A method for detecting fluorinated compounds in crabs

Abstract

The application provides a detection method of fluorine compounds in crabs, comprising the following steps: S1, sample preparation, comprising: removing the shell of the crabs to be detected, crushing and homogenizing the edible part to obtain a sample to be detected; S2, extraction, comprising: extracting the sample to be detected, retaining the organic phase and concentrating to obtain a concentrated solution; then adding 5-15 times water of the concentrated solution to dilute to obtain a liquid to be purified; the solvent of the extraction is an aqueous solution of an organic solvent; S3, purification, comprising: purifying the liquid to be purified by using a solid-phase extraction column to obtain a purified liquid; S4, concentration and constant volume, comprising: concentrating the purified liquid to near dryness, redissolving and filtering to obtain a filtrate; S5, sample detection, comprising: detecting the filtrate by using a liquid chromatograph-mass spectrometer, and adopting a standard curve method to qualitatively and quantitatively analyze the fluorine compounds in the crabs. The application can simultaneously determine the content of 41 kinds of PFAS compounds with different physical and chemical properties in the crabs.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of fluorine compound detection, and in particular to a detection method for fluorine compounds in crabs. BACKGROUND

[0002] Per-and poly-fluoroalkyl substances (PFASs) are a class of typical emerging pollutants in which all or part of hydrogen atoms in organic compounds are replaced by fluorine atoms to form carbon-fluorine (C-F) bonds. The carbon-fluorine (C-F) bond is the strongest covalent bond in organic chemistry, with an energy level of 488 kJ mol-1, which endows PFASs with remarkable stability, making them a class of extremely difficult-to-degrade organic pollutants. However, the hydrophobic fluorocarbon chain and the hydrophilic terminal functional group of PFASs make them useful surfactants and polymers, and suitable for various applications, such as waterproof fabrics, water-based film foams and wire coverings, etc. Therefore, since the last century, PFASs have been widely used in various industrial and consumer chemical products. With the migration of PFASs, a kind of “permanent chemical substance”, in the environment, they are extremely widely distributed in the global environment, and can be detected in surface water, groundwater, activated sludge, air, soil, seawater and all animals and human serum media.

[0003] Crabs are very common foods because of their high nutritional value and delicious taste. However, due to the growth environment of crabs, they are deeply affected by PFASs, a kind of “permanent chemical substance”. The environmental persistence, biological accumulation and long-distance migration of the compound have become an important target for pollutant detection in crabs. However, the differences in physicochemical properties of different PFASs (such as ionic and non-ionic types) result in limitations of traditional methods in terms of wide coverage and sensitive detection. The complex matrix of crabs contains a large amount of proteins, fats, pigments and the like. These substances can seriously interfere with the extraction of PFASs, and compete or bind with the target compounds, resulting in low or greatly fluctuating extraction recovery. Due to the great difference in retention behavior of PFASs with different structures on the chromatographic column, it is difficult to simultaneously detect multiple fluorine compounds in one analysis. If co-eluted, they will interfere with each other and affect the quantitative accuracy, resulting in a very low efficiency of batch detection of crabs. In addition, the existing technology mainly uses LC-MS for detection, and the detection sensitivity of some low-content fluorine-containing compounds, such as perfluorocarboxylic acids, may still be insufficient, which is difficult to meet the detection requirements of trace fluorine-containing compounds. SUMMARY

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present application is to provide a detection method of fluorine compounds in crabs, which is used to solve the problems of low detection efficiency, low sensitivity and difficult accurate quantification of fluorine compounds in crabs in the prior art.

[0005] To achieve the above-mentioned purpose and other related purposes, the present application provides a detection method of fluorine compounds in crabs.

[0006] The present application provides a detection method of fluorine compounds in crabs in the first aspect, which comprises:

[0007] S1, sample preparation, comprising: removing the shell of the crabs to be tested, crushing and homogenizing the edible part to obtain a sample to be tested;

[0008] S2, extraction, comprising: extracting the sample to be tested, retaining the organic phase and concentrating to obtain a concentrated solution; then diluting the concentrated solution with 5-15 times water to obtain a liquid to be purified; the solvent for extraction is an aqueous organic solvent;

[0009] S3, purification, comprising: purifying the liquid to be purified using a solid-phase extraction column to obtain a purified liquid;

[0010] S4, concentration and constant volume, comprising: concentrating the purified liquid to near dryness, and filtering the reconstituted solution to obtain a filtrate;

[0011] S5, sample detection, comprising: detecting the filtrate using a liquid chromatography-mass spectrometry instrument, and using a standard curve method to qualitatively and quantitatively analyze the fluorine compounds in the crabs.

[0012] Preferably, the fluorine compounds include any one or more of perfluoroalkyl carboxylic acid, perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonamide, fluoropolymer sulfonic acid, fluoropolymer alkyl carboxylic acid, perfluoroalkyl ether carboxylic acid, polyfluoroalkyl ether sulfonic acid, and disubstituted polyfluoro phosphate ester.

[0013] Further preferably, the perfluoroalkyl carboxylic acid includes any one or more of perfluoropropionic acid, perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, and perfluorohexadecanoic acid.

[0014] Further preferably, the perfluoroalkyl sulfonic acid includes any one or more of perfluoroethanesulfonic acid, perfluorobutanesulfonic acid, perfluoropentanesulfonic acid, perfluorohexanesulfonic acid, perfluoroheptanesulfonic acid, and perfluorooctanesulfonic acid.

[0015] Further preferably, the perfluoroalkyl sulfonamide includes any one or more of perfluorobutanesulfonamide, perfluorohexanesulfonamide, N-methyl N-methyl perfluorooctanesulfonamide ethanol, N-ethyl perfluorooctanesulfonamide, 2 (N-ethyl perfluorooctanesulfonamido) ethanol, perfluorooctanesulfonamide acetic acid;

[0016] Further preferably, the fluorotelomer sulfonic acid includes any one or more of 6:2 fluorotelomer sulfonic acid, 8:2 fluorotelomer sulfonic acid, 10:2 fluorotelmer sulfonic acid;

[0017] Further preferably, the fluorotelomer alkyl carboxylic acid includes any one or more of 3:3 fluorotelomer carboxylic acid, 7:3 fluorotelmer carboxylic acid, 6:2 fluorotelmer carboxylic acid, 8:2 fluorotelmer carboxylic acid;

[0018] Further preferably, the perfluoroalkyl ether carboxylic acid includes any one or more of 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid, perfluoro-2,5-dimethyl-3,6-dioxanonanoic acid, 2,2,3,3-tetrafluoro-3-(trifluoromethoxy)propanoic acid, perfluoro-4-methoxybutanoic acid, perfluoro-3,6-dioxoheptanoic acid;

[0019] Further preferably, the polyfluoroalkyl ether sulfonic acid includes any one or both of 1,1,2,2-tetrafluoro-2-(perfluoroethoxy)ethanesulfonic acid, 9-chloroperfluoro-3-nonyloxy sulfonic acid;

[0020] Further preferably, the disubstituted polyfluoro phosphate ester includes 8:2 fluorotelmer phosphoric acid diester.

[0021] More preferably, the fluorinated compounds include: perfluoropropanoic acid, perfluorobutanoic acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluoroethanesulfonic acid, perfluorobutanesulfonic acid, perfluoropentanesulfonic acid, perfluorohexanesulfonic acid, perfluoroheptanesulfonic acid, perfluorooctanesulfonic acid, perfluorobutylsulfonamide, perfluorohexanesulfonamide, N-methyl perfluorooctanesulfonamide, N-methyl perfluorooctanesulfonamide ethanol, N-ethyl perfluorooctanesulfonamide, 2 (N-ethyl perfluorooctanesulfonamido) ethanol, perfluorooctanesulfonamide acetic acid, 6:2 fluoroterpolymer sulfonic acid, 8:2 fluoroterpolymer sulfonic acid, 10:2 fluoroterpolymer sulfonic acid, 3:3 fluoroterpolymer carboxylic acid, 7:3 fluoroterpolymer carboxylic acid, 6:2 fluoroterpolymer carboxylic acid, 8:2 fluoroterpolymer carboxylic acid, 2,3,3,3-tetrafluoro-2- (heptafluoropropoxy) propanoic acid, perfluoro-2,5-dimethyl-3,6-dioxanonanoic acid, 2,2,3,3-tetrafluoro-3- (trifluoromethoxy) propanoic acid, perfluoro-4-methoxybutanoic acid, perfluoro-3,6-dioxoheptanoic acid, 1,1,2,2-tetrafluoro-2- (perfluoroethoxy) ethanesulfonic acid, 9-chloroperfluoro-3-nonyloxy sulfonic acid, and 8:2 fluoroterpolymer phosphoric acid diester.

[0022] Preferably, the crushing machine is used for crushing and homogenizing the crab powder in step S1.

[0023] Preferably, in step S2, the amount of water added is 1-10 mL based on 1 g of the sample to be detected.

[0024] Further preferably, in step S2, the amount of water added is 1-3 mL based on 1 g of the sample to be detected; including but not limited to 1 mL, 1.5 mL, 2 mL, 2.5 mL or 3 mL.

[0025] Preferably, in step S2, salt is further added to the water and organic solvent after extraction to make the two phases separate; the amount of salt added is 0.5-2.1 g based on 1 mL of water; for example, it can be 0.5 g-0.6 g, 0.6 g-0.8 g, 0.8 g-1.0 g, 1.0 g-1.2 g, 1.2 g-1.4 g, 1.4 g-1.6 g, 1.6 g-1.8 g, 1.8 g-2 g.

[0026] Further preferably, the salt is sodium chloride.

[0027] Preferably, in step S2, the volume ratio of water to organic solvent is 1: (1-5).

[0028] Further preferably, in step S2, the volume ratio of water to organic solvent is 1: (1-3); for example, it can be 1:1, 1:2 or 1:3.

[0029] Preferably, the organic solvent in step S2 is acetonitrile, and the extraction also uses a 30%-40% hydrochloric acid aqueous solution, and the amount of the hydrochloric acid aqueous solution is 0.1%-0.5% of the volume of acetonitrile.

[0030] More preferably, the mass fraction of the hydrochloric acid aqueous solution is 36%-38%.

[0031] Further preferably, in step S2, before adding the salt, the solution of adding the sample, the internal standard, and water is vortex mixed for 1-5 min.

[0032] Further preferably, in step S2, after vortexing, the organic solvent is added, and oscillation is performed for 5-10 min.

[0033] Further preferably, in step S2, after oscillation, the salt is added, and shaking is performed for 5-10 min.

[0034] Further preferably, in step S2, after shaking, centrifugation is performed at 5000-10000 r / min for 5-10 min to separate the water and the organic solvent.

[0035] Further preferably, in step S2, before extraction, the internal standard is added to the sample to be detected, and the amount of the internal standard added is 2-20 ng based on 1 g of the sample to be detected; for example, it can be 2 ng, 5 ng, 10 ng, 15 ng, or 20 ng.

[0036] Further preferably, the internal standard includes any one or more of perfluorobutyric acid-C4 (M4PFBA), perfluorohexanoic acid-C5 (M5PFHxA), perfluorooctanoic acid-C8 (M8PFOA), perfluorododecanoic acid-C12 (MPFDoDA), perfluorooctane sulfonic acid-C8 (M8PFOS), 8:2 fluorotelomer sulfonic acid-C2 (M2-8:2FTS), 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid-C3 (M3HFPO-DA). 13 13 13 13 13 13 13

[0037] Preferably, in step S2, the volume of the liquid to be purified is 5-15 mL; for example, it can be 5 mL, 8 mL, 10 mL, 12 mL, or 15 mL.

[0038] Preferably, in step S3, the solid-phase extraction column is a WAX and HLB mixed column, and the mass ratio of WAX to HLB is 1:(0.5-2); for example, it can be 1:0.5, 1:1, 1:1.5, or 1:2.​​​​​​​

[0039] The WAX is a weak anion exchange filler, which is a weak anion exchange chromatographic filler with polyvinyl pyrrolidone as a matrix and a primary / secondary amine bonded in the structure.

[0040] The HLB is a hydrophilic-lipophilic balance filler, which is a filler with pyrrolidone groups bonded by polystyrene / divinyl benzene, and has both hydrophilic and lipophilic groups on the surface.

[0041] Preferably, the mass of the stationary phase of the solid phase extraction column is 100-200 mg.

[0042] Further preferably, the mass of the stationary phase of the solid phase extraction column is 120-170 mg; for example, it can be 120 mg, 130 mg, 140 mg, 150 mg, 160 mg or 170 mg.

[0043] Preferably, the volume of the solid phase extraction column is 5-10 mL; for example, it can be 5 mL, 6 mL, 7 mL, 8 mL, 9 mL or 10 mL.

[0044] More preferably, the volume of the solid phase extraction column is 5-7 mL.

[0045] Preferably, the ratio of the mass of the stationary phase to the volume of the liquid to be purified passing through the column is 6 mg:(5-15) mL.

[0046] Preferably, in step S3, the purification comprises, in sequence, activation of the solid phase extraction column, sample loading, elution and elution.

[0047] Further preferably, the activation is performed in sequence using 0.05%-0.5% by volume of aqueous ammonia methanol, methanol and water.

[0048] The percentage is the volume percentage of aqueous ammonia in the aqueous ammonia methanol solution.

[0049] Further preferably, the volume of aqueous ammonia methanol used in the activation is 2-10 mL; for example, it can be 2 mL, 4 mL, 5 mL, 6 mL, 8 mL or 10 mL.

[0050] Further preferably, the volume of methanol used in the activation is 2-10 mL; for example, it can be 2 mL, 4 mL, 5 mL, 6 mL, 8 mL or 10 mL.

[0051] Further preferably, the volume of water used in the activation is 2-10 mL; for example, it can be 2 mL, 4 mL, 5 mL, 6 mL, 8 mL or 10 mL.

[0052] Further preferably, the elution liquid is ammonium acetate with a concentration of 10-50 mmol / L.

[0053] More preferably, the elution liquid is ammonium acetate with a concentration of 20-30 mmol / L; for example, it can be 20 mmol / L, 25 mmol / L or 30 mmol / L.

[0054] Further preferably, the volume of the elution liquid is 2-10 mL; for example, it can be 2 mL, 4 mL, 5 mL, 6 mL, 8 mL or 10 mL. Further preferably, in step S3, the elution is followed by vacuum suction of the solid-phase extraction column for 1-3 min, and then elution.

[0055] Further preferably, the elution is performed by using methanol and 0.05%-0.5% ammonia water methanol in sequence.

[0056] Further preferably, the volume of methanol used in the elution is 1-5 mL; for example, it can be 1 mL, 2 mL, 3 mL, 4 mL or 5 mL.

[0057] Further preferably, the volume of ammonia water methanol used in the elution is 2-10 mL; for example, it can be 2 mL, 4 mL, 5 mL, 6 mL, 8 mL or 10 mL.

[0058] Further preferably, the flow rate of the elution is 1-3 s / drop.

[0059] Preferably, in step S4, the concentration is performed by using nitrogen blowing at 30-50°C.

[0060] Preferably, in step S4, the redissolution is performed by using methanol to redissolve the concentrate.

[0061] Preferably, in step S4, the filtration is performed by using a filter membrane with a pore size of 0.1-0.3 μm.

[0062] Further preferably, the pore size of the filter membrane can be 0.1 μm, 0.2 μm or 0.3 μm.

[0063] Preferably, in step S5, the chromatographic conditions include:

[0064] 1) the chromatographic column is a C18 column;

[0065] 2) the column temperature is 35-45°C;

[0066] 3) the injection volume is 1-5 μL;

[0067] 4) the flow rate is 0.1-0.5 mL / min;

[0068] 5) the mobile phase: A phase: 1-3 mM ammonium acetate aqueous solution, B phase: methanol;

[0069] 6) Elution mode: gradient elution, including: initial solvent composition: 75%~80% of phase A and 20~25% of phase B, gradient change stage: the proportion of phase B is linearly increased to 90~95% at 0~14 min, holding stage: 90~95% of phase B is maintained at 14~16 min, column cleaning stage: the proportion of phase B is linearly reduced to 20~25% at 16 min~16.01 min; column equilibration stage: 20~25% of phase B is maintained at 16.01 min~20 min.

[0070] Preferably, in step S5, the mass spectrometry conditions include:

[0071] 1) electrospray ion source, negative ion mode;

[0072] 2) gas curtain gas pressure 30~40 psi;

[0073] 3) spray voltage -4000~-5000 V;

[0074] 4) atomization temperature 450~550℃;

[0075] 5) atomization gas pressure 45~55 psi;

[0076] 6) auxiliary gas pressure 45~55 psi.

[0077] Preferably, in step S5, the concentration of the standard solution selected in the standard curve establishment is 0.005~100 μg / L.

[0078] Preferably, in step S5, the standard curve establishment also includes adding an internal standard, and the amount of the internal standard added is 5~15 ng.

[0079] The second aspect of the present application provides a use of the above method for simultaneously detecting 41 fluorine compounds in crabs.

[0080] It should be noted that the qualified recovery rate in the present application is 60%~140%, and the recovery rate beyond this range cannot correctly reflect the actual content of the test target, so the substance with the recovery rate beyond the range of 60%~140% cannot be quantitatively detected.

[0081] As described above, the method for detecting fluorine compounds in crabs has the following beneficial effects:

[0082] The application adopts liquid-liquid extraction combined with solid phase extraction method to realize effective purification, purification and enrichment of PFASs in crabs, and further combines UPLC-MS / MS to quantitatively detect the purified and enriched substances; the recovery rate of 41 kinds of PFASs in the crab matrix is 60%~140% by using the detection method, the RSD is 0.7%~13.9%, the LOD detection limit of the method in the crab matrix is 0.0011~0.1591 μg / kg; the LOQ quantitative limit is 0.0036~0.5302 μg / kg, and the standard curve correlation coefficient is above 0.999. The application can simultaneously determine the content of at least 41 kinds of PFAS compounds with different physical and chemical properties in crabs, improve the detection efficiency of batch samples, and has the advantages of short time efficiency, high sensitivity, good accuracy and strong stability. BRIEF DESCRIPTION OF DRAWINGS

[0083] Figure 1 A detection process schematic diagram when detecting fluorinated compounds in crabs in the application is shown.

[0084] Figure 2 A chromatogram obtained by UPLC-MS / MS detection of target compounds with a concentration of 20 ng / mL by using the chromatographic conditions of Example 1 in the application is shown, wherein each peak represents: 1: PFPrA; 2: PFBA; 3: PFPeA; 4: PFHxA; 5: PFHpA; 6: PFOA; 7: PFNA; 8: PFDA; 9: PFUnDA; 10: PFDoDA; 11: PFTrDA; 12: PFTeDA; 13: PFHxDA; 14: PFODA.

[0085] Figure 3 A chromatogram obtained by UPLC-MS / MS detection of target compounds with a concentration of 20 ng / mL by using the chromatographic conditions of Example 1 in the application is shown, wherein each peak represents: 1: PFEtS; 2: PFBS; 3: PFPeS; 4: PFHxS; 5: PFHpS; 6: PFOS; 7: PFDS.

[0086] Figure 4 A chromatogram obtained by UPLC-MS / MS detection of target compounds with a concentration of 20 ng / mL by using the chromatographic conditions of Example 1 in the application is shown, wherein each peak represents: 1: PFMPA; 2: PF5OHxA; 3: 3-6-OPFHpA; 4: HPFO-DA; 5: HFPO-TA; 6: ADONA.

[0087] Figure 5A chromatogram obtained by UPLC-MS / MS detection of the target compounds at a concentration of 20 ng / mL using the chromatographic conditions of Example 1 of the present application, wherein each peak represents: 1 : PFEESA; 2: 6:2 Cl-PFESA; 3: FOSAA; 4: 8:2 diPAP.

[0088] Figure 6 A chromatogram obtained by UPLC-MS / MS detection of the target compounds at a concentration of 20 ng / mL using the chromatographic conditions of Example 1 of the present application, wherein each peak represents: 1 : 6:2 FTSA; 2: 8:2 FTSA; 3: 10:2 FTSA.

[0089] Figure 7 A chromatogram obtained by UPLC-MS / MS detection of the target compounds at a concentration of 20 ng / mL using the chromatographic conditions of Example 1 of the present application, wherein each peak represents: 1 : 3:3 FTCA 2: 6:2 FTCA; 3: 7:3 FTCA; 4: 8:2 FTCA.

[0090] Figure 8 A chromatogram obtained by UPLC-MS / MS detection of the target compounds at a concentration of 20 ng / mL using the chromatographic conditions of Example 1 of the present application, wherein each peak represents: 1 : FBSA; 2: FHxSA; 3: FOSA; 4: N-MeFOSA; 5: N-MeFOSE; 6: N-EtFOSA; 7: N-EtFOSE.

[0091] Figure 9 A photograph of a crab sample taken in Example 1 of the present application.

[0092] Figure 10 A chromatogram obtained by detection of fluorinated compounds in crab sample 1 using the detection method of Example 1 of the present application.

[0093] Figure 11 A chromatogram obtained by detection of fluorinated compounds in crab sample 2 using the detection method of Example 1 of the present application. DETAILED DESCRIPTION

[0094] The present application is herein described, by way of example only, with reference to certain embodiments thereof. It is to be understood that the application is not limited in its application to the details set forth in the following description or exemplified by the Examples. The application is capable of other embodiments and of being practiced or carried out in various ways. Variations of the application are possible as would be understood by one of ordinary skill in the art. Examples of changes, omissions, additions and modifications can be made to the application without departing from the spirit of the disclosure.

[0095] It should be understood that the process equipment or device not specifically mentioned in the following examples is the conventional equipment or device in the art.

[0096] Furthermore, it should be understood that the combination of one or more method steps mentioned in the present application does not exclude that other method steps can exist before and after the mentioned combination of steps or that other method steps can be inserted between the explicitly mentioned steps, unless otherwise specified; it should also be understood that the combination of one or more devices / apparatuses mentioned in the present application does not exclude that other devices / apparatuses can exist before and after the mentioned combination of devices / apparatuses or that other devices / apparatuses can be inserted between the explicitly mentioned two devices / apparatuses. Moreover, unless otherwise specified, the numbering of the method steps is only a convenient tool to identify the method steps and is not intended to limit the arrangement of the method steps or to define the scope of the present application, and the change or adjustment of the relative relationship thereof, without substantial change in technical content, is also considered to be within the scope of the present application.

[0097] Before further describing the specific embodiments of the present application, it should be understood that the scope of protection of the present application is not limited to the following specific embodiments; it should also be understood that the terms used in the embodiments of the present application are for the purpose of describing the specific embodiments and are not intended to limit the scope of protection of the present application.

[0098] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified by the present application, both endpoints of each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as generally understood by those skilled in the art. In addition to the specific methods, equipment, materials used in the embodiments, any method, equipment and material of the prior art similar or equivalent to the methods, equipment and materials described in the embodiments of the present application can also be used to implement the present application according to the mastery of the prior art by those skilled in the art and the description of the present application.

[0099] The information of the instruments and equipment used in the embodiments of the present application is as follows:

[0100] Sciex Qtrap 4500 liquid chromatograph-mass spectrometer (AB SCIEX Company, USA), AL104 electronic analytical balance (Mettler Toledo Technology), Synerg® UV ultrapure water machine (Milipore Company, USA), CT14RD desktop high-speed refrigerated centrifuge (Shanghai Tianmei Scientific Instrument Co., Ltd., China), IKA® VIRTEX 3 vortex mixer (IKA Company, Germany), HX-12D solid phase extraction device (Hengxin Century Technology, Wuhan, China), KQ-700VDV dual-frequency digital ultrasonic cleaner (Kunshan Ultrasonic Instrument Co., Ltd., China), 2695 type high-performance liquid chromatograph (ultraviolet detector) (Waters Company, USA).

[0101] The reagents and standards used in the embodiments of this invention are as follows:

[0102] Methanol, acetonitrile (chromatographic grade, Shanghai Xingke High Purity Solvent Co., Ltd.); perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, perfluorohexadecanoic acid, perfluorooctadecanoic acid, perfluoroethanesulfonic acid, perfluoropentanesulfonic acid, perfluoroheptanesulfonic acid, perfluorodecanesulfonic acid, 1,1,2,2-tetrafluoro-2-(perfluoroethoxy)ethanesulfonic acid, 9-chloroperfluoro-3-nonoxysulfonic acid, perfluorobutylsulfonamide, perfluorooctanesulfonamide acetic acid, 6:2 fluoropolymer sulfonic acid, 8:2 fluoropolymer sulfonic acid, 10:2 fluoropolymer sulfonic acid, 3:3 fluoropolymer carboxylic acid, 7:3 Fluoropolymer carboxylic acid, 6:2 fluoropolymer carboxylic acid, 8:2 fluoropolymer carboxylic acid, 4,8-dioxa-3H-perfluorononanoic acid, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propionic acid, perfluoro-2,5-dimethyl-3,6-dioxanonanoic acid, 2,2,3,3-tetrafluoro-3-(trifluoromethoxy)propionic acid, perfluoro-4-methoxybutyric acid, perfluoro-3,6-dioxoheptanoic acid (purity greater than 98%, Alta Technology Co., Ltd. official website); perfluorooctane sulfonic acid, perfluorooctanoic acid, perfluorobutane sulfonic acid, perfluorovalerate, perfluorohexanoic acid, perfluoropropionic acid, perfluoroheptanoic acid, perfluorohexane sulfonic acid, N-methylperfluorooctane sulfonamide, 2-(N-ethylperfluorooctane sulfonamido)ethanol, trifluoroacetic acid, perfluorohexane sulfonamide, 8:2 Fluoropolymer phosphate diester, perfluorobutyric acid, N-ethylperfluorooctane sulfonamide, N-methylperfluorooctane sulfonamide ethanol (purity >80%, Anpu Cloud Laboratory Supplies Co., Ltd.); perfluorooctane sulfonamide, trifluoromethanesulfonic acid (purity >90%, Manhag Biotechnology Co., Ltd.). WAX packing material (Ontwsep™ WAX, Wendu Chromatography Technology Co., Ltd.); HLB packing material (Ontwsep™ HLB, Wendu Chromatography Technology Co., Ltd.); WAX and HLB mixed solid phase extraction column (150mg / 6mL, Wendu Chromatography Technology Co., Ltd.); Column: Excsep™ SiO2@PFP-C18 column (2.1×100 mm, 1.8 μm, Wendu Chromatography Technology Co., Ltd.).

[0103] Figure 1The detection process schematic diagram for detecting fluorine compounds in crabs in the application is shown, and the detection process includes: step S1, crushing and homogenizing the edible part of the crabs to be detected to obtain a sample to be detected; step S2, extracting the sample to be detected, retaining the organic phase and concentrating to obtain a concentrated solution; then adding 5-15 times water to dilute the concentrated solution to obtain a liquid to be purified; the solvent for extraction is an aqueous organic solvent; step S3, purifying the liquid to be purified using a solid-phase extraction column to obtain a purified liquid; step S4, concentrating the purified liquid to near dryness, redissolving and filtering to obtain a filtrate; step S5, detecting the filtrate using a liquid chromatography-mass spectrometry instrument, and using a standard curve method to qualitatively and quantitatively analyze the fluorine compounds in crabs.

[0104] In step S1, the edible part of the crabs in the application is prepared by removing the shell and inedible part of the crabs, and the data of the edible part can be directly used to evaluate food safety.

[0105] In step S2, adding acid to the extraction solution can purify the fluorine compounds in the organic phase, which is beneficial to improve the recovery rate. Too high or too low amount of acid added will affect the recovery rate.

[0106] After water and organic solvent extraction, salt is added to realize layering to facilitate phase separation.

[0107] After extraction, the water and organic phase are separated, and then water is further added to form a liquid to be purified. The addition of water allows the fluorine compounds to be well separated from the solution and retained in the packing material during S3 purification, and they will not be washed down with the organic solvent.

[0108] In step S3, the solid-phase extraction column used in the application has a specification of (150 mg / 6 mL), which is composed of WAX:HLB with a mass ratio of 1:1. The applicant found that when only one type of packing material is used, the single mechanism of the packing material makes it impossible to retain some types of fluorine compounds in the column, and only a small number of types of fluorine compounds can be separated out. However, after mixing the weak anion exchange packing material and the hydrophilic-lipophilic balance packing material and passing through the column, a stronger retention power is provided, and 41 types of PFAS compounds can be effectively separated out, improving the detection efficiency of batch samples.

[0109] When using a solid-phase extraction column to purify the sample, the steps of activation, sample loading, elution and elution are performed in sequence. During activation, 0.1% ammonia methanol, methanol and water are used in sequence to make the packing material in the column wet and balanced. During sample loading, the sample solution passes through the activated column, so that the target compounds are selectively retained by the stationary phase. During elution, 25 mmol / L ammonium acetate can be used to remove weakly adsorbed impurities. During elution, methanol and ammoniated methanol can be used to effectively separate and elute fluorine compounds with different polarities.

[0110] In the present application, the target compounds are the 45 PFASs compounds. The 45 PFASs compounds include perfluoroalkyl carboxylic acids PFCAs, perfluoroalkyl sulfonic acids PFSAs, perfluoroalkyl sulfonamides FASAs, fluorotelomer sulfonic acids FTSAs, fluorotelomer alkyl carboxylic acids FTCAs, perfluoroalkyl ether carboxylic acids PFECAs, disubstituted polyfluoro phosphate esters diPAPs. The names and CAS numbers of the 45 compounds are as follows: perfluoroalkyl carboxylic acids PFCAs include: perfluoropropanoic acid PFPrA CAS No. 422-64-0; perfluorobutanoic acid PFBA CAS No. 375-22-4; perfluoropentanoic acid PFPeA CAS No. 2706-90-3; perfluorohexanoic acid PFHxA CAS No. 307-24-4 307-24-4; perfluoroheptanoic acid PFHpA CAS No. 375-85-9; perfluorooctanoic acid PFOA CAS No. 335-67-1; perfluorononanoic acid PFNA CAS No. 375-95-1; perfluorodecanoic acid PFDA CAS No. 335-76-2; perfluoroundecanoic acid PFUnDA CAS No. 2058-94-8; perfluorododecanoic acid PFDoDA CAS No. 307-55-1; perfluorotridecanoic acid PFTrDA CAS No. 72629-94-8; perfluorotetradecanoic acid PFTeDA CAS No. 376-06-7; perfluorohexadecanoic acid PFHxDA CAS No. 67905-19-5; perfluorooctadecanoic acid PFODA CAS No. 16517-11-6. Perfluoroalkyl sulfonic acids PFSAs include: perfluoroethanesulfonic acid PFEtS CAS No. 354-88-1; perfluorobutanesulfonic acid PFBS CAS No. 375-73-5; perfluoropentanesulfonic acid PFPeS CAS No. 2706-91-4; perfluorohexanesulfonic acid PFHxS CAS No. 355-46-4; perfluoroheptanesulfonic acid PFHpS CAS No. 375-92-8; perfluorooctanesulfonic acid PFOS CAS No. 1763-23-1; perfluorodecanesulfonic acid PFDS CAS No. 335-77-3.Perfluoroalkyl sulfonamides FASAs include: perfluorobutanesulfonamide FBSA CAS number 30334-69-1; perfluorohexanesulfonamide FHxSA CAS number 41997-13-1; perfluorooctanesulfonamide FOSA CAS number 754-91-6; N-methyl perfluorooctanesulfonamide N-MeFOSA CAS number 31506-32-8; N-ethyl perfluorooctanesulfonamide N-EtFOSA CAS number 4151-50-2; 2(N-ethyl perfluorooctanesulfonamido)ethanol N-EtFOSE CAS number 1691-99-2; N-methyl perfluorooctanesulfonamide ethanol N-MeFOSE CAS number 24448-09-7; perfluorooctanesulfonic acid FOSAA CAS number 2806-24-8. Fluorotelomer sulfonic acids FTSAs include: 6:2 fluorotelomer sulfonic acid 6:2 FTSA CAS number 27619-97-2; 8:2 fluorotelomer sulfonic acid 8:2 FTSA CAS number 39108-34-4; 10:2 fluorotelomer sulfonic acid 10:2 FTSA CAS number 120226-60-0. Fluorotelomer alkyl carboxylic acids FTCAs include: 3:3 fluorotelomer carboxylic acid 3:3 FTCA CAS number 356-02-5; 7:3 fluorotelomer carboxylic acid 7:3 FTCA CAS number 812-70-4; 6:2 fluorotelomer carboxylic acid 6:2 FTCA CAS number 53826-12-3; 8:2 fluorotelomer carboxylic acid 8:2 FTCA CAS number 27854-31-5. Perfluoroalkyl ether carboxylic acids PFECAs include: 4.8-dioxa-3H-perfluorononanoic acid ADONA CAS number 919005-14-4; 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid HFPO-DA CAS number 13252-13-6; perfluoro-2,5-dimethyl-3,6-dioxanonanoic acid HFPO-DA CAS number 13252-14-7; 2,2,3,3-tetrafluoro-3-(trifluoromethoxy)propanoic acid PFMPA CAS number 377-73-1; perfluoro-4-methoxybutanoic acid PF5OHxA CAS number 863090-89-5; perfluoro-3,6-dioxepheptanoic acid 3-6-OPFHpA CAS number 151772-58-6. Polyfluoroalkyl ether sulfonic acids PFESAs include: 1,1,2,2-tetrafluoro-2-(perfluoroethoxy)ethanesulfonic acid PFEESA CAS number 113507-82-7; 9-chloroperfluoro-3-nonyloxy sulfonic acid 6:2 Cl-PFESA CAS number 756426-58-1. Disubstituted polyfluoro phosphates diPAPs include 8:2 fluorotelomer phosphate diester 8:2 diPAP CAS number 678-41-1.

[0111] In step S4, the concentration to near dryness is defined as visually observing no liquid flow at the bottom of the container. Before injection into UPLC-MS / MS, the reconstituted methanol solution needs to be filtered to remove small insoluble particles, prevent column clogging, and ensure data quality.

[0112] Example 1

[0113] This embodiment 1 provides a method for detecting 41 PFASs compounds in crabs. The difference between these 41 PFASs compounds and the 45 PFASs compounds mentioned above is that they do not include perfluorooctanoic acid (PFODA, CAS number 16517-11-6); perfluorodecane sulfonic acid (PFDS, CAS number 335-77-3); perfluorooctane sulfonamide (FOSA, CAS number 754-91-6); and 4,8-dioxa-3H-perfluorononanoic acid (ADONA, CAS number 919005-14-4). The specific detection method includes the following steps:

[0114] S1, Sample Preparation

[0115] Take as Figure 9 One crab of the indicated type was used. The shell was removed, and the edible parts were taken. The sample was cut into small pieces, thoroughly pulverized and mixed using a grinder, then sealed. The prepared sample was stored at -18°C or below, protected from light, for later use. All tools used during the process must be cleaned with deionized water to prevent cross-contamination between samples.

[0116] S2, Extraction

[0117] Thaw and homogenize the sample prepared in S1. Weigh 2 g of the sample and place it in a 50 mL polypropylene centrifuge tube. Add 50 μL of internal standard mixed solution (0.2 μg / mL), add 3 mL of water, vortex for 1 min, add 6 mL of acetonitrile and 20 μL of concentrated hydrochloric acid (mass fraction 36%~38%), and shake for 5 min. Add 2 g of sodium chloride, shake again for 5 min, and centrifuge at 8000 r / min for 5 min. Transfer the upper acetonitrile solution to another test tube, purge with nitrogen in a 40℃ water bath until approximately 1 mL remains, and add water to bring the volume to 10 mL. This is the purification solution.

[0118] S3, Enrichment and Purification

[0119] The sample was purified by a solid phase extraction column with WAX:HLB (150 mg / 6 mL) at a mass ratio of 1:1. The solid phase extraction column was activated with 4 mL of 0.1% ammonia methanol, 4 mL of methanol and 4 mL of water in sequence, and kept wet. The sample to be purified was immediately loaded onto the solid phase extraction column after activation. After loading, the solid phase extraction column was rinsed with 4 mL of 25 mmol / L ammonium acetate, and the rinsing solution was discarded. The column was vacuumed for 2 min until it was nearly dry. Then, 2 mL of methanol and 4 mL of 0.1% ammonia methanol solution were used for elution in sequence at a flow rate of 2-3 s / 1 drop. The eluate was collected and concentrated to near dryness at 40°C under nitrogen. 1 mL of methanol was accurately added for dissolution. The solution was filtered through a needle cylinder filter with a pore size of 0.22 μm. The filtrate was used as the test solution for UPLC-MS / MS analysis.

[0120] S4, Preparation of Mixed Standard Working Solution and Drawing of Standard Curve

[0121] A certain amount of perfluoro / polyfluorinated compound mixed standard stock solution and internal standard solution were diluted with methanol to a series of mixed standard working solutions with concentrations of 0.005, 0.01, 0.05, 0.1, 0.5, 1.0, 5.0, 10.0, 50.0, 100.0 μg / L (containing 10 μg / L of internal standard, respectively). The UPLC-MS / MS method was used for determination according to the method established in the present application. The peak area ratio of 45 kinds of PFASs and their corresponding isotopic internal standards was used as the ordinate (y), and the concentration of PFASs was used as the abscissa (x) to draw the standard curve. The internal standard method was used for quantitative analysis. The solute in the perfluoro / polyfluorinated compound mixed standard stock solution was the 45 kinds of PFASs compounds, and the solvent was methanol. The concentrations of the 45 kinds of PFASs compounds in the perfluoro / polyfluorinated compound mixed standard stock solution were consistent. The solvent of the internal standard solution was methanol, and the solute was as shown in Table 2. The concentrations of each solute were consistent.

[0122] S5, UPLC-MS / MS Analysis and Test of the Test Solution

[0123] S5.1, Chromatographic Conditions

[0124] The chromatographic column was Excsep TM SiO2@PFP-C18 column, column temperature 40°C, injection volume 2 μL, flow rate 0.3 mL / min. The mobile phase was 2 mM ammonium acetate aqueous solution (A) and methanol (B) for elution, and the mobile phase gradient was as shown in Table 1.

[0125] Table 1 Mobile phase gradient

[0126]

[0127] S5.2, Mass Spectrometry Conditions

[0128] Electrospray ion source was selected, and negative ion mode was used. Ionization parameters were as follows: gas curtain pressure, 35.0 psi; spray voltage, -4500 V; atomization temperature, 500℃; atomization gas pressure, 50 psi; auxiliary gas pressure, 50 psi. The specific mass spectrum is shown in Table 2.

[0129] Table 2 Mass spectrum parameters of 45 PFASs and corresponding internal standards

[0130]

[0131]

[0132]

[0133] The results of linear equations, correlation coefficients and linear ranges obtained by UPLC-MS / MS method for determining different concentrations of standard solutions under the above chromatographic and mass spectrometric conditions are shown in Table 3. Seven PFASs have good linear relationships in the range of 0.1-100 μg / L, PFDoDA has good linear relationship in the range of 0.05-100 μg / L, 27 PFASs have good linear relationships in the range of 0.01-100 μg / L, and the remaining 10 PFASs have good linear relationships in the range of 0.005-100 μg / L, and their correlation coefficients are greater than or equal to 0.999.

[0134] Table 3 Linear range, regression equation and correlation coefficient of 45 PFASs

[0135]

[0136]

[0137] Figures 2-8 To dissolve the target compound in methanol, a standard solution with a concentration of 20 ng / mL was prepared, and the chromatograms of each standard were obtained by UPLC-MS / MS detection under the above chromatographic conditions.

[0138] Further, the matrix effect (ME), the recovery rate of the added standard, and the detection limit (LOD) and the quantification limit (LOQ) of the target compound in different crabs were detected. Specifically, the standard addition method was used to evaluate the matrix effect of the crab matrix, and the relative response value of the target compound added in the sample matrix and the relative response value of the target compound in the pure solvent were compared; the recovery rate of the added standard was set at two levels of 2.5 μg / kg and 25 μg / kg, and three parallel samples were set at each concentration to verify the accuracy of the method; the LOD value was calculated according to the signal-to-noise ratio S / N=3, and the LOQ value was calculated according to the signal-to-noise ratio S / N=10; the results are shown in Table 4.

[0139] Table 4 Recovery, RSD (n=3), ME, LOD and LOQ of 45 PFASs in crab samples

[0140]

[0141]

[0142] It can be seen from the data in Table 4 that PFTeDA, PFODA, FHxSA, FOSA, N-MeFOSA and N-EtFOSA have strong matrix effects in crabs. In actual quantitative tests, matrix correction curves need to be used to calibrate the quantitative results. When the spiked concentration is 2.5 μg / kg, the recovery rate of FOSA exceeds the qualified recovery rate range. When the spiked concentration is 25 μg / kg, the recovery rates of PFODA, PFDS, FOSA and ADONA exceed the qualified recovery rate range. Therefore, the above 4 PFASs do not meet the basic requirements of quantitative analysis. In the subsequent actual sample test results, the related data is not included in the statistical range. The recovery rates of the remaining 41 PFASs are within the qualified recovery rate range (60%~140%), the RSD is 0.7~13.9%, which can meet the basic requirements of quantitative analysis, the LOD is 0.0011~0.1591 μg / kg, and the LOQ is 0.0036~0.5302 μg / kg.

[0143] Further, the established detection method is applied to the determination of 2 crab samples, wherein crab samples 1~2 are crabs in Figure 9 , and the samples are purchased from a retail market in a city in Zhejiang Province. The quantitative results are shown in Table 5, and the detection chromatogram is shown in Figures 10-11 .

[0144] Table 5 Concentrations (μg / kg) of 41 PFASs in crab samples 1~5 along the coast of Zhejiang

[0145]

[0146]

[0147] Note: ND is not detected, and <LOQ is less than the limit of quantification.

[0148] According to Table 5 and Figures 10-11It can be seen from the results that: in the crab sample 1, 26 kinds of fluorine-containing compounds can be detected, among which the contents of PFBA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, PFTeDA, PFBS, PFPeS, PFOS, FBSA, FOSAA, HFPO-TA, PF5OHxA and 8:2 diPAP exceed the quantitative limit; in the crab sample 2, 26 kinds of fluorine-containing compounds can be detected, among which the contents of PFBA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, PFTeDA, PFBS, PFOS, FBSA, HFPO-DA, HFPO-TA and 8:2 diPAP exceed the quantitative limit.

[0149] In summary, the detection method is suitable for trace detection of perfluoro / polyfluoro compounds in crabs, and provides a feasible processing method for samples with small sample amount. The extraction, purification and enrichment method in the method is simple, the detected fluorine compound types are relatively complete, the time consumption is short, the recovery rate is good, the detection limit and the quantitative limit are relatively low, and monitoring the content of PFASs in crabs has important significance for guaranteeing food safety and public health, evaluating ecological environment risk and tracing pollution source.

[0150] The above description is only a preferred embodiment of the present application, and is not a limitation on the form and essence of the present application. It should be pointed out that, for ordinary skilled persons in the art, some improvements and supplements can be made without departing from the method of the present application, and these improvements and supplements should also be regarded as the protection scope of the present application. For those skilled in the art, some minor changes, modifications and equivalent changes made on the basis of the disclosed technical content without departing from the spirit and scope of the present application are equivalent embodiments of the present application; at the same time, any equivalent changes, modifications and evolution of the above-mentioned embodiments according to the essential technology of the present application are still within the scope of the technical solutions of the present application.

Claims

1. A method for detecting a fluorine compound in a crab, characterized by, The method comprises: S1, sample preparation, comprising: removing the shell of the to-be-tested crab, crushing and homogenizing the edible part to obtain a to-be-tested sample; S2, extraction, comprising: extracting the to-be-tested sample, retaining an organic phase and concentrating to obtain a concentrated liquid; then adding water in an amount of 5-15 times that of the concentrated liquid to dilute to obtain a to-be-purified liquid; the solvent for extraction is an organic solvent aqueous solution, and the organic solvent is acetonitrile; S3, purification, comprising: purifying the to-be-purified liquid using a solid-phase extraction column to obtain a purified liquid; S4, concentration and constant volume, comprising: concentrating the purified liquid to near dryness, redissolving and filtering to obtain a filtrate; S5, sample detection, comprising: detecting the filtrate using a liquid chromatography-mass spectrometry instrument, adopting a standard curve method, and qualitatively and quantitatively analyzing fluorinated compounds in the crab; The fluorinated compounds include perfluoroalkyl carboxylic acids, perfluoroalkyl sulfonic acids, perfluoroalkyl sulfonamides, fluorotelomer sulfonic acids, fluorotelomer alkyl carboxylic acids, perfluoroalkyl ether carboxylic acids, polyfluoroalkyl ether sulfonic acids, and disubstituted polyfluoro phosphates; the perfluoroalkyl carboxylic acids include perfluoropropionic acid, perfluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, perfluorotridecanoic acid, perfluorotetradecanoic acid, and perfluorohexadecanoic acid; the perfluoroalkyl sulfonic acids include perfluoroethanesulfonic acid, perfluorobutanesulfonic acid, perfluoropentanesulfonic acid, perfluorohexanesulfonic acid, perfluoroheptanesulfonic acid, and perfluorooctanesulfonic acid; the perfluoroalkyl sulfonamides include perfluorobutyl sulfonamide, perfluorohexanesulfonamide, N-methyl perfluorooctanesulfonamide, N-methyl perfluorooctanesulfonamide ethanol, N-ethyl perfluorooctanesulfonamide, 2(N-ethyl perfluorooctanesulfonamido) ethanol, and perfluorooctanesulfonamide acetic acid; the fluorotelomer sulfonic acids include 6:2 fluorotelomer sulfonic acid, 8:2 fluorotelomer sulfonic acid, and 10:2 fluorotelomer sulfonic acid; the fluorotelomer alkyl carboxylic acids include 3:3 fluorotelomer carboxylic acid, 7:3 fluorotelomer carboxylic acid, 6:2 fluorotelomer carboxylic acid, and 8:2 fluorotelomer carboxylic acid; the perfluoroalkyl ether carboxylic acids include 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propionic acid, perfluoro-2,5-dimethyl-3,6-dioxanonanoic acid, 2,2,3,3-tetrafluoro-3-(trifluoromethoxy) propionic acid, perfluoro-4-methoxy butyric acid, and perfluoro-3,6-dioxoheptanoic acid; the polyfluoroalkyl ether sulfonic acids include 1,1,2,2-tetrafluoro-2-(perfluoroethoxy) ethanesulfonic acid and 9-chloro perfluoro-3-nonyloxy sulfonic acid; and the disubstituted polyfluoro phosphates include 8:2 fluorotelomer phosphate diester; In step S2, salt is added to the water and the organic solvent after extraction to make the two phases separate; in step S2, 30%-40% hydrochloric acid aqueous solution is also used during extraction, and the amount of hydrochloric acid aqueous solution is 0.1%-0.5% of the volume of acetonitrile. In step S3, the purification comprises, in sequence, activation of the solid-phase extraction column, sample loading, elution and elution; the stationary phase of the solid-phase extraction column in step S3 is a mixture of WAX and HLB, wherein the mass ratio of WAX to HLB is 1: (0.5-2); the activation is performed in sequence using 0.05%-0.5% (by volume) of ammonia methanol, methanol and water; the elution liquid is ammonium acetate with a concentration of 10-50 mmol / L; and the elution is performed in sequence using methanol and 0.05%-0.5% (by volume) of ammonia methanol.

2. The detection method according to claim 1, characterized in that, In step S2, the amount of water added is 1-10 mL based on 1 g of the sample to be detected; and / or, the amount of salt added is 0.5-2.1 g based on 1 mL of water in step S2; and / or, the volume ratio of water to organic solvent in step S2 is 1: (1-5); and / or, step S2 further comprises adding an internal standard to the sample to be detected before extraction, and the amount of the internal standard added is 2-50 ng based on 1 g of the sample to be detected, and the internal standard is any one or more selected from M4PFBA, M5PFHxA, M8PFOA, MPFDoDA, M8PFOS, M2-8:2FTS and M3HFPO-DA.

3. The method of claim 1, wherein The mass of the stationary phase of the solid-phase extraction column is 100-200 mg; and / or, the volume of the solid-phase extraction column is 5-10 mL; and / or, the volume ratio of the mass of the stationary phase to the volume of the sample to be purified is 6 mg: (5-15) mL.

4. The method of claim 1, wherein, In step S4, the concentration is performed at 30-50°C using nitrogen blowing; and / or, in step S4, the redissolving is performed by redissolving the concentrate using methanol; and / or, in step S4, the filtration is performed using a filter membrane with a pore size of 0.1-0.3 μm.

5. The method of claim 1, wherein In step S5, the chromatographic conditions comprise: 1) the chromatographic column is a C18 column; 2) the column temperature is 35-45°C; 3) the sample injection volume is 1-5 μL; 4) the flow rate is 0.1-0.5 mL / min; 5) the mobile phase: A phase: 1-3 mM ammonium acetate aqueous solution, B phase: methanol; 6) elution mode: gradient elution, including: initial solvent composition: 75%-80% A phase and 20%-25% B phase, gradient change stage: 0-14 min, the proportion of B phase is linearly increased to 90%-95%, holding stage: 14-16 min, 90%-95% B phase is maintained, column cleaning stage: 16 min-16.01 min, the proportion of B phase is linearly decreased to 20%-25%; column equilibration stage: 16.01 min-20 min, 20%-25% B phase is maintained.

6. The method of claim 1, wherein In step S5, the mass spectrometry conditions comprise: 1) electrospray ion source, negative ion mode; 2) gas curtain gas pressure: 30-40 psi; 3) spray voltage: -4000 to -5000 V; 4) atomization temperature: 450-550°C; 5) atomization gas pressure: 45-55 psi; 6) auxiliary gas pressure: 45-55 psi; And / or, in step S5, the concentration of the standard solution selected in the standard curve establishment is 0.005-100 μg / L; And / or, in step S5, the standard curve establishment further comprises adding an internal standard, and the amount of the internal standard added is 5-15 ng.

7. Use of the method according to any one of claims 1-6 for simultaneously detecting 41 fluorinated compounds in crabs.

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