Volatile compound detection device, and volatile compound detection method

Abstract

To provide a volatile compound detection device capable of being used easily and repeatedly.SOLUTION: The volatile compound detection device includes: a light-transmissive substrate 10; a metal microstructure 20 formed over the surface of the light-transmissive substrate 10 to induce localized surface plasmon resonance; a non-porous metal oxide membrane 30 formed to cover at least the surface of the metal microstructure 20, which contains metal oxides that react with volatile compounds; a light source 40 that irradiates an inspection light 100 onto a metal microstructure 20; and an optical receiver 50 that receives at least one of transmitted light, reflected light, and scattered light of the inspection light 100 irradiated on the metal microstructure 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a detection technique, and more particularly to a volatile compound detection device and a volatile compound detection method.

Background Art

[0002] For perioperative patients (from before cancer treatment to after surgery and palliative care) and patients with dementia, etc., oral hygiene management is important for preventing oral diseases. Also, the awareness of oral hygiene management is increasing among healthy people. For example, as a measure for preventing periodontal disease, a halitosis test for measuring volatile sulfur compounds (hereinafter also referred to as "VSC") in exhaled breath is being carried out. VSC is an odorous substance produced by periodontal bacteria, and for example, hydrogen sulfide, methyl mercaptan, and dimethyl sulfide are mainly known. It is known that there is a correlation between the concentration and concentration ratio of VSC in exhaled breath and the progression of periodontal disease.

[0003] By the way, a localized surface plasmon resonance (hereinafter also referred to as "LSPR") sensor is a sensor having a metal microstructure (such as a gold nanopattern) on a light-transmissive substrate (such as quartz glass). In an LSPR sensor, when the refractive index around the metal microstructure changes due to the substance to be detected, the light absorption spectrum due to the metal microstructure changes, and thus the target substance can be detected (see, for example, Patent Documents 1 and 2).

[0004] In recent years, LSPR sensors for detecting volatile organic compounds (hereinafter also referred to as "VOC") and inorganic gases, in which a porous material is formed as a gas adsorbent on a metal microstructure, have been developed (see, for example, Patent Documents 3 and 4). Also, surface plasmon resonance (hereinafter also referred to as "SPR") sensors in which a metal oxide (such as zinc oxide or nickel-doped ITO) is formed on a thin film of silver or copper coated on an optical fiber have been reported (see, for example, Non-Patent Documents 1, 2, and 3). In such an SPR sensor, hydrogen sulfide can be detected under a nitrogen atmosphere by utilizing the fact that the light absorption wavelength changes when the metal oxide changes to a sulfide in the presence of hydrogen sulfide.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Document

[0006]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] Detection devices for volatile compounds such as VSC are required to be repeatedly usable for cost reduction. However, for example, in the optical fiber SPR sensors described in Non-Patent Documents 1 to 3, after measurement, it is necessary to perform vacuum treatment using a vacuum pump to remove the volatile compound from the detection device, and there is a problem that the sensing system becomes large.

[0008] Therefore, one of the objects of the present invention is to provide a detection device for volatile compounds that can be repeatedly used with a simple operation.

Means for Solving the Problems

[0009] The present invention includes the following embodiments. [1] A light-transmissive substrate, A metal microstructure provided on the surface of the light-transmissive substrate that generates localized surface plasmon resonance, A metal oxide non-porous film provided so as to cover at least the surface of the metal microstructure and containing a metal oxide that reacts with a volatile compound, A light source that irradiates the metal microstructure with inspection light, A light receiver that receives at least one of transmitted light, reflected light, and scattered light of the inspection light irradiated on the metal microstructure, Comprising Volatile compound detection device.

[0010] [2] Further comprising a heater for heating the light-transmissive substrate The volatile compound detection device according to [1].

[0011] [3] The heater heats the light-transmissive substrate to 300 °C or higher. The volatile compound detection device according to [2].

[0012] [4] The heater is installed so as not to overlap with the metal microstructure in a plan view of the light-transmissive substrate. The volatile compound detection device according to [2] or [3].

[0013] [5] The heater is provided on the back surface of the light-transmissive substrate and is movable in a state where it does not overlap with the metal microstructure in a plan view of the light-transmissive substrate. The volatile compound detection device according to [2] or [3].

[0014] [6] Further comprising a mirror provided on the back surface of the light-transmissive substrate. The heater is provided on the side opposite to the light-transmissive substrate of the mirror. The light source and the light receiver are installed on the surface side of the light-transmissive substrate. The volatile compound detection device according to [2] or [3].

[0015] [7] The thickness of the metal oxide non-porous film is 3 nm or more and 50 nm or less. The volatile compound detection device according to any one of [1] to [6].

[0016] [8] The volatile compound is a volatile compound containing sulfur. The volatile compound detection device according to any one of [1] to [7].

[0017] [9] The volatile compound containing sulfur is hydrogen sulfide. The volatile compound detection device according to [8].

[0018]

[10] The metal oxide non-porous film is composed of zinc oxide, titanium oxide, indium oxide, copper oxide, or a combination thereof. The volatile compound detection device according to [8] or [9].

[0019]

[11] For detecting volatile compounds contained in a gas with a relative humidity of 50% or more. The volatile compound detection device according to any one of [1] to

[10] .

[0020]

[12] For detecting volatile compounds containing sulfur in exhaled breath. The volatile compound detection device according to any one of [1] to

[11] .

[0021]

[13] It is possible to detect hydrogen sulfide at a concentration of 5 ppm or less in a gas with a relative humidity of 70%. The volatile compound detection device according to any one of [1] to

[12] .

[0022]

[14] Further comprising a dielectric layer provided between the light-transmissive substrate and the metal microstructure. The volatile compound detection device according to any one of [1] to

[13] .

[0023]

[15] Prepare a local surface plasmon resonance sensor including a light-transmissive substrate, a metal microstructure provided on the surface of the light-transmissive substrate that generates local surface plasmon resonance, and a metal oxide non-porous film provided so as to cover at least the surface of the metal microstructure and containing a metal oxide that reacts with a volatile compound. Bring the gas to be inspected into contact with the metal oxide non-porous film of the local surface plasmon resonance sensor. Detecting localized surface plasmon resonance in a metal microstructure, including, A method for detecting volatile compounds.

[0024]

[16] wherein the gas is exhaled breath, The method according to

[15] .

[0025]

[17] wherein the volatile compound is a volatile compound containing sulfur, The method according to

[15] or

[16] .

[0026]

[18] wherein the volatile compound containing sulfur is hydrogen sulfide, The method according to

[17] .

[0027]

[19] further comprising heating a light-transmissive substrate, The method according to any one of

[15] to

[18] .

[0028]

[20] (a) bringing the gas to be inspected into contact with the metal oxide non-porous film of the localized surface plasmon resonance sensor; (b) detecting localized surface plasmon resonance in the metal microstructure; (c) heating the light-transmissive substrate; The method according to

[19] , wherein the steps of (a) to (c) are repeated.

[0029]

[21] In heating, the light-transmissive substrate is heated to 300 °C or higher, The method according to

[19] or

[20] .

[0030]

[22] wherein the gas has a relative humidity of 50% or more, The method according to any one of

[15] to

[21] .

[0031]

[23] It is possible to detect hydrogen sulfide at a concentration of 5 ppm or less in a gas with a relative humidity of 70%. The method according to any one of

[15] to

[22] .

Advantages of the Invention

[0032] According to the present invention, it is possible to provide a detection device for volatile compounds that can be repeatedly used with a simple operation.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0034] Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Of course, there are also parts where the dimensional relationships and ratios are different between the drawings.

[0035] [First Embodiment] As shown in FIG. 1, the volatile compound detection device 1 according to the first embodiment includes a light-transmissive substrate 10, a metal microstructure 20 provided on the surface of the light-transmissive substrate 10 that generates localized surface plasmon resonance, and a metal oxide non-porous film 30 provided so as to cover at least the surface of the metal microstructure 20 and containing a metal oxide that reacts with a volatile compound, a light source 40 that irradiates the metal microstructure 20 with inspection light 100, and a light receiver 50 that receives at least one of transmitted light, reflected light, and scattered light (hereinafter referred to as "detection light") 150 of the inspection light 100 irradiated on the metal microstructure 20. The volatile compound detection device 1 according to the first embodiment is used for detecting a volatile compound that reacts with the metal oxide contained in the metal oxide non-porous film 30. Hereinafter, the substrate including the light-transmissive substrate 10, the metal microstructure 20, and the metal oxide non-porous film 30 is also referred to as chip C.

[0036] In the volatile compound detection device 1 according to the present embodiment, since the metal microstructure 20 and the metal oxide non-porous film 30 are provided on the light-transmissive substrate 10, for example, the metal oxide non-porous film 30 can be heated by heating the light-transmissive substrate 10. In the volatile compound detection device 1 according to the present embodiment, by heating chip C, the volatile compound that has reacted with the metal oxide contained in the metal oxide non-porous film 30 can be removed, and the metal oxide non-porous film 30 can be returned to the state before the detection of the volatile compound. Therefore, the volatile compound detection device 1 according to the present embodiment can be repeatedly used with a simple operation.

[0037] The light-transmissive substrate 10 is transparent to the light emitted by the light source 40 and is made of, for example, glass, crystalline quartz, or the like.

[0038] The metal microstructure 20 has a microstructure containing a metal and is not particularly limited as long as it can generate localized surface plasmon resonance. The metal microstructure 20 is opaque to the light emitted by the light source 40 and preferably has a pattern structure. Examples of the pattern structure include a dot pattern in which metal particles are regularly arranged in a lattice shape such as a rhombic lattice, a hexagonal lattice, a square lattice, a rectangular lattice, and a parallel lattice. In FIG. 1, the metal microstructure 20 is composed of a plurality of metal particles arranged on the light-transmissive substrate 10, but the metal microstructure may be formed by forming a plurality of holes in a metal film. That is, the metal microstructure 20 is not particularly limited as long as it has a structure that generates LSRP when the inspection light 100 is irradiated from the light source 40.

[0039] The height or depth of the metal pattern constituting the metal microstructure 20 is, for example, 10 nm or more and 100 nm or less. When each of the metal patterns is a circular dot, its diameter is, for example, 100 nm or more and 500 nm or less, but is not particularly limited. The metal constituting the metal microstructure 20 is not particularly limited, and examples thereof include gold (Au) and silver (Ag).

[0040] The metal oxide non-porous film 30 is provided so as to cover at least the surface of the metal microstructure 20. When the metal microstructure 20 has a pattern composed of a plurality of metal particles, the metal oxide non-porous film 30 is a layer that covers the light-transmissive substrate 10 and the metal particles arranged thereon.

[0041] In the volatile compound detection device according to the present embodiment, when the volatile compound reacts with the metal oxide contained in the metal oxide non-porous film 30, the refractive index of the metal oxide non-porous film 30 changes, and the change in the refractive index is detected as a change in the absorption spectrum of LSPR. Therefore, it is preferable that at least a part of the metal oxide non-porous film 30 is in contact with at least a part of the metal microstructure 20.

[0042] In this specification, when a metal oxide is "non-porous", it means that pores such as micropores, mesopores, and macropores are not formed. Note that a micropore is, for example, a pore having a pore diameter of 2 nm or less. A mesopore is, for example, a pore having a pore diameter of 2 nm or more and 50 nm or less. A macropore is, for example, a pore having a pore diameter of 50 nm or more. The fact that a metal oxide is "non-porous" can be confirmed, for example, by measuring the specific surface area or the pore distribution by a gas adsorption method. Examples of the porous body include mesoporous silica, zeolite-type imidazolate framework (ZIF), fcu-MOF, etc. disclosed in JP-A-2020-034342, and the metal oxide non-porous film 30 in the present embodiment does not include those porous bodies.

[0043] The thickness of the metal oxide non-porous film 30 is not particularly limited, but is, for example, 1 nm or more and 100 nm or less, preferably 3 nm or more and 50 nm or less. When the thickness of the metal oxide non-porous film 30 is 1 nm or more, the refractive index change around the metal microstructure 20 becomes sufficiently high when the metal oxide reacts with the volatile compound. When the thickness of the metal oxide non-porous film 30 is 100 nm or less, even when the metal oxide reacts with the volatile compound and a refractive index change occurs only in the surface portion of the metal oxide non-porous film 30, the absorption spectrum of LSPR changes sufficiently. The thickness of the metal oxide non-porous film 30 can be determined, for example, by observing a cross section in the thickness direction of the chip C with a scanning electron microscope (SEM) or the like and calculating the average value of the thickness measured at five or more points at an arbitrary point in the observation region.

[0044] The metal oxide contained in the metal oxide non-porous film 30 can be appropriately selected according to the type of volatile compound to be detected. For example, it may be zinc oxide, titanium oxide, indium oxide, copper oxide, or a combination thereof. Further, the metal oxide may be one obtained by adding a trace amount of another element (doping) to the above metal oxide. Examples of the doping element include metal elements such as Al. By appropriately selecting the metal oxide contained in the metal oxide non-porous film 30, a detection device selective to a specific volatile compound can be provided, or the sensitivity of the detection device to a desired volatile compound can be increased.

[0045] For example, when the volatile compound to be detected contains sulfur or is hydrogen sulfide, the metal oxide non-porous film 30 preferably contains zinc oxide, titanium oxide, indium oxide, copper oxide, or a combination thereof, more preferably contains zinc oxide, titanium oxide, indium oxide, or a combination thereof, and even more preferably contains zinc oxide. When the volatile compound contains sulfur, the volatile compound reacts with the metal oxide to form metal sulfide and / or metal sulfurized oxide. By using the above-mentioned metal oxide, the reactivity between the metal oxide and the volatile compound is high, or the refractive index change from the metal oxide when forming metal sulfide and / or metal sulfurized oxide is high, so that the sensitivity of the detection device can be further increased.

[0046] The inspection light 100 emitted by the light source 40 is, for example, ultraviolet light, visible light, or near-infrared light. When the chip C is irradiated with the inspection light 100, local surface plasmon resonance (LSPR) occurs in the metal microstructure 20, and an absorption peak appears in the spectrum of the light transmitted, scattered, and / or reflected by the metal microstructure 20. The absorption peak shifts in wavelength when the metal oxide non-porous film 30 of the chip C reacts with the volatile compound. The magnitude of the wavelength shift tends to be larger in the near-infrared region than in the visible light region. Therefore, when the amount of the volatile compound is small, for example, by using a light source 40 that emits near-infrared light, the volatile compound can be detected with high sensitivity.

[0047] The light receiver 50 can receive the detection light 150 transmitted, scattered, and / or reflected by the metal microstructure 20, and detect the wavelength shift caused by the reaction between the metal oxide non-porous film 30 of the chip C and the volatile compound. As the light receiver 50, a charge-coupled device (CCD) or the like can be used. A processing device such as a central processing unit (CPU) is connected to the light receiver 50. The processing device determines the presence or absence of a significant wavelength shift in the absorption peak in the spectrum of the detection light 150 detected by the light receiver 50. For example, when the intensity of light in a predetermined wavelength band changes to a value equal to or greater than a predetermined value, the processing device determines that the volatile compound to be detected is present. Further, when the intensity of light in a predetermined wavelength band does not change to a value equal to or greater than a predetermined value, the processing device determines that the volatile compound to be detected is not present. Alternatively, the processing device may calculate the concentration of the inorganic gas based on, for example, the amount of change in the intensity of light in a predetermined wavelength band.

[0048] In the volatile compound detection device 1 shown in FIG. 1, since the light source 40 and the light receiver 50 are arranged with the chip C interposed therebetween, the detection light 150 mainly includes the transmitted light obtained by the inspection light 100 passing through the chip C. In FIG. 1, the light source 40 is arranged on the side of the metal oxide non-porous film 30 of the chip C. However, the light source 40 and the light receiver 50 may be arranged in reverse, and the light receiver 50 may be arranged on the side of the metal oxide non-porous film 30 of the chip C.

[0049] Chip C may further include a dielectric layer 25 provided between the light-transmissive substrate 10 and the metal microstructure 20 as shown in FIG. 1. By providing the dielectric layer 25, Chip C can be easily manufactured by a lithography method. Although the dielectric layer is described in detail in Japanese Patent Application Laid-Open No. 2014-059316, the dielectric layer 25 may be a layer formed by dielectric treatment of a conductive layer or an adhesion layer during the manufacturing process of Chip C. The conductive layer and the adhesion layer are layers having conductivity such as metals such as Cr, Ti, Ni, or thin films of semiconductors such as Si. The dielectric layer 25 may be an oxide of a metal such as Cr, Ti, Ni, or an oxide of a semiconductor such as Si, and may be, for example, silicon dioxide (SiO2), chromium oxide (Cr2O3), nickel oxide (NiO), or titanium oxide (TiO2).

[0050] A band-pass filter that transmits light in a wavelength band where an absorbance change due to LSRP occurs may be disposed between Chip C and the light receiver 50.

[0051] The volatile compound detected by the volatile compound detection device according to the present embodiment is not particularly limited as long as it reacts with the metal oxide contained in the metal oxide non-porous film, and can be appropriately selected according to the type of the metal oxide. The volatile compound to be detected preferably contains sulfur, preferably contains at least one selected from hydrogen sulfide, methyl mercaptan, and dimethyl sulfide, and more preferably contains hydrogen sulfide.

[0052] Note that the volatile compound detection device according to the present embodiment may be used to detect a volatile compound contained in a gas having a relative humidity of 50% or more. As shown in the examples described later, the volatile compound detection device according to the present embodiment has higher detection sensitivity when detecting a volatile compound contained in a gas having a high relative humidity, for example, a gas having a relative humidity of 50% or more. Therefore, it is preferably used to detect a volatile compound contained in a gas having a relative humidity of 50% or more. From the same viewpoint, the volatile compound detection device according to the present embodiment may be used to detect a volatile compound containing sulfur in exhaled breath.

[0053] Since the volatile compound detection device according to this embodiment has high sensitivity as described above, it can detect hydrogen sulfide at a concentration of 5 ppm or less, 3 ppm or less, 1 ppm or less, 0.5 ppm or less, 0.1 ppm or less, or 0.05 ppm or less in a gas with a relative humidity of 70%.

[0054] Chip C can be manufactured, for example, by electron beam lithography or nanoimprint lithography, and can be manufactured by the nanoimprint lithography method with reference to the methods described in Patent Documents 1 to 4, for example. More specifically, with reference to the methods described in Patent Documents 1 to 4, for example, a metal microstructure 20 can be formed on the light-transmissive substrate 10 through a dielectric layer 25 by the nanoimprint lithography method.

[0055] The method for forming the metal oxide non-porous film 30 is not particularly limited, and examples include chemical vapor deposition (CVD) (particularly, an atmospheric open type chemical vapor deposition method), sputtering method, vacuum evaporation method, and the like.

[0056] The volatile compound detection device according to this embodiment can be used to detect a volatile compound that reacts with the metal oxide contained in the metal oxide non-porous film. The volatile compound detection method according to this embodiment includes preparing a localized surface plasmon resonance sensor (corresponding to Chip C in the above) including a light-transmissive substrate, a metal microstructure provided on the surface of the light-transmissive substrate that generates localized surface plasmon resonance, and a metal oxide non-porous film provided so as to cover at least the surface of the metal microstructure and containing a metal oxide that reacts with a volatile compound, bringing the gas to be inspected into contact with the metal oxide non-porous film of the localized surface plasmon resonance sensor, and detecting the localized surface plasmon resonance in the metal microstructure.

[0057] In the volatile compound detection method according to this embodiment, when bringing the gas to be inspected into contact with the metal oxide non-porous film of the localized surface plasmon resonance sensor, the gas to be inspected may be directly brought into contact with the localized surface plasmon resonance sensor in an open system, or the localized surface plasmon resonance sensor may be enclosed in a sealed container and then the gas to be inspected may be introduced into the sealed container to bring the gas to be inspected into contact with the localized surface plasmon resonance sensor.

[0058] In the volatile compound detection method according to this embodiment, detecting the localized surface plasmon resonance in the metal microstructure may include irradiating the localized surface plasmon resonance sensor with inspection light and receiving, with a light receiver, detection light that is at least one of transmitted light, reflected light, and scattered light of the inspection light. For example, the localized surface plasmon resonance can be detected by analyzing the spectrum of the received detection light.

[0059] The volatile compound detection method according to this embodiment may further include heating a light-transmissive substrate. By heating the light-transmissive substrate, the volatile compounds that have reacted with the metal oxide can be removed, and the localized surface plasmon resonance sensor can be returned to the state before detecting the volatile compounds.

[0060] The heating temperature is not particularly limited, but is, for example, 300°C or higher and 800°C or lower, preferably 400°C or higher and 600°C or lower. By setting the heating temperature to 300°C or higher, the heating time can be shortened. Also, by setting the heating temperature to 800°C or lower, changes in the metal microstructure due to heating can be suppressed. Also, the heating time is not particularly limited, but is, for example, 10 minutes or longer and 3 hours or shorter, preferably 30 minutes or longer and 2 hours or shorter.

[0061] The volatile compound detection method according to this embodiment (a) bringing the gas to be inspected into contact with the metal oxide non-porous film of the localized surface plasmon resonance sensor; (b) detecting the localized surface plasmon resonance in the metal microstructure; (c) heating the light-transmissive substrate; By repeating the steps from (a) to (c), the volatile compound may be detected repeatedly.

[0062] [Second Embodiment] FIG. 2 shows a volatile compound detection device 2 according to the second embodiment. The volatile compound detection device 2 is different from the volatile compound detection device 1 shown in FIG. 1 in that the light source 40 and the light receiver 50 are on the same side of the chip C. In the volatile compound detection device 2, the detection light 150 mainly includes the reflected light and / or scattered light of the inspection light 100. In FIG. 2, the light source 40 and the light receiver 50 are provided on the light transmissive substrate 10 side of the chip C, but the light source 40 and the light receiver 50 may be provided on the metal oxide non-porous film 30 side of the chip C. Regarding other configurations, the volatile compound detection device 2 according to the second embodiment may have the same or similar configuration as the volatile compound detection device 1 according to the first embodiment.

[0063] [Third Embodiment] FIG. 3 shows a volatile compound detection device 3 according to the third embodiment. The volatile compound detection device 3 is different from the volatile compound detection device 1 shown in FIG. 1 in that a mirror 60 is provided on the back surface of the light transmissive substrate 10 (the surface opposite to the surface where the metal microstructure 20 is provided), and the light source 40 and the light receiver 50 are on the same side of the mirror 60. In the volatile compound detection device 3, the inspection light 100 irradiated on the chip C is affected by LSPR due to the metal microstructure 20 and is reflected by the mirror 60, so that the detection light 150 is received by the light receiver 50. Regarding other configurations, the volatile compound detection device 3 according to the third embodiment may have the same or similar configuration as the volatile compound detection device 1 according to the first embodiment.

[0064] [Fourth Embodiment] FIG. 4 shows a volatile compound detection device 4 according to the fourth embodiment. The volatile compound detection device 4 is different from the volatile compound detection device 1 shown in FIG. 1 in that it further includes a heater 70 for heating the light transmissive substrate 10. Since the chip C and the heater 70 are integrally formed in the volatile compound detection device 4, the light transmissive substrate 10 can be easily heated.

[0065] The heater 70 heats the light-transmissive substrate 10 in order to return the metal oxide reacted with the volatile compound to its state before the reaction. The heating temperature is not particularly limited, but is, for example, 300°C or higher and 800°C or lower, preferably 400°C or higher and 600°C or lower.

[0066] As shown in FIG. 4, the heater 70 may be installed so as not to overlap with the metal microstructure 20 in a plan view with respect to the light-transmissive substrate 10. By arranging the heater 70 in this way, it is possible to repeatedly detect the volatile compound to be detected and heat by the heater 70 without moving the positions of the chip C, the light source 40, the light receiver 50, and the heater 70.

[0067] [Fifth Embodiment] FIG. 5 shows a volatile compound detection device 5 according to the fifth embodiment. The volatile compound detection device 5 is different from the volatile compound detection device 4 shown in FIG. 4 in that a heater 70 is provided on the back surface of the light-transmissive substrate 10 as shown in FIG. 5. In the volatile compound detection device 5, the heater 70 may be configured to be movable from a state where it is provided on the back surface of the light-transmissive substrate 10 to a state where it does not overlap with the metal microstructure 20. The volatile compound detection device 5 may include a moving mechanism 75 for moving the heater 70. The moving mechanism 75 is, for example, a motor, and by moving the heater 70, the heater 70 can be removed from the optical paths of the light source 40 and the light receiver 50.

[0068] In the volatile compound detection device 5, after heating by the heater 70, the heater 70 is moved to a state where it does not overlap with the metal microstructure 20, and then the detection of the volatile compound to be detected is performed again.

[0069] [Sixth Embodiment] FIG. 6 shows a volatile compound detection device 6 according to the sixth embodiment. The volatile compound detection device 6 is different from the volatile compound detection device 3 shown in FIG. 3 in that a heater 70 is provided on the back surface of the mirror 60 as shown in FIG. 6. In the volatile compound detection device 5, the heater 70 heats the chip C via the mirror 60.

[0070] [Other Embodiments] Although the present invention has been described by way of embodiments as described above, it should not be understood that the description and drawings forming a part of this disclosure limit the present invention. Various alternative embodiments, examples, and operational techniques should be apparent to those skilled in the art from this disclosure. It should be understood that the present invention encompasses various embodiments not described herein.

[0071] [Example 1] A chip having a dot pattern structure composed of a quartz substrate, a silicon oxide film disposed on the quartz substrate, and gold disposed in a hexagonal lattice pattern on the silicon oxide film was prepared. The thickness of each dot of the dot pattern structure was 50 nm, the diameter was 500 nm, and the interval was 1000 nm. The prepared chip was placed in a furnace, heated from room temperature to 450° C. in 0.1 hour, and then heated at 450° C. for 1 hour. Next, the chip was subjected to ozone oxidation treatment for 10 minutes, and further the chip was treated with ammonia peroxide (NH3 / H2O2 / H2O = 10 / 10 / 50 mL) at 75° C. for 5 minutes to remove impurities. Thereafter, the chip was rinsed with water and dried with a spin coater (Slope 0.1 second, rotation speed 5000 rpm, 10 seconds).

[0072] Next, a metal oxide non-porous film was formed on the surface of the chip having the metal microstructure. Specifically, zinc oxide (ZnO), titanium dioxide (TiO2), or indium oxide (In2O3) was formed by an atmospheric open-type chemical vapor deposition (CVD) method. The film formation conditions of the atmospheric open-type CVD method were adjusted so that the thickness of the metal oxide non-porous film became 20 - 30 nm.

[0073] A chip equipped with a metal oxide non-porous film was irradiated with light, and the absorbance at a specific wavelength of the light transmitted through the chip was measured. The results of measuring the absorbance for 10 minutes while exposing the chip to 2 ppm hydrogen sulfide (H2S) under 70% relative humidity (RH) are shown in FIG. 7. As shown in FIG. 7, in the chips formed of zinc oxide (ZnO), titanium dioxide (TiO2), or indium oxide (In2O3), changes in absorbance at a specific wavelength accompanying the wavelength shift of the absorption peak were observed. The absorbance increased for zinc oxide, and decreased for titanium dioxide and indium oxide. This result indicates that the detection device of Example 1 can detect hydrogen sulfide gas with high sensitivity in a short time.

[0074] [Example 2] A calibration curve was created for the detection device of Example 1. Also, the relationship between the relative humidity of the measurement gas and the change in absorbance in the detection device of Example 1, and the influence of heat treatment in the detection device of Example 1 were verified.

[0075] A chip equipped with a metal oxide non-porous film made of zinc oxide was prepared in the same manner as in Example 1. The change in absorbance before and after exposing the chip to a gas containing hydrogen sulfide at different concentrations (relative humidity 70%) for 10 minutes was measured, and the calibration curve shown in FIG. 8 was created by plotting the hydrogen sulfide concentration and the change in absorbance. As shown in FIG. 8, it was shown that 0.5 ppm of hydrogen sulfide can be detected at a relative humidity of 70%.

[0076] Next, the change in absorbance before and after exposing the chip to a gas having different relative humidities (hydrogen sulfide concentration: 1 ppm) for 10 minutes was measured, and the graph shown in FIG. 9 was created by plotting the relative humidity and the change in absorbance. As shown in FIG. 9, it was shown that the higher the relative humidity, the higher the change in absorbance, that is, the higher the sensitivity as a detection device.

[0077] Next, the chip was exposed to a gas containing hydrogen sulfide (relative humidity 70%) at each concentration from 0.05 ppm to 3 ppm for 10 minutes, and a cycle of heat treatment at 500°C for 1 hour was repeated a plurality of times. In each cycle, the change in absorbance before and after exposing the chip to the gas containing hydrogen sulfide was measured. FIG. 10 shows the relationship among the hydrogen sulfide concentration, the number of heating times, and the change amount of absorbance. As shown in FIG. 10, the detection device of this example had no influence on the detection sensitivity even when repeatedly used by heating.

Explanation of Reference Numerals

[0078] 1, 2, 3, 4, 5, 6... volatile compound detection device, 10... light-transmissive substrate, 20... metal microstructure, 25... dielectric layer, 30... metal oxide non-porous film, 40... light source, 50... light receiver, 60... mirror, 70... heater, 75... moving mechanism, 100... inspection light, 150... detection light, C... chip.

Claims

1. A light-transmissive substrate, a metal microstructure provided on the surface of the light-transmissive substrate that generates localized surface plasmon resonance, a metal oxide non-porous film provided so as to cover at least the surface of the metal microstructure and containing a metal oxide that reacts with a volatile compound, a light source that irradiates the metal microstructure with inspection light, a light receiver that receives at least one of transmitted light, reflected light, and scattered light of the inspection light irradiated on the metal microstructure, and a volatile compound detection device comprising the above.

2. The volatile compound detection device according to claim 1, further comprising a heater for heating the light-transmissive substrate.

3. The volatile compound detection device according to claim 2, wherein the heater heats the light-transmissive substrate to 300°C or higher.

4. The volatile compound detection device according to claim 2, wherein the heater is installed so as not to overlap the metal microstructure in a plan view with respect to the light-transmissive substrate.

5. The volatile compound detection device according to claim 2, wherein the heater is provided on the back surface of the light-transmissive substrate and is movable in a state where it does not overlap the metal microstructure in a plan view with respect to the light-transmissive substrate.

6. The volatile compound detection device according to claim 2, further comprising a mirror provided on the back surface of the light-transmissive substrate, wherein the heater is provided on the side of the mirror opposite to the light-transmissive substrate, and the light source and the light receiver are installed on the surface side of the light-transmissive substrate.

7. The volatile compound detection device according to any one of claims 1 to 6, wherein the thickness of the metal oxide non-porous film is 3 nm or more and 50 nm or less.

8. The volatile compound detection device according to any one of claims 1 to 6, wherein the volatile compound is a volatile compound containing sulfur.

9. The volatile compound detection device according to claim 8, wherein the volatile compound containing sulfur is hydrogen sulfide.

10. The volatile compound detection device according to claim 8, wherein the metal oxide non-porous film is composed of zinc oxide, titanium oxide, indium oxide, copper oxide, or a combination thereof.

11. For detecting a volatile compound contained in a gas with a relative humidity of 50% or more, The volatile compound detection device according to any one of claims 1 to 6.

12. For detecting a volatile compound containing sulfur in exhaled breath, The volatile compound detection device according to any one of claims 1 to 6.

13. It is capable of detecting hydrogen sulfide at a concentration of 5 ppm or less in a gas with a relative humidity of 70%. The volatile compound detection device according to any one of claims 1 to 6.

14. Further comprising a dielectric layer provided between the light-transmissive substrate and the metal microstructure. The volatile compound detection device according to any one of claims 1 to 6.

15. Providing a localized surface plasmon resonance sensor comprising a light-transmissive substrate, a metal microstructure provided on the surface of the light-transmissive substrate that generates localized surface plasmon resonance, and a metal oxide non-porous film containing a metal oxide that reacts with a volatile compound and is provided so as to cover at least the surface of the metal microstructure; Bringing the gas to be inspected into contact with the metal oxide non-porous film of the localized surface plasmon resonance sensor; Detecting the localized surface plasmon resonance in the metal microstructure; Including A method for detecting a volatile compound.

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