Method for detecting sandalwood by surface-enhanced raman spectroscopy

Abstract

The application relates to the technical field of detection, in particular to a method for detecting sandalwood by using surface-enhanced Raman spectroscopy, which solves the problem that the existing sandalwood incense gas detection does not meet the actual use requirement, and adopts a detection equipment to detect, wherein the detection equipment comprises a combustion chamber used for igniting and continuously burning the sandalwood to be detected to form a gas to be detected; a sample cell which is connected with the combustion chamber and receives the gas to be detected, and a surface-enhanced structure is arranged in the sample cell; a laser which is used for emitting laser to the sample cell to obtain the Raman spectrum; an analysis system which is used for analyzing the gas Raman signal; and input end opening and closing valves and output end opening and closing valves are respectively arranged at the gas inlet end and the gas outlet end of the sample cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection, in particular to a method for detecting sandalwood by surface enhanced Raman spectroscopy. BACKGROUND

[0002] Incense burning is a custom in ceremonies and folk customs, among which sandalwood incense is the best incense for burning. When burned, it emits a refined and calm fragrance that penetrates the heart. Sandalwood incense, a specific product on the market, refers to a type of sandalwood product made by mixing natural sandalwood (powder or essential oil) with natural incense ingredients. Its detection standards are based on the national standards QB / T 5254-2018 Natural Plant Materials Incense - Sandalwood, GB 26386 General Technical Conditions for Incense Products, GB / T 26393 Test Method for Harmful Substances in Incense Products, and QB / T 1692.4 Health Incense.

[0003] In the prior art, a gas rapid detector based on Raman spectroscopy is disclosed in Chinese Patent No. CN 217277883 U, which includes an upper cover and a cavity. The upper cover is hingedly connected to one end of the upper surface of the cavity, and the upper surface of the cavity is provided with an air inlet hole and an air outlet hole. A non-concentric cavity reflection module and a spectrometer detection module are provided inside the cavity. The non-concentric cavity reflection module is internally provided with a gas cavity for storing the gas to be tested and a Raman spectrum excitation enhancement module for enhancing the Raman signal. The gas cavity is connected to the air inlet hole and the air outlet hole through pipelines. Electromagnetic valves are provided on the pipeline between the air inlet hole and the gas cavity, and on the pipeline between the air outlet hole and the gas cavity. Through this instrument, common gases such as oxygen, nitrogen, carbon dioxide, and ethanol can be quickly detected, and nitrogen-containing gases, olefin gases, and toxic gases that can easily pollute the environment and atmosphere can also be quickly detected.

[0004] However, in actual use, incense has different states depending on the user's environment and scene. The current detection method cannot take into account different concentrations and different fluid states of various gases. SUMMARY

[0005] Therefore, the present application provides a method for detecting sandalwood by surface enhanced Raman spectroscopy, which solves the problem of existing sandalwood incense gas detection not meeting the actual use requirements.

[0006] To achieve the above purpose, the present application is realized by the following technical solutions:

[0007] A method for detecting sandalwood by surface enhanced Raman spectroscopy, which uses a detection device for detection. The detection device includes:

[0008] a combustion chamber for igniting and continuously burning the sandalwood to be tested to form a gas to be tested;

[0009] a sample cell in communication with the combustion chamber and receiving the gas to be tested, the sample cell being provided with a surface-enhanced structure;

[0010] a laser for emitting laser light into the sample cell to obtain the Raman spectrum;

[0011] an analysis system for analyzing the gas Raman signal;

[0012] the gas inlet end and the gas outlet end of the sample cell are respectively provided with an input end on-off valve and an output end on-off valve;

[0013] the detection process comprises the following steps:

[0014] S1, flow state gas sampling detection:

[0015] S11, open the input end on-off valve and the output end on-off valve, so that the gas to be tested in the combustion chamber enters the sample cell and is continuously output from the gas outlet end;

[0016] S12, after the gas flow at the gas outlet end is stable, the laser emits laser light focused at the surface-enhanced structure to obtain the Raman spectrum;

[0017] S13, the analysis system performs flow state gas analysis to obtain a detection result R1;

[0018] S2, closed state gas sampling detection:

[0019] S21, open the input end on-off valve and close the output end on-off valve, so that the gas to be tested in the combustion chamber enters the sample cell and is continuously input;

[0020] S22, after the sample cell is filled with the gas to be tested, a fixed interval time T1 is set, the laser emits laser light focused at the surface-enhanced structure to obtain the Raman spectrum, and the analysis system sequentially performs gas analysis to obtain detection results RT1, RT2, …, RTN;

[0021] S23, draw a spectrum change curve for the obtained spectrum lines;

[0022] S3, exhaust state gas sampling detection:

[0023] S31, open the input end on-off valve and close the output end on-off valve, so that the gas to be tested in the combustion chamber enters the sample cell and is continuously input, and after the gas pressure in the sample cell is stable, close the input end on-off valve and open the output end on-off valve to exhaust naturally;

[0024] S32, set a fixed interval time T2, the laser emits laser focus at the surface enhancement structure to obtain a Raman spectrum, the analysis system sequentially performs gas analysis to obtain the test results RT11, RT12 ... ... RT1N;

[0025] S33, drawing a spectrum change curve diagram for the obtained spectrum line;

[0026] S4. Obtain data according to the above steps S1, S2, and S3 for manual analysis.

[0027] Preferably, the sample cell comprises a cavity and an incident window provided on the cavity for laser light to enter the sample cell.

[0028] Preferably, the cavity is a variable volume structure.

[0029] Preferably, the sample cell further comprises a reflective window and a reflector thereof which are arranged opposite to the incident window.

[0030] Preferably, the surface enhancement structure is composed of quartz and porous materials grown on the quartz surface.

[0031] Preferably, the analysis system includes a spectrometer for analysis, a collection lens for collecting scattered light, a filter, a coupling lens, and a concave reflector.

[0032] Preferably, the spectrometer is a CCD direct-reading spectrometer.

[0033] Preferably, the laser is an integrated transceiver laser.

[0034] By adopting the above technical solution, the beneficial effects of the present invention are:

[0035] This technical solution is aimed at daily use scenarios. In principle, it adopts the currently advanced surface-enhanced Raman spectroscopy detection method for detection, and designs detection processes under different states. According to different scenarios, the first flow state indicates that the air flow in the scene is stable, the second closed state indicates that the air in the scene is not circulating and the air pressure continues to change, and the third exhaust state indicates the continuous gas dispersion state after combustion is completed. These different scenarios are analyzed separately to obtain more complete and comprehensive analysis and detection results. From the results, we can know the gas state changes, change rate and composition changes during the combustion of the test sample. The test results are more in line with the basic requirements of the product in actual use scenarios, and are more convenient for customizing the classification and quality grade division of sandalwood incense products, setting a more detailed, accurate and practical technical specification standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the detection device according to an embodiment of the present invention.

[0037] Figure numerals: 1. combustion chamber; 2. sample pool; 2a. air inlet; 2b. air outlet; 21. input opening and closing valve; 22. output opening and closing valve; 23. incident window; 24. reflection window; 25. reflector; 3. laser; 4. analysis system; 41. spectrometer; 42. collecting lens; 43. filter; 44. coupling lens; 5. surface enhancement structure. DETAILED DESCRIPTION

[0038] The following will describe the implementation methods of the present invention in detail with reference to specific embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. Example

[0039] A method for detecting sandalwood by surface enhanced Raman spectroscopy, using a detection device for detection, referring to Figure 1 , the detection equipment includes:

[0040] Combustion chamber 1, used for igniting the sandalwood to be tested and continuously burning it to form the gas to be tested;

[0041] The sample pool 2 is connected to the combustion chamber 1 and receives the gas to be measured. The sample pool 2 is provided with a surface enhancement structure 5. The surface enhancement structure 5 is composed of quartz and a porous material grown on the quartz surface. The porous material has a large surface area, high porosity, high transmittance for visible light, a high laser damage threshold, and good gas adsorption and capture effects.

[0042] A laser 3, used for emitting laser light into the sample cell 2 to obtain the Raman spectrum;

[0043] Analysis system 4 is used for gas Raman signal analysis. It includes a spectrometer 41 for analysis, a collection lens 42 for collecting scattered light, a filter 43, and a coupling lens 44. Spectrometer 41 is a CCD direct-reading spectrometer, facilitating direct reading of relevant parameters. For details, see prior art document CN 113218930 A.

[0044] The air inlet end 2a and the air outlet end 2b of the sample pool 2 are respectively provided with an input end opening and closing valve 21 and an output end opening and closing valve 22;

[0045] The detection process includes the following steps:

[0046] S1. Flow dynamic gas sampling detection:

[0047] S11, open the input end opening and closing valve 21 and the output end opening and closing valve 22, so that the gas to be tested in the combustion chamber 1 enters the sample cell 2 and is continuously output from the gas outlet 2b;

[0048] S12, after the airflow at the air outlet 2b is stable, the laser 3 emits laser light and focuses it on the surface enhancement structure 5 to obtain a Raman spectrum;

[0049] S13, the analysis system 4 performs flow dynamic gas analysis to obtain a detection result R1;

[0050] Specifically, R1 is a spectral structure under a stable gas flow state, which can represent the basic quality of the test sample and detect whether pollutant gas is generated and the content of related gases.

[0051] S2. Closed gas sampling and testing:

[0052] S21, open the input end on-off valve 21 and close the output end on-off valve 22, so that the gas to be tested in the combustion chamber 1 enters the sample cell 2 and continues to be input;

[0053] S22, after the sample cell 2 has a gas to be measured, set a fixed interval time T1, the laser 3 emits a laser focused at the surface enhancement structure 5 to obtain a Raman spectrum, the analysis system 4 sequentially performs gas analysis to obtain the test results RT1, RT2 ... ... RTN;

[0054] S23. Draw a spectrum change curve for the obtained spectrum line; when the spectrum of RTN and RT(N-1) does not change much, the process can be terminated.

[0055] Among them, this spectral change curve can represent the internal gas composition and composition change state of the sample to be tested during the entire combustion process and after the gas concentration changes. After testing multiple samples separately, the differences between different samples can be obtained more intuitively.

[0056] S3. Exhaust gas sampling and testing:

[0057] S31, open the input end on-off valve 21 and close the output end on-off valve 22, so that the gas to be measured in the combustion chamber 1 enters the sample cell 2 and continues to be input. After the gas pressure in the sample cell 2 stabilizes, close the input end on-off valve 21 and open the output end on-off valve 22 to allow the gas to be exhausted naturally;

[0058] S32. A fixed interval T2 is set, and the laser 3 emits a laser beam focused on the surface enhancement structure 5 to obtain a Raman spectrum. The analysis system 4 sequentially performs gas analysis to obtain detection results RT11, RT12, ..., RT1N. Similarly, the process can be terminated when the spectrum of RT1N and RT1(N-1) does not change much.

[0059] S33, drawing a spectrum change curve diagram for the obtained spectrum line;

[0060] S4. Obtain data according to the above steps S1, S2, and S3 for manual analysis. This technical solution is aimed at daily use scenarios. In principle, it adopts the currently advanced surface-enhanced Raman spectroscopy detection method for detection. The detection process under different states is designed. According to different scenarios, the first flow state indicates that the air flow in the scene is stable, the second closed state indicates that the air in the scene is not circulating and the air pressure continues to change, and the third exhaust state indicates the continuous gas dispersion state after combustion is completed. These different scenarios are analyzed separately to obtain more complete and comprehensive analysis and detection results. From the results, we can know the gas state changes, change rate and composition changes during the combustion of the test sample. The test results are more in line with the basic needs of the product in actual use scenarios, and are more convenient for customizing the classification and quality grade division of sandalwood incense products, setting a more detailed, accurate and practical technical specification standard.

[0061] Structurally, the sample cell 2 includes a cavity and an incident window 23 disposed on the cavity for laser light to enter the sample cell 2. The incident window 23 is coated with a visible light anti-reflection film to ensure stable laser output. The cavity has a variable volume structure, which is a foldable organ pipe structure. This design is designed to be used when testing different samples (combustion gas volume, sample size, and other factors), allowing the equipment to meet testing needs. At the same time, the cavity size can also be adjusted as needed to more quickly obtain the desired gas concentration inside the sample cell 2.

[0062] In the actual detection process, in order to improve the identifiability of the analysis, a reflective window 24 and its reflector 25 can be installed in the sample pool 2, opposite to the incident window 23. This structure can achieve another light convergence by reflecting the laser, further enhancing the full scattering signal. In this structure, the laser 3 is an integrated transceiver laser 3.

[0063] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A method for detecting sandalwood using surface-enhanced Raman spectroscopy, characterized in that: A detection device is used for detection, and the detection device includes: A combustion chamber (1) is used to ignite the sandalwood to be tested and continuously burn it to form a gas to be tested; A sample pool (2) is connected to the combustion chamber (1) and receives the gas to be measured, and a surface enhancement structure (5) is arranged in the sample pool (2); A laser (3) for emitting laser light into the sample cell (2) to obtain the Raman spectrum; An analysis system (4) for performing gas Raman signal analysis; The air inlet (2a) and the air outlet (2b) of the sample pool (2) are respectively provided with an input end opening and closing valve (21) and an output end opening and closing valve (22); The detection process includes the following steps: S1. Flow dynamic gas sampling detection: S11, opening the input end opening and closing valve (21) and the output end opening and closing valve (22), so that the gas to be tested in the combustion chamber (1) enters the sample pool (2) and is continuously output from the gas outlet (2b); S12, after the air flow at the air outlet (2b) is stabilized, the laser (3) emits laser light and focuses it on the surface enhancement structure (5) to obtain a Raman spectrum; S13, the analysis system (4) performs flow dynamic gas analysis to obtain a detection result R1 of whether polluted gas is generated and its content; S2. Closed gas sampling and testing: S21, opening the input end opening and closing valve (21) and closing the output end opening and closing valve (22), so that the gas to be tested in the combustion chamber (1) enters the sample pool (2) and continues to be input; S22, after the sample cell (2) has the gas to be measured, a fixed interval time T1 is set, the laser (3) emits laser light and focuses it at the surface enhancement structure (5) to obtain a Raman spectrum, and the analysis system (4) sequentially performs gas analysis to obtain detection results RT1, RT2 ... RTN; S23, plotting a spectrum change curve diagram for the obtained spectrum line, wherein the spectrum change curve diagram represents the internal composition of the gas of the sample to be tested and the composition change state after the entire combustion process and the change of gas concentration; S3. Exhaust gas sampling and testing: S31, open the input end opening and closing valve (21), close the output end opening and closing valve (22), allow the gas to be measured in the combustion chamber (1) to enter the sample pool (2), and continue to input the gas. After the gas pressure in the sample pool (2) stabilizes, close the input end opening and closing valve (21), and open the output end opening and closing valve (22) to allow the gas to be exhausted naturally; S32, set a fixed interval time T2, the laser (3) emits laser light focused at the surface enhancement structure (5) to obtain a Raman spectrum, the analysis system (4) sequentially performs gas analysis to obtain the test results RT11, RT12 ... RT1N; S33, drawing a spectrum change curve diagram for the obtained spectrum line; S4. Obtain data according to the above steps S1, S2, and S3 for manual analysis.

2. The method for detecting sandalwood by surface-enhanced Raman spectroscopy according to claim 1, wherein: The sample cell (2) comprises a cavity and an incident window (23) provided on the cavity for laser light to enter the sample cell (2).

3. The method for detecting sandalwood by surface-enhanced Raman spectroscopy according to claim 2, wherein: The cavity is a variable volume structure.

4. The method for detecting sandalwood by surface-enhanced Raman spectroscopy according to claim 2, wherein: The sample cell (2) further comprises a reflection window (24) and a reflection mirror (25) disposed opposite to the incident window (23).

5. The method for detecting sandalwood by surface-enhanced Raman spectroscopy according to any one of claims 1 to 4, characterized in that: The surface enhancement structure (5) is composed of quartz and a porous material grown on the quartz surface.

6. The method for detecting sandalwood by surface-enhanced Raman spectroscopy according to any one of claims 1 to 4, characterized in that: The analysis system (4) includes a spectrometer (41) for analysis, a collection lens (42) for collecting scattered light, a filter (43) and a coupling lens (44).

7. The method for detecting sandalwood using surface-enhanced Raman spectroscopy according to claim 6, wherein: The spectrometer (41) is a CCD direct-reading spectrometer (41).

8. The method for detecting sandalwood by surface-enhanced Raman spectroscopy according to any one of claims 1 to 4, characterized in that: The laser (3) is an integrated transceiver laser (3).

Images