Determination method for simultaneously and quantitatively analyzing various micromolecular organic amine compounds by GC-FID (Gas Chromatography-Flame Ionization Detector)

Abstract

The invention relates to a determination method for simultaneously and quantitatively analyzing a small-molecule organic amine compound by adopting GC-FID (Gas Chromatography-Flame Ionization Detector), which comprises the following steps: selecting a proper solvent as a diluent of the small-molecule organic amine compound, then adjusting program parameters to obtain a completely separated GC map, and calculating the concentration of a target object according to a peak area and a mixed standard curve established in advance. Various micromolecular organic amine compounds can be effectively and quantitatively detected at the same time. For micromolecular organic amine compounds of an acidic system and a neutral system, organic amine salt is converted into corresponding organic amine by adding strong base, and then quantitative analysis is carried out by the method, so that simultaneous quantitative analysis is realized.

Description

Technical Field

[0001] The invention relates to a quantitative analysis method for small molecule organic amine compounds, and in particular to a determination method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds in an acidic system and a neutral system by using GC-FID. Background Art

[0002] Alcoholamine compounds are organic compounds that contain both amino (-NH2) and hydroxyl (-OH) functional groups in their molecules. This type of compound is an important chemical product. Among them, ethanolamine, diethanolamine and triethanolamine are collectively referred to as ethanolamines, which are the most practical products among amino alcohols, accounting for 90% to 95% of the total amount of amino alcohols. They are widely used as dispersants, modifiers, cement enhancers, hydrogen sulfide absorbers, cosmetic humidifiers and emulsifiers, coating stabilizers, fuel additives and pharmaceutical intermediates for resins and rubbers, and play an important role in modern chemical production. N, N-dimethylethanolamine and N, N-diethylethanolamine are colorless organic bases with ammonia odor, and are widely used in the fields of chemical industry, medicine, etc. In addition, common alcoholamine compounds also include isopropanolamine, diisopropanolamine and triisopropanolamine, which are commonly used additives in fiber industry refining agents, antistatic agents, dyeing auxiliaries and fiber lubricants. They can also be used in the synthesis of synthetic detergents, cosmetics, lubricating oils, cutting oils, plasticizers and emulsifiers. As a derivative compound of triethanolamine, triethanolamine borate is also widely used in machinery, metallurgy, petrochemical and other industries, and has good anti-rust properties in cutting fluids, rolling oils, emulsified oils and rust inhibitors.

[0003] The above-mentioned alcoholamine compounds belong to a branch of organic amines, and organic amine compounds are a general term for organic compounds containing amino (-NH2, -NH-) functional groups. In life and industry, they are widely used in medicine, cosmetics, plastics, rubber, dyes, solvents and other fields. According to the size of the molecular weight, organic amine compounds with smaller molecular weight are collectively referred to as small molecule organic amines. Common small molecule organic amine compounds include cyclohexylamine, dicyclohexylamine, morpholine, diethylamine, diethylenetriamine, etc. Among them, alcoholamine compounds with smaller molecular weight also belong to small molecule organic amines.

[0004] The above-mentioned substances can be found everywhere in our daily life and production, and their determination and analysis has become an indispensable activity in the chemical industry. For the quantitative study of organic amine compounds, the currently known quantitative methods include gas chromatography external standard method, liquid chromatography external standard method and nuclear magnetic resonance hydrogen spectrum internal standard method, and these quantitative methods can usually only accurately quantify one or two or three organic compounds at the same time. However, some more complex sample systems usually have multiple organic amine compounds at the same time. These substances contain the same functional groups and similar molecular polarity, which makes them difficult to separate in gas chromatography and liquid chromatography, and the peak shifts on the nuclear magnetic resonance hydrogen spectrum are consistent or similar, which causes great interference to the quantitative analysis work. Summary of the invention

[0005] In order to solve the technical problems that small molecule organic amine compounds cannot be accurately quantified due to the similar structures between them, and that mixed amines easily react with acidic substances to form organic amine salts, which affects quantification, the present invention provides a method for simultaneously quantitatively analyzing multiple small molecule organic amine compounds using GC-FID.

[0006] A method for simultaneously and quantitatively analyzing a plurality of small molecule organic amine compounds by GC-FID comprises the following steps: Step 1: Select a diluent and prepare a mixed standard stock solution of a small molecule organic amine compound as a standard working solution; Step 2: Adjust the working parameters and temperature program of GC-FID to obtain a GC chart showing complete separation of each small molecule organic amine compound component; the temperature program requirements are: the lowest temperature range is 50°C above and below room temperature, and the highest temperature range is 300°C; the stage heating rate is 5°C-30°C / min; the stage constant temperature holding time is 0-10min; Step 3: Using the working parameters and temperature program set in step 2, add the standard working solution into the instrument for analysis and testing, and draw the standard concentration curve of each component through the computer; Step 4: Perform GC-FID detection on the sample to be tested according to the working parameters and heating program set in step 2, and calculate the concentration of each component based on the peak area of ​​each component and the corresponding standard concentration curve.

[0007] In some embodiments of the present invention, the small molecule organic amine compound in step one comprises ethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methyl-1-propanol, hydroxyethylethylenediamine, cyclohexylamine, dicyclohexylamine, diethylamine and diethylenetriamine.

[0008] In some embodiments of the present invention, in the standard working solution of the small molecule organic amine compound, the concentrations of diethylamine, N,N-dimethylethanolamine, 2-amino-2-methyl-1-propanol, cyclohexylamine, and dicyclohexylamine are not less than 50 mg / L; the concentrations of isopropanolamine and diisopropanolamine are not less than 100 mg / L.

[0009] In some embodiments of the present invention, in the standard working solution of the small molecule organic amine compound, the concentration of ethanolamine, diethanolamine, and triisopropanolamine is not less than 200 mg / L; the concentration of diethylenetriamine, hydroxyethylethylenediamine, and triethanolamine is not less than 500 mg / L Among the 13 small molecule organic amine compounds preferred in the present invention, the instrument detection limits are 50 mg / L, 100 mg / L, 200 mg / L, and 500 mg / L, respectively, by the determination method of the present invention. Therefore, when drawing the mixed standard working curve, the minimum concentration of different compounds shall not be lower than the instrument detection limit. Of course, when detecting other organic amine compounds, it is still necessary to determine the minimum concentration of each component in the prepared mixed standard working solution according to the instrument detection limit.

[0010] In some embodiments of the present invention, the diluent in step 1 is at least one of methanol, ethanol, acetone, and dimethyl sulfoxide.

[0011] Furthermore, the diluent in step one is at least one of methanol and ethanol.

[0012] When selecting a diluent, it is necessary to select one that is miscible with the target detection object. The organic solvents that are miscible with the above-mentioned small molecule organic amine compounds preferred in the present invention mainly include methanol, ethanol, acetone, N, N-dimethylformamide, and dimethyl sulfoxide; however, N, N-dimethylformamide and dimethyl sulfoxide have high boiling points, and the peaks on GC may overlap with some of the small molecule organic amine compounds; acetone is a controlled chemical that is easy to make drugs; on the whole, methanol and ethanol are preferred solvents.

[0013] In some embodiments of the present invention, the operating parameters of the GC-FID in step 2 are: 250-300° C. in the vaporization chamber. This is because the 13 small molecule organic amine compounds preferred in the present invention can all be vaporized within this temperature range. In other embodiments, the set temperature of the vaporization chamber needs to be determined according to the mixed vaporization temperature of the detection target.

[0014] In some embodiments of the present invention, in the working parameters of the GC-FID, the chromatographic column is a non-polar chromatographic column with a size of 50m*0.32mm*1μm; the carrier gas is nitrogen with a flow rate of 1-3ml / min.

[0015] In some embodiments of the present invention, the GC-FID operating parameters include an injection volume of 0.5-1.5 μL; a hydrogen flow rate of 30 ml / min; an air flow rate of 300 ml / min; a split ratio of one of 5:1, 10:1 and 20:1; and a FID detector temperature of 260-300°C.

[0016] In some embodiments of the present invention, the heating program in step 2 is: initial temperature 80°C, hold for 5 minutes, heat to 125°C at a rate of 15°C / min, heat to 185°C at a rate of 30°C / min, hold for 2 minutes, then heat to 200°C at a rate of 13°C / min, hold for 5 minutes, and finally heat to 250°C at a rate of 10°C / min, hold for 5 minutes.

[0017] In some embodiments of the present invention, if the system to be tested is an acidic system or a neutral system, a strong base can be first added to the system to be tested, and the amount of the strong base added can be adjusted according to the pH of the system. The organic amine salt in the system is converted into the corresponding organic amine, and then the organic amine is accurately measured by the quantitative method of GC-FID, and the concentration of the organic amine salt can be indirectly calculated.

[0018] Beneficial effects: Compared with the prior art, the present invention can effectively separate the components of a mixed system of various small-molecule organic amine compounds by adjusting the temperature rising program in GC-FID, thereby realizing accurate quantitative analysis of multiple components simultaneously and rapidly; the principle of strong base to weak base can also be used to convert organic amine salts in acidic and neutral systems into organic amines, and the derived organic amines can be further quantitatively detected, and the amount of organic amine salts can be determined according to the amount of organic amines, thereby solving the problem that small-molecule organic amine compounds in mixed systems (acidic, neutral) are difficult to quantify. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : The concentration calibration curve of diethylamine and ethanolamine in the embodiment; Figure 2 : The concentration calibration curve of isopropanolamine in the embodiment; Figure 3 : The concentration calibration curve of N,N-dimethylethanolamine and 2-amino-2-methyl-1-propanol in the embodiment; Figure 4 : The concentration calibration curve of cyclohexylamine in the embodiment; Figure 5 : The concentration calibration curve of diethylenetriamine and hydroxyethylethylenediamine in the embodiment; Figure 6 : The concentration calibration curve of diethanolamine in the embodiment; Figure 7 : The concentration calibration curve of diisopropanolamine and triethanolamine in the embodiment; Figure 8 : The concentration calibration curve of triisopropanolamine in the embodiment; Fig. 9 : The concentration calibration curve of dicyclohexylamine in the embodiment; Fig.10 : The GC spectrum of each component separation of the mixed standard working solution used in the embodiment, wherein: the peak at retention time 3.217min is diethylamine, 2.044min is ethanolamine, 4.697min is isopropanolamine, 5.013min is N, N-dimethylethanolamine, 5.430min is 2-amino-2-methyl-1-propanol, 7.849min is cyclohexylamine, 10.186min is diethylenetriamine, 10.353min is hydroxyethylethylenediamine, 10.701min is diethanolamine, 11.349min is diisopropanolamine, 14.906min is triethanolamine, 15.321min is triethanolamine, and 15.705min is dicyclohexylamine. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions 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 creative work are within the scope of protection of this application.

[0021] The present invention provides an analytical method for quantitatively determining small molecule organic amine compounds by GC-FID. The small molecule organic amine compounds include ethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methyl-1-propanol, hydroxyethylethylenediamine, cyclohexylamine, dicyclohexylamine, diethylamine and diethylenetriamine, a total of 13 components (the types and quantities of the compounds are only used as examples and are not limited here). The steps of the quantitative analysis method of the mixed system are as follows: Step 1: Select diluent methanol to prepare a mixed standard mother solution of small molecule organic amine compounds, where the concentration gradient of each component in the mixed mother solution is 500 mg / L, 800 mg / L, 1000 mg / L, 2000 mg / L, and 5000 mg / L as the standard working solution; Step 2: Adjust the operating parameters and temperature program of GC-FID (the operating parameters and temperature program described below are only used as examples. In actual application, they need to be adjusted accordingly according to the composition of the target object). The operating parameters are shown in Table 1-1: Table 1-1 GC-FID operating parameters The heating program is shown in Table 1-2: Table 1-2 GC-FID heating program According to the working parameters and temperature program set above, a GC chart showing complete separation of the components of each small molecule organic amine compound is obtained, as shown in FIG. Fig.10 As shown; Step 3: Add the standard working solution prepared in step 1 into the instrument, and draw the standard concentration curve of each component under the working parameters and temperature program set in step 2, such as Figure 1 , 2 , 3, 4, 5, 6, 7, 8, 9; Step 4: Perform GC-FID detection on the sample containing the above-mentioned small molecule organic amine compound according to the working parameters and heating program set in step 2, and calculate the concentration of each component based on the peak area of ​​each component and the corresponding standard concentration curve.

[0022] In order to investigate the precision and accuracy of the method, the present invention conducted six parallel determinations on 0.1 ml of mixed samples after spiked with three concentrations of low (500 mg / L), medium (1000 mg / L) and high (5000 mg / L). The spiked concentrations of the samples during the six parallel determinations of the three concentrations can be seen in Tables 1-3, 1-4 and 1-5: Table 1-3 Actual test concentrations of low concentration spikes Table 1-4 Actual test concentrations of medium concentration spikes Table 1-5 Actual test concentrations of high concentration spikes The precision is evaluated by calculating the standard deviation SD and relative standard deviation RSD of the parallel test results. The results are shown in Table 1-6: Table 1-6 Test precision of three spike concentrations The accuracy was evaluated by calculating the spiked concentration and average recovery of the parallel test results. The results are shown in Table 1-7: Table 1-7 Test accuracy of three spike concentrations It can be seen from the above results that the GC-FID test method provided by the present invention can quickly and accurately quantitatively analyze 13 small molecule organic amines simultaneously, and the method recovery rate is in the range of 90-110%, with excellent accuracy and precision, and has a certain reference value in the field of detection and analysis.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for simultaneously and quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID, characterized in that: The following steps are involved: Step 1: Select a diluent and prepare a mixed standard stock solution of a small molecule organic amine compound as a standard working solution; Step 2: Adjust the working parameters and temperature program of GC-FID to obtain a GC chart showing complete separation of each small molecule organic amine compound component; the temperature program requirements are: the lowest temperature range is 50°C above and below room temperature, and the highest temperature range is 300°C; the stage heating rate is 5°C-30°C / min; the stage constant temperature holding time is 0-10min; Step 3: Using the working parameters and temperature rise program set in step 2, draw the standard concentration curve of each component using the standard working solution; Step 4: Perform GC-FID detection on the sample to be tested according to the working parameters and heating program set in step 2, and calculate the concentration of each component based on the peak area of ​​each component and the corresponding standard concentration curve.

2. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID according to claim 1, characterized in that: The small molecule organic amine compound in step 1 includes ethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, 2-amino-2-methyl-1-propanol, hydroxyethylethylenediamine, cyclohexylamine, dicyclohexylamine, diethylamine and diethylenetriamine.

3. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID according to claim 2, characterized in that: In the standard working solution of the small molecule organic amine compound, the concentrations of diethylamine, N,N-dimethylethanolamine, 2-amino-2-methyl-1-propanol, cyclohexylamine and dicyclohexylamine are not less than 50 mg / L; the concentrations of isopropanolamine and diisopropanolamine are not less than 100 mg / L.

4. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID according to claim 2, characterized in that: In the standard working solution of the small molecule organic amine compound, the concentrations of ethanolamine, diethanolamine and triisopropanolamine are not less than 200 mg / L; the concentrations of diethylenetriamine, hydroxyethylethylenediamine and triethanolamine are not less than 500 mg / L.

5. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID according to claim 2, characterized in that: The diluent in step 1 is at least one of methanol, ethanol, acetone and dimethyl sulfoxide.

6. The method for simultaneously and quantitatively analyzing a plurality of small molecule organic amine compounds by GC-FID according to claim 5, characterized in that: The diluent in step 1 is at least one of methanol and ethanol.

7. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID according to claim 1, characterized in that: The operating parameters of the GC-FID in step 2 are: 250-300° C. in the vaporization chamber.

8. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID according to claim 7, characterized in that: In the working parameters of the GC-FID, the chromatographic column is a non-polar chromatographic column with a size of 50m*0.32mm*1μm; the carrier gas is nitrogen with a flow rate of 1-3ml / min.

9. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds by GC-FID according to claim 7, characterized in that: The GC-FID working parameters include an injection volume of 0.5-1.5 μL, a hydrogen flow rate of 30 ml / min, an air flow rate of 300 ml / min, a split ratio of 5:1, 10:1 and 20:1, and a FID detector temperature of 260-300°C.

10. The method for simultaneously quantitatively analyzing a plurality of small molecule organic amine compounds using GC-FID according to claim 1, characterized in that: The heating program in step 2 is as follows: initial temperature 80°C, hold for 5 min, heat to 125°C at a rate of 15°C / min, heat to 185°C at a rate of 30°C / min, hold for 2 min, then heat to 200°C at a rate of 13°C / min, hold for 5 min, and finally heat to 250°C at a rate of 10°C / min, hold for 5 min.

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