Deep eutectic solvent, preparation method and application

Abstract

The invention discloses a deep eutectic solvent, a preparation method and application, the deep eutectic solvent comprises terpenoids and organic acid, preferably menthol and L-lactic acid in an equal molar ratio, and the deep eutectic solvent can be used for sample pretreatment of perfluoroalkyl acid detection. The deep eutectic solvent is simple in formula and can be rapidly prepared without a precise instrument; the raw materials are natural compounds instead of toxic organic solvents in the traditional treatment method, so that the method is green, safe and biodegradable; the deep eutectic solvent is high in perfluoroalkyl acid extraction efficiency, short in time consumption and convenient for subsequent detection.

Description

Technical Field

[0001] The present invention relates to deep eutectic solvents, and in particular to a deep eutectic solvent, a preparation method and an application thereof. Background Art

[0002] Perfluorinated compounds (PFCs) are widely used in industrial and civilian products due to their extremely strong chemical stability and unique physical properties such as hydrophobicity, oleophobicity and high temperature resistance, including textiles, water repellents, food packaging materials and fire-fighting foams. However, these compounds exhibit significant persistence and bioaccumulation in the environment, and are a type of new organic pollutants, which have been detected in water bodies, soils, sediments and organisms globally, and have received extensive attention in the field of environmental science.

[0003] Studies have shown that perfluorinated acids pose multiple threats to ecosystems and human health. They not only have hepatotoxicity, immunotoxicity and endocrine disrupting effects, but may also increase the risk of certain cancers. Among them, the two most common compounds: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), have the highest detection rates in water environments. The concentration ranges of PFOS and PFOA in surface water and groundwater in general areas are 10 - 100 ng / L, while in groundwater near fluorinated industrial parks, it can even reach 20 - 80 μg / L. In some areas polluted by the use or leakage of foam fire extinguishers, the concentration may be as high as 2000 - 5000 μg / L.

[0004] In the analysis of polluted samples, perfluorinated acids often exist at extremely low concentrations, and the sample matrices are complex and diverse. Therefore, efficient sample pretreatment techniques are the key to achieving accurate determination. Currently, commonly used pretreatment methods include liquid - liquid extraction, solid - phase extraction, solid - phase microextraction and ultrasonic extraction, etc., and the analysis means mainly involve chromatography - mass spectrometry (LC - MS / MS or GC - MS / MS), spectrometry (such as ICP - MS), enzyme - linked immunosorbent assay (ELISA) and electrochemical detection techniques.

[0005] Although there are already various detection methods, due to the lack of unified international standards, the existing technologies still have deficiencies in terms of sensitivity, selectivity and operational simplicity. Especially in the sample pretreatment link, traditional methods usually take a long time and consume a large amount of solvents, which is contrary to the concept of green chemistry. Currently, there is no green and rapid sample pretreatment solution for perfluorinated acids. Summary of the Invention

[0006] Object of the Invention: The object of the present invention is to provide a deep eutectic solvent that can be used for extracting perfluorinated acids and a preparation method thereof; the second object is to provide the application of the deep eutectic solvent in the detection of perfluorinated acids.

[0007] Technical solution: The deep eutectic solvent of the present invention comprises a terpene compound and an organic acid; wherein, the terpene compound is any one of menthol, terpineol, citronellol, limonene, and camphor; the organic acid is any one of L-lactic acid, capric acid, and lauric acid; the molar ratio of the terpene compound to the organic acid is 0.5-3:1.

[0008] The preparation method of the deep eutectic solvent of the present invention is to separately weigh the terpene compound and the organic acid, then mix and stir until a transparent liquid is formed.

[0009] Preferably, the stirring is carried out at 50-60 °C for 0.5-1.5 h.

[0010] The application of the deep eutectic solvent of the present invention in the detection of perfluoroalkyl acids.

[0011] Preferably, the application is the application of extracting perfluoroalkyl acids in the sample pretreatment step.

[0012] Preferably, the steps of the application include:

[0013] (1) Filter the sample;

[0014] (2) Add the deep eutectic solvent described in any one of claims 1-5 to the sample obtained in step 1, mix well and then perform ultrasonic treatment;

[0015] (3) Centrifuge the sample after ultrasonic treatment in step 2 at 4500-5500 rpm for 5-15 min, remove the lower water phase, and obtain a perfluoroalkyl acid extract for subsequent detection.

[0016] Preferably, in step 1, the sample is filtered using a filter membrane with a pore size of 0.22-0.45 μm, and the filter membrane is any one of a polytetrafluoroethylene filter membrane, a polyvinylidene fluoride filter membrane, and a nylon filter membrane.

[0017] Preferably, in step 2, the conditions for ultrasonic treatment are pH 2.0-9.0, power 150-250 w, frequency 30-50 kHz, temperature 25-60 °C, and time 1-10 min.

[0018] Preferably, in step 2, sodium chloride with a final concentration of 0-30 g / mL is added during ultrasonic treatment.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: 1. The deep eutectic solvent has a simple formula and can be quickly prepared without precise instruments; 2. The raw materials are compounds from natural sources, replacing the toxic organic solvents in traditional treatment methods, being green, safe, and biodegradable; 3. It is applicable to the sample pretreatment step in the detection of perfluoroalkyl acids, with high extraction efficiency and short time consumption of perfluoroalkyl acids, facilitating subsequent detection. Description of the Drawings

[0020] Figure 1 It is a mechanism diagram for the extraction of perfluoroalkyl acids (taking perfluorooctanoic acid as an example) by deep eutectic solvents (DES);

[0021] Figure 2 It is a Fourier transform infrared (FT-IR) spectrum diagram of L-lactic acid, menthol and synthetic DES;

[0022] Figure 3 It is a Fourier transform infrared spectrum diagram of synthetic DES and perfluorooctanoic acid (PFOA);

[0023] Figure 4 It is a schematic diagram of the influence of the deep eutectic solvent system on the extraction rate of perfluoroalkyl acids;

[0024] Figure 5 It is a schematic diagram of the influence of the volume of the extractant on the extraction rate of perfluoroalkyl acids;

[0025] Figure 6 It is a schematic diagram of the influence of the extraction time on the extraction rate of perfluoroalkyl acids;

[0026] Figure 7 It is a schematic diagram of the influence of the extraction temperature on the extraction rate of perfluoroalkyl acids;

[0027] Figure 8 It is a schematic diagram of the influence of the extraction pH on the extraction rate of perfluoroalkyl acids;

[0028] Figure 9 It is a schematic diagram of the influence of the sodium chloride concentration during extraction on the extraction rate of perfluoroalkyl acids. Detailed implementation mode

[0029] The technical solution of the present invention will be further described below.

[0030] Example 1: Materials, reagents and methods

[0031] Materials and reagents: Menthol, lauric acid, capric acid, L-lactic acid; Perfluorohexane carboxylic acid (PFHXS), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA); Methanol.

[0032] Ultra - high performance liquid chromatography conditions: Use a C18 liquid chromatography column: Waters AQUITY BEH C18 column (2.1 mm × 100 mm, 1.7 μm); Flow rate: 0.4 mL / min; Mobile phase A is ammonium acetate, B is acetonitrile, gradient elution program: 0 - 0.25 min, 20% B; 0.25 - 4.0 min, 20% B - 90% B; 4.0 - 5.0 min, 90% B; 5.0 - 5.01 min, 90% B - 20% B; 5.01 - 6.0 min, 20% B; Column temperature: 40.0 °C; Injection volume: 5 μL.

[0033] Triple quadrupole tandem mass spectrometry conditions: Ion source: ESI; Ion source temperature: 150 °C; Desolvation gas temperature: 500 °C; Capillary voltage: 3.5 kV; Cone - hole back - purge gas flow rate: 50 L / Hr; Desolvation gas flow rate: 900 L / Hr; Collision gas flow rate: 0.16 mL / Min; Collision gas: Argon; Collision gas pressure: 0.32 Pa; Data acquisition mode: Multiple reaction monitoring (MRM).

[0034] Example 2: Application of deep eutectic solvents in the detection of perfluoroalkyl acids under different conditions

[0035] 1. Influence of different deep eutectic solvent systems on extraction

[0036] (1) As shown in Table 1, prepare different deep eutectic solvent systems. Weigh menthol and capric acid, or lauric acid, or L - lactic acid and then mix them. Use a magnetic stirrer to mix at 50 °C for 1 h to form a transparent liquid. After the transparent liquid is formed, store it overnight at room temperature. Observe that there is no solid precipitation in the liquid to obtain the deep eutectic solvent;

[0037] Table 1 Deep eutectic solvent systems

[0038]

[0039] (2) Weigh a certain mass of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA) and perfluorohexane carboxylic acid (PFHXS), dissolve and dilute them with methanol to prepare a 100 ng / L perfluoroalkyl acid mixed standard solution, and store it refrigerated at 4 °C;

[0040] (3) Add 50 μL of DES - 1, 2, 3, 4, 5, 6 deep eutectic solvents to 10 mL of a 100 ng / L perfluoroalkyl acid mixed standard working solution respectively, and use a vortex mixer to mix for 1 min to make them fully mixed;

[0041] (4) Under the conditions of pH 2.0, temperature 50 °C, ultrasonic power 200 W, and ultrasonic frequency 40 kHz, use a numerical control ultrasonic cleaner for ultrasonic extraction for 10 min;

[0042] (5) Centrifuge the solution after ultrasonic extraction at 5000 rpm for 10 min to separate the organic phase from the aqueous phase. Use a syringe to suck out the aqueous phase, and carefully collect the organic phase into the inner liner tube after standing.

[0043] (6) Dilute the collected organic phase with 150 μL of methanol and analyze it using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system.

[0044] The FT-IR spectra of L-lactic acid, menthol, and the synthesized DES are as Figure 2 shown; the FT-IR spectra of the synthesized DES and perfluorooctanoic acid are as Figure 3 shown. The results of infrared spectral analysis indicate that there is a hydrogen bond between the deep eutectic solvent and perfluoroalkyl acid during the extraction process.

[0045] Meanwhile, from Figure 4 it can be seen that the best deep eutectic solvent system is menthol and L-lactic acid with a molar ratio of 1:1.

[0046] 2. Influence of different volumes of deep eutectic solvents on extraction

[0047] (1) Weigh equimolar amounts of menthol and L-lactic acid and mix them. Use a magnetic stirrer to mix at 50 °C for 1 h to form a transparent liquid. After the transparent liquid is formed, store it overnight at room temperature. Observe that there is no solid precipitation in the liquid to obtain the deep eutectic solvent.

[0048] (2) Weigh a certain mass of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA), and perfluorhexane carboxylic acid (PFHXS), dissolve and dilute them with methanol to prepare a 100 ng / L perfluoroalkyl acid mixed standard solution, and store it refrigerated at 4 °C.

[0049] (3) Add 25, 50, 75, 100, and 150 μL of the deep eutectic solvent to 10 mL of the 100 ng / L perfluoroalkyl acid mixed standard working solution respectively, and use a vortex mixer to mix for 1 min to make them fully mixed.

[0050] (4) Under the conditions of pH 2.0, temperature 50 °C, ultrasonic power 200 W, and ultrasonic frequency 40 kHz, use a numerical control ultrasonic cleaner to perform ultrasonic extraction for 10 min.

[0051] (5) Centrifuge the solution after ultrasonic extraction at 5000 rpm for 10 min to separate the organic phase from the aqueous phase. Use a syringe to suck out the aqueous phase, and carefully collect the organic phase into the inner liner tube after standing.

[0052] (6) The collected organic phase was diluted with 150 μL of methanol and analyzed using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system.

[0053] The results are as Figure 5 shown. When the volume of the deep eutectic solvent increased within the range of 25 - 150 μL, the extraction rate of perfluoroalkyl acids showed a trend of first increasing and then decreasing, and the extraction efficiency was the highest at 50 μL. Therefore, the optimal volume of the deep eutectic solvent was selected as 50 μL.

[0054] 3. Influence of different extraction times on extraction

[0055] (1) Menthol and L-lactic acid in equimolar ratio were weighed and mixed, and then mixed at 50 °C for 1 h using a magnetic stirrer to form a transparent liquid. After the transparent liquid was formed, it was stored overnight at room temperature. After observing that no solid was precipitated from the liquid, the deep eutectic solvent was obtained.

[0056] (2) A certain mass of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA) and perfluorohexane carboxylic acid (PFHXS) were weighed, dissolved and diluted with methanol to prepare a 100 ng / L perfluoroalkyl acid mixed standard solution, which was stored refrigerated at 4 °C.

[0057] (3) 50 μL of the deep eutectic solvent was added to 10 mL of a 100 ng / L perfluoroalkyl acid mixed standard solution, and the mixture was mixed for 1 min using a vortex mixer to ensure thorough mixing.

[0058] (4) Under the conditions of pH 2.0, temperature 50 °C, ultrasonic power 200 W, and ultrasonic frequency 40 kHz, the mixture was ultrasonically extracted for 1, 3, 5, 7, and 10 min respectively using a numerically controlled ultrasonic cleaner.

[0059] (5) The solution after ultrasonic extraction was centrifuged at 5000 rpm for 10 min to separate the organic phase and the aqueous phase. The aqueous phase was aspirated using a syringe, and after standing, the organic phase was carefully collected into the liner tube.

[0060] (6) The collected organic phase was diluted with 150 μL of methanol and analyzed using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system.

[0061] The results are as Figure 6 shown. Within the range of 1 - 10 min of extraction time, the extraction rate of perfluoroalkyl acids showed a gradually increasing trend, and the extraction efficiency was the highest at 10 min. Therefore, the optimal extraction time was selected as 10 min.

[0062] 4. Influence of different extraction temperatures on extraction

[0063] (1) Weigh an equimolar ratio of menthol and L-lactic acid, then mix them. Use a magnetic stirrer to mix at 50 °C for 1 h to form a transparent liquid. After the transparent liquid is formed, store it at room temperature overnight. Observe that no solid precipitates from the liquid to obtain a deep eutectic solvent;

[0064] (2) Weigh a certain mass of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA), and perfluorhexane carboxylic acid (PFHXS). Dissolve and dilute them with methanol to prepare a 100 ng / L perfluoroalkyl acid mixed standard solution, and store it refrigerated at 4 °C;

[0065] (3) Add 50 μL of the deep eutectic solvent to 10 mL of the 100 ng / L perfluoroalkyl acid mixed standard solution. Use a vortex mixer to mix for 1 min to fully mix the two;

[0066] (4) Under the conditions of pH 2.0, temperature 25 or 30 or 40 or 50 or 60 °C, ultrasonic power 200 W, and ultrasonic frequency 40 kHz, use a numerical control ultrasonic cleaner to perform ultrasonic extraction for 10 min respectively;

[0067] (5) Centrifuge the solution after ultrasonic extraction at 5000 rpm for 10 min to separate the organic phase from the aqueous phase. Use a syringe to suck off the aqueous phase, and carefully collect the organic phase into the liner tube after standing;

[0068] (6) Dilute the collected organic phase with 150 μL of methanol, and use an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system for analysis.

[0069] The results are as Figure 7 shown. In the range of extraction temperature from 25 to 60 °C, the extraction rate of perfluoroalkyl acids shows a trend of first increasing and then decreasing, and the extraction efficiency is the highest at 50 °C. Therefore, the optimal extraction temperature is selected as 50 °C.

[0070] 5. Influence of different extraction pH on extraction

[0071] (1) Weigh an equimolar ratio of menthol and L-lactic acid, then mix them. Use a magnetic stirrer to mix at 50 °C for 1 h to form a transparent liquid. After the transparent liquid is formed, store it at room temperature overnight. Observe that no solid precipitates from the liquid to obtain a deep eutectic solvent;

[0072] (2) Weigh a certain mass of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA), and perfluorhexane carboxylic acid (PFHXS). Dissolve and dilute them with methanol to prepare a 100 ng / L perfluoroalkyl acid mixed standard solution, and store it refrigerated at 4 °C;

[0073] (3) Add 50 μL of the deep eutectic solvent to 10 mL of the perfluoroalkyl acid mixed standard solution with a concentration of 100 ng / L, and mix them for 1 min using a vortex mixer to ensure thorough mixing.

[0074] (4) Under the conditions of pH 2.0 or 4.0 or 5.0 or 7.0 or 9.0, a temperature of 50 °C, an ultrasonic power of 200 W, and an ultrasonic frequency of 40 kHz, use a numerical control ultrasonic cleaner to perform ultrasonic extraction for 10 min respectively.

[0075] (5) Centrifuge the solution after ultrasonic extraction at 5000 rpm for 10 min to separate the organic phase from the aqueous phase. Use a syringe to suck off the aqueous phase, and carefully collect the organic phase into the liner tube after standing.

[0076] (6) Dilute the collected organic phase with 150 μL of methanol and analyze it using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system.

[0077] The results are as Figure 8 shown. In the range of extraction pH from 2.0 to 9.0, the extraction rate of perfluoroalkyl acids shows a gradually decreasing trend, and the extraction efficiency is the highest at pH 2.0. Therefore, the optimal extraction pH is selected as 2.0.

[0078] 6. Influence of different salt concentrations during extraction

[0079] (1) Weigh equal molar ratios of menthol and L-lactic acid, mix them, and use a magnetic stirrer to mix at 50 °C for 1 h to form a transparent liquid. After the transparent liquid is formed, store it overnight at room temperature. Observe that no solid precipitates in the liquid to obtain the deep eutectic solvent.

[0080] (2) Weigh a certain mass of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA), and perfluorhexane carboxylic acid (PFHXS), dissolve and dilute them with methanol to prepare a perfluoroalkyl acid mixed standard solution with a concentration of 100 ng / L, and store it at 4 °C for refrigeration.

[0081] (3) Add 50 μL of the deep eutectic solvent to 10 mL of the perfluoroalkyl acid mixed standard solution with a concentration of 100 ng / L, and mix them for 1 min using a vortex mixer to ensure thorough mixing.

[0082] (4) Under the conditions of pH 2.0, a temperature of 50 °C, an ultrasonic power of 200 W, and an ultrasonic frequency of 40 kHz, add 0, 5, 10, 20, 30% (w / v) of sodium chloride respectively, and use a numerical control ultrasonic cleaner to perform ultrasonic extraction for 10 min.

[0083] (5) Centrifuge the solution after ultrasonic extraction at 5000 rpm for 10 min to separate the organic phase from the aqueous phase. Use a syringe to aspirate the aqueous phase, and carefully collect the organic phase into the liner tube after standing still.

[0084] (6) Dilute the collected organic phase with 150 μL of methanol and analyze it using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system.

[0085] The results are as Figure 9 shown. When the sodium chloride added during extraction is in the range of 0 - 30% (w / v), the extraction rate of perfluoroalkyl acids first gradually increases and then decreases. The extraction efficiency is the highest when the sodium chloride concentration is 5% (w / v). Therefore, the optimal sodium chloride concentration is selected as 5% (w / v).

[0086] Example 3: Application of Deep Eutectic Solvent under Optimal Conditions in the Detection of Perfluoroalkyl Acids

[0087] (1) Weigh equimolar amounts of menthol and L-lactic acid and mix them. Use a magnetic stirrer to mix at 50 °C for 1 h to form a transparent liquid. After the transparent liquid is formed, store it overnight at room temperature. Observe that no solid precipitates in the liquid to obtain the deep eutectic solvent.

[0088] (2) Weigh a certain mass of perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoDA), and perfluorhexane carboxylic acid (PFHXS), dissolve and dilute them with methanol to prepare a 1500 ng / L perfluoroalkyl acid mixed standard solution. Filter it through a nylon membrane with a pore size of 0.22 μm and store it in a 4 °C refrigerator for analysis (not exceeding 8 hours before analysis).

[0089] (3) Add 50 μL of the deep eutectic solvent to 10 mL of perfluoroalkyl acid mixed standard solutions with concentrations of 5, 10, 100, 200, 500, 1000, and 1500 ng / L respectively. Use a vortex mixer to mix for 1 min to make them fully mixed.

[0090] (4) Under the conditions of pH 2.0, temperature 50 °C, ultrasonic power 200 W, and ultrasonic frequency 40 kHz, add 5% (w / v) of sodium chloride and use a digital control ultrasonic cleaner for ultrasonic extraction for 10 min.

[0091] (5) Centrifuge the solution after ultrasonic extraction at 5000 rpm for 10 min to separate the organic phase from the aqueous phase. Use a syringe to aspirate the aqueous phase, and carefully collect the organic phase into the liner tube after standing still.

[0092] (6) Dilute the collected organic phase with 150 μL of methanol and analyze it using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system.

[0093] The results of the analytical performance parameters for detecting five perfluoroalkyl acids are shown in Table 2.

[0094] Table 2 Analytical performance parameters for detecting perfluoroalkyl acids

[0095]

[0096]

[0097] In summary, the extraction solvent used in the present invention is a deep eutectic solvent, which replaces toxic organic solvents such as acetone in traditional extraction, reduces environmental pollution during the extraction process, and is green and environmentally friendly; the amount of solvent used is very small, and compared with the traditional extraction method, the amount of solvent used is greatly reduced, avoiding secondary pollution to the environment. Compared with solid-phase extraction, the operation is simpler and the cost is lower.

Claims

1. A deep eutectic solvent, characterized in that: It comprises terpenoid compounds and organic acids; wherein the terpenoid compounds are any one of menthol, terpineol, citronellol, limonene and camphor; the organic acid is any one of L-lactic acid, capric acid and lauric acid; and the molar ratio of the terpenoid compounds to the organic acid is 0.5-3:

1.

2. A method for preparing the deep eutectic solvent according to claim 1, characterized in that: The terpenoid compound and the organic acid are weighed separately, mixed, and stirred until a transparent liquid is formed.

3. The preparation method according to claim 2, characterized in that: The stirring is performed at 50-60° C. for 0.5-1.5 h.

4. Use of the deep eutectic solvent according to claim 1 in the detection of perfluoroalkyl acids.

5. The use according to claim 4, characterized in that: It is used for extracting perfluoroalkyl acids in sample pretreatment.

6. The application according to claim 5, characterized in that the step include: (1) Filter the sample; (2) adding the deep eutectic solvent according to any one of claims 1 to 5 to the sample obtained in step 1, mixing thoroughly and then subjecting to ultrasonic treatment; (3) Centrifuge the sample after ultrasonication in step 2 at 4500-5500 rpm for 5-15 min, remove the lower aqueous phase, and obtain a perfluoroalkyl acid extract for subsequent detection.

7. The use according to claim 6, characterized in that: In step 1, filter the sample using a filter membrane with a pore size of 0.22-0.45 μm.

8. The use according to claim 7, characterized in that: The filter membrane is any one of a polytetrafluoroethylene filter membrane, a polyvinylidene fluoride filter membrane, and a nylon filter membrane.

9. The use of the deep eutectic solvent in the detection of perfluoroalkyl acids according to claim 6, characterized in that: In step 2, the conditions of the ultrasonic treatment are pH 2.0-9.0, power 150-250w, frequency 30-50kHz, temperature 25-60°C, and time 1-10min.

10. The use of the deep eutectic solvent in the detection of perfluoroalkyl acids according to claim 6, characterized in that: In step 2, during the ultrasonic treatment, sodium chloride is added to a final concentration of 0-30 g / mL.

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