A spectral measurement device and its detection method

Abstract

The present invention discloses a measurement spectroscopic device, which includes a tungsten lamp, a shutter, a first coupling system, a sample holder, a second coupling system, a one-to-two optical fiber, an ultraviolet-visible spectrometer, a near-infrared spectrometer, and a minimum Raman system. The present invention also discloses a detection method for the measurement spectroscopic device, which includes the following steps: opening the shutter, after the tungsten lamp light passes through the first coupling system, different characteristic peaks are generated after passing through the sample, and through the second coupling system, the broadband light beam is divided into two beams of light by the one-to-two optical fiber, and then incident on the ultraviolet-visible spectrometer and the near-infrared spectrometer; and / or, the shutter blocks the tungsten lamp, the minimum Raman system is enabled, the laser passes through the confocal coupling system and then is incident on the sample, and then the Raman signal returns along the original path, passes through the confocal coupling system, and finally is incident on the Raman spectrometer. The measurement spectroscopic device of the present invention can measure ultraviolet-visible spectra, infrared spectra, and Raman spectra at the same time, and can reduce costs while improving measurement efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of measurement spectroscopic devices. Specifically, it relates to a measurement spectroscopic device that combines ultraviolet-visible spectroscopy, near-infrared spectroscopy, and Raman spectroscopy, as well as a detection method therefor. Background Art

[0002] Ultraviolet-visible spectrometers can establish qualitative, quantitative, and structural analyses based on the absorption characteristics of substance molecules in the ultraviolet and visible bands, and are widely used in the determination of various chemical substances, such as the verification of compounds, purity inspection, determination of isomers, determination of steric effects, determination of hydrogen bond strength, etc. Therefore, ultraviolet-visible spectrometers are a commonly used auxiliary analysis method.

[0003] The near-infrared band is exactly in the overtone and combination frequency absorption regions of hydrogen-containing groups in some chemical substances, which has led to the rapid development of near-infrared spectrometers in recent years and their wide application in fields such as food, chemical industry, and textiles.

[0004] A Raman spectrometer is a spectrometer based on the Raman effect. In 1928, Raman first observed in the laboratory that when monochromatic light is incident on a substance, inelastic scattering spectra are generated. This phenomenon where the scattered light has a different frequency from the incident light is called Raman scattering. The Raman scattering effect is closely related to the molecular structure and is a fingerprint spectrum that can characterize molecular structure information, and can extract data information on molecular vibration and rotation, thereby further studying the molecular structure. The Raman technique uses a non-invasive method when detecting samples, so it is convenient to operate and the detection is rapid (Application of Portable Raman Spectrometer in the Field of Precursor Chemicals, Analytical Chemistry, 20190110).

[0005] When the above three spectrometers are used independently, they all have wide applications in their respective fields, but there are limitations in independent use. For example, when measuring a sample, a single ultraviolet-visible spectrometer or near-infrared spectrometer cannot reflect Raman information; similarly, a single Raman spectrometer cannot reflect ultraviolet-visible and near-infrared band information. In order to increase the spectral range, in recent years, a combined type of near-infrared spectrometer and Raman spectrometer has been developed, which can simultaneously reflect the near-infrared spectrum and Raman spectrum information of a sample. However, currently, no type that can incorporate the ultraviolet-visible light band has been seen on the market, resulting in the lack of spectral information of an article in the ultraviolet-visible band when measuring a sample.

[0006] In addition, when spectrometers are combined, the detectors of different spectrometers overlap in some bands, but the response efficiencies are different. Then which detector's feedback signal should be finally adopted for the sample is also a problem faced by the system when collecting signals. Summary of the Invention

[0007] The object of the present invention is to provide a spectral measurement device to solve the problems of missing spectral information in some bands of existing spectral measurement devices and the inability to determine which CCD feedback signal to use in the overlapping band regions.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] As a first aspect of the present invention, a spectral measurement device includes a tungsten lamp, a first coupling system, a sample holder for placing a sample, a second coupling system, a one-to-two optical fiber, an ultraviolet-visible spectrometer, a near-infrared spectrometer, and a minimum Raman system. A shutter for switching light sources is provided between the sample holder and the first coupling system.

[0010] When the shutter is open, after the tungsten lamp light passes through the first coupling system, different characteristic peaks are generated after passing through the sample on the sample holder. Through the second coupling system, the broadband light beam is split into two beams by the one-to-two optical fiber and then incident on the ultraviolet-visible spectrometer and the near-infrared spectrometer.

[0011] When the shutter blocks the tungsten lamp, the minimum Raman system is enabled. The laser passes through the equal-focus coupling system and then is incident on the sample on the sample holder. Then the Raman signal returns along the original path, passes through the equal-focus coupling system, and finally is incident on the Raman spectrometer.

[0012] According to the present invention, the spectral measurement device further includes a power supply module, which is respectively connected to the tungsten lamp and the laser light source for power supply.

[0013] According to the present invention, the spectral measurement device further includes a PC / control module and a USB. The USB is electrically connected to the PC / control module, and the USB is respectively connected to the ultraviolet-visible spectrometer, the near-infrared spectrometer, and the Raman spectrometer.

[0014] According to the present invention, the ultraviolet-visible spectrometer includes a first slit, a first concave mirror, a first reflection grating, a second concave mirror, and a first detector. During use, the light beam is incident on the first concave mirror through the first slit, then is collimated and incident on the first reflection grating, and after dispersion, is focused on the first detector by the second concave mirror. The spectral range detected by the first detector is 350 - 1050 nm.

[0015] According to the present invention, the near-infrared spectrometer includes a second slit, a first convex lens, a first transmission grating, a third concave mirror, and a second detector. During use, the light beam is incident on the first convex lens through the second slit, then is collimated and incident on the first transmission grating, and after dispersion, is focused on the second detector by the third concave mirror. The spectral range detected by the second detector is 900 - 1700 nm.

[0016] According to the present invention, the minimum Raman system includes an isofocal coupling system and a Raman spectrometer. The isofocal coupling system includes a laser light source, a first aperture, a narrow bandpass filter, a dichroic mirror, a first total reflector, a second total reflector, a second aperture, a third convex lens, a long pass filter, and a fourth convex lens. Among them, the laser light source is a 785 nm laser, which emits laser light. After being collimated by the second convex lens, passing through the first aperture and the narrow bandpass filter, being reflected by the dichroic mirror, being reflected by the first total reflector and the second total reflector, and passing through the second aperture and the third convex lens, the light is focused on the sample center in the sample holder to generate a Raman beam. The Raman beam returns to the original optical path, is collimated by the third convex lens, passes through the second total reflector and the first total reflector, passes through the dichroic mirror, and is focused by the fourth convex lens after passing through the long pass filter. The focused light is incident on the Raman spectrometer. That is, the focused light is incident on the fourth concave mirror for collimation after passing through the third slit, is incident on the second reflection grating, and after dispersion, is focused on the third detector by the fifth concave mirror.

[0017] According to the present invention, the first coupling system includes a first collimator, an optical fiber, and a second collimator arranged in sequence. The collimator collimates or focuses the tungsten lamp, and the optical fiber plays a role in transmitting the light beam.

[0018] According to the present invention, the second coupling system includes a third collimator.

[0019] According to the present invention, a one-to-two optical fiber is used to divide a beam of light into two beams of light. The cores of the two bifurcated optical fibers are arranged in a 19*1 structure, that is, a single longitudinal arrangement structure. When arranging, several cores close to the center in the non-bifurcated optical fiber are placed in the central region of the bifurcated optical fiber, and the other cores close to the edge are placed in the edge region of the bifurcated optical fiber. These designs ensure that when the tail of the bifurcated optical fiber is matched with the SMA connector of the spectrometer, the light emitted vertically matches the shape of the subsequent slit of the spectrometer, maximizing the light flux incident into the spectrometer. This is also the basis and guarantee for the mainframe to increase the ultraviolet-visible band range.

[0020] According to the present invention, the first reflection grating in the ultraviolet-visible spectrometer is a plane ruled reflection grating.

[0021] According to the present invention, the first transmission grating in the near-infrared spectrometer is a transmission grating.

[0022] According to the present invention, for the Raman spectrometer in the minimum Raman system, its second reflection grating is a plane ruled reflection grating.

[0023] According to the present invention, both the second total reflector and the first total reflector are set at 45 degrees.

[0024] According to the present invention, the emitted light spot of the laser light source is a vertical light spot. The second convex lens, the third convex lens, and the fourth convex lens have the same focal length. Combining the first aperture and the second aperture together forms an isofocal design system for the vertical light spot. After the sample receives the laser of the isofocal coupling system, a first converging beam is reflected. The first converging beam passes through the third convex lens, the second aperture, the second total reflector, the first total reflector, the dichroic sheet, the long-pass filter, and the fourth convex lens of the isofocal coupling system and is focused to form a second converging beam. The laser light source and the first converging beam converge to a vertical point in the sample, and the second converging beam converges to a vertical point on the third slit conjugately.

[0025] As a second aspect of the present invention, the detection method of the measurement spectral device described above includes the following steps:

[0026] When the shutter is opened, after the tungsten lamp light passes through the first coupling system, different characteristic peaks are generated after passing through the sample on the sample holder. Through the second coupling system, the broadband light beam is divided into two beams by a one-to-two optical fiber and then incident on the ultraviolet-visible spectrometer and the near-infrared spectrometer to reflect the ultraviolet-visible and near-infrared band information of the substance to be measured; and / or,

[0027] When the tungsten lamp is blocked by the shutter and the minimum Raman system is enabled, the laser passes through the isofocal coupling system and is incident on the sample on the sample holder. Then the Raman signal returns along the original path, passes through the isofocal coupling system, and finally is incident on the Raman spectrometer to reflect the Raman spectral information of the substance to be measured.

[0028] According to the present invention, a spectrum splicing algorithm is performed on the spectra detected by the ultraviolet-visible spectrometer and the near-infrared spectrometer to splice the two spectra into one spectrum.

[0029] Further, the formula of the spectrum splicing algorithm is:

[0030] M = N1 x (1000 - N) / 200 + N2 x (N - 800) / 200

[0031] Wherein, N is between (800nm, 1000nm), N1 is the ordinate value of N in the ultraviolet-visible spectrometer, and N2 is the ordinate value of N in the near-infrared spectrometer.

[0032] The measurement spectral device and its detection method of the present invention have the following beneficial effects:

[0033] 1. While combining the near-infrared spectrometer and the Raman spectrometer, the ultraviolet and visible bands are added. The method is to add a flexible one-to-two optical fiber. Since the bifurcated optical fibers are selected in a specific order and arranged vertically in a single row, a beam of light can be evenly divided into two beams and coupled to the slit with the maximum efficiency to dock with the subsequent two corresponding spectrometers. The signal range of the ultraviolet and visible bands is increased.

[0034] 2. The setting of the one-to-two optical fiber divides the broadband spectrometer into two spectrometers to indirectly improve the resolution.

[0035] 3. The minimum Raman system adopts pure spatial light transmission and uses a "Z"-type turn to avoid interfering light and stray light. The coupling system in it performs a confocal design on the vertical light spot of the laser. Compared with the optical path using fiber transmission, this system can receive weaker Raman signals.

[0036] 4. The spectral stitching technology of the CCD overlapping band is adopted. The same band range has different response efficiencies on different CCDs. In order to truly reflect the signal of the object to be measured, the present invention performs a new software algorithm with selected weights in the overlapping area to achieve multispectral fusion.

[0037] 5. This measurement spectral device can measure ultraviolet-visible spectra, infrared spectra and Raman spectra at the same time, and can reduce the cost of purchasing three spectral measurement devices while improving the measurement efficiency.

[0038] 6. In the minimum Raman system, after the laser is emitted, it is collimated by a second convex lens, and then a narrowband pass filter is used to further purify the laser wavelength to achieve the purpose of compressing the bandwidth. The long-pass filter is used to transmit the Raman spectrum generated by the sample. Brief Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of the measurement spectral device combining ultraviolet-visible spectrum, near-infrared spectrum and Raman spectrum of the present invention.

[0040] Figure 2 It is a cross-sectional view of the one-to-two optical fiber of the present invention before being split.

[0041] Figure 3 It is a cross-sectional view of the one-to-two optical fiber of the present invention after being split.

[0042] Figure 4 It is the response curve of the first detector.

[0043] Figure 5 It is the response curve of the second detector.

[0044] Figure 6 It is the curve when the first detector and the second detector overlap at 800 - 1000 nm.

[0045] Figure 7 It is the architecture diagram.

[0046] Figure 8(A) is the original Raman spectrum of oil samples with different mixing ratios;

[0047] Figure 8(B) is the original ultraviolet-visible and near-infrared spectrum diagram of oil samples with different mixing ratios.

[0048] Figures 9(A), 9(B), 9(C), and 9(D) are respectively graphs showing the relationship between the angular value and the mass ratio of extra-virgin olive oil for the pre-Raman-intercepted band, the post-Raman-intercepted band, the total Raman-intercepted band, and the visible original data.

[0049] Figure 10 It is a graph showing the relationship between the angular value and the mass ratio of extra-virgin olive oil for the pre-Raman-band fused data.

[0050] Figure 11 It is a graph showing the relationship between the angular value and the mass ratio of extra-virgin olive oil for the total Raman-intercepted band fused data.

[0051] Explanation of figure numbers:

[0052] 1. Tungsten lamp; 2. Sample holder; 3. Shutter;

[0053] 41. Optical fiber; 42. One-to-two optical fiber;

[0054] 5. UV-visible spectrometer; 51. First slit; 52. First concave mirror; 53. Second concave mirror; 54. First reflection grating; 55. First detector;

[0055] 6. Near-infrared spectrometer; 61. Second slit; 62. First convex lens; 63. First transmission grating; 64. Third concave mirror; 65. Second detector;

[0056] 7. Minimum Raman system; 71. Raman spectrometer; 711. Third slit; 712. Fourth concave mirror; 713. Fifth concave mirror; 714. Second reflection grating; 715. Third detector;

[0057] 720. Laser light source; 721. First aperture; 722. Narrow-band pass filter; 723. Dichroic mirror; 724. First total reflection mirror; 725. Second total reflection mirror; 726. Second aperture; 727. Third convex lens; 728. Long-wave pass filter; 729. Fourth convex lens; 7201. Second convex lens;

[0058] 81. First collimator; 82. Second collimator; 83. Third collimator;

[0059] 91. Broad-spectrum light beam; 92. Collimated light beam; 93. Emitted light beam; 94. Single-frequency divergent laser; 95. First converging light beam; 96. Second converging light beam. Specific embodiments

[0060] The following further details the measurement spectral device and its detection method combining ultraviolet-visible spectroscopy, near-infrared spectroscopy, and Raman spectroscopy of the present invention with reference to specific drawings.

[0061] The CCD in this embodiment refers to the detector.

[0062] As Figure 1 shown, the spectral measurement device of the present invention applicable to measuring ultraviolet-visible spectra, near-infrared spectra, and Raman spectra includes: a tungsten lamp 1, a first coupling system, a sample holder 2, a stop 3, a second coupling system, a one-to-two optical fiber 42, an ultraviolet-visible spectrometer 5, a near-infrared spectrometer 6, and a minimum Raman system 7. The first coupling system includes a first collimator 81, a second collimator 82, and an optical fiber 41. The second coupler includes a third collimator 83. The ultraviolet-visible spectrometer 5 selected in this embodiment is a 350-1050 nm spectrometer, the near-infrared spectrometer 6 is a 900-1700 nm spectrometer. The minimum Raman system 7 includes an equal-focus coupling system 72 and a Raman spectrometer 71. The laser light source is a 785 nm laser light source.

[0063] Among them, the stop contained in the sample holder adopts a simple insert design: one end of the insert is opaque and the other end is transparent, and it is in the shape of a round hole.

[0064] Among them, the equal-focus coupling system 72 includes a laser light source 720, a first diaphragm 721, a narrow-band pass filter 722, a dichroic mirror 723, a first total reflection mirror 724, a second total reflection mirror 725, a second diaphragm 726, a third convex lens 727, a long-wave pass filter 728, and a fourth convex lens 729.

[0065] When the spectral measurement device of the present invention measures ultraviolet-visible spectra and near-infrared spectra, place the circular light-transmitting hole of the stop 3 in the optical path and use the ultraviolet-visible spectrometer 5 and the near-infrared spectrometer 6. When measuring Raman spectra, place the opaque end of the stop 3 in the optical path, and then the Raman spectrum of the sample is incident on the Raman spectrometer inside the minimum Raman spectrometer.

[0066] When the spectral measurement device of the present invention measures ultraviolet-visible spectra and near-infrared spectra, refer to Figure 1 , place the sample to be measured on the sample holder 2 of the spectral measurement device of the present invention, and turn on the tungsten lamp 1 to emit a broadband beam 91. Then, this broadband beam 91 is converged into a spot with the smallest radius by the first collimator 81 and hits the end face of the optical fiber 41. The optical fiber 41 transmits the light without loss and then emits it in a divergent shape. Then, the divergent beam is converged into a collimated beam 92 by the second collimator 82. The collimated beam 92 is incident into the sample holder 2. When the stop 3 is open, the beam directly hits the sample on the sample holder 2. At this time, the different chromophores contained in the molecules of the sample to be measured will show their characteristic absorption peaks at different wavelengths. The collimated beam 92 passing through the sample continues to be focused on the one-to-two optical fiber 42 by the third collimator 83.

[0067] Refer to Figure 2, the one-to-two optical fiber 42 is specially customized. The number of fiber cores is 38, and 19 A's and 19 B's as shown in Figure 2 are marked out evenly and alternately on the cross-section. Refer to Figure 3 , take 19 A's as the first bifurcation and 19 B's as the second bifurcation; the fiber cores of the two bifurcated optical fibers are arranged in a 19*1 structure, that is, a single longitudinal arrangement structure; when arranging, place several fiber cores close to the center in the non-bifurcated optical fiber in the central area of the bifurcated optical fiber, and place the other fiber cores close to the edge in the edge area of the bifurcated optical fiber; these designs ensure that when the tail of the bifurcated optical fiber is matched with the SMA connector of the spectrometer, the light emitted vertically matches the slit shape of the subsequent spectrometer, maximizing the light flux incident into the spectrometer. This is also the basis and guarantee for the main unit to broaden the spectral range.

[0068] The ultraviolet-visible spectrometer 5 includes a first slit 51, a first concave mirror 52, a second concave mirror 53, a first reflection grating 54, and a first detector 55. Refer to Figure 1 , the light emitted from the tail of the first bifurcated optical fiber is a divergent beam 93. After passing through the first slit 51, a slender beam is obtained. When it is incident on the first concave mirror 52, the beam is collimated into parallel light. When this parallel light is incident on the first reflection grating 54 to produce dispersion, it continues to hit the second concave mirror 53 and then is focused on the first detector 55. This spectrometer can measure the spectral range of 350 - 1050 nm.

[0069] The near-infrared spectrometer 6 includes a second slit 61, a first convex lens 62, a first transmission grating 63, a third concave mirror 64, and a second detector 65. Refer to Figure 1 , the light emitted from the tail of the second bifurcated optical fiber is a divergent beam 93. After passing through the second slit 61, a slender beam is obtained. When it is incident on the first convex lens 62, the beam is collimated into parallel light. When this parallel light is dispersed after passing through the first transmission grating 63, it continues to hit the third concave mirror 64 and then is focused on the second detector 65. This spectrometer can measure the spectral range of 900 - 1700 nm.

[0070] Among them, the spectral ranges of the ultraviolet-visible spectrometer 5 and the near-infrared spectrometer 6 have an overlapping area. For the spectral range of the overlapping area, we use the spectral stitching algorithm for the spectra measured by the first detector 55 and the second detector 65. The spectral stitching algorithm refers to the process of stitching two spectra into one spectrum. The reason for adopting this method is that different detectors have different response sensitivities to different wavelength bands. Figure 4 is the response curve of the first detector 55, Figure 5 is the response curve of the second detector 65. Figure 6Specifically shows the overlap of two CCDs in the range of 800 - 1000 nm, and the responses of the CCDs in this region are different. To perform spectral stitching calculations for the range of 800 - 1000 nm, we use the data of the first detector before 800 nm, the data of the second detector after 1000 nm, and for the range between 800 - 1000 nm, the data of the first detector and the second detector are superimposed proportionally for evaluation.

[0071] Figure 6 In it, the left triangle is the proportion of the first detector and the right triangle is the proportion of the second detector. Specifically: the abscissa interval of 800 nm - 1000 nm is evenly divided into 200 points. The ordinate value of the first point is taken as 99% of the data of the first detector plus 1% of the data of the second detector; the ordinate value of the third point is taken as 98% of the data of the first detector plus 2% of the data of the second detector; at 900 nm, the weights of the two detectors are each taken as 50%, and so on.

[0072] The specific algorithm is as follows. For a point with a wavelength of N, the ordinate value after spectral stitching is

[0073] M = N1 x (1000 - N) / 200 + N2 x (N - 800) / 200

[0074] where N is between (800 nm, 1000 nm), N1 is the ordinate value of N in the first spectrometer, and N2 is the ordinate value of N in the second spectrometer.

[0075] In this way, the purpose of stitching the spectrum can be achieved. The finally obtained curve is relatively smooth, without sudden changes in the peak shape, and is closer to the continuous peak shape of the real substance.

[0076] By using the above-mentioned ultraviolet-visible spectrometer 5 and near-infrared spectrometer 6 in combination, the positions of the absorption peaks in the absorption spectrum of the sample to be measured can be analyzed.

[0077] Reference Figure 1In the minimum Raman system, when the baffle 3 blocks the tungsten lamp 1 and the minimum Raman system 7 is enabled at the same time, a single-frequency divergent laser 94 is emitted from the 785nm laser light source (for example, a 785nm laser) 720, which is converged into a parallel beam by the second convex lens 7201, and then filtered by the first aperture 721 and the narrow-band filter 722 to form a beam with a narrow passband. This beam continues to be incident on the dichroic plate 723 and is reflected to the first total reflection mirror 724 placed at 45 degrees, and the beam is deflected 90 degrees to the left; it continues to hit the second total reflection mirror 725 placed at 45 degrees, and the beam is deflected upward again by 90 degrees. The two total reflection mirrors make the light path form a "Z"-shaped light path, realize the objective translation of the light beam, and cleverly avoid interference light and stray light in the Raman effect. The light beam is incident on the third convex lens 727 through the second aperture 726 for convergence, and is incident on the sample in the sample holder 2. After receiving the laser, the sample produces a Raman effect and reflects the Raman light, i.e., the first convergent light beam 95. The Raman signal returns along the original path (the first convergent light beam 95) through the third convex lens 727, the second aperture 726, the second total reflection mirror 725, the first total reflection mirror 724, and the dichroic plate 723, and then continues to be transmitted to the long-wave pass plate 728 and the fourth convex lens 729 to focus to form the second convergent light beam 96, which enters the Raman spectrometer 71 through the third slit 711. The basic principle of entering the Raman spectrometer is basically the same as that of the ultraviolet-visible spectrometer 5, and plays the role of measuring the Raman spectrum. The Raman spectrometer 71 includes a third slit 711, a fourth concave mirror 712, a fifth concave mirror 713, a second reflection grating 714, and a third detector 715, reference Figure 1 The second convergent light beam 96 passes through the third slit 711 to obtain a thin and long light beam. When it is incident on the fourth concave mirror 712, the light beam is collimated into parallel light. When this parallel light is incident on the second reflection grating 714, it is dispersed, and then it continues to hit the fifth concave mirror 713 and is focused on the third detector 715. This spectrometer can measure the spectrum range of 900 to 1700 nm.

[0078] Since the laser emits a vertical light spot, it is conjugate with the vertical point where the first converging light beam 95 converges into the sample and the vertical point where the second converging light beam 96 converges into the third slit; and the second convex lens 7201, the third convex lens 727, and the fourth convex lens 729 are convex lenses of the same model (i.e., they have the same focal length), which together with the first aperture 721 and the second aperture 726 for blocking stray light form an equal-focal design system for the vertical light spot.

[0079] Figure 7This is the architecture diagram of the system. After the tungsten lamp light passes through the first coupling system, it passes through the sample, the second coupling system, and is incident on the ultraviolet-visible spectrometer 5 and the near-infrared spectrometer 6 through the 1×2 optical fiber 42. The laser light source 720 is incident on the sample after passing through the afocal coupling system. The Raman light generated by the sample returns along the original path to the afocal coupling system and is incident on the Raman spectrometer. The power supply module is electrically connected to the tungsten lamp 1 and the laser light source 720 respectively, and is used to supply power to the two light sources. The PC / control module is connected to the ultraviolet-visible spectrometer, the near-infrared spectrometer, and the Raman spectrometer simultaneously using USB.

[0080] In Example 1, using this measurement system, we carried out quantitative analysis of different grades of olive oil doping.

[0081] The collection object was the mixed olive oil of extra-virgin olive oil #72 and olive pomace oil #39. The mixing ratios are shown in Table 1.

[0082] Table 1 Mixing ratio table of mixed olive oil

[0083]

[0084]

[0085] For these five mixtures, ultraviolet-visible spectra, near-infrared spectra, and Raman spectra were collected multiple times respectively. After data processing, the original spectra are shown in Figures 8(A) and 8(B).

[0086] The ultraviolet-visible light spectral range is from 320 nm to 730 nm; the Raman spectral range is from 800 cm -1 to 1820 cm -1 , 2730 cm -1 to 3100 cm -1 ; the Raman spectral data are divided into the front band 800 cm -1 to 1820 cm -1 , the rear band 2730 cm -1 to 3100 cm -1 and the total intercepted band 800 cm -1 to 1820 cm -1 , 2730 cm -1 to 3100 cm -1。It can be seen that the reasonable optical path design makes the Raman spectrum peaks of the final output obvious, with almost no stray light interference; there are two obvious sharp peaks in the ultraviolet-visible band, increasing the recognizable features of the sample to be measured compared with other types of spectrometers; in addition, the reasonable spectral stitching algorithm at the infrared overlap makes the peak shape in the overlap area smooth, more in line with the actual situation, and avoids the sudden change of the curves between different CCDs. The ultraviolet-visible near-infrared and Raman intercepted data are respectively subjected to angle conversion processing and analysis, and the results shown in Fig. 9(A), Fig. 9(B), Fig. 9(C), and Fig. 9(D) are obtained.

[0087] The data is second-order differentiated (refer to "A Qualitative Method for Vegetable Oils Based on Near-Infrared-Raman Hyphenation", Patent Publication No. CN111458309A, 20200728). The window widths of the front and rear bands of the Raman spectrum are 38, the total intercepted band window width is 88, and the visible spectrum data processing window width is 48. It can be seen from the results that after data processing of the front intercepted band of Raman, the total intercepted band of Raman and the visible original spectrum, the angle values and the mass ratio of extra-virgin olive oil both show a good linear relationship. Therefore, the front intercepted band of Raman and the total intercepted band of Raman are respectively selected for data layer fusion processing with the visible original spectrum data, and the window width is 36. Further analysis is carried out using the angle conversion algorithm (refer to "A Method for Directly Determining the Components of a Multicomponent System by Raman Spectroscopy", Patent Publication No. CN106323939A, 20170111), and the results shown in Figure 10 、 Figure 11 are obtained.

[0088] After the fusion of different data segments, the correlation coefficients r between the angle values and the mass ratio of extra-virgin olive oil are 0.9871 and 0.9919 respectively, obtaining good correlation results. Therefore, the measurement spectral device of the present invention, due to the addition of the ultraviolet-visible band and the combined use of the smoothed infrared band and Raman signal band after the spectral stitching algorithm, initially provides a solid foundation for the quantitative identification of some chemical substances.

[0089] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made. These improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A spectral measurement device, characterized in that, It includes a tungsten lamp, a first coupling system, a sample holder for placing a sample, a second coupling system, a one-to-two optical fiber, an ultraviolet-visible spectrometer, a near-infrared spectrometer, and a minimum Raman system. A shutter for switching the light source is provided between the sample holder and the first coupling system; When the shutter is opened, after the tungsten lamp light passes through the first coupling system, different characteristic peaks are generated after passing through the sample on the sample holder. Through the second coupling system, the broadband light beam is split into two beams by the one-to-two optical fiber and then incident on the ultraviolet-visible spectrometer and the near-infrared spectrometer; When the tungsten lamp is blocked by the shutter, the minimum Raman system is enabled. The laser passes through the equal-focus coupling system and is incident on the sample on the sample holder, and then the Raman signal returns along the original path, passes through the equal-focus coupling system, and finally is incident on the Raman spectrometer; The minimum Raman system includes an equal-focus coupling system and a Raman spectrometer; The equal-focus coupling system includes a laser light source, a first aperture, a narrowband pass filter, a dichroic mirror, a first total reflection mirror, a second total reflection mirror, a second aperture, a third convex lens, a long-pass filter, and a fourth convex lens. When in use, the laser light source emits laser light, which is collimated by the second convex lens, passes through the first aperture and the narrowband pass filter, is reflected by the dichroic mirror, is reflected by the first total reflection mirror and the second total reflection mirror, and the light is focused on the sample center in the sample holder by the second aperture and the third convex lens to generate a Raman light beam. The Raman light beam returns to the original optical path, is collimated by the third convex lens, passes through the second total reflection mirror and the first total reflection mirror, passes through the dichroic mirror, and is focused by the fourth convex lens after passing through the long-pass filter. The focused light is incident on the Raman spectrometer after passing through the third slit.

2. The measurement spectral device according to claim 1, characterized in that, The first coupling system includes a first collimator, an optical fiber, and a second collimator arranged in sequence; the second coupling system includes a third collimator.

3. The measurement spectroscopic device according to claim 1, characterized in that, The one-to-two optical fiber is used to split a beam of light into two beams of light and includes two branched optical fibers. The cores of the two branched optical fibers are respectively arranged in a single longitudinal arrangement structure; when arranging, several cores close to the center in the non-branched optical fiber are placed in the central region of the branched optical fiber, and other cores close to the edge are placed in the edge region of the branched optical fiber.

4. The measurement spectroscopic device according to claim 1, wherein Both the second total reflection mirror and the first total reflection mirror are set at 45 degrees.

5. The measurement spectroscopic device according to claim 1, characterized in that, The output light spot of the laser light source is a vertical light spot. The focal lengths of the second convex lens, the third convex lens, and the fourth convex lens are the same. The second convex lens, the third convex lens, and the fourth convex lens jointly form an equal-focus design system for the vertical light spot with the first aperture and the second aperture. After the sample receives the laser of the equal-focus coupling system, a first converging light beam is reflected. The first converging light beam is focused by the third convex lens, the second aperture, the second total reflection mirror, the first total reflection mirror, the dichroic mirror, the long-pass filter, and the fourth convex lens of the equal-focus coupling system to form a second converging light beam. The laser light source and the first converging light beam converge to a vertical point in the sample, and the second converging light beam converges to a vertical point on the third slit conjugately.

6. The detection method of the measurement spectral device according to any one of claims 1-5, characterized in that, It includes the following steps: When the shutter is opened, after the tungsten lamp light passes through the first coupling system, different characteristic peaks are generated after passing through the sample on the sample holder. Through the second coupling system, the broadband light beam is split into two beams by the one-to-two optical fiber and then incident on the ultraviolet-visible spectrometer and the near-infrared spectrometer to reflect the ultraviolet-visible and near-infrared band information of the substance to be measured; and / or, Use a baffle to block the tungsten lamp, enable the minimum Raman system. The laser passes through the anafocal coupling system and then enters the sample on the sample stage. Then the Raman signal returns along the original path, passes through the anafocal coupling system, and finally enters the Raman spectrometer to reflect the Raman spectral information of the substance to be measured.

7. The detection method according to claim 6, wherein Perform a spectral stitching algorithm on the spectra detected by the ultraviolet-visible spectrometer and the near-infrared spectrometer to stitch the two spectra into one spectrum.

8. The detection method according to claim 7, characterized in that, The formula for the spectral stitching algorithm is: M = N1 x ( 1000 - N) / 200 + N2 x (N - 800) / 200, where N is between (800nm, 1000nm), N1 is the ordinate value of N in the ultraviolet-visible spectrometer, and N2 is the ordinate value of N in the near-infrared spectrometer.

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