WO2003005001A1

WO2003005001A1 - Method and device for detecting chemical substance

Info

Publication number: WO2003005001A1
Application number: PCT/JP2002/006480
Authority: WO
Inventors: Kazuyuki Maruo
Original assignee: Advantest Corporation
Priority date: 2001-07-05
Filing date: 2002-06-27
Publication date: 2003-01-16
Also published as: JP2003014642A

Abstract

A chemical substance detecting device, comprising a substrate sealing container (18) for leading measured gas therein, a sampling pump (20) for leading the measured gas into the substrate sealing container (18) so that a pressure in the substrate sealing container (18) becomes positive, an infrared transmission substrate (10) put inside the substrate sealing container (18) and adsorbing chemical substances contained in the measured gas, an incident optical system (30) for letting infrared ray onto the infrared transmission substrate (10), and an FT-IR device (46) for determining the type of the chemical substances contained in the measured gas and/or calculating the density of the chemical substances by analyzing the infrared ray emitted after being passed through the infrared transmission substrate (10), whereby, since a detection sensitivity in the conventional method and device for chemical substance can be further increased, the chemical substance can be detected with high accuracy in real time.

Description

Description Chemical substance detection method and device

[Technical field]

The present invention relates to a chemical substance detection method and apparatus capable of detecting a chemical substance present in the environment at high speed and with high sensitivity.

[Background technology]

Monitoring of chemicals present in the environment is rapidly gaining importance in our real-life environment.

For example, in recent years, environmental pollution caused by trace amounts of chemical substances such as dioxins emitted from garbage incineration facilities has attracted attention.

In addition, there have been reports of cases in which chemicals called volatile organic compounds (VOCs) contained in building materials for new homes and condominiums vaporize indoors and cause health problems for residents. This is a major problem.

Conventional methods for measuring chemical substances present in the environment include, for example, adsorbing the gas to be measured on a porous substance such as TENAX, heating the gas, releasing the adsorbed chemical substance, and using a mass spectrometer. Method for identification and quantification of chemical substance components (Heating desorption GC-MS: Gas Chromatography-Mass Spectroscopy) Further, as another method for measuring the chemicals present in the environment, and irradiating infrared rays onto the measuring object gas, the absorption spectrum for the spectral analysis, so-called FT- IR (Fourier Transform Infrared Spectroscopy) force is ^¾.

However, thermal desorption GC-MS requires a long time for measurement and lacks real-time measurement, making it difficult to measure the environment on the spot. On the other hand, with the FT-IR, it was necessary to secure an enormous infrared light path to increase the detection sensitivity, and in practice, it was difficult to detect trace amounts of chemical substances in the environment with high sensitivity. As described above, the conventional method cannot measure chemical substances existing in the environment with high sensitivity and in real time.

From this point of view, the present inventors have already proposed a chemical substance detection method and apparatus capable of detecting a chemical substance present in the environment with high sensitivity and in real time (for example, see Japanese Patent Application Laid-Open No. 2001-016). No. 8863).

FIG. 5 is a schematic diagram showing the structure of an example of a chemical substance detection device proposed by the present inventors. As shown in the figure, an infrared transmitting substrate 100 for attaching a chemical substance in a gas to be measured for measurement is placed on a support 102. The support 102 is provided with a cooling device 104 so that the infrared transmitting substrate 100 can be cooled.

The infrared transmitting substrate 100 is enclosed in a substrate enclosure 110 having an intake port 106 through which the gas to be measured is introduced and an exhaust port 108 through which the gas to be measured is exhausted. ing. On one side surface of the substrate enclosing container 110, an entrance window 112 made of a material that is transparent to infrared rays is provided. A detection window 114 made of a material that is transparent to infrared rays is provided on the side surface opposite to one side surface on which the entrance window 112 is provided, similarly to the entrance window 112.

The substrate enclosing container 110 is provided with a heating device 116 so that the entire substrate enclosing container 110 including the infrared transmitting substrate 100 can be heated. A sampling pump 118 for flowing the gas to be measured in the substrate enclosure 110 is connected to the exhaust port 108 of the substrate enclosure 110.

An incident optical system 120 is arranged near an entrance window 112 provided on one side surface of the substrate enclosure 110. The incident optical system 120 is composed of an infrared light source 122 that emits infrared light serving as probe light, a reflecting mirror 122 that guides infrared light emitted from the infrared light source 122 to the concave mirror 124, and a reflection. It is composed of a concave mirror 124 that collects the infrared light guided from the mirror 126 and introduces it into the infrared transmitting substrate 100 so that the infrared light is reflected multiple times from the end face.

In the vicinity of the detection window 114 provided on the other side of the substrate enclosing container 110, a transparent infrared ray emitted after multiple reflection inside the infrared transmitting substrate 100 is detected and spectrally separated. FT-IR (Fourier transform infrared spectroscopy) device 1 6 0 is arranged through. The detection optical system 130 collects the infrared light emitted from the end face of the infrared transmitting substrate 100 and guides it to the reflecting mirror 132, and the infrared light collected by the concave mirror 133. It is composed of a reflecting mirror 1 32 which reflects the light to the FT-IR device 1 36.

The FT-IR device 1336 has a calculation and display device (not shown) that identifies the type of chemical substance in the gas to be measured and calculates the concentration based on the analysis result of the FT-IR device 1336. It is connected.

In the above-described chemical substance detection device proposed by the present inventor, the gas to be measured is caused to flow in the substrate enclosure 110 by the sampling pump 118. At the same time, the infrared transmitting substrate 100 is cooled by the cooling device 104. Thereby, the adhesion of the chemical substance in the gas to be measured to the surface of the infrared transmitting substrate 100 is promoted.

Then, the chemical substance attached to the surface of the infrared transmitting substrate 100 is detected by the infrared multiple internal reflection FT-IR method. That is, infrared rays are incident on one end of the infrared transmitting substrate 100 in the substrate enclosing container 110 by the incident optical system 120 so as to be reflected multiple times inside the substrate. Infrared rays that have entered the inside of the infrared transmitting substrate 100 are resonantly absorbed when the frequency component of the light that seeps out when reflected on the substrate surface matches the molecular vibration frequency of the chemical substance attached to the substrate surface. . The infrared radiation emitted from the other end of the infrared transmitting substrate 100 is spectrally analyzed by an FT-IR device 136 to identify the type of chemical substance attached to the infrared transmitting substrate 100 and to determine the amount of the attached chemical substance. Is calculated. Based on the measurement result of the chemical substance attached to the infrared transmitting substrate 100, the type and concentration of the chemical substance in the gas to be measured are estimated. In this way, it is possible to detect chemical substances in the gas to be measured in real time with high sensitivity.

In the conventional chemical substance detection device shown in FIG. 5, as described above, the attachment of the chemical substance to the infrared transmitting substrate 100 is performed by flowing the gas to be measured near the infrared transmitting substrate 100, This was promoted by cooling the infrared transmitting substrate 100. Thus, the sensitivity of detecting the chemical substance in the gas to be measured has been improved by increasing the amount of the chemical substance attached to the infrared transmitting substrate 100. According to the experimental results, it has been confirmed that the chemical substance detection device shown in Fig. 5 can achieve a detection sensitivity on the order of lOppb (parts per billion). With this level of sensitivity If present, it could be sufficiently practical for some types of chemical substances to be detected.o

However, the Ministry of Health, Labor and Welfare and the Ministry of the Environment have set emission standards for VOC concentrations as guidelines, for example, for the concentration of formaldehyde in indoor environments.

The emission standard is below 0.8 ppm (parts per million) (80 pb). In order to quantitatively detect a trace amount of a chemical substance in the environment at such an emission standard concentration, it is necessary to have a detection sensitivity of at least 0.001 Ppm order, preferably lppb. In other words, in order to detect a very small amount of VOC, which is about the emission standard set by the Ministry of Health, Labor and Welfare, with high accuracy, it is necessary to further improve the detection sensitivity of the conventional chemical substance detection method and apparatus shown in FIG.

[Disclosure of the Invention]

An object of the present invention is to provide a chemical substance detection method and apparatus capable of detecting a chemical substance with high accuracy and in real time by further improving the detection sensitivity of the conventional chemical substance detection method and apparatus.

The object is to provide a chemical substance detection method for detecting a chemical substance contained in a gas to be measured by irradiating an infrared ray to a substrate exposed to the gas to be measured and analyzing infrared light emitted from the substrate. Storing the substrate in a container, introducing the gas to be measured into the container and applying a positive pressure to the container to promote the chemical substance to adhere to the substrate. This is achieved by the chemical substance detection method described above.

Further, in the chemical substance detection method described above, the positive pressure state in the container may be adjusted by exhausting the gas to be measured introduced into the container from the container.

Further, in the above chemical substance detection method, the substrate may be cooled to further promote the chemical substance in the gas to be measured to adhere to the substrate.

Further, in the chemical substance detection method described above, by analyzing infrared rays emitted after multiple reflection inside the substrate, the chemical substance in the gas to be measured is analyzed. The type of quality may be identified and / or the concentration of the chemical substance may be calculated. Further, in the chemical substance detection method described above, the object to be measured is analyzed by analyzing infrared rays that are incident from one surface side of the substrate, transmitted through the substrate, and emitted from the other surface side of the substrate. The type of the chemical substance in the gas may be identified and / or the concentration of the chemical substance may be calculated.

In the above-described chemical substance detection method, the chemical substance attached to the substrate may be periodically removed to initialize the surface state of the substrate.

Further, the above object is to provide a container for introducing a gas to be measured, gas introducing means for introducing the gas to be measured into the container such that the pressure in the container is positive, A substrate mounted thereon, to which a chemical substance contained in the gas to be measured is attached, infrared radiation incident means for irradiating infrared radiation to the substrate, and analyzing infrared radiation emitted after passing through the substrate, A chemical substance detection device comprising: a chemical substance detection unit that identifies a type of the chemical substance in the gas to be measured and calculates Z or the concentration of the chemical substance.

The above-mentioned chemical substance detection device may further include exhaust control means for controlling exhaust of the gas to be measured introduced into the container from the inside of the container.

Further, in the chemical substance detection device, the container has first and second windows made of a material that transmits infrared light, and the infrared incident means is provided outside the container through the first window. The chemical substance detecting means is configured to detect the infrared ray emitted through the second window to the outside of the container after passing through the substrate or reflected on the surface of the substrate, The infrared light emitted to the outside of the container through the window may be analyzed.

In the above chemical substance detection device, the chemical substance detection means identifies the type of the chemical substance in the gas to be measured by analyzing infrared rays emitted after multiple reflection inside the substrate. And / or the concentration of the chemical substance may be calculated.

In the above chemical substance detection device, the chemical substance detection means is incident on one surface of the substrate, transmitted through the substrate, and emitted from the other surface of the substrate. The type of the chemical substance in the gas to be measured may be identified, and Z or the concentration of the chemical substance may be calculated by analyzing the infrared rays.

In the above-described chemical substance detection device, a cooling device that cools the substrate and promotes the chemical substance in the gas to be measured to adhere to the substrate may be further provided.

In the above chemical substance detection device, the cooling device is a device that directly contacts the substrate to cool the substrate, and the infrared incident means is configured such that a contact portion between the substrate and the cooling device is an infrared ray. Infrared light may be incident so that it is not located on the optical path of the light.

In the above chemical substance detection device, the apparatus may further include a substrate cleaning means for removing the chemical substance attached to the substrate surface and initializing the surface state of the substrate.

In the above-described chemical substance detection device, the substrate cleaning unit may be a heating unit that removes the chemical substance attached to the substrate by heating the substrate.

In the above chemical substance detection device, the substrate cleaning means may be an ultraviolet ray irradiating means for irradiating the surface of the substrate with ultraviolet rays to remove the chemical substance attached to the substrate.

According to the present invention, there is provided a chemical substance detection method for detecting a chemical substance contained in a gas to be measured by irradiating infrared rays to a substrate exposed to the gas to be measured and analyzing infrared rays emitted from the substrate. Since the substrate is housed in a container, and the gas to be measured is introduced into the container and the inside of the container is made to have a positive pressure, chemical substances are promoted to adhere to the substrate. The detection sensitivity of chemical substances used.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the structure of a chemical substance detection device according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing the structure of a modification of the chemical substance detection device according to one embodiment of the present invention. It is a schematic diagram.

FIG. 3 is a schematic diagram showing the structure of a modification of the chemical substance detection device according to one embodiment of the present invention.

FIG. 4 is a schematic view showing the structure of a modification of the chemical substance detection device according to one embodiment of the present invention.

FIG. 5 is a schematic diagram showing the structure of a conventional chemical substance detection device. [Best Mode for Carrying Out the Invention]

A chemical substance detection method and apparatus according to one embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing the structure of the chemical substance detection device according to the present embodiment.

[1] Chemical substance detection device

First, the chemical substance detection device according to the present embodiment will be explained with reference to FIG. As shown in FIG. 1, in the chemical substance detection device according to the present embodiment, an infrared transmitting substrate 10 for attaching a chemical substance in a gas to be measured and performing the measurement is mounted on a support 12. I have.

The infrared transmitting substrate 10 is sealed in a substrate sealing container 18 having an inlet 14 into which the gas to be measured is introduced and an outlet 16 from which the gas to be measured is exhausted. The sampling pump 20 that introduces the gas to be measured into the substrate enclosure 18 and makes the substrate enclosure 18 positive pressure is introduced into the inlet 14 of the substrate enclosure 18 via piping 21. It is connected.

A pipe 24 having a stop valve 22 is connected to an exhaust port 16 of the substrate enclosing container 18 so that the exhaust from the substrate enclosing container 18 can be controlled.

One side of the substrate enclosure 18 is an entrance window made of a material that is transparent to infrared rays.

26 are provided. A detection window 28 made of a material that is transparent to infrared rays is provided on a side surface opposite to the one side surface provided with the entrance window 26, similarly to the entrance window 26.

In the vicinity of the entrance window 26 provided on one side of the substrate enclosure 18, an entrance optical system

30 are located. The incident optical system 30 is composed of an infrared light source 32 that emits infrared light serving as probe light, and a reflecting mirror that guides infrared light emitted from the infrared light source 32 to the concave mirror 34. 36, and a concave mirror 34 that collects the infrared light guided from the reflecting mirror 36 and introduces it through the entrance window 26 through the infrared transmitting substrate 10 from the end face so as to cause multiple reflection inside. ing.

In the vicinity of the detection window 28 provided on the other side of the substrate enclosing container 18, a FT-IR (Fourier) is used for spectral analysis of transmitted infrared rays emitted after multiple reflections inside the infrared transmitting substrate 10. Conversion infrared spectroscopy) The device 46 is arranged via the detection optical system 40. The detection optical system 40 is composed of a concave mirror 44, which collects infrared light emitted from the infrared transmitting substrate 10 through the detection window 28 through the detection window 28, and guides the infrared light to the reflecting mirror 42, and a concave mirror. And a reflector 42 for guiding the infrared light guided from 44 to the FT-IR device 46.

The FT-IR device 46 is connected to a calculation and display device (not shown) that identifies the type of chemical substance in the gas to be measured and calculates the concentration based on the analysis results of the FT-IR device 46. ing.

The main feature of the chemical substance detection device according to the present embodiment is that it has a sampling pump 20 that introduces a gas to be measured into the substrate enclosure 18 and applies a positive pressure to the substrate enclosure 18. Thus, the adhesion rate of the chemical substance in the gas to be measured to the infrared transmitting substrate 1 can be improved, and the detection sensitivity of the chemical substance can be improved.

Hereinafter, each component of the chemical substance detection device according to the present embodiment will be individually described in detail.

(a) Infrared transmitting substrate 10

The infrared transmitting substrate 10 is for adsorbing a chemical substance in the gas to be measured for use in the measurement. Therefore, it must be a material that transmits light in the wavelength range corresponding to the molecular vibration of the chemical substance to be detected. The wave number range corresponding to the fundamental vibration of a typical organic substance is from 500 cm- ¹ (wavelength 20 μππ) to 500 cm- ¹ (wavelength 2 m). Outer area. A substance that transmits at least the wave number band of infrared absorption caused by a specific type of molecular vibration common to the substances, for example, the wave number region corresponding to CH ₃ asymmetric stretching vibration, within the wave number range of infrared absorption of this organic substance Is selected as the infrared transmitting substrate 10. When detecting chemical substances, the infrared-transparent substrate 10 Therefore, the material must be non-deliquescent.

Therefore, for example, gallium arsenide (GaAs) has a transmission wavelength range of about 1.0 to 18 m, and is a stable substance in the atmosphere. Can be selected as material. In addition to gallium arsenide, zinc selenide (ZnSe: transmission wavelength range 0.6 to 13 μπα), silicon (Si: transmission wavelength range 1.2 μm to 6 μm), bromide power Lium (KBr: Transmission wavelength range 0, 4 to 22 μm), Calcium fluoride (C a F ₂ : Transmission wavelength range 0.2 to 8 μm), Germanium

(Ge: transmission wavelength range 2 to 18 xm) can be selected as the material of the infrared transmission substrate 10.

The shape of the infrared transmitting substrate 10 is desirably polished, for example, such that the inclination of the end face is 45 degrees. By doing so, it is possible to increase the efficiency of incidence of infrared rays into the infrared transmitting substrate 10 and to make the infrared rays undergo multiple reflection inside the infrared transmitting substrate 10. Further, in order to prevent light from being scattered when infrared rays undergo multiple internal reflections, it is necessary to use a substrate polished on both sides as the infrared transmitting substrate 10.

(b) Support 1 2

An infrared transmitting substrate 10 is placed on the support 12. At this time, beneath the infrared transmitting substrate 10, the chemical substance in the gas to be measured adheres not only to the upper surface of the infrared transmitting substrate 10 but also to the lower surface of the infrared transmitting substrate 10. A device may be designed so that the side surface and the support 12 do not completely adhere to each other. For example, a plurality of convex structures are provided on the mounting surface of the support 12, and the infrared transmitting substrate 10 is mounted thereon. Then, the lower surface of the infrared transmitting substrate 10 is exposed to the gas to be measured. As a result, the area of the infrared transmitting substrate 10 to which the chemical substance can adhere is increased, and the signal-to-noise ratio (S / N ratio) can be improved.

(c) Substrate enclosure 18 and sampling pump 20

An infrared transmitting substrate 10 is accommodated in the substrate enclosing container 18, and a gas to be measured is introduced from the introduction port 34 by the sampling pump 20. At this time, the structure of the substrate enclosing container 18 is a structure that can maintain airtightness so that the inside of the substrate enclosing container 18 is at a positive pressure. The stop valve 22 provided in the pipe 24 connected to the exhaust port 16 of the substrate enclosure 18 controls the exhaust from the substrate enclosure 18. When introducing the gas to be measured into the substrate enclosure 18 by the sampling pump 20, the stop valve 22 is closed and the substrate enclosure 18 is closed. As a result, the inside of the substrate enclosing container 18 can be maintained at a positive pressure.

The entrance window 26 provided on the side surface of the substrate enclosing container 18 is for introducing infrared rays to the end face of the infrared transmitting substrate 10 housed in the substrate enclosing container 18 by the incident optical system 30.

The detection window 28 receives the infrared light emitted from the end face after multiple reflection inside the infrared transmitting substrate 10 accommodated in the substrate enclosing container 18 through the detecting optical system 40 and the FT-IR device. 4 for detection by 6.

As described above, in the chemical substance detection device according to the present embodiment, by providing the entrance window 26 and the detection window 28 in the substrate enclosure 18, the incident optical system 30, the detection optical system 40, and the FT_IR The device 46 is placed outside the substrate enclosure 18. As a result, the substrate enclosure 18 itself can be made compact, and the time required for measurement such as introduction and exhaust of the gas to be measured into the substrate enclosure 18 can be reduced. .

The sampling pump 20 has an intake port 48 for sucking the gas to be measured from the environment, and an exhaust port 50 for discharging the sucked gas to be measured to a positive pressure. The exhaust port 50 of the sampling pump 22 is connected to the inlet port 14 of the substrate enclosure 18 via a pipe 21. The sampling pump 20 introduces the gas to be measured sucked from the intake port 48 into the substrate enclosure 18 via the pipe 21, and makes the inside of the substrate enclosure 18 a positive pressure. Hereinafter, the effect obtained by making the inside of the substrate enclosing container 18 a positive pressure by the sampling pump 20 will be described in detail.

In general, the amount of gas adsorbed on a solid surface increases as the partial pressure of gas molecules increases. Several models have been proposed to represent the relationship between the gas partial pressure and the amount of adsorption depending on the adsorption conditions. Freundlich's adsorption equation, which is one of the representative models, is expressed by the following equation, where the amount of adsorbed gas is w and the partial pressure of the gas is p. w = k ^{1 / n}

Here, k and n are constants depending on the type of the solid as the adsorbent or the gas as the adsorbate, the adsorption temperature, and the like.

As is clear from the above equation, when the pressure in the vicinity of the infrared transmitting substrate 10 is increased by making the inside of the substrate enclosing container 18 positive by the sampling pump 20, the infrared transmission of the chemical substance in the gas to be measured is increased. The amount of adsorption to the substrate 10 can be increased. This makes it possible to relatively improve the detection sensitivity of the chemical substance detection device.

As described above, the chemical substance detection device according to the present embodiment uses the sampling pump 20 to apply a positive pressure to the inside of the substrate enclosing container 18 and to determine the amount of the chemical substance in the gas to be measured adhering to the infrared transmitting substrate 10. The main characteristic is that the detection sensitivity is increased by increasing the detection sensitivity.

(f) Incident optical system 30 (infrared light source 32, reflecting mirror 36, concave mirror 34)

As the infrared light source 32, a light source that emits infrared light in a band of 2 to 25 μm corresponding to molecular vibration of organic molecules can be applied. For example, heat rays generated by applying a current to a silicon carbide (SiC) as a filament or a nichrome wire can be used as a light source. Light sources that use SiC, such as SiC glower lamps, emit infrared light in the 1.1 to 25 μκ band and do not burn out when used in the air.

The reflecting mirror 36 and the concave mirror 34 are for introducing infrared light emitted from the infrared light source 32 from the end face of the infrared transmitting substrate 10 so that the infrared light is multiply reflected inside the infrared transmitting substrate 10. .

The setting of the incident angle of infrared rays is described in detail in, for example, Japanese Patent Application No. 11-95853 by the same applicant.

(d), detection optics 40 (concave mirror 44, reflection mirror 42), FT-IR device 46 concave mirror 44 and reflection mirror 42 reflect infrared light after multiple reflection inside infrared transmission substrate 10. The infrared rays emitted from the end face of the transmission substrate 10 are guided to the FT-IR device 46.

The FT-IR device 46 uses, for example, a mechanism of Fourier transform spectroscopy based on a two-beam interferometer (Michelson optical interferometer) to transmit infrared light guided by a reflecting mirror 42. Is subjected to spectral analysis. Alternatively, instead of the FT-IR device 46, an infrared spectrometer using a diffraction grating (grating) may be used.

(e) Calculation and display device

The spectrum measurement data obtained by the FT-IR device 46 is sent to a calculation and display device, where the identification and the amount of chemical substances present in the gas to be measured are performed. The types of chemical substances present in the gas to be measured and the calibration curve are separately stored as a database and stored in the storage unit of the display device, and the measured data is quantified with reference to those databases. .

In order to identify chemical substances in the gas to be measured, the wave numbers of infrared absorption due to various molecular vibrations of various substances are stored in a calculation and display device as a database. For example, for each chemical substance, data on the number of absorption waves due to CH ₃ symmetric stretching vibration, CH ₃ asymmetric stretching vibration, CH ₂ symmetric stretching vibration, CH ₂ asymmetric stretching vibration, and the like are stored. When identifying a chemical substance, data on the absorption wave number due to a specific molecular vibration is referred to from the database of the absorption wave number due to various molecular vibrations.

[2] Chemical substance detection method

Next, the chemical substance detection method according to the present embodiment will be described with reference to FIG. First, the chemical substance detection device according to the present embodiment is installed in the environment to be measured. Next, the sampling pump 20 is operated, and the gas to be measured is introduced into the substrate enclosure 18 from the introduction port 14. At this time, the stop valve 22 of the pipe 24 connected to the exhaust port 16 of the substrate enclosure 18 is closed. By introducing the gas to be measured into the sealed substrate enclosing container 18 in this manner, the inside of the substrate enclosing container 18 becomes a positive pressure. It is desirable that the stop valve 22 be closed after the inside of the substrate enclosure 18 is replaced with the gas to be measured. In addition, it is desirable to appropriately control the operation of the sampling pump 20 according to the pressure in the substrate enclosure 18 and the like.

After a lapse of a predetermined time required for the chemical substance in the gas to be measured to adhere to the surface of the infrared transmitting substrate 10, the infrared light is reflected multiple times inside the infrared transmitting substrate 10 by the incident optical system 30. The infrared transmitting substrate 10 is introduced into the inside from the end face.

The infrared light introduced into the infrared transmitting substrate 10 propagates while undergoing multiple reflections inside the infrared transmitting substrate 10. Subsequently, the infrared light emitted from the end face after multiple reflection inside the infrared transmitting substrate 10 is guided to the FT-IR device 46 by the detection optical system 40. Then, the infrared ray is spectrally analyzed by the FT-IR device 46 to obtain an infrared transmission spectrum. Subsequently, based on the measurement results obtained as described above, the chemical substances present in the gas to be measured are analyzed, their types are identified, and / or the amount of adhesion is calculated. The method of identifying the type of chemical substance and calculating the amount of the attached chemical substance is described in detail, for example, in Japanese Patent Application No. 2001-68863.

Next, the above measurement is repeated as necessary to measure the change with time of the chemical substance in the gas to be measured.

After the measurement is completed, the stop valve 22 of the pipe 24 connected to the exhaust port 16 of the substrate enclosure 18 is opened, and the gas to be measured in the substrate enclosure 18 is exhausted.

As described above, according to the present embodiment, by introducing the gas to be measured in the sealed substrate enclosing container 18 to make the substrate enclosing container 18 a positive pressure, the chemical substance in the gas to be measured is Since the adhesion to the infrared transmitting substrate 10 is promoted, the detection sensitivity of the chemical substance can be improved.

: (Modified embodiment)

Various modifications are possible without being limited to the above embodiment of the present invention.

For example, as shown in FIG. 2, a cooling device 52 for cooling the infrared transmitting substrate 10 to promote the adhesion of the chemical substance in the gas to be measured may be provided. As the cooling device 52, for example, a cooling device using a Peltier element can be used. The infrared transmitting substrate 10 is cooled by the cooling device 52 together with the introduction of the gas to be measured into the substrate enclosing container 18 by the sampling pump 20. The effect of improving the adhesion rate of the chemical substance in the gas to be measured by this cooling and the effect of improving the adhesion rate by making the inside of the substrate enclosure 18 positive pressure described above work synergistically, and further detect the chemical substance. Sensitivity can be improved. '

In the case where the infrared transmitting substrate 10 is directly bonded and cooled by the cooling device 52, the cooling device 52 may be bonded to the surface of the infrared transmitting substrate 10 that is out of the optical path of the infrared light that multiple-reflects the inside. desirable. By thus indirectly cooling the region of the infrared transmitting substrate 10 which will be the infrared optical path by heat conduction, the influence of the bonding surface on the infrared absorption is reduced. Can be avoided.

The cooling of the infrared transmitting substrate 10 may be performed not only by directly cooling the infrared transmitting substrate 10 but also by cooling the support 12 supporting the infrared transmitting substrate 10. Further, as shown in FIG. 2, a heating device 54 for heating the infrared transmitting substrate 10 and / or the substrate enclosing container 18 may be provided. After or before the measurement, the infrared transmitting substrate 10 and / or the substrate enclosing container 18 is heated by the heating device 54 to the infrared transmitting substrate 10 and / or the substrate enclosing container 18. The attached chemicals can be removed. As a result, each measurement can be started with the measurement conditions initialized, and a highly accurate measurement result can be obtained.

Further, a device for irradiating the infrared transmitting substrate 10 with infrared rays may be provided in order to remove a chemical substance attached to the surface of the infrared transmitting substrate 10. By irradiating the infrared transmitting substrate 10 with ultraviolet rays, the chemical substances attached to the surface of the infrared transmitting substrate 10 are reduced by the oxidizing power of ozone generated when the ultraviolet rays are irradiated into the atmosphere and the energy of the ultraviolet rays themselves. Can be disassembled and removed.

In the above embodiment, the substrate enclosing container 18 is provided with the entrance window 26 and the detection window 28, and the incident optical system 30, the detection optical system 40, and the FT-IR device 46 are respectively connected to the substrate enclosing container 18. However, these may be arranged in the substrate enclosing container 18 so that the entrance window 26 and the detection window 28 are not provided.

In the above-described embodiment, the chemical substance in the gas to be measured is attached to the infrared transmitting substrate 10 and the chemical substance attached to the infrared transmitting substrate 10 is detected by the infrared multiple internal reflection method. However, the method of detecting a chemical substance is not limited to this. FIG. 3 and FIG. 4 are schematic diagrams showing a configuration example of a chemical substance detection device when another detection method is used.

For example, as shown in FIG. 3, a method of irradiating the surface of the infrared transmitting substrate 10 with infrared rays and detecting and spectrally analyzing the infrared rays transmitted through the infrared transmitting substrate 10 may be used. In this case, as shown in the figure, an infrared light source 56 for irradiating infrared rays to the surface of the infrared transmitting substrate 10 is arranged near one surface of the infrared transmitting substrate 10 accommodated in the substrate enclosing container 18. It has been. In the vicinity of the surface of the infrared transmitting substrate 10 facing the surface on which the infrared light source 56 is disposed, a spectroscopic analyzer 58 for spectrally analyzing the infrared light transmitted through the infrared transmitting substrate 10 is disposed. Have been.

Further, as shown in FIG. 4, instead of one infrared transmitting substrate, multiple reflection of a parallel plate can be used. In this case, as shown in the figure, the substrate enclosing container 18 accommodates a pair of substrates 60a and 60b arranged substantially in parallel. In the vicinity of one end surface of the substrates 60a and 60b, an infrared light source 62 for injecting infrared light serving as probe light between the substrates 60a and 60b is arranged. Infrared light from the infrared light source 62 is incident so that multiple reflection occurs between the opposing substrates 60a and 60b. In the vicinity of the end face opposite to the end face on which the infrared light sources 62 of the substrates 60a and 60b are arranged, the infrared light emitted after multiple reflection between the opposing substrates 60a and 60b is dispersed. Analyze FT—IR device 6 6 is connected. In the case of the configuration shown in FIG. 4, the substrates 60a and 60b need not be transparent to infrared rays.

[Possibility of industrial use]

INDUSTRIAL APPLICABILITY The method and apparatus for detecting a chemical substance according to the present invention detect various chemical substances present in the environment at high speed and with high sensitivity for the purpose of specifying the source of the chemical substance, controlling and managing the amount of release to the environment, and the like. Especially useful.

Claims

The scope of the claims

1. A chemical substance detection method for detecting a chemical substance contained in a gas to be measured by irradiating infrared rays to a substrate exposed to the gas to be measured and analyzing infrared rays emitted from the substrate,

By accommodating the substrate in a container and introducing the gas to be measured into the container to make the inside of the container positive pressure, the chemical substance is promoted to adhere to the substrate.

A method for detecting a chemical substance, comprising:

2. In the method for detecting a chemical substance according to claim 1,

The positive pressure state in the container is adjusted by exhausting the gas to be measured introduced into the container from the inside of the container.

A method for detecting a chemical substance, comprising:

3. The chemical substance detection method according to claim 1, wherein the substrate is cooled to further promote the chemical substance in the gas to be measured to adhere to the substrate.

A method for detecting a chemical substance, comprising:

4. The method for detecting a chemical substance according to any one of claims 1 to 3,

The type of the chemical substance in the gas to be measured is identified and / or the concentration of the chemical substance is calculated by analyzing infrared light emitted after multiple reflection inside the substrate.

A method for detecting a chemical substance, comprising:

5. The method for detecting a chemical substance according to any one of claims 1 to 3, wherein

The type of the chemical substance in the gas to be measured is identified by analyzing infrared light that is incident from one surface side of the substrate and transmitted through the substrate and emitted from the other surface side of the substrate. And / or calculate the concentration of said chemical substance

A method for detecting a chemical substance, comprising:

6. The method for detecting a chemical substance according to any one of claims 1 to 5,

Periodically remove the chemical substance attached to the substrate to initialize the surface state of the substrate

A method for detecting a chemical substance, comprising:

7. A container for introducing the gas to be measured,

Gas introducing means for introducing the gas to be measured into the container so that the pressure in the container becomes positive pressure;

"A substrate which is placed in its own container and adheres a chemical substance contained in the gas to be measured,

Infrared incident means for incident infrared light on the substrate,

A chemical substance detecting means for identifying the type of the chemical substance in the gas to be measured and calculating Z or the concentration of the chemical substance by analyzing infrared rays emitted after passing through the substrate;

A chemical substance detection device comprising:

8. In the chemical substance detection device according to claim 7,

There is further provided exhaust control means for controlling exhaust of the gas to be measured introduced into the container from the inside of the container.

An apparatus for detecting a chemical substance, comprising:

9. The chemical substance detection device according to claim 7 or 8, wherein the container has first and second windows made of a material that transmits infrared light. Receiving infrared light from outside the container through the first window,

The chemical substance detecting means may include an infrared ray emitted to the outside of the container through the second window after passing through the substrate, or an infrared ray reflected on the surface of the substrate and reflected from the surface of the substrate through the second window. Analyze infrared rays emitted outside

An apparatus for detecting a chemical substance, comprising:

10. The chemical substance detection device according to any one of claims 7 to 9, wherein: The chemical substance detection means identifies the type of the chemical substance in the gas to be measured and / or calculates the concentration of the chemical substance by analyzing infrared rays emitted after multiple reflection inside the substrate.

An apparatus for detecting a chemical substance, comprising:

11. The chemical substance detection device according to any one of claims 7 to 9,

The chemical substance detection unit analyzes the infrared rays that are incident from one surface side of the substrate, pass through the substrate, and are emitted from the other surface side of the substrate, and thereby analyze the infrared ray in the gas to be measured. Identify the type of chemical and / or calculate the concentration of said chemical

An apparatus for detecting a chemical substance, comprising:

12. The chemical substance detection device according to any one of claims 7 to 11, wherein:

A cooling device that cools the substrate and promotes the chemical substance in the gas to be measured to adhere to the substrate;

An apparatus for detecting a chemical substance, comprising:

1 3. In the chemical substance detection device according to claim 12,

The cooling device cools the substrate by directly contacting the substrate.

The infrared incident means is configured to input the infrared light so that a contact portion between the substrate and the cooling device is not positioned on an optical path of the infrared light.

An apparatus for detecting a chemical substance, comprising:

14. The chemical substance detection device according to any one of claims 7 to 13,

There is further provided a substrate cleaning means for removing the chemical substance attached to the substrate surface and initializing the surface state of the substrate.

An apparatus for detecting a chemical substance, comprising:

15. In the chemical substance detection device according to claim 14,

The substrate cleaning unit is configured to heat the substrate and adhere to the substrate. Heating means to remove chemicals

An apparatus for detecting a chemical substance, comprising:

16. In the chemical substance detection device according to claim 14,

The substrate cleaning unit is an ultraviolet irradiation unit that removes the chemical substance attached to the substrate by irradiating the substrate surface with ultraviolet light.

An apparatus for detecting a chemical substance, comprising: