A method for detecting N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine in foam by liquid chromatography mass spectrometry

Abstract

The application belongs to the technical field of analysis and detection, and particularly relates to a liquid chromatography mass spectrometry detection method for N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine in foam. The detection method comprises: extracting and treating a foam sample to be detected, using acetonitrile-water mixture as an extraction solvent, filtering the extraction liquid through a filter membrane to obtain an extraction liquid; and detecting the extraction liquid by using a liquid chromatography mass spectrometry instrument. The analysis and test method has low detection limit, good precision, and high sample standard addition recovery rate, and meets the test requirements of N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine in foam. The target compound has a good linear relationship (r 2 >0.9998) in the range of 0.2-100 μg / L; the detection limit and the quantitative limit are both low, the detection limit is 0.14 μg / kg, the quantitative limit is 0.47 μg / kg, the relative standard deviation is less than 2.8%; and the sample standard addition recovery rate is 93.5%-109%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of analytical detection, and particularly relates to a liquid chromatography mass spectrometry detection method for N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine in foam. BACKGROUND

[0002] N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine (TMAEEA for short) is a reactive foaming catalyst, has low atomization, does not pollute PVC, is used for polyether polyurethane soft block foam, molded foam, semi-rigid foam and rigid foam, and is particularly suitable for automobile foam; the hydrogen on the hydroxyl group in the structure is very active, can react with isocyanate, and is difficult to volatilize in the system, is one of the environmentally friendly catalysts developed in recent years, and has been widely used in Japan, Europe and the United States and other countries, and has a large market demand. At present, the research on TMAEEA is focused on the synthesis and application fields, such as: (1) Ye Xiaoming, Wei Mengyi, Zhang Qi, Qian Chao, Chen Xinzh, et al. Synthesis Process Research of N,N,N,-Trimethyl-N,-hydroxyethyl Ethylenediamine; (2) Shi Lai-shun, Yang Zhongqiang, Zhao Ronghai, Ren Zhiying, Wang Tianyao, Ma Cunfei, Yu Xiaomeng, et al. Synthesis and On-line Infrared Spectroscopy of Hydroxyethyl Ethylenediamine / Formaldehyde Modified Lignin Amine Asphalt Emulsifier; (3) Zhang Qi, Zhang Chao, Zhang Hua, Ye Xiaoming, Chen Xinzh, Preparation Method of N,N,N'-Trimethyl-N'-hydroxyethyl Ethylenediamine; (4) Chen Hongxing, Zhao Zhuyuan, Zhu Rong, Gao Ku, Qin Siying, Jian Liangwu, et al. A device and method for co-production of pentamethyl diethylene triamine and trimethyl hydroxyethyl ethylenediamine.

[0003] Foaming catalysts remaining in products can volatilize into the air over time, thereby polluting the environment and affecting human health, for example, TMAEEA has stimulating effects on eyes, respiratory tracts and skin, and therefore, there are strict requirements for the residual amount of foaming catalysts in polyurethane foam plastics used in automobiles and household appliances. In the prior art, gas chromatographs, gas chromatography mass spectrometers and infrared spectroscopy are used for characterization of TMAEEA, and no reports about detection of the content of TMAEEA are found. Therefore, it is necessary to establish a method for determining the content of TMAEEA in foam products. SUMMARY

[0004] To solve the problem that the prior art cannot quickly and accurately detect TMAEEA in foam (especially polyurethane foam), the application provides a liquid chromatography mass spectrometry detection method for TMAEEA in foam.

[0005] The object of the application is achieved by the following technical scheme.

[0006] The liquid chromatography mass spectrometry detection method for TMAEEA in foam comprises the following steps:

[0007] (1) extracting the foam sample to be tested, the extraction solvent being acetonitrile-water mixture, the extraction liquid being filtered through a filter membrane to obtain an extraction liquid;

[0008] (2) detecting the extraction liquid by using a liquid chromatography tandem mass spectrometry (LCMS / MS);

[0009] In the detection process, an Agilent poroshell 120 SB-Aq column is used as the chromatographic column.

[0010] Preferably, the temperature of the extraction treatment is 23-70℃, and the time of the extraction treatment is 30-90 min.

[0011] More preferably, the temperature of the extraction treatment is 23℃, and the time of the extraction treatment is 60 min.

[0012] Preferably, the acetonitrile-water mixture has a volume percentage of acetonitrile of 0-80%.

[0013] Preferably, the extraction treatment is ultrasonic extraction, and the filter membrane is a 0.22μm filter membrane.

[0014] More preferably, the extraction treatment specifically comprises: cutting the foam to be tested into pieces with a size of no more than 2mm×2mm, weighing the sample into a sample bottle and adding an extraction solvent thereto, and then performing ultrasonic extraction.

[0015] Preferably, in the detection process of the liquid chromatography tandem mass spectrometry:

[0016] The liquid chromatography conditions are as follows: the Agilent poroshell 120 SB-Aq column is used; the injection volume is 1-20μL; the column temperature is 20-40℃; the mobile phase is 0-0.1% (v / v) formic acid aqueous solution (A) and acetonitrile (B); the flow rate is 0.2-0.6mL / min, the elution mode is isocratic elution, the volume ratio of the mobile phase is A:B=20-90:80-10, and the running time is 3-10min.

[0017] The mass spectrometry conditions are as follows: an atmospheric pressure jet stream electrospray ion source (AJS-ESI) is used; the ion source drying gas temperature is 200-300℃; the drying gas flow rate is 2-13L / min; the sheath gas temperature is 200-400℃; the sheath gas flow rate is 2-12L / min; the electrospray voltage is 30-60psi; the capillary voltage is 2000-6000V; positive ion scanning is used, and multiple reaction monitoring (MRM) is used.

[0018] More preferably, the liquid chromatography conditions are as follows: the chromatographic column is Agilent Poroshell 120 SB-Aq (3.0*150mm, 2.7um); the injection volume is 1ul; the column temperature is 40 DEG C; the mobile phase is 0.1% (v / v) formic acid aqueous solution (A) and acetonitrile (B); the flow rate is 0.4ml / min, the elution mode is isocratic elution, the mobile phase volume ratio is A:B = 80:20, and the running time is 3min.

[0019] More preferably, the mass spectrometry conditions are as follows: jet stream electrospray ion source (AJS-ESI); the ion source drying gas temperature is 350 DEG C; the drying gas flow rate is 5L / min; the sheath gas temperature is 300 DEG C; the sheath gas flow rate is 11L / min; the electrospray voltage is 50psi; the capillary voltage is 4000V; positive ion scanning, multiple reaction monitoring (MRM).

[0020] More preferably, the qualitative and quantitative ion pairs of the target compound TMAEEA are as follows: 147.1>102.1, 147.1>72.2, 147.1>58.2.

[0021] More preferably, the mass spectrometry parameters of the target compound TMAEEA are shown in Table 1:

[0022] Table 1 Mass spectrometry parameters of the target compound TMAEEA

[0023]

[0024] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0025] 1. The present application establishes a liquid chromatography-mass spectrometry method for determining TMAEEA in foam products, and through optimization of instrument analysis parameters, TMAEEA can be symmetrically chromatographically separated in 1.660min. Compared with other extraction solvents, when 20% (v / v) acetonitrile-water mixture is used as the extraction solvent, the matrix interference is smaller and the separation effect is optimal.

[0026] 2. The analysis test method of the present application has low detection limit, good precision and high sample spiking recovery rate, and meets the test requirements of TMAEEA in foam products. The target compound shows good linear relationship (r 2 >0.9998) in the range of 0.2-100ug / L; the detection limit and the quantitative limit are relatively low, the detection limit is 0.14ug / kg, the quantitative limit is 0.47ug / kg, and the relative standard deviation is less than 2.8%; the sample spiking recovery rate is 93.5%-109%. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1The peak shape of the standard substance under four columns, from top to bottom, represents the peak shape of the standard substance under Agilent Poroshell 120 SB-Aq (3.0*150mm, 2.7μm), Waters XTERRA Phenyl (2.1*100mm, 3.5μm), Agilent Eclipse XDB C18 (2.1*100mm, 1.8μm), and Agilent HILIC Plus (2.1*100mm, 3.5μm).

[0028] Figure 2 The peak shape of the standard substance under four columns, from top to bottom, represents the peak shape of the standard substance under Agilent Poroshell 120 SB-Aq (3.0*150mm, 2.7μm), Waters XTERRA Phenyl (2.1*100mm, 3.5μm), Agilent Eclipse XDB C18 (2.1*100mm, 1.8μm), and Agilent HILIC Plus (2.1*100mm, 3.5μm).

[0029] Figure 3 The response value comparison of different mobile phases (A) with the mobile phase (B) fixed as acetonitrile.

[0030] Figure 4 The chromatogram (a) and ion pair chromatogram (b) of the target compound TMAEEA under the optimal detection condition.

[0031] Figure 5 The influence of different ratios of extraction reagents on the extraction effect in Example 1, wherein 80% acetonitrile water, 50% acetonitrile water, 30% acetonitrile water, 20% acetonitrile water, and 10% acetonitrile water represent 80% (v / v) acetonitrile-water mixture, 50% (v / v) acetonitrile-water mixture, 30% (v / v) acetonitrile-water mixture, 20% (v / v) acetonitrile-water mixture, and 10% (v / v) acetonitrile-water mixture, respectively.

[0032] Figure 6 The influence of different extraction temperatures on the extraction efficiency in Example 2.

[0033] Figure 7 The influence of different extraction times on the extraction efficiency in Example 3. DETAILED DESCRIPTION

[0034] The present application will be further described in detail below in conjunction with the examples and the accompanying drawings, but the embodiments of the present application are not limited thereto. The raw materials involved in the present application can be directly purchased from the market. For the process parameters not specifically mentioned, the conventional techniques can be referred to.

[0035] Part of the instruments and reagents used in the experiment of the application are as follows:

[0036] Liquid chromatography tandem mass spectrometry (LCMS / MS)

[0037] Chromatographic column: Agilent Eclipse XDB C18 (2.1*100mm, 1.8um), Agilent HILIC Plus (2.1*100mm, 3.5um), Waters XTERRA Phenyl (2.1*100mm, 3.5um), Agilent poroshell 120SB-Aq (3.0*150mm, 2.7um)

[0038] Methanol, acetonitrile, TMAEEA are all analytical pure

[0039] The detection conditions of the application are optimized as follows:

[0040] I. Selection of chromatographic column

[0041] 1. Accurately weigh 10mg (accurate to 0.1mg) of standard substance (TMAEEA), dissolve with 10mL of pure water, and then dilute with pure water to 10ug / L of standard working solution.

[0042] 2. The standard working solution is determined by liquid chromatography tandem mass spectrometry, and the detection experiment is divided into 4 groups, respectively using Agilent Eclipse XDB C18 (2.1*100mm, 1.8um), Agilent HILIC Plus (2.1*100mm, 3.5um), Waters XTERRA Phenyl (2.1*100mm, 3.5um), Agilent poroshell 120SB-Aq (3.0*150mm, 2.7um) four kinds of chromatographic column.

[0043] The liquid chromatography conditions are

[0044] Injection volume: 1uL; column temperature: 40℃; mobile phase: 0.1%(v / v) formic acid aqueous solution (A) and acetonitrile (B); flow rate: 0.4mL / min, elution mode: isocratic elution, mobile phase volume ratio A:B=80:20, running time 3min;

[0045] The mass spectrometry conditions are

[0046] Agilent 1260 Infinity II LC / QQQ, Jet stream ESI source (AJS-ESI); Ion source dry gas temperature: 350℃; Dry gas flow rate: 5 L / min; Sheath gas temperature: 300℃; Sheath gas flow rate: 11 L / min; Electrospray voltage: 50 psi; Capillary voltage: 4000 V; Positive ion scan, multiple reaction monitoring (MRM), compound parameters are shown in Table 1.

[0047] 3. The detection results are shown in Table 2. Among the four kinds of chromatographic columns, the standard substance can normally peak in C18, AQ, HILIC and phenyl column, but from the peak height and peak shape, the peak shape of HILIC column is wide and tailing, the peak shape of C18 column is slightly tailing, the peak shape of phenyl column is wide and not sharp, and the peak shape of AQ column is sharp and symmetrical with the highest peak height. Therefore, the optimal chromatographic column is Agilent poroshell 120SB-Aq (3.0*150mm, 2.7μm). Figure 1 2 1. Accurately weigh 10 mg of standard substance (TMAEEA) (accurate to 0.1 mg), dissolve with 10 mL of pure water, and then dilute with pure water to 10 μg / L of standard working solution.

[0048] 2. The standard working solution was determined by liquid chromatography tandem mass spectrometry. The detection experiment was divided into two groups, using 0.1% (v / v) formic acid aqueous solution (A) and methanol (B), 0.1% (v / v) formic acid aqueous solution (A) and acetonitrile (B) as the mobile phase,

[0049] The liquid chromatography conditions are as follows:

[0050] Chromatographic column: Agilent poroshell 120SB-Aq (3.0*150mm, 2.7μm); injection volume: 1 μL; column temperature: 40℃; flow rate: 0.4 mL / min, elution mode: isocratic elution, mobile phase volume ratio A:B = 80:20, running time 3 min;

[0051] The mass spectrometry conditions are as follows:

[0052] Agilent 1260 Infinity II LC / QQQ, Jet stream ESI source (AJS-ESI); Ion source dry gas temperature: 350℃; Dry gas flow rate: 5 L / min; Sheath gas temperature: 300℃; Sheath gas flow rate: 11 L / min; Electrospray voltage: 50 psi; Capillary voltage: 4000 V; Positive ion scan, multiple reaction monitoring (MRM), compound parameters are shown in Table 1.

[0053] Agilent 1260 Infinity II LC / QQQ, Jet stream ESI source (AJS-ESI); Ion source dry gas temperature: 350℃; Dry gas flow rate: 5 L / min; Sheath gas temperature: 300℃; Sheath gas flow rate: 11 L / min; Electrospray voltage: 50 psi; Capillary voltage: 4000 V; Positive ion scan, multiple reaction monitoring (MRM), compound parameters are shown in Table 1.

[0054] Agilent 1260 Infinity II LC / QQQ, Jet stream ESI source (AJS-ESI); Ion source dry gas temperature: 350℃; Dry gas flow rate: 5 L / min; Sheath gas temperature: 300℃; Sheath gas flow rate: 11 L / min; Electrospray voltage: 50 psi; Capillary voltage: 4000 V; Positive ion scan, multiple reaction monitoring (MRM), compound parameters are shown in Table 1.

[0055] ​The results show that the peak shape of methanol and acetonitrile is symmetrical, but the response value is larger under the condition of acetonitrile, and there is no impurity peak interference near the retention time, so acetonitrile is selected as the organic phase.

[0056] 3. The standard working solution was determined by liquid chromatography tandem mass spectrometry, and the test was divided into 5 groups. The mobile phase was pure water (A) and acetonitrile (B), ammonium acetate (A) and acetonitrile (B), 0.01% (v / v) formic acid aqueous solution (A) and acetonitrile (B), 0.05% (v / v) formic acid aqueous solution (A) and acetonitrile (B), and 0.1% (v / v) formic acid aqueous solution (A) and acetonitrile (B), respectively. Other instrument working conditions were the same as step 2.

[0057] The response value results are shown in Table 1. Figure 3 The response value is the highest when acetonitrile and 0.1% (v / v) formic acid aqueous solution are used as the mobile phase, so 0-0.1% (v / v) formic acid aqueous solution-acetonitrile can be selected as the mobile phase to achieve the detection purpose. Figure 4 The chromatogram and ion pair chromatogram of the standard substance TMAEEA are shown in Figure 1, which are obtained under the detection scheme of 0.1% (v / v) formic acid aqueous solution (A) and acetonitrile (B) as the mobile phase.

[0058] Example 1

[0059] 1. A liquid chromatography mass spectrometry detection method for TMAEEA in foam, comprising the following steps:

[0060] (1) Take representative foam, cut it into pieces with a size not greater than 2mm x 2mm, accurately weigh 7 samples of 0.5g (accurate to 0.1mg), and put them into sample bottles and add 10mL of extraction solvent to each. After tightening the bottle cap, the sample bottles are placed in an ultrasonic cleaner and ultrasonically treated at 23°C for 60min. After cooling to room temperature, 1mL of the extraction solution is filtered through a 0.22μm filter membrane, and 7 extraction solutions are finally obtained according to different extraction solvents;

[0061] The 7 different extraction solvents are acetonitrile, 80% (v / v) acetonitrile-water mixture, 50% (v / v) acetonitrile-water mixture, 30% (v / v) acetonitrile-water mixture, 20% (v / v) acetonitrile-water mixture, 10% (v / v) acetonitrile-water mixture, and water.

[0062] (2) The obtained extraction solutions are determined by liquid chromatography tandem mass spectrometry, wherein

[0063] The liquid chromatography conditions are as follows:

[0064] Chromatographic column: Agilent poroshell 120SB-Aq (3.0*150mm, 2.7μm); injection volume: 1 μL; column temperature: 40℃; mobile phase: 0.1% (v / v) formic acid aqueous solution (A) and acetonitrile (B); flow rate: 0.4 mL / min, elution mode: isocratic elution, mobile phase volume ratio A:B = 80:20, running time 3 min;

[0065] Mass spectrometry conditions were

[0066] Jet stream electrospray ion source (AJS-ESI); ion source drying gas temperature: 350℃; drying gas flow rate: 5 L / min; sheath gas temperature: 300℃; sheath gas flow rate: 11 L / min; electrospray voltage: 50 psi; capillary voltage: 4000 V; positive ion scanning, multiple reaction monitoring (MRM), compound parameters as shown in Table 1.

[0067] 2, the detection results are shown in Figure 5 . Among the 7 extraction solvents, the extraction effect of 80% acetonitrile-water mixture is the highest; the result of pure acetonitrile is the lowest; from different acetonitrile ratios, the response value decreases with the decrease of acetonitrile volume ratio, and the result of pure water is similar to that of 20% acetonitrile-water mixture. Therefore, 80% acetonitrile-water mixture is the best sample extraction reagent.

[0068] Example 2

[0069] 1, in the experiment, 3 different foam products of green, white and blue on the market were selected for spiking test, 3 groups of experiments were designed for each foam sample, the extraction time was fixed at 60 min and the extraction solvent was 20% (v / v) acetonitrile-water mixture, and ultrasonic extraction was carried out at 23℃, 50℃ and 70℃ respectively. The preparation steps of the extract are referred to Example 1.

[0070] 2, the obtained extract was determined by liquid chromatography tandem mass spectrometry, and the instrument working conditions were the same as those in Example 1.

[0071] 3, the recovery rate results of this example are shown in Figure 6 , the abscissa is the extraction temperature (℃), and the ordinate is the recovery rate (%). From the results, the extraction efficiency of all samples decreases with the increase of ultrasonic temperature; among them, the extraction efficiency is the highest at 23℃, and is more than 90%. The reason for analysis may be that the higher the ultrasonic temperature, the greater the volatilization of the tested substance.

[0072] Example 3

[0073] 1. To study the effect of extraction time on the test results, three different foam products on the market were selected for spiking tests. Three groups of experiments were designed for each foam sample, with a fixed extraction temperature of 23°C and an extraction solvent of 20% (v / v) acetonitrile-water mixture. The extraction times were 30 min, 60 min, and 90 min, respectively. The extraction solution was prepared according to Example 1.

[0074] 2. The resulting extraction solution was measured using liquid chromatography tandem mass spectrometry, with the same instrument operating conditions as in Example 1.

[0075] 3. The recovery results of this example are shown in Figure 7 The horizontal axis represents the extraction time (min), and the vertical axis represents the recovery rate (%). Comparing the test results, it can be found that after 60 minutes of ultrasonic treatment, the maximum extraction efficiency can be achieved. The longer the ultrasonic time, the lower the extraction efficiency. Analysis shows that the sample has semi-volatility, so the recovery rate decreases slightly with the increase of extraction time. The shorter the ultrasonic time, the lower the extraction efficiency. Analysis shows that the foam sample has certain adsorption effect and is not completely ultrasonically extracted.

[0076] Example 4

[0077] A liquid chromatography mass spectrometry detection method for TMAEEA, comprising the following steps:

[0078] 1. Preparation method of extraction solution:

[0079] Take representative foam and cut it into pieces with a size not greater than 2 mm x 2 mm. Accurately weigh 0.5 g of the sample (accurate to 0.1 mg) and place it in a sample bottle. Add 10 mL of 20% (v / v) acetonitrile-water mixture to the bottle. Tighten the bottle cap and place the sample bottle in an ultrasonic cleaner at 23°C for 60 min. Cool to room temperature, take 1 mL of the extraction solution, filter it through a 0.22 μm filter membrane, and obtain the extraction solution.

[0080] 2. The instrument operating conditions are the same as in Example 1.

[0081] 3. Linear equation and detection limit:

[0082] Accurately weigh 10 mg of standard substance (TMAEEA) (accurate to 0.1 mg), dissolve it with pure water, and dilute to 10 mL in a volumetric flask to obtain a standard substance stock solution of 1000 mg / L. Store it in a 4°C refrigerator and protect it from light.

[0083] The standard stock solution is diluted with pure water to obtain a series of standard working solutions with concentrations of 0.2 μg / L, 1 μg / L, 1 μg / L, 5 μg / L, 10 μg / L, 20 μg / L, 50 μg / L and 100 μg / L. The series of standard working solutions are determined by using a liquid chromatography tandem mass spectrometry. A standard working curve is plotted with the mass concentration X (μg / L) as the abscissa and the response value Y as the ordinate. The linear equation and the correlation coefficient of the measured substance are shown in Table 2.

[0084] Table 2 Linear equation, correlation coefficient, detection limit and quantification limit

[0085]

[0086] As shown in the table, in the linear range of 0.2 μg / L to 100 μg / L, TMAEEA can exhibit a good linear relationship with a correlation coefficient of 0.9998. On this basis, the detection limit (LOD) and the quantification limit (LOQ) of the standard substance are determined by 3 times and 10 times the signal-to-noise ratio (S / N), and the detection limit of the method is 0.14 μg / kg, and the quantification limit is 0.47 μg / kg.

[0087] 4. Recovery rate and precision

[0088] The recovery rate experiment of the present study is performed by a blank matrix spiking experiment, and a sample without the measured TMAEEA is selected as the blank matrix. Three different spiking concentration levels (0.2 μg / L, 10 μg / L and 100 μg / L) are set. Each spiking level is tested in parallel for 6 times (n=6) to perform the precision experiment. Under the three spiking levels, the TMAEEA spiking recovery rate is 93.5% to 109%, and the recovery rate standard deviation is not greater than 2.8%, indicating that the testing method has high accuracy and can meet the testing requirements.

[0089] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement modes and shall be included in the protection scope of the present application.

Claims

1. A method for the detection of N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine in a foam by liquid chromatography mass spectrometry, characterized in that, The method comprises the following steps: (1) performing extraction treatment on the foam sample to be tested, using acetonitrile-water mixture as the extraction solvent, filtering the extraction liquid through a filter membrane to obtain an extraction liquid; the acetonitrile-water mixture has a volume percentage of acetonitrile of 0-80%; (2) detecting the extraction liquid by using a liquid chromatograph-mass spectrometer; In the detection process, an Agilent poroshell 120 SB-Aq column is used as the chromatographic column, 0-0.1% v / v formic acid aqueous solution and acetonitrile are used as the mobile phase, isocratic elution is used as the elution mode, and the volume ratio of the mobile phase is 0-0.1% v / v formic acid aqueous solution:acetonitrile = 20-90:80-10. The qualitative and quantitative ion pairs of the target compound N-methyl-N-(N,N-dimethylaminoethyl) ethanolamine are: 147.1>102.1, 147.1>72.2, and 147.1>58.

2.

2. The method of claim 1, wherein, The extraction treatment is performed at a temperature of 23-70°C and for a time of 30-90 min.

3. The method of claim 2, wherein, The extraction treatment is performed at a temperature of 23°C and for a time of 60 min.

4. The method of claim 1, wherein, The extraction treatment is ultrasonic extraction, and the filter membrane is a 0.22 μm filter membrane.

5. The method of claim 4, wherein, Specifically, the extraction treatment is performed as follows: the foam to be tested is cut into pieces with a size of no more than 2 mm*2 mm, a test sample is weighed and placed in a sample bottle, and extraction solvent is added to the sample bottle, followed by ultrasonic extraction.

6. The method of claim 1, wherein, In the detection process of the liquid chromatograph-mass spectrometer: The liquid chromatograph conditions are as follows: the Agilent poroshell 120 SB-Aq column is used; the injection amount is 1-20 μL; the column temperature is 20-40°C; the flow rate is 0.2-0.6 mL / min; and the running time is 3-10 min. The mass spectrometer conditions are as follows: a jet stream electrospray ion source is used; the ion source drying gas temperature is 200-300°C; the drying gas flow rate is 2-13 L / min; the sheath gas temperature is 200-400°C; the sheath gas flow rate is 2-12 L / min; the electrospray voltage is 30-60 psi; the capillary voltage is 2000-6000 V; positive ion scanning is used; and multiple reaction monitoring is used.

7. The method of claim 6, wherein, The liquid chromatograph conditions are as follows: the chromatographic column is an Agilent poroshell 120 SB-Aq 3.0*150 mm, 2.7 μm; the injection amount is 1 μL; the column temperature is 40°C; the mobile phase is 0.1% v / v formic acid aqueous solution and acetonitrile; the flow rate is 0.4 mL / min; the elution mode is isocratic elution; the volume ratio of the mobile phase is 0.1% v / v formic acid aqueous solution:acetonitrile = 80:20; and the running time is 3 min.

8. The method of claim 6, wherein, The mass spectrometer conditions are as follows: a jet stream electrospray ion source is used; the ion source drying gas temperature is 350°C; the drying gas flow rate is 5 L / min; the sheath gas temperature is 300°C; the sheath gas flow rate is 11 L / min; the electrospray voltage is 50 psi; the capillary voltage is 4000 V; positive ion scanning is used; and multiple reaction monitoring is used.

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