Method for detecting polychlorinated naphthalene in food

Abstract

The invention relates to the technical field of food detection, in particular to a method for detecting polychlorinated naphthalene in food. The method for detecting polychlorinated naphthalene in food comprises the following steps: extracting a homogeneous food sample by using a mixed solution of n-hexane and dichloromethane, centrifuging, taking supernate, carrying out nitrogen blowing until the supernate is nearly dry, and dissolving by using n-hexane; a solid-phase extraction column of pentafluorophenyl bonded silica gel is adopted to purify a sample solution, and interferents such as grease are effectively removed by optimizing activation, sample loading, leaching and elution of a solvent system; carrying out nitrogen blowing concentration and solvent replacement on the purified eluent, detecting in a multi-reaction monitoring mode by adopting a gas chromatography-tandem mass spectrometry method, and quantifying by adopting an internal standard method; the detection method provided by the invention has the advantages of high pretreatment efficiency, good purification effect, capability of remarkably reducing matrix interference, high sensitivity, good accuracy, simplicity and convenience in operation and the like, and is suitable for simultaneously detecting various polychlorinated naphthalene homologues in animal-derived and plant-derived foods.

Description

A method for detecting polychlorinated naphthalene in food Technical Field

[0001] This invention relates to the field of food testing technology, specifically a method for detecting polychlorinated naphthalene in food. Background Technology

[0002] Polychlorinated naphthalenes (PCNAs) are a class of persistent organic pollutants formed by replacing varying numbers of hydrogen atoms on a naphthalene ring with chlorine atoms; there are 75 such compounds. These compounds are not only toxic themselves, but can also produce dioxin-like toxic effects by binding to aromatic hydrocarbon acceptors. Their persistence, bioaccumulation, and long-distance migration in the environment have led to their detection in food worldwide, posing a potential threat to human health.

[0003] Currently, the analytical techniques for polychlorinated naphthalenes in food face multiple challenges. First, polychlorinated naphthalenes with different degrees of chlorination exhibit significant differences in physicochemical properties, ranging from the volatility of low-chlorinated compounds to the low volatility of high-chlorinated compounds, making the simultaneous extraction and detection of all similar compounds difficult. Second, the food matrix is ​​complex and diverse, including interfering substances such as cellulose and pigments in plant-based foods, as well as components such as proteins and lipids in animal-based foods. These matrix effects can severely impact the accuracy of analytical results.

[0004] In sample pretreatment, traditional extraction methods such as Soxhlet extraction are time-consuming, accelerated solvent extraction requires specialized equipment, and conventional solid-phase extraction methods have limited efficiency when simultaneously purifying similar compounds with multiple degrees of chlorination. While pentafluorophenyl (PFP)-bonded silica gel has been used in HPLC columns, its application as a solid-phase extraction packing material for the detection of polychlorinated naphthalenes in food has not been reported. In instrumental analysis, although gas chromatography-triple quadrupole mass spectrometry (GC-MS) offers good sensitivity, it still faces interference from co-extractants in complex food matrices, making it difficult for the method's detection limit to meet increasingly stringent requirements.

[0005] Based on the above, the present invention provides a method for detecting polychlorinated naphthalene in food to solve the aforementioned technical problems. Summary of the Invention

[0006] The detection method provided by this invention is based on the charge-transfer π-π interaction between the electron-deficient aromatic ring of pentafluorophenyl and the electron-rich naphthalene ring of polychlorinated naphthalene, achieving highly selective enrichment. It has the advantages of efficient pretreatment, good purification effect, significant reduction of matrix interference, high sensitivity, good accuracy and simple operation. It is suitable for the simultaneous detection of multiple polychlorinated naphthalene homologues in animal and plant-derived foods.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for detecting polychlorinated naphthalene in food, comprising the following steps: Step 1, Sample preparation and solvent extraction: Accurately weigh the homogenized food sample and place it in a centrifuge tube. Add a mixed extraction solution composed of n-hexane and dichloromethane to the centrifuge tube, add anhydrous sodium sulfate, seal the tube, and vortex mix for 1-3 minutes. Further ultrasonic extraction is then performed for 15 minutes. Step 2, Centrifugation: Centrifuge the mixture obtained after vortex extraction to fully separate the solid and liquid phases. Carefully aspirate the supernatant using a pipette to obtain the crude extract. Nitrogen-purge the extract to near dryness, add 2 mL of n-hexane to dissolve, and obtain the sample solution. Step 3, Solid-phase extraction column purification: I. Activation: Activate the solid-phase extraction column sequentially using dichloromethane and n-hexane. II. Loading: Load the sample solution onto the activated solid-phase extraction column, allowing it to flow out under gravity. Discard the waste liquid flowing out during this process. III. Washing: Use 5... IV. Elution: Add 6 mL of a mixed eluent consisting of hexane and dichloromethane to the column for elution, and collect all the eluent from this step in a concentration tube; VI. Concentration and Solvent Replacement: Place the eluent collected in step III in a water bath at 30-45℃ and concentrate it to near dryness under a nitrogen stream; then redissolve and dilute with hexane; after vortex mixing, filter through a 0.45 μm filter membrane and transfer to a sample vial to obtain the sample solution to be tested; VII. Detection and Quantification: Prepare a series of polychlorinated naphthalene standard working solutions, and inject the sample solution to be tested and the polychlorinated naphthalene standard working solutions obtained in step IV into a gas chromatography-tandem mass spectrometry (GC-MS) instrument for analysis; GC separation uses a DB-5MS capillary column, and mass spectrometry detection uses an electron impact ion source and multiple reaction monitoring mode; by comparing the peak area ratio of the target polychlorinated naphthalene to the internal standard in the sample solution to be tested, and referring to the pre-plotted internal standard curve, calculate the content of polychlorinated naphthalene in the food sample.

[0008] Furthermore, the volume ratio of hexane to dichloromethane in the mixed extract composed of hexane and dichloromethane is 1:0.8-1.2.

[0009] Furthermore, the ratio of the mass of the food sample to the volume of the extraction solution is preferably 1 g: (10-15) mL.

[0010] Furthermore, the centrifugal separation speed is set to 4000-5000 r / min, and the centrifugal separation time is set to 5-10 min.

[0011] Furthermore, the solid-phase extraction column is a pentafluorophenyl-bonded silica gel solid-phase extraction column, wherein the pentafluorophenyl-bonded silica gel is prepared by coupling 3-(pentafluorophenyl)propyltrimethoxysilane with spherical silica gel. The synthesis method is as follows: the spherical silica gel is dried under vacuum at 100-120℃ for 2-6 h; the dried silica gel is dispersed in anhydrous toluene, and 3-(pentafluorophenyl)propyltrimethoxysilane and a catalytic amount of triethylamine are added; under nitrogen protection, the reaction is refluxed at 70-90℃ for 18-30 h; after the reaction is completed, the mixture is filtered, washed successively with toluene, anhydrous ethanol and n-hexane, and dried under vacuum at 60-80℃ to obtain pentafluorophenyl-bonded silica gel; wherein the mass ratio of 3-(pentafluorophenyl)propyltrimethoxysilane to silica gel is 0.2-0.5:1; and the solid-phase extraction column is a solid-phase extraction column with pentafluorophenyl-bonded silica gel as the packing material, with a specification of 100 mg / mL.

[0012] Furthermore, the method for plotting the internal standard curve includes the following steps: First, accurately transfer mixed standard working solutions of polychlorinated naphthalenes at different concentrations and add them to centrifuge tubes respectively. Then, add an equal amount of polychlorinated naphthalene isotope internal standard working solution to each centrifuge tube as the sample to be tested, and prepare a series of standard curve points with known concentrations. Second, plot the internal standard curve with the peak area ratio of the target polychlorinated naphthalene and the corresponding isotope internal standard as the ordinate and the mass concentration ratio as the abscissa to obtain the linear regression equation.

[0013] Furthermore, in the mixed eluent composed of hexane and dichloromethane, the volume ratio of hexane to dichloromethane is 1:0.8-1.2.

[0014] Furthermore, the chromatographic and mass spectrometric conditions included: gas chromatograph with ECD detector; column: DB-5MS capillary column; column temperature: initial temperature 100℃, held for 2 min; ramped up to 300℃ at a rate of 10℃ / min, held for 10 min; injector temperature: 280℃; 1 μL splitless injection; carrier gas: nitrogen, flow rate: 1 mL / min; detector temperature: 300℃; make-up nitrogen flow rate: 60 mL / min; and monitoring mode: multiple reaction monitoring (MRM).

[0015] Furthermore, the series of polychlorinated naphthalene standard working solutions contains an isotopic internal standard. 13 C 12 The labeled polychlorinated naphthalene; the polychlorinated naphthalene includes one or more combinations of 1-chloronaphthalene, 1,5-dichloronaphthalene, 1,2,3-trichloronaphthalene, 1,2,3,4-tetrachloronaphthalene, 1,2,3,5,7-pentachloronaphthalene, 1,2,3,4,6,7-hexachloronaphthalene, 1,2,3,4,5,6,7-heptachloronaphthalene, and octachloronaphthalene.

[0016] Furthermore, the food samples include animal-derived foods and plant-derived foods; the animal-derived foods are pork, chicken, fish, eggs, or milk; the plant-derived foods are grains, flour, or vegetables.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: 1. This invention uses a high-proportion mixed solution of n-hexane and dichloromethane as the extractant, combined with vortex and oscillation-assisted extraction, which can effectively extract polychlorinated naphthalenes from different food matrices (including animal-derived and plant-derived foods), with high and stable recovery rates. The optimized liquid-to-solid ratio ensures sufficient extraction. Furthermore, this invention uses a solid-phase extraction column of pentafluorophenyl-bonded silica gel for purification. Based on the charge-transfer type π-π interaction between the electron-deficient aromatic ring of pentafluorophenyl and the electron-rich naphthalene ring of polychlorinated naphthalene, highly selective enrichment is achieved. It has the advantages of efficient pretreatment, good purification effect, significant reduction of matrix interference, high sensitivity, good accuracy, simple operation, significantly reduced matrix effect, and improved signal-to-noise ratio.

[0018] 2. This invention combines gas chromatography-tandem mass spectrometry (GC-MS) with multiple reaction monitoring (MRM) mode, effectively eliminating the influence of coexisting interfering substances in complex matrices, and achieving accurate qualitative and quantitative analysis of trace polychlorinated naphthalenes. The use of isotope internal standard quantification corrects for losses during pretreatment and fluctuations in instrument response, significantly improving the accuracy and precision of the analytical results.

[0019] 3. Compared to traditional Soxhlet extraction and gel permeation chromatography purification, the extraction and purification steps of this invention are simpler, less time-consuming, and require less organic solvent. Compared to expensive high-resolution mass spectrometry, GC-MS / MS is more widely available, making this method easier to promote and apply in routine testing laboratories. Furthermore, this invention can simultaneously detect multiple homologues from monochloronaphthalene to octachloronaphthalene, covering the main congeners of polychlorinated naphthalenes, thus meeting the comprehensive requirements of food safety monitoring. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: Detection of Polychlorinated Naphthalene in Pork Step 1: Sample Preparation and Solvent Extraction: Accurately weigh 5g of homogenized pork sample and place it in a centrifuge tube. Add 20mL of a mixed extraction solution consisting of equal volumes of n-hexane and dichloromethane to the centrifuge tube, add 10g of anhydrous sodium sulfate, seal the tube, and vortex mix for 1min. Further ultrasonic extraction is then performed for 15min. Step 2: Centrifugation: Centrifuge the extracted mixture at 5000r / min for 10min. Carefully aspirate the supernatant using a pipette to obtain the crude extract. Nitrogen-purge the extract to near dryness, add 2mL of n-hexane to dissolve, and obtain the sample solution.

[0022] Step 3, Solid-phase extraction column purification: I. Activation: Take a 1000mg, 12mL solid-phase extraction column of pentafluorophenyl bonded silica gel and pass it through the column in sequence with 2mL of dichloromethane and 2mL of n-hexane to activate the packing material and replace the solvent.

[0023] II. Sample loading: Load the sample solution onto the activated solid-phase extraction column, where it flows out under gravity. Discard the waste liquid flowing out during this process.

[0024] III. Eluting: Elute with 5 mL of n-hexane to remove impurities; IV. Elution: Add 6 mL of a mixed eluent consisting of equal volumes of n-hexane and dichloromethane to the column for elution, and collect all the eluent from this step in a concentration tube; IV. Concentration and Solvent Replacement: Place the collected eluent in a 40°C water bath and purge and concentrate to near dryness under a nitrogen stream. Then redissolve and bring to volume with 1.0 mL of n-hexane; after vortex mixing, filter through a 0.45 μm filter membrane and transfer to a sample vial to obtain the sample solution to be tested.

[0025] Step 5: Detection and Quantification: Prepare a series of polychlorinated naphthalene standard working solutions, and inject the obtained test sample solution and polychlorinated naphthalene standard working solutions into a gas chromatograph-tandem mass spectrometer for analysis. By comparing the peak area ratio of the target polychlorinated naphthalene to the internal standard in the test sample solution, and referring to the pre-plotted internal standard curve, calculate the content of polychlorinated naphthalene in the pork sample.

[0026] The relevant data on polychlorinated naphthalene in the final obtained pork are shown in the table below: Table 1

[0027] Example 2: Detection of Polychlorinated Naphthalene in Milk Step 1: Sample Preparation and Solvent Extraction: Accurately weigh 5g of milk sample and place it in a centrifuge tube. Add 20mL of a mixed extraction solution consisting of equal volumes of n-hexane and dichloromethane to the centrifuge tube, add 10g of anhydrous sodium sulfate, seal the tube, and vortex mix for 2min. Further ultrasonic extraction is then performed for 15min. Step 2: Centrifugation: Centrifuge the extracted mixture at 5000r / min for 10min. Carefully aspirate the supernatant using a pipette to obtain the crude extract. Nitrogen-purge the extract to near dryness, add 2mL of n-hexane to dissolve, and obtain the sample solution.

[0028] Step 3, Solid-phase extraction column purification: I. Activation: Take a 1000mg, 12mL solid-phase extraction column of pentafluorophenyl bonded silica gel and pass it through the column in sequence with 2mL of dichloromethane and 2mL of n-hexane to activate the packing material and replace the solvent.

[0029] II. Sample loading: Load the sample solution onto the activated solid-phase extraction column, where it flows out under gravity. Discard the waste liquid flowing out during this process.

[0030] III. Eluting: Elute with 5 mL of n-hexane to remove impurities; IV. Elution: Add 6 mL of a mixed eluent consisting of equal volumes of n-hexane and dichloromethane to the column for elution, and collect all the eluent from this step in a concentration tube; IV. Concentration and Solvent Replacement: Place the collected eluent in a 40°C water bath and purge and concentrate to near dryness under a nitrogen stream. Then redissolve and bring to volume with 1.0 mL of n-hexane; after vortex mixing, filter through a 0.45 μm filter membrane and transfer to a sample vial to obtain the sample solution to be tested.

[0031] Step 5: Detection and Quantification: Prepare a series of polychlorinated naphthalene standard working solutions, and inject the obtained test sample solution and polychlorinated naphthalene standard working solutions into a gas chromatograph-tandem mass spectrometer for analysis. By comparing the peak area ratio of the target polychlorinated naphthalene to the internal standard in the test sample solution, and referring to the pre-plotted internal standard curve, calculate the content of polychlorinated naphthalene in the milk sample.

[0032] The relevant data on polychlorinated naphthalene in the final milk are shown in the table below: Table 2

[0033] Example 3: Detection of Polychlorinated Naphthalene in Wheat Step 1: Sample Preparation and Solvent Extraction: Accurately weigh 5g of homogenized wheat sample and place it in a centrifuge tube. Add 20mL of a mixed extraction solution consisting of equal volumes of n-hexane and dichloromethane to the centrifuge tube, add 10g of anhydrous sodium sulfate, seal the tube, and vortex mix for 3min. Further ultrasonic extraction is then performed for 15min. Step 2: Centrifugation: Centrifuge the extracted mixture at 5000r / min for 10min. Carefully aspirate the supernatant using a pipette to obtain the crude extract. Nitrogen-purge the extract to near dryness, add 2mL of n-hexane to dissolve, and obtain the sample solution.

[0034] Step 3, Solid-phase extraction column purification: I. Activation: Take a 1000mg, 12mL solid-phase extraction column of pentafluorophenyl bonded silica gel and pass it through the column in sequence with 2mL of dichloromethane and 2mL of n-hexane to activate the packing material and replace the solvent.

[0035] II. Sample loading: Load the sample solution onto the activated solid-phase extraction column, where it flows out under gravity. Discard the waste liquid flowing out during this process.

[0036] III. Eluting: Elute with 5 mL of n-hexane to remove impurities; IV. Elution: Add 6 mL of a mixed eluent consisting of equal volumes of n-hexane and dichloromethane to the column for elution, and collect all the eluent from this step in a concentration tube; IV. Concentration and Solvent Replacement: Place the collected eluent in a 40°C water bath and purge and concentrate to near dryness under a nitrogen stream. Then redissolve and bring to volume with 1.0 mL of n-hexane; after vortex mixing, filter through a 0.45 μm filter membrane and transfer to a sample vial to obtain the sample solution to be tested.

[0037] Step 5, Detection and Quantification: Prepare a series of polychlorinated naphthalene standard working solutions, and inject the obtained test sample solution and polychlorinated naphthalene standard working solutions into a gas chromatograph-tandem mass spectrometer for analysis. By comparing the peak area ratio of the target polychlorinated naphthalene to the internal standard in the test sample solution, and referring to the pre-plotted internal standard curve, calculate the content of polychlorinated naphthalene in the wheat sample; the relevant data of polychlorinated naphthalene in wheat are shown in the following table: Table 3

[0038] The data in the table show that the detection method provided by this invention has advantages such as high efficiency in pretreatment, good purification effect, significant reduction of matrix interference, high sensitivity, good accuracy, and simple operation. It is suitable for the simultaneous detection of multiple polychlorinated naphthalene homologues in animal-derived and plant-derived foods. This indicates that the detection method for polychlorinated naphthalenes in food provided by this invention has a broader market prospect and is more suitable for widespread application.

[0039] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for detecting polychlorinated naphthalene in food, characterized in that, Includes the following steps: Step 1, Sample Preparation and Solvent Extraction: Accurately weigh the homogenized food sample and place it in a centrifuge tube. Add a mixed extraction solution consisting of n-hexane and dichloromethane to the centrifuge tube, add anhydrous sodium sulfate, seal the tube, and vortex mix for 1-3 minutes. Then, further extract using ultrasound for 15 minutes. Step 2, Centrifugation: Centrifuge the mixture obtained after vortex extraction to fully separate the solid and liquid phases. Carefully aspirate the supernatant using a pipette to obtain the crude extract. Nitrogen-purge the extract to near dryness, add 2 mL of n-hexane to dissolve, and obtain the sample solution. Step 3, Solid-Phase Extraction Column Purification: I. Activation: Activate the solid-phase extraction column sequentially using dichloromethane and n-hexane. II. Sample Loading: Load the sample solution onto the activated solid-phase extraction column, allowing it to elute under gravity. Discard the waste liquid eluding during this process. III. Eluting: Elute with 5 mL of n-hexane to remove impurities. IV. Elution: Add 6 mL of hexane to the column. Elute with a mixed eluent of hexane and dichloromethane, and collect all the eluent from this step in a concentration tube; Step 4, Concentration and Solvent Replacement: Place the eluent collected in Step 3 in a water bath at 30-45℃ and concentrate it to near dryness under a nitrogen stream; then redissolve and dilute with hexane; after vortex mixing, filter through a 0.45μm filter membrane and transfer to a sample vial to obtain the sample solution to be tested; Step 5, Detection and Quantification: Prepare a series of polychlorinated naphthalene standard working solutions, and inject the sample solution to be tested and the polychlorinated naphthalene standard working solutions obtained in Step 4 into a gas chromatography-tandem mass spectrometry (GC-MS) instrument for analysis; GC separation uses a DB-5MS capillary column, and mass spectrometry detection uses an electron impact ion source and multiple reaction monitoring mode; by comparing the peak area ratio of the target polychlorinated naphthalene to the internal standard in the sample solution to be tested, and referring to the pre-plotted internal standard curve, calculate the content of polychlorinated naphthalene in the food sample.

2. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that: The volume fraction of hexane to dichloromethane in the mixed extract composed of hexane and dichloromethane is 1:0.8-1.

2.

3. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that: The preferred ratio of the mass of the food sample to the volume of the extraction solution is 1 g: (10-15) mL.

4. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that: The centrifugation speed is set to 4000-5000 r / min, and the centrifugation time is set to 5-10 min.

5. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that, The solid-phase extraction column is a solid-phase extraction column for pentafluorophenyl-bonded silica gel, wherein the pentafluorophenyl-bonded silica gel is prepared by coupling 3-(pentafluorophenyl)propyltrimethoxysilane with spherical silica gel. The synthesis method is as follows: the spherical silica gel is dried under vacuum at 100-120℃ for 2-6 h; the dried silica gel is dispersed in anhydrous toluene, and 3-(pentafluorophenyl)propyltrimethoxysilane and a catalytic amount of triethylamine are added; under nitrogen protection, the reaction is refluxed at 70-90℃ for 18-30 h; after the reaction is completed, the mixture is filtered, washed successively with toluene, anhydrous ethanol and n-hexane, and dried under vacuum at 60-80℃ to obtain pentafluorophenyl-bonded silica gel; wherein the mass ratio of 3-(pentafluorophenyl)propyltrimethoxysilane to silica gel is 0.2-0.5:

1.

6. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that, The method for plotting the internal standard curve includes the following steps: First, accurately transfer mixed standard working solutions of polychlorinated naphthalene at different concentrations and add them to centrifuge tubes respectively. Then, add an equal amount of polychlorinated naphthalene isotope internal standard working solution to each centrifuge tube as the sample to be tested, and prepare a series of standard curve points with known concentrations. Second, plot the internal standard curve with the peak area ratio of the target polychlorinated naphthalene and the corresponding isotope internal standard as the ordinate and the mass concentration ratio as the abscissa to obtain the linear regression equation.

7. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that, In the mixed eluent composed of hexane and dichloromethane, the volume ratio of hexane to dichloromethane is 1:0.8-1.

2.

8. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that, Chromatographic and mass spectrometric conditions included: gas chromatograph with ECD detector; column: DB-5MS capillary column; column temperature: initial temperature 100℃, hold for 2 min; ramp up to 300℃ at a rate of 10℃ / min, hold for 10 min; injector temperature: 280℃; splitless injection of 1 μL; carrier gas: nitrogen, flow rate: 1 mL / min; detector temperature: 300℃; make-up nitrogen flow rate: 60 mL / min; monitoring mode: multiple reaction monitoring (MRM).

9. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that: The isotopic internal standard used in the internal standard method is: 13 C 12 The labeled polychlorinated naphthalene; the polychlorinated naphthalene includes one or more combinations of 1-chloronaphthalene, 1,5-dichloronaphthalene, 1,2,3-trichloronaphthalene, 1,2,3,4-tetrachloronaphthalene, 1,2,3,5,7-pentachloronaphthalene, 1,2,3,4,6,7-hexachloronaphthalene, 1,2,3,4,5,6,7-heptachloronaphthalene, and octachloronaphthalene.

10. The method for detecting polychlorinated naphthalene in food according to claim 1, characterized in that, The food samples include animal-derived foods and plant-derived foods; the animal-derived foods are pork, chicken, fish, eggs, or milk; the plant-derived foods are grains, flour, or vegetables.

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