A method for detecting ethanolamine in workplace air

Abstract

The present application relates to a method for detecting ethanolamine in workplace air. The method comprises: using a solvent desorption type acidic silica gel tube to collect workplace air to obtain a gas to be tested, wherein the workplace air includes ethanolamine and interfering impurities; placing the solvent desorption type acidic silica gel tube in a solvent desorption bottle, adding acetonitrile to dissolve the components in the gas to be tested, and obtaining an organic solution; respectively preparing a standard application solution of ethanolamine, performing gas chromatography detection with the standard application solution of ethanolamine and a blank control solution, and drawing an ethanolamine standard curve; mixing the organic solution with cyclohexanone and water to obtain a derivatization solution; using gas chromatography to detect the derivatization solution to obtain the characteristic peak area of ​​the addition product; calculating the concentration of ethanolamine in the derivatization solution, the volume of the derivatization solution, the volume of the solvent desorption type acidic silica gel tube, and the characteristic peak area of ​​the addition product according to the ethanolamine standard curve, and obtaining the content of ethanolamine.

Description

Technical Field

[0001] The present application relates to the field of chromatography detection technology, and in particular to a method for detecting ethanolamine in workplace air. Background Art

[0002] Ethanolamine, also known as monoethanolamine and monoethanolamine, has a molecular formula of C2H7ON, a melting point of 10.3°C, a boiling point of 170.8°C, a slight ammonia odor, and is a medium-viscosity liquid.

[0003] In the metal processing industry, ethanolamine is widely used as an additive. On the one hand, it can quickly cool the surface temperature of cutting tools and workpieces, and on the other hand, it reduces the rate of metal corrosion. During the metal processing process, ethanolamine quickly evaporates into the air in the workplace, causing respiratory tract, skin and eye irritation, nausea, and vomiting symptoms to workers, affecting their health. Therefore, it is very important to accurately detect the ethanolamine content in the air in the workplace. Summary of the invention

[0004] The present application provides a method for detecting ethanolamine in workplace air, so as to solve the technical problem of low accuracy in the existing detection of ethanolamine content in air.

[0005] In a first aspect, the present application provides a method for detecting ethanolamine in workplace air, the method comprising:

[0006] Using a solvent desorption type acidic silica gel tube to collect workplace air to obtain a gas to be tested, wherein the workplace air includes ethanolamine and interfering impurities;

[0007] Place a solvent desorption type acidic silica gel tube in a solvent desorption bottle, add acetonitrile to dissolve the components in the gas to be tested, and obtain an organic solution;

[0008] Prepare standard application solutions of ethanolamine respectively, perform gas chromatography detection on the standard application solutions of ethanolamine and blank control solutions, and draw a standard curve of ethanolamine;

[0009] The organic solvent is mixed with cyclohexanone and water to react with ethanolamine and cyclohexanone to generate an addition product, thereby obtaining a derivatized solution;

[0010] The derivatization solution is detected by gas chromatography to obtain the characteristic peak area of ​​the addition product of the derivatization solution;

[0011] The content of ethanolamine in the workplace air was obtained based on the ethanolamine standard curve, the characteristic peak area of ​​the addition product, the volume of the derivatization solution and the volume of the solvent desorption type acidic silica gel tube.

[0012] Optionally, the volume of the solvent desorption type acidic silica gel tube is 5-20 ml.

[0013] Optionally, the volume of acetonitrile added is 1 / 3 to 100% of the volume of the solvent desorption type acidic silica gel tube, the time for adding acetonitrile and mixing is 10-30 minutes, and the shaking time is at least 30 seconds.

[0014] Optionally, the ethanolamine standard curve uses the theoretical concentration value of ethanolamine in the ethanolamine standard application solution as the abscissa and the peak area as the ordinate.

[0015] Optionally, the stationary phase for gas chromatography detection parameters is dimethylpolysiloxane.

[0016] Optionally, gas chromatography detection parameters are: carrier gas flow rate 1-2 mL / min, air flow rate 250-400 mL / min, hydrogen flow rate 25-45 mL / min; chromatographic column heating program: initial temperature 80°C maintained for 1-3 min, then heated to 180-200°C at a heating rate of 15-20°C / min and maintained for 1-5 min.

[0017] Optionally, the column length of the chromatographic column is 25 to 45 m, the inner diameter of the column is 0.2 to 0.3 mm, and the thickness of the stationary phase is 3.2 to 5 μm.

[0018] Optionally, the volume ratio of the organic solvent to cyclohexanone is (12-20):1.

[0019] Optionally, the volume ratio of cyclohexanone to water is 1:(1-3).

[0020] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0021] According to the method provided in the embodiment of the present application, when the workplace air contains ethanolamine and interfering impurities, since ethanolamine has a strong interaction with the interfering impurities and esters, the chromatographic peak will tail, thereby affecting the quantitative accuracy; in addition, this interaction also leads to the broadening of the peak, reducing the separation degree and the detection sensitivity; therefore, the method of the present application uses acetonitrile to fully absorb the ethanolamine in the air, thereby improving the detection sensitivity. The analysis reason may be that: the solubility of the interfering impurities is low, which can reduce the effect of some interfering impurities on ethanolamine; further, the organic solvent is mixed with cyclohexanone and water, so that ethanolamine reacts with cyclohexanone in the aqueous solution state, thereby improving the signal intensity of ethanolamine and other alcohols or alcoholamine compounds in gas chromatography, thereby comprehensively improving the detection accuracy of ethanolamine in the workplace air. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 A schematic flow chart of a method for detecting ethanolamine in workplace air provided in an embodiment of the present application.

[0025] Figure 2 A chromatogram of ethanolamine in workplace air provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] Ethanolamine will volatilize in high-temperature workplaces, such as metal processing. Ethanolamine volatilizes into the air and causes respiratory, skin and eye irritation, nausea, and vomiting symptoms to workers, affecting human health. The exposure limits of ethanolamine in the air may vary from country to country, usually between 2-15ppm. The permissible exposure limits of ethanolamine in the air of the workplace in my country are stipulated by GBZ 2.1-2019, and the classification is stipulated by the National Occupational Safety and Health Standard (GBZ / T229). According to the latest standards, these limits usually include time-weighted average concentration (TWA) and short-term exposure limit (STEL). The time-weighted average concentration (TWA) is generally 3ppm (partial million concentration) or about 7.5mg / m³. The short-term exposure limit (STEL) is generally 6ppm or about 15mg / m³. In the "Occupational Exposure Limits for Hazardous Factors in the Workplace Part I: Chemical Hazardous Factors", it is stipulated that the STEL of ethanolamine is 15mg / m³ and the TWA is 8mg / m³.

[0028] Generally speaking, the ethanolamine content in the air may be between 2-30ppm, that is, 4.994mg / m³ to 74.9mg / m³ in the air. For such a low dose of ethanolamine in the air, it is very important to reduce the influence of gas substances in the air on the characteristic peak area of ​​the components to be detected when the gas chromatograph is used for detection.

[0029] Figure 1It is shown that an embodiment of the present application provides a method for detecting ethanolamine in workplace air.

[0030] like Figure 1 As shown, the present application provides a method for detecting ethanolamine in workplace air, and the method includes: steps 100 to 600.

[0031] Step 100, using a solvent desorption type acidic silica gel tube to collect workplace air to obtain a gas to be tested, wherein the workplace air includes ethanolamine and interfering impurities.

[0032] Workplace air may also include esters and other alcohol or alcoholamine compounds.

[0033] The study found that when using activated carbon tubes, alkaline silicone tubes, acidic silicone tubes, and ethanol solutions to sample ethanolamine in the workplace, the experiment found that the acidic silicone tube could retain the maximum amount of ethanolamine, while other collection reagents affected the content of ethanolamine in a fixed volume of air.

[0034] Step 200, placing a solvent desorption type acidic silica gel tube in a solvent desorption bottle, adding acetonitrile to dissolve the components in the gas to be measured, and obtaining an organic solvent.

[0035] Acetonitrile is an organic solvent with good polarity, which can usually dissolve a variety of polar and medium polar compounds. Ethanolamine is a polar compound containing hydroxyl and amino groups, which can achieve good solubility with the polar solvent acetonitrile through hydrogen bonding and dipole-dipole interaction. Acetonitrile can dissolve ethanolamine. Acetonitrile can also partially dissolve interfering impurities, especially low molecular weight interfering impurities, such as molecular weights of 300 to 400. Acetonitrile has extremely low solubility for interfering impurities with large molecular weights, and has a partial dissolving effect on interfering impurities with smaller molecular weights. The interfering impurities may be the product of the reaction of polyethanolamine.

[0036] Step 300: prepare standard application solutions of ethanolamine respectively, perform gas chromatography detection on the standard application solutions of ethanolamine and blank control solutions, and draw a standard curve of ethanolamine.

[0037] In this step, a standard application solution of ethanolamine of different concentrations can be prepared to obtain an ethanolamine standard curve. In some embodiments, other alcohol or amine compounds include diethanolamine and triethanolamine; accordingly, standard application solutions of ethanolamine, diethanolamine and triethanolamine can be prepared respectively, and gas chromatography detection is performed on the ethanolamine standard application solution, diethanolamine standard application solution and triethanolamine standard application solution with a blank control solution to draw an ethanolamine standard curve, a diethanolamine standard curve and a triethanolamine standard curve. Furthermore, the contents of diethanolamine and triethanolamine can be detected in subsequent steps according to the diethanolamine standard curve and the triethanolamine standard curve.

[0038] Exemplarily, different concentrations of ethanolamine standard stock solutions are added to a derivatization reagent stock solution, such as a mixture of cyclohexanone and water, for pre-column derivatization. After derivatization, a series of addition product standard solutions with a concentration gradient, also known as ethanolamine standard application solutions, are obtained for sample injection analysis;

[0039] A linear regression fitting was performed with the injection concentration as the abscissa and the peak area of ​​the standard as the ordinate to obtain a working curve for the determination of ethanolamine content.

[0040] According to the above scheme, the concentration of the ethanolamine standard stock solution is between 5 and 100 mg / L.

[0041] Step 400, mixing the organic solvent with cyclohexanone and water to allow ethanolamine and cyclohexanone to react to generate an addition product, thereby obtaining a derivatization solution.

[0042] When ethanolamine in an organic solvent is directly detected by gas chromatography, the area calculation is not accurate due to the weak signal of ethanolamine. Therefore, the organic solvent is mixed with cyclohexanone to cause a nucleophilic addition reaction. The generated derivatization product has a strong GC signal. The reaction product has a good gas phase FID signal response and can be well separated by the chromatographic column. Then, gas chromatography is used for detection and analysis to improve the accuracy of subsequent detection of characteristic peak areas.

[0043] The analysis revealed that ethanolamine reacted with cyclohexanone to generate an addition product containing hydroxyl and amino groups:

[0044] Step 500, detecting the derivatized solution by gas chromatography to obtain a characteristic peak area of ​​an addition product of the derivatized solution;

[0045] Step 600, obtaining the content of ethanolamine in the workplace air according to the ethanolamine standard curve, the characteristic peak area of ​​the addition product, the volume of the derivatization solution and the volume of the solvent desorption type acidic silica gel tube.

[0046] In some embodiments, the characteristic peak area A of the addition product of the derivatization solution corresponds to the concentration n1 of ethanolamine in the derivatization solution, and the calculation formula of the concentration n2 of ethanolamine in the workplace air can be:

[0047] n2=n1×v1 / v2×100%,

[0048] Among them, the concentration of ethanolamine in the derivatization solution is n1, the volume of the derivatization solution is v1, the volume of the solvent desorption type acidic silicone tube is v2; and the concentration of ethanolamine in the workplace air is n2.

[0049] In the embodiments of the present application, the method of the present invention is simple and accurate, can reduce the influence of interfering impurities and esters in the air on the detection of ethanolamine in the air, can simultaneously detect the content of ethanolamine and other alcohols or amine compounds, and is of great significance for monitoring the content of ethanolamine in the workplace, and has a low detection limit of 0.05 mg / m 3 .

[0050] In some embodiments, in order to facilitate portability and increase the sampling of air, the volume of the solvent desorption type acidic silica gel tube is 5-20 ml.

[0051] In some embodiments, in order to reduce the preservation effect of the solvent desorption type acidic silicone tube containing the gas to be tested, reduce air leakage during the storage process, and affect the detection result of the ethanolamine content in the solvent desorption type acidic silicone tube, acetonitrile is coated on the end of the solvent desorption type acidic silicone tube.

[0052] In some embodiments, the volume of acetonitrile added is 1 / 3 to 100% of the volume of the solvent desorption type acidic silica gel tube, the time for adding acetonitrile and mixing is 10-30 minutes, and the shaking time is at least 30 seconds.

[0053] In some embodiments, the ethanolamine standard curve uses the theoretical concentration of ethanolamine in the ethanolamine standard application solution as the abscissa and the peak area as the ordinate. Figure 2 The chromatogram of the addition product after dissolving ethanolamine in the test gas is shown.

[0054] In some embodiments, the stationary phase of the gas chromatography detection parameter is dimethylpolysiloxane. In some embodiments, based on the total mass of dimethylpolysiloxane, the dimethylpolysiloxane includes phenyl groups of 1% to 3% by mass. In some embodiments, based on the weight of dimethylpolysiloxane, the dimethylpolysiloxane does not include phenyl groups.

[0055] Ethanolamine is a polar compound, and a strong polar or medium polar stationary phase is generally selected. In order to reduce the influence of interfering impurities and esters on the detection of ethanolamine content, the present application adopts a weak polar chromatographic column with phenyl-bonded dimethyl polysiloxane as the stationary phase, which can further improve the separation effect between the compounds, reduce the tailing of the chromatographic peak, and improve the accuracy of the detection.

[0056] In some embodiments, the gas chromatography detection parameters are: carrier gas flow rate 1-2 mL / min, air flow rate 250-400 mL / min, hydrogen flow rate 25-45 mL / min; chromatographic column heating program: initial temperature 80°C maintained for 1-3 min, then heated to 180-200°C at a heating rate of 15-20°C / min and maintained for 1-5 min.

[0057] In the embodiment of the present application, the gas chromatography conditions of the detection method are reasonably controlled to ensure good separation and peak shape between the chromatographic peaks of each substance to be tested and the internal standard, thereby improving the accuracy of the detection. And under the same detection conditions, the content of ethanolamine can be accurately detected. In addition, a single injection can simultaneously detect alcohols and amines such as triethanolamine, triisopropanolamine, glycerol, etc. that may be contained in the sample, shortening the chromatographic peak time required for detection.

[0058] In some embodiments, the column length of the chromatographic column is 25 to 45 m, the inner diameter of the column is 0.2 to 0.3 mm, and the thickness of the stationary phase is 3.2 to 5 μm.

[0059] In some embodiments, other alcohol or alcoholamine compounds include: one or more of diethanolamine, triethanolamine, triisopropanolamine, diethanol monoisopropanolamine, and glycerol.

[0060] In some embodiments, the volume ratio of the organic solvent to cyclohexanone is (12-20): 1. Optionally, the volume ratio of the organic solvent to cyclohexanone is 15:1.

[0061] In some embodiments, the volume ratio of cyclohexanone to water is 1:(1-3). Alternatively, the volume ratio of cyclohexanone to water is 1:2.5.

[0062] The method of the present invention will be described in detail below with reference to embodiments, comparative examples and experimental data.

[0063] Example 1

[0064] This embodiment provides a method for detecting ethanolamine in workplace air, the method comprising the following steps:

[0065] Step 100, using a solvent desorption type acidic silicone tube to collect workplace air to obtain a gas to be tested, wherein the workplace air includes ethanolamine, interfering impurities, esters, and other alcohol or amine compounds; specifically comprising: taking multiple acidic silicone tubes and using an air sampling instrument to collect air for 8 minutes at a flow rate of 2 ml / min in a mobile phone metal cutting processing workshop, to obtain multiple groups of air samples, coating the end of the acidic silicone tube with a trace amount of acetonitrile and sealing the opening of the acidic silicone tube. The acidic silicone tube is stored and tested on the third day. The sampled acidic silicone tube is sent to two third-party testing agencies, which detect ethanolamine through a mass spectrometer. Referring to the ASTM D7599-16 standard, the average value of the results of the two agencies' tests is 62.3 mg / m 3 .

[0066] Step 200, placing a solvent desorption type acidic silicone tube in a solvent desorption bottle, adding acetonitrile to dissolve the components in the gas to be measured, and obtaining an organic solvent; specifically comprising: adding acetonitrile in a volume of 90% of the volume of the solvent desorption type acidic silicone tube, adding acetonitrile and mixing for 25 minutes, and shaking for at least 1 minute.

[0067] Step 300, respectively prepare standard application solutions of ethanolamine, perform gas chromatography detection on the standard application solutions of ethanolamine and blank control solutions, and draw a standard curve of ethanolamine; specifically, it includes: (1) preparing a mixed standard mother solution and a mixed standard reserve solution:

[0068] Preparation of mixed standard stock solution: accurately weigh ethanolamine, add acetonitrile to make up to 100 ml, mix well to obtain mixed standard stock solution;

[0069] Mixed standard stock solution: Accurately weigh 5 g of mixed standard stock solution and dilute it with acetonitrile to obtain standard solutions of various concentrations;

[0070] The ethanolamine mixed standard stock solutions of different concentrations were mixed with the derivatization reagent stock solution (the volume ratio of cyclohexanone to water in the derivatization reagent stock solution was 1:2), and the volume ratio of cyclohexanone in the ethanolamine mixed standard stock solution and the derivatization reagent stock solution was 15:1.

[0071] Table 1 Preparation of mixed standard stock solution

[0072]

[0073] The peak area was measured under the working conditions selected by the instrument, and each sample was injected three times. The standard curve was drawn with the peak area as the Y axis and the addition product content as the X axis. When the chromatographic detection calculation was performed, when the ethanolamine content was at least 2.805µg / ml to 560.8µg / ml, the standard curve formula of ethanolamine was y=13.8376x+72.1040, R=0.99934.

[0074] Step 400, mixing the organic solvent with cyclohexanone and water to obtain a derivatization solution; the volume ratio of the organic solvent to the cyclohexanone is 15:1, and the volume ratio of the cyclohexanone to the water is 1:2.

[0075] Step 500, using gas chromatography to detect the derivatized solution, and obtaining the characteristic peak area of ​​the addition product of the derivatized solution; the gas chromatography detection parameters are: carrier gas flow rate 1.8mL / min, air flow rate 260mL / min, hydrogen flow rate 25mL / min; chromatographic column heating program: initial temperature 80°C for 2min, then heating to 180°C at a heating rate of 16°C / min for 2min. The gas chromatography method uses an SE-30 chromatographic column. The column length of the chromatographic column is 36m, the column inner diameter is 0.28mm, and the stationary phase thickness is 4.2μm.

[0076] Step 600, obtaining the content of ethanolamine in the workplace air according to the ethanolamine standard curve, the characteristic peak area of ​​the addition product, the volume of the derivatization solution and the volume of the solvent desorption type acidic silica gel tube.

[0077] Example 2

[0078] The contents of this embodiment are basically the same as those of embodiment 1, except that in step 100, the acidic silicone tube opening is not coated with a small amount of acetonitrile at the end of the acidic silicone tube to seal the acidic silicone tube, but the acidic silicone tube is directly sealed.

[0079] Example 3

[0080] The contents of this embodiment are basically the same as those of embodiment 1, except that: the carrier gas flow rate is 1.2 mL / min, the air flow rate is 320 mL / min, and the hydrogen flow rate is 30 mL / min; the chromatographic column heating program: the initial temperature is 100°C and maintained for 1.5 min, then the temperature is increased to 185°C at a heating rate of 18°C / min and maintained for 2 min.

[0081] Example 4

[0082] The contents recorded in this embodiment are basically the same as those in embodiment 1, except that: the difference between this embodiment and embodiment 1 is: the carrier gas flow rate is 1.6 mL / min, the air flow rate is 360 mL / min, and the hydrogen flow rate is 42 mL / min; the chromatographic column heating program: the initial temperature is 120°C and maintained for 2 min, then the temperature is increased to 190°C at a heating rate of 15°C / min and maintained for 2.5 min.

[0083] Example 5

[0084] The difference between this embodiment and embodiment 1 is that the volume ratio of the organic solvent to cyclohexanone is 100:1; and the volume ratio of cyclohexanone to water is 1:2.

[0085] Example 6

[0086] The difference between this embodiment and embodiment 1 is that a chromatographic column Stabilwax-DA is used and the stationary phase is polyethylene glycol.

[0087] Example 7

[0088] The difference between this embodiment and embodiment 1 is that: a SE-54 chromatographic column is used, and the stationary phase is a copolymer of polydimethylsiloxane and 5% phenylsiloxane.

[0089] Comparative Example 1

[0090] The air in the workplace was collected by using a solvent desorption type acidic silica gel tube, and the end of the acidic silica gel tube was not coated with a trace amount of acetonitrile and then the opening of the acidic silica gel tube was sealed. According to the provisions of GBZ / T160.70-2004, ethanolamine in the air of the workplace was absorbed by 0.01 mol / L sulfuric acid solution, directly sampled, and analyzed by gas chromatography.

[0091] Comparative Example 2

[0092] The difference between this comparative example and Example 1 is that: step 400 is not performed, the organic solution is mixed with cyclohexanone and water to obtain a derivatization solution; step 500 is directly performed, and the organic solution is detected by gas chromatography. The concentration is calculated using a standard curve prepared by using the ethanolamine mixed standard stock solution.

[0093] Comparative Example 3

[0094] The difference between this comparative example and Example 1 is that the acetonitrile in Example 1 is replaced by acetone.

[0095] Comparative Example 4

[0096] The difference between this comparative example and Example 1 is that the acetonitrile in Example 1 is replaced by water.

[0097] Comparison of results

[0098] The samples in the embodiments and comparative examples were subjected to gas chromatography detection, and the injection was repeated 5 times. The results were averaged and the detection results are shown in Table 2.

[0099] Table 2. Examples and Comparative Examples Detection of ethanolamine content in workplace air.

[0100]

[0101] As can be seen from Table 2, through the embodiments and comparative examples, it can be known that by adopting the method, after the end of the acidic silicone tube is not coated with a trace amount of acetonitrile, the opening of the acidic silicone tube is sealed, acetonitrile is used to dissolve polar organic matter in the air, and the organic solvent is mixed with cyclohexanone and water to obtain a derivatized solution, ethanolamine in the air can be detected, interfering impurities and ester interference in the air can be removed, the signal intensity of the addition product during gas chromatography detection can be improved, and other substances or addition product contents are less to affect the area of ​​the characteristic peak of the addition product in the chromatogram, thereby affecting the detection result.

[0102] It can be seen from Example 1 and Example 6 that, since ethanolamine molecules contain polar groups such as amino groups and hydroxyl groups, according to the principle of similarity of the stationary phase, SE-30 chromatographic column is generally preferred as the separation column, but it is found that the area of ​​the characteristic peak of the addition product on the spectrum is affected by the solid phase substances related to the interfering impurities, thereby affecting the content of the addition product. It is speculated that it may be due to the fact that the measured component ethanolamine is too firmly combined with the stationary phase, which indicates that a stationary phase with less polarity, such as dimethyl polysiloxane, needs to be selected. By comparing Example 7 with Example 1, it can be seen that the stationary phase is a copolymer of polydimethylsiloxane and 5% phenyl siloxane, which reduces the peak area of ​​the addition product in the gas chromatogram. The possible reason for the analysis is that the phenyl group in the phenyl siloxane with a mass fraction of 5% has a certain binding force to cyclohexanone or the reaction product of cyclohexanone and ethanolamine, thereby reducing the peak area of ​​the addition product in the chromatogram.

[0103] It should be noted that, in this article, relational terms such as "first" and "second" 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 are intended to cover non-exclusive inclusion, so that the process, method, article or equipment 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 equipment. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0104] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for detecting ethanolamine in workplace air, characterized in that: The method comprises: Using a solvent desorption type acidic silica gel tube to collect workplace air to obtain a gas to be tested, wherein the workplace air includes ethanolamine and interfering impurities; Place a solvent desorption type acidic silica gel tube in a solvent desorption bottle, add acetonitrile to dissolve the components in the gas to be tested, and obtain an organic solution; respectively preparing standard application solutions of ethanolamine, performing gas chromatography detection on the standard application solutions of ethanolamine and blank control solutions, and drawing a standard curve of ethanolamine; The organic solvent is mixed with cyclohexanone and water to react with ethanolamine and cyclohexanone to generate an addition product, thereby obtaining a derivatized solution; The derivatization solution was detected by gas chromatography to obtain the characteristic peak area of ​​the addition product of the derivatization solution. The carrier gas flow rate was 1.8 mL / min, the air flow rate was 260-320 mL / min, and the hydrogen flow rate was 25-30 mL / min. The chromatographic column heating program was as follows: the initial temperature was 80-100°C and maintained for 1.5-2 min, then the temperature was increased to 180-185°C at a heating rate of 16-18°C / min and maintained for 1-2 min. The gas chromatography method used an SE-30 chromatographic column. The content of ethanolamine in the workplace air was obtained based on the ethanolamine standard curve, the characteristic peak area of ​​the addition product, the volume of the derivatization solution and the volume of the solvent desorption type acidic silica gel tube.

2. The method according to claim 1, characterized in that: The holding volume of the solvent desorption type acidic silica gel tube is 5-20 ml.

3. The method according to claim 1, characterized in that The volume of acetonitrile added is 1 / 3 to 100% of the volume of the solvent desorption type acidic silica gel tube, the time for adding acetonitrile and mixing is 10-30 minutes, and the shaking time is at least 30 seconds.

4. The method according to claim 1, characterized in that The ethanolamine standard curve uses the theoretical concentration value of ethanolamine in the ethanolamine standard application solution as the abscissa and the peak area as the ordinate.

5. The method according to claim 1, characterized in that The column length of the chromatographic column is 25 to 45 m, the inner diameter of the column is 0.2 to 0.3 mm, and the thickness of the stationary phase is 3.2 to 5 μm.

6. The method according to claim 1, characterized in that The volume ratio of the organic solvent and cyclohexanone is (12-20):

1.

7. The method according to claim 1, characterized in that The volume ratio of cyclohexanone to water is 1:(1-3).

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