Sample bin, device and method for liquid vacuum Raman spectrum test

Abstract

The invention provides a sample bin, a device and a method for vacuum Raman spectrum testing of liquid. According to the sample bin disclosed by the invention, the liquid Raman spectrum test from the liquid nitrogen temperature to the room temperature in a vacuum state is realized. And not only is the variable-temperature liquid Raman spectrum test from the liquid nitrogen temperature to the room temperature realized, but also the Raman spectrum test of a liquid sample with relatively strong volatility, such as ethanol and the like, is realized. In addition, liquor and other liquids react with metal, and the sample bin made of silica quartz can avoid the reaction, so that unstable samples such as liquor and the like are tested. The sample bin is not only suitable for 77K-298K variable-temperature Raman spectrum testing, but also capable of conducting heatable variable-temperature Raman spectrum testing at the temperature above the room temperature, and the specific testable temperature range is influenced by the boiling point of liquid, but is not limited by instruments and devices.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of Raman spectroscopy, and particularly relates to a sample chamber suitable for vacuum Raman spectroscopy testing of low-temperature liquid, room-temperature liquid and / or heated liquid, a device and a method thereof. BACKGROUND

[0002] Raman spectroscopy is based on the Raman scattering effect, that is, the frequency of scattered photons changes after laser photons interact with a sample. By measuring the scattered spectrum of the sample after interaction with a laser light source, information about the structure, composition and vibration of the sample can be provided. Raman spectroscopy has the characteristics of non-destructive, fast and high sensitivity, and can realize the analysis of different samples such as solids and liquids. In order to study the phase transition and composition of materials, low-temperature testing has become an important technical means. However, current research focuses on low-temperature Raman testing of solid samples. This hinders the analysis of liquid samples. Therefore, providing a technology capable of testing liquid Raman spectroscopy at low temperature will help to solve a series of analysis problems of liquid samples.

[0003] Raman spectroscopy testing is commonly used for room temperature and variable temperature testing of solid samples. There are few low-temperature Raman spectroscopy tests for liquid samples. In the current prior art, some achieve low-temperature liquid Raman spectroscopy testing in capillaries or in quartz crucibles, and some achieve low-temperature liquid Raman spectroscopy testing on thin glass plates. Low-temperature liquid Raman spectroscopy testing is of great significance for studying the phase transition of liquid samples. Through low-temperature testing, changes in the composition, structure and chemical bonds of the sample can be obtained. However, there are some problems in the current low-temperature liquid Raman testing: for example, testing through a capillary is not conducive to the collection of optical signals because the wall of the capillary is round. For some highly volatile samples, the sample needs to be strictly controlled in a vacuum environment during testing to avoid sample damage due to volatilization, water absorption, air absorption, etc. However, the experimental environment of the low-temperature stage of the Linkam THMS600 currently used is not vacuum. So far, there is no device that can achieve low-temperature liquid Raman spectroscopy testing in a vacuum state.

[0004] Therefore, it is urgent to solve the above problems, such as whether a device suitable for low-temperature Raman spectroscopy testing of liquid samples, especially highly volatile samples, can be provided, how to achieve low-temperature liquid Raman spectroscopy testing at liquid nitrogen temperature, and how to obtain accurate Raman data for liquid samples with weak signals. SUMMARY

[0005] Therefore, the present application aims to overcome the defects in the prior art and provide a sample cell suitable for vacuum Raman spectrum testing of low-temperature liquid, room-temperature liquid and / or heated liquid, and a device and method thereof. Through the liquid sample cell of the present application, liquid Raman spectrum testing in a vacuum state from liquid nitrogen temperature to room temperature is achieved. Not only is temperature-variable liquid Raman spectrum testing from liquid nitrogen temperature to room temperature achieved to provide phase change information, but also is Raman spectrum testing of a liquid sample with strong volatility from liquid nitrogen temperature to room temperature achieved, such as ethanol and the like.

[0006] To achieve the above-mentioned purpose, the first aspect of the present application provides a sample cell for liquid vacuum Raman spectrum testing, comprising: a metal cover, an optical window, a sealing ring and a metal bottom support; wherein:

[0007] The inside of the sample cell is extruded and sealed by the sealing ring, and the optical window and the sealing ring are located in a space composed of the metal cover and the metal bottom support.

[0008] The sample cell according to the first aspect of the present application, wherein,

[0009] The optical window is two mutually parallel optical windows;

[0010] A sealing ring is arranged between the two mutually parallel optical windows; and / or

[0011] A sealing ring is arranged above and below the two mutually parallel optical windows.

[0012] The sample cell according to the first aspect of the present application, wherein,

[0013] The sample cell further comprises a sample cell arranged below the optical window; and / or

[0014] The sealing ring is a mutually parallel sealing ring arranged above and below the sample cell;

[0015] Preferably, the material of the sample cell is quartz glass, most preferably silica quartz glass.

[0016] The sample cell according to the first aspect of the present application, wherein,

[0017] A hole is arranged on the metal cover and the metal bottom support;

[0018] The transmittance of the optical window is > 95%, preferably > 97%, more preferably > 99%; and / or

[0019] When the sample cell is used for vacuum Raman spectrum testing of low-temperature liquid, the metal cover, the optical window, the sealing ring and the metal bottom support are all made of low-temperature resistant material;

[0020] Preferably, the lowest temperature tolerance of the low-temperature resistant material is ≥ 55 K, more preferably ≥ 70 K, most preferably ≥ 77 K; and / or

[0021] Preferably, the vacuum degree of the vacuum is 10 -6 Pa ~ 10 -4 Pa, more preferably 10 -5 Pa ~ 10 -4 Pa, most preferably 10 -5 Pa.

[0022] The sample chamber according to the first aspect of the present application, wherein,

[0023] The number of the sealing rings is 2-5, preferably 2-4, more preferably 2-3;

[0024] The material of the metal cover is copper, most preferably red copper;

[0025] The material of the metal bottom support is copper, most preferably red copper;

[0026] The material of the optical window is quartz glass, most preferably silica quartz glass; and / or

[0027] The material of the sealing ring is rubber or fluorine rubber.

[0028] The sample chamber according to the first aspect of the present application, wherein,

[0029] The metal cover and the metal bottom support are connected by a connecting component; and / or

[0030] The bottom of the metal bottom support further has a threaded structure;

[0031] Preferably, the connecting component is a screw;

[0032] More preferably,

[0033] The number of the screws is 3-6, preferably 4-5, most preferably 4; and / or

[0034] The material of the screw is copper, most preferably red copper.

[0035] The second aspect of the present application provides the use of the sample chamber according to the first aspect in the preparation of an apparatus for vacuum Raman spectrum testing of low-temperature liquid, room-temperature liquid, heated liquid and / or variable-temperature liquid.

[0036] The third aspect of the present application provides a low-temperature liquid vacuum Raman testing device, comprising: the sample chamber according to the first aspect and a low-temperature thermostat for maintaining a low-temperature testing environment;

[0037] Preferably, the sample chamber is fixed on the cryostat;

[0038] More preferably, the sample chamber is fixed on the cryostat through the threaded structure of the bottom of the metal base.

[0039] The fourth aspect of the present application provides a testing method of low-temperature liquid vacuum Raman spectrum, which comprises using the low-temperature liquid vacuum Raman testing device of the third aspect;

[0040] Preferably, the testing method comprises the following steps:

[0041] 1) placing a sample to be tested in the sample chamber, and then placing the sample chamber on the cryostat;

[0042] 2) vacuumizing and cooling the inside of the cryostat;

[0043] 3) testing low-temperature liquid vacuum Raman spectrum data;

[0044] More preferably,

[0045] The temperature of the cooling is ≥55K, preferably ≥70K, and most preferably ≥77K; and / or

[0046] The vacuum degree of the vacuum is 10 -6 Pa~10 -4 Pa, preferably 10 -5 Pa~10 -4 Pa, and most preferably 10 -5 Pa.

[0047] According to the testing method of the fourth aspect of the present application,

[0048] The step (1) further comprises: the metal base, the optical window and the metal cover are extruded and sealed by a sealing ring, and the metal cover is fixed; and / or

[0049] The step (3) further comprises: focusing a light spot on the surface of the sample to scan the Raman spectrum.

[0050] According to a specific embodiment, as Figure 2 shown in the figure, the sample chamber for low-temperature liquid Raman spectrum testing of the present application. The physical figure of this sample chamber is as Figure 2 (b). This sample chamber can withstand a low-temperature environment, and can ensure that the vacuum degree reaches 10 - 5 Pa order of magnitude after vacuumizing. The physical figure of the sample cell of this sample chamber is as Figure 2 (a). As Figure 2(c), the metal base, the sealing ring, the sample cell, the sealing ring, the optical window, the metal cover are installed in parallel from bottom to top. The inside is extruded by the sealing ring, and the top is installed by the copper cover. On the one hand, the design of the parallel optical window is conducive to the collection of optical signals, and on the other hand, the extrusion of the sealing ring protects the vacuum environment of the liquid sample from volatilization, adsorption and other factors. Finally, the bottom of the sample bin is reserved with threads, and the sample bin is fixed on the low-temperature thermostat to realize in-situ Raman spectrum test.

[0051] As shown in Figure 3 (a), the sample bin is installed in the low-temperature thermostat, and the experimental device diagram in the vacuum state. As shown in Figure 3 (b), (c) and (d), the device diagram for low-temperature liquid Raman test of the application is shown. In the experiment, the inside of the low-temperature thermostat is vacuumed by a mechanical pump and a molecular pump unit, and then cooled by liquid nitrogen. Since the temperature sensor is installed on the copper support for fixing the sample, the accurate sample temperature can be obtained. As shown in Figure 4 , the Raman data of the liquid sample to be tested propylene carbonate + LiFSI (PC10 for short) detected by using the device of the application at room temperature and during the cooling process are shown, and compared with the reference data, only the Raman peaks near 400cm -1 and 1800cm -1 nearby have a small amount of shift and change during the cooling process, and the Raman peak near 700cm -1 is the main observed Raman peak of PC10, and the main Raman peak positions and intensities of the two correspond well. This provides experimental evidence that the experimental device designed by the application is suitable for liquid Raman spectrum test.

[0052] The use of the sample bin for liquid vacuum Raman spectrum test of the application is as follows:

[0053] (1) for variable-temperature liquid Raman spectrum test from liquid nitrogen temperature to room temperature;

[0054] (2) for maintaining a vacuum environment to avoid sample adsorption of air, moisture, etc.;

[0055] (3) for Raman spectrum test of volatile samples.

[0056] (4) The sample bin made of silica quartz glass has good stability, which is conducive to the preservation and test of wine and acid substances, and avoids the reaction of wine substances with metal.

[0057] (5) The application realizes liquid Raman spectrum test from liquid nitrogen temperature to room temperature in a vacuum state through the liquid sample bin (sample cell and optical window, sealed by the sealing ring inside).

[0058] The sample bin for liquid vacuum Raman spectrum test of the application can have, but is not limited to, the following

[0059] Advantages:

[0060] 1. The liquid Raman spectrum test at room temperature and liquid nitrogen temperature is realized, and the minimum temperature reaches 77K.

[0061] 2. The room temperature and low temperature liquid Raman test of liquid samples with strong volatility and easy air adsorption is realized, and the sample is ensured to be in a vacuum environment during the cooling process, and the vacuum degree reaches 10 -5 Pa.

[0062] 3. The room temperature and low temperature liquid Raman spectrum test of weak signal samples is realized.

[0063] 4. The Raman spectrum test of unstable and corrosive samples such as wine and acid is realized. BRIEF DESCRIPTION OF DRAWINGS

[0064] Hereinafter, the embodiments of the application will be described in detail with reference to the accompanying drawings, in which:

[0065] Figure 1 The structure diagram of the sample bin for low temperature liquid vacuum Raman spectrum test of the application in Example 1 is shown; wherein: Figure 1 (a) shows the liquid sample bin physical diagram; Figure 1 (b) shows the liquid sample bin structure schematic diagram; Figure 1 (c) shows the metal cover of the sample bin; Figure 1 (d) shows the sample bin metal bottom support.

[0066] Figure 2 The structure diagram of the sample bin for low temperature liquid vacuum Raman spectrum test of the application in Example 2 is shown; wherein: Figure 2 (a) shows the internal sample cell physical diagram; Figure 2 (b) shows the assembled sample bin schematic diagram; Figure 2 (c) shows the assembly details of the sample bin.

[0067] Figure 3 The experimental device for low temperature liquid vacuum Raman test is shown; wherein: Figure 3 (a) shows the liquid sample bin in a vacuum state; Figure 3 (b), (c) and (d) show the overall diagram of the experimental device for low temperature liquid Raman spectrum test.

[0068] Figure 4 The Raman spectrum data of the liquid sample to be tested, propylene carbonate + LiFSI (referred to as PC10), at room temperature and low temperature are shown; wherein: Figure 4(a) shows the Raman spectrum data of PC10 at room temperature using the device of the present application; Figure 4 (b) shows the Raman spectrum data of PC10 at room temperature for reference; Figure 4 (c) shows the variable-temperature Raman spectrum data of PC10 from room temperature to 77K; the above data are all carried out under vacuum degree 10 -5 Pa order of magnitude.

[0069] Figure 5 The Raman spectrum data of the liquid sample to be tested, propylene carbonate + LiFSI (PC10 for short), from room temperature to 77K are shown; wherein: Figure 5 (a) shows the Raman spectrum data of PC10 from room temperature to 77K using the device of the present application; the above data are all carried out under vacuum degree 10 -5 Pa order of magnitude. Figure 5 (b) shows the Raman spectrum data of PC10 at room temperature for reference.

[0070] Figure 6 The Raman spectrum data of ethanol are shown; wherein: Figure 6 (a) shows the Raman spectrum data of ethanol at room temperature for reference; Figure 6 (b) shows the Raman spectrum data of ethanol at room temperature, room temperature vacuum, 77K vacuum obtained by the sample chamber of Example 2.

[0071] BRIEF DESCRIPTION OF DRAWINGS

[0072] 1, metal cover; 2, optical window; 3, sealing ring; 4, metal bottom support; 5, sample cell. DETAILED DESCRIPTION

[0073] The present application will be further described in conjunction with the accompanying drawings and through specific examples, but it should be understood that these examples are only used for more detailed and specific illustration, and should not be understood as limiting the present application in any form.

[0074] This part generally describes the materials and test methods used in the test of the present application. Although many materials and operating methods used to achieve the purpose of the present application are well known in the art, the present application is described as much as possible. The skilled person in the art knows that, if not specifically stated, the materials and operating methods used in the present application are well known in the art.

[0075] Example 1

[0076] This example is an exemplary description of the sample chamber of the present application for liquid vacuum Raman spectrum test.

[0077] As Figure 1As shown in the embodiment described herein, one specific example of the sample cell for liquid vacuum Raman spectrum test includes a metal cover 1, two mutually parallel optical windows 2, a sealing ring 3 and a metal bottom holder 4. The interior of the sample cell is extruded and sealed by the sealing ring. The number of the sealing ring in the present application can be selected from 2 to 5, and the number used in the present embodiment is 3. The two mutually parallel optical windows are located in the space composed of the metal cover and the metal bottom holder. The metal cover and the metal bottom holder are both provided with holes for light transmission. The light transmittance of the two mutually parallel optical windows in the present application is 95%. The metal cover and the metal bottom holder are connected by the screw. The metal bottom holder is installed on the cryostat by screwing.

[0078] The metal cover, the two mutually parallel optical windows, the sealing ring and the metal bottom holder are all made of low-temperature-resistant materials. In the present embodiment, the material of the metal cover is red copper, the material of the two mutually parallel optical windows is silica quartz glass, the material of the sealing ring is rubber and / or fluorine rubber, and the material of the metal bottom holder is red copper.

[0079] The sample cell can withstand low-temperature environment and can ensure that the vacuum degree reaches 10 -5 Pa order of magnitude after being pumped. The sample cell retains the upper and lower optical windows, and the light transmittance of the optical windows is high enough. The interior is extruded by the sealing ring, and the upper part is installed by the cover made of red copper. On the one hand, the design of the upper and lower parallel optical windows is conducive to the collection of optical signals, and on the other hand, the extrusion of the sealing ring protects the vacuum environment of the liquid sample and is not affected by factors such as volatilization, adsorption and deterioration. Finally, the bottom of the sample cell is provided with threads, and the sample cell is fixed on the cryostat by threads to realize in-situ Raman spectrum test.

[0080] Example 2

[0081] The present embodiment is another exemplary description of the sample cell for liquid vacuum Raman spectrum test of the present application.

[0082] As Figure 2 shown in the present embodiment, the sample cell is used for low-temperature liquid vacuum Raman spectrum test, and the external structure is the same as that of embodiment 1, which is extruded and fixed by the metal cover 1 and the sealing ring 3. The metal bottom holder 4 is used for packaging the sample cell and is fixed on the cryostat. The sample cell includes a metal cover 1, an optical window 2, a sealing ring 3, a metal bottom holder 4 and a sample cell 5. Figure 2 (a) shows the sample cell, Figure 2 (b) shows the structure of the outside of the sample cell, Figure 2 (c) shows the structure of the inside of the sample cell, which adopts a stacking mode from bottom to top, i.e. the sealing ring 3, the silica quartz sample cell 5, the sealing ring 3 and the optical window 2.

[0083] The inside of the sample chamber is extruded and sealed by the sealing ring. The number of the sealing ring can be selected from 2 to 4, and the number used in the embodiment is 2. The optical window and the sample cell are located in the space composed of the metal cover and the metal bottom support. The metal cover is provided with a hole for light transmission. The transmittance of the two parallel optical windows is 95%. The metal cover and the metal bottom support are connected by the screw. The metal bottom support is installed on the cryostat by screw thread.

[0084] The metal cover, the optical window, the sealing ring, the sample cell and the metal bottom support are all made of low-temperature-resistant materials. In the embodiment, the material of the metal cover is red copper, the material of the optical window and the sample cell is silica quartz glass, the material of the sealing ring is fluorine glue, and the material of the metal bottom support is red copper.

[0085] The sample chamber can withstand a low-temperature environment, and the minimum temperature can reach 77K. After being pumped, the vacuum degree can reach 10 - 5 Pa order of magnitude. The sample chamber has one optical window and one sample cell, and the transmittance of the optical window is high enough. The inside is extruded and sealed by the sealing ring, and the top is installed by the copper cover. On the one hand, the design of the parallel optical window and the sample cell is conducive to the collection of optical signals, and on the other hand, the extrusion of the sealing ring protects the vacuum environment of the liquid sample and is not affected by factors such as volatilization, adsorption and deterioration. Finally, the bottom of the sample chamber is reserved with screw thread to fix the sample chamber on the cryostat, realizing in-situ Raman spectrum test.

[0086] Test Example 1

[0087] The test example is used to illustrate the implementation and effect of the sample chamber of the application for liquid vacuum Raman spectrum test at room temperature and low temperature.

[0088] The sample chamber of Example 1 is used in the test example to perform vacuum liquid Raman spectrum test on the liquid sample propylene carbonate+LiFSI (PC10 for short).

[0089] The liquid vacuum Raman spectrum test method comprises the following steps

[0090] 1) Place the sample to be tested in the sample chamber, and then place the sample chamber on the cryostat;

[0091] 2) When testing at low temperature, the inside is pumped and cooled; when testing at room temperature, for the sample PC10 with good stability, pumping and cooling are not required;

[0092] 3) Test liquid vacuum Raman spectrum data, focus the light spot on the sample surface by the microscopic confocal system (10X and 50X objective lens), excite by 532nm light, collect Raman spectrum data by iHR550 grating spectrometer. Before cooling, use mechanical pump and molecular pump to pump the sample environment to vacuum, then connect the liquid nitrogen tank to the cryostat by the infusion rod, realize the temperature change from room temperature to 77K, set the temperature by the temperature controller, scan the Raman spectrum at each required test temperature.

[0093] In the sample chamber of Example 1, PC10 sample is dropped between two parallel optical windows, the two optical windows are pressed by the sealing ring, the upper optical window and the sample chamber cover are pressed and sealed by 1 layer of sealing ring. Then, the two optical windows and the sealing ring are placed in the bottom support, the sample chamber cover of Example 1 is fixed by screwing the sample chamber cover on the top of the sample chamber. The entire sample chamber of Example 1 is fixed on the cryostat by the threads at the bottom. The inside of the cryostat is pumped to a vacuum of 10 -5 Pa order of magnitude by the mechanical pump and molecular pump unit, and the temperature point during cooling is controlled by the temperature controller. Finally, the light spot is focused on the sample surface by the microscopic confocal system, and the Raman spectrum is scanned by the iHR550 grating spectrometer.

[0094] Figure 4 (a) shows the Raman spectrum data of PC10 at room temperature obtained by the sample chamber of Example 1; Figure 4 (b) shows the Raman spectrum data of PC10 at room temperature for reference; Figure 4 (c) shows the low temperature Raman spectrum data of PC10. As Figure 4 shown, the Raman spectrum data of PC10 at room temperature, the main Raman peak position of PC10 is near 700cm -1 , the main Raman peak positions and intensities of the two correspond well; at low temperature, the main Raman peak positions correspond well with the reference data, only the Raman peaks near 400cm -1 and 1800cm -1 change. Since the phase transition point of this sample is near 173K, below 173K, the enhancement of part of the Raman peaks and the movement of the Raman peak near 1800cm -1 may be due to the phase change of the sample during temperature change. The above results prove that this sample chamber is suitable for room temperature and low temperature liquid Raman spectrum test.

[0095] Therefore, the sample chamber of the present application has good correspondence of the main Raman peak position with the reference data at room temperature and low temperature vacuum, high Raman peak intensity and high signal resolution.

[0096] Test Example 2

[0097] This test example is used to illustrate the implementation and effect of the sample cell of the present application for liquid vacuum Raman spectroscopy test at room temperature and low temperature.

[0098] This test example uses the sample cell of Example 2 to perform vacuum liquid Raman spectroscopy test at room temperature and low temperature for the liquid sample to be tested, ethanol and propylene carbonate + LiFSI (PC10 for short).

[0099] The low-temperature liquid vacuum Raman spectroscopy test method comprises the following steps:

[0100] 1) Place the sample to be tested in the sample cell, and then place the sample cell on the low-temperature thermostat;

[0101] 2) When testing at low temperature, the inside of the low-temperature thermostat is vacuumed and cooled; when testing the liquid sample to be tested, ethanol, at room temperature, vacuuming is required without cooling; when testing the liquid sample to be tested, propylene carbonate + LiFSI (PC10 for short), no vacuuming and cooling are required;

[0102] 3) Test the liquid vacuum Raman spectroscopy data, focus the light spot on the sample surface through the microscopic confocal system (10x and 50x objective lenses), excite through 532nm light, and collect the Raman spectroscopy data using the iHR550 grating spectrometer. Before cooling, the sample environment is vacuumed using a mechanical pump and a molecular pump, then the liquid nitrogen tank is connected to the low-temperature thermostat through the infusion rod to achieve temperature change from room temperature to 77K, the temperature is set through the temperature controller, and the Raman spectroscopy is scanned at each required test temperature.

[0103] PC10 samples and ethanol samples are respectively dropped into the sample cell of different sample cells, the bottom support, the sample cell optical window and the sample cell cover are extruded and sealed through 2 layers of sealing rings. The sample cell cover is fixed on the top of the sample cell using screws. The entire sample cell is fixed on the low-temperature thermostat through the bottom screw. The inside of the low-temperature thermostat is vacuumed to the order of 10 -5 Pa through the mechanical pump and molecular pump unit, then the liquid nitrogen tank is connected to the low-temperature thermostat using the infusion tube. The temperature controller is used to control the temperature point during the cooling process. Finally, the light spot is focused on the sample surface using the microscopic confocal system, and the Raman spectroscopy is scanned using the iHR550 grating spectrometer.

[0104] Figure 3 The experimental device for low-temperature liquid vacuum Raman test is shown; wherein: Figure 3 (a) shows the liquid sample cell in a vacuum state; Figure 3 (b), (c) and (d) show the overall diagram of the experimental device for low-temperature liquid Raman spectroscopy test. Figure 5 The Raman spectroscopy data of PC10 are shown; wherein: Figure 5(a) shows the Raman spectral data of PC10 from room temperature to 77K using the device of Example 2, the vacuum degree is 10 -5 Pa; Figure 5 (b) shows the Raman spectral data of PC10 at room temperature for reference. Figure 6 shows the Raman spectral data of ethanol; wherein: Figure 6 (a) shows the Raman spectral data of ethanol at room temperature for reference; Figure 6 (b) shows the Raman spectral data of ethanol at room temperature, room temperature vacuum, 77K vacuum obtained by the sample chamber of Example 2.

[0105] As Figure 5 shown, the Raman spectral data of PC10 at room temperature and low temperature, the main Raman peak position and intensity of both correspond well, proving that this sample chamber is suitable for room temperature and low temperature liquid Raman spectral test. As Figure 6 shown, the Raman spectral data of ethanol at room temperature, room temperature vacuum and 77K vacuum, its main Raman peak position and intensity correspond well with the reference data, and it is suitable for volatile samples to perform low temperature liquid Raman spectral test. The peak at 3000-4000 cm -1 of the reference data is a very wide OH peak, which is the only response peak of water. In the experiment, the response peak of water is also obtained, but since the purpose is to detect the Raman spectrum of ethanol, the existing Raman peak is sufficient to prove the accuracy of the experiment, so here the data obtained after treating the response peak of water as background is provided.

[0106] Therefore, the sample chamber of the present application, in the three environments of room temperature, vacuum and 77K vacuum, the main Raman peak position corresponds well with the reference data, the Raman peak intensity is high, and the signal resolution is high.

[0107] Test Example 3 (Control Test)

[0108] This test example is used to illustrate the comparison between the sample chamber for liquid vacuum Raman spectral test of the present application and the prior art.

[0109] From Table 1, compared with the prior art, the sample chamber of the present application not only realizes the liquid Raman spectral test at room temperature and liquid nitrogen temperature, the minimum temperature reaches 77K, but also realizes the low temperature liquid Raman test of liquid samples of wine, acid and other samples with strong volatility, easy to adsorb air and unstable corrosion, ensures that the sample is in a vacuum environment during the cooling process, the vacuum degree reaches 10 -5 Pa, in addition, it also realizes the room temperature and low temperature liquid Raman spectral test of weak signal samples.

[0110] Table 1 Comparison between the sample chamber for liquid vacuum Raman spectral test of Examples 1-2 and the prior art

[0111]

[0112] Although the above shows the effect of part of the embodiments, those skilled in the art should understand that according to the concept of the present application, the foregoing other embodiments which do not specifically show the effect or other technical solutions of the present application which are not shown in the embodiments can also achieve the following technical effects declared in the part of the invention content as compared with the embodiments:

[0113] 1. The liquid Raman spectrum test of room temperature and liquid nitrogen temperature is realized, and the lowest temperature reaches 77K.

[0114] 2. The liquid Raman test of room temperature and low temperature of liquid samples with strong volatility and easy adsorption of air is realized, and the sample is ensured to be in a vacuum environment in the cooling process, and the vacuum degree reaches 10 -5 Pa.

[0115] 3. The liquid Raman spectrum test of room temperature and low temperature of weak signal samples is realized.

[0116] 4. The Raman spectrum test of unstable and corrosive samples such as wine and acid is realized.

[0117] Although the present application has been described to a certain extent, obviously, appropriate changes can be made to each condition without departing from the spirit and scope of the present application. It can be understood that the present application is not limited to the described embodiments, but is subject to the scope of the claims, which includes equivalent replacement of each factor described.

Claims

1. A sample cell for liquid vacuum Raman spectroscopic testing, characterized in that, The sample chamber comprises a metal cover, an optical window, a sealing ring and a metal base; wherein: The inside of the sample chamber is extruded and sealed by the sealing ring, and the optical window and the sealing ring are located in the space composed of the metal cover and the metal base.

2. The sample chamber according to claim 1, wherein, The optical window is two mutually parallel optical windows; The two mutually parallel optical windows are provided with a sealing ring therebetween; and / or The two mutually parallel optical windows are each provided with a sealing ring above and below.

3. The sample chamber according to claim 1, wherein: The sample chamber further comprises a sample cell arranged below the optical window; and / or The sealing ring is a mutually parallel sealing ring arranged above and below the sample cell respectively; Preferably, the material of the sample cell is quartz glass, most preferably silica quartz glass.

4. The sample chamber according to any one of claims 1 to 3, wherein: The metal cover and the metal base are each provided with a hole; The optical window has a transmittance of > 95%, preferably > 97%, more preferably > 99%; and / or When the sample chamber is used for vacuum Raman spectrum testing of low-temperature liquid, the metal cover, the optical window, the sealing ring and the metal base are all made of low-temperature resistant material; Preferably, the minimum tolerance temperature of the low-temperature resistant material is ≥ 55K, more preferably ≥ 70K, most preferably ≥ 77K; and / or Preferably, the vacuum has a vacuum degree of 10 -6 Pa ~ 10 -4 Pa, more preferably 10 -6 Pa ~ 10 -5 Pa, most preferably 10 - 5 Pa.

5. The sample chamber according to any one of claims 1 to 4, wherein: The number of sealing rings is 2-5, preferably 2-4, more preferably 2-3; The material of the metal cover is copper, most preferably red copper; The material of the metal base is copper, most preferably red copper; The material of the optical window is quartz glass, most preferably silica quartz glass; and / or The material of the sealing ring is rubber or fluorine rubber.

6. The sample chamber according to any one of claims 1 to 5, wherein, The metal cover and the metal base are connected by a connecting component; and / or The bottom of the metal base also has a threaded structure; Preferably, the connecting component is a screw; More preferably, The number of screws is 3-6, preferably 4-5, most preferably 4; and / or The material of the screw is copper, most preferably red copper.

7. Use of the sample chamber according to any one of claims 1 to 6 in the preparation of a device for vacuum Raman spectrum testing of low-temperature liquid, room-temperature liquid, heated liquid and / or variable-temperature liquid.

8. A cryogenic liquid vacuum Raman testing apparatus, characterized by, The low-temperature liquid vacuum Raman testing device comprises the sample chamber according to any one of claims 1 to 6 and a low-temperature thermostat for maintaining a low-temperature testing environment; Preferably, the sample chamber is fixed on the low-temperature thermostat; More preferably, the sample chamber is fixed on the low-temperature thermostat through the threaded structure of the bottom of the metal base.

9. A method of testing a cryogenic liquid by vacuum Raman spectroscopy, characterized in that, The testing method comprises using the low-temperature liquid vacuum Raman testing device according to claim 8; Preferably, the testing method comprises the following steps: 1) placing the sample to be tested in the sample chamber, and placing the sample chamber on the cryostat; 2) vacuumizing and cooling the inside of the cryostat; 3) testing the low-temperature liquid vacuum Raman spectrum data; More preferably, the temperature of the cooling is ≥ 55 K, preferably ≥ 70 K, and most preferably ≥ 77 K; and / or The vacuum has a vacuum degree of 10 -6 Pa ~ 10 -4 Pa, preferably 10 -6 Pa ~ 10 -5 Pa, most preferably 10 -5 Pa.

10. The testing method according to claim 9, characterized in that: in step (1), the metal base, the optical window and the metal cover are extruded and sealed by a sealing ring, and the metal cover is fixed; and / or in step (3), the light spot is focused on the surface of the sample for scanning of the Raman spectrum.

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