Synchronous measurement apparatus for near-infrared spectrum and raman spectrum

Abstract

A synchronous measurement apparatus for a near-infrared spectrum and a Raman spectrum. The apparatus comprises a near-infrared spectrometer (1), a first optical fiber patch cord (2), a first optical fiber adapter (3), a collimating lens (4), a sample platform (7), a coupling lens (8), a second optical fiber adapter (9), a second optical fiber patch cord (12), a laser device (15), a third optical fiber patch cord (13), a Raman probe (10), a fourth optical fiber patch cord (14), a grating spectrometer (16) and a controller (17), wherein the first optical fiber patch cord (2) is connected to the near-infrared spectrometer (1) and the first optical fiber adapter (3); the second optical fiber patch cord (12) is connected to the near-infrared spectrometer (1) and the second optical fiber adapter (9); the collimating lens (4), the sample platform (7) and the coupling lens (8) are arranged between the first optical fiber adapter (3) and the second optical fiber adapter (9); the third optical fiber patch cord (13) is connected to the laser device (15) and the Raman probe (10); the fourth optical fiber patch cord (14) is connected to the grating spectrometer (16) and the Raman probe (10); and the Raman probe (10) and the first optical fiber adapter (3) are located at different heights. A near-infrared spectrum and a Raman spectrum of a sample can be synchronously measured, thereby realizing rapid measurement and analysis of the sample.

Description

Near-infrared spectroscopy and Raman spectroscopy simultaneous measurement device Technical Field

[0001] The present invention relates to the technical field of test equipment, in particular to a near-infrared spectrum and Raman spectrum synchronous measurement device. Background Art

[0002] Currently, near-infrared spectroscopy generally refers to the absorption spectrum of a substance in the near-infrared band. Based on the selective absorption of light of specific wavelengths by a substance, the characteristic absorption peak of a sample in the near-infrared band is detected by measuring the background signal and the transmission signal of a beam of light passing through the sample. Raman spectroscopy, on the other hand, is a scattering signal. Based on the inelastic scattering of the probe light by the sample, the frequency of the scattered light produced by inelastic scattering changes, and the Raman spectrum is obtained by detecting this scattered light. Both near-infrared spectroscopy and Raman spectroscopy can characterize the structural characteristics of a substance's molecules and are therefore widely used in the detection and analysis of substances. However, the two spectra have different physical principles, which can complement each other in substance detection. It has been proven that performing both spectroscopy on the same sample and using them for analysis can provide more accurate detection results.

[0003] During the production of petrochemical products, rapid analysis and evaluation of petrochemical materials is of great significance for controlling the quality of petrochemical products, reducing production costs, and optimizing production processes. Near-infrared spectroscopy and Raman spectroscopy have achieved numerous application results in this field, and the integration of the two facilitates more accurate detection and analysis. However, there is currently little simultaneous near-infrared and Raman spectroscopy detection equipment on the market for petrochemical materials. When detecting near-infrared and Raman spectra, if both spectra cannot be obtained using the same equipment, it is necessary to transfer samples or even repeat sample preparation. This operation carries the risk of introducing a large number of errors and affecting the test results, while also increasing workload and reducing efficiency. For this reason, it is of great significance to achieve simultaneous detection of near-infrared and Raman spectra.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to provide a near-infrared spectrum and Raman spectrum synchronous measurement device to synchronously detect the near-infrared spectrum and Raman spectrum of a sample and realize rapid detection and analysis of the sample.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A near-infrared spectrum and Raman spectrum synchronous measurement device, comprising a near-infrared spectrometer, a first optical fiber jumper, a first optical fiber adapter, a collimating lens, a sample platform, a coupling lens, a second optical fiber adapter, a second optical fiber jumper, a laser, a third optical fiber jumper, a Raman probe, a fourth optical fiber jumper, a grating spectrometer, and a controller, wherein the two ends of the first optical fiber jumper are connected to the near-infrared spectrometer and the first optical fiber adapter, the two ends of the second optical fiber jumper are connected to the near-infrared spectrometer and the second optical fiber adapter, and the collimating lens, the sample platform, the coupling lens, the second optical fiber adapter, the second optical fiber jumper, a laser, a third optical fiber jumper, a Raman probe, a fourth optical fiber jumper, a grating spectrometer, and a controller. The sample platform and the coupling lens are provided, the first fiber optic adapter, the collimating lens, the coupling lens and the second fiber optic adapter are on the same horizontal plane, the sample platform is used to place the sample, the two ends of the third fiber optic jumper are correspondingly connected to the laser and the Raman probe, the two ends of the fourth fiber optic jumper are correspondingly connected to the grating spectrometer and the Raman probe, the output end of the Raman probe points to the sample on the sample platform, the Raman probe and the first fiber optic adapter, the collimating lens, the coupling lens and the second fiber optic adapter are at different heights, and the near-infrared spectrometer and the grating spectrometer are both electrically connected to the controller.

[0008] Preferably, a concave reflecting mirror is further included, wherein the concave reflecting mirror faces the output end of the Raman probe, and the sample on the sample platform is located between the Raman probe and the concave reflecting mirror.

[0009] Preferably, the surface of the concave reflecting mirror is coated with a gold film.

[0010] Preferably, a three-axis translation stage is further included, and the Raman probe is installed on the three-axis translation stage.

[0011] Preferably, a cuvette is further included, and the cuvette is placed on the sample platform, and the cuvette is used for placing the sample.

[0012] Preferably, the near-infrared beam between the first fiber optic adapter and the second fiber optic adapter is perpendicular to the Raman beam of the Raman probe, the angle between the near-infrared beam and the cuvette is 45 degrees, and the angle between the Raman beam and the cuvette is 45 degrees.

[0013] Preferably, the near-infrared spectrometer is a Fourier transform near-infrared spectrometer.

[0014] Preferably, the first optical fiber jumper, the second optical fiber jumper, the third optical fiber jumper, and the fourth optical fiber jumper are all low-hydroxyl silica optical fibers.

[0015] Preferably, the collimating lens and the coupling lens are both made of CaF2.

[0016] Preferably, the cuvette is made of quartz.

[0017] Compared with the prior art, the device for synchronously measuring near-infrared spectroscopy and Raman spectroscopy according to the embodiment of the present invention has the following beneficial effects:

[0018] In the present invention, when detecting the near-infrared spectrum, the near-infrared spectrometer is equipped with a Michelson interferometer, a near-infrared light detector and a control program, which can detect the spectrum curve in the range of 850-2500nm. The near-infrared light beam is emitted from the broadband light source in the near-infrared spectrometer, and the near-infrared light beam is transmitted to the sample detection area of ​​the sample platform through the first optical fiber jumper. The near-infrared light beam is collimated by the collimating lens and passes through the sample, and is coupled to the second optical fiber jumper through the coupling lens and transmitted back to the near-infrared spectrometer for detection. Finally, the near-infrared spectrometer detects the signal. Transmitted to the controller for processing; when detecting the Raman spectrum, the laser emits 785nm monochromatic light, which is first transmitted to the Raman probe through the third optical fiber jumper, and then converged by the lens on the Raman probe to the sample to excite Raman light. The Raman probe can also collect Raman light and detect it through the fourth optical fiber jumper. The Raman probe is composed of a series of optical device components, and its built-in dichroic mirrors, filters and other components can prevent light with a wavelength below 780nm from returning to the grating spectrometer. Finally, the grating spectrometer will further transmit the detected signal to the controller for processing. Since the near-infrared beam and the Raman beam intersect, and the near-infrared beam and the Raman beam are in different height planes, mutual interference between the two can be avoided to achieve synchronous measurement of the sample's near-infrared spectrum and Raman spectrum. There is no need to move the sample or switch the optical path, which avoids errors during sample movement, making the test more convenient, fast and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic diagram of the overall structure of an embodiment of the present invention.

[0020] In the figure, 1. Near-infrared spectrometer; 2. First fiber optic patch cord; 3. First fiber optic adapter; 4. Collimating lens; 5. Cuvette; 6. Concave reflector; 7. Sample platform; 8. Coupling lens; 9. Second fiber optic adapter; 10. Raman probe; 11. Three-axis translation stage; 12. Second fiber optic patch cord; 13. Third fiber optic patch cord; 14. Fourth fiber optic patch cord; 15. Laser; 16. Grating spectrometer; 17. Controller. DETAILED DESCRIPTION

[0021] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0022] In the description of the present invention, it should be understood that the term "comprising" as used in the present specification refers to the presence of the stated features, integers, steps, operations, parts / components, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, parts / components, components, and / or groups thereof. It should be understood that when we refer to a part / component as being "connected" to another part / component, it can be directly connected to the other part / component, or there can be intermediate parts / components. The term "and / or" as used herein includes all or any one of the associated listed items and all combinations thereof.

[0023] As shown in Figure 1, the present invention relates to a synchronous measurement device for near-infrared spectrum and Raman spectrum, including a near-infrared spectrometer 1, a first optical fiber jumper 2, a first optical fiber adapter 3, a collimating lens 4, a sample platform 7, a coupling lens 8, a second optical fiber adapter 9, a second optical fiber jumper 12, a laser 15, a third optical fiber jumper 13, a Raman probe 10, a fourth optical fiber jumper 14, a grating spectrometer 16, and a controller 17. The two ends of the first optical fiber jumper 2 are connected to the near-infrared spectrometer 1 and the first optical fiber adapter 3, and the two ends of the second optical fiber jumper 12 are connected to the near-infrared spectrometer 1 and the second optical fiber adapter 9. The collimating lens 4 is sequentially arranged between the first optical fiber adapter 3 and the second optical fiber adapter 9. lens 4, a sample platform 7 and a coupling lens 8, the first fiber optic adapter 3, the collimating lens 4, the coupling lens 8 and the second fiber optic adapter 9 are on the same horizontal plane, the sample platform 7 is used to place the sample, the two ends of the third fiber optic jumper 13 are correspondingly connected to the laser 15 and the Raman probe 10, the two ends of the fourth fiber optic jumper 14 are correspondingly connected to the grating spectrometer 16 and the Raman probe 10, the output end of the Raman probe 10 points to the sample on the sample platform 7, the Raman probe 10 and the first fiber optic adapter 3, the collimating lens 4, the coupling lens 8 and the second fiber optic adapter 9 are at different heights, and the near-infrared spectrometer 1 and the grating spectrometer 16 are both electrically connected to the controller 17.

[0024] In the present invention, when detecting the near-infrared spectrum, the near-infrared spectrometer 1 is equipped with a Michelson interferometer, a near-infrared light detector, and a control program, which can detect the spectrum curve in the range of 850-2500nm. The near-infrared light beam is emitted from the broadband light source in the near-infrared spectrometer 1, and the near-infrared light beam is transmitted to the sample detection area of ​​the sample platform 7 through the first optical fiber jumper 2. The near-infrared light beam is collimated by the collimating lens 4 and passes through the sample. It is coupled to the second optical fiber jumper 12 through the coupling lens 8 and is transmitted back to the near-infrared spectrometer 1 for detection. Finally, the near-infrared spectrometer 1 transmits the detected signal to the controller 17. When processing and detecting the Raman spectrum, the laser 15 emits 785nm monochromatic light. The laser is first transmitted to the Raman probe 10 through the third optical fiber jumper 13, and then is focused by the lens on the Raman probe 10 to the sample to excite Raman light. The Raman probe 10 can also collect Raman light, and it is detected by the grating spectrometer 16 through the fourth optical fiber jumper 14. The Raman probe 10 is composed of a series of optical device components. Its built-in dichroic mirrors, filters and other components can prevent light with a wavelength below 780nm from returning to the grating spectrometer 16. Finally, the grating spectrometer 16 further transmits the detected signal to the controller 17 for processing. Since the near-infrared beam and the Raman beam intersect, and the near-infrared beam and the Raman beam are in different height planes, mutual interference between the two can be avoided to achieve synchronous measurement of the sample's near-infrared spectrum and Raman spectrum. There is no need to move the sample or switch the optical path, which avoids errors during sample movement, making the test more convenient, fast and accurate.

[0025] The near-infrared spectrum and Raman spectrum synchronous measurement device also includes a concave reflector 6, which is opposite to the output end of the Raman probe 10. The sample on the sample platform 7 is located between the Raman probe 10 and the concave reflector 6, and the surface of the concave reflector 6 is coated with a gold film.

[0026] Specifically, the concave reflector 6 has a focal length of 20 mm and is coated with a gold film on its surface, so it has high reflectivity over a wide spectral range. The concave reflector 6 faces the output end of the Raman probe 10 to couple the Raman light scattered after passing through the sample into the Raman probe 10. At the same time, the 785 mm laser is refocused onto the sample to excite the Raman light again, which is beneficial to enhance the Raman signal.

[0027] The device for synchronously measuring near-infrared spectroscopy and Raman spectroscopy further includes a three-axis translation stage 11 , and the Raman probe 10 is mounted on the three-axis translation stage 11 .

[0028] By placing the Raman probe 10 on a three-axis translation stage 11 , the position of the Raman probe 10 can be adjusted in the horizontal direction and the height direction, so that the Raman light and the near-infrared light beam are in different height planes, thereby avoiding influence.

[0029] The device for synchronously measuring near-infrared spectroscopy and Raman spectroscopy further includes a cuvette 5 , which is placed on the sample platform 7 . The cuvette 5 is used for placing samples and is made of quartz.

[0030] The sample is placed in a cuvette 5, and the cuvette 5 is placed on the sample platform 7, so that the user can select cuvettes 5 of different sizes and adjust the placement angle of the cuvette 5, thereby making sample detection more flexible. In addition, the cuvette 5 is made of quartz material, and its transmittance in the range of 300-3500nm is greater than 80%, which can meet the wavelength requirements of spectral detection.

[0031] In this embodiment, the near-infrared beam between the first optical fiber adapter 3 and the second optical fiber adapter 9 is perpendicular to the Raman beam of the Raman probe 10, the angle between the near-infrared beam and the cuvette 5 is 45 degrees, and the angle between the Raman beam and the cuvette 5 is 45 degrees.

[0032] Specifically, different models of cuvette 5 can be selected according to the absorption spectrum properties of the sample. When the sample has weak absorption in the near-infrared band, a long optical path cuvette 5 can be used, such as a square cross-section (10mm×10mm) cuvette 5 with light passing on all four sides. At this time, the cuvette 5 can be placed perpendicular to the near-infrared light beam; when the sample has strong absorption in the near-infrared band, the optical path can be reduced to avoid absorption saturation. Taking the small optical path 1mm single-sided light-transmitting cuvette 5 as an example, this type of cuvette 5 is difficult to make transparent on all four sides. In order to achieve synchronous detection of two beams of light, the solution adopted by the present invention is to adjust the cuvette 5 to close to 45 degrees; the sample platform 7 can be compatible with the placement of cuvettes 5 of different models and realize the control of the installation angle. This solution expands the range of detectable samples.

[0033] In this embodiment, the near-infrared spectrometer 1 is a Fourier transform near-infrared spectrometer.

[0034] In this embodiment, the first optical fiber jumper 2, the second optical fiber jumper 12, the third optical fiber jumper 13, and the fourth optical fiber jumper 14 are all low-hydroxyl quartz optical fibers, and the collimating lens 4 and the coupling lens 8 are both made of CaF2 material, which has a small loss within the target near-infrared wavelength detection range; the focal length of the collimating lens 4 is selected to be 10 mm, and the focal length of the coupling lens 8 is 35 mm.

[0035] In actual measurement, the present application can be compatible with detecting near-infrared spectra or Raman spectra separately. When detecting near-infrared spectra, after starting the Fourier transform near-infrared spectrometer, according to the Beer-Lambert absorption law, it is first necessary to collect the background signal when there is no sample absorption. At this time, an empty cuvette 5 can be placed at the target position, and then the cuvette 5 containing the sample is replaced for signal detection. The control program of the Fourier transform near-infrared spectrometer can be used to obtain the corresponding signal and process it, and finally the near-infrared spectrum of the sample can be obtained. When detecting Raman spectra, it is necessary to avoid the influence of changes in ambient light as much as possible. For this purpose, the entire detection area is designed with a light shield to block the changing ambient light. After starting the laser 15 and the grating spectrometer 16, it is first necessary to collect the background signal when there is no sample. At this time, an empty cuvette 5 is placed at the target position, and then the cuvette 5 containing the sample is replaced for signal detection. The background signal needs to be subtracted. The control program of the grating spectrometer 16 can obtain the corresponding signal and process it, and finally the Raman spectrum can be obtained. When detecting two spectra at the same time, the steps are basically the same as above.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A device for simultaneous measurement of near-infrared spectroscopy and Raman spectroscopy, characterized in that: The device comprises a near-infrared spectrometer, a first optical fiber jumper, a first optical fiber adapter, a collimating lens, a sample platform, a coupling lens, a second optical fiber adapter, a second optical fiber jumper, a laser, a third optical fiber jumper, a Raman probe, a fourth optical fiber jumper, a grating spectrometer, and a controller. The two ends of the first optical fiber jumper are connected to the near-infrared spectrometer and the first optical fiber adapter, and the two ends of the second optical fiber jumper are connected to the near-infrared spectrometer and the second optical fiber adapter. The collimating lens, the sample platform, and the coupling lens are sequentially arranged between the first optical fiber adapter and the second optical fiber adapter. The first fiber optic adapter, the collimating lens, the coupling lens, and the second fiber optic adapter are on the same horizontal plane; the sample platform is used to place the sample; the two ends of the third fiber optic jumper are correspondingly connected to the laser and the Raman probe; the two ends of the fourth fiber optic jumper are correspondingly connected to the grating spectrometer and the Raman probe; the output end of the Raman probe points to the sample on the sample platform; the Raman probe and the first fiber optic adapter, the collimating lens, the coupling lens, and the second fiber optic adapter are at different heights; the near-infrared spectrometer and the grating spectrometer are both electrically connected to the controller.

2. The device for simultaneous measurement of near-infrared spectroscopy and Raman spectroscopy according to claim 1, characterized in that: It also includes a concave reflecting mirror, which is opposite to the output end of the Raman probe. The sample on the sample platform is located between the Raman probe and the concave reflecting mirror.

3. The device for simultaneous measurement of near-infrared spectroscopy and Raman spectroscopy according to claim 2, characterized in that: The surface of the concave reflecting mirror is plated with a gold film.

4. The device for simultaneous measurement of near infrared spectroscopy and Raman spectroscopy according to claim 1, characterized in that: It also includes a three-axis translation platform, and the Raman probe is installed on the three-axis translation platform.

5. The near infrared spectrum and Raman spectrum synchronous measurement device according to claim 1, characterized in that: It also includes a cuvette, which is placed on the sample platform and is used for placing samples.

6. The device for simultaneous measurement of near-infrared spectroscopy and Raman spectroscopy according to claim 5, characterized in that: The near-infrared beam between the first optical fiber adapter and the second optical fiber adapter is perpendicular to the Raman beam of the Raman probe, the angle between the near-infrared beam and the cuvette is 45 degrees, and the angle between the Raman beam and the cuvette is 45 degrees.

7. The device for simultaneous measurement of near infrared spectrum and Raman spectrum according to claim 1, characterized in that: The near-infrared spectrometer is a Fourier transform near-infrared spectrometer.

8. The device for simultaneous measurement of near infrared spectrum and Raman spectrum according to claim 1, characterized in that: The first optical fiber jumper, the second optical fiber jumper, the third optical fiber jumper, and the fourth optical fiber jumper are all low-hydroxyl silica optical fibers.

9. The device for simultaneous measurement of near infrared spectrum and Raman spectrum according to claim 1, characterized in that: The collimating lens and the coupling lens are both made of CaF2.

10. The device for simultaneous measurement of near infrared spectrum and Raman spectrum according to claim 5, characterized in that: The cuvette is made of quartz material.

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