Elimination method of stray peaks of silver-based surface-enhanced Raman substrate and trace detection method

Abstract

This disclosure provides a method for eliminating impurity peaks from a silver-based surface-enhanced Raman spectroscopy (SERS) substrate, comprising: placing the silver-based SERS substrate in an acetylene atmosphere and modifying the silver-based SERS substrate with the acetylene. The method includes: utilizing the reducing properties of the acetylene to reduce silver oxide on the surface of the silver-based SERS substrate; and utilizing the catalytic effect of silver to catalyze the acetylene to form a thin polyacetylene layer on the surface of the silver-based SERS substrate. This method eliminates interference from impurity peaks adsorbed on the silver substrate, improves the sensitivity of the silver-based SERS substrate, and addresses the problem of easy oxidation of nanosilver. Furthermore, the method features a simple operating process, extremely low cost, and is easily promoted and mass-produced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of Raman spectroscopy analysis, and in particular to a method for eliminating miscellaneous peaks of a silver-based surface-enhanced Raman substrate and a trace detection method. Background Art

[0002] Raman spectroscopy is a molecule-specific fingerprint spectrum with a narrow spectral band and ultra-high sensitivity, which can provide analyte information very quickly. However, the signal of ordinary Raman spectroscopy is extremely weak, which has great limitations in its application. The emergence of surface-enhanced Raman scattering (SERS) has solved the problem of weak Raman scattering. SERS is a powerful vibrational spectroscopy technology that mainly detects trace amounts of analytes by amplifying the electromagnetic field generated by local surface plasmon excitation. In this process, the surface plasmon resonance (SPR) of metal nanostructures has a great influence on SERS activity, and SPR is mainly affected by the type, size and shape of the metal. Silver has become the best SERS substrate material at present because of its excellent optical SPR properties.

[0003] Traditional SERS substrates include silver, gold, and copper. Silver is the most commonly used material for SERS substrates due to its superior Raman enhancement capabilities. However, silver's micro-nanostructures have relatively poor chemical stability in air. Furthermore, the nanostructured silver atoms are unsaturated in coordination and have high surface energy, making them susceptible to adsorption of impurity molecules from the environment. This results in the appearance of numerous difficult-to-calibrate impurity peaks on blank SERS substrates. The presence of these adsorbed impurities reduces the sensitivity of the SERS substrate. More seriously, the presence of these impurity peaks increases the difficulty of identifying and determining the fingerprint peaks of the target object, significantly interfering with the qualitative and quantitative detection of unknown objects. Summary of the Invention

[0004] In response to the problems of the existing technology, the present disclosure provides a method for eliminating impurity peaks of a silver-based surface-enhanced Raman substrate and a trace detection method, which are used to solve the technical problems in the existing technology that impurity peaks on the SERS substrate reduce the sensitivity of the SERS substrate, increase the difficulty of identifying and determining the fingerprint peaks of the target detection object, and cause serious interference with the qualitative and quantitative detection of unknown detection objects.

[0005] A first aspect of the present disclosure provides a method for eliminating stray peaks of a silver-based surface-enhanced Raman substrate, comprising: placing the silver-based surface-enhanced Raman substrate in an acetylene atmosphere; modifying the silver-based surface-enhanced Raman substrate using acetylene, including: reducing silver oxide on the surface of the silver-based surface-enhanced Raman substrate using the reducing property of acetylene; and catalyzing the acetylene to form a polyacetylene thin layer on the surface of the silver-based surface-enhanced Raman substrate using the catalytic effect of silver.

[0006] According to an embodiment of the present disclosure, placing the silver-based surface-enhanced Raman substrate in an acetylene atmosphere includes: placing the silver-based surface-enhanced Raman substrate in a vacuum drying dish; evacuating the vacuum drying dish and then introducing acetylene gas; and adjusting the amount of acetylene gas introduced to control the pressure in the vacuum drying dish.

[0007] According to an embodiment of the present disclosure, the pressure in the vacuum drying dish is controlled to be in the range of 0.08 MPa-0.1 MPa.

[0008] According to an embodiment of the present disclosure, a polyacetylene thin layer with a thickness ranging from 1 nm to 10 nm is formed on the surface of a silver-based surface-enhanced Raman spectroscopy substrate.

[0009] According to an embodiment of the present disclosure, the time range for modifying the silver-based surface-enhanced Raman substrate with acetylene is 1 min to 600 min.

[0010] A second aspect of the present disclosure provides a trace detection method, which is based on the above-mentioned elimination method and includes: placing a silver-based surface-enhanced Raman substrate in an acetylene atmosphere; modifying the silver-based surface-enhanced Raman substrate using acetylene, including: reducing silver oxide on the surface of the silver-based surface-enhanced Raman substrate using the reducing property of acetylene; and catalyzing acetylene to form a polyacetylene thin layer on the surface of the silver-based surface-enhanced Raman substrate using the catalytic effect of silver; performing Raman detection on a substance to be detected using the modified silver-based surface-enhanced Raman substrate to obtain a Raman spectrum of the substance to be detected; and performing trace analysis on the substance to be detected based on the Raman spectrum.

[0011] According to an embodiment of the present disclosure, performing Raman detection on a solution of a substance to be tested using a modified silver-based surface-enhanced Raman substrate includes: dripping a solution containing the substance to be tested onto the surface of the modified silver-based surface-enhanced Raman substrate or immersing the surface of the modified silver-based surface-enhanced Raman substrate in a solution containing the substance to be tested; and after a preset time period, using a desktop Raman spectrometer to detect the Raman spectrum of the substance to be tested.

[0012] According to an embodiment of the present disclosure, a metallic silver nanostructure is used as a substrate for a silver-based surface-enhanced Raman spectroscopy substrate.

[0013] According to an embodiment of the present disclosure, the metallic silver nanostructure includes a silver self-supporting nanocomposite structure or a nanocomposite structure with silver on its surface formed on a different substrate.

[0014] According to an embodiment of the present disclosure, the laser wavelength used in Raman detection includes one of 532 nm, 633 nm, 785 nm and 1064 nm.

[0015] The method for eliminating stray peaks of a silver-based surface-enhanced Raman substrate and the method for detecting trace amounts provided by the embodiments of the present disclosure have at least the following beneficial effects:

[0016] Acetylene is used to modify the surface of the silver-based SERS substrate. The reducing property of acetylene is used to reduce the silver oxide species on the surface of the silver-based SERS substrate, changing the adsorption state of the surface, thereby eliminating the interference of impurity peaks adsorbed on the surface of the silver-based SERS substrate, improving the sensitivity, and making it easier to recognize and identify the fingerprint peaks of the test substance, laying a material foundation for trace detection of the test substance.

[0017] Furthermore, since the silver in the silver base has a catalytic effect on acetylene, under the catalytic action of silver, acetylene is in situ polymerized on the surface of the silver-based surface enhanced Raman substrate to form a polyacetylene thin layer, which can improve the antioxidant ability of the silver-based SERS substrate, solve the problem of easy oxidation of nanosilver, thereby improving the stability of the silver-based SERS substrate during application and extending its shelf life.

[0018] In addition, this method only requires the use of acetylene gas for modification, has a simple operating process, is extremely low in cost, and is easy to promote and mass-produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The flowchart of the method for eliminating impurity peaks of a silver-based SERS substrate provided by an embodiment of the present disclosure is schematically shown.

[0020] Figure 2 The flowchart of the trace detection method provided by the embodiment of the present disclosure is schematically shown.

[0021] Figure 3 The Raman spectrum of a typical bare silver substrate adsorbed with impurities is schematically shown.

[0022] Figure 4 The Raman spectra of the acetylene-modified substrate and the bare silver substrate provided in the embodiments of the present disclosure are schematically shown.

[0023] Figure 5 The transmission electron microscope morphology images of the silver-based surface-enhanced Raman substrate and the bare silver substrate before and after modification provided by the embodiments of the present disclosure are schematically shown.

[0024] Figure 6 The Raman spectra of the bare silver substrates with different modification times provided by the embodiments of the present disclosure are schematically shown.

[0025] Figure 7 The Raman spectra of the acetylene-modified silver substrate provided in the embodiment of the present disclosure detecting methylene blue, rhodamine 6G, paraquat, and diquat are schematically shown.

[0026] Figure 8The schematic diagram shows the detection of methylene blue using a bare silver substrate and an acetylene-modified substrate provided by the embodiment of the present disclosure. As the placement time increases, the characteristic peak of methylene blue at 1622 cm -1 Variation of the normalized intensity of the Raman signal.

[0027] Figure 9 A schematic diagram shows a comparison of the Raman spectra of methylene blue detected by the impurity peak-containing substrate and the modified substrate provided in the embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the present disclosure more clearly understood, the present disclosure is further described below in conjunction with specific embodiments and with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present disclosure, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present disclosure without inventive effort are intended to fall within the scope of protection of the present disclosure.

[0029] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise," "include," etc. used herein indicate the presence of the features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0030] In this disclosure, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0031] In the description of the present disclosure, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0032] Throughout the drawings, identical elements are denoted by identical or similar reference numerals. Conventional structures or configurations are omitted where they may obscure the understanding of this disclosure. The shapes, sizes, and positional relationships of components in the drawings do not reflect actual size, proportion, or positional relationships. In addition, in the claims, any reference signs placed between parentheses should not be construed as limitations of the claims.

[0033] Similarly, in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. Descriptions with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" and the like mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in an appropriate manner.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the present disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0035] The disclosed embodiments provide a method for eliminating impurity peaks on a silver-based SERS substrate, the purpose of which is to improve the serious shortcoming of the silver-based SERS substrate being easily adsorbed by impurities, thereby introducing impurity Raman peaks that interfere with the detection of the target object. The technical principle of this elimination method is as follows: acetylene gas has reducing properties and can reduce the oxidized species adsorbed on the silver-based SERS substrate. At the same time, under the catalytic action of nanosilver, acetylene self-polymerizes into trans-polyacetylene, forming a protective film several nanometers thick on the silver substrate. While removing the impurity peaks, the stability of the SERS substrate is improved. Moreover, because the polyacetylene film is extremely thin, the sensitivity is minimally sacrificed.

[0036] The method for eliminating stray peaks of a silver-based SERS substrate provided by the embodiments of the present disclosure is described in detail below with reference to specific drawings.

[0037] Figure 1 The flowchart of the method for eliminating impurity peaks of a silver-based SERS substrate provided by an embodiment of the present disclosure is schematically shown.

[0038] like Figure 1As shown, the method may include, for example, operations S101 to S102.

[0039] In operation S101, a silver-based surface-enhanced Raman substrate is placed in an acetylene atmosphere.

[0040] In the embodiment of the present disclosure, the silver-based surface-enhanced Raman substrate can be placed in a vacuum drying dish; the vacuum drying dish is evacuated and then acetylene gas is introduced; and the pressure in the vacuum drying dish is controlled by adjusting the amount of acetylene gas introduced.

[0041] As an optional embodiment, the pressure range in the vacuum drying dish is controlled to be 0.08MPa-0.1MPa. The reason for controlling the pressure range to 0.08MPa-0.1MPa is that the vacuum drying dish is a miniature vacuum drying dish, which can only be negatively pressurized and has a certain pressure range. It should be noted that if the selected equipment can also be positively pressurized, the pressure range can be even wider. The key is to have an acetylene atmosphere. Positive or negative pressure affects the modification time, and excessive pressure may cause material failure. Therefore, within the pressure range of the equipment, while taking into account the material's ability to withstand pressure, the pressure parameters can be further optimized for different materials.

[0042] In operation S102, the silver-based surface-enhanced Raman substrate is modified using acetylene, including: reducing silver oxide on the surface of the silver-based surface-enhanced Raman substrate using the reducing property of acetylene; and catalyzing acetylene to form a polyacetylene thin layer on the surface of the silver-based surface-enhanced Raman substrate using the catalytic effect of silver.

[0043] In the embodiments of the present disclosure, the time range for modifying the silver-based surface-enhanced Raman substrate with acetylene is 1 min-600 min. The specific modification time can be determined according to the actual application scenario and is not limited by the present disclosure.

[0044] The thickness of the polyacetylene thin layer formed on the surface of the modified silver-based surface-enhanced Raman substrate is extremely thin. Preferably, the thickness of the polyacetylene thin layer is in the range of 1 nm to 10 nm.

[0045] After the modification is completed, the silver-based surface enhanced Raman substrate is stored away from light.

[0046] It should be noted that silver-based surface-enhanced Raman substrates are metallic silver nanostructures of various shapes, including but not limited to self-supporting silver or surface-silvered nanocomposite structures formed on various substrates. For example, nanorods, nanotubes, nanowires, nanoparticles, and various complex morphologies prepared by physical or chemical methods are applicable to any silver-based substrate that is prone to interference from impurity peaks.

[0047] For example, a silver-based surface-enhanced Raman substrate is placed in a vacuum drying dish and evacuated to a pressure of 0.08 MPa.

[0048] Acetylene gas was introduced into the vacuum drying dish to a pressure of 0.02 MPa, and the mixture was allowed to stand for reaction to proceed with modification.

[0049] After modification, the silver-based surface-enhanced Raman substrate was stored away from light.

[0050] Based on the same inventive concept, the present disclosure also provides a trace detection method. Figure 1 The elimination method shown is used for testing.

[0051] Figure 2 The flowchart of the trace detection method provided by the embodiment of the present disclosure is schematically shown.

[0052] like Figure 2 As shown, the method may include, for example, operations S201 to S204.

[0053] In operation S201 , a silver-based surface-enhanced Raman substrate is placed in an acetylene atmosphere.

[0054] In the embodiment of the present disclosure, a metallic silver nanostructure is used as the substrate of the silver-based surface-enhanced Raman spectroscopy substrate. The metallic silver nanostructure includes a silver self-supporting nanocomposite structure or a nanocomposite structure with silver on the surface formed on a different substrate.

[0055] In operation S202, the silver-based surface-enhanced Raman substrate is modified using acetylene, including: reducing silver oxide on the surface of the silver-based surface-enhanced Raman substrate using the reducing property of acetylene; and catalyzing acetylene to form a polyacetylene thin layer on the surface of the silver-based surface-enhanced Raman substrate using the catalytic effect of silver.

[0056] In the embodiment of the present disclosure, the Figure 1 The modification method shown is used to modify the surface of the silver-based surface-enhanced Raman substrate, which will not be described in detail here.

[0057] In operation S203 , Raman detection is performed on the substance to be detected using the modified silver-based surface-enhanced Raman substrate to obtain a Raman spectrum of the substance to be detected.

[0058] In an embodiment of the present disclosure, a solution containing the substance to be detected can be dropped onto the surface of the modified silver-based surface-enhanced Raman substrate, or the surface of the modified silver-based surface-enhanced Raman substrate can be immersed in a solution containing the substance to be detected.

[0059] In the embodiments of the present disclosure, the laser wavelength used in Raman detection includes but is not limited to one of 532 nm, 633 nm, 785 nm and 1064 nm.

[0060] In operation S204 , trace analysis is performed on the substance to be detected according to Raman spectroscopy.

[0061] In order to further verify the advantages of the silver-based surface-enhanced Raman substrate stray peak elimination method provided by the embodiments of the present disclosure, some specific examples are listed below for illustration.

[0062] Example 1:

[0063] If no special protective measures are taken after the ordinary silver-based SERS substrate is prepared, it will have obvious stray peaks during placement and storage in the air (usually after 3 hours), which will seriously affect the Raman test of subsequent samples. Therefore, the present invention adopts a modification method to remove the stray peaks.

[0064] The bare Ag substrate blank sample before modification was subjected to Raman testing using a B&W Raman microscope with the following test parameters: integration time 15s, laser power 20mW, and laser wavelength 785nm.

[0065] Figure 3 The Raman spectrum of a typical bare silver substrate adsorbed with impurities is schematically shown.

[0066] like Figure 3 As shown, at 382cm -1 , 857cm -1 , 1131cm -1 , 1404cm -1 and 1606cm -1 There are obvious miscellaneous peaks nearby, accompanied by several weaker miscellaneous peaks (such as 2139cm -1 ), the attribution of these impurity peaks is difficult to accurately determine, which may be related to the different forms of oxygen adsorbed on the silver surface. For some low-concentration substance tests, the presence of impurity peaks will interfere with the characteristic peaks of some substances to be tested, making it difficult to identify the substances.

[0067] The Ag substrate with impurity peaks was modified as follows:

[0068] For example, a silver-based surface-enhanced Raman substrate is placed in a vacuum drying dish and evacuated to a pressure of 0.08 MPa.

[0069] Acetylene gas was introduced into the vacuum drying dish to a pressure of 0.02 MPa, and the mixture was allowed to react for 4 h for modification.

[0070] The modified silver-based surface-enhanced Raman substrate was placed on a Raman spectrometer for examination. Test parameters: integration time 15s, laser power 20mW, laser wavelength 785nm.

[0071] Figure 4 The Raman spectra of the acetylene-modified substrate and the bare silver substrate provided in the embodiments of the present disclosure are schematically shown.

[0072] like Figure 4 As shown, Figure 3 The Raman spectrum shown shows the contrast of the miscellaneous peaks, the integration time is 15s, the laser power is 20mW, and the laser wavelength is 785nm.

[0073] Figure 5 The transmission electron microscope morphology images of the silver-based surface-enhanced Raman substrate and the bare silver substrate before and after modification provided by the embodiments of the present disclosure are schematically shown.

[0074] like Figure 5 As shown, there is a 1-2 nm adsorption layer on the silver surface before modification ( Figure 5 (shown in a), its crystallinity is poor and it is difficult to identify its phase. After modification, a polyacetylene coating of about 2 nm is formed ( Figure 5 This protective layer can prevent further adsorption of environmental interfering molecules, thereby effectively improving the stability of the SERS substrate and facilitating the long-term preservation of the silver SERS substrate.

[0075] Example 2:

[0076] In order to verify the optimal modification time for acetylene modification, the bare silver substrate was modified for different times under the same pressure conditions, and the process of eliminating the impurity peaks was observed to obtain the optimal modification time. The process is as follows:

[0077] Place the Ag substrate containing impurity peaks and the silver substrate into a vacuum drying dish, evacuate to a pressure of 0.08 MPa, then introduce acetylene gas into the vacuum drying dish to a pressure of 0.02 MPa, and let it stand for reaction for 1h / 2h / 3h / 4h / 5h respectively.

[0078] The detection was performed using a Zhuoli Hanguang Raman instrument. Test parameters: integration time 15s, integration times 1, laser power 40mW, laser wavelength 638nm.

[0079] Figure 6 The Raman spectra of the bare silver substrates with different modification times provided by the embodiments of the present disclosure are schematically shown.

[0080] like Figure 6 As shown in the figure, the intensity of the bare silver impurity peak decreases with increasing modification time, indicating that acetylene continuously reduces silver oxides on the surface of the nanosilver, promoting the desorption of surface impurity molecules. At a modification time of 4 hours, the impurity peak essentially disappears. Further increases in modification time lead to an increase in the thickness of the polyacetylene layer formed by the catalytic action of the nanosilver, thereby weakening the SERS performance. Therefore, the optimal modification time for this type of bare silver substrate at an acetylene gas pressure of 0.02 MPa is 4 hours.

[0081] Example 3:

[0082] To verify the Raman enhancement effect of the silver substrate after acetylene modification to remove impurity peaks, methylene blue (MB), rhodamine 6G, paraquat, and diquat were used as probe molecules for detection and evaluation. The process is as follows:

[0083] Place the Ag substrate containing impurity peaks and the silver substrate into a vacuum drying dish, evacuate to a pressure of 0.08 MPa, then introduce acetylene gas into the vacuum drying dish to a pressure of 0.02 MPa, and let it react for 4 hours.

[0084] The modified SERS substrate was immersed in methylene blue (MB), rhodamine 6G, paraquat, and diquat standard solutions with a concentration of 1 ppm (mg / L). After soaking for 5 minutes, the substrate was taken out and the surface was gently blown dry with an ear bulb. The residual solution around the substrate was absorbed with filter paper.

[0085] The detection was performed using a Zhuoli Hanguang Raman instrument. Test parameters: integration time 15s, integration times 1, laser power 40mW, laser wavelength 638nm.

[0086] Figure 7 The Raman spectra of the acetylene-modified silver substrate provided in the embodiment of the present disclosure detecting methylene blue, rhodamine 6G, paraquat, and diquat are schematically shown.

[0087] like Figure 7 As shown, the acetylene-modified substrate detects methylene blue (MB), rhodamine 6G, paraquat, and diquat, and the peaks of the corresponding Raman spectra (curves 1-4) are all characteristic peaks of the detected substances, and no interference caused by the modified background is observed.

[0088] Example 4:

[0089] In order to verify the stability of the substrate after acetylene modification and removal of impurity peaks, methylene blue (MB) was used as the probe molecule for detection and evaluation. The characteristic peak of methylene blue at 1622 cm -1 The stability of the SERS substrate is characterized by the change in the normalized intensity of the substrate. The process is as follows:

[0090] Place the Ag substrate containing impurity peaks and the silver substrate into a vacuum drying dish, evacuate to a pressure of 0.08 MPa, then introduce acetylene gas into the vacuum drying dish to a pressure of 0.02 MPa, and let it react for 4 hours.

[0091] The modified SERS substrate was immersed in methylene blue (MB) with a standard solution concentration of 1 ppm (mg / L). After soaking for 5 minutes, it was taken out and the surface was gently blown dry with an ear bulb. The residual solution around it was absorbed with filter paper.

[0092] The test was performed using a Zhuoli Hanguang Raman instrument. Test parameters: integration time 15s, integration times 1, laser power 40mW, laser wavelength 638nm

[0093] The acetylene-modified substrate and the bare silver substrate without acetylene modification were stored in air, and the above operation was repeated every 10 days.

[0094] Figure 8 The schematic diagram shows the detection of methylene blue using a bare silver substrate and an acetylene-modified substrate provided by the embodiment of the present disclosure. As the placement time increases, the characteristic peak of methylene blue at 1622 cm -1 Variation of the normalized intensity of the Raman signal.

[0095] like Figure 8 As shown, the Raman signal intensity of the substrate without acetylene modification decreases with increasing storage time. The Raman signal of the substrate modified with acetylene does not change significantly, indicating that the formed polyacetylene thin layer can effectively isolate the silver nanorods from the external environment, giving the substrate good performance stability.

[0096] Example 5:

[0097] In order to verify the Raman enhancement effect of the substrate after acetylene modification to remove impurity peaks, methylene blue (MB) was used as the probe molecule for detection and evaluation. The process is as follows:

[0098] Place the Ag substrate containing impurity peaks and the silver substrate into a vacuum drying dish, evacuate to a pressure of 0.08 MPa, then introduce acetylene gas into the vacuum drying dish to a pressure of 0.02 MPa, let it react for 4 hours, store it away from light, and take it out after 6 months.

[0099] 30 μL of 1 ppm MB standard solution was added dropwise onto the surface of a 5 mm*5 mm substrate (acetylene-modified and non-acetylene-modified). After adding the solution onto the substrate, wait for about 60 seconds and blow dry the unevaporated solution with an ear bulb.

[0100] A Zhuoli Hanguang tabletop Raman spectroscopy instrument was used for detection. Test parameters: integration time 15s, integration times 1, laser power 40mW, laser wavelength 785nm.

[0101] Figure 9 A schematic diagram shows a comparison of the Raman spectra of methylene blue detected by the impurity peak-containing substrate and the modified substrate provided in the embodiment of the present disclosure.

[0102] like Figure 9 As shown, at 499cm -1 、768cm -1 、1182cm -1 、1393cm -1 and 1622cm-1 Obvious methylene blue signals were measured at many locations. The substrate modified with acetylene has completely removed the impurity peaks (curve 4). The peaks generated after soaking in MB are all vibration peaks of different groups of MB (curve 1). In contrast, the impurity peaks of the substrate not modified with acetylene after soaking in MB still exist (curves 2 and 3). -1 The impurity peak and the MB side peak 1622cm -1 The MB peaks on the substrate containing the impurity peaks are very close and difficult to distinguish (curve 2). The MB peak intensity and peak sharpness on the substrate containing the impurity peaks are significantly lower than those on the modified substrate. It is foreseeable that the impurity peaks on the SERS substrate will seriously affect the detection of target molecules, especially for the detection of unknown molecules in complex systems. The presence of impurity peaks seriously interferes with the identification of substances, and the reduced sensitivity makes trace and ultratrace quantitative analysis difficult.

[0103] Based on the test data from the above examples, it can be seen that the method for eliminating stray peaks from silver-based surface-enhanced Raman substrates provided by the present disclosure is simple to operate, has a significant effect in eliminating stray peaks, is highly sensitive, and has a significant surface enhancement effect on silver-based surface-enhanced Raman substrates, allowing for quantitative analysis of trace substances. Furthermore, this method significantly improves the stability and durability of SERS substrates, making them highly practical. Therefore, the method for eliminating stray peaks from silver-based surface-enhanced Raman substrates offers broad application prospects in biomedicine, forensic identification, food safety, and environmental monitoring.

[0104] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A method for eliminating stray peaks in a silver-based surface-enhanced Raman spectroscopy substrate, comprising: placing the silver-based surface-enhanced Raman substrate in an acetylene atmosphere; The silver-based surface-enhanced Raman substrate is modified by using the acetylene, comprising: reducing the silver oxide on the surface of the silver-based surface-enhanced Raman substrate by using the reducing property of the acetylene; The catalytic effect of silver is used to catalyze the acetylene to form a polyacetylene thin layer on the surface of the silver-based surface enhanced Raman substrate.

2. The elimination method according to claim 1, wherein: Placing the silver-based surface-enhanced Raman substrate in an acetylene atmosphere comprises: Put the silver-based surface-enhanced Raman substrate into a vacuum drying dish; The vacuum drying dish is evacuated and then acetylene gas is introduced; The pressure in the vacuum drying dish was controlled by adjusting the amount of acetylene gas introduced.

3. The elimination method according to claim 2, wherein: The pressure in the vacuum drying dish is controlled to be in the range of 0.08 MPa-0.1 MPa.

4. The elimination method according to claim 1, wherein: A polyacetylene thin layer with a thickness ranging from 1 nm to 10 nm is formed on the surface of the silver-based surface-enhanced Raman substrate.

5. The elimination method according to claim 1, wherein: The time range of using the acetylene to modify the silver-based surface enhanced Raman substrate is 1 min to 600 min.

6. A trace detection method, the trace detection method being based on the elimination method according to any one of claims 1 to 5, comprising: placing the silver-based surface-enhanced Raman substrate in an acetylene atmosphere; The silver-based surface-enhanced Raman substrate is modified by using the acetylene, comprising: reducing silver oxide on the surface of the silver-based surface-enhanced Raman substrate by using the reducing property of the acetylene; and catalyzing the acetylene to form a polyacetylene thin layer on the surface of the silver-based surface-enhanced Raman substrate by using the catalytic effect of silver; Performing Raman detection on a substance to be tested using the modified silver-based surface-enhanced Raman substrate to obtain a Raman spectrum of the substance to be tested; The substance to be tested is subjected to trace analysis according to the Raman spectrum.

7. The trace detection method according to claim 6, wherein: The method of using the modified silver-based surface-enhanced Raman substrate to perform Raman detection on the solution of the substance to be tested includes: Dropping a solution containing the substance to be tested onto the surface of the modified silver-based surface-enhanced Raman substrate or immersing the surface of the modified silver-based surface-enhanced Raman substrate in a solution containing the substance to be tested; After a preset time period, a desktop Raman spectrometer is used to detect the Raman spectrum of the substance to be tested.

8. The trace detection method according to claim 6, wherein: A metallic silver nanostructure is used as the substrate of the silver-based surface enhanced Raman substrate.

9. The trace detection method according to claim 8, wherein: The metallic silver nanostructure includes a silver self-supporting nanocomposite structure or a nanocomposite structure formed on different substrates and containing silver on the surface.

10. The trace detection method according to claim 6, wherein: The laser wavelength used in the Raman detection includes one of 532 nm, 633 nm, 785 nm and 1064 nm.

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