A raman detection system, detection method and application thereof

Abstract

The application discloses a Raman detection system, a detection method and application thereof, and the system comprises a Raman spectrometer and a fixed light shielding frame, one end of the fixed light shielding frame is fixedly connected with the Raman spectrometer, the other end is provided with an entering groove for the entering of a needle-shaped SERS probe, and an insertion groove for fixing the needle-shaped SERS probe is formed at the end of the entering groove, and the shape and size of the insertion groove are matched with the needle-shaped SERS probe. The Raman detection system has a deep color groove and a fixed light shielding device with focal length design, the groove can be used to limit the rolling of the curved surface structure of the needle-shaped SERS probe, the deep color has better light shielding effect, the distance between the instrument probe and the SERS probe can be controlled, the laser can be more accurately focused on the curved surface, the structure is small and convenient to carry, and the user operation is convenient, the application is not only an effective supplement to the SERS detection field, but also can expand the application of the SERS technology to more complex systems such as meat products and biological samples, and the application range is wider.

Description

Technical Field

[0001] This invention belongs to the field of detection technology and relates to a Raman detection system, detection method and its application, specifically a high-performance portable Raman detection system, detection method and its application. Background Technology

[0002] In recent years, Raman spectroscopy has been widely used in various fields such as food safety, pharmaceutical engineering, and customs inspection due to its convenient operation and non-invasive testing characteristics, making it the most promising point-of-care testing (POCT). However, portable Raman instruments typically have low sensitivity, making them difficult to use for trace substance detection in complex systems, thus limiting the wider application of Raman technology. Researchers have discovered that noble metals with nanoscale rough surfaces (called "SERS probes") can enhance Raman spectral signals by a million times, greatly promoting the application of portable Raman instruments in various fields. Currently, the most critical issue is how to match high-performance SERS probes with portable Raman instruments to form a high-performance portable Raman detection system.

[0003] Existing SERS probes are mostly planar substrates modified with noble metal nanoparticles. These probes generally require glass, silicon wafers, aluminum foil, etc. as substrates, and the test item is dropped onto its surface for detection. Planar substrates have many problems in actual detection: (1) they cannot obtain information inside bulk samples, such as fish, beef, and other meat products; (2) background interference signals in the test item will also be adsorbed onto the chip surface along with the target object through the dropping method, interfering with the final detection; (3) the planar substrate itself also has signals, for example, the most commonly used silicon wafers at 520 cm⁻¹. -1 There are obvious Raman peaks on both sides, which can interfere with the detection.

[0004] To address the aforementioned issues, a needle-shaped SERS probe has been developed that can be directly inserted into the interior of bulk objects for detection, and can selectively adsorb target molecules to eliminate background signal interference. However, all current fixation devices for SERS (Surface Enhanced Raman Scattering) detection processes are based on planar SERS probes. These fixation devices are typically designed according to the dimensions and height of planar SERS probes, which cannot meet the requirements for needle-shaped SERS probes. Therefore, it is necessary to develop a Raman detection system specifically for the fixation and detection process of needle-shaped SERS probes. Summary of the Invention

[0005] The present invention aims to provide a Raman detection system, detection method and its application, which is applied to the detection process of needle-shaped SERS probes and has excellent detection performance.

[0006] To achieve the above objectives, according to one aspect of the present invention, a Raman detection system is provided, the system comprising a Raman spectrometer and a fixed light-shielding frame, one end of the fixed light-shielding frame being connected and fixed to the Raman spectrometer, and the other end being provided with an entry groove for a needle-shaped surface-enhanced Raman scattering (SERS) probe to enter, the end of the entry groove being formed with a slot for fixing the needle-shaped SERS probe; the shape and size of the slot being adapted to the needle-shaped SERS probe.

[0007] According to one embodiment of the present invention, the system is a portable Raman detection system with excellent performance.

[0008] According to one embodiment of the present invention, the inlet groove is a long and narrow deep groove structure formed by cutting and extending from the side of the fixed light shield toward the center.

[0009] According to one embodiment of the invention, the slot is formed at the end of the inlet groove and extends to one side along the end.

[0010] According to one embodiment of the present invention, the slot is perpendicular to the extension direction of the inlet groove to form a U-shaped groove structure, and the slot and the inlet groove form an L-shape.

[0011] According to one embodiment of the present invention, one end of the fixed light shield is provided with a mounting hole, the shape and size of which are consistent with the probe size of the Raman spectrometer, for accommodating and fixing the probe.

[0012] According to one embodiment of the present invention, an inner measuring platform is provided in the mounting hole. The inner measuring platform extends from the periphery of the inner wall of the mounting hole toward the center and is at a certain distance from the upper port of the mounting hole. The cross-sectional dimension of the cavity below the inner measuring platform is smaller than the cross-sectional dimension of the cavity above the inner measuring platform, so as to fix the probe position in the vertical direction.

[0013] According to one embodiment of the present invention, the distance between the upper end face of the internal testing platform and the slot is L, where 1 mm ≤ L ≤ 100 mm; preferably, 3 mm ≤ L ≤ 20 mm.

[0014] According to one embodiment of the present invention, one end of the fixed light shield is formed with a pin-type fixing structure. The pin-type fixing structure has a semi-circular groove located in the middle position. Two fixing surfaces are formed by extending from the opening end to both sides along the diameter direction. The ends of the two fixing surfaces extend vertically to form two limiting blocks on both sides below the semi-circular groove. Arc-shaped clamping grooves are formed on the inner sides of the two limiting blocks respectively. The semi-circular groove and the two opposing arc-shaped clamping grooves form a cavity for accommodating the Raman spectrometer probe.

[0015] According to one embodiment of the present invention, the fixed light-shielding frame has a cylindrical structure.

[0016] According to one embodiment of the present invention, the fixed light-shielding frame is a dark plastic shell.

[0017] According to another aspect of the present invention, a detection method based on the Raman detection system is also provided, comprising the following steps:

[0018] 1) Insert the probe of the Raman spectrometer into the mounting hole or semi-circular groove of the fixed light shield;

[0019] 2) Insert the needle-shaped SERS probe into the sample to be tested;

[0020] 3) Pull out the needle-shaped SERS probe and insert it into the slot of the fixed light shield;

[0021] 4) Use a Raman spectrometer for spectral acquisition.

[0022] This invention also provides the application of the above-mentioned Raman detection system in the field of needle-shaped SERS probe detection; especially in the detection of meat products and biological samples.

[0023] The beneficial effects of this invention are:

[0024] 1) The Raman detection system of the present invention is a high-performance portable Raman detection system based on a needle-shaped SERS probe. It can be a fixed light-shielding device with grooves and focal length design for dark or black surfaces. Dark or black surfaces have better light-shielding effect. The grooves can be used to limit the rolling of the curved surface structure of the needle-shaped SERS probe and can be easily inserted into the probe. The focal length adjustment can make the laser focus on the curved surface more accurately.

[0025] 2) Current planar probes are usually large in size, and the matching detection devices are also relatively large. The matching detection device required for the needle-shaped SERS probe of this invention is more portable, which is convenient for users to operate and use. It not only effectively supplements the current SERS detection field, but also expands the application of SERS technology to the detection of more complex systems (such as meat products, biological samples, etc.), and has a wider range of applications. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a fixed light-shielding frame for fixing a needle-shaped SERS probe for detection in one embodiment of the present invention.

[0027] Figure 2 yes Figure 1 A schematic diagram of the fixed light-shielding frame used in the design.

[0028] Figure 3 yes Figure 1 The front view of the fixed sunshade used in the design.

[0029] Figure 4 This is a schematic diagram of the structure of the fixed light-shielding frame in another embodiment of the present invention.

[0030] Figure 5 yes Figure 4 Front view of the fixed sunshade frame of the medium structure.

[0031] Figure 6 This is a schematic diagram comparing the spectra of a needle-shaped SERS probe fixed with the fixed light-shielding frame of the present invention with those of a needle-shaped SERS probe fixed without a fixing device.

[0032] Figure 7 This is a schematic diagram comparing the Raman detection system of the present invention with existing gold nanorods and silver nanoparticles as SERS probes for the detection of mercaptoaniline.

[0033] Figure 8 This diagram illustrates the time comparison between the Raman detection system of this invention and commonly used Raman detection systems such as Molecular Biology, Ribotyping, ELISA, Flow Cytometry, and PCR.

[0034] Figure 9 A comparative diagram showing the signal strength of tests conducted using fixed light-shielding frames of different colors.

[0035] Reference numerals: 1. Raman spectrometer; 2. Fixed light shield; 21. Needle-shaped SERS probe; 3. Inlet groove; 4. Slot; 5. Mounting hole; 7. Pin-type fixing structure; 71. Semi-circular groove; 72. Fixing surface; 73. Limiting block; 74. Arc-shaped clamping groove. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0037] Considering that needle-shaped SERS probes differ from planar probes, their curved structure makes them prone to rolling, requiring additional design for fixation, and the detectable area of ​​needle-shaped SERS probes is more elongated and not planar, thus requiring higher focusing precision, this invention provides a Raman detection system that can be applied to the detection process of needle-shaped SERS probes.

[0038] like Figure 1-5As shown, the Raman detection system includes a Raman spectrometer 1 and a fixed light shield 2. One end of the fixed light shield 2 is connected and fixed to the probe of the Raman spectrometer 1, and the other end is provided with an entry groove 3 for inserting a needle-shaped SERS probe 21. The end of the entry groove 3 forms a slot 4 for fixing the needle-shaped SERS probe. The shape and size of the slot 4 are adapted to the shape and size of the needle-shaped SERS probe 21.

[0039] In one specific embodiment of the present invention, such as Figure 1 As shown, one end of the fixed light shield 2 is provided with a mounting hole 5 to accommodate and fix the probe of the Raman spectrometer 1. The shape and size of the cavity inside the mounting hole 5 are consistent with the probe of the Raman spectrometer 1. The size and shape of the Raman spectrometer probe inlet at the upper end of the fixed light shield 2 can be designed according to different Raman spectrometer equipment.

[0040] like Figure 1-3 As shown, the inlet groove 3 is a groove structure formed by cutting and extending from the side of the fixed light shield 2 towards the center. The end of the inlet groove 3 has an arc-shaped structure, and the slot 4 is formed at the end of the inlet groove 3 and extends to one side.

[0041] Preferably, the slot 4 is formed at the end of the inlet groove 3 and perpendicular to the extension direction of the inlet groove 3, forming a U-shaped groove structure. After the needle-shaped SERS probe 21 enters from the inlet groove 3, it is fixed in the slot 4. The size of the slot 4 is designed according to the needle-shaped SERS probe 21, and the position of the slot 4 can be designed to match the focusing distance of different Raman probes.

[0042] In use, the probe of the Raman spectrometer 1 is fixed in the mounting hole 5 of the fixed light shield 2, and then the two are connected and fixed. The needle-shaped SERS probe 21 slides into the slot 4 of the fixed light shield 2 through the inlet groove 3. During the test, the needle-shaped SERS probe 21 is perpendicular to the laser light path emitted by the Raman spectrometer and is at the optimal focal length of the laser to obtain the best signal intensity.

[0043] like Figure 3 As shown, an internal testing platform is also provided inside the mounting hole 5. The internal testing platform extends from the circumference of the inner wall of the mounting hole towards the center and is a certain distance away from the upper port of the mounting hole 5. The cross-sectional dimension of the cavity below the internal testing platform is smaller than the cross-sectional dimension of the cavity above the internal testing platform, which is used to hold the probe in the vertical direction and fix the probe position to maintain a suitable distance. The distance between the end face of the internal testing platform and the slot 4 is L, where L is the distance from the instrument probe to the SERS probe. By adjusting the distance from the instrument probe to the SERS probe, the laser can be more precisely focused on the curved surface. The above structure ensures that the fixed light shield 2 can effectively keep the light spot on the needle-shaped SERS probe during use.

[0044] By designing and adjusting the laser focal length of different Raman spectrometers 1, it can be ensured that the laser spot of the Raman device can be correctly focused on the surface of the needle-shaped SERS probe 21 to obtain the best enhanced signal. Preferably, 1 mm ≤ L ≤ 100 mm; more preferably, 3 mm ≤ L ≤ 20 mm.

[0045] In another specific embodiment of the present invention, such as Figure 4-5 As shown, a pin-type fixing structure 7 is formed at one end of the fixed light shield 2. The pin-type fixing structure 7 has a semi-circular groove 71 located in the middle position. Two fixing surfaces 72 are formed by extending from the open end to both sides along the diameter direction. The ends of the two fixing surfaces 72 extend in a direction perpendicular to the fixing surfaces and form two limiting blocks 73 on both sides below the semi-circular groove 71. Each of the two limiting blocks 73 has an arc-shaped clamping groove 74 on its two opposing inner sides. The semi-circular groove 71 and the two opposing arc-shaped clamping grooves 74 form a cavity for accommodating and fixing the probe of the Raman spectrometer 1.

[0046] Once the linear or needle-shaped SERS probe enters the slot 4, the combined action of the two limiting blocks 73 and the two fixing surfaces 72 ensures the laser position of the Raman spectrometer 1. L represents the focal length of the Raman device, which can be designed and adjusted according to the laser focal length of different Raman devices. This structure ensures that the needle-shaped SERS probe 21 in the fixed light shield 2 is correctly focused on the surface by the laser spot during the test, thereby obtaining the best signal enhancement effect.

[0047] The fixed light-shielding frame 2 is mainly used to fix and control the position of the needle-shaped SERS probe, facilitating focusing and detection by the Raman spectrometer. Using the fixed light-shielding frame 2 significantly enhances the SERS spectrum (see...). Figure 6 ).

[0048] When applied to needle-shaped SERS probe detection processes, the Raman detection system of this invention exhibits superior detection performance compared to currently available detection systems based on planar probes. A comparison was made between the Raman detection system of this invention and commonly used gold nanorods and silver nanoparticles as SERS probes for the commonly detected substance mercaptoaniline. Figure 7 As can be seen, compared with common Raman detection systems using gold nanorods and silver nanoparticles as SERS probes, the Raman detection system of this invention has a more obvious signal, and the detection limit for mercaptoaniline can reach 10. -8 M is 1-3 orders of magnitude higher than the previous system.

[0049] The Raman detection system of this invention features a unique light-shielding frame structure capable of fixing a needle-shaped SERS probe. It can be used for signal detection inside fish and various meat products, thereby eliminating the need for pretreatment and reducing detection time from over ten minutes to less than three minutes. Figure 8 As shown, commonly used methods such as molecular biology, ribotyping, ELISA, flow cytometry, and PCR require several hours, while the Raman detection system of this invention only takes 6 minutes.

[0050] The present invention does not impose any special restrictions on the shape of the fixed light-shielding frame 2, as long as it meets the requirements. Preferably, the fixed light-shielding frame 2 is cylindrical. The fixed light-shielding frame 2 can be manufactured by injection molding or by 3D printing additive manufacturing.

[0051] In addition to securing the needle-shaped SERS probe, the fixed light-shielding bracket 2 also serves to block light and eliminate the influence of ambient light on the detection. Preferably, the fixed light-shielding bracket 2 has a dark-colored plastic housing. Figure 9 As can be seen, the different colors of the fixed light shielding frame have different effects on blocking ambient light. Dark colors have a better effect on blocking ambient light, and dark materials can improve the light shielding effect, especially black, which has the best effect on blocking ambient light and is more conducive to enhancing Raman signals.

[0052] The present invention also provides a Raman detection method for needle-shaped SERS probes, wherein the method employs the above-described Raman detection system.

[0053] According to one embodiment of the present invention, the method specifically includes the following steps:

[0054] 1) Insert the probe of the Raman spectrometer into the mounting hole or semi-circular groove of the fixed light shield;

[0055] 2) Insert the needle-shaped SERS probe into the sample to be tested;

[0056] 3) Pull out the needle-shaped SERS probe and insert it into the slot of the fixed light shield;

[0057] 4) Use a Raman spectrometer for spectral acquisition.

[0058] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0059] Example 1

[0060] 1) Figure 2-3 The fixed light shield shown in the structure is fixed on the Raman spectrometer. The specific operation is as follows: insert the front probe of the Raman spectrometer into the mounting hole of the fixed light shield.

[0061] 2) Insert the needle-shaped SERS probe into the aquatic product and leave it for 3 minutes before removing it;

[0062] 3) Place the SERS probe in the fixed light shield and use slot 4 to fix the position of the needle-shaped SERS probe in the vertical direction of the Raman spectrometer (i.e., fix the focusing distance of the laser), while keeping the horizontal distance movable (to facilitate the acquisition of spectral signals from different points on the needle-shaped SERS probe).

[0063] 4) Use a Raman spectrometer to collect spectra, thereby obtaining data information about aquatic products.

[0064] Example 2

[0065] 1) Adopt Figure 4-5 The pin-type fixing structure shown in the diagram is used to fix the light shield on the Raman spectrometer. The specific operation is as follows: insert the handheld front probe into the corresponding semi-circular groove of the fixing light shield. The two fixing surfaces and two arc-shaped clamping grooves are used to fix the probe position and maintain a suitable distance.

[0066] 2) Insert the needle-shaped SERS probe into the meat product, leave it for 3 minutes, and then remove it;

[0067] 3) Place the needle-shaped SERS probe in the fixed light-shielding frame and use the slot to fix the position of the needle-shaped SERS probe in the vertical direction of the Raman spectrometer (i.e., fix the focusing distance of the laser), while keeping the horizontal distance movable (to facilitate the acquisition of spectral signals from different points on the probe).

[0068] 4) Use a handheld Raman spectrometer to collect spectra and obtain data information about aquatic products.

[0069] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Raman detection system, characterized in that, The system includes a Raman spectrometer (1) and a fixed light shield (2). One end of the fixed light shield (2) is connected and fixed to the Raman spectrometer (1), and the other end is provided with an entry groove (3) for the needle-shaped SERS probe (21) to enter. The end of the entry groove (3) forms a slot (4) for placing and fixing the needle-shaped SERS probe (21). The shape and size of the slot (4) are adapted to the needle-shaped SERS probe (21).

2. The Raman detection system as described in claim 1, characterized in that, The inlet groove (3) is a long and narrow groove structure formed by cutting and extending from the side of the fixed light shield (2) towards the center.

3. The Raman detection system as described in claim 1, characterized in that, The slot (4) is formed at the end of the inlet slot (3) and extends to one side along the end.

4. The Raman detection system as described in claim 3, characterized in that, The slot (4) extends perpendicularly to the inlet groove (3) to form a U-shaped groove structure, and the slot (4) and the inlet groove (3) form an L-shape.

5. The Raman detection system as described in claim 1, characterized in that, The fixed light shield (2) has a mounting hole (5) at one end. The shape and size of the mounting hole (5) are consistent with the probe size of the Raman spectrometer (1) and are used to accommodate and fix the probe.

6. The Raman detection system as described in claim 5, characterized in that, An internal testing platform is provided inside the mounting hole (5). The internal testing platform extends from the circumference of the inner wall of the mounting hole (5) toward the center and is a certain distance away from the upper port of the mounting hole (5). The cross-sectional dimension of the cavity below the internal testing platform is smaller than that of the cavity above the internal testing platform, so as to fix the probe position in the vertical direction.

7. The Raman detection system as described in claim 6, characterized in that, The distance between the upper surface of the internal testing platform and the slot (4) is L, where 1 mm ≤ L ≤ 100 mm.

8. The Raman detection system as described in claim 1, characterized in that, One end of the fixed light shield (2) has a pin-type fixing structure (7). The pin-type fixing structure (7) has a semi-circular groove (71) located in the middle. Two fixing surfaces (72) are formed by extending from the opening end to both sides along the diameter direction. The ends of the two fixing surfaces (72) extend vertically to form two limiting blocks (73) on both sides below the semi-circular groove (71). Arc-shaped clamping grooves (74) are formed on the inner sides of the two limiting blocks (73) respectively. The semi-circular groove (71) and the two opposing arc-shaped clamping grooves (74) form a cavity for accommodating the probe of the Raman spectrometer (1).

9. A detection method based on the Raman detection system according to any one of claims 1 to 8, characterized in that, The method includes the following steps: 1) Insert the probe of the Raman spectrometer into the mounting hole or semi-circular groove of the fixed light shield; 2) Insert the needle-shaped SERS probe into the sample to be tested; 3) Pull out the needle-shaped SERS probe and insert it into the slot of the fixed light shield; 4) Use a Raman spectrometer for spectral acquisition.

10. The application of the Raman detection system according to any one of claims 1 to 8 in the field of needle-shaped SERS probe detection.

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