A method for determining the content of components in a propylene oxide reactor sample by gas chromatography external standard method

Abstract

The present application relates to the technical field of detection analysis, and particularly relates to a method for determining the component content of a propylene oxide reactor sample by gas chromatography external standard method, comprising the following steps: after physical separation pretreatment of a gas-liquid two-phase sample in a propylene oxide reactor outlet sampling steel cylinder, a gas chromatograph equipped with a hydrogen flame ionization detector is used, under specified chromatographic conditions, to inject an appropriate amount of sample into the chromatographic system, a standard curve is established by external standard method, and the content of each component is calculated. The method can quickly and accurately determine the component content of the propylene oxide reactor sample, has high accuracy and high precision, and provides accurate data support for process parameter optimization. Through the synergistic matching of the optimization of the gas-liquid two-phase separation pretreatment process and the chromatographic analysis conditions, the problems of poor separation effect and poor repeatability in the analysis process of the propylene oxide reactor outlet sample are solved.

Description

Technical Field

[0001] This invention relates to the field of detection and analysis technology, and to a method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard. Background Technology

[0002] Propylene oxide (PO) is an important organic chemical raw material, and its derivatives are widely used in polyether polyols, propylene glycol, nonionic surfactants, oilfield demulsifiers, and other fields. In recent years, domestic demand for propylene oxide has continued to grow. In 2021, China's apparent consumption of propylene oxide reached 3.5 million tons, and in 2022 it exceeded 3.8 million tons, with an average annual growth rate of approximately 8%. Currently, the main domestic propylene oxide production processes include the chlorohydrin method, the co-oxidation method, and the direct oxidation method. As of 2024, the global HPPO method accounted for approximately 28%, and the domestic share was approximately 13%. However, with the advancement of environmental policies and technological breakthroughs, HPPO will become the mainstream process in the future, and both domestic and international shares are showing a rapid growth trend.

[0003] In downstream applications of propylene oxide, polyether polyols account for the largest share (approximately 75%), mainly used in the production of polyurethane foam; followed by propylene glycol (approximately 15%), used in unsaturated polyester resins, cosmetics, and pharmaceuticals. According to the "2024 Global Propylene Oxide Market Report," the global propylene oxide market is projected to grow at a CAGR of 5.2% from 2024 to 2029, primarily driven by end-user demand from building insulation materials, automotive seating, and medical devices.

[0004] With increasingly stringent environmental regulations and capacity expansion, developing efficient and low-energy-consumption propylene oxide (HPPO) production processes has become a key focus in the industry. It is necessary to develop a gas chromatography analysis method for propylene oxide samples to accurately determine the content of various components in the propylene oxide reactor outlet samples. This would provide a rapid and accurate detection method for HPPO production, which is crucial for controlling product quality and optimizing production processes. Summary of the Invention

[0005] The purpose of this invention is to provide a method for determining the component content of propylene oxide reactor samples using gas chromatography with external standard method. This method features short analysis time, high accuracy, and high repeatability. The technical solution adopted is as follows:

[0006] A method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard method, characterized by comprising the following steps:

[0007] Step 1: Setting Gas Chromatography Conditions

[0008] The chromatographic column is a highly polar polyethylene glycol quartz capillary column with dimensions of 60m × 0.32mm × 1μm.

[0009] The column oven uses a gradient heating mode, with temperatures ranging from 50℃ to 250℃.

[0010] Split injection was used with a split ratio of 50:1.

[0011] The injection port temperature is 250℃;

[0012] The flow rate of the carrier gas nitrogen was 2.0 mL / min;

[0013] The detector has an air flow rate of 400 mL / min and a hydrogen flow rate of 30 mL / min.

[0014] A hydrogen flame ionization detector was used at a temperature of 250℃. Samples were injected for analysis after the baseline stabilized for 0.5 hours.

[0015] Step 2: Preparation of standard solutions: Dissolve the reagents of each impurity component in methanol to prepare standard solutions with a mass concentration of 0.01%-5% for each impurity component;

[0016] Step 3: Take the standard solution from Step 2, inject it into the gas chromatograph, analyze it under the recommended chromatographic conditions, measure the peak area of ​​each component, and calculate the correction factor for each component.

[0017] Step 4: After separating the liquid and gas phases of the propylene oxide reactor sample cylinder, accurately weigh and record the mass of each phase.

[0018] Step 5: Based on the mass of the liquid and gas phases of the propylene oxide reactor sample cylinder in Step 4, calculate the total content of the gas phase in the sample. The total content of the gas phase is the total content of propylene and propane.

[0019] Step 6: Take the liquid solution from Step 4 and inject it into the gas chromatograph. Separate the components of the sample solution through the chromatographic column and calculate the content of each component in the liquid sample using the external standard method.

[0020] Preferably, the column temperature in step one starts at 50°C and is increased in two stages, as follows: the initial temperature of 50°C is maintained for 17 minutes, then increased to 100°C at 10°C / min and maintained for 0 minutes, and then increased to 250°C at 20°C / min and maintained for 5 minutes.

[0021] Preferably, the volume of the standard solution in step two is 1L, and its concentration by mass fraction is: 1-methoxy-2-propanol: 0.1%, 2-methoxy-1-propanol: 0.1%, 1,2-propanediol: 0.1%, 2-propanol: 5%, acetone: 0.1%, ethanol: 0.15%, dimethoxymethane: 0.01%, propylene oxide: 12%, methanol: equilibrium.

[0022] As a preferred embodiment, step three is as follows: take the standard solution from step two and put it into a 2 mL chromatographic vial, place it in the chromatograph's injection tray, use an autosampler to draw 1.0 μL of the sample solution, analyze it under the recommended chromatographic conditions, repeat the above standard solution measurement three times, measure the peak area of ​​each component, and calculate the correction factor for each component.

[0023] As a preferred option, step four is as follows: use a fully purged sampling cylinder to ensure that it is full of the sample to be tested; install a vent connector at the cylinder outlet, weigh the total mass of "cylinder + vent connector" with a balance with an accuracy of 0.01g, and record it as m1;

[0024] Next, fix the gas cylinder vertically to the fume hood bracket, and slowly open the upper shut-off valve to release the gas phase sample; after standing for 20 minutes, close the valve, re-weigh the total mass of "gas cylinder + vent connector", and record it as m2;

[0025] Then, transfer all the remaining liquid sample in the cylinder to a 1000mL beaker; weigh the liquid sample in the beaker and record it as m3.

[0026] Because the propane and propylene in the gas phase are not mixed evenly with the liquid phase during the injection, the repeatability of the injection is particularly poor. Therefore, the above method can be used to measure the mass of the gas phase and the liquid phase separately.

[0027] Preferably, the calculation of the total content of propylene and propane in step five is as shown in the following formula:

[0028] The total content W1 of propylene and propane is calculated, and its mass fraction is expressed as %:

[0029] ;

[0030] Where m1 represents the mass of the cylinder and the sample, in g; m2 represents the mass of the cylinder and the sample after the gas phase is released, in g; and m3 represents the mass of the liquid sample in the cylinder, in g.

[0031] As a preferred embodiment, step six specifically involves: taking the liquid solution from step four, filling a 2mL chromatographic vial, placing it in the chromatograph's injection tray, using an autosampler to draw 1.0μL of the sample solution, analyzing it under recommended chromatographic conditions, and calculating the content of each component in the sample using the external standard method.

[0032] Preferably, the content of the analyte i in the sample is calculated according to the following formula, expressed as a % mass fraction:

[0033] ;

[0034] Where fi represents the correction factor for component i in the sample; A 试样i This represents the peak area of ​​component i in the sample.

[0035] Preferably, the nitrogen gas has a purity greater than 99.999%; the hydrogen gas has a purity greater than 99.999%; and the air is purified air.

[0036] Preferably, the standard liquid used to test the reproducibility, precision and accuracy of the method has a volume of 1L, and the mass fraction of each component is as follows: 1-methoxy-2-propanol: 0.1%, 2-methoxy-1-propanol: 0.1%, 1,2-propanediol: 0.1%, 2-propanol: 5%, acetone: 0.1%, ethanol: 0.15%, dimethoxymethane: 0.01%, propylene oxide: 12%, methanol: equilibrium.

[0037] Because propylene oxide reacts directly with water to produce 1,2-propanediol in the absence of a catalyst or under mild conditions. The main reaction is: CH3-CH-CH2O + H2O → CH3-CH(OH)-CH2OH, i.e., (propylene oxide) + (water) → (1,2-propanediol). The reaction mechanism is as follows: propylene oxide is a three-membered cyclic ether with high ring strain and is very unstable, easily subjected to nucleophilic attack and ring-opening. The oxygen atom in the water molecule (H2O) acts as a nucleophile, attacking the sterically less hindered carbon atom on the epoxy ring (usually the carbon atom bonded to a hydrogen atom, i.e., the carbon on CH2-), causing the ring to open and producing propylene glycol. Therefore, methanol is used as the solvent in this invention.

[0038] The beneficial effects of this invention are:

[0039] This invention provides an efficient analytical method for separating and detecting the content of various components in the reactor outlet sample of a propylene oxide unit. Firstly, effective pre-separation of the gas and liquid phases in the sample ensures complete separation, avoiding the poor repeatability issues caused by uneven mixing of the gas and liquid phases during traditional high-pressure liquid injection valve sampling. The implementation of this invention can significantly improve product quality control and reduce production costs, demonstrating significant economic benefits and widespread application value. This method is particularly suitable for monitoring key nodes in the propylene oxide production process, providing reliable data support for process optimization and product quality improvement. Through innovative gas-liquid two-phase pre-separation technology and phase separation determination method, this invention solves the problems of poor repeatability and low analytical accuracy in traditional detection methods, providing an efficient, reliable, and practical solution for component analysis in the propylene oxide production process. Attached Figure Description

[0040] Figure 1 This is a chromatogram of a standard sample solution provided in an embodiment of the present invention;

[0041] Figure 2 This is a chromatogram of the sample solution provided in an embodiment of the present invention. Detailed Implementation

[0042] To deepen understanding and mastery of the present invention, the method of the present invention will be further described in detail below with reference to embodiments. It should be noted that the specific embodiments described herein are only for illustration and explanation of the present invention and do not constitute a limitation on the scope of protection of the present invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments used are not specified, they are all conventional products that can be purchased commercially.

[0043] A method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard method includes the following steps:

[0044] Step 1: Establishment of Gas Chromatography Conditions

[0045] Equipment selection: The gas chromatograph is equipped with an FID detector. The instrument parameters are shown in the table below:

[0046] Table 1 Recommended Chromatographic Parameters

[0047]

[0048] Step 2: Preparation of standard solutions

[0049] ①Prepare reagents: 1-methoxy-2-propanol, 2-methoxy-1-propanol, 1,2-propanediol, 2-propanol, acetone, ethanol, dimethoxymethane, propylene oxide, and methanol are all of chromatographic grade to ensure that the prepared standard solutions are accurate.

[0050] ②Tool preparation: A precise electronic balance (1 / 1000).

[0051] Appropriate containers (such as 100 ml or 200 ml beakers or Erlenmeyer flasks).

[0052] Glass rod, graduated cylinder or pipette (used for weighing liquid components).

[0053] Oscillator or ultrasonic mixing device (for thorough mixing);

[0054] ③ Standard solution concentration (mass fraction): 1-methoxy-2-propanol: 0.1%, 2-methoxy-1-propanol: 0.1%, 1,2-propanediol: 0.1%, 2-propanol: 5%, acetone: 0.1%, ethanol: 0.15%, dimethoxymethane: 0.01%, propylene oxide: 12%, methanol: equilibrium;

[0055] Based on the mass fraction of each component in the standard solution, calculate the approximate volume of each component in the standard solution. For example, to prepare 1 L of standard solution, then:

[0056] Table 2. Standard Solution Mass Fraction Volume Comparison Table

[0057]

[0058] ④Preparation of solution:

[0059] First, measure an appropriate amount of methanol as the main solvent in a 1000ml volumetric flask, accurately weigh it, and record the mass.

[0060] As shown in Table 2, other components were transferred and added in sequence: 1-methoxy-2-propanol, 2-methoxy-1-propanol, 1,2-propanediol, 2-propanol, acetone, ethanol, dimethoxymethane, and propylene oxide. The mass of each component was accurately weighed and recorded after each addition.

[0061] After each addition, gently stir or shake with a glass rod to ensure thorough mixing;

[0062] Finally, add methanol and bring the volume to 1000ml. Accurately weigh the contents and record the total mass.

[0063] Calculate the mass fraction of each component based on its mass in the standard solution;

[0064] ⑤ Mixing and Calibration: After mixing all ingredients, shake thoroughly to ensure even distribution of each component. A vibrator or ultrasonic cleaner can be used to assist in mixing.

[0065] = 6 * GB3 * MERGEFORMAT ⑥ Quality Control: After preparation, the solution should be subjected to quality control testing to ensure that the concentration of each component meets the preset standard;

[0066] = 7 * GB3 * MERGEFORMAT ⑦ Storage and Labeling: Transfer the prepared standard solution to brown ampoules or suitable containers, and label the solution with its composition, preparation date, and expiration date. Store in a cool, dark place to prevent evaporation and contamination.

[0067] Step 3: Establish the standard curve

[0068] Take the standard solution sample from step two and put it into a 2mL chromatographic vial. Place the vial into the chromatograph's injection tray and analyze it under the recommended chromatographic conditions. Record the chromatogram and perform regression analysis on the obtained peak area and the corresponding solubility of the standard working solution. Analyze the above standard solution three times under the recommended chromatographic conditions and measure the peak area of ​​each component. Calculate the correction factor for each component.

[0069] Step 4: After separating the liquid and gas phases of the sample from the propylene oxide reactor outlet cylinder, accurately weigh and record the mass of each phase, and calculate the propylene + propane content in the sample.

[0070] Step 5: Take the liquid solution from Step 4 and inject it into the gas chromatograph. Separate the components of the sample solution through the chromatographic column and calculate the content of each component in the liquid sample using the external standard method.

[0071] The reproducibility of the method of the present invention was examined.

[0072] The same sample was selected and, under normal and correct operating conditions, by the same operator in the same laboratory, using the same instrument, and within a short period of time, seven single tests were performed on the sample. Details are as follows:

[0073] 1. Sample preparation

[0074] Standard solutions (mass fraction): 1-Methoxy-2-propanol: 0.1%, 2-Methoxy-1-propanol: 0.1%, 1,2-Propanediol: 0.1%, 2-Propanol: 5%, Acetone: 0.1%, Ethanol: 0.15%, Dimethoxymethane: 0.01%, Propylene oxide: 12%, Methanol: Equilibrium.

[0075] Note: The standard solutions used in this determination must be prepared by a qualified institution.

[0076] 2. Chromatographic conditions

[0077]

[0078] 3. Testing Operation Connect all parts of the instrument to the power supply. After the detector temperature reaches the set temperature, ignite it and allow it to stabilize for 0.5 hours. Once the baseline is stable, inject the sample for analysis. Use a pipette to draw the solution from step 1 into the sample vial, place it in the chromatograph's injection tray, and use the autosampler to draw 1.0 μL of the sample solution and inject it into the gas chromatograph.

[0079] The test results are shown in the table below.

[0080] Table 1 Reproducibility Test Results

[0081]

[0082] According to the data in Table 1, the analytical results of each component of the sample showed good reproducibility and reliability. The standard deviation (SD) of each component ranged from 0.01% to 0.2%, and the relative standard deviation (RSD) ranged from 0.1% to 2.5%, both significantly lower than the 5% threshold required for conventional analysis. Meanwhile, the relative standard deviation (RSD) of the peak times of each component in the chromatographic analysis was less than 1%, indicating good stability of the chromatographic system. Considering both SD and RSD indicators, this analytical method has excellent precision and repeatability, and can meet the requirements of quantitative analysis.

[0083] Analyzing the precision and accuracy of the external standard method.

[0084] The same sample was selected and, under normal and correct operating conditions, by the same operator in the same laboratory, using the same instrument, and within a short period of time, seven single tests were performed on the sample. Details are as follows:

[0085] 1. Sample preparation

[0086] Standard solutions (mass fraction): 1-Methoxy-2-propanol: 0.1%, 2-Methoxy-1-propanol: 0.1%, 1,2-Propanediol: 0.1%, 2-Propanol: 5%, Acetone: 0.1%, Ethanol: 0.15%, Dimethoxymethane: 0.01%, Propylene oxide: 12%, Methanol: Equilibrium.

[0087] Note: The specific standard values ​​and relative expanded uncertainties of the standard solutions used in this determination are shown in the table below:

[0088]

[0089] 2. Chromatographic conditions

[0090]

[0091] 3. Testing Operation Connect all parts of the instrument to the power supply. After the detector temperature reaches the set temperature, ignite it and allow it to stabilize for 0.5 hours. Once the baseline is stable, inject the sample for analysis. Use a pipette to draw the solution from step 1 into the sample vial, place it in the chromatograph's injection tray, and use the autosampler to draw 1.0 μL of the sample solution and inject it into the gas chromatograph.

[0092] The test results are shown in the table below.

[0093] Table 2. Test Results of Standard Solution

[0094]

[0095] Table 3. Precision Results of Standard Solution

[0096]

[0097] As shown in Table 3, the standard deviation (SD) of the measured results for each component in the sample ranged from 0.00009% to 0.02404%, and the relative standard deviation (RSD) ranged from 0.06495% to 4.75978%. The RSDs were generally below the conventional threshold of 5%, indicating good repeatability and high precision of the method. Furthermore, the normalized deviation (En value) of all components was less than 1 (|En|<1), further verifying the consistency between the measured results and the reference values, demonstrating high accuracy and controllable systematic error.

[0098] Example

[0099] This embodiment describes the measured content of each component in the reactor outlet sample of a propylene oxide unit.

[0100] 1. Sample preparation

[0101] The sampling cylinder is fully replaced and filled with sample. The outlet of the sampling cylinder is connected to the vent connector. The mass of the sampling cylinder and the vent connector is accurately weighed and recorded as m1, accurate to 0.01g.

[0102] Place the gas cylinder vertically on the cylinder support in the fume hood, slowly open the valve at the top of the cylinder to release the gas phase sample from the cylinder, let it stand for 20 minutes, then close the valve at the top and weigh the cylinder and vent connector again, and record the mass as m2, accurate to 0.01g.

[0103] Next, place the liquid sample from the cylinder into a 1000mL beaker, weigh the liquid sample, and record the mass as m3, accurate to 0.01g.

[0104] 2. Chromatographic conditions

[0105] Gas chromatograph: Agilent 8890. Injector temperature: 250℃; Agilent DB-WAXetr gas chromatograph column, 60m × 0.32mm × 1μm, column temperature: initial temperature 50℃, hold for 17min, increase to 100℃ at 10℃ / min, hold for 0min, then increase to 250℃ at 20℃ / min, hold for 5min; FID detector, detector temperature 300℃; air: 400mL / min, carrier gas flow rate: 1.5mL / min, hydrogen: 30mL / min, split ratio: 50:1. 3. Testing Operation Connect all parts of the instrument to the power supply. After the detector temperature reaches the set temperature, ignite it and allow it to stabilize for 0.5 hours. Once the baseline is stable, inject the sample for analysis. Use a pipette to aspirate the liquid sample from step 1 into the injection vial, place it in the chromatograph's injection tray, and use the autosampler to aspirate 1.0 μL of the sample solution and inject it into the gas chromatograph.

[0106] 4. Calculation

[0107] 4.1 The light phase in the heavy phase sample is propylene + propane. The content of the light phase, W1, is calculated as % (mass fraction):

[0108]

[0109] Where: m1—mass of the cylinder and the sample, in grams;

[0110] m2 — Mass of the cylinder and sample after the gas phase is released, in grams;

[0111] m3 — Mass of the liquid phase sample in the cylinder, in grams.

[0112] 4.2 Calculate the content of the analyte i in the sample according to the following formula, expressed as a % mass fraction:

[0113]

[0114] Where: fi — correction factor for component i in the sample;

[0115] A 试样i —The peak area of ​​component i in the sample.

[0116] The correction factor and peak area are automatically calculated and measured by the chromatography workstation. This is a built-in function of the chromatography workstation and is existing technology, so it will not be described in detail here.

[0117] The calculation results are rounded to two decimal places, and then the content of each component in the sample is calculated.

[0118] Finally, it should be noted that the embodiments of the present invention are merely illustrative examples for explaining the invention and are not intended to limit the implementation of the invention. Unless specifically limited, the terminology used in this invention has the meaning commonly understood by those skilled in the art. The embodiments described in this invention are for exemplary purposes only and are not intended to limit the scope of protection of the invention. Those skilled in the art can make various other substitutions, changes, and improvements within the scope of this invention; therefore, the invention is not limited to the above embodiments but is defined only by the claims.

Claims

1. A method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard, characterized in that, Includes the following steps: Step 1: Setting Gas Chromatography Conditions The chromatographic column is a highly polar polyethylene glycol quartz capillary column with dimensions of 60m × 0.32mm × 1μm. The column oven uses a gradient heating mode, with the temperature increasing from 50℃ to 250℃. The column temperature starts at 50℃ and is increased in two stages, as follows: the initial temperature is 50℃ and held for 17 minutes, then increased to 100℃ at 10℃ / min and held for 0 minutes, and then increased to 250℃ at 20℃ / min and held for 5 minutes. Split injection was used with a split ratio of 50:

1. The injection port temperature is 250℃; The flow rate of the carrier gas nitrogen was 2.0 mL / min; The detector has an air flow rate of 400 mL / min and a hydrogen flow rate of 30 mL / min. A hydrogen flame ionization detector was used at a temperature of 250℃. Samples were injected for analysis after the baseline stabilized for 0.5 hours. Step 2: Preparation of standard solutions: Dissolve the reagents of each impurity component in methanol to prepare standard solutions with a mass concentration of 0.01%-5% for each impurity component; the volume of the standard solution is 1L, and its concentration by mass fraction is as follows: 1-methoxy-2-propanol: 0.1%, 2-methoxy-1-propanol: 0.1%, 1,2-propanediol: 0.1%, 2-propanol: 5%, acetone: 0.1%, ethanol: 0.15%, dimethoxymethane: 0.01%, propylene oxide: 12%, methanol: equilibrium; Step 3: Take the standard solution from Step 2, inject it into the gas chromatograph, analyze it under the recommended chromatographic conditions, measure the peak area of ​​each component, and calculate the correction factor for each component. Step 4: After separating the liquid and gas phases of the propylene oxide reactor sample sampling cylinder, accurately weigh and record the mass of each phase. Specifically, Step 4 involves using a fully purged sampling cylinder to ensure it is full of the sample to be tested; installing a vent connector at the cylinder outlet; weighing the total mass of the cylinder and vent connector using a balance with an accuracy of 0.01g and recording it as m1. Next, fix the gas cylinder vertically to the fume hood bracket, and slowly open the upper shut-off valve to release the gas phase sample; after standing for 20 minutes, close the valve, re-weigh the total mass of "gas cylinder + vent connector", and record it as m2; Then, transfer all the remaining liquid phase sample in the cylinder to a 1000mL beaker; weigh the liquid phase sample in the beaker and record it as m3; Step 5: Based on the mass of the liquid and gas phases of the propylene oxide reactor sample taken from the cylinder in Step 4, calculate the total gas phase content in the sample; the calculation of the total propylene and propane content in Step 5 is shown in the following formula: The total content W1 of propylene and propane is calculated, and its mass fraction is expressed as %: ； Where m1 represents the mass of the cylinder and the sample, in g; m2 represents the mass of the cylinder and the sample after the gas phase is released, in g. m3 represents the mass of the liquid sample in the cylinder, in grams. Step 6: Take the liquid solution from Step 4 and inject it into the gas chromatograph. Separate the components of the sample solution through the chromatographic column and calculate the content of each component in the liquid sample using the external standard method.

2. The method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard as described in claim 1, characterized in that, Step 3 is as follows: Take the standard solution from step 2 and put it into a 2mL chromatographic vial. Place the vial into the chromatograph's injection tray, use an autosampler to draw 1.0μL of the sample solution, and analyze it under the recommended chromatographic conditions. Repeat the above standard solution measurement three times, measure the peak area of ​​each component, and calculate the correction factor for each component.

3. The method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard method as described in claim 1, characterized in that, Step six is ​​as follows: Take the liquid solution from step four, put it into a 2mL chromatographic vial, place it in the chromatograph's injection tray, use an autosampler to draw 1.0μL of the sample solution, analyze it under the recommended chromatographic conditions, and calculate the content of each component in the sample using the external standard method.

4. The method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard method as described in claim 3, characterized in that, Calculate the content of the analyte i in the sample using the following formula, expressed as a % mass fraction: ； Where fi represents the correction factor for component i in the sample; A 试样i This represents the peak area of ​​component i in the sample.

5. The method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard method as described in claim 1, characterized in that, The nitrogen gas has a purity greater than 99.999%; the hydrogen gas has a purity greater than 99.999%; and the air is purified air.

6. The method for determining the component content of a propylene oxide reactor sample using gas chromatography with external standard as described in claim 1, characterized in that, The reproducibility, precision, and accuracy of the method were tested using a standard solution with a volume of 1 L and the mass fractions of each component were as follows: 1-methoxy-2-propanol: 0.1%, 2-methoxy-1-propanol: 0.1%, 1,2-propanediol: 0.1%, 2-propanol: 5%, acetone: 0.1%, ethanol: 0.15%, dimethoxymethane: 0.01%, propylene oxide: 12%, and methanol: equilibrium.

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