A method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry

Abstract

The invention discloses a method for detecting N-cyclohexyl toluenesulfonamide in coatings by gas chromatography-mass spectrometry, and belongs to the technical field of quality detection. The invention optimizes the instrumental analysis parameters to obtain a chromatographic separation peak of N-cyclohexyl toluenesulfonamide in a relatively short time. The analytical test method of the invention has a low detection limit, good precision, and a high sample spike recovery rate, which meets the test requirements of N-cyclohexyl toluenesulfonamide in coating products; the correlation coefficient reaches 0.9996 within the concentration range of 0.1-10.0 mg / L; the detection limit and quantitative limit are both low, only 0.0144 mg / L and 0.4316 mg / L, respectively, and RSD% <2.1%; the average sample spike recovery rate is 97.6%-104.2%.

Description

Technical Field

[0001] The invention relates to the technical field of quality detection, and in particular to a method for detecting N-cyclohexyl-p-toluenesulfonamide in a coating by using gas chromatography-mass spectrometry. Background Art

[0002] Plasticizers, also known as plasticizers, are an important class of chemical product additives, and are widely used in materials such as paints, coatings, adhesives, plastic products, cement, gypsum, cosmetics, and cleaning agents. They can strengthen the plasticity of resin molecules by weakening the secondary bonds between resin molecules, enhancing the mobility of molecular bonds, and reducing the crystallinity of resin molecules, thereby enhancing the flexibility of resins and making them easier to process. Among them, N-cyclohexyl-p-toluenesulfonamide, as a sulfonamide plasticizer, can not only improve the processing performance of products, enhance the softness, expansion, impact resistance, and wear resistance of products, but also has a high refractive index, which can increase the brightness of coatings, paints, and many resins, and produce bright crystals and shining luster that general plasticizers cannot produce. However, plasticizers can also cause harm to human health during use. Di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and benzyl butyl phthalate (BBP) have been included in the first list of substances of very high concern (SVHC). N-butylbenzenesulfonamide has been confirmed to have neurotoxicity that causes spastic myelopathy in rabbits. N-cyclohexyl toluenesulfonamide has also been classified and graded as causing serious eye damage / eye irritation, which means that N-cyclohexyl toluenesulfonamide will have an impact on human health. Based on safety considerations, it is very necessary to establish a suitable method to determine the content of N-cyclohexyl toluenesulfonamide in products.

[0003] At present, the research on the detection of plasticizers mainly focuses on the detection of phthalates and some sulfonamide plasticizers, such as "Determination of the content of 6 phthalates plasticizers in plastic express packaging by ultrasonic extraction-gas chromatography-mass spectrometry" and "Determination of the content of o- and p-toluenesulfonamide in sodium saccharin by gas chromatography"; for the research on N-cyclohexyl-p-toluenesulfonamide, more attention is paid to its toxicity, such as "A neurotoxic plasticizer that causes spastic myelopathy in rabbits"; Chinese patent CN106366652A, "New preparation technology and application research of high friction and anti-wear vehicle dynamic seals" and "Study on the interface bonding effect of polyamide 6 / glass fiber composite materials" all introduce the application of N-cyclohexyl-p-toluenesulfonamide. At present, there are few reports on the detection of N-cyclohexyl-p-toluenesulfonamide residues in products.

[0004] Therefore, according to the physicochemical properties and characteristics of N-cyclohexyl-p-toluenesulfonamide, developing a method for detecting the content of N-cyclohexyl-p-toluenesulfonamide in products is of great significance for the detection of this substance. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry. The method is simple and efficient, has high accuracy and sensitivity, and can meet the testing requirements of N-cyclohexyl-p-toluenesulfonamide in coating products.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for detecting N-cyclohexyl-p-toluenesulfonamide in a coating by gas chromatography-mass spectrometry, the method comprising the following steps:

[0007] S1. Prepare a standard solution containing N-cyclohexyl-p-toluenesulfonamide using organic solvent A;

[0008] S2, using gas chromatography-mass spectrometry to detect the standard solution in step S1 and draw a standard curve;

[0009] S3, using organic solvent B to ultrasonically extract N-cyclohexyl-p-toluenesulfonamide in the coating sample, and preparing a sample solution to be tested;

[0010] S4. Detecting the sample solution of step S3 using a gas chromatography-mass spectrometer, and calculating the content of N-cyclohexyl-p-toluenesulfonamide in the sample solution according to the detection result and the standard curve drawn in step S2.

[0011] The inventors of the present invention have found through a large number of experiments that according to the above method, the quantitative ion 210 and the qualitative ion 155 in the standard solution of the coating sample can be detected by gas chromatography-mass spectrometry, and the content of N-cyclohexyl-p-toluenesulfonamide in the coating can be quickly detected, and the detection result has high accuracy, and the detection limit and quantitative limit are low, which are only 0.0144 mg / L and 0.4316 mg / L respectively.

[0012] The above-mentioned method can be widely used in the detection of the content of N-cyclohexyl-p-toluenesulfonamide, and is particularly suitable for the detection of N-cyclohexyl-p-toluenesulfonamide in coating products. The method of the present invention fills the gap in the current field of N-cyclohexyl-p-toluenesulfonamide content determination, and provides technical and data support for the safe use of coatings and manufacturers' quality control of products.

[0013] As a preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry of the present invention, in steps S2 and S4, the chromatographic conditions are as follows:

[0014] Chromatographic column: Agilent HP-5ms; injection port temperature: 290°C, injection mode: splitless, column flow rate: 1.2 mL / min, heating program: initial temperature 120°C, hold for 0 min, increase the temperature to 250°C at 15°C / min, hold for 1 min;

[0015] The mass spectrometry conditions were as follows:

[0016] Electron bombardment ion source; ionization energy: 70ev, ion source temperature: 230℃, quadrupole temperature: 150℃, solvent delay: 3min, acquisition mode: SIM.

[0017] The function of the injection port in a gas chromatograph is to vaporize the sample and introduce it into the gas phase system. Therefore, the temperature of the injection port must be based on the basic principle of ensuring the effective vaporization of the liquid analyte. Too low a temperature will lead to incomplete sample vaporization and broaden the sample peak, but too high a temperature will easily cause the sample to decompose; the ion source temperature in a mass spectrometer refers to the temperature of the atomizing gas nitrogen. The higher the ion source temperature, the higher the ionization efficiency, but setting the temperature too high will damage the life of the ion source heating module and increase the cost of use. The inventors have found through a large number of experiments that the selection of the above-mentioned chromatographic and mass spectrometric conditions can make the detection results more accurate.

[0018] As a more preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry of the present invention, in steps S2 and S4, the chromatographic conditions are as follows:

[0019] The chromatographic conditions were as follows:

[0020] Chromatographic column: Agilent HP-5ms; injection port temperature: 250-300°C, injection mode: splitless, column flow rate: 0.8-1.6 mL / min, heating program: initial temperature 120°C, hold for 0 min, increase the temperature to 250°C at 15°C / min, hold for 1 min;

[0021] The mass spectrometry conditions were as follows:

[0022] Electron bombardment ion source; ionization energy: 70ev, ion source temperature: 220-250℃, quadrupole temperature: 140-160℃, solvent delay: 3-6min, acquisition mode: SIM.

[0023] As a preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in a coating by gas chromatography-mass spectrometry of the present invention, in step S3, the mass volume ratio of the coating sample to the organic solvent B is 1 g:(5-20) mL; the authors found through a large number of experiments that the mass volume ratio of the coating sample to methanol has an important influence on the extraction effect of N-cyclohexyl-p-toluenesulfonamide in the coating sample. When the mass volume ratio of the coating sample to methanol is within the above range, the extraction effect of N-cyclohexyl-p-toluenesulfonamide in the final coating sample can be better, and the detection result of the content of N-cyclohexyl-p-toluenesulfonamide is more accurate.

[0024] As a more preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in a coating by gas chromatography-mass spectrometry of the present invention, the mass-to-volume ratio of the coating sample to methanol is 1 g:10 mL. The inventors have found through a large number of experiments that when the mass-to-volume ratio of the coating sample to methanol is 1 g:10 mL, the extraction effect can be better, thereby making the final detection result more accurate.

[0025] As a preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry of the present invention, step S3 comprises at least one of the following conditions:

[0026] (a) The conditions of ultrasonic extraction are as follows: temperature is 25-60°C, time is 30-120 min;

[0027] (b) filtering the extract through a filter membrane with a pore size of 0.45 μm;

[0028] (d) The organic solvent B comprises at least one of methanol, toluene and acetone.

[0029] As a more preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in a coating by gas chromatography-mass spectrometry of the present invention, the conditions for ultrasonic extraction are as follows: the temperature is 45°C and the ultrasonic extraction time is 60 min; the increase in the extraction temperature can accelerate the movement of the molecules of the sample to be tested, increase the concentration of the analyte in the liquid phase, and thus increase the extraction amount, but too high an extraction temperature will cause the solvent or solute with a lower boiling point to volatilize, reduce the distribution coefficient, and be unfavorable for the extraction equilibrium; if the extraction time is too short, the extraction cannot reach saturation, and if the extraction time is too long, it not only affects the work efficiency, but may also affect the extraction equilibrium; the inventors have found through a large number of experiments that when the extraction temperature is 45°C and the extraction time is 60 min, not only a higher extraction rate can be achieved, but also time cost can be saved.

[0030] As a preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry of the present invention, the specific steps of the sample pretreatment in step S1 are: weighing 1.0g±0.1g (accurate to 0.1mg) of a representative coating sample, placing it in a 20mL sample bottle, and adding 10mL of methanol thereto; after tightening the bottle cap, ultrasonically extracting the sample bottle at a temperature of 45°C and an extraction time of 60min, letting it stand for 5min after extraction, taking the extraction solution and filtering the sample with a 0.45μm filter membrane, placing it in an injection vial, and performing qualitative and quantitative tests using a gas chromatography-mass spectrometer.

[0031] It should be noted that if the coating sample used in the present invention is a liquid sample, the sample needs to be shaken before sampling; if the coating sample is a solid sample, the sample needs to be crushed to a diameter of less than 5 mm using a crushing device before sampling; if the coating sample is a solid-liquid mixed sample, the sample needs to be mixed before sampling.

[0032] As a more preferred embodiment of the method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry of the present invention, in step S1, the organic solvent A comprises at least one of methanol, toluene and acetone.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention establishes a method for detecting N-cyclohexyl toluenesulfonamide in coatings by gas chromatography-mass spectrometry. By optimizing the instrument analysis parameters, N-cyclohexyl toluenesulfonamide can obtain symmetrical chromatographic separation peaks in a relatively short time. Compared with other extraction solvents, when methanol is used as the extraction solvent, the matrix interference is small and the separation effect is optimal. The analytical test method of the present invention has a low detection limit, good precision, and a high sample spike recovery rate, which meets the test requirements of N-cyclohexyl toluenesulfonamide in coating products; the correlation coefficient reaches 0.9996 within the concentration range of 0.1-10.0 mg / L; the detection limit and quantitative limit are both low, only 0.0144 mg / L and 0.4316 mg / L respectively, and RSD% <2.1%; the average sample spike recovery rate is 97.6%-104.2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A chromatogram of a standard solution of N-cyclohexyl-p-toluenesulfonamide described in one embodiment;

[0035] Figure 2 A mass spectrum of a standard solution of N-cyclohexyl-p-toluenesulfonamide described in one embodiment;

[0036] Figure 3 The chromatograms of the coating samples are compared when the gas chromatograph injection port temperature is different;

[0037] Figure 4Comparison of the response values ​​of N-cyclohexyl-p-toluenesulfonamide corresponding to different extraction solvents;

[0038] Figure 5 Comparison of the average recovery rates of N-cyclohexyl-p-toluenesulfonamide at different extraction temperatures;

[0039] Figure 6 Comparison of the average recovery rates of N-cyclohexyl-p-toluenesulfonamide at different extraction times;

[0040] Figure 7 This is the standard working curve of N-cyclohexyl p-toluenesulfonamide. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The reagents or instruments used in the present invention without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0043] The instruments and reagents used in the present invention are as follows:

[0044] Gas chromatograph: Agilent 7890B; chromatographic column: HP-5ms (length 30 m, film thickness 0.25 μm, inner diameter 0.25 mm); mass spectrometer: Agilent 5977B.

[0045] The standard solution was prepared as follows: 10 mg of N-cyclohexyl-p-toluenesulfonamide was accurately weighed using a 100,000 graded analytical balance, dissolved in methanol and made up to 10 mL to obtain a 1000 mg / L stock solution, which was stored in a refrigerator at 4°C away from light; the stock solution was diluted stepwise with methanol to obtain a series of mixed standard working solutions of 0.1 mg / L, 0.5 mg / L, 1.0 mg / L, 2.0 mg / L, 5.0 mg / L, and 10.0 mg / L.

[0046] Example 1

[0047] A method for detecting N-cyclohexyl-p-toluenesulfonamide in a coating by gas chromatography-mass spectrometry, the method comprising the following steps:

[0048] S1. Sample pretreatment

[0049] Weigh 1.0g±0.1g (accurate to 0.1mg) of a representative coating sample, place it in a 20mL sample bottle, add 10mL of methanol; tighten the bottle cap, perform ultrasonic extraction at 40°C, and extract for 10min; let it stand for 5min after extraction, take the extraction solution and filter the sample with a 0.45μm filter membrane, put it into a 2ml injection vial, and perform qualitative and quantitative tests with a gas chromatography-mass spectrometer;

[0050] S2. Gas Spectrometry and Mass Spectrometry

[0051] The sample solution is detected by gas chromatography-mass spectrometry;

[0052] The chromatographic conditions were as follows:

[0053] Chromatographic column: HP-5ms (length 30m, film thickness 0.25μm, inner diameter 0.25mm); injection port temperature: 290℃, injection mode: splitless, column flow rate: 1.2mL / min, heating program: initial temperature 120℃, hold for 0min, increase to 250℃ at 15℃ / min, hold for 1min;

[0054] The mass spectrometry conditions were as follows:

[0055] Electron bombardment ion source; ionization energy: 70ev, ion source temperature: 230℃, quadrupole temperature: 150℃, solvent delay: 3min, acquisition mode: SIM, quantitative ions: 210, qualitative ions: 155, 91.

[0056] Example 2

[0057] The difference between Example 2 and Example 1 is that in step S2, among the chromatographic conditions, the injection port temperature is 250° C.; the rest is consistent with Example 1.

[0058] Example 3

[0059] The difference between Example 3 and Example 1 is that in step S2, among the chromatographic conditions, the injection port temperature is 200° C.; the rest is consistent with Example 1.

[0060] Experimental Example 1

[0061] Optimization of the temperature of the chromatographic column injection port: The function of the injection port in the gas chromatograph is to vaporize the sample and introduce it into the gas phase system. Therefore, the temperature of the injection port must be based on the basic principle of ensuring effective vaporization of the liquid analyte. Too low a temperature will lead to incomplete sample vaporization and broaden the sample peak, but too high a temperature will easily lead to sample decomposition. Comparing the abundance of Examples 1-3 at different injection port temperatures, such as Figure 3 As shown, 290℃ is the optimal injection port temperature.

[0062] Example 4

[0063] The only difference between Example 4 and Example 1 is that in the preparation of the standard solution and in step S1, the extractant is toluene.

[0064] Example 5

[0065] The only difference between Example 5 and Example 1 is that in the preparation of the standard solution and in step S1, the extractant is acetone.

[0066] Experimental Example 2

[0067] Optimization of organic solvents: The solvents in Examples 1, 4, and 5 were prepared into standard solutions, and the response values ​​of N-cyclohexyl-p-toluenesulfonamide at the same concentration were tested. The results are as follows: Figure 4 As shown, the response value of N-cyclohexyl-p-toluenesulfonamide in methanol solvent is the highest. Therefore, methanol is the preferred organic solvent in the present invention.

[0068] Example 6

[0069] The only difference between Example 6 and Example 1 is that in step S1, the sample bottle is extracted at a temperature of 25° C. after the bottle cap is tightened.

[0070] Example 7

[0071] The only difference between Example 7 and Example 1 is that in step S1, the sample bottle is extracted at a temperature of 60° C. after the bottle cap is tightened.

[0072] Experimental Example 3

[0073] Optimization of extraction temperature: The average recovery rates of N-cyclohexyl-p-toluenesulfonamide at different extraction temperatures in Examples 1, 6, and 7 were compared. Figure 5 As shown, the results show that when the extraction temperature is 25°C, the average recovery rate of N-cyclohexyl toluenesulfonamide is the highest, higher than 95%. When the temperature is 45°C, the recovery rate decreases relative to that of 25°C, but is still higher than 90%. When the temperature is raised to 60°C, the recovery rate drops sharply and the average recovery rate decreases. Considering the comprehensive extraction factors and recovery rate results, the optimal extraction temperature is 45°C.

[0074] Example 8

[0075] The only difference between Example 8 and Example 1 is that in step S1, the extraction time is 30 minutes.

[0076] Example 9

[0077] The only difference between Example 9 and Example 1 is that in step S1, the extraction time is 90 minutes.

[0078] Example 10

[0079] The only difference between Example 10 and Example 1 is that in step S1, the extraction time is 120 minutes.

[0080] Experimental Example 4

[0081] Optimization of extraction time: The average recovery rates of N-cyclohexyl-p-toluenesulfonamide at different extraction times in Examples 1, 8-10 were compared. Figure 6 As shown, the results show that when the extraction time increases from 30min to 60min, the average recovery rate of the target substance decreases slightly, but is still higher than 95%. When the extraction time increases from 60min to 90min and 120min, the recovery rate of the target substance decreases significantly. Considering the extraction factors and recovery rate results, the optimal extraction time is 60min.

[0082] Experimental Example 5

[0083] Standard working curve equation and detection limit

[0084] The 1000 mg / L stock solution was diluted step by step with methanol to a series of working solutions of 0.1, 0.5, 1.0, 2.0, 5.0, and 10.0 mg / L. The standard working curve was drawn with mass concentration X (mg / L) as the abscissa and peak area Y as the ordinate. The results showed that N-cyclohexyl-p-toluenesulfonamide had a good linear relationship in the range of 0.1-10 mg / L, and the linear correlation coefficient was 0.9996. The standard working curve of N-cyclohexyl-p-toluenesulfonamide is shown in the figure below: Figure 7 The linear equation and correlation coefficient of N-cyclohexyl p-toluenesulfonamide are shown in Table 1.

[0085] Table 1

[0086] Serial number Target compound Linear equations <![CDATA[Coefficient of correlation R 2 > 1 N-Cyclohexyl-p-toluenesulfonamide <![CDATA[Y=3.866×10 5 X-9.198×10 3 ]]> 0.9996

[0087] Method detection limit

[0088] Under the optimized analytical test conditions, the standard substance with the lowest concentration of the curve was analyzed by instrument. The detection limit (LOD) and quantification limit (LOQ) of N-cyclohexyl-p-toluenesulfonamide were determined by 3 times and 10 times the signal-to-noise ratio (S / N). The detection limit (LOD) and quantification limit (LOQ) were 0.0144 mg / L and 0.4316 mg / L respectively. The blank test results were all less than the detection limit of the method, which fully met the test requirements for N-cyclohexyl-p-toluenesulfonamide in coating products.

[0089] Precision and Accuracy Experiments

[0090] A blank sample was taken and three levels of stock solutions with concentrations of 0.1, 2.0, and 10.0 mg / L were added to perform spike recovery determination. Each spike level was tested in parallel three times. The results are shown in Table 2. As can be seen from Table 2, at the three spike levels, the average spike recovery of N-cyclohexyl-p-toluenesulfonamide was 97.6%-104.2%, indicating that the test method has high accuracy; the relative standard deviation is <2.1%, indicating that the analytical method has high accuracy, so this method can meet the test requirements.

[0091] Table 2

[0092]

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for detecting N-cyclohexyl-p-toluenesulfonamide in coatings by gas chromatography-mass spectrometry, characterized in that: The method comprises the following steps: S1. Prepare a standard solution containing N-cyclohexyl-p-toluenesulfonamide using organic solvent A; S2, using gas chromatography-mass spectrometry to detect the standard solution in step S1 and draw a standard curve; S3, using organic solvent B to ultrasonically extract N-cyclohexyl-p-toluenesulfonamide in the coating sample, and preparing a sample solution to be tested; S4, using a gas chromatography-mass spectrometer to detect the sample solution to be tested in step S3, and calculating the content of N-cyclohexyl-p-toluenesulfonamide in the sample solution to be tested according to the test result and the standard curve drawn in step S2; In step S1, the concentration of N-cyclohexyl-p-toluenesulfonamide in the standard solution is 0.1-10 mg / L; In the steps S2 and S4, the detection conditions of the gas chromatography-mass spectrometry are: The chromatographic conditions were as follows: Chromatographic column: Agilent HP-5ms; injection port temperature: 250-300°C, injection mode: splitless, column flow rate: 0.8-1.6 mL / min, heating program: initial temperature 120°C, hold for 0 min, increase the temperature to 250°C at 15°C / min, hold for 1 min; The mass spectrometry conditions were as follows: Electron bombardment ion source; ionization energy: 70ev, ion source temperature: 220-250℃, quadrupole temperature: 140-160℃, solvent delay: 3-6min, acquisition mode: SIM; The step S3 includes at least one of the following conditions: (d) The conditions of ultrasonic extraction were as follows: temperature was 45 °C and time was 60 min; (e) The organic solvent B is methanol.

2. The method for detecting N-cyclohexyl-p-toluenesulfonamide in coating by gas chromatography-mass spectrometry as claimed in claim 1, characterized in that: In the steps S2 and S4, the detection conditions of the gas chromatography-mass spectrometry are: The chromatographic conditions were as follows: Chromatographic column: Agilent HP-5ms; injection port temperature: 290°C, injection mode: splitless, column flow rate: 1.2 mL / min, heating program: initial temperature 120°C, hold for 0 min, increase the temperature to 250°C at 15°C / min, hold for 1 min; The mass spectrometry conditions were as follows: Electron bombardment ion source; ionization energy: 70ev, ion source temperature: 230℃, quadrupole temperature: 150℃, solvent delay: 3min, acquisition mode: SIM.

3. The method for detecting N-cyclohexyl-p-toluenesulfonamide in coating by gas chromatography-mass spectrometry as claimed in claim 1, characterized in that: In the step S3, the mass volume ratio of the coating sample to the organic solvent B is 1 g:(5-20) mL.

4. The method for detecting N-cyclohexyl-p-toluenesulfonamide in coating by gas chromatography-mass spectrometry as claimed in claim 1, characterized in that: In the step S3, the mass volume ratio of the coating sample to the organic solvent B is 1 g:10 mL.

5. The method for detecting N-cyclohexyl-p-toluenesulfonamide in coating by gas chromatography-mass spectrometry as claimed in claim 1, characterized in that: In the step S1, the organic solvent A comprises at least one of methanol, toluene and acetone.

6. The method for detecting N-cyclohexyl-p-toluenesulfonamide in coating by gas chromatography-mass spectrometry as claimed in claim 1, characterized in that: The ratio of the regression sum of squares of the standard curve to the total error sum of squares R 2 ≥99.9%.

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