Method for detecting 2-amino-6-ethoxynaphthalene in consumer goods

Abstract

The invention provides a method for detecting 2-amino-6-ethoxynaphthalene in consumer goods. The method comprises the following steps: sampling; adding a first volume of methanol solution into the to-be-detected sample, and carrying out ultrasonic extraction at a first specified temperature for a first specified time to obtain an extract liquid; filtering the extracting solution to obtain a loading test solution; and detecting the content of the 2-amino-6-ethoxynaphthalene in the loading test solution by using a gas chromatograph-mass spectrometer. According to the method, the 2-amino-6-ethoxynaphthalene in the consumer goods is detected by adopting a gas chromatography-mass spectrometer, and the detection limit can reach 2mg / kg, namely 0.0002%, which is far lower than the requirement specified by REACH (Region Emission for Authority of Consumption) regulations (EC) 2020 / 2081.

Description

Technical Field

[0001] The present application relates to the field of consumer product testing, and in particular to a method for testing 2-amino-6-ethoxynaphthalene in consumer products. Background Art

[0002] 2-amino-6-ethoxynaphthalene, CAS number: 293733-21-8, structural formula: Figure 2 As shown, it is a white crystalline powder, soluble in organic solvents such as ethanol, ether and benzene, insoluble in water, and has a special ammonia smell. It is a fluorescent dye. After consumer products use dyes containing 2-amino-6-ethoxynaphthalene, they may be absorbed by the skin during long-term contact with the human body and spread in the human body, causing skin allergies, respiratory diseases or other poisoning reactions, and even inducing cancer.

[0003] REACH Regulation (EC) 2020 / 2081 strictly limits the use of 2-amino-6-ethoxynaphthalene, and its concentration shall not exceed 0.0005%. The harm of 2-amino-6-ethoxynaphthalene to the environment and human body cannot be ignored. With the improvement of people's living standards, the demand for consumer goods is increasing. At present, the detection of 2-amino-6-ethoxynaphthalene in consumer goods is still in a blank stage. It is imperative to establish an efficient and reliable detection technology for the content of 2-amino-6-ethoxynaphthalene in consumer goods. Summary of the invention

[0004] In view of the above problems, the present application is proposed to provide a method for detecting 2-amino-6-ethoxynaphthalene in a consumer product that overcomes the above problems or at least partially solves the above problems, comprising:

[0005] A method for detecting 2-amino-6-ethoxynaphthalene in consumer products comprises the steps of:

[0006] sampling;

[0007] Adding a first volume of methanol solution to the sample to be tested, and ultrasonically extracting the sample at a first specified temperature for a first specified time to obtain an extract;

[0008] Filtering the extract to obtain a test solution;

[0009] The content of 2-amino-6-ethoxynaphthalene in the upper machine test solution is detected by gas chromatography-mass spectrometry.

[0010] Furthermore, the sampling step comprises:

[0011] Weigh 1 g ± 0.1 mg of the sample to be tested into a test tube.

[0012] Furthermore, the first volume is 10 ml.

[0013] Furthermore, the first designated temperature is 65°C-75°C.

[0014] Furthermore, the first designated time is 55 minutes to 65 minutes.

[0015] Furthermore, the step of filtering the extract to obtain a test solution for the machine includes:

[0016] The extract is shaken and filtered through a filter membrane;

[0017] Take 1 mL of the filtrate into a sample injection vial to obtain the test solution for the machine.

[0018] Furthermore, the gas phase parameters of the gas chromatography-mass spectrometry instrument are:

[0019] Chromatographic column: DB-35MS, 30m×0.25μm film thickness×0.25mm inner diameter;

[0020] Carrier gas type: helium;

[0021] Carrier gas flow rate: 1.0 mL / min;

[0022] Injection volume: 1.0 μL;

[0023] Diversion mode: no diversion;

[0024] Inlet temperature: 220°C;

[0025] Column oven temperature program: initial temperature 60°C and maintain for 1 min, increase the temperature to 230°C at 40°C / min, and then increase the temperature to 310°C at 30°C / min and maintain for 3 min.

[0026] Furthermore, the mass spectrometry parameters of the gas chromatography-mass spectrometry instrument are:

[0027] Mass spectrometer interface temperature: 310°C;

[0028] Ion source temperature: 230°C;

[0029] Quadrupole temperature: 150℃;

[0030] Mass spectrometry scanning modes: selected ion scanning and full scan;

[0031] Characteristic ions of the target substance: quantitative ion 187; qualitative ions 158, 130.

[0032] Further, the step of detecting the content of 2-amino-6-ethoxynaphthalene in the upper machine test solution by gas chromatography-mass spectrometry includes qualitative analysis;

[0033] The qualitative analysis includes:

[0034] The sample to be tested is measured under the same experimental conditions. If the retention time of the detected chromatographic peak is consistent with that of the standard substance, and the characteristic ions of the target compound appear in the mass spectrum of the sample after background subtraction, and the abundance ratio of the characteristic ions is consistent with that of the standard substance, it is determined that the sample to be tested contains 2-amino-6-ethoxynaphthalene.

[0035] Further, the step of detecting the content of 2-amino-6-ethoxynaphthalene in the upper test solution by gas chromatography-mass spectrometry includes quantitative analysis;

[0036] The quantitative analysis includes:

[0037] The 2-amino-6-ethoxynaphthalene standard substance was prepared into a standard stock solution with a concentration of 1000 mg / L using a methanol solution;

[0038] The standard stock solution of 2-amino-6-ethoxynaphthalene was diluted with methanol solution to obtain standard working solutions of 0.20 mg / L, 0.50 mg / L, 1.00 mg / L, 2.00 mg / L and 5.00 mg / L;

[0039] The calibration curve has at least 5 concentration points. The standard substance test solution and the sample test solution are subjected to instrumental analysis under the same conditions. Then, a calibration curve is made based on the peak area corresponding to the concentration of the standard substance test solution. The regression equation and the correlation coefficient are obtained. The content of 2-amino-6-ethoxynaphthalene is calculated according to the concentration of 2-amino-6-ethoxynaphthalene. If the concentration of 2-amino-6-ethoxynaphthalene in the sample test solution exceeds the range of the calibration curve, dilution and reanalysis are required.

[0040] The calculation formula is:

[0041]

[0042] In the formula, C 2-氨基-6-乙氧基萘 is the mass concentration of the sample 2-amino-6-ethoxynaphthalene, in mg / kg; C C is the concentration of 2-amino-6-ethoxynaphthalene read on the calibration curve, in mg / L; V is the final effective volume of the extraction solvent, in mL; m is the weight of the sample used for determination, in g; DF is the dilution factor.

[0043] This application has the following advantages:

[0044] In the embodiments of the present application, relative to the current detection of 2-amino-6-ethoxynaphthalene in consumer products in the prior art, which is still in a blank stage, the present application provides a solution for detecting 2-amino-6-ethoxynaphthalene in consumer products using a gas chromatograph-mass spectrometer, specifically: sampling; adding a first volume of methanol solution to the sample to be tested, and ultrasonically extracting the first specified time at a first specified temperature to obtain an extract; filtering the extract to obtain a machine test solution; and detecting the content of 2-amino-6-ethoxynaphthalene in the machine test solution by a gas chromatograph-mass spectrometer. The present invention uses a gas chromatograph-mass spectrometer to detect 2-amino-6-ethoxynaphthalene in consumer products, and the detection limit can reach 2mg / kg, i.e. 0.0002%, which is much lower than the requirements specified in REACH Regulation (EC) 2020 / 2081. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the description of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0046] Figure 1 It is a flow chart of the steps of a method for detecting 2-amino-6-ethoxynaphthalene in consumer products provided in one embodiment of the present application;

[0047] Figure 2 is the structural formula of 2-amino-6-ethoxynaphthalene provided in one embodiment of the present application;

[0048] Figure 3 This is a chromatogram of 2-amino-6-ethoxynaphthalene provided in one embodiment of the present application;

[0049] Figure 4 This is a characteristic ion mass spectrum of 2-amino-6-ethoxynaphthalene provided in one embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the objects, features and advantages of the present application more obvious and understandable, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0051] The inventors found through analysis of the prior art that after a certain pretreatment of the sample to be tested, by studying the instrument parameters and improving the instrument method, the content of 2-amino-6-ethoxynaphthalene in consumer products can be determined using a gas chromatography-mass spectrometer.

[0052] Reference Figure 1 , showing a method for detecting 2-amino-6-ethoxynaphthalene in a consumer product provided by an embodiment of the present application;

[0053] The method comprises:

[0054] S110, sampling;

[0055] S120, adding a first volume of methanol solution to the sample to be tested, and ultrasonically extracting the sample at a first specified temperature for a first specified time to obtain an extract;

[0056] S130, filtering the extract to obtain a test solution;

[0057] S140, detecting the content of 2-amino-6-ethoxynaphthalene in the upper machine test solution by gas chromatography-mass spectrometry.

[0058] In the embodiments of the present application, relative to the current detection of 2-amino-6-ethoxynaphthalene in consumer products in the prior art, which is still in a blank stage, the present application provides a solution for detecting 2-amino-6-ethoxynaphthalene in consumer products using a gas chromatograph-mass spectrometer, specifically: sampling; adding a first volume of methanol solution to the sample to be tested, and ultrasonically extracting the first specified time at a first specified temperature to obtain an extract; filtering the extract to obtain a machine test solution; and detecting the content of 2-amino-6-ethoxynaphthalene in the machine test solution by a gas chromatograph-mass spectrometer. The present invention uses a gas chromatograph-mass spectrometer to detect 2-amino-6-ethoxynaphthalene in consumer products, and the detection limit can reach 2mg / kg, i.e. 0.0002%, which is much lower than the requirements specified in REACH Regulation (EC) 2020 / 2081.

[0059] Next, the detection method of 2-amino-6-ethoxynaphthalene in a consumer product in this exemplary embodiment will be further described.

[0060] As described in step S110, sampling is performed.

[0061] In an embodiment of the present invention, the specific process of “sampling” in step S110 may be further explained in combination with the following description.

[0062] As described in the following steps, weigh 1 g ± 0.1 mg of the sample to be tested into a test tube.

[0063] It should be noted that sampling is generally one of the important steps to extract a small amount of target substance from the target object for testing. It is one of the effective ways to obtain the target object for testing and obtain various data without affecting the main properties of the target object. The amount of the extracted object must be sufficient for 3-5 tests. The sampling area selection process for the object to be tested is required to be random.

[0064] As an example, the sample to be tested is cut into small pieces of 3 mm×3 mm, mixed evenly, and set aside. 1 g of the sample to be tested (accurate to 0.1 mg) is weighed into a glass test tube.

[0065] As described in step S120, a first volume of methanol solution is added to the sample to be tested, and ultrasonic extraction is performed at a first specified temperature for a first specified time to obtain an extract.

[0066] It should be noted that this step is to pretreat the sample to be tested. Pretreatment is generally a step of removing impurities and purifying the target object before carrying out effective processes. In some special experiments, the pretreatment step also includes the purpose of changing the properties of the substance. In this embodiment, it is preferred to use ultrasound to pretreat the sample to be tested.

[0067] In this embodiment, the first volume is 10 ml; the first designated temperature is 65° C.-75° C.; and the first designated time is 55 min-65 min.

[0068] As an example, 10 ml of methanol solution was added and extracted in ultrasound at (70±5)°C for (60±5) min. Methanol was used as the extraction solvent and ultrasound was used as the extraction instrument. 2-amino-6-ethoxynaphthalene had good solubility in methanol, ensuring that the target compound could be effectively transferred from the sample to the methanol solvent, thereby improving the efficiency and accuracy of the extraction. Methanol as a solvent had good compatibility with the gas chromatography-mass spectrometry instrument, improving the accuracy and reliability of the analysis.

[0069] As described in step S130, the extract is filtered to obtain a test solution for the machine.

[0070] In an embodiment of the present invention, the specific process of "filtering the extract to obtain a test solution for the machine" in step S130 can be further explained in combination with the following description.

[0071] As described in the following steps, the extract is shaken and filtered through a filter membrane;

[0072] As described in the following steps, 1 mL of the filtrate was taken into a sample injection vial to obtain the test solution for the machine.

[0073] As an example, after shaking well, filter with a 0.45μm filter membrane, and take 1mL of sample solution into a sampling vial. Filtering can improve the purity of the test solution on the machine, avoid the influence of plastic impurities, and improve the detection accuracy.

[0074] As described in step S140, the content of 2-amino-6-ethoxynaphthalene in the upper machine test solution is detected by gas chromatography-mass spectrometry.

[0075] This application uses gas chromatography-mass spectrometry GC-MS (Agilent 8860-5977B) for qualitative and quantitative analysis.

[0076] The gas phase parameters of the gas chromatography-mass spectrometry instrument are:

[0077] Chromatographic column: DB-35MS (30m×0.25μm film thickness×0.25mm inner diameter);

[0078] Carrier gas type: helium;

[0079] Carrier gas flow rate: 1.0 mL / min;

[0080] Injection volume: 1.0 μL;

[0081] Diversion mode: no diversion;

[0082] Inlet temperature: 220°C;

[0083] Column oven temperature program: initial temperature 60°C (maintained for 1 min), increased to 230°C at 40°C / min, and then increased to 310°C at 30°C / min (maintained for 3 min).

[0084] The mass spectrometry parameters of the gas chromatography-mass spectrometer are:

[0085] Mass spectrometer interface temperature: 310°C;

[0086] Ion source temperature: 230°C;

[0087] Quadrupole temperature: 150℃;

[0088] Mass spectrometry scanning modes: selected ion scanning and full scan;

[0089] The characteristic ions of the target are shown in Table 1 below:

[0090]

[0091] Table 1

[0092] In one embodiment of the present invention, the specific process of "detecting the content of 2-amino-6-ethoxynaphthalene in the upper test solution by gas chromatography-mass spectrometry" in step S140 can be further explained in combination with the following description.

[0093] As described in the following steps, a qualitative analysis is included; the qualitative analysis includes:

[0094] The sample to be tested is measured under the same experimental conditions. If the retention time of the detected chromatographic peak is consistent with that of the standard substance, and the characteristic ions of the target compound appear in the mass spectrum of the sample after background subtraction, and the abundance ratio of the characteristic ions is consistent with that of the standard substance, it is determined that the sample to be tested contains 2-amino-6-ethoxynaphthalene.

[0095] Qualitative requirements (permissible deviation of relative percentage of mass spectrometry characteristic ions) are shown in Table 2 below:

[0096]

[0097] Table 2

[0098] As described in the following steps, quantitative analysis is included; the quantitative analysis includes:

[0099] The 2-amino-6-ethoxynaphthalene standard substance was prepared into a standard stock solution with a concentration of 1000 mg / L using a methanol solution;

[0100] The standard stock solution of 2-amino-6-ethoxynaphthalene was diluted with methanol solution to obtain standard working solutions of 0.20 mg / L, 0.50 mg / L, 1.00 mg / L, 2.00 mg / L and 5.00 mg / L;

[0101] The calibration curve has at least 5 concentration points. The standard substance test solution and the sample test solution are subjected to instrumental analysis under the same conditions. Then, a calibration curve is made based on the peak area corresponding to the concentration of the standard substance test solution. The regression equation and the correlation coefficient are obtained. The content of 2-amino-6-ethoxynaphthalene is calculated according to the concentration of 2-amino-6-ethoxynaphthalene. If the concentration of 2-amino-6-ethoxynaphthalene in the sample test solution exceeds the range of the calibration curve, dilution and reanalysis are required.

[0102] The calculation formula is:

[0103]

[0104] In the formula, C 2-氨基-6-乙氧基萘 is the mass concentration of the sample 2-amino-6-ethoxynaphthalene, in mg / kg; C C is the concentration of 2-amino-6-ethoxynaphthalene read on the calibration curve, in mg / L; V is the final effective volume of the extraction solvent, in mL; m is the weight of the sample used for determination, in g; DF is the dilution factor.

[0105] The following are embodiments of the present invention:

[0106] The spiked test was conducted on red cloth, cotton pad, black leather, and 2-amino-6-ethoxynaphthalene in white ink samples, as follows:

[0107] Analysis steps:

[0108] Prepare the following samples: red cloth pieces cut to 3mm×3mm, cotton pads, black leather, and tattoo ink samples, mix well and set aside. Weigh 1g of sample (accurate to 0.1mg) into test tubes, add appropriate volumes of 2-amino-6-ethoxynaphthalene standard solution to make the final sample solution spiked with concentrations of 0.2mg / L, 1.0mg / L and 5.0mg / L, respectively, then add 10mL of methanol solution, extract in ultrasonic at (70±2)℃ for (60±5)min, shake well, filter with 0.45μm filter membrane, and collect 1mL of sample solution for GC-MS analysis.

[0109] Set the instrument parameters:

[0110] Instrument type: GC-MS (Agilent 8860-5977B); chromatographic column: DB-35MS (30m×0.25μm film thickness×0.25mm inner diameter); carrier gas type: helium; carrier gas flow rate: 1.0mL / min; injection volume: 1.0μL; split mode: non-split; injection port temperature: 220℃; column oven temperature program: starting temperature 60℃ (maintained for 1min), heated to 230℃ at 40℃ / min, and then heated to 310℃ at 30℃ / min (maintained for 3min); mass spectrometer interface temperature: 310℃; ion source temperature: 230℃; quadrupole temperature: 150℃; mass spectrometer scanning mode: selected ion scanning and full scan; characteristic ions of target: qualitative ions: 187, quantitative ions: 158, 130.

[0111] After the above analysis experiment is completed, a peak consistent with the retention time of the characteristic ion of the target compound appears in the retention time window, and the characteristic ions of the target compound appear in the sample mass spectrum after background subtraction, and the abundance ratio of the characteristic ions is consistent with that of the standard substance. The retention time of the target compound 2-amino-6-ethoxynaphthalene is 7.3min (i.e. 7 minutes and 18 seconds), and the retention time and abundance tolerances of all analyzed samples are within the allowable deviation range.

[0112] Follow the steps below to prepare the standard solution:

[0113] Pipette 0.2mL, 0.5mL10mg / L 2-amino-6-ethoxynaphthalene standard solution and 0.1mL, 0.2mL, 0.5mL100mg / L 2-amino-6-ethoxynaphthalene standard solution into 5 different 10mL volumetric flasks, dilute to the scale with methanol solution, and the concentration of the obtained standard curve solution series is: 0.2mg / L, 0.5mg / L, 1mg / L, 2mg / L, 5mg / L. Collect 1mL of each standard solution for GC-MS analysis. Figure 3 , is a chromatogram of 2-amino-6-ethoxynaphthalene provided in an embodiment of the present application; refer to Figure 4 , is a characteristic ion mass spectrum of 2-amino-6-ethoxynaphthalene provided in one embodiment of the present application.

[0114] The test results are shown in Table 3 below:

[0115]

[0116] Table 3

[0117] It can be seen from Table 3 that the detection limit of this embodiment is 2 mg / kg, which is far lower than the requirements specified in REACH Regulation (EC) 2020 / 2081, and the recovery rate is 92%-102%, which is relatively high. This shows that the present invention uses methanol as the extraction solvent, uses ultrasound as the extraction instrument, and extracts in ultrasound at (70±5)°C for (60±5) min. The target compound and impurities can be effectively separated by independently exploring and optimizing instrument parameters such as the gas chromatography-mass spectrometer separation heating program and data acquisition parameters.

[0118] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present application.

[0119] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0120] The above is a detailed introduction to the detection method of 2-amino-6-ethoxynaphthalene in a consumer product provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for a person skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for detecting 2-amino-6-ethoxynaphthalene in consumer products, characterized in that: Includes steps: sampling; Adding a first volume of methanol solution to the sample to be tested, and ultrasonically extracting the sample at a first specified temperature for a first specified time to obtain an extract; Filtering the extract to obtain a test solution; The content of 2-amino-6-ethoxynaphthalene in the upper machine test solution is detected by gas chromatography-mass spectrometry.

2. The detection method according to claim 1, characterized in that: The sampling step comprises: Weigh 1 g ± 0.1 mg of the sample to be tested into a test tube.

3. The detection method according to claim 1, characterized in that: The first volume was 10 ml.

4. The detection method according to claim 1, characterized in that: The first designated temperature is 65°C-75°C.

5. The detection method according to claim 1, characterized in that: The first designated time is 55 minutes to 65 minutes.

6. The detection method according to claim 1, characterized in that: The step of filtering the extract to obtain a test solution for the machine comprises: The extract is shaken and filtered through a filter membrane; Take 1 mL of the filtrate into a sample injection vial to obtain the test solution for the machine.

7. The detection method according to claim 1, characterized in that: The gas phase parameters of the gas chromatography-mass spectrometry instrument are: Chromatographic column: DB-35MS, 30m×0.25μm film thickness×0.25mm inner diameter; Carrier gas type: helium; Carrier gas flow rate: 1.0 mL / min; Injection volume: 1.0 μL; Diversion mode: no diversion; Inlet temperature: 220°C; Column oven temperature program: initial temperature 60°C and maintain for 1 min, increase the temperature to 230°C at 40°C / min, and then increase the temperature to 310°C at 30°C / min and maintain for 3 min.

8. The detection method according to claim 1, characterized in that: The mass spectrometry parameters of the gas chromatography-mass spectrometer are: Mass spectrometer interface temperature: 310°C; Ion source temperature: 230°C; Quadrupole temperature: 150℃; Mass spectrometry scanning modes: selected ion scanning and full scan; Characteristic ions of the target substance: quantitative ion 187; qualitative ions 158, 130.

9. The detection method according to claim 1, characterized in that: The step of detecting the content of 2-amino-6-ethoxynaphthalene in the upper test solution by gas chromatography-mass spectrometry comprises qualitative analysis; The qualitative analysis includes: The sample to be tested is measured under the same experimental conditions. If the retention time of the detected chromatographic peak is consistent with that of the standard substance, and the characteristic ions of the target compound appear in the mass spectrum of the sample after background subtraction, and the abundance ratio of the characteristic ions is consistent with that of the standard substance, it is determined that the sample to be tested contains 2-amino-6-ethoxynaphthalene.

10. The detection method according to claim 9, characterized in that: The step of detecting the content of 2-amino-6-ethoxynaphthalene in the upper test solution by gas chromatography-mass spectrometry comprises quantitative analysis; The quantitative analysis includes: The 2-amino-6-ethoxynaphthalene standard substance was prepared into a standard stock solution with a concentration of 1000 mg / L using a methanol solution; The standard stock solution of 2-amino-6-ethoxynaphthalene was diluted with methanol solution to obtain standard working solutions of 0.20 mg / L, 0.50 mg / L, 1.00 mg / L, 2.00 mg / L and 5.00 mg / L; The calibration curve has at least 5 concentration points. The standard substance test solution and the sample test solution are subjected to instrumental analysis under the same conditions. Then, a calibration curve is made based on the peak area corresponding to the concentration of the standard substance test solution. The regression equation and the correlation coefficient are obtained. The content of 2-amino-6-ethoxynaphthalene is calculated according to the concentration of 2-amino-6-ethoxynaphthalene. If the concentration of 2-amino-6-ethoxynaphthalene in the sample test solution exceeds the range of the calibration curve, dilution and reanalysis are required. The calculation formula is: In the formula, C 2-氨基-6-乙氧基萘 is the mass concentration of the sample 2-amino-6-ethoxynaphthalene, in mg / kg; C C is the concentration of 2-amino-6-ethoxynaphthalene read on the calibration curve, in mg / L; V is the final effective volume of the extraction solvent, in mL; m is the weight of the sample used for determination, in g; DF is the dilution factor.

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