 mmol / L N-methylpiperidine, and mobile phase B is pure water; The mass spectrometry ionization parameters are as follows: electrospray voltage of 4.5 kV, ion transmission tube temperature of 350 °C, and auxiliary gas temperature of 600 °C.
9. The method according to any one of claims 1-8, characterized in that, In step S4, the flow rate of the mobile phase is 0.2-0.3 mL / min, the column temperature is 40℃, and the injection volume is 2 μL.
10. The method according to claim 9, characterized in that, The gradient condition in step S4 is: At min 0, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%. At 2.5 min, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%. At 8.0 min, the flow rate was 0.3 mL / min, mobile phase A was 95%, and mobile phase B was 5%. At 8.1 min, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%. At 13 minutes, the flow rate was 0.3 mL / min, mobile phase A was 10%, and mobile phase B was 90%.