Gas chromatographic analysis method and device for perfluoro-n-propyl vinyl ether

Abstract

The invention relates to a gas chromatographic analysis method and a gas chromatographic analysis device for perfluoro-n-propyl vinyl ether. The method provided by the invention comprises the following steps: S1, injecting a perfluoro-n-propyl vinyl ether sample of which the temperature is lower than 10 DEG C into a vaporizing chamber from a sample inlet, and vaporizing; S2, enabling the vaporized sample to sequentially pass through a chromatographic column A and a chromatographic column B which are connected in series under the carrying of carrier gas; s3, performing quantitative analysis on data detected by the detector; wherein the chromatographic column A is used for separating hydrogen-containing impurities in the perfluoro-n-propyl vinyl ether; the chromatographic column B is used for separating the perfluoro impurities in the perfluoro-n-propyl vinyl ether; the sample inlet adopts a temperature programming mode, and the chromatographic column A and the chromatographic column B adopt a multi-stage temperature programming mode. According to the invention, through the mode of temperature programming at the sample inlet and serial connection of the chromatographic columns, various different types of impurities are separated through different types of chromatographic columns, so that the accuracy and stability of testing are effectively improved.

Description

Technical Field

[0001] The present application relates to the field of analytical technology, and in particular to a gas chromatography analysis method and device for perfluoro-n-propyl vinyl ether. Background Art

[0002] Perfluoro n-propyl vinyl ether (PPVE) is an important monomer in the polymerization production of fluorine materials and can be widely used in the production of various types of fluorine resins and fluorine rubber modified materials. In the production process of PPVE, different types of intermediates and by-products may be produced. Due to the strong oxidizing property of fluorine atoms, these intermediates are easily decomposed or converted into substances with other chemical structures. The presence of such substances, even in very small amounts, will greatly affect the use of PPVE in subsequent polymerization production, resulting in the obstruction of the polymerization reaction or changes in the performance of modified fluorine materials. Therefore, it is necessary to conduct purity tests on PPVE to ensure the stable development of production.

[0003] At present, the purity characterization of PPVE is mostly tested by gas chromatography. However, since PPVE has a variety of cracking and preparation methods to produce, different production processes will produce intermediates and by-products of different properties. The existing gas chromatography analysis method cannot separate all impurities, resulting in PPVE that meets the chromatographic purity standard still being hindered by the presence of impurities during the polymerization process, and does not actually play a role in chemical quality control.

[0004] Therefore, it is necessary to propose a gas chromatography quantitative method for perfluoro-n-propyl vinyl ether. Summary of the invention

[0005] In order to solve the above technical problems existing in the prior art, the present application provides an analysis method for perfluoro-n-propyl vinyl ether. The method provided in the present application aims at the technical difficulties of separating multiple types of impurities in the purity detection of perfluoro-n-propyl vinyl ether. On the basis of the prior art, the method uses the method of program heating of the injection port and serial connection of chromatographic columns to separate various types of impurities through different types of chromatographic columns, thereby effectively improving the accuracy and stability of the test.

[0006] In a first aspect, the present application provides a gas chromatography analysis method for perfluoro-n-propyl vinyl ether, comprising the following steps:

[0007] S1: Inject the perfluoro-n-propyl vinyl ether sample below 10°C into the vaporization chamber through the injection port for vaporization.

[0008] S2: The vaporized sample is carried by the carrier gas and sequentially passes through the chromatographic columns A and B connected in series;

[0009] S3: Quantitatively analyze the data detected by the detector;

[0010] Among them, the chromatographic column A is used to separate hydrogen-containing impurities in perfluoro-n-propyl vinyl ether; the chromatographic column B is used to separate perfluorinated impurities in perfluoro-n-propyl vinyl ether; the injection port adopts a programmed temperature rising method, and the chromatographic columns A and B adopt a step-programmed temperature rising method.

[0011] In some embodiments, chromatographic column A and chromatographic column B are selected from capillary chromatographic columns.

[0012] In some embodiments, the chromatographic column A is selected from a medium polarity chromatographic column. In some embodiments, the stationary phase of the chromatographic column A is cyanopropylbenzene and dimethylsiloxane. In some embodiments, the stationary phase of the chromatographic column A is 6% cyanopropylbenzene and 94% dimethylsiloxane.

[0013] In some embodiments, the length of chromatographic column A is 20m-60m (for example, 25m, 30m, 35m, 40m, 45m, 50m or 55m), the inner diameter is 0.18mm-0.32mm (for example, 0.2mm, 0.23mm, 0.25mm, 0.27mm or 0.3mm), and the film thickness is 1.0μm-1.8μm (for example, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm or 1.7μm).

[0014] In some embodiments, the chromatographic column A is an Agilent DB-624 chromatographic column.

[0015] In some embodiments, the chromatographic column A has a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.4 μm.

[0016] In some embodiments, the chromatographic column B is selected from polar chromatographic columns. In some embodiments, the stationary phase of the chromatographic column B is trifluoropropyl and dimethylsiloxane. In some embodiments, the stationary phase of the chromatographic column B is 12% trifluoropropyl and 88% dimethylsiloxane.

[0017] In some embodiments, the length of chromatographic column B is 15m-60m (for example, 20m, 25m, 30m, 35m, 40m, 45m, 50m or 55m), the inner diameter is 0.15mm-0.53mm (for example, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm or 0.5mm), and the film thickness is 0.1μm-1.0μm (for example, 0.15μm, 0.25μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, 0.55μm, 0.6μm, 0.65μm, 0.7μm, 0.75μm, 0.8μm, 0.85μm or 0.9μm).

[0018] In some embodiments, the chromatographic column B is an Agilent VF-200ms chromatographic column.

[0019] In some embodiments, the chromatographic column B has a length of 15 m, an inner diameter of 0.25 mm, and a film thickness of 0.5 μm.

[0020] In some embodiments, the temperature of the perfluoro-n-propyl vinyl ether sample is -18°C to 10°C, for example, -15°C, -13°C, -10°C, -9°C, -8°C, -7°C, -6°C, -5°C, -4°C, -3°C, -2°C, -1°C, 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 7°C or any value therebetween. In some embodiments, the temperature of the perfluoro-n-propyl vinyl ether sample is -10°C to 0°C. When the temperature of the perfluoro-n-propyl vinyl ether sample is too high, the impurities with lower boiling points evaporate into the air and fail to enter the chromatographic system for separation and analysis, which will lead to a decrease in the accuracy of the analysis.

[0021] In some embodiments, the injection needle for injecting the perfluoro-n-propyl vinyl ether sample needs to be refrigerated at -18°C to 10°C (for example, -15°C, -13°C, -10°C, -9°C, -8°C, -7°C, -6°C, -5°C, -4°C, -3°C, -2°C, -1°C, 0°C, 1°C, 2°C, 3°C, 4°C, 5°C or 7°C) for more than 10 min.

[0022] In some embodiments, the temperature program in the injection port is maintained at 25±2°C for 0.1min-1min, such as 0.2min, 0.3min, 0.4min, 0.5min, 0.6min, 0.7min, 0.8min or 0.9min, and then the temperature is increased to 230±10°C at a rate of 100±10°C / min. In some embodiments, the heating rate is 91°C / min, 92°C / min, 93°C / min, 94°C / min, 95°C / min, 96°C / min, 97°C / min, 98°C / min, 99°C / min, 100°C / min, 101°C / min, 102°C / min, 103°C / min, 104°C / min, 105°C / min, 106°C / min, 107°C / min, 108°C / min, 109°C / min or any value therebetween. A too slow heating rate may lead to the loss or reaction of compound components, and all components may not be brought into the chromatographic column in time. A too fast heating rate may cause excessive loss to the instrument. In some embodiments, the program heating method in the injection port is to maintain the temperature at 25°C for 0.2 min, then increase the temperature to 230°C at a rate of 100°C / min, and maintain at this temperature until the end of the test.

[0023] In some embodiments, the multi-stage programmed temperature heating method in the chromatographic column A is as follows: after maintaining at 40±2°C for 3-7min (e.g., 4min, 5min, or 6min), the temperature is increased to 70°C / min at a rate of 10°C / min to 20°C / min (e.g., 11°C / min, 12°C / min, 13°C / min, 14°C / min, 15°C / min, 16°C / min, 17°C / min, 18°C / min, or 19°C / min), and maintained for 1min-5min; the temperature is increased to 150±2°C at a rate of 10°C / min-35°C / min (e.g., 13°C / min, 15°C / min, 17°C / min, 20°C / min, 23°C / min, 25°C / min, 27°C / min, 30°C / min, or 33°C / min), and maintained for 1min-5min (e.g., 2min, 3min, or 4min).

[0024] In some embodiments, the multi-stage programmed temperature rise method in the chromatographic column A is to maintain at 40°C for 5 minutes, then increase the temperature to 70°C at a rate of 10-20°C / min and maintain for 2-5 minutes, and then increase the temperature to 150°C at a rate of 10-35°C / min and maintain at this temperature for 1-5 minutes.

[0025] In some embodiments, the multi-stage programmed temperature heating method in the chromatographic column B is as follows: after maintaining at 40±2°C for 3-7min (e.g., 4min, 5min, or 6min), the temperature is increased to 70°C / min at a rate of 10°C / min to 20°C / min (e.g., 11°C / min, 12°C / min, 13°C / min, 14°C / min, 15°C / min, 16°C / min, 17°C / min, 18°C / min, or 19°C / min) and maintained for 1min-5min, the temperature is increased to 150±2°C at a rate of 10°C / min-35°C / min and maintained for 1min-5min.

[0026] In some embodiments, the multi-stage programmed temperature heating method in the chromatographic column B is as follows: after maintaining at 40°C for 5 min, the temperature is increased to 70°C at a rate of 10-20°C / min and maintained for 2-5 min, the temperature is increased to 150°C at a rate of 10-35°C / min (e.g., 13°C / min, 15°C / min, 17°C / min, 20°C / min, 23°C / min, 25°C / min, 27°C / min, 30°C / min or 33°C / min), and maintained at this temperature for 1-5 min (e.g., 2 min, 3 min or 4 min).

[0027] In some embodiments, the injection volume of the perfluoro-n-propyl vinyl ether sample is 0.3 μL-2.5 μL. In some embodiments, the injection volume of the perfluoro-n-propyl vinyl ether sample is 0.4 μL, 0.5 μL, 0.6 μL, 0.7 μL, 0.8 μL, 0.9 μL, 1. μL, 1.1 μL, 1.2 μL, 1.3 μL, 1.5 μL, 1.7 μL, 2.0 μL, 2.3 μL or any value therebetween. In some embodiments, the injection volume of the perfluoro-n-propyl vinyl ether sample is 0.5 μL-1.5 μL. When the injection volume is too low, some trace impurities cannot be detected. When the injection volume is too large, the main content will be flat, and the impurity content will be relatively larger, which will affect the accuracy of the test.

[0028] In some embodiments, the split ratio is 50-90, such as 53, 57, 63, 67, 73, 77, 83 or any value therebetween. In some embodiments, the split ratio is 60-80.

[0029] In some embodiments, the initial temperature of the vaporization chamber is set to 15° C.-25° C. and maintained for 10 min-20 min.

[0030] In some embodiments, the carrier gas is high-purity nitrogen (99.999% or more), and the gas flow rate of the carrier gas is 1-2 mL / min.

[0031] In some embodiments, the detector is selected from a hydrogen flame detector, and the temperature of the detector is 300±5°C.

[0032] In some embodiments, in step S3, the integrated area normalization method is used for quantitative analysis.

[0033] In some embodiments, the collected gas chromatogram is normalized by integrated area, and the purity of perfluoro-n-propyl vinyl ether is:

[0034] PPVE%=S PPVE / ∑S (1)

[0035] Where: S PPVE is the peak area of ​​perfluoro-n-propyl vinyl ether, ∑S is the total area of ​​all peaks

[0036] In some embodiments, the analysis method comprises the following specific steps:

[0037] 1.1 Set the injection port program: set the initial temperature of the vaporization chamber to 15-25°C, maintain it for 10-20 minutes, set the split ratio to 60-80, and the injection port temperature program is: maintain it at 25°C for 0.2 minutes, then increase the temperature to 230°C at a rate of 100°C / min, and maintain it at this temperature until the end of the test.

[0038] 1.2 Set the column oven program: keep at 40℃ for 5 minutes, then increase the temperature to 70℃ at a rate of 10-20℃ / min and keep it for 2-5 minutes, then increase the temperature to 150℃ at a rate of 10-35℃ / min and keep it at this temperature for 1-5 minutes.

[0039] 1.3 Carrier gas: Select high-purity nitrogen of 99.999% or above as the carrier gas, and the gas flow rate is 1.5ml / min.

[0040] 1.4 Set the detector parameters: the detector is a hydrogen flame detector (FID), the temperature is 300°C, the air (fuel) flow rate is 400ml / min, the hydrogen (fuel) flow rate is 30ml / min, and the nitrogen (tail gas) flow rate is 25ml / min.

[0041] 1.5 Injection: Before injection, refrigerate the injection needle at -18 to 10°C for more than 10 minutes, use the injection needle to take 0.5 to 1.5 μL of perfluoro-n-propyl vinyl ether sample, and quickly inject it into the injection port. The sample is carried by the carrier gas through chromatographic columns A and B, and the detected substances are subjected to gas chromatography quantitative analysis.

[0042] 1.6 Analysis and calculation: The integrated area normalization method was used for the collected gas chromatogram, and the purity of perfluoro-n-propyl vinyl ether was:

[0043] PPVE%=S PPVE / ∑S (1)

[0044] Where: S PPVE is the peak area of ​​perfluoro-n-propyl vinyl ether, and ∑S is the total area of ​​all peaks.

[0045] In a second aspect, the present application provides a gas chromatography analysis device for the analysis method described in the first aspect, which includes an injection device, a chromatographic column A, a chromatographic column B and a detector, wherein the injection port of the injection device is connected to the inlet of the chromatographic column A, the outlet of the chromatographic column A is connected to the inlet of the chromatographic column B, and the outlet of the chromatographic column B is connected to the detector.

[0046] Beneficial technical effects of this application:

[0047] In the existing purity test method of perfluoro-n-propyl vinyl ether, due to the different production processes, intermediates and by-products of different polarities are produced. The traditional single gas chromatography analysis method cannot separate all impurities, and the analysis and testing process cannot actually play a role in chemical quality control. The method described in the present invention can solve the above problems and achieve the purpose of accurate qualitative detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1The gas chromatogram of the PPVE sample obtained by the analysis method of Example 1;

[0049] Figure 2 The gas chromatogram of the PPVE sample obtained by the analysis method of Example 2;

[0050] Figure 3 The gas chromatogram of the PPVE sample obtained by the analysis method of Example 3;

[0051] Figure 4 The gas chromatogram of the PPVE sample obtained by the analysis method of Comparative Example 1;

[0052] Figure 5 The gas chromatogram of the PPVE sample obtained by the analysis method of Comparative Example 2;

[0053] Figure 6 The gas chromatogram of the PPVE sample obtained by the analysis method of Comparative Example 3;

[0054] Figure 7 The gas chromatogram of the PPVE sample obtained by the analysis method of Comparative Example 4;

[0055] Figure 8 The gas chromatogram of the PPVE sample obtained by the analysis method of Comparative Example 5 is shown in FIG. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and drawings. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation to the present invention.

[0057] Example 1: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer A

[0058] Agilent 8890 chromatograph was used, and column A was selected as Agilent DB-624 column, with a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.4 μm; column B was selected as Agilent VF-200ms column, with a length of 15 m, an inner diameter of 0.25 mm, and a film thickness of 0.5 μm. The gas chromatograph inlet was sealed and connected to the inlet end of column A, the outlet of column A was connected in series with the inlet of column B, and the outlet of column B was sealed and connected to the FID detector.

[0059] Analytical methods:

[0060] The initial temperature of the vaporization chamber was set to 25°C and maintained for 20 min. The split ratio was set to 72. The injection port temperature program was set as follows: after maintaining at 25°C for 0.2 min, the temperature was increased to 230°C at a rate of 100°C / min and maintained at this temperature until the end of the test.

[0061] Set the column oven program: keep at 40℃ for 5 minutes, then heat to 70℃ at a rate of 20℃ / min and keep for 3 minutes, then heat to 150℃ at a rate of 35℃ / min and keep at this temperature for 2 minutes. Select high-purity nitrogen as the carrier gas, and the gas flow rate is 1.5ml / min.

[0062] Set the FID detector temperature to 300°C, the air flow rate to 400 ml / min, the hydrogen flow rate to 30 ml / min, and the nitrogen flow rate to 25 ml / min.

[0063] The injection needle was refrigerated at -4°C for 10 min, and 0.5 μL of perfluoro-n-propyl vinyl ether sample was quickly injected into the injection port. After the spectrum was collected, the purity of PPVE was calculated according to formula (1):

[0064] PPVE%=S PPVE / ∑S formula (1)

[0065] Where: S PPVE is the peak area of ​​perfluoro-n-propyl vinyl ether, and ∑S is the total area of ​​all peaks.

[0066] like Figure 1 As shown, the peak with a retention time of 4.23 min is perfluoro-n-propyl vinyl ether, with a purity of 95.436% and 27 impurity types. Observing the spectrum, the peak is sharp and not flat-topped, and the number of impurity peaks is large and clearly separated.

[0067] The sample was measured 7 times in succession according to this method and the purity was compared. The results are shown in Table 1.

[0068] Table 1 Data and deviation calculation of 7 consecutive tests on samples of manufacturer A according to the method

[0069]

[0070] It can be seen from the data results in Table 1 that the method of the present invention can obtain relatively stable analysis results.

[0071] Example 2: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer B

[0072] Agilent 8890 chromatograph was used, and column A was selected as Agilent DB-624 column, with a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.4 μm; column B was selected as Agilent VF-200ms column, with a length of 15 m, an inner diameter of 0.25 mm, and a film thickness of 0.5 μm. The gas chromatograph inlet was sealed and connected to the inlet end of column A, the outlet of column A was connected in series with the inlet of column B, and the outlet of column B was sealed and connected to the FID detector.

[0073] Analytical methods:

[0074] The initial temperature of the vaporization chamber was set to 25°C and maintained for 20 min. The split ratio was set to 72. The injection port temperature program was set as follows: after maintaining at 25°C for 0.2 min, the temperature was increased to 230°C at a rate of 100°C / min and maintained at this temperature until the end of the test.

[0075] Set the column oven program: keep at 40℃ for 5 minutes, then heat to 70℃ at a rate of 20℃ / min and keep for 3 minutes, then heat to 150℃ at a rate of 35℃ / min and keep at this temperature for 2 minutes. Select high-purity nitrogen as the carrier gas, and the gas flow rate is 1.5ml / min.

[0076] Set the FID detector temperature to 300°C, the air flow rate to 400 ml / min, the hydrogen flow rate to 30 ml / min, and the nitrogen flow rate to 25 ml / min.

[0077] The injection needle was refrigerated at -4°C for 10 min, and 0.5 μL of perfluoro-n-propyl vinyl ether sample was quickly injected into the injection port. After the spectrum was collected, the purity of PPVE was calculated according to formula (1) in the same way as in Example 1.

[0078] like Figure 2 As shown, the peak with a retention time of 4.23 min is perfluoro-n-propyl vinyl ether, the purity of perfluoro-n-propyl vinyl ether is 99.793%, and there are 22 impurity types.

[0079] Although the sample produced by manufacturer B has high purity, it reacts slowly in the subsequent polymerization process and the product properties are not ideal. It is speculated that the reason is that there are many types of impurities inside it. Some impurities with special properties, even if the content is extremely low, will also affect the subsequent reaction process and need to be removed in the subsequent process. This also further shows that the method described in the present invention can successfully separate the impurities in the pure material and can play a role in quality monitoring of raw materials in actual production applications.

[0080] Example 3: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer C

[0081] Agilent 8890 chromatograph was used, and column A was selected as Agilent DB-624 column, with a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.4 μm; column B was selected as Agilent VF-200ms column, with a length of 15 m, an inner diameter of 0.25 mm, and a film thickness of 0.5 μm. The gas chromatograph inlet was sealed and connected to the inlet end of column A, the outlet of column A was connected in series with the inlet of column B, and the outlet of column B was sealed and connected to the FID detector.

[0082] Analytical methods:

[0083] The initial temperature of the vaporization chamber was set to 25°C and maintained for 20 min. The split ratio was set to 72. The injection port temperature program was set as follows: after maintaining at 25°C for 0.2 min, the temperature was increased to 230°C at a rate of 100°C / min and maintained at this temperature until the end of the test.

[0084] Set the column oven program: keep at 40℃ for 5 minutes, then heat to 70℃ at a rate of 20℃ / min and keep for 3 minutes, then heat to 150℃ at a rate of 35℃ / min and keep at this temperature for 2 minutes. Select high-purity nitrogen as the carrier gas, and the gas flow rate is 1.5ml / min.

[0085] Set the FID detector temperature to 300°C, the air flow rate to 400 ml / min, the hydrogen flow rate to 30 ml / min, and the nitrogen flow rate to 25 ml / min.

[0086] The injection needle was refrigerated at -4°C for 10 min, and 0.5 μL of perfluoro-n-propyl vinyl ether sample was quickly injected into the injection port. After the spectrum was collected, the purity of PPVE was calculated according to formula (1) in the same way as in Example 1.

[0087] like Figure 3 As shown, the peak with a retention time of 4.23 min is perfluoro-n-propyl vinyl ether, the purity of which is 99.519%, and there are 10 impurity types.

[0088] Although the purity of the samples produced by Manufacturer C is not as high as that of the products produced by Manufacturer B, it has fewer types of impurities, reacts quickly and stably in the subsequent polymerization process, and has excellent product performance, indicating that the impurities present therein will hardly affect the subsequent polymerization reaction. As long as the impurity content is controlled within this level, the subsequent reaction process can proceed smoothly.

[0089] Example 4: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer A

[0090] Agilent 8890 chromatograph was used, and column A was selected as Agilent DB-624 column, with a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.4 μm; column B was selected as Agilent VF-200ms column, with a length of 15 m, an inner diameter of 0.25 mm, and a film thickness of 0.5 μm. The gas chromatograph inlet was sealed and connected to the inlet end of column A, the outlet of column A was connected in series with the inlet of column B, and the outlet of column B was sealed and connected to the FID detector.

[0091] Analytical methods:

[0092] The initial temperature of the vaporization chamber was set to 25°C and maintained for 20 min. The split ratio was set to 72. The injection port temperature program was set as follows: after maintaining at 25°C for 0.2 min, the temperature was increased to 230°C at a rate of 100°C / min and maintained at this temperature until the end of the test.

[0093] Set the column oven program: keep at 40℃ for 5 minutes, then heat to 70℃ at a rate of 20℃ / min and keep for 3 minutes, then heat to 150℃ at a rate of 35℃ / min and keep at this temperature for 2 minutes. Select high-purity nitrogen as the carrier gas, and the gas flow rate is 1.5ml / min.

[0094] Set the FID detector temperature to 300°C, the air flow rate to 400 ml / min, the hydrogen flow rate to 30 ml / min, and the nitrogen flow rate to 25 ml / min.

[0095] The injection needle was refrigerated at -4°C for 10 min, and 0.3 μL, 1.0 μL, 1.5 μL, 2.0 μL, and 2.5 μL of the perfluoro-n-propyl vinyl ether sample were taken and quickly injected into the injection port, and after the spectrum acquisition was completed, the PPVE purity was calculated according to formula (1) in the same way as in Example 1. The purity and impurity results measured with different injection amounts are shown in Table 2 below.

[0096] Table 2 PPVE results of manufacturer A measured with different injection volumes

[0097] Injection volume 0.3μL 1μL 1.5μL 2μL 2.5μL purity 95.936％ 95.422％ 95.429％ 92.331％ 86.293％ Impurity quantity 22 types 27 types 27 types 27 types 27 types

[0098] It can be seen from Table 2 that the data of 1.0μL and 1.5μL injection volume have little deviation from the data of 0.5μL injection volume. When the injection volume is less than 0.5μL, some trace impurities cannot be detected, so its purity is greater than 0.5μL. When the injection volume is greater than 1.5μL, the main content will be flat and the impurity content will be relatively larger, so its purity is less than 0.5μL.

[0099] Example 5: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer A

[0100] Agilent 8890 chromatograph was used, and column A was selected as Agilent DB-624 column, with a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.4 μm; column B was selected as Agilent VF-200ms column, with a length of 15 m, an inner diameter of 0.25 mm, and a film thickness of 0.5 μm. The gas chromatograph inlet was sealed and connected to the inlet end of column A, the outlet of column A was connected in series with the inlet of column B, and the outlet of column B was sealed and connected to the FID detector.

[0101] Analytical methods:

[0102] The initial temperature of the vaporization chamber was set to 25°C and maintained for 20 min. The split ratios were set to 60, 65, 70, 75, and 80, respectively. The injection port temperature program was set as follows: after maintaining at 25°C for 0.2 min, the temperature was increased to 230°C at a rate of 100°C / min and maintained at this temperature until the end of the test.

[0103] Set the column oven program: keep at 40℃ for 5 minutes, then heat to 70℃ at a rate of 20℃ / min and keep for 3 minutes, then heat to 150℃ at a rate of 35℃ / min and keep at this temperature for 2 minutes. Select high-purity nitrogen as the carrier gas, and the gas flow rate is 1.5ml / min.

[0104] Set the FID detector temperature to 300°C, the air flow rate to 400 ml / min, the hydrogen flow rate to 30 ml / min, and the nitrogen flow rate to 25 ml / min.

[0105] The injection needle was refrigerated at -4°C for 10 min, 0.5 μL of the perfluoro-n-propyl vinyl ether sample was quickly injected into the injection port, and after the spectrum was collected, the PPVE purity was calculated according to formula (1) in the same manner as in Example 1. The purity results measured at different split ratios are shown in Table 3 below.

[0106] Table 3 PPVE results of manufacturer A at different split ratios

[0107] Split Ratio 50 60 70 80 90 purity 94.303％ 95.429％ 95.439％ 95.444％ 95.897％ Impurity quantity 27 types 27 types 27 types 27 types 25 types

[0108] It can be seen from Table 3 that the purity data of split ratios of 60, 70, and 80 deviate very little from the data of split ratio of 72. When the split ratio is greater than 80, some trace impurities cannot be detected, so its purity is greater than the split ratio of 72. When the split ratio is less than 60, the main content will be flat and the impurity content will be relatively higher, so its purity is smaller than the split ratio of 72.

[0109] Example 6: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer A

[0110] Agilent 8890 chromatograph was used, and column A was selected as Agilent DB-624 column, with a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.4 μm; column B was selected as Agilent VF-200ms column, with a length of 15 m, an inner diameter of 0.25 mm, and a film thickness of 0.5 μm. The gas chromatograph inlet was sealed and connected to the inlet end of column A, the outlet of column A was connected in series with the inlet of column B, and the outlet of column B was sealed and connected to the FID detector.

[0111] Analytical methods:

[0112] Set the initial temperature of the vaporization chamber to 25°C, maintain it for 20 min, set the split ratio to 72, and set the injection port temperature program as follows: maintain it at 25°C for 0.2 min, then increase the temperature to 230°C at rates of 60°C / min, 80°C / min, 120°C / min, and 140°C / min, and maintain it at this temperature until the end of the test.

[0113] Set the column oven program: keep at 40℃ for 5 minutes, then heat to 70℃ at a rate of 20℃ / min and keep for 3 minutes, then heat to 150℃ at a rate of 35℃ / min and keep at this temperature for 2 minutes. Select high-purity nitrogen as the carrier gas, and the gas flow rate is 1.5ml / min.

[0114] Set the FID detector temperature to 300°C, the air flow rate to 400 ml / min, the hydrogen flow rate to 30 ml / min, and the nitrogen flow rate to 25 ml / min.

[0115] The injection needle was refrigerated at -4°C for 10 min, 0.5 μL of the perfluoro-n-propyl vinyl ether sample was quickly injected into the injection port, and after the spectrum was collected, the PPVE purity was calculated according to formula (1) in the same manner as in Example 1. The purity results measured at different injection port heating rates are shown in Table 4 below.

[0116] Table 4 PPVE results produced by manufacturer A measured at different heating rates

[0117] Inlet heating rate 60℃ / min 80℃ / min 120℃ / min 140℃ / min purity 95.368％ 95.427％ 95.436％ 95.428％ Impurity quantity 26 types 27 types 27 types 27 types

[0118] If the heating rate is too slow, it will lead to the loss or reaction of compound components, and all components cannot be brought into the chromatographic column in time. If the heating rate is too fast, the instrument may not be able to reach it.

[0119] Comparative Example 1: Analysis of the purity of perfluoro n-propyl vinyl ether produced by manufacturer A

[0120] This comparative example provides a method for the purity of perfluoro-n-propyl vinyl ether, which differs from Example 1 only in that a single universal chromatographic column (Agilent DB-5 chromatographic column 60m×0.32mm×0.5μm) is connected to a chromatographic analysis system, and columns A and B are removed for analysis.

[0121] like Figure 4 As shown in the figure, the peak with a retention time of 5.06 min is perfluoro-n-propyl vinyl ether, and its purity is 100%, and impurities cannot be separated. This shows that the general weak polarity chromatographic column does not have the ability to separate PPVE impurity components.

[0122] Comparative Example 2: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer A

[0123] This comparative example provides a method for the purity of perfluoro-n-propyl vinyl ether, which is different from Example 1 only in that only chromatographic column A (Agilent DB-624 chromatographic column 60m×0.25mm×1.4μm) is connected to the chromatographic analysis system, and column B is removed for analysis.

[0124] like Figure 5 As shown, the peak with a retention time of 2.19 min is perfluoro-n-propyl vinyl ether, with a purity of 99.842% and 17 impurity types, indicating that a single chromatographic column cannot separate all impurity components.

[0125] Comparative Example 3: Analysis of the purity of perfluoro n-propyl vinyl ether produced by manufacturer A

[0126] This comparative example provides a method for the purity of perfluoro-n-propyl vinyl ether, which differs from Example 1 only in that only chromatographic column B (Agilent VF-200ms chromatographic column, 60m×0.25mm×0.5μm) is connected to the chromatographic analysis system, and column A is removed for analysis.

[0127] like Figure 6 As shown, the peak with a retention time of 3.81 min is perfluoro-n-propyl vinyl ether, with a purity of 99.576% and 10 impurity types, indicating that a single chromatographic column cannot separate all impurity components.

[0128] Comparative Example 4: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer A

[0129] This comparative example provides a method for the purity of perfluoro-n-propyl vinyl ether, which is different from Example 1 only in that the injection needle is not frozen, and 0.5 μL is directly taken out and quickly injected into the injection port for analysis after being placed at room temperature.

[0130] like Figure 7 As shown in the figure, the peak with a retention time of 4.23 min is perfluoro-n-propyl vinyl ether, with a purity of 99.845% and 6 impurity types. The purity is higher than the true value, and the number of impurity types separated is reduced by 21. This is because the impurities have extremely low boiling points. When sampling with a normal temperature sampling needle, these impurities with extremely low boiling points evaporate into the air and fail to enter the chromatographic system for separation and analysis.

[0131] Comparative Example 5: Analysis of the purity of perfluoro n-propyl vinyl ether produced by manufacturer A

[0132] This comparative example provides a method for improving the purity of perfluoro-n-propyl vinyl ether, which is different from Example 1 only in that the temperature of the vaporization chamber is kept constant at 230°C.

[0133] like Figure 8 As shown in the figure, the peak with a retention time of 3.456 min is perfluoro-n-propyl vinyl ether, with a purity of 99.466% and 12 impurity types. The purity is close to the true value, but the number of impurity types separated is reduced by 15, and most of the impurities have a very similar retention time to the main peak of PPVE, which cannot play the role of separating and identifying different impurities. This is because when the vaporization chamber is not programmed to heat up, substances with similar boiling points enter the chromatographic column at the same time. When their polarities are similar, their retention times in the column are also similar, which will cause some impurity peaks to stick together and cannot be effectively separated.

[0134] Comparative Example 6: Analysis of the purity of perfluoro-n-propyl vinyl ether produced by manufacturer A

[0135] This comparative example provides a method for the purity of perfluoro-n-propyl vinyl ether, which differs from Example 1 only in that the column oven temperature program is: 40°C is the initial temperature and is not maintained, and the temperature is directly increased to 150°C at a rate of 10°C / min and maintained at this temperature for 5 minutes.

[0136] The purity of the perfluoro-n-propyl vinyl ether in the sample tested was 99.493%, and there were 18 impurity types. The purity was close to the true value, but the number of impurity types separated was reduced by 8. This was because the chromatographic column heated up too quickly, and impurities with slight differences in boiling points could not be separated from each other in the column, resulting in the adhesion of impurity peaks and ineffective separation.

[0137] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A gas chromatography analysis method for perfluoro-n-propyl vinyl ether, comprising the following steps: S1: Inject the perfluoro-n-propyl vinyl ether sample below 10°C into the vaporization chamber through the injection port for vaporization. S2: The vaporized sample is carried by the carrier gas and sequentially passes through the chromatographic columns A and B connected in series; S3: Quantitatively analyze the data detected by the detector; Among them, the chromatographic column A is used to separate hydrogen-containing impurities in perfluoro-n-propyl vinyl ether; the chromatographic column B is used to separate perfluorinated impurities in perfluoro-n-propyl vinyl ether; the injection port adopts a programmed temperature heating method, and the chromatographic columns A and B adopt a multi-stage programmed temperature heating method.

2. The analysis method according to claim 1, characterized in that The chromatographic column A is selected from a medium polarity chromatographic column. Preferably, the stationary phase of the chromatographic column A is cyanopropylbenzene and dimethylsiloxane, for example, 6% cyanopropylbenzene and 94% dimethylsiloxane. More preferably, the length of the chromatographic column A is 20m-60m, the inner diameter is 0.18mm-0.32mm, and the film thickness is 1.0μm-1.8μm. Further preferably, the length of the chromatographic column A is 30m, the inner diameter is 0.25mm, and the film thickness is 1.4μm; and / or The chromatographic column B is selected from a polar chromatographic column. Preferably, the stationary phase of the chromatographic column B is trifluoropropyl and dimethylsiloxane, for example, 12% trifluoropropyl and 88% dimethylsiloxane. More preferably, the length of the chromatographic column B is 15m-60m, the inner diameter is 0.15mm-0.53mm, and the film thickness is 0.1μm-1.0μm. Further preferably, the length of the chromatographic column B is 15m, the inner diameter is 0.25mm, and the film thickness is 0.5μm.

3. The analysis method according to claim 1 or 2, characterized in that The temperature of the perfluoro-n-propyl vinyl ether sample is -18°C to 10°C, preferably -10°C to 0°C.

4. The analysis method according to any one of claims 1 to 3, characterized in that The temperature program in the injection port is to maintain 25±2℃ for 0.1min-1min, and then increase the temperature to 230±10℃ at a rate of 100±10℃ / min.

5. The analysis method according to any one of claims 1 to 4, characterized in that The multi-stage programmed temperature rising method in the chromatographic column A and the chromatographic column B is to maintain at 40±2°C for 3-7 minutes, then increase the temperature to 70°C / min at a rate of 10°C / min to 20°C / min and maintain for 1min-5min, and then increase the temperature to 150±2°C at a rate of 10°C / min-35°C / min and maintain for 1min-5min.

6. The analysis method according to any one of claims 1 to 5, characterized in that The injection volume of the perfluoro-n-propyl vinyl ether sample is 0.3 μL-2.5 μL, preferably 0.5 μL-1.5 μL.

7. The analysis method according to any one of claims 1 to 6, characterized in that The split ratio is 50-90, preferably 60-80.

8. The analysis method according to any one of claims 1 to 7, characterized in that The carrier gas is high-purity nitrogen, and the gas flow rate of the carrier gas is 1-2 mL / min; and / or The detector is selected from a hydrogen flame detector, and the temperature of the detector is 300±5°C.

9. The analysis method according to any one of claims 1 to 8, characterized in that In step S3, the integrated area normalization method is used for quantitative analysis.

10. A gas chromatography analysis device for the analysis method according to any one of claims 1 to 9, comprising an injection device, a chromatographic column A, a chromatographic column B and a detector, wherein the injection port of the injection device is connected to the inlet of the chromatographic column A, the outlet of the chromatographic column A is connected to the inlet of the chromatographic column B, and the outlet of the chromatographic column B is connected to the detector.

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