Detection device

Abstract

A detection device 10 comprises a vibrating body, a vibration-exciting part for vibrating the vibrating body, a vibration detection part for detecting vibration of the vibrating body, a sensing part 16 that adsorbs gas molecules, and a support part 15 that is provided on the vibrating body and supports the sensing part 16. The support part 15 has protrusions and recesses on a face in contact with the sensing part 16, and supports the sensing part 16 at the protruding portions.

Description

Detection device

[0001] This disclosure relates to a detection device for detecting gases.

[0002] Surface acoustic wave (SWA) sensors are used to measure the composition and concentration of gases. SWA sensors utilize the fact that the speed and attenuation of surface acoustic waves propagating along the surface of a piezoelectric crystal change due to physical and chemical changes in the medium in contact with the propagation surface, thereby measuring the composition and concentration of the surrounding gas. A sensitive film that adsorbs and desorbs gas molecules is formed on the propagation surface of the surface acoustic waves. Generally, polymer materials are used as the sensitive film.

[0003] "Real-time detection of acetone gas molecules at ppt levels in an air atmosphere using a partially suspended graphene surface acoustic wave skin gas sensor", Haolong Zhou, Sankar Ganesh Ramaraj, Kaijie Ma, Md Shamim Sarker, Zhiqiang Liao, Siyi Tang, Hiroyasu Yamahara and Hitoshi Tabata, Nanoscale Adv., 2023,5, 6999-7008

[0004] The detection sensitivity (gas concentration) of conventional surface acoustic wave sensors is ppm (10 －６ ) However, in order to apply this to health monitoring and disease diagnosis by measuring biological gases (such as exhaled gas and skin gases), ppt(10 －１２ ) ~ ppb (10 －９ High-sensitivity (low-concentration) gas detection is required.

[0005] This disclosure is made in view of these challenges, and its purpose is to improve the sensitivity of the detection device.

[0006] To solve the above problems, a detection device according to one aspect of the present invention comprises a vibrating body, an excitation unit for vibrating the vibrating body, a vibration detection unit for detecting the vibration of the vibrating body, a sensing unit for adsorbing gas molecules, and a support unit provided on the vibrating body and supporting the sensing unit, wherein the support unit has irregularities on the surface in contact with the sensing unit, and the sensing unit is supported by the convex portion.

[0007] According to this disclosure, the sensitivity of the detection device can be improved.

[0008] This figure shows the configuration of a detection device according to the first embodiment of this disclosure. This figure shows the Young's modulus and elastic wave propagation speed of various materials. LiTaO ３ This figure shows the simulation results of the propagation speed of surface acoustic waves when a propagation section composed of various materials is formed on the substrate. This figure shows the relationship between the simulation results of the propagation speed of surface acoustic waves and Young's modulus. This figure shows an example of the configuration of the support section. This figure shows the relationship between the distance between the centers of the pillars and the center frequency of the surface acoustic wave. This figure shows the relationship between the height of the pillars and the center frequency of the surface acoustic wave. This figure shows the relationship between the concentration of acetone contained in the gas to be analyzed and the frequency change of the surface acoustic wave. This figure shows the time change of the frequency measured by the detection device of the example and comparative example. This figure shows the response time and recovery time in the detection device of the example and comparative example. This figure shows the configuration of the detection device according to the second embodiment of this disclosure. This is a schematic cross-sectional view of the detection device according to the second embodiment of this disclosure. This is a perspective view of the detection device used in the simulation. This figure shows the simulation results of the pillar height dependence of the resonance frequency when no sensing section is provided. This figure shows the simulation results of the pillar height dependence of the resonance frequency when a sensing section is provided. This figure shows the pillar height dependence of the resonance amplitude obtained from the simulation results of Figure 15. This figure shows the frequency shift of the vibration of the vibrating body when gas is introduced into a detection device without a support section.

[0009] The detection device of this disclosure comprises a vibrating body, an excitation unit for causing the vibration, a vibration detection unit for detecting the vibration of the vibrating body, a sensing unit for adsorbing gas molecules, and a support unit provided on the vibrating body for supporting the sensing unit. When gas molecules to be detected are adsorbed onto the sensing unit, the elasticity and mass of the sensing unit change, and this change affects the vibration of the vibrating body via the support unit. Therefore, gas can be detected from the change in the vibration of the vibrating body. If the detection device is configured so that the natural frequencies of the mechanical vibration of the sensing unit and the acoustic vibration of the support unit match, the vibration is amplified by coupled resonance, so that even slight changes in the elasticity and mass of the sensing unit caused by the adsorption of a very small amount of gas molecules onto the sensing unit can be amplified and detected.

[0010] The vibrating body may include a piezoelectric element that deforms in response to the application of voltage. In this case, the excitation unit may include an input electrode for applying voltage to the piezoelectric element, and the vibration detection unit may include an output electrode that converts the vibration of the piezoelectric element into an electrical signal. The excitation unit may mechanically excite the vibrating body.

[0011] The detection device of this disclosure may detect surface acoustic waves such as Love waves, Rayleigh waves, and shear horizontal surface acoustic waves (SH-SAW) propagating on the surface of a vibrating body, or it may detect waveguide acoustic waves such as shear horizontal acoustic plate mode (SH-APM), flexural plate wage (FPW), and Lamb waves, or it may detect bulk acoustic waves such as thickness shear mode propagating inside a vibrating body.

[0012] First, as a first embodiment, a detection device for detecting surface acoustic waves, particularly Love waves, propagating along the surface of a piezoelectric substrate will be described. Next, as a second embodiment, a detection device for detecting thickness-sliding vibrations propagating inside a piezoelectric material will be described.

[0013] (First Embodiment) FIG. 1 shows the configuration of a detection device 10 according to the first embodiment of the present disclosure. The detection device 10 includes a substrate 11, an input electrode 12, an output electrode 13, a propagation unit 14, a support unit 15, and a sensitive unit 16.

[0014] The substrate 11 is an example of a vibrating body and is formed of a piezoelectric body that deforms in response to the application of a voltage. The substrate 11 is made of lithium tantalate (LiTaO ３ ), lithium niobate (LiNbO ３ ), quartz (SiO ２ ), zinc oxide (ZnO), aluminum nitride (AlN), scandium-added aluminum nitride (Sc:AlN), or the like.

[0015] The input electrode 12 applies a voltage for exciting a surface acoustic wave to the substrate 11 on the surface of the substrate 11. The output electrode 13 converts the surface acoustic wave generated on the surface of the substrate 11 by the voltage applied from the input electrode 12 into an electrical signal and outputs it. The input electrode 12 and the output electrode 13 have a comb (bar-shaped) shape. A surface acoustic wave having a wavelength corresponding to the interval between the combs of the input electrode 12 is generated. The input electrode 12 and the output electrode 13 may be formed of a metal such as chromium (Cr) or gold (Au), a conductive oxide such as strontium ruthenate (SrRuO ３ ), lanthanum cobaltate (LaCoO ３ ), or a conductive nitride such as TiN. The input electrode 12 and the output electrode 13 may be formed using a technique such as laser beam lithography.

[0016] The propagation unit 14 is provided between the input electrode 12 and the output electrode 13 on the surface of the substrate 11 and propagates the surface acoustic wave generated on the surface of the substrate 11 by the voltage applied from the input electrode 12. The propagation unit 14 may be formed of SiO ２ 、TiO ２ 、Al ２ O ３ 、ZnO, PMMA, Au, or the like. The propagation unit 14 may be formed using any known film formation technique such as sputtering.

[0017] The sensing element 16 adsorbs the gas molecules to be detected. The sensing element 16 is composed of graphene, graphene oxide (GOx), reduced graphene oxide (rGOx), transition metal carbides, transition metal nitrides, boron nitride (BN), and magnesium boride (MgB). ２ ), transition metal dichalcogenite (MX ２ The sensing part 16 may be formed from a material having a layered structure (X = S, Se, Te, etc.). The sensing part 16 may be formed from a single layer or several layers of material. The sensing part 16 may be formed from a material capable of selectively adsorbing the gas molecules to be detected. The surface of the sensing part 16 may be chemically modified, such as by introducing functional groups, so that the target gas molecules can be adsorbed.

[0018] The support portion 15 is provided on the propagation portion 14 and supports the sensing portion 16. The support portion 15 has an uneven structure on the surface that contacts the sensing portion 16, and the convex portion supports the sensing portion 16. The support portion 15 may have a plurality of pillars, and the pillars may support the sensing portion 16. The support portion 15 may be formed from the same material as the propagation portion 14. The support portion 15 may be formed using a technique such as laser beam lithography.

[0019] When the gas to be analyzed, including the gas to be detected, is introduced near the sensing unit 16 of the detection device 10, the elasticity and mass of the sensing unit 16 change when gas molecules of the target gas are adsorbed onto the sensing unit 16. This change affects the surface acoustic waves propagating through the propagation unit 14 via the support unit 15. Therefore, by comparing the electrical signal output from the output electrode 13 with the electrical signal output from the output electrode 13 when no gas molecules are adsorbed onto the sensing unit 16, the presence or absence and concentration of the target gas molecules can be detected.

[0020] The change in the frequency of surface acoustic waves is expressed by the following equation. The first term represents the elastic effect, the second term represents the mass effect, and the third term represents the electroacoustic effect. The larger the elastic modulus (Young's modulus) E of the sensing part 16, the greater the change in the frequency of the surface acoustic wave when gas molecules are adsorbed on the sensing part 16, due to the contribution of the elastic effect in the first term, thus improving the sensitivity of the detection device 10. Therefore, it is preferable that the sensing part 16 be formed from a material with a high elastic modulus. The elastic modulus of the sensing part 16 may be, for example, 10 GPa or more, 50 GPa or more, 100 GPa or more, 200 GPa or more, 300 GPa or more, 400 GPa or more, 500 GPa or more, 600 GPa or more, 700 GPa or more, 800 GPa or more, 900 GPa or more, or 1000 GPa or more. In particular, graphene has a high elastic modulus of 1 TPa and is suitable as a material for forming the sensing part 16.

[0021] Figure 2 shows the Young's modulus and elastic wave propagation velocity of various materials that can constitute the substrate 11, propagation section 14, and support section 15. The materials constituting the substrate 11, propagation section 14, and support section 15 may be selected considering these physical properties and the above-mentioned conditions.

[0022] Figure 3 shows LiTaO ３ The simulation results of the propagation speed of surface acoustic waves when a propagation section 14 made of various materials is formed on the substrate 11 are shown. Figure 4 shows the relationship between the simulation results of the propagation speed of surface acoustic waves and Young's modulus.

[0023] The propagation section 14 may be formed of a material or thickness such that the propagation speed of surface acoustic waves is slower than that of the piezoelectric material constituting the substrate 11. As a result, the mode of the surface acoustic wave becomes a Love wave, in which the wave energy is concentrated and propagates in the propagation section 14, which can greatly increase the change in the elastic effect caused by the adsorption of the gas molecules to be detected onto the sensing section 16, and thus improve the sensitivity of the detection device 10. For example, 36YX-LiTaO ３ When the substrate 11 is formed by this, the propagation section 14 has a surface acoustic wave propagation velocity of 36°YX-LiTaO ３ It may be formed to be slower than the propagation speed of the Love wave in 36YX-LiTaO ３When the substrate 11 is formed by SiO, as shown in Figure 3, ２ This material is suitable for forming the propagation section 14.

[0024] The propagation section 14 may be formed of a material or thickness such that the propagation speed of surface acoustic waves is faster than that of the piezoelectric material constituting the substrate 11. As shown in Figure 3, tungsten or silicon nitride (SiN ｘ (1 < x < 2) or Si ３ N ４ Materials like the one described above generally have a faster surface acoustic wave propagation speed than the material constituting the substrate 11. In this case, the surface acoustic waves are trapped at the interface, forming guide modes or leaking modes. This can increase signal sensitivity or adjust the frequency response.

[0025] Figure 5 shows an example of the configuration of the support section 15. Figure 5 is a top view and a side view of the support section 15. The support section 15 includes a plurality of pillars 17 arranged periodically. The surface of the support section 15 that is in contact with the sensing section 16 has an uneven structure including protrusions where the pillars 17 are provided and recesses where the pillars 17 are not provided, and the sensing section 16 is supported by the pillars 17 which are the protrusions.

[0026] When the mechanical vibrations of the sensing element 16 and the acoustic vibrations of the pillar 17 coincide, they resonate and form a hybrid resonance mode. This coupled resonance further amplifies the displacement and energy of the Love wave on the surface of the propagation element 14. As a result, even slight changes in the elasticity and mass of the sensing element 16 caused by the adsorption of a very small amount of gas molecules onto the sensing element 16 are amplified and can be detected, thereby improving the sensitivity of the detection device 10.

[0027] The center-to-center distance i between adjacent pillars 17 may be 1 / 4 of the wavelength λ of the surface acoustic wave excited by the input electrode 12. Thereby, since the support portion 15 and the sensitive portion 16 can be resonated with the surface acoustic wave propagating through the propagation portion 14, the sensitivity to the change in the elastic effect due to the adsorption of gas molecules on the sensitive portion 16 can be improved. The center-to-center distance i of the pillars 17 does not necessarily have to be exactly equal to 1 / 4 of the wavelength λ of the surface acoustic wave. The difference between the center-to-center distance i of the pillars 17 and 1 / 4 of the wavelength λ of the surface acoustic wave may be 20% or less, 15% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less of λ.

[0028] The shape of the pillar 17 may be any shape such as a cylinder, triangular prism, quadrangular prism, polygonal prism, cone, triangular pyramid, quadrangular pyramid, polygonal pyramid, frustum of a cone, frustum of a triangular pyramid, frustum of a quadrangular pyramid, frustum of a polygonal pyramid, etc. The number of pillars 17 may be one or two or more. The height h and diameter d of the pillar 17 may be adjusted so that the natural frequencies of the mechanical vibration of the sensitive portion 16 and the acoustic vibration of the pillar 17 coincide to introduce coupled resonance. The larger the diameter d of the pillar 17, the smoother the top surface of the pillar 17 can be formed, so the adhesiveness with the sensitive portion 16 becomes good, and the sensitivity of the detection device 10 can be improved. Also, the larger the height h of the pillar 17, the more the gas flow in the space between the pillars 17 is promoted, so the response speed can be improved.

[0029] In the example of FIG. 5, a plurality of pillars 17 are distributed in a lattice pattern, but the plurality of pillars 17 may be arranged in any distribution. In the example of FIG. 5, the pillar 17, which is a convex portion, is provided on the propagation portion 14, but a plurality of concave portions may be provided in the layer provided on the propagation portion 14. In this case, the position where the concave portion is not provided supports the sensitive portion 16 as a convex portion. In the example of FIG. 5, the sensitive portion 16 is supported so as to be substantially parallel to the substrate 11 and the propagation portion 14, but the sensitive portion 16 may be supported so as to be inclined with respect to the substrate 11 or the propagation portion 14.

[0030] The detection device 10 may include a separation unit for separating a specific type of gas from the gas to be analyzed. The separation unit may include a molecular sieve composed of a porous material such as zeolite. Thereby, the accuracy of the detection device 10 can be improved.

[0031] (Example) The detection device 10 according to the embodiment was fabricated, and a gas to be analyzed containing acetone gas was introduced to detect the acetone gas. As a comparative example, a detection device without the pillar 17 was fabricated and the same experiment was conducted.

[0032] (Fabrication of electrodes) On a 36°YX - LiTaO ３ substrate, 60 sets of comb-shaped electrode (IDT) patterns were designed at an interval of 32 μm using laser beam lithography. Cr / Au with a thickness of 80 nm was deposited and lift-off was performed.

[0033] (Fabrication of micropillars) The LT substrate was cleaned by a standard chemical process, and a SiO ２ layer was deposited by magnetron sputtering technology. Micropillars were designed by laser beam lithography using a positive resist, and resist development and oxygen plasma etching were performed.

[0034] (Transfer of graphene) Commercially available CVD graphene was transferred onto the pillars. Polymethyl methacrylate (PMMA) was spin-coated onto the copper / graphene substrate and heated at 150 °C for 2 minutes. Further, the copper foil was etched with oxygen plasma and a 0.1 M ammonium persulfate solution. The graphene was transferred onto the micropillars. The substrate was immersed in acetone at 60 °C to remove the PMMA on the graphene surface.

[0035] (Measurement) The gas to be analyzed was introduced into the fabricated detection devices of the example and the comparative example, and the vibration frequency of the response signal output from the output electrode 13 was recorded using a network analyzer (PNA - N5222B). The response signal output from the output electrode 13 of the detection device 10 is defined as Δf = f ｓ - f ０ Here, f ｓ is the vibration frequency of the surface acoustic wave when exposed to the gas to be analyzed, and f ０This represents the center frequency of surface acoustic waves in the surrounding environment. After the measurement, nitrogen gas molecules were purged into the chamber to restore the device to its original state.

[0036] (Distance between pillar centers and center frequency of surface acoustic waves) Figure 6 shows the relationship between the distance between pillar centers and the center frequency of surface acoustic waves. In the detection device 10 of the embodiment, surface acoustic waves with a wavelength λ of 32 μm are generated. It was shown that the center frequency is maximum and the sensitivity for detecting frequency changes is maximum when the distance between pillar centers is 8 μm, which is 1 / 4 of λ.

[0037] (Pillar height and center frequency of surface acoustic waves) Figure 7 shows the relationship between pillar height and center frequency of surface acoustic waves. It was shown that the center frequency is maximum when the pillar height is 1000 nm, and the sensitivity for detecting frequency changes is maximum.

[0038] (Acetone concentration and frequency change) Figure 8 shows the relationship between the concentration of acetone in the gas being analyzed and the frequency change of surface acoustic waves. It was shown that even when the acetone concentration is 1 ppb, the detection device 10 of the example can detect the frequency change of surface acoustic waves.

[0039] (Acetone concentration and response speed) Figure 9 shows the time variation of the frequency measured by the detection devices of the example and comparative example. Figure 10 shows the response time and recovery time of the detection devices of the example and comparative example. The detection device 10 of the example was shown to have a faster response speed and recovery speed than the detection device of the comparative example.

[0040] Acetone is known as a marker for diabetes and lipid metabolism. The detection device 10 of this disclosure can detect acetone gas at low concentrations of 1 ppb or less released from the skin, enabling non-invasive, continuous monitoring without requiring conscious action from the user. This is expected to have applications in early disease detection, health monitoring, remote diagnosis, and exercise management.

[0041] Furthermore, it is believed that this technology can be extended to the detection of other bio-related gases and volatile organic compounds (VOCs) besides acetone, and the realization of an electronic nose (eNose) is also anticipated. For example, hydrogen and methane are associated with abnormalities in intestinal anaerobic bacteria, ethanol with alcohol consumption, hydrogen peroxide and carbon monoxide with smoking, isoprene is an intermediate in cholesterol synthesis, acetaldehyde and nonanal with lung cancer, nitric oxide with asthma and respiratory infections, hydrogen sulfide with periodontitis, methyl mercaptan with liver disease and colorectal cancer, ammonia with hepatitis and Helicobacter pylori infection, and trimethylamine with renal failure and chronic kidney disease. Therefore, by detecting these gases, it is expected that it can be used for early disease detection, monitoring of health status, remote diagnosis, and exercise management.

[0042] (Second Embodiment) Figure 11 shows the configuration of a detection device 20 according to a second embodiment of the present disclosure. Figure 12 is a schematic cross-sectional view of the detection device 20 according to a second embodiment of the present disclosure. The detection device 20 comprises a vibrating body 21, electrodes 22, electrodes 23, a support part 25, and a sensing part 26.

[0043] The vibrating body 21 is a piezoelectric material formed in the shape of a plate. The vibrating body 21 may also be a thin plate-shaped section of a crystal such as quartz. The vibrating body 21 may be made of lead zirconate titanate (PZT), langasite (La ３ Ga ５ SiO １４ ), gallium orthophosphate (GaPO ４ ) or the like may be formed.

[0044] A pair of electrodes 22 and 23 are provided on the upper and lower surfaces of the vibrating body 21, sandwiching the vibrating body 21. A voltage applied between electrodes 22 and 23 causes thickness-sliding vibration in the vibrating body 21, and the electrical response resulting from this vibration is output.

[0045] The sensing unit 26 adsorbs the gas molecules to be detected. The sensing unit 26 may be the same as the sensing unit 16 in the first embodiment.

[0046] The support portion 25 is provided on the vibrating body 21 and supports the sensing portion 26. The support portion 25 may be the same as the support portion 15 in the first embodiment.

[0047] Figure 13 is a perspective view of the detection device 20 used in the simulation. The vibrating body 21 is a 100 μm thick disc made of lead zirconate titanate. The electrodes 22 and 23 are 4 μm thick discs made of quartz. The support section 25 consists of 50 x 50 pillars made of quartz, each with a diameter of 4 μm, arranged at 4 μm intervals in a 400 μm x 400 μm area. The sensing section 26 is a graphene formed in a 400 μm x 400 μm square.

[0048] Figure 14 shows the simulation results of the pillar height dependence of the resonant frequency when the sensing element 26 is not provided. (a) shows the relationship between amplitude (nm) and frequency (MHz) when there is no pillar (0 μm), (b) shows 4 μm, (c) shows 8 μm, and (d) shows 12 μm. The arrows in the figure indicate the resonant frequency. Under the conditions of this simulation, the strongest resonance was observed when the pillar height was 8 μm.

[0049] Figure 15 shows the simulation results of the pillar height dependence of the resonant frequency when the sensing element 26 is provided. (a) shows the relationship between amplitude (nm) and frequency (MHz) for 1 μm, (b) for 2 μm, (c) for 4 μm, and (d) for 8 μm. The arrows in the figure indicate the resonant frequency. Figure 16 shows the pillar height dependence of the resonant amplitude obtained from the simulation results of Figure 15. Under the conditions of this simulation, the strongest resonance was observed when the pillar height was 2 μm. Therefore, by providing a pillar with a diameter of 4 μm and a height of 2 μm as the support element 25, gas can be detected with higher accuracy.

[0050] The diameter, height, spacing, number, distribution density, and shape of the pillars constituting the support section 25 may be adjusted according to the type, shape, thickness, and vibration mode of the vibrating body 21, the type, shape, thickness, and weight of the sensing section 26, the type, quantity, and concentration of the gas to be detected, and the voltage and frequency applied to the vibrating body 21.

[0051] Figure 17 shows the frequency shift of the vibration of the vibrating body 21 when a gas is introduced into the detection device 20 without the support part 25. (a) shows the experimental results when the sensing part 26 is not provided, and (b) shows the experimental results when the sensing part 26 is provided. When the sensing part 26 is not provided, no frequency shift was observed even when 1000 ppm acetone and 1000 ppm ammonia were introduced, but when the sensing part 26 was provided, a frequency shift was observed when 1000 ppm acetone and 1000 ppm ammonia were introduced. Similarly, it is thought that a frequency shift will be observed when acetone or ammonia is introduced even when the support part 25 is provided. Thus, it has been shown that the detection device 20 of the second embodiment can detect trace amounts of gas.

[0052] The present disclosure has been explained above based on examples. These examples are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications are also within the scope of the present disclosure.

[0053] This invention can be used in detection devices for detecting gases.

[0054] 10...Detection device, 11...Substrate, 12...Input electrode, 13...Output electrode, 14...Propagation part, 15...Support part, 16...Sensing part, 17...Pillar, 20...Detection device, 21...Vibrating body, 22...Electrode, 23...Electrode, 25...Support part, 26...Sensing part.

Claims

1. A detection device comprising: a vibrating body; an excitation unit for vibrating the vibrating body; a vibration detection unit for detecting the vibration of the vibrating body; a sensing unit for adsorbing gas molecules; and a support unit provided on the vibrating body for supporting the sensing unit, wherein the support unit has irregularities on the surface in contact with the sensing unit, and the convex portion supports the sensing unit.

2. The detection device according to claim 1, wherein the vibrating body includes a piezoelectric body, the excitation unit includes electrodes for applying a voltage to the piezoelectric body, and the vibration detection unit includes electrodes for converting the vibration of the vibrating body into an electrical signal.

3. The detection device according to claim 1, wherein the sensing part has a sheet-like structure.

4. The detection device according to claim 3, wherein the sensing part comprises graphene, graphene oxide, reduced graphene oxide, transition metal carbide, transition metal nitride, or transition metal dichalcogenide.

5. The detection device according to any one of claims 1 to 4, wherein the support portion includes a plurality of pillars.

6. The detection device according to claim 5, wherein the distance between the centers of the plurality of pillars is 1 / 4 of the wavelength of the elastic wave generated on the surface of the vibrating body.

7. The detection device according to any one of claims 1 to 4, comprising a separation unit for separating a specific type of gas from a gas to be analyzed.

8. The detection device according to any one of claims 1 to 4, wherein the vibration detection unit detects surface acoustic waves propagating on the surface of the vibrating body.

9. The detection device according to claim 8, comprising a propagation section for propagating the elastic wave, wherein the propagation speed of the elastic wave in the propagation section is slower than the propagation speed of the elastic wave in the vibrating body.

10. The detection device according to any one of claims 1 to 4, wherein the vibration detection unit detects bulk elastic waves propagating inside the vibrating body.

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