Sample Fixing Tool and Testing Method for Attenuated Total Reflection Infrared Spectroscopy

Abstract

The present invention belongs to the field of asphalt tests, and particularly relates to a sample fixing tool for attenuated total reflection infrared spectroscopy testing and a testing method. The present invention monitors the pressure distribution at various positions of the sample contact surface through a pressure distribution monitoring module, and can directly feedback whether the sample contact surface is completely in contact with the sample below; on the premise that the sample contact surface is completely in contact with the sample, the final test pressure value is limited by observing the change in the peak height of the absorption peak at the same position in the infrared spectrogram of the sample, thereby ensuring close contact between the ATR crystal and the sample. Since the compression properties of different powder samples are different, by setting the final test pressure values of different powder samples, data support can be provided for the detection of subsequent same samples, improving the detection efficiency and the consistency of detection results, and thus realizing quantitative analysis.

Description

Technical Field

[0001] The present invention belongs to the field of asphalt tests, and particularly relates to a sample fixing tool for attenuated total reflection infrared spectroscopy testing and a testing method. Background Art

[0002] The mid-infrared spectral region is the fundamental absorption band of the vast majority of organic compounds and inorganic ions. Different molecular vibrations and transitions produce different spectra, manifested as different peak positions, and the intensity of the peaks varies according to the content of molecules or functional groups. According to the Lambert-Beer law, the absorbance is proportional to the concentration of the substance and the thickness of the absorption layer, making infrared spectroscopy one of the effective means for analyzing the chemical structure of substances and quantitative detection. As a method for characterizing the composition and structure of materials, infrared spectroscopy is widely used in the fields of chemical synthesis and polymer materials. In recent years, the application of infrared spectroscopy in the transportation field has also been increasing, and it has currently been successfully applied to the determination of the modifier content in SBS modified asphalt, the oil source tracing of petroleum asphalt, etc.

[0003] Infrared spectroscopy testing can be divided into transmission and attenuated total reflection according to the optical path. Compared with the conventional transmission infrared spectroscopy technology, in attenuated total reflection infrared spectroscopy technology, the infrared light emitted from the light source passes through a crystal with a large refractive index and then projects onto the surface of a sample with a small refractive index. When the incident angle is greater than the critical angle, total reflection of the incident light will occur. In fact, not all of the infrared light is reflected back, but it penetrates to a certain depth inside the sample surface and then returns to the surface. During this process, the sample selectively absorbs in the incident light frequency region, the intensity of the reflected light weakens, and a graph similar to the transmission absorption is generated, thereby obtaining the structural information of the chemical components on the surface layer of the sample. In the prior art, the principle of light transmission is utilized. A liquid cell is used to test liquid samples, and the pressing tablet method is used to test light-colored and easily ground samples. However, for some substances with hard texture, difficult to grind, dark color, or difficult to dissolve in organic solvents, the total reflection infrared spectroscopy technology is usually used for testing.

[0004] When using the attenuated total reflection infrared spectroscopy technology to test materials with a dark color and low solubility in organic solvents such as coal-based super-hard asphalt and rock asphalt, or other samples that require the use of an ATR accessory, the material to be detected needs to be made into powder and placed above the test crystal. The sample is brought into close contact with the test crystal by pressing down the ATR pressing rod for testing. The existing ATR test crystal is set in the middle of the test platform and is on the same plane as the test platform. When the powder sample is set above the ATR test crystal, a conical small bulge is usually formed. However, the existing ATR accessories such as Figure 1As shown, the lower end of the ATR pressure bar 100 is a rigid cylindrical indenter 101, and the ATR pressure bar 100 can only be mechanically pressed down. It is impossible to detect whether the entire lower surface of the cylindrical indenter 101 is in contact with the sample, and it is also impossible to detect whether the powder sample is in close contact with the test crystal 201. This will result in a weak infrared spectrum signal, and some absorption peaks with relatively small absorbance cannot be displayed, thus seriously affecting the accuracy of the test results. At this time, the qualitative analysis error is relatively large, and quantitative analysis cannot be carried out at all.

[0005] Chinese patent document CN214174154U discloses an infrared spectrometer for rapidly detecting organic compounds, which includes a machine body and a measurement module detachably installed on the machine body. The measurement module includes a crystal disk arranged on the upper end surface and an indenter assembly installed at a relative position of the crystal disk; the indenter assembly includes a lifting mechanism installed on the measurement module, a transfer sleeve and a pressure seat arranged at the upper end of the lifting mechanism, and a probe mechanism installed on one side of the transfer sleeve. This device controls the descent of the probe mechanism through the lifting mechanism to make the pressure head contact the sample. The upper end of the transfer sleeve is inserted into the pressure seat. When the pressure head abuts against the sample, the pressure cylinder transfers the pressure to the elastic plate through the spring and is detected by the pressure sensor. After the lifting mechanism continues to descend to an appropriate pressure, it is transmitted to the controller in the machine body through the pressure sensor, and the controller controls the drive motor to stop the descent of the lifting mechanism, realizing the close contact between the ATR crystal and the sample, making the experimental data more accurate, convenient to use, and suitable for popularization. The above patent document is provided with a pressure sensor for monitoring the pressure value between the pressure head and the sample to judge whether the ATR crystal is in close contact with the sample. It is only applicable to hard materials with parallel upper and lower surfaces of the sample. For powder or granular materials, since the pressure head is rigid and the powder or granular materials have a certain compression ratio, when they are pressed to a certain extent, they cannot be further compacted. When the thickness distribution of the powder or granular materials under the pressure head is uneven, it is impossible to ensure that the entire lower surface of the pressure head is in contact with the powder or granular materials, and there is a risk that some powder or granular material samples cannot be compacted and thus cannot be in close contact with the ATR crystal. Therefore, the actual contact situation between the ATR crystal and the sample cannot be accurately determined only by the pressure value, and the above patent does not point out how to determine that the sample can be in close contact with the detection crystal under a certain pressure, so the stability of the test results cannot be guaranteed. Summary of the Invention

[0006] The object of the present invention is to provide a sample fixing tool and a testing method for attenuated total reflection infrared spectroscopy. The present invention uses a pressure distribution monitoring module to monitor the pressure distribution at various positions of the sample contact surface to determine whether the sample contact surface is in full contact with the sample, which is more intuitive and can quantitatively analyze the tightness of the contact between the sample and the ATR crystal. In addition, in the testing method, on the premise that the sample contact surface is in full contact with the sample, the final test pressure value is limited by observing the change in the peak height of the absorption peak at the same position in the infrared spectrum of the sample, so as to ensure the tight contact between the ATR crystal and the sample, and improve the consistency and accuracy of the test results.

[0007] To achieve the above object, the present invention provides the following technical solution: A sample fixing tool for attenuated total reflection infrared spectroscopy, comprising a press head attachment and a pressure distribution monitoring module. The press head attachment is provided with a sample contact surface, and the pressure distribution monitoring module is arranged on the sample contact surface;

[0008] The pressure distribution monitoring module is used to monitor the pressure distribution at various positions of the sample contact surface to determine whether the sample contact surface is in full contact with the sample. Specifically, when the pressure at each position of the sample contact surface is greater than zero, it indicates that the sample contact surface is in full contact with the sample. When there is still a part with zero pressure on the sample contact surface when the maximum pressure value at each position on the sample contact surface reaches the set pressure value, it is necessary to adjust the shape of the sample or the sample contact surface so that the sample contact surface is in full contact with the sample. By monitoring the pressure values, that is, the pressure distribution, received at various positions of the sample contact surface, the minimum pressure value received on the sample contact surface indirectly reflects the tightness of the contact between the sample and the ATR crystal.

[0009] The technical solution of the present invention also includes: The press head attachment is made of an elastic material. The press head attachment is provided with a conical sample chamber, and the sample contact surface is the inner surface of the sample chamber. The conical sample chamber can be adapted to the conical sample bulge, ensuring that the press head attachment is in contact with the sample to the greatest extent. If a flat press head attachment is used, the edge of the press head attachment will not be in contact with the edge of the sample bulge. As the ATR pressure rod is pressed down, the inner surface of the conical sample chamber gradually compresses and deforms from the periphery to the center to contact the sample below. Since the press head attachment is made of an elastic material, and the elastic material is also called an elastomeric material, the elastomeric material can quickly return to its approximate initial shape and size after being deformed under force and then the external force is removed. Therefore, it is used as the manufacturing material of the press head attachment in the present invention, which can realize reversible deformation under force and ensure that the sample contact surface at each position is in contact with the sample of different thicknesses below.

[0010] The technical solution of the present invention also includes: It further includes a vacuum pump. The press head attachment includes a sealing sleeve and a vacuum bag film arranged inside the sealing sleeve. The sealing sleeve and the vacuum bag film form a sealed cavity. A sealing strip is arranged on the lower end surface of the sealing sleeve, and the vacuum pump is communicated with the sealed cavity;

[0011] The sample contact surface is the lower surface of the vacuum bag film. Since the vacuum bag film is a flexible material, based on the principle of vacuum forming, by evacuating the air, the vacuum bag film can be closely contacted with the sample, and the sample can be compacted by using the pressure difference.

[0012] The technical solution of the present invention further includes a sample shape adjustment mechanism. The sample shape adjustment mechanism includes a limit sleeve sleeved outside the indenter accessory and a vibrator fixedly arranged on the outer wall of the limit sleeve. The indenter accessory can slide up and down along the axial direction of the limit sleeve, and the vibrators are symmetrically arranged relative to the center line of the limit sleeve; the vibrator can make the limit sleeve generate vibrations in the horizontal direction;

[0013] The sample contact surface is the lower end surface of the indenter accessory. Since the limit sleeve is a hollow structure, the vibrator can drive the limit sleeve to vibrate, and the vibration wave generated by the limit sleeve can make the powder on the test table vibrate, so that the sample is evenly distributed in the limit sleeve, making the upper surface of the sample smoother, so that the sample contact surface is in full contact with the sample.

[0014] The technical solution of the present invention further includes: the pressure distribution monitoring module includes an array of pressure sensors.

[0015] The technical solution of the present invention further includes: the array of pressure sensors includes thin-film pressure sensors. The thickness of the thin-film pressure sensor is as low as a few hundred nanometers to dozens of micrometers, and a film can be directly formed on the surface of the measured part without affecting the internal environment of the device. It is suitable for various complex surfaces. Because it is a flexible material, it can be bent and folded, and is suitable for detecting position information, pressure distribution information, and pressure magnitude information. In the present invention, the thin-film pressure sensor can deform together with the sample contact surface of the indenter accessory, so as to measure the pressure distribution and pressure magnitude on the sample contact surface, so as to judge whether the sample contact surface is in full contact with the powder sample below.

[0016] The present invention also discloses a method for performing attenuated total reflection infrared spectroscopy test by using the above sample fixing tool, including the following steps:

[0017] S1. Turn on the Fourier transform infrared spectrometer, load the ATR accessory, install the sample fixing tool under the ATR pressure bar, and set the test parameters of the Fourier transform infrared spectrometer;

[0018] S2. First perform a background test, and then place a quantitative test sample in the test window, and the sample amount should completely cover the test crystal in the test window;

[0019] S3. Press down the ATR lever to make the sample fixing tool contact the test tabletop, apply force to the sample contact surface until the minimum pressure indication detected by the pressure distribution monitoring module is greater than zero, record the minimum pressure indication P measured by the pressure distribution monitoring module, and test the sample to obtain the infrared spectrogram of the sample.

[0020] S4. Adjust the force applied to the sample contact surface multiple times, test the sample, and observe the infrared spectrogram of the sample. When the peak height of the absorption peak at the same position in the infrared spectrogram no longer increases or meets the requirements of the tester, the minimum pressure indication P' measured by the pressure distribution monitoring module at this time is used as the final pressure value for subsequent tests of the same type of sample.

[0021] Another technical solution of the present invention is: in step S3, when the maximum pressure at each part of the sample contact surface measured by the pressure distribution monitoring module reaches the set pressure value P 0 and there is still a part with zero pressure on the sample contact surface, adjust the shape of the sample or the sample contact surface so that the sample contact surface is in full contact with the sample.

[0022] Another technical solution of the present invention is: after turning on the Fourier transform infrared spectrometer in step S1, wait for the light source to stabilize for 20 - 30 minutes before testing.

[0023] Compared with the prior art, the beneficial effects of the present invention are: by monitoring the pressure distribution at each part of the sample contact surface through the pressure distribution monitoring module, the present invention can directly feedback whether the sample contact surface is in full contact with the sample below.

[0024] And to determine whether the compactness of the powder sample meets the test requirements, on the premise that the sample contact surface is in full contact with the sample, the final test pressure value is limited by observing the change in the peak height of the absorption peak at the same position in the infrared spectrogram of the sample, thereby ensuring close contact between the ATR crystal and the sample. Since the compression properties of different powder samples are different, by testing the final test pressure values of different samples, data support can be provided for the detection of subsequent same samples, improving the detection efficiency and the consistency of detection results, and thus realizing quantitative analysis.

[0025] Invention concept: During the actual testing process, the powder or particle sample is directly laid on the ATR crystal and is guaranteed to completely cover the ATR crystal. The ATR pressure rod is used to press down to make the powder or particle sample fit tightly with the ATR crystal. However, during the actual operation, the laying of the powder or particle sample cannot ensure uniform thickness everywhere. Affected by gravity, the sample is generally conical, that is, the thickness is thick in the middle and thin around. The existing ATR pressure head is a rigid part with a flat lower surface. At the same time, the powder or particle sample has a certain compression ratio. When the ATR pressure head is pressed down to a certain distance, it can no longer move downward, resulting in the thin powder or particle sample being unable to contact with the lower surface of the ATR pressure head, that is, it cannot ensure that all powder or particle samples are in close contact with the ATR crystal, resulting in inaccurate test results and poor consistency in the test results of the same samples.

[0026] The present invention uses a pressure distribution monitoring module to monitor the pressure distribution at various locations on the sample contact surface to determine whether the sample contact surface is completely in contact with the sample. This is more intuitive and can quantitatively analyze the degree of contact between the sample and the ATR crystal, which is used to ensure and improve the consistency of the test results of the same sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of an existing attenuated total reflection infrared spectrometer;

[0028] Figure 2 A stereoscopic diagram of a sample fixing tool for attenuated total reflection infrared spectroscopy testing according to the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of a sample fixing tool for attenuated total reflection infrared spectroscopy testing according to Example 1 of the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of a sample fixing tool for attenuated total reflection infrared spectroscopy testing according to Example 2 of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of a sample fixing tool for attenuated total reflection infrared spectroscopy testing according to Example 3 of the present invention;

[0032] Figure 6 The infrared spectrum of the sample tested by the attenuated total reflection infrared spectrum testing method of Example 1 of the present invention;

[0033] In the figure, 100 ATR pressure rod, 101 cylindrical pressure head, 200 test table, 201 test crystal, 300 rotating bracket;

[0034] 1. Pressure head accessories, 2. Sample contact surface, 3. Sample chamber, 4. Vacuum pump;

[0035] 11 sealing sleeve, 12 vacuum bag film, 13 sealing chamber;

[0036] 5 Limiting sleeve, 6 Vibrator, 7 Elastic buffer Specific implementation mode

[0037] The present invention will be described in detail below with reference to the accompanying drawings:

[0038] Embodiment 1

[0039] As Figure 2 shown, a sample fixing tool for attenuated total reflection infrared spectroscopy test includes a pressing head attachment 1 and a pressure distribution monitoring module. The pressing head attachment 1 is provided with a sample contact surface 2, and the pressure distribution monitoring module is arranged on the sample contact surface 2. The pressure distribution monitoring module is an array pressure sensor, and the array pressure sensor includes a thin film pressure sensor.

[0040] The pressure distribution monitoring module is used to monitor the pressure distribution at each part of the sample contact surface 2 to judge whether the sample contact surface 2 is in full contact with the sample.

[0041] As Figure 3 shown, the pressing head attachment 1 is made of an elastic material, specifically a rubber material. The pressing head attachment 1 is provided with a conical sample chamber 3, and the sample contact surface 2 is the inner surface of the sample chamber 3.

[0042] A method for performing an attenuated total reflection infrared spectroscopy test using the above sample fixing tool for attenuated total reflection infrared spectroscopy test specifically includes the following steps:

[0043] In this embodiment, the fixing tool and test method provided by the present invention are used for the infrared spectroscopy test of coal-based super hard asphalt.

[0044] S1. Preparation work before the test: Turn on the Fourier transform infrared spectrometer and power it on for 20 min. After the light source is stable, load the ATR attachment. Specifically, install the ATR pressing rod 100 on the rotating bracket 300. As Figure 3 shown, install the sample fixing tool under the ATR pressing rod 100. The specific assembly method is that the pressing head attachment 1 is directly sleeved under the ATR pressing rod 100 by setting a fixing hole at the upper end that matches the lower end of the ATR pressing rod 100. Thoroughly clean the tool and the diamond crystal in the middle of the ATR test window with alcohol. After the solvent has completely evaporated, connect it to the ATR attachment and set the number of scans, sample information, test result storage location, etc.

[0045] S2. First, perform a background test, and then place 1 mg of coal-based super hard asphalt powder, which is the sample to be tested, in the test window. The sample amount completely covers the test crystal 201 in the test window, and the sample amount is measured by the sample weight.

[0046] S3. Rotate the rotary bracket 300 to move the indenter attachment 1 above the sample exactly. Press down the ATR pressing rod 100 to apply force to the indenter attachment 1 until the minimum pressure indication value of the pressure distribution monitoring module is greater than zero. Record the minimum pressure indication value P1 measured by the pressure distribution monitoring module, and test the sample to obtain the infrared spectrum of the sample.

[0047] When using the sample fixing tool provided in this embodiment, since the indenter attachment 1 is made of an elastic material and the indenter attachment 1 is provided with a conical sample chamber 3, during the process of pressing down the ATR pressing rod 100, the sample chamber 3 will be flattened and deformed, so that the inner surface of the sample chamber 3, that is, the sample contact surface 2, gradually fits the sample below, so that the sample contact surface 2 is in full contact with the sample, and the elastic material can generate elastic force to compress the sample, so that the sample is in close contact with the test crystal 201.

[0048] S4. Adjust the distance between the ATR pressing rod 100 and the test table 200 downward in three steps, repeat testing the sample, and record the minimum pressure indication values measured by the corresponding pressure distribution monitoring module as P2, P3, and P4 respectively. Observe the infrared spectrum of the sample and find that when the pressure is P3 and P4, the peak height of the absorption peak at the same position in the infrared spectrum remains unchanged, and at the same time, the corresponding infrared spectrum can also clearly reflect the structural information of the coal-based super hard asphalt.

[0049] Then, during the subsequent testing process of the coal-based super hard asphalt, control and adjust the contact condition corresponding to the minimum pressure indication value measured by the pressure distribution monitoring module reaching P3 as the unified test condition. As Figure 6 shown, a better infrared spectrum is obtained.

[0050] Embodiment 2

[0051] The difference from Embodiment 1 is that, as Figure 4 shown, the sample fixing tool further includes a vacuum pump 4. The indenter attachment 1 includes a sealing sleeve 11 and a vacuum bag film 12 arranged inside the sealing sleeve 11. The sealing sleeve 11 and the vacuum bag film 12 form a sealed cavity 13. The lower end surface of the sealing sleeve 11 is provided with a sealing strip, and the vacuum pump 4 communicates with the sealed cavity 13.

[0052] The sample contact surface 2 is the lower surface of the vacuum bag film 12.

[0053] When performing infrared spectroscopy tests on coal-based ultra-hard pitch using the sample fixing tool of this embodiment, the sealing sleeve 11 is fixedly arranged below the ATR pressure bar 100. Press down the ATR pressure bar 100 until the sealing strip on the lower end surface of the sealing sleeve 11 contacts the test table 200. Start the vacuum pump 4 to evacuate the sealing cavity 13, so that the vacuum bag film 12 deforms and closely adheres to the sample in the sealing cavity 13, making the sample contact surface 2 in full contact with the sample, and using atmospheric pressure to compress the sample, so that the sample is in close contact with the test crystal 201.

[0054] Example 3

[0055] The difference from Example 1 is that, as Figure 5 shown, the sample fixing tool further includes a sample morphology adjustment mechanism. The sample morphology adjustment mechanism includes a limit sleeve 5 sleeved outside the indenter attachment 1 and a vibrator 6 fixedly arranged on the outer wall of the limit sleeve 5. The limit sleeve 5 can slide up and down along the axial direction of the indenter attachment 1. The vibrators 6 are symmetrically arranged relative to the center line of the limit sleeve 5 to produce a better vibration effect.

[0056] The sample contact surface 2 is the lower end surface of the indenter attachment 1.

[0057] When performing infrared spectroscopy tests on coal-based ultra-hard pitch using the sample fixing tool of this embodiment, the indenter attachment 1 is fixedly arranged at the lower end of the ATR pressure bar 100. The limit sleeve 5 is slidably sleeved on the ATR pressure bar 100. An elastic buffer 7 is arranged between the limit sleeve 5 and the ATR pressure bar 100. The elastic buffer 7 is fixedly arranged on the limit sleeve 5. The elastic buffer 7 is a rubber spring. By pressing down the ATR pressure bar 100 until the lower end surface of the limit sleeve 5 contacts the test table 200, the sample is located inside the limit sleeve 5 at this time.

[0058] During the downward pressing process of the indenter attachment 1, start the vibrator 6 at the same time. The vibrator 6 can make the powdery or granular sample in the limit sleeve 5 evenly distributed by vibrating the limit sleeve 5. As the indenter attachment 1 is further pressed down, the indenter attachment 1 moves downward relative to the limit sleeve 5, and the distance between the sample contact surface 2 and the sample gradually decreases. Then the range where the sample moves due to the vibration of the vibrator 6 becomes smaller and smaller. Blocked by the sample contact surface 2 and the limit sleeve 5, the upper surface of the sample will tend to be flat, and the upper surface of the sample will gradually fit the sample contact surface 2, so as to achieve full contact between the sample contact surface 2 and the sample.

[0059] Example 4

[0060] In this embodiment, infrared spectroscopy tests are performed on SBS modified asphalt with different modifier contents and coal-based ultra-hard pitch modified asphalt (SHA) using the fixing tool and test method provided by the present invention.

[0061] The sample fixing tool and the test method are the same as those in Example 1. The test results are shown in Table 1 as follows.

[0062] Table 1

[0063]

[0064] By analyzing the peak area of the characteristic absorption peak of the modifier in the infrared spectrogram, it is found that there is a good linear relationship between it and the modifier content, indicating that the attenuated total reflection infrared spectroscopy test method of the present invention has the advantage of high repeatability.

Claims

1. A sample fixing tool for attenuated total reflection infrared spectroscopy testing, characterized in that: It includes a pressing head accessory (1) and a pressure distribution monitoring module. The pressing head accessory (1) is provided with a sample contact surface (2), and the sample contact surface (2) can be deformed under pressure to fit the sample and make full contact with the sample. A pressure distribution monitoring module is arranged on the sample contact surface (2); The pressure distribution monitoring module includes an array of pressure sensors; The pressure distribution monitoring module is used to monitor the pressure distribution at various positions of the sample contact surface (2) to determine whether the sample contact surface (2) is in full contact with the sample; The pressing head accessory (1) is made of an elastic material. The pressing head accessory (1) is provided with a conical sample chamber (3), and the sample contact surface (2) is the inner surface of the sample chamber (3); The sample fixing tool for attenuated total reflection infrared spectroscopy testing further includes a vacuum pump (4). The pressing head accessory (1) includes a sealing sleeve (11) and a vacuum bag film (12) arranged inside the sealing sleeve (11). The sealing sleeve (11) and the vacuum bag film (12) form a sealed cavity (13). A sealing strip is arranged on the lower end surface of the sealing sleeve (11), and the vacuum pump (4) communicates with the sealed cavity (13); The sample contact surface (2) is the lower surface of the vacuum bag film (12).

2. The sample fixing tool for attenuated total reflection infrared spectroscopy testing according to claim 1, characterized in that: It further includes a sample shape adjusting mechanism. The sample shape adjusting mechanism includes a limiting sleeve (5) sleeved outside the pressing head accessory (1) and a vibrator (6) fixedly arranged on the outer wall of the limiting sleeve (5). The pressing head accessory (1) can slide up and down along the axis of the limiting sleeve (5); The sample contact surface (2) is the lower end surface of the pressing head accessory (1).

3. The sample fixing tool for attenuated total reflection infrared spectroscopy testing according to claim 1, characterized in that: The array of pressure sensors includes thin film pressure sensors.

4. A method for attenuated total reflection infrared spectroscopy testing using the sample fixing tool according to any one of claims 1-3, characterized in that, It includes the following steps: S1. Turn on the Fourier transform infrared spectrometer, load the ATR accessory, install the sample fixing tool under the ATR pressing rod (100), and set the test parameters of the Fourier transform infrared spectrometer; S2. First, perform a background test, and then place a quantitative test sample in the test window. The amount of the sample should completely cover the test crystal (201) in the test window; S3. Press down the ATR pressing rod (100) to apply force to the sample contact surface (2) until the minimum pressure indication value detected by the pressure distribution monitoring module is greater than zero. Record the minimum pressure indication value P measured by the pressure distribution monitoring module, test the sample, and obtain the infrared spectrum of the sample; S4. Adjust the applied force on the sample contact surface (2) multiple times, test the sample, and observe the infrared spectrum of the sample. When the peak height of the absorption peak at the same position in the infrared spectrum no longer increases or meets the requirements of the tester, then the minimum pressure indication value P' measured by the pressure distribution monitoring module at this time is used as the final pressure value for subsequent tests of the same type of sample.

5. The attenuated total reflection infrared spectroscopy test method according to claim 4, characterized in that: in step S3, when the maximum pressure at each part of the sample contact surface (2) measured by the pressure distribution monitoring module reaches the set pressure value P0 and there are still parts on the sample contact surface (2) where the pressure is zero, the shape of the sample or the sample contact surface (2) is adjusted so that the sample contact surface (2) is in full contact with the sample.

6. The attenuated total reflection infrared spectroscopy test method according to claim 4, characterized in that: after the Fourier transform infrared spectrometer is turned on in step S1, wait for the light source to stabilize for 20 - 30 minutes and then perform the test.

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