Simple attenuated total reflection accessory suitable for in-situ infrared spectrum characterization

Abstract

The invention relates to a simple attenuated total reflection accessory suitable for in-situ infrared spectrum characterization, which comprises a shell, a detachable light path top plate, a silicon crystal assembly and a reflector assembly, and is characterized in that the detachable light path top plate covers the shell, a closed space is formed by the detachable light path top plate and the shell, and the detachable light path top plate comprises a fixed plate; the silicon crystal assembly is arranged on the lower surface of the fixing plate, and a sample cavity for containing a catalyst sample is formed in the silicon crystal assembly; the reflector assembly comprises four reflectors which are arranged in sequence, infrared light introduced from the infrared light inlet is incident upwards to the surface of the silicon crystal assembly through the two reflectors, and the infrared light reflected by the surface of the silicon crystal forms a total reflection path through the two reflectors and is finally emitted out from the infrared light outlet. Compared with the prior art, the invention provides a novel attenuated total reflection accessory with high sensitivity, quick response capability and cross-domain compatibility.

Description

Technical Field

[0001] The invention relates to the technical field of instrument analysis, in particular to a simple attenuated total reflection accessory suitable for in-situ infrared spectrum characterization. Background Art

[0002] Attenuated total reflectance (ATR) technology has won wide recognition in the field of infrared spectroscopy analysis for its simple operation process and non-destructive testing characteristics. This technology allows users to place samples directly on the crystal for testing, eliminating the tedious sample preparation steps, which not only speeds up the experimental process but also reduces potential damage to the sample. By optimizing the interaction between the sample and infrared light, ATR technology significantly improves the detection sensitivity of the sample surface and near-surface area, making the analysis of opaque or strongly absorbing materials more feasible.

[0003] In addition, in addition to traditional qualitative analysis, ATR technology can also be extended to quantitative analysis through precise calibration methods, further expanding the breadth of its application. After the test, the sample can be completely recovered, which is especially important for precious or limited samples. The high compatibility of ATR technology also means that it can be easily used with most existing infrared spectrometers, enhancing the versatility of the instrument and playing a key role in many fields such as materials science, chemical analysis, and biomedicine.

[0004] However, the existing technology still has the following key problems:

[0005] Large energy loss in the optical path: The traditional optical path relies on a single or a few reflectors to achieve total reflection. The coating material has a low reflectivity and a high surface roughness, which leads to significant energy loss of infrared light during transmission. In particular, the detection sensitivity of weakly adsorbed species (such as low-concentration reaction intermediates) is insufficient, making it difficult to capture fast transient reaction signals.

[0006] For example, commercial ATR accessories (such as PIKE products) have good stability, but their optical path adopts a mechanical folding structure, with a large number of reflectors at fixed angles, resulting in a long optical path and significant energy loss. In particular, when detecting volatile liquids or gas samples, the signal strength is insufficient and the dynamic response is delayed. In addition, its sealing structure cannot meet the requirements of in-situ experiments at high temperatures (>200°C) or highly corrosive media, which seriously restricts its application in the study of complex systems.

[0007] Therefore, it is urgent to develop a new attenuated total reflection accessory with high sensitivity, rapid response capability and cross-domain compatibility to break through the existing technical bottleneck. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization, and to extract a new attenuated total reflection accessory with high sensitivity, rapid response capability and cross-domain compatibility.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] The present invention provides a simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization, comprising a housing, a detachable optical path top plate, a silicon crystal component, and a reflector component, wherein specifically:

[0011] The housing has an infrared light inlet and an infrared light outlet on its side;

[0012] A detachable optical path top plate is covered on the outer shell, the detachable optical path top plate and the outer shell form a closed space, and the detachable optical path top plate includes a fixing plate;

[0013] A silicon crystal assembly is disposed on the lower surface of the fixing plate, and a sample cavity for arranging a catalyst sample is disposed on the silicon crystal assembly;

[0014] The reflector assembly includes four reflectors arranged in sequence. The infrared light introduced from the infrared light entrance is incident upward to the surface of the silicon crystal assembly through two reflectors. The infrared light reflected by the silicon crystal surface forms a total reflection path through the two reflectors and is finally emitted from the infrared light exit.

[0015] Further, the reflector assembly includes a first reflector and a second reflector arranged on the light-incoming side of the housing, and also includes a third reflector and a fourth reflector arranged on the light-emitting side of the housing;

[0016] The first reflector, the second reflector, the third reflector and the fourth reflector are all made of gold-plated mirror surfaces, and the mirror surface roughness is ≤Ra 0.8μm.

[0017] Furthermore, the first reflector, the second reflector, the third reflector and the fourth reflector are all fixed in the housing via a fixing block with an inclined surface, and the fixing block is connected to the housing via a buckle or a bolt.

[0018] Further, the first reflector is inclined toward the infrared light entrance and reflects the infrared light to the second reflector.

[0019] Furthermore, the second reflector is used to direct the infrared light upward through the sample cavity and incident on the surface of the silicon crystal component.

[0020] Furthermore, the third reflector reflects the infrared light reflected by the silicon crystal to the fourth reflector.

[0021] Furthermore, the fourth reflector is used to reflect the infrared light to the infrared light outlet to form a total reflection light path.

[0022] Furthermore, a sealing ring is arranged on the lower surface of the detachable optical path top plate near the edge.

[0023] Furthermore, the outer shell is a shell structure with an opening at the top, a shelf is provided at the inner edge of the top opening of the outer shell, and the fixing plate cover is provided on the outer shell so that the sealing ring is in close contact with the shelf.

[0024] Furthermore, the silicon crystal assembly includes a silicon crystal body and a sample cavity, and the silicon crystal body is fixed to the lower surface of the fixing plate by fasteners.

[0025] Furthermore, the sample cavity is a groove of 2-3 mm and a quartz glass window that can cover the groove. The sample cavity is arranged on the lower surface of the silicon crystal body, and the quartz glass window is connected to the silicon crystal body by a buckle.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) The present invention significantly improves the energy utilization rate of infrared light and reduces the energy loss during optical transmission through optimized optical path design, so that the infrared signal has a faster response speed to dynamic changes in reaction conditions (such as rapid temperature fluctuations or sudden changes in concentration). It is particularly suitable for in-situ monitoring of transient reactions, and breaks through the problem of signal delay or low signal-to-noise ratio caused by insufficient energy in traditional optical paths.

[0028] 2) The present invention achieves functional replacement of conventional attenuated total reflection accessories through a modular optical path structure (such as a detachable reflector group and a silicon crystal component), while avoiding complex optical alignment and calibration steps, and is easy and efficient to operate; its compact housing design and sealing structure further reduce the experimental preparation time, and is suitable for routine laboratory and high-throughput testing scenarios.

[0029] 3) By flexibly replacing the in-situ reaction cell (such as a dedicated cell body adapted to thermochemical, electrochemical or photochemical reactions), the present invention can be expanded to the attenuated total reflection in-situ characterization in multidisciplinary fields, breaking through the limitations of traditional accessories on a single experimental type. Combined with the high light transmittance of silicon crystals and the closed sample chamber design, stable operation under different reaction conditions (such as highly corrosive media, high temperature and high pressure) is ensured, significantly improving the versatility and research value of the experimental device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of a simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization in the present invention;

[0031] Figure 2It is a schematic diagram of the arrangement structure of the reflector in the present invention;

[0032] Figure 3 It is a schematic diagram of the external structure of the simple attenuated total reflection accessory in the present invention;

[0033] Figure 4 Schematic diagram of the setup structure of the silicon crystal body.

[0034] Figure 5 It is the infrared spectrum obtained by testing ethanol in the PIKE optical path and the optical path accessory developed by the present invention.

[0035] In the attached drawings: 1. outer shell; 2. infrared light inlet; 3. infrared light outlet; 4. fixing plate; 5. first reflector; 6. second reflector; 7. third reflector; 8. fourth reflector; 9. sealing ring; 11. shelf; 12. silicon crystal body. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0037] Example 1

[0038] The simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization in this embodiment includes a housing 1, a detachable optical path top plate, a silicon crystal component, and a reflector component, wherein the specific Figures 1 to 4 .

[0039] The side of the housing 1 is provided with an infrared light inlet 2 and an infrared light outlet 3. A removable optical path top plate is covered on the housing 1, and the removable optical path top plate and the housing form a closed space, and the removable optical path top plate includes a fixing plate 4. A sealing ring 8 is provided near the edge of the lower surface of the removable optical path top plate. The housing 1 is a shell structure with an opening at the top, and a shelf 11 is provided at the inner edge of the top opening of the housing 1. The fixing plate 4 is covered on the housing 1, and the sealing ring 8 is closely abutted against the shelf 11.

[0040] The silicon crystal assembly is arranged on the lower surface of the fixing plate 4, and a sample cavity for installing the catalyst sample is arranged on the silicon crystal assembly. The silicon crystal assembly includes a silicon crystal body 12 and a sample cavity, and the silicon crystal body 12 is fixed to the lower surface of the fixing plate 4 by fasteners. The sample cavity is a 2-3 mm groove and a quartz glass window that can be covered on the groove. The sample cavity is arranged on the lower surface of the silicon crystal body 12, and the quartz glass window is connected to the silicon crystal body 12 by a buckle.

[0041] The reflector assembly includes four reflectors arranged in sequence. The infrared light introduced from the infrared light inlet 2 is incident upward to the surface of the silicon crystal assembly through two reflectors. The infrared light reflected by the silicon crystal surface forms a total reflection path through the two reflectors and is finally emitted from the infrared light outlet 3.

[0042] The reflector assembly includes a first reflector 5 and a second reflector 6 arranged on the light inlet side of the housing 1, and also includes a third reflector 6 and a fourth reflector 7 arranged on the light outlet side of the housing 1; the first reflector 5, the second reflector 6, the third reflector 6, and the fourth reflector 7 are all made of gold-plated mirrors, and the mirror roughness is ≤Ra0.8μm. The first reflector 5 is tilted toward the infrared light inlet 2 and reflects the infrared light to the second reflector 6. The second reflector 6 is used to pass the infrared light upward through the sample cavity and incident on the surface of the silicon crystal assembly. The third reflector 7 reflects the infrared light reflected by the silicon crystal to the fourth reflector 8. The fourth reflector 7 is used to reflect the infrared light to the infrared light outlet 3 to form a total reflection light path.

[0043] In a specific implementation, the first reflector 5 , the second reflector 6 , the third reflector 7 , and the fourth reflector 7 are all fixed in the housing 1 via a fixing block with an inclined surface, and the fixing block is connected to the housing 1 via a buckle or bolts.

[0044] During the specific implementation process, the housing 1 of the present invention adopts a shell structure with an opening at the top, and a shelf 11 is provided on the inner edge of the top opening. The removable optical path top plate is provided on the housing through a threaded connection cover, and is tightly abutted against the shelf 11 with the help of a sealing ring 8 on the edge to form a closed optical cavity. This modular design allows for rapid replacement of optical path components (such as reflectors or silicon crystal components), while the sealing structure effectively isolates external environmental interference (such as gas leakage or temperature and humidity changes) to ensure the stability of infrared light transmission. In addition, the infrared light information acquisition board can be directly integrated on the fixed plate 4 of the present invention, and can be directly connected to a spectrometer for real-time data acquisition, thereby simplifying the experimental process.

[0045] In the specific implementation process, the silicon crystal assembly is fixed to the lower surface of the fixed plate 4 by fasteners, and the grooved sample cavity (depth 2-3mm) on the lower surface provides a stable loading platform for the catalyst sample. The top of the sample cavity is covered with a quartz glass window 13, and an airtight seal is achieved by a clamping ring 14, which is compatible with the in-situ characterization of solid, liquid and gas samples. As a highly light-transmitting medium, the surface of the silicon crystal is precisely polished, which can efficiently reflect the incident infrared light to the reaction interface in the sample cavity. At the same time, through the total reflection path design, such as the second reflector 6, the light is vertically incident on the silicon crystal surface, maximizing the utilization of light energy and reducing background interference.

[0046] In the specific implementation process, the reflector assembly consists of four gold-plated mirrors (roughness ≤ Ra 0.8μm) forming a closed optical path: the first reflector 5 is tilted toward the infrared light entrance 2, reflecting the incident light to the second reflector 6 at an angle of 45°±5°; the second reflector 6 guides the light upward to the sample cavity and focuses it on the surface of the silicon crystal; the light reflected by the silicon crystal passes through the third reflector 7 and the fourth reflector 8 in turn, forming a total reflection path at a symmetrical angle of 45°, and finally exits from the infrared light exit 3. The high reflectivity (≥95%) of the gold-plated material and the ultra-smooth characteristics of the mirror surface significantly reduce the optical path loss. The four-mirror collaborative design eliminates the spot offset through precise angle control, ensuring efficient transmission of infrared energy, and is suitable for in-situ monitoring of fast transient reactions.

[0047] The gold-plated reflector uses a vacuum gold-plating process to form a uniform and dense gold film (gold-plated layer thickness ≤ 50nm), which significantly reduces the energy loss of infrared light in the propagation path by reducing the mirror reflectivity to ≤ 5% (the traditional aluminum film reflectivity is about 80%). Combined with the 45°±5° inclination design of the second reflector 6 in the optical path, the incident light passes through the mirror obliquely upward and is incident on the surface of the silicon crystal component 13, forming the following technical advantages:

[0048] Enhanced surface and near-surface detection sensitivity: When oblique incident light passes through the sample cavity 12, its penetration depth can reach 2-3μm (3 times higher than vertical incidence), effectively capturing the vibration information of molecules adsorbed on the catalyst surface and shallow reaction intermediates.

[0049] Stimulate the evanescent wave effect: the incident angle and the silicon crystal (refractive index n = 3.9) meet the critical condition of total reflection. The oblique incident light excites the evanescent wave on the surface of the silicon crystal, causing it to propagate along the surface to a depth of about 1-2μm, thereby achieving non-destructive detection of the surface and sub-surface of the sample; Suppress stray light interference: the gold-plated surface roughness of the reflector group is ≤Ra 0.8μm, and the closed optical path design greatly reduces ambient light noise and scattered light, and the signal-to-noise ratio is increased to above 1000:1.

[0050] The accessory housing 1 adopts a modular shell structure, which wraps the reflector assembly and forms a closed optical cavity. The shelf 11 provided on the inner edge of the top opening cooperates with the threaded structure of the removable optical path top plate, which not only ensures the positioning accuracy (tolerance ±0.1mm) when the top plate is embedded, but also achieves IP67-level sealing performance through the compression seal ring 8, which is suitable for high temperature (≤300℃) or corrosive gas environment. The fixed plate 4 integrates the silicon crystal component 13, whose length and width are strictly matched with the housing 1 (error ≤0.2mm) to avoid optical path deviation. At the same time, the nested design of the top plate and the housing 1 effectively blocks external stray light from entering the optical path system, ensuring that the infrared energy is focused on the sample cavity 12 area.

[0051] Application Example 1

[0052] In order to verify the performance advantages of the optical path of the present invention, ethanol was used as the test sample in the experiment, and in-situ infrared spectroscopy characterization was performed under the same instrument conditions (such as the total reflection accessory produced by PIKE and the device of the present invention were connected to the FTIR spectrometer, the scanning range was 4000-400cm-1, the resolution was 4cm-1, and the integration time was 1 second). The results showed that in the same concentration (10% v / v) of ethanol solution, the characteristic absorption peak signal intensity detected by the optical path accessory of the present invention was about 5 times that of the PIKE optical path accessory, and the signal-to-noise ratio (S / N) was significantly improved ( Figure 5 ). This shows that the real-time monitoring capability of the reaction interface changes of the scheme of the present invention is greatly improved. This result is due to the low-loss design of the gold-plated reflector in the optical path (surface roughness ≤ Ra 0.8μm) and the suppression of stray light by the total reflection path, which significantly enhances the infrared energy utilization and signal stability.

[0053] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization, characterized in that: include: A housing (1) having an infrared light inlet (2) and an infrared light outlet (3) provided on its side; A detachable optical path top plate is covered on the outer shell (1), the detachable optical path top plate and the outer shell form a closed space, and the detachable optical path top plate includes a fixing plate (4); A silicon crystal assembly is arranged on the lower surface of the fixing plate (4), and a sample cavity for arranging a catalyst sample is arranged on the silicon crystal assembly; The reflector assembly comprises four reflectors arranged in sequence, wherein the infrared light introduced from the infrared light inlet (2) is incident upward to the surface of the silicon crystal assembly through two of the reflectors, and the infrared light reflected by the silicon crystal surface forms a total reflection path through the two reflectors and is finally emitted from the infrared light outlet (3).

2. A simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 1, characterized in that: The reflector assembly comprises a first reflector (5) and a second reflector (6) arranged on the light-incoming side of the housing (1), and further comprises a third reflector (6) and a fourth reflector (7) arranged on the light-outgoing side of the housing (1); The first reflector (5), the second reflector (6), the third reflector (6) and the fourth reflector (7) all adopt a gold-plated mirror surface, and the mirror surface roughness is ≤Ra 0.8μm; The first reflector (5), the second reflector (6), the third reflector (6) and the fourth reflector (7) are all fixed in the housing (1) via a fixing block with an inclined surface, and the fixing block is connected to the housing (1) via a buckle or a bolt.

3. A simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 2, characterized in that: The first reflector (5) is inclined toward the infrared light inlet (2) and reflects the infrared light to the second reflector (6).

4. A simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 3, characterized in that: The second reflector (6) is used to direct the infrared light to pass through the sample cavity upward and incident on the surface of the silicon crystal component.

5. A simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 4, characterized in that: The third reflector (7) reflects the infrared light reflected by the silicon crystal to the fourth reflector (8).

6. A simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 4, characterized in that: The fourth reflector (7) is used to reflect the infrared light to the infrared light outlet (3) to form a total reflection light path.

7. The simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 3, characterized in that: The lower surface of the detachable optical path top plate is provided with a sealing ring (8) near the edge.

8. The simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 7, characterized in that: The outer shell (1) is a shell structure with an opening at the top, and a shelf (11) is provided at the inner edge of the top opening of the outer shell (1). The fixing plate (4) is covered on the outer shell (1) so that the sealing ring (8) is in close contact with the shelf (11).

9. The simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 1, characterized in that: The silicon crystal assembly comprises a silicon crystal body (12) and a sample cavity, and the silicon crystal body (12) is fixed to the lower surface of the fixing plate (4) by means of fasteners.

10. The simple attenuated total reflection accessory suitable for in-situ infrared spectroscopy characterization according to claim 1, characterized in that: The sample cavity is a groove of 2-3 mm and a quartz glass window that can cover the groove. The sample cavity is arranged on the lower surface of the silicon crystal body (12), and the quartz glass window is connected to the silicon crystal body (12) by a buckle.

Images