Method for simultaneously detecting contents of seven novel brominated flame retardants in shellfish seafood

Abstract

The invention relates to a method for simultaneously detecting seven novel brominated flame retardants in seafood shellfish. The method comprises the following steps: preparing a mixed standard working solution, a substitute standard working solution and a recovery rate indication standard working solution; drawing a standard working curve; pretreatment of the sample: weighing the sample, adding the substitute standard substance, performing Soxhlet extraction, adding concentrated sulfuric acid for degreasing, concentrating, performing chromatographic column purification, adding the recovery rate indication standard substance after concentration, and fixing the volume; gC-MS / MS is adopted for detection and analysis. According to the method disclosed by the invention, the interference problem of complex shellfish sample matrix is effectively solved by optimizing a pretreatment process, particularly adding concentrated sulfuric acid for degreasing, and the method is simple in pretreatment, high in sensitivity and strong in practicability and can be used for conventional detection or monitoring of the shellfish seafood NBFRs.

Description

Technical Field

[0001] This invention relates to the field of organic pollutant detection technology, specifically to a method for simultaneously detecting the content of seven novel brominated flame retardants in shellfish. Background Technology

[0002] Traditional brominated flame retardants (BFRs) are widely used in flammable materials industries such as plastics processing, textiles, electronics, building materials, furniture, and automotive parts due to their excellent flame-retardant properties. However, due to their persistent organic pollutant (POP) characteristics, pentabromodiphenyl ether (PDE) and octabromodiphenyl ether (OCD), which are used in large quantities among traditional BFRs, were first added to the Annex A restricted list of the Stockholm Convention in 2009, and decabromodiphenyl ether (DED) was added in 2017, subjecting them to strict control. Novel brominated flame retardants (NBFRs), with similar structures, functions, and application ranges to traditional BFRs, are being used as alternatives.

[0003] NBFRs are released into the environment at different stages throughout the entire lifecycle of commercial production. As NBFRs gradually replace BFRs, their usage and accumulation are steadily increasing. It is estimated that the annual accumulation of NBFRs will reach 1.5 million tons by 2025. Due to their semi-volatile and lipophilic nature, NBFRs are easily transported long distances through the atmosphere to different terrestrial and marine environments. After being ingested by organisms, they accumulate in areas with high lipid content and are transferred through food chains or food webs, gradually accumulating at higher trophic levels, creating a biomagnification effect. Multiple studies have shown that NBFRs have been detected in various environmental media, and in recent years they have also been increasingly detected in shellfish and other organisms. Shellfish, as benthic organisms, have a strong ability to accumulate lipid-soluble pollutants, making them ideal indicator organisms for assessing pollution levels and health risks in coastal areas. Furthermore, shellfish are an important part of the human diet in many regions. Therefore, a method for simultaneously detecting the content of multiple NBFRs in shellfish is needed to provide a scientific basis for understanding regional NBFR pollution levels, assessing seafood product safety, and evaluating dietary exposure risks in populations.

[0004] Existing technologies have been studied for the detection of NBFRs in the environment (such as water and soil). However, due to interference from shellfish lipids, these methods are not applicable to the detection of NBFRs in shellfish. Currently, no patents have been reported for methods to detect NBFRs in shellfish. Therefore, based on gas chromatography-tandem triple quadrupole mass spectrometry, we have established a detection method for NBFRs in shellfish that is comprehensive, relatively simple to operate, and highly sensitive, providing fundamental data for improving the assessment of NBFR concentrations in shellfish. Summary of the Invention

[0005] This application aims to provide a method for simultaneously detecting the content of seven novel brominated flame retardants in shellfish. By optimizing the sample pretreatment process, especially by using concentrated sulfuric acid to effectively remove interference from the high-lipid matrix of shellfish, and combining it with chromatography-mass spectrometry, the method can achieve simultaneous and accurate detection of multiple target pollutants, providing technical support for the safety monitoring and risk assessment of shellfish products.

[0006] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows: A method for simultaneously detecting multiple novel brominated flame retardants in seafood shellfish includes the following steps: S1: Prepare a mixed standard working solution containing multiple target novel brominated flame retardants; S2: Prepare a solution to replace the standard product; S3: Prepare the working solution for the recovery rate indicator standard; S4: Plot a standard working curve using the mixed standard working solution and the alternative standard working solution; S5: Pre-treatment of shellfish samples, the pre-treatment including: S51: Weigh the sample, add the aforementioned alternative standard solution as an internal standard for extraction, and obtain the extract; S52: Add concentrated sulfuric acid to the extract to remove fat; S53: Concentrate the degreased solution; S54: The concentrated solution is purified using a chromatography column, and the eluent is collected; S55: After concentrating the eluent, add the recovery rate indicator standard working solution and make up to volume to obtain the test solution; S6: The test solution is detected by gas chromatography-tandem mass spectrometry, and the results are analyzed according to the standard working curve.

[0007] Preferably, the various target novel brominated flame retardants include pentabromobenzene (PBBz), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), (2,3-dibromopropyl)(2,4,6-tribromopropyl) ether (DPTE), hexabromobenzene (HBBz), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and decabromodiphenyl ethane (DBDPE); the alternative standard solution contains BDE-77 and BDE-128; and the recovery indicator standard solution contains BDE-138.

[0008] Preferably, the mixed standard solution in step S1 is obtained by mixing and diluting single standard solutions of each target novel brominated flame retardant, wherein the concentrations of the single standard solutions of PBBz, PBT, PBEB, DPTE, HBBz, and BTBPE are 1000 μg / L, the concentration of the single standard solution of DBDPE is 5000 μg / L, and after mixing, the concentrations of PBBz, PBT, PBEB, DPTE, HBBz, and BTBPE are 100 μg / L, and the concentration of DBDPE is 500 μg / L.

[0009] Preferably, in step S4, when plotting the standard working curve, the mixed standard solution is diluted to a series of standard solutions with concentrations of 0.1, 0.2, 1, 5, 10, 25, 50, and 100 μg / L, and the substitute standard solution is added to each concentration standard solution. After detection, the ratio of the concentration of the target compound to the internal standard compound is used as the abscissa, and the ratio of the peak area of ​​the corresponding quantitative ion pair is used as the ordinate for fitting.

[0010] Preferably, the extraction in step S51 is carried out by Soxhlet extraction, and the extractant is a mixture of dichloromethane and n-hexane in a volume ratio of 1:1, and the extraction time is 24 hours; in step S52, 5 mL of concentrated sulfuric acid is added to the extract and the mixture is allowed to stand for 6 to 8 hours to remove fat.

[0011] Preferably, the packing material of the chromatography column in step S54, from bottom to top, is neutral silica gel, 30% acidic silica gel by mass, neutral silica gel, and anhydrous sodium sulfate; elution is performed using a 1:5 volume ratio of dichloromethane / n-hexane mixed solution.

[0012] Preferably, the gas chromatography-tandem mass spectrometry method described in step S6 is performed using a gas chromatography-tandem triple quadrupole mass spectrometer in multiple reaction monitoring mode.

[0013] Preferably, the gas chromatography conditions include: a DB-5MS capillary column with dimensions of 15m × 0.25mm × 0.1μm, an injection port temperature of 280℃, splitless injection, helium as the carrier gas, a flow rate of 1.5mL / min, and a programmed temperature increase as follows: an initial temperature of 90℃ held for 0.5 minutes, followed by a temperature increase at 40℃ / min to 325℃ and held for 6 minutes.

[0014] Preferably, the mass spectrometry conditions include: an EI ionization source, an ion source temperature of 280°C, an interface temperature of 300°C, and a detector voltage offset of 0.5 kV relative to the tuning result.

[0015] Preferably, in step S51, 1 gram of freeze-dried shellfish powder is weighed, and the amount of the substitute standard provided by the added substitute standard solution is 1 nanogram; in step S55, the volume is adjusted to 20 microliters, and the amount of the recovery rate indicator standard provided by the added recovery rate indicator solution is 1 nanogram.

[0016] Preferably, the alternative standard solution is obtained by diluting single standard solutions of BDE-77 and BDE-128 with nonane to 100 μg / L; the recovery indicator standard solution is obtained by diluting single standard solution of BDE-138 with nonane to 100 μg / L.

[0017] Preferably, the single-standard solution is prepared using nonane as a solvent.

[0018] Preferably, the concentration in steps S53 and S55 is carried out by a combination of rotary evaporation and nitrogen blowing.

[0019] Preferably, in step S55, n-hexane is used for volume adjustment, followed by vortex mixing and storage at 4°C for testing.

[0020] Compared with the prior art, this application has achieved the following beneficial effects: (1) This invention uses a Soxhlet extraction device to extract 7 NBFRs from shellfish and analyzes them by gas chromatography-tandem quadrupole mass spectrometry. A large number of optimization experiments were carried out on the chromatographic and mass spectrometry conditions and sample pretreatment methods in terms of linearity, accuracy, precision, detection limit and quantitation limit, so as to realize the simultaneous detection and analysis of 7 NBFRs in shellfish. (2) The spiked recovery test results of the present invention for shellfish showed that the recovery rate of the target NBFRs ranged from 61% to 115%, and the method detection limit was between 0.04 ng / g dw and 0.96 ng / g dw. The method has simple pretreatment, high sensitivity and strong practicality, and can be used for routine biological monitoring of NBFRs in shellfish. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments 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 the drawings without creative effort.

[0022] Figure 1The total ion chromatogram of the mixed standard solution of 7 NBFRs is shown. From left to right, the peaks represent PBBz, PBT, PBEB, DPTE, HBBz, BDE-77, BDE-138, BDE-128, BTBPE, and DBDPE, respectively. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. This application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Description of the reagents involved in this invention: In this invention, PBBz is pentabromobenzene, PBT is pentabromotoluene, PBEB is pentabromoethylbenzene, DPTE is (2,3-dibromopropyl)(2,4,6-tribromopropyl) ether, HBBz is hexabromobenzene, BTBPE is 1,2-bis(2,4,6-tribromophenoxy)ethane, DBDPE is decabromodiphenyl ethane, BDE-77 is 3,3',4,4'-tetrabromodiphenyl ether, BDE-128 is 2,2',3,3',4,4'-hexabromodiphenyl ether, and BDE-138 is 2,2',3,4,4',5'-hexabromodiphenyl ether.

[0025] In this invention, the purity of the following standards is as follows: PBBz standard: 50 μg / mL (>98%); PBT standard: 50 μg / mL (>98%); PBEB standard: 50 μg / mL (>98%); DPTE standard: 50 μg / mL (>98%); HBBz standard: 50 μg / mL (>98%); BTBPE standard: 50 μg / mL (>98%); DBDPE standard: 25 μg / mL (>98%). All of the above reagents were purchased from Wellington Laboratory (Canada). The purity of the following standards is as follows: BDE-77 standard: 50 μg / mL (>98%); BDE-128 standard: 50 μg / mL (>98%); BDE-138 standard: 50 μg / mL (>98%). μg / mL, with a purity >98%, the above reagents were purchased from AccuSimant Inc. (USA).

[0026] In this invention, acetone (pesticide residue grade) was purchased from Fisher Scientific Inc. Dichloromethane (DCM) (pesticide residue grade) and n-hexane (pesticide residue grade) were purchased from JT Bakers. Ultrapure water was prepared using a Milli-Q instrument (Millipore, Billerica, MA, USA). Silica gel (particle size 0.063-0.100 mm) and anhydrous sodium sulfate (Na2SO4) were purchased from Merck AG (Germany) and Tianjin Kemeiou Chemical Reagent Co., Ltd., respectively.

[0027] This application discloses a method for simultaneously detecting the content of seven novel brominated flame retardants in shellfish, the specific steps of which are as follows: S1: Preparation of mixed standard working solution: Accurately weigh appropriate amounts of PBBz, PBT, PBEB, DPTE, HBBz, and BTBPE standards respectively, and prepare a single standard solution with a concentration of 1000 μg / L using nonane; weigh an appropriate amount of DBDPE and prepare a single standard solution with a concentration of 5000 μg / L using nonane; use a syringe to draw 100 μL of each single standard solution into a vial; use a syringe to draw 300 μL of nonane and add it to the vial to prepare a mixed standard working solution with a concentration of 100 μg / L for PBBz, PBT, PBEB, DPTE, HBBz, and BTBPE, and a concentration of 500 μg / L for DBDPE, and label it as a mixed standard working solution with a concentration of 100 μg / L. S2: Preparation of alternative standard working solution: Using the injection needle, pipette 20 μL of BDE-77 and BDE-128 (50 μg / mL) into each vial, then use the injection needle to pipette 960 μL of nonane into the vial to prepare an alternative standard working solution with a concentration of 1000 μg / L; Using the injection needle, pipette 100 μL of the alternative standard working solution with a concentration of 1000 μg / mL into each vial, then use the injection needle to pipette 900 μL of nonane into the vial to prepare an alternative standard working solution with a concentration of 100 μg / L. S3: Prepare the working solution for the recovery rate standard: Pipette 20 μL of BDE-138 (50 μg / mL) into a vial using the syringe, then add 980 μL of nonane to the vial to prepare a 1000 μg / L recovery rate standard working solution; Pipette 100 μL of the 1000 μg / mL recovery rate standard working solution into a vial using the syringe, then add 900 μL of nonane to the vial to prepare a 100 μg / L recovery rate standard working solution. S4: Plotting Standard Working Curves: Dilute the mixed standard solution to prepare mixed standard solutions with concentrations of 0.1, 1, 5, 10, 25, 50, and 100 μg / L respectively. Use a syringe to draw 10 μL of a 100 μg / L substitute standard solution and add it to each concentration of mixed standard solution, leaving it for instrumental analysis. This will yield a series of working curves with concentrations of 0.1, 1, 5, 10, 25, 50, and 100 μg / L. Finally, plot the standard working curves using the mass concentration ratio x of the compound to the internal standard versus the peak area ratio y of their quantitative ion pairs.

[0028] S5: Sample Pretreatment: After freeze-drying, the shellfish samples were thawed at room temperature, thoroughly washed with tap water and ultrapure water, and dissected to remove impurities. The soft tissue of the shellfish was cut out with a stainless steel blade. Approximately 500-1000 g of wet soft tissue from the same species was homogenized in a mixer to form a composite sample, and the edible portions were collected. Before processing each species, all equipment and storage containers were thoroughly rinsed with ultrapure water and methanol. The homogenized composite sample was packaged in aluminum foil and freeze-dried (-50℃, 0.12 mbar). After freeze-drying, the shellfish sample was ground into a fine powder and frozen at -20℃. 1 g of freeze-dried shellfish was weighed and mixed with anhydrous sodium sulfate. 1 ng of a substitute standard (10 μL of a 100 μg / L substitute standard solution was injected using a syringe) was added as an internal standard. Soxhlet extraction was performed with 200 mL of extraction buffer for 24 hours. h; After extraction, add 5 mL of concentrated sulfuric acid to remove fat, let stand for 6-8 hours, transfer the supernatant, and concentrate by rotary evaporation to 2-3 mL; transfer the concentrated sample solution to a chromatography column for purification (column length 30.0 cm, inner diameter 1.6 cm). Before loading the sample, pre-wash the chromatography column with 60 mL of n-hexane, add the concentrated sample after rotary evaporation, and elute with 90 mL of dichloromethane / n-hexane (1:5, v / v); collect all eluent, rotary evaporate, blow with nitrogen to near dryness, add 1 ng of recovery standard (take 10 μL of 100 μg / L recovery standard working solution using a syringe), and dilute to 20 μL with n-hexane, then turbine mix and refrigerate at 4℃ for analysis.

[0029] S6: Detection and Result Analysis: Gas chromatography-tandem triple quadrupole mass spectrometry was used to detect and analyze the content of the novel brominated flame retardant.

[0030] Furthermore, seven novel brominated flame retardants were simultaneously tested, including PBBz, PBT, PBEB, DPTE, HBBz, BTBPE, and DBDPE.

[0031] Furthermore, in S2, the substitute standard BDE-77 is 3,3',4,4'-tetrabromodiphenyl ether and BDE-128 is 2,2',3,3',4,4'-hexabromodiphenyl ether.

[0032] Furthermore, the recovery standard BDE-138 in S3 is 2,2',3,4,4',5'-hexabromodiphenyl ether. Furthermore, the Soxhlet extraction solution in S5 is a mixture of dichloromethane and n-hexane in a volume ratio of 1:1.

[0033] Furthermore, the chromatography column in S5 is packed with the following components from bottom to top: 1 g of neutral silica gel, 8 g of acidic silica gel (30%, w / w), 1 g of neutral silica gel, and 4 g of anhydrous sodium sulfate.

[0034] Furthermore, the gas chromatograph-mass spectrometer in S6 is a Shimadzu TQ-8050NX gas chromatograph-tandem triple quadrupole mass spectrometer.

[0035] Furthermore, the gas chromatographic conditions for the gas chromatography-tandem triple quadrupole mass spectrometer are as follows: The chromatographic column was a DB-5MS capillary column with a sample port temperature of 280℃. Splitless injection was used, with helium as the carrier gas at a flow rate of 1.5 mL / min. The temperature program conditions were: initial temperature 90℃ held for 0.5 min, then increased to 325℃ at 40℃ / min and held for 6 min.

[0036] Furthermore, the DB-5MS capillary column has dimensions of 15 m × 0.25 mm × 0.1 μm. Furthermore, the mass spectrometry conditions are as follows: An EI source was used with an ion source temperature of 280°C and an interface temperature of 300°C. Multiple reaction monitoring (MRM) mode was employed for acquisition, and the qualitative and quantitative ion pairs and collision voltages of the target analyte were optimized. The detector voltage was set to 0.5 kV relative to the tuning results.

[0037] The following is a further description with reference to the embodiments: Example 1: Gas Chromatography and Mass Spectrometry Conditions 1. Gas chromatography conditions The chromatographic column was a DB-5MS capillary column (15 m × 0.25 mm × 0.1 μm, Agilent Technologies, USA). The sample port temperature was 280℃, and the injection was splitless. The carrier gas was helium, and the flow rate was 1.5 mL / min. The temperature program conditions were: initial temperature 90℃ held for 0.5 min, then increased to 325℃ at 40℃ / min and held for 6 min.

[0038] 2. Mass spectrometry conditions The EI source was used, with an ion source temperature of 280°C and an interface temperature of 300°C. Multiple reaction monitoring (MRM) mode was employed, and the qualitative and quantitative ion pairs and collision voltages of the target analyte were optimized. The detector voltage was set to 0.5 kV relative to the tuning results. The solvent delay time was 3.00 min; the residence time was adjusted to 0.15–0.3 sec based on the number of characteristic ion pairs in each time window. Other mass spectrometry parameters are shown in Table 1.

[0039] Table 17 Retention times, ion pair parameters, and collision energies of NBFRs and internal standards

[0040] The above-mentioned mixed standard solution of NBFRs was analyzed and determined under the above conditions, and the results are as follows: Figure 1 As shown, the seven NBFRs mixed solutions exhibited good separation within 12 minutes, with symmetrical peak shapes.

[0041] Example 2 Method Verification 1. Linear range of the working curve, regression equation, limit of detection, and limit of quantitation. Within the linear range of 0.1–100 ng / g, the regression equations for all NBFRs showed good linearity. The blank sample preparation solution was spiked at a concentration of 1.0 ng / mL. The detection limit was set at a signal-to-noise ratio (SNR) of 3 and a SNR of 10, as detailed in Table 2.

[0042] Table 2. Regression equations, limits of detection, and limits of quantitation for seven NBFRs in shellfish using gas chromatography-tandem mass spectrometry.

[0043] Using a shellfish matrix as a background, a matrix spiked recovery experiment was conducted by adding a mixed standard solution of seven NBFRs at low (1 ng absolute amount) and high (5 ng absolute amount) concentrations. The results were performed in triplicate and are shown in Table 3. The average recovery rate of this method ranged from 59% to 115%.

[0044] Table 3. Matrix spiked recoveries of seven NBFRs in shellfish.

[0045] Example 3: Determination of actual samples The method established in this study was used to analyze shellfish from a city in Zhejiang Province. The results are shown in Table 4. All seven NBFRs were detected in the shellfish. DBDPE had the highest detection rate at 100%, while BTBPE had the lowest at 3%. The concentration range of ΣNBFRs in the shellfish was 27.8 - 364 ng / g dw.

[0046] Table 4. Detection results of NBFRs in shellfish in a city in Zhejiang Province (ng / g dw)

[0047] As can be seen from the above, the method of the present invention has simple pretreatment, high sensitivity, and strong practicality, and can be used for routine biological monitoring of NBFRs in shellfish.

[0048] This invention provides a method for simultaneously detecting the content of seven novel brominated flame retardants (NBFRs) in shellfish. The spiked recovery test results show that the recovery rate of the target NBFRs ranges from 61% to 115%, and the method detection limit is between 0.04 ng / g dw and 0.96 ng / g dw. The method of this invention has simple pretreatment, high sensitivity, and strong practicality, and can be used for routine biomonitoring of NBFRs in shellfish.

[0049] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for simultaneously detecting the content of 7 new types of brominated flame retardants in shellfish seafood, characterized in that, The method comprises the following steps: S1: preparing a mixed standard solution containing a plurality of target novel brominated flame retardants; S2: preparing a substitute standard solution; S3: preparing a recovery indicating standard solution; S4: drawing a standard working curve by using the mixed standard solution and the substitute standard solution; S5: performing pretreatment on a shellfish sample, which comprises: S51: weighing the sample, adding the substitute standard solution as an internal standard for extraction, and obtaining an extracted solution; S52: adding concentrated sulfuric acid to the extracted solution to remove fat; S53: concentrating the solution after fat removal; S54: purifying the concentrated solution by using a chromatographic column, and collecting an eluent; S55: after concentrating the eluent, adding the recovery indicating standard solution and constant volume to obtain a to-be-tested solution; S6: detecting the to-be-tested solution by using gas chromatography-tandem mass spectrometry, and analyzing the result according to the standard working curve.

2. The method of claim 1, wherein, The plurality of target novel brominated flame retardants comprise pentabromobenzene (PBBz), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), (2,3-dibromopropyl) (2,4,6-tribromopropyl) ether (DPTE), hexabromobenzene (HBBz), 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE) and decabromodiphenyl ethane (DBDPE); the substitute standard solution contains BDE-77 and BDE-128; and the recovery indicating standard solution contains BDE-138.

3. The method of claim 1, wherein, In step S1, the mixed standard solution is obtained by mixing single standard solutions of the target novel brominated flame retardants and dilution, wherein the PBBz, PBT, PBEB, DPTE, HBBz, BTBPE single standard solution concentration is 1000 μg / L, the DBDPE single standard solution concentration is 5000 μg / L, the PBBz, PBT, PBEB, DPTE, HBBz, BTBPE concentration after mixing is 100 μg / L, and the DBDPE concentration is 500 μg / L.

4. The method of claim 1, wherein, In step S4, when drawing the standard working curve, the mixed standard solution is diluted into series standard solutions with concentrations of 0.1, 0.2, 1, 5, 10, 25, 50 and 100 μg / L, the substitute standard solution is added to each concentration standard solution, and after detection, the concentration ratio of the target compound to the internal standard compound is taken as the abscissa, and the corresponding quantitative ion pair peak area ratio is taken as the ordinate for fitting.

5. The method of claim 1, wherein, In step S51, the extraction is performed by using Soxhlet extraction, the extraction agent is a mixed solvent of dichloromethane and n-hexane with a volume ratio of 1:1, and the extraction time is 24 hours; in step S52, 5 mL of concentrated sulfuric acid is added to the extracted solution, and the solution is statically placed for 6 to 8 hours to remove fat.

6. The method of claim 1, wherein, In step S54, the filling material of the chromatographic column is, from bottom to top, neutral silica gel, acid silica gel with a mass fraction of 30%, neutral silica gel and anhydrous sodium sulfate; and a mixed solution of dichloromethane / n-hexane with a volume ratio of 1:5 is used for elution.

7. The method of claim 1, wherein, The gas chromatography-tandem mass spectrometry in step S6 is detected by using a gas chromatography-tandem triple quadrupole mass spectrometer in a multiple reaction monitoring mode.

8. The method of claim 7, wherein, The gas chromatography conditions include: a DB-5MS capillary chromatographic column with a specification of 15m*0.25mm*0.1μm, an injection port temperature of 280℃, non-split injection, helium as the carrier gas, a flow rate of 1.5mL / min, and a programmed temperature process of: an initial temperature of 90℃ for 0.5min, then increasing the temperature to 325℃ at a rate of 40℃ / min and keeping for 6min.

9. The method of claim 7, wherein, The mass spectrometry conditions include: an EI ionization source, an ion source temperature of 280℃, an interface temperature of 300℃, and a detector voltage offset of 0.5kV relative to the tuning result.

10. The method of claim 1, wherein, In step S51, 1g of the freeze-dried shellfish powder is weighed, and the amount of the surrogate standard provided by the surrogate standard solution is 1ng; in step S55, the constant volume is 20μL, and the amount of the recovery indicator standard provided by the recovery indicator standard solution is 1ng.

11. The method of claim 2, wherein, The surrogate standard solution is obtained by diluting a single standard solution of BDE-77 and BDE-128 to 100μg / L with nonane; and the recovery indicator standard solution is obtained by diluting a single standard solution of BDE-138 to 100μg / L with nonane.

12. The method of claim 3, wherein, The single standard solution is prepared by using nonane as the solvent.

13. The method of claim 1, wherein, The concentration in steps S53 and S55 is performed by using a combination of rotary evaporation and nitrogen blowing.

14. The method of claim 1, wherein, In step S55, n-hexane is used for constant volume, and after constant volume, vortex mixing is performed, and the sample is stored at 4℃ for detection.

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