WO2010110051A1 - Chemical substance detection apparatus - Google Patents

Abstract

Disclosed is a chemical substance detection apparatus for measuring the concentration of a chemical substance contained in a gas sample. The chemical substance detection apparatus comprises: a chamber having a gas inlet and a gas outlet; a gas introduction channel which is connected to the gas inlet and through which the gas sample is introduced into the chamber; a gas discharge channel which is connected to the gas outlet and through which the gas sample is discharged from the chamber; at least one sensor array which is arranged in the interior of the chamber and comprises a substrate and a sensor element for detecting the chemical substance and arranged on a substrate; and a signal receiving unit which can receive a signal from the sensor element.

Description

Chemical substance detection device

The present invention relates to a chemical substance detection apparatus capable of measuring the concentration of various chemical substances contained in a sample gas efficiently and accurately.

By measuring the concentration of volatile substances present in a small amount in human breath and clarifying metabolic reactions and biochemical pathological mechanisms from the increase and decrease, new biological information that has not been known so far can be hidden. Active research is being conducted to monitor invasiveness. In Japan, there are concerns about the increase in medical expenses and the collapse of the medical insurance system, and the realization of a preventive medical society is awaited. For this purpose, a system is needed that allows individuals to check their health easily and quickly. Blood, urine, sweat, saliva, exhaled air, and the like are known as biological specimens used for easily and quickly grasping an individual's health condition. Among these biological specimens, especially exhaled air contains a lot of biological information about the disease because the alveolar air and the blood in the capillaries are only separated by a very thin membrane in the body. It is known.

For example, ethane, pentane, and H ₂ O ₂ (hydrogen peroxide) in exhaled breath have a high correlation with oxidative stress. When these concentrations in exhaled air increase, symptoms such as lipid oxidation, asthma, and bronchitis appear. come. In addition, NO (nitrogen monoxide), CO (carbon monoxide) and H ₂ O ₂ in exhaled breath have a high correlation with pulmonary diseases, and as these concentrations in exhaled air increase, asthma and COPD (chronic obstructive) Symptoms of pneumonia) are observed. In addition, H ₂ (hydrogen) and carbon isotopes in exhaled air are highly correlated with gastrointestinal diseases, and when these concentrations in exhaled air increase, symptoms of dyspepsia, gastritis, and duodenal ulcer are observed. Further, acetone in exhaled breath has a high correlation with metabolic abnormalities, and when the concentration of acetone in exhaled breath increases, diabetes symptoms are observed. On the other hand, when the concentration of acetone in exhaled breath is lower than that in healthy humans, there is a tendency for metabolic syndrome.

Thus, by quantifying a specific substance contained in exhaled breath, it is possible to diagnose a disease held by the subject to some extent. In the present specification, a substance whose concentration in exhalation significantly increases or decreases in conjunction with a disease is referred to as “exhalation disease marker substance”.

In recent years, several devices have been developed that detect a disease marker substance in the breath using a device and diagnose the disease. For example, a device called NIOX MINO (registered trademark) manufactured by Aerocrine is available on the market as a device for measuring NO concentration in exhaled breath and determining the degree of asthma (aerocrine website (http://www.aerocline.com). (See Non-Patent Document 1) This is to detect asthma by detecting the NO concentration released during an asthma attack.

Japanese Patent Laid-Open No. 2004-77467 (Patent Document 1) discloses a gas that uses gas chromatography to separate a specific gas component in exhaled breath and measures the concentration of the separated gas component using a detector. An analyzer is disclosed.

JP 2004-77467 A

Aerocrine website (http://www.aerocline.com/)

In the device described in Non-Patent Document 1, there is only one type of breath disease marker substance that can be detected. On the other hand, in lung diseases other than asthma such as COPD, as in asthma, the NO concentration in exhalation tends to increase, and the quantification of one type of exhalation disease marker substance accurately indicates what kind of lung disease it is. Can not be diagnosed.

Further, the gas analyzer described in Patent Document 1 is expensive; the apparatus size is large; the temperature rise and the constant temperature of the column are essential; it has expertise in handling; and the maintenance is complicated; It is considered that personal use is impossible.

As described above, in the conventional analyzer that analyzes (quantifies) the breath disease marker substance, since the disease common to the breath disease marker substance cannot be distinguished, the subject's disease cannot be accurately diagnosed, On the other hand, when trying to increase the diagnostic accuracy, there is a problem that simplification of the apparatus and cost reduction are difficult, and it has not been possible to diagnose a disease easily and accurately.

Accordingly, an object of the present invention is to provide a chemical substance detection apparatus that can be downsized and has a relatively simple structure, and that can efficiently and accurately quantify multi-component chemical substances in a sample gas. Another object of the present invention is a chemical substance detection apparatus that can be miniaturized and has a relatively simple structure, and is capable of quantifying a plurality of exhalation disease marker substances efficiently and with high accuracy, and thus held by a subject. It is an object of the present invention to provide a chemical substance detection apparatus (disease diagnosis apparatus) for disease diagnosis that can accurately diagnose a disease.

The chemical substance detection apparatus of the present invention is a chemical substance detection apparatus for measuring the concentration of a chemical substance contained in a sample gas, and is connected to a chamber having a gas inlet and a gas outlet, and the gas inlet. A gas introduction path for introducing the sample gas into the chamber, a gas discharge path for discharging the sample gas from the chamber connected to the gas discharge port, and a chemical substance disposed in the chamber is detected 1 or 2 or more sensor arrays which arrange | position the sensor element for this on a board | substrate, and the signal receiving part for receiving the signal from a sensor element, It is characterized by the above-mentioned. The chemical substance detection apparatus of the present invention is a chemical substance detection apparatus for measuring the concentration of a plurality of chemical substances contained in a sample gas, and one or two or more sensor arrays arranged in the chamber are in total. Two or more sensor elements may be provided.

The chemical substance detection apparatus of the present invention preferably further includes a reference sensor for detecting the physical state of the specimen gas. The reference sensor is preferably installed inside the gas introduction path. The reference sensor may be a temperature sensor for detecting the temperature of the analyte gas, a humidity sensor for detecting relative humidity, or a temperature / humidity sensor for detecting temperature and / or relative humidity. The reference sensor may be a sensor for detecting the flow rate of the specimen gas. In the chemical substance detection apparatus of the present invention, preferably, the chemical substance concentration calculated based on the signal from the sensor element is appropriately corrected based on information on the physical state of the specimen gas obtained by the reference sensor. The

The chamber has a gas inlet and a gas outlet on its side surface, and at least one of the sensor arrays is preferably arranged at a position lower or higher than the gas inlet and the gas outlet.

Further, the chemical substance detection apparatus of the present invention may include two sensor arrays arranged in the chamber. In this case, it is preferable that one sensor array is disposed at a position lower than the gas inlet and the gas outlet, and the other sensor array is disposed at a position higher than the gas inlet and the gas outlet.

When the sample gas contains a chemical substance having a specific gravity smaller than that of the atmospheric gas in the chamber, one or more of the two or more sensor elements is positioned higher than the gas inlet and the gas outlet. It is preferable to arrange on the substrate of the arranged sensor array. When the specimen gas contains a chemical substance having a specific gravity greater than the atmospheric gas in the chamber, one or more of the two or more sensor elements is lower than the gas inlet and the gas outlet. Preferably, it is arranged on the substrate of the sensor array arranged in position.

In addition, the specimen gas includes two or more kinds of gaseous chemical substances having different specific gravities, and when at least one sensor array includes two or more sensor elements, the two or more sensor elements have a higher specific gravity. It is preferable that the sensor element for detecting the substance is arranged so as to be closer to the gas inlet.

The sensor element preferably includes a semiconductor sensor or a nanostructure sensor. That is, the chemical substance detection apparatus of the present invention preferably includes a semiconductor sensor or a nanostructure sensor, or both of them.

As the nanostructure sensor, a sensor comprising a carbon nanotube whose surface is modified with a carbon nanotube or a metal complex can be preferably used.

The at least one sensor array may include a sensor temperature control unit for controlling the temperature of any one or more sensor elements arranged on the substrate. The sensor temperature control unit preferably includes a heating element or a cooling element. That is, the sensor array preferably includes a heating element, a cooling element, or both. When at least one sensor array has two or more sensor elements and a cooling element, the sensor element temperature-controlled by the cooling element is closer to the gas outlet than the other sensor elements of the sensor array. It is preferable to arrange | position.

When at least one sensor array includes a sensor temperature control unit, and the sensor array includes two or more sensor elements, the sensor array further includes a heat insulating unit for thermally separating adjacent sensor elements from each other. Can do. As the heat insulating portion, a heat insulating material interposed in a substrate positioned between adjacent sensor elements, a groove formed in a substrate positioned between adjacent sensor elements, or both of these are preferably used.

Further, the chemical substance detection apparatus of the present invention can further include a gas flow rate control unit for controlling the flow rate of the sample gas flowing in the chamber. Examples of the gas flow rate control unit include a resistance tube, a permselective membrane, a mass flow controller, and a constant flow rate pump.

In the chemical substance detection apparatus of the present invention, the chemical substance concentration calculated based on the signal from any of the sensor elements is determined by the substance other than the chemical substance to be detected by the sensor element, if necessary. Correction is appropriately performed based on information on the influence of the sensor element on the signal.

The present invention also provides a chemical substance detection apparatus for measuring the concentration of a chemical substance contained in human breath, and further comprising a disease database indicating a relationship between the chemical substance concentration and a disease. provide. The chemical substance detection device is a disease diagnosis device that measures the concentration of a chemical substance (disease disease marker substance) contained in human breath and refers to a disease database from the obtained concentration value to diagnose a subject's disease. Is preferred. The chemical substance detection apparatus of the present invention preferably measures the concentration of a plurality of chemical substances contained in human breath.

The plurality of chemical substances (exhalation disease marker substances) to be measured preferably include at least NO, CO, and H ₂ O ₂ . According to the chemical substance detection apparatus (disease diagnosis apparatus) of the present invention, by measuring these concentrations, it is possible to distinguish between similar diseases belonging to the same disease, and more accurate disease determination can be performed. .

According to the present invention, it is possible to provide a chemical substance detection apparatus having a small and simple structure and capable of efficiently and accurately quantifying one or more chemical substances in a sample gas. In addition, according to the present invention, a disease diagnosis that has a small and simple structure and that can quantitate one or more types of disease marker substances in expired gas with high efficiency and high accuracy, thereby accurately diagnosing the disease. A chemical substance detection device (disease diagnosis device) can be provided.

It is a perspective view which shows typically a preferable example of the chemical substance detection apparatus of this invention. It is a perspective view which shows typically the sensor array used for the chemical substance detection apparatus of FIG. It is a top view which shows typically an example of how to arrange the sensor element arrange | positioned on the board | substrate in the chemical substance detection apparatus of this invention. It is a schematic diagram which shows an example of the semiconductor sensor which can be used as a sensor element in this invention. It is a schematic diagram which shows an example of the nanostructure sensor provided with the sensing part comprised from the carbon nanotube surface-modified with the metal complex which can be used as a sensor element in this invention. It is a perspective view showing typically an example of a sensor array provided with a sensor temperature control part. It is a perspective view which shows typically an example of a sensor array provided with a sensor temperature control part and a heat insulation part. It is a figure which shows typically an example of the whole structure of the chemical substance detection apparatus of this invention. It is a perspective view which shows typically an example of a chemical substance detection apparatus provided with a gas flow control part. 1 is a perspective view and a cross-sectional view schematically showing a chemical substance detection device manufactured in Example 1. FIG. It is a figure which shows typically the hydrogen peroxide sensor unit used in Example 1. FIG. It is a figure which shows an example of the change of resistance value when the sensor element which detects NO detects NO. FIG. 3 is a schematic diagram showing an overview of an exhalation analysis experiment in Example 1. It is the perspective view and sectional drawing which show typically the chemical substance detection apparatus produced in Example 2. FIG. It is a figure which shows the disease diagnosis apparatus of Example 3 typically. The ratio of the threshold concentration of each breath disease marker substance related to asthma, COPD, CF and lung cancer to the concentration of the breath disease marker substance in the normal state, and each breath disease marker obtained in Example 3 and Reference Example 4 It is the figure which made the radar chart the ratio of the measurement density | concentration of the substance in the human expiration | expired_air to the disease marker substance density | concentration in the expiration | expired_air in normal time.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. In addition, dimensional relationships such as length, size, and width in the drawings are changed as appropriate for clarity and simplification of the drawings, and do not represent actual dimensions.

<First Embodiment>
FIG. 1 is a perspective view schematically showing a preferred example of the chemical substance detection apparatus of the present invention. FIG. 2 is a perspective view schematically showing a sensor array 10 used in the chemical substance detection apparatus 1 of FIG. A chemical substance detection apparatus 1 shown in FIG. 1 is an apparatus for measuring concentrations of a plurality of chemical substances contained in a specimen gas in the specimen gas.

The chemical substance detection apparatus 1 shown in FIG. 1 includes a rectangular parallelepiped chamber 11 having a gas inlet 12a and a gas outlet 13a on a side surface; a hollow gas inlet path 12 connected to the gas inlet 12a; a gas outlet 13a. A hollow gas discharge path 13 connected to the sensor array 10; a sensor array 10 having a plurality of sensor elements 101 disposed in the upper and lower parts of the chamber 11; a reference sensor 14 installed in the gas introduction path 12; and A signal receiving unit (not shown in FIG. 1) for receiving a signal from each sensor element 101 is mainly configured. The sensor array 10 and the signal receiving unit are electrically connected by a conducting wire 15, and the sensor array 10 is also connected to a constant voltage power supply device (not shown) for supplying power for sensor signal measurement. Has been. The conducting wire 15 is drawn out of the chamber 11 through an opening provided on the upper and lower surfaces of the chamber 11 and having a size that allows the conducting wire 15 to pass therethrough.

Referring to FIG. 2, sensor array 10 includes a substrate 100, a plurality of sensor elements 101 disposed on one surface of substrate 100, and each sensor element 101 formed on the other surface of substrate 100. And a circuit (not shown) for transmitting a signal to the signal receiving unit.

The reference sensor 14 installed in the gas introduction path 12 is a sensor for detecting a physical state at the time of analysis of a sample gas (for example, human exhalation) to be analyzed, which is introduced into the chamber 11. In the chemical substance detection apparatus of the present embodiment, in order to accurately determine the chemical substance (measurement of the concentration in the sample gas) of the chemical substance (hereinafter also referred to as the target chemical substance) in the sample gas whose concentration is to be measured. Further, based on the detection result of the physical state of the specimen gas by the reference sensor 14, the signal from each sensor element 101 is appropriately corrected.

In the chemical substance detection apparatus 1 having the above-described configuration, the sample gas introduced into the gas introduction path 12 from the end opposite to the gas introduction port 12a side in the gas introduction path 12 is physically measured by the reference sensor 14. After the state (for example, the temperature of the sample gas, the relative humidity, etc.) is detected, it enters the chamber 11 and is discharged from the gas discharge path 13. At this time, the target chemical substance is detected by the plurality of sensor elements 101 included in the sensor array 10 disposed in the upper and lower portions of the chamber 11. The obtained detection signal of the sensor element 101 (signal change due to contact with the target chemical substance) is sent to a signal receiving unit (such as a digital multimeter) via the lead wire 15 to collect data. The data is typically stored in a computer connected to the signal receiver. The concentration of the target chemical substance in the sample gas obtained from the detection result of the sensor element 101 is more accurate based on information about the physical state of the sample gas introduced into the chamber 11 detected by the reference sensor 14. It is corrected to the density value.

Hereinafter, the chemical substance detection apparatus of the present embodiment will be described in more detail.
(Chamber, gas introduction path and gas discharge path)
The chamber is a hollow member for supporting the sensor array disposed therein and for sealing (or substantially sealing) the periphery of the sensor array (excluding the gas inlet and the gas outlet). The shape of the chamber is not particularly limited, and may be a sphere, an oblique body or the like in addition to a rectangular parallelepiped. The chamber is preferably made of a lightweight and highly durable material. Examples of such a material include resin materials such as acrylic resin and polypropylene resin.

The chamber has a gas inlet for introducing the sample gas into the chamber and a gas outlet for discharging the sample gas out of the chamber. Both the gas inlet and the gas outlet are through-holes that pass through the chamber wall that connects the chamber inner space and the chamber exterior. The positions of the gas inlet and the gas outlet are not particularly limited, but the sensor array is disposed at the upper part and / or the lower part in the chamber (for example, as shown in FIG. 1, the sensor array is located on the ceiling surface inside the chamber). And / or is preferably disposed on the side of the chamber. More preferably, the gas inlet and the gas outlet are arranged as follows.
(A) When the sensor array is arranged in the lower part of the chamber, the gas inlet and the gas outlet are arranged on the side surface of the chamber and higher than the sensor elements constituting the sensor array (that is, the sensor The array is disposed at a position lower than the gas inlet and the gas outlet).
(B) When the sensor array is disposed in the upper part of the chamber, the gas inlet and the gas outlet are disposed on the side surface of the chamber and at a position lower than the sensor elements constituting the sensor array (that is, the sensor The array is positioned higher than the gas inlet and the gas outlet).
(C) When the sensor arrays are arranged in the lower part and the upper part in the chamber, the gas inlet and the gas outlet are side surfaces of the chamber and are higher than the sensor elements constituting the lower sensor array. Is arranged at a position lower than the sensor element constituting the.

By arranging the gas inlet and the gas outlet as described above for the sensor element, the physical properties such as the specific gravity of the target chemical substance can be used to detect multiple target chemical substances efficiently and accurately. It becomes possible to do.

The positional relationship between the gas inlet and the gas outlet is not particularly limited, but a gas inlet is provided on one side of the chamber so that the sample gas can pass over all sensor elements, and the gas is provided on the side opposite to the side. It is preferable to provide a discharge port. Further, from the viewpoint of the pressure loss of the specimen gas, the gas outlet is preferably located on an extension line in the direction of the gas introduction path (the direction in which the specimen gas introduced from the gas introduction path travels).

The gas introduction path is a hollow member connected to the gas introduction port and guides the sample gas into the chamber. The gas discharge path is a hollow member connected to the gas discharge port, and discharges the sample gas after detection of the target chemical substance from the chamber to a desired position outside the chamber. The shapes of the gas introduction path and the gas discharge path are not particularly limited as long as the flow of the sample gas is not hindered, and the cross-sectional shape can be, for example, a quadrangle, a circle, an ellipse, or the like. The gas introduction path and the gas discharge path are preferably made of a light and highly durable material. Examples of such a material include resin materials such as acrylic resin and polypropylene resin.

(Sensor array and sensor element)
As described above, the sensor array transmits a signal from the substrate, a plurality of sensor elements arranged on one surface of the substrate, and each sensor element formed on the other surface of the substrate to the signal receiving unit. The circuit for this is comprised. Here, the signal from the sensor element means a signal change due to contact with the target chemical substance, for example, a change in resistance value or conductance of the entire sensor element. From this signal change, the concentration of the target chemical substance in the sample gas can be calculated. As the substrate, for example, a glass epoxy resin substrate (a substrate obtained by laminating and pressing a glass nonwoven fabric into an epoxy resin), a paper phenol substrate (paper impregnated with a phenol resin), a ceramic substrate, etc. Can be used.

The number of sensor elements provided in the chemical substance detection device is not particularly limited as long as it is 1 or more, and is determined in consideration of the number of target chemical substances to be subjected to concentration measurement. The number of sensor elements is preferably 2 or more. Usually, the same number of sensor elements as the number of target chemical substances whose concentration is to be measured are provided, and one sensor element is assigned to one target chemical substance. However, the chemical substance detection apparatus may have more sensor elements than the target chemical substance number to be measured. Such additional sensor elements may be required, for example, in separate chemical substance measurements.

The number of sensor arrays provided in the chemical substance detection apparatus is 1 or 2 or more, preferably 1 or 2. At least one sensor element is provided for one sensor array. When the chemical substance detection apparatus has one sensor array, this sensor array is preferably arranged at the upper part or the lower part in the chamber (for example, on the ceiling surface or the bottom surface inside the chamber as shown in FIG. 1). Arranged to touch). In addition, when the chemical substance detection apparatus has two sensor arrays, these sensor arrays are preferably arranged at the upper part and the lower part in the chamber (for example, as shown in FIG. Placed in contact with the ceiling and bottom). Thereby, it is possible to detect a plurality of target chemical substances efficiently and accurately using physical properties such as specific gravity of the target chemical substance. In the case where the chemical substance detection apparatus has one sensor array, it is determined in consideration of physical properties such as specific gravity of the target chemical substance whether the chemical substance detection apparatus is installed at the upper part or the lower part in the chamber.

When one sensor array is arranged in the upper part or the lower part in the chamber, the sensor array is installed so that the surface on the side having the sensor element faces the inside of the chamber. Further, when two sensor arrays are arranged at the upper part and the lower part in the chamber, these sensor arrays are similarly arranged so that the surface on the side having the sensor element faces the inside of the chamber (sensors included in each sensor array). (With the elements facing each other).

Note that it is possible to use three or more sensor arrays and divide them into, for example, an upper part and a lower part in the chamber.

Next, the arrangement of the sensor element in the chamber in consideration of the physical properties of the target chemical substance will be described. FIG. 3 is a plan view schematically showing an example of how the sensor elements arranged on the substrate in the chemical substance detection apparatus of the present invention are arranged. In the sensor array 10 shown in FIG. 3, (m × n) sensor elements 101 are installed on a substrate 100. m indicates the permutation of the sensor element 101 in the flow direction of the sample gas in the chamber (in the example shown in FIG. 3, the direction from the gas introduction path 12 to the gas discharge path 13), and n indicates the sample gas in the chamber. A permutation of the sensor elements 101 in a direction perpendicular to the flow direction is shown. m is 0, 1, 2,..., and n is 0, ± 1, ± 2,. The closer the values of m and n are to 0, the closer to the gas introduction path 12 (therefore, the gas introduction port 12a).

When the specimen gas is introduced into the chamber, the diffusion behavior of the target chemical substance contained in the specimen gas in the chamber differs depending on the physical properties such as the specific gravity of the target chemical substance. Specifically, the target chemical substance having a higher specific gravity than the atmospheric gas in the chamber in the sample gas diffuses downward (toward the bottom of the chamber) from the gas inlet, and has a lower specific gravity than the atmospheric gas in the chamber. The substance diffuses above the gas inlet (in the chamber ceiling surface direction). By arranging the sensor element in consideration of the physical properties of the target chemical substance, each target chemical substance can be detected more efficiently and accurately. An example of the atmospheric gas in the chamber is air.

More specifically, when determining the arrangement of the sensor element in the chamber, first, after selecting the target chemical substance, the specific gravity of the target chemical substance and the specific gravity of the atmospheric gas in the chamber are compared, It is divided into a group having a smaller specific gravity and a larger group than the atmospheric gas in the chamber. When a target chemical substance having a specific gravity smaller than the atmospheric gas in the chamber exists, such a substance diffuses upward (toward the chamber ceiling surface) from the gas inlet, so that the sensor array is located at the upper part in the chamber. Therefore, it is installed at a position higher than the gas inlet and the gas outlet. When a target chemical substance having a specific gravity greater than the atmospheric gas in the chamber exists, such a substance diffuses downward (toward the bottom of the chamber) from the gas inlet, so the sensor array is located in the lower part of the chamber. Therefore, it is installed at a position lower than the gas inlet and the gas outlet. When both the target chemical substance having a specific gravity smaller than the atmospheric gas in the chamber and the target chemical substance having a specific gravity larger than the atmospheric gas in the chamber are present, the above two sensor arrays are used.

Next, in each of the above groups, the specific gravity of the target chemical substance is relatively compared, and ranking is performed from the target chemical substance having the higher specific gravity. Based on this ranking, the sensor element 101 used for detecting the highest-ranked target chemical substance is disposed at the position (0, 0) in FIG. 3 (that is, the position closest to the gas introduction path). Other target chemical substances are arranged so that the higher the ranking is, the closer to the gas introduction path, and the lowest ranking chemical substance is arranged at the position closest to the gas discharge path.

In determining the arrangement of the sensor elements, the volatility of the target chemical substance may be taken into consideration. The target chemical substance having relatively high volatility diffuses deeper (that is, closer to the gas discharge path 13 in the example shown in FIG. 3), and the target chemical substance having relatively low volatility moves forward ( That is, in the example shown in FIG. 3, the sensor element that detects the target chemical substance with lower volatility is arranged closer to the gas introduction path because it diffuses closer to the gas introduction path 12. Can be considered.

(Configuration of sensor element)
As the sensor element, a semiconductor sensor, a nanostructure sensor, or the like can be used. Depending on the type of the target chemical substance, only the semiconductor sensor or the nanostructure sensor may be used, or the semiconductor sensor and the nanostructure sensor. Both of them may be used. FIG. 4 is a schematic diagram showing an example of a general semiconductor sensor that can be used as a sensor element in the present invention. The semiconductor sensor shown in FIG. 4 includes two electrodes composed of a positive electrode 104 and a negative electrode 105; a sensing unit 106 that is disposed so as to be in contact with the two electrodes and detects a target chemical substance; Sensor temperature control unit 102 located in the lower part; arranged so as to be in contact with two electrodes; an insulator 107 located between the two electrodes and the sensing unit 106 and the sensor temperature control unit 102; and a constant resistance 108 .

The sensing unit 106 is mainly made of a metal oxide and has a property of adsorbing oxygen in the air. At this time, the adsorbed oxygen traps free electrons in the sensing unit 106, and in this state, the resistance value of the entire semiconductor sensor is high. When a sensing gas containing a target chemical substance, for example, air containing CO, is brought into contact with the sensing unit 106, oxygen on the surface of the sensing unit 106 reacts with CO to become CO ₂ , which leaves the sensing unit 106. That is, oxygen on the surface of the sensing unit 106 decreases, and the trapped electrons are released, thereby reducing the resistance value of the entire semiconductor sensor. The fluctuation of the resistance value is calculated by measuring the change of the voltage V _RL at the constant resistance 108, and the presence / absence and content of the target chemical substance in the sample gas can be clarified. In a semiconductor sensor, a sensor temperature control unit 102 is usually provided in order to obtain sufficient detection sensitivity for a target chemical substance. For the insulator 107, a material having high thermal conductivity is preferably used.

The semiconductor sensor can be suitably used as a sensor element for detecting a target chemical substance such as CO, an organic gas containing carbon atoms (for example, hydrocarbon gas, alcohol, etc.), and a flammable gas such as H ₂ .

The nanostructure sensor can have the same structure as that of the semiconductor sensor except that the sensing section is composed of a nanoscale conductive material and that the sensor temperature control section and the insulator are not necessarily involved. . As the nanoscale conductive material, carbon nanofibers and the like are preferably used in addition to the carbon nanotubes described later. By using a nanoscale conductive material such as a carbon nanotube as a material constituting the sensing unit, a small, lightweight and highly sensitive sensor element at room temperature can be realized.

In a nanostructure sensor including a sensing unit composed of carbon nanotubes, the sensing unit is specifically composed of an aggregate of carbon nanotubes. When an analyte gas containing the target chemical substance is brought into contact with the sensing unit, the target chemical substance is adsorbed on the surface of the sensing unit, and thereby the resistance value of the entire nanostructure sensor changes. The fluctuation of the resistance value is calculated by measuring the change of the voltage V _RL at the constant resistance, and the presence and content of the target chemical substance in the sample gas can be clarified.

The sensing part composed of carbon nanotubes can be prepared by dispersing film-like carbon nanotubes in a solvent and then filtering them with a membrane filter or using a microwave plasma CVD apparatus on the substrate. There is a method of directly growing carbon nanotubes.

It is also effective to use a nanostructure sensor provided with a sensing part composed of carbon nanotubes whose surface is modified with a metal complex as the nanostructure sensor. By subjecting the carbon nanotube to surface modification with a metal complex, the adsorption selectivity for a specific target chemical substance can be further improved, and thereby the detection accuracy of the target chemical substance can be further improved.

FIG. 5 is a schematic diagram showing an example of a nanostructure sensor including a sensing unit composed of carbon nanotubes whose surface is modified with a metal complex, which can be used as a sensor element in the present invention. The nanostructure sensor shown in FIG. 5 includes two electrodes including a positive electrode 104 and a negative electrode 105; a sensing unit 106 that is disposed so as to be in contact with the two electrodes and that is a part for detecting a target chemical substance; It consists of a constant resistor 108. The sensing unit 106 is composed of an aggregate of carbon nanotubes whose surface is modified with a metal catalyst 109. When the analyte gas containing the target chemical substance is brought into contact with the sensing unit 106, the specific target chemical substance is selectively adsorbed on a part of the metal complex 109 of the sensing unit 106, thereby the entire nanostructure sensor. The resistance value of changes. The fluctuation of the resistance value is calculated by measuring the change of the voltage V _RL at the constant resistance 108, and the presence / absence and content of the target chemical substance in the sample gas can be clarified.

The metal complex is preferably one that selectively adsorbs a specific target chemical, for example, cobalt (II) phthalocyanine that selectively adsorbs NO; iron (II) phthalocyanine that selectively adsorbs CO; And copper (II) phthalocyanine that selectively adsorbs acetone.

A sensing part composed of carbon nanotubes surface-modified with a metal complex is prepared by attaching a metal complex to carbon nanotubes in advance, dispersing the nanotubes in a solvent, and filtering with a membrane filter or the like. And a method in which a carbon nanotube is directly grown on a substrate using a microwave plasma CVD apparatus or the like, and then a solution containing a metal complex is sprayed and applied by an inkjet or the like.

Here, as shown in FIG. 4 described above, the sensor array may include a sensor temperature control unit for controlling the temperature of any one or more sensor elements of the sensor array. Some target chemical substances such as non-volatile substances contained in the sample gas may be in a gas, liquid, or solid state depending on the sample gas temperature or the presence of other substances in the sample gas. It is considered to exist in two or more complex states. In order to accurately detect a target chemical substance such as a non-volatile substance with a sensor element, the physical state of the target chemical substance is set so that the sensor element is in a physical state that exhibits good detection accuracy. It is preferable to appropriately induce For example, when the sensor element exhibits better detection accuracy with respect to gas, it is preferable to heat the sensing unit in order to promote vaporization of a non-volatile or hardly volatile target chemical substance. As described above, when a semiconductor sensor or the like is used as the sensor element, it may be necessary to adjust the sensor element to an appropriate temperature in order to improve detection sensitivity. In addition, when the sensor element shows better detection accuracy for the liquid, it is preferable to cool the sensing unit in order to promote condensation of the non-volatile or hardly volatile target chemical substance. As described above, by providing the sensor temperature control unit, the physical state (including temperature) of the target chemical substance can be led to a physical state suitable for the sensor element that detects the target chemical substance. The accuracy can be increased, so that an accurate target chemical substance concentration can be obtained.

As described above, the sensor temperature control unit may be a heating element (for example, a heater) for heating the sensor element or a cooling element for cooling the sensor element. When the sensor array includes both a sensor element that is preferably heated and a sensor element that is preferably cooled, the sensor array may include both a heating element and a cooling element. By using a heating element and / or a cooling element as the sensor temperature control unit, the physical state of the target chemical substance is guided to a physical state suitable for the sensor element for detecting the target chemical substance by a relatively simple and inexpensive method. Thus, the detection accuracy of the sensor element can be increased.

FIG. 6 is a perspective view schematically showing an example of a sensor array provided with a sensor temperature control unit. As shown in FIG. 6, the sensor temperature control unit 102 can be provided around the pertinent sensor element 101 or around and below the sensor element 101. In such a configuration, for example, a sensor temperature control unit 102 larger than the surface of the sensor element 101 on the substrate 100 side is embedded in the surface of the substrate 100 or laminated on the substrate 100, and the sensor element is formed on the sensor temperature control unit 102. It can be obtained by installing 101. However, when using a substrate that does not have sufficient heat resistance to the heating of the sensor temperature control unit, the sensor temperature control unit and the substrate are directly connected, such as by providing a heat insulating unit between the substrate and the sensor temperature control unit. It is preferable not to touch.

As described above, referring to FIG. 3, the non-volatile or hardly volatile target chemical substance diffuses closer to the gas introduction path 12, so that the non-volatile or hardly volatile target chemical substance The sensor element having heating means (heating element) for promoting vaporization is preferably disposed at a position relatively close to the gas introduction path 12. On the other hand, the sensor element having a cooling means (cooling element) for promoting the condensation of the non-volatile or hardly volatile target chemical substance eliminates as much as possible the possibility that other target chemical substances are condensed. (More specifically, to prevent other target chemicals from condensing and consequently measuring the concentration of the target chemical low), It is preferable to arrange at a position downstream of the sensor element to be detected, that is, a position closest to the gas discharge path (gas discharge port).

Further, when the sensor array includes a sensor temperature control unit that controls the temperature of any one or more sensor elements, a heat insulating unit is provided so that the temperature control does not affect the detection accuracy of the other sensor elements. It may be. Thus, even when the sensor array includes a sensor element that requires temperature control and a sensor element that does not require temperature control, the temperature control performed on the sensor element that requires temperature control does not require temperature control. Can be eliminated, and each sensor element can maintain high detection accuracy.

FIG. 7 is a perspective view schematically showing an example of a sensor array including a sensor temperature control unit and a heat insulating unit. In the sensor array shown in FIG. 7, the temperature control by the sensor temperature control unit 102 provided in the sensor element 101- (m, n) is performed by the sensor element 101- (m ′, m having no adjacent sensor temperature control unit. A heat insulating portion 103 is provided between the sensor element 101- (m, n) and the sensor element 101- (m ′, n ′) so as not to affect the detection accuracy of n ′). Specifically, the heat insulating portion 103 provided between the sensor element 101- (m, n) and the sensor element 101- (m ′, n ′) causes the substrate 100 to be attached to the sensor element 101- (m, n). ) Are separated from the substrate on which the sensor element 101- (m ′, n ′) is formed. In addition, one of the two sensor elements separated by the heat insulating part may have a sensor temperature control part, or both may have a sensor temperature control part (for example, one of them may be heated). Element, and the other is a cooling element).

The heat insulating part is not particularly limited as long as adjacent sensor elements can be thermally separated from each other. For example, between the sensor element 101- (m, n) and the sensor element 101- (m ′, n ′). A heat insulating material such as glass wool interposed in the substrate 100 located in the substrate; and excavating the substrate 100 located between the sensor element 101- (m, n) and the sensor element 101- (m ′, n ′). The groove | channel formed by these can be mentioned. These heat insulation parts can be used alone or in combination. These heat insulating portions are preferable in that they can be formed relatively easily and inexpensively and a good heat insulating effect can be obtained.

(Reference sensor)
The reference sensor (reference sensor 14 in FIG. 1) is a sensor element for detecting the physical state of the analyte gas introduced into the chamber. In the chemical substance detection apparatus of the present embodiment, the sample introduced into the chamber, which is detected by the reference sensor, is detected by the reference sensor in the concentration of the target chemical substance in the sample gas obtained from the change in the detection signal transmitted from each sensor element. Based on information on the physical state of the gas, it is corrected to a more accurate concentration value. The physical state of the analyte gas to be detected by the reference sensor is not particularly limited, but the temperature and relative humidity of the analyte gas are particularly large in the detection signal of the sensor element (and therefore the concentration of the target chemical substance calculated therefrom). Since it has an influence, the temperature of the specimen gas, the relative humidity, and the like can be mentioned. In this case, only the temperature or relative humidity of the sample gas may be detected by the reference sensor, or both may be detected. The reference sensor may be a sensor that detects the flow rate of the specimen gas.

As a reference sensor for detecting the temperature and / or relative humidity of the specimen gas, a commercially available temperature sensor, humidity sensor, or temperature / humidity sensor can be used. As the temperature / humidity sensor, for example, a small temperature / humidity sensor “CVS-HMP-50” manufactured by CLIMATEC CORPORATION can be used. As a sensor for detecting the flow rate of the sample gas, a flow sensor such as “FD-V40” manufactured by Keyence Corporation or “FM-200” manufactured by SUNX Corporation, a carbon nanotube sensor having previously acquired data on flow characteristics, and the like can be used. .

The position where the reference sensor is installed is preferably upstream of the chamber, more preferably upstream of the chamber and in the vicinity of the gas inlet, with respect to the flow direction of the sample gas within the chemical substance detection apparatus. It is. Therefore, the reference sensor is preferably installed in the gas introduction path, and is preferably installed in the gas introduction path and in the vicinity of the gas introduction port (more preferably immediately before). By installing the reference sensor at such a position, the physical state at the time of detection of the analyte gas introduced into the chamber and detected by the sensor element can be measured more accurately.

By connecting the reference sensor to the signal receiver (such as a digital multimeter), the detection signal of the reference sensor is transmitted to the signal receiver, and this data is combined with the signal data from each sensor element of the sensor array. The data may be stored in a computer connected to the signal receiving unit. Thereby, it is possible to cause the computer to perform a correction calculation of the concentration of the target chemical substance in the sample gas obtained based on the signal data from each sensor element.

(Signal receiver)
The signal receiving unit is a part that receives a detection signal of each sensor element (which may include a reference sensor), and is connected to the sensor array by a conducting wire (the conducting wire 15 in FIG. 1). A digital multimeter is preferably used as the signal receiving unit. In this case, the detection signal data received and collected by the digital multimeter is converted from analog data to digital data. FIG. 8 is a diagram schematically showing an example of the overall configuration of the chemical substance detection apparatus of the present embodiment. As shown in FIG. 8, the chemical substance detection apparatus of this embodiment may further include a computer 20 connected to the digital multimeter 21 via the USB interface 22. The computer 20 stores digital data and performs a calculation for converting the data into a target chemical substance concentration. The computer 20 includes, for example, an interface 201 that transmits and receives data, a CPU 202 that performs calculation, and a data storage unit 203 that accumulates data (see FIG. 8). In the present embodiment, the CPU 202 can perform correction calculation of the concentration value of the target chemical substance based on information on the physical state of the specimen gas introduced into the chamber detected by the reference sensor.

(Gas flow control unit)
It is preferable that the chemical substance detection device further includes a gas flow rate control unit for controlling the flow rate of the sample gas flowing through the chamber. It is preferable that the gas flow rate control unit is capable of maintaining the flow rate of the sample gas flowing in the chamber at an arbitrary constant value. By providing such a gas flow rate control unit, the flow rate of the sample gas flowing through the chamber is kept constant, so that a stable detection signal can be obtained from the sensor element, and the detection sensitivity and detection accuracy can be improved. Even when a sensor element that depends on the flow rate is used, a stable detection signal can be obtained.

FIG. 9 is a perspective view schematically showing an example of a chemical substance detection apparatus including a gas flow rate control unit. As shown in FIG. 9, a resistance tube, a permselective membrane, a mass flow controller, a constant flow pump, and the like can be suitably used as the gas flow rate control unit.

FIG. 9A shows an example in which a resistance tube 16a is used as a gas flow rate control unit. The resistance tube 16a limits the flow rate of the analyte gas under a constant pressure by causing a pressure loss by making the diameter of the flow path smaller or longer than the gas introduction path. By connecting the resistance tube 16a in front of the gas introduction path (upstream side in the sample gas flow direction), a constant flow rate of the sample gas can be circulated in the chamber. The material of the resistance tube 16a is not particularly limited as long as the material has a poor gas adsorbability, but glass, quartz, stainless steel and the like are preferable.

FIG. 9B shows an example in which the selectively permeable membrane 16b is used as the gas flow rate control unit. By using the selectively permeable membrane 16b through which the gas constituting the atmosphere in the chamber such as the gas having the largest molecular size among the target chemical substances and the air can pass, pressure loss occurs and is the same as in the case of the resistance tube 16a. The flow rate of the sample gas under a certain pressure is limited to The material of the selectively permeable membrane 16b is not particularly limited as long as the above conditions are satisfied. The permselective membrane 16b can be installed, for example, in the gas introduction path.

FIG. 9C shows an example in which the mass flow controller 16c is used as the gas flow rate control unit. If the flow rate of the sample gas is set and inputted in advance, the mass flow controller 16c automatically monitors the flow rate of the sample gas and performs control so that the set value is obtained. The type of the mass flow controller 16c is not particularly limited, but is preferably small and portable. The mass flow controller 16c can be connected, for example, before the gas introduction path (upstream side in the sample gas flow direction).

FIG. 9D shows an example in which a constant flow pump 16d is used as the gas flow control unit. In this example, the constant flow pump 16d is equipped with a mass flow controller, and if the flow rate of the sample gas is set and inputted in advance, the pump is automatically controlled so that the sample gas flows at the set value flow rate. The flow rate of the analyte gas in the chamber can be made constant. The type of the constant flow pump 16d is not particularly limited, but is preferably small and portable. The constant flow pump 16d can be connected, for example, after the gas discharge path (downstream side in the specimen gas flow direction).

<Second Embodiment>
The chemical substance detection apparatus of the present embodiment can have the same configuration as that shown in FIG. However, in the chemical substance detection apparatus of the present embodiment, as in the first embodiment, the chemical substance detection is performed together with the correction of the concentration value of the target chemical substance based on the information on the physical state of the sample gas obtained by the reference sensor. The concentration value is corrected in consideration of the case where any one of the sensor elements provided in the apparatus has sensitivity to a substance other than the target chemical substance to be detected.

Depending on the sensor element used, it may not only be sensitive to a specific kind of chemical substance, but may also be sensitive to substances other than the target chemical substance to be detected. For example, in general metal oxide semiconductor sensors, the oxygen concentration that contributes to the reaction is largely determined by the number of carbon atoms and the structure of the chemical substance that is adsorbed. It is almost impossible to distinguish materials. When such a sensor element is used, particularly when a plurality of sensor elements exhibiting sensitivity to two or more kinds of such substances are used, the concentration of the target chemical substance targeted by each sensor element is accurately calculated. Therefore, it is preferable to analyze the data cross-sectionally using multivariate analysis and correct the results. By analyzing a plurality of target chemical substances detected by a plurality of sensor elements and their detection sensitivities, detection signals of the respective target chemical substances in each sensor element can be separated.

An example of a multivariate analysis method is multiple regression analysis. Each sensor element has a sensitivity to each substance when it is fabricated. In the present embodiment, data is collected in advance for a sensor element with low selectivity, and the influence of substances (interfering substances) other than the target chemical substance that is the detection target of the sensor element on the change in resistance value of the sensor element. . Using these data, the resistance change (signal change) is the target variable, and each concentration of the target chemical substance that brings about the resistance value of the sensor element is used as an explanatory variable, and multiple regression analysis is performed, and each substance concentration is weighted. Thus, a regression equation in each sensor element is obtained. Based on this regression equation, it is possible to derive a resistance change amount only by the target chemical substance to be detected and obtain the target chemical substance concentration corrected with high accuracy.

<Third Embodiment>
The chemical substance detection apparatus of the present embodiment measures the concentration of one or more target chemical substances contained in human breath, and shows a relationship between the concentration of the target chemical substance and the disease accumulated in advance. The present invention relates to a chemical substance detection apparatus (disease diagnostic apparatus) for diagnosing a disease by diagnosing a disease of a subject by associating a concentration of a target chemical substance with a disease of the subject with reference to a database. The chemical substance detection apparatus of the present embodiment can be basically configured in the same manner as the first or second embodiment described above. In the present embodiment, human breath is used as the sample gas in the first and second embodiments. Moreover, the target chemical substance whose concentration is measured by the chemical substance detection apparatus of the present embodiment is the above-described breath disease marker substance. According to the chemical substance detection apparatus of the present embodiment, since a plurality of breath disease marker substances can be simultaneously determined, a small and non-invasive disease diagnosis apparatus that can easily and accurately diagnose a disease is realized. Can do.

Much has already been clarified regarding the relationship between multiple exhaled breath marker substances and diseases. In the chemical substance detection apparatus of the present embodiment, a database in which the relationship between a plurality of breath disease marker substances and diseases is converted into a radar chart for each disease is stored in advance in a database unit in the computer 20 ( (See FIG. 8). Here, the database in which the relationship between a plurality of breath disease marker substances and diseases is made into a radar chart for each disease is, for example, the minimum concentration of a plurality of breath disease marker substances that can be generally determined to be the disease. The (threshold concentration) is a database or the like that is made into a radar chart for each disease and for each disease.

In the chemical substance detection apparatus (disease diagnosis apparatus) of this embodiment, preferably, the chemical substance detection apparatus is constructed using a plurality of sensor elements for detecting a plurality of breath disease marker substances corresponding to a certain disease. The The sensor element to be used may be only a sensor element for diagnosing a specific disease, or various types of detection of various types of breath disease marker substances in order to be able to diagnose a plurality of diseases. A sensor element may be mounted. When breath analysis is performed using the chemical substance detection apparatus of the present embodiment, the signal change data transmitted from each sensor element is converted into the concentration of a disease marker substance in breath, and appropriate correction is performed to perform computer 20. Is stored in the data storage unit 203 as a radar chart (conversion calculation and correction to the concentration of a disease marker substance in breath can be performed, for example, by the CPU 202 of the computer 20). The concentration chart of the respiratory disease marker substance converted into a radar chart is a disease database indicating the relationship between the concentration of the marker marker substance in the expired breath and the disease charted for each disease stored in the database unit of the computer 20 in advance. The disease with the closest pattern to be compared is assumed to be the subject's disease. Next, it is evaluated whether the subject actually has the disease (disease risk). Specifically, the concentration of a plurality of breath disease marker substances measured by a chemical substance detection device is compared with the threshold concentration of a plurality of breath disease marker substances in each disease, respectively, and the former is increased overall. If it is low as a whole, it is diagnosed as “not suffering from a disease”. In this diagnostic criterion, for example, a value greater than the threshold concentration of the breath disease marker substance is “level 5 (high disease risk)”, which is much smaller than the threshold concentration of the breath disease marker substance, The case where the process is not performed is “level 1 (no disease risk)”, and the level between these can be equally divided and displayed in a 5-level evaluation. However, this does not apply if there are corrections or improvements from a medical standpoint.

Of course, it is possible for the computer 20 to specify the disease and evaluate the risk of the disease by analyzing the radar chart pattern as described above.

Table 1 shows typical diseases, diseases classified into them, breath disease marker substances associated with the diseases, and threshold concentrations thereof.

In Table 1 above, only one exhalation disease marker substance is exemplarily shown as an exhalation disease marker substance associated with a certain disease, but a plurality of exhalation disease markers are provided for a certain disease. It is generally known that substances are associated. According to the chemical substance detection apparatus of this embodiment, the concentration of a plurality of breath disease marker substances is quantified, and based on the obtained concentration values of the plurality of breath disease marker substances, is the subject suffering from the disease? Since the diagnosis of whether or not can be performed, the diagnosis can be performed more accurately as compared with the diagnosis based on only one type of the breath disease marker substance.

Examples of combinations of breath disease marker substances quantified by the chemical substance detection apparatus of the present embodiment include combinations of NO, CO, and H ₂ O ₂ . These three types of breath disease marker substances are all associated with lung diseases such as asthma, COPD (chronic obstructive pneumonia), CF (cystic fibrosis), and lung cancer. In addition, since pentane is a breath disease marker substance associated with such a lung disease, four types of pentane added may be measured as a breath disease marker substance associated with a lung disease. In this way, by measuring a plurality of (preferably three, more preferably four) exhalation disease marker substance concentrations, it becomes possible to distinguish similar diseases belonging to the same disease, and more accurate disease determination Can be performed. According to the chemical substance detection apparatus of the present embodiment, it is possible to easily diagnose which lung disease in various lung diseases whose number of patients is increasing year by year, and the measures and medical institutions to be taken by the patient are clarified. Therefore, it becomes one of the means to delay the progression of the disease.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

<Example 1>
A chemical substance detection apparatus 2 having the following configuration, which is preferably used for measuring the concentration of the target chemical substance in human breath, was produced, and an exhalation analysis experiment was performed by the following method.

(Configuration of chemical substance detection device)
(1) Overall Configuration of Chemical Substance Detection Device FIG. 10 is a perspective view (FIG. 10 (a)) and a cross-sectional view (FIG. 10 (b)) schematically showing the chemical substance detection device 2 produced in Example 1. is there. The chemical substance detection apparatus 2 produced in the present example basically has the same configuration as the chemical substance detection apparatus shown in FIG. That is, the chemical substance detection apparatus 2 of the present embodiment includes a rectangular parallelepiped chamber 11 having a gas inlet 12a and a gas outlet 13a on the side surface; a hollow gas inlet path 12 connected to the gas inlet 12a; a gas outlet A hollow gas discharge path 13 connected to 13a; a sensor array 10a including a sensor element 101c disposed in an upper part of the chamber 11; a sensor array 10b including sensor elements 101a and 101b disposed in a lower part of the chamber 11 A reference sensor 14 installed in the gas introduction path 12; and a digital multimeter 21 (see also FIG. 8) as a signal receiving unit that receives signals from each sensor element; digital via the USB interface 22; A computer 20 connected to the multimeter 21 (see also FIG. 8); Path consists of a mass flow controller 16c as a gas flow rate control unit connected to the end opposite to the gas inlet 12a side of the 12. Conductive wires 15 connected to the back circuit of each sensor array are drawn out from openings provided on the upper and lower surfaces of the chamber 11, and the other ends of these conductive wires 15 are connected to the digital multimeter 21. . The gas inlet 12a and the gas outlet 13a are arranged on the side surface of the chamber 11 at positions higher than the sensor elements 101a and 101b included in the lower sensor array 10b and lower than the sensor elements 101c included in the upper sensor array 10a. Has been. Further, the gas discharge port 13 a is located on an extension line in the path direction of the gas introduction path 12.

The outer shape of the chamber 11 is 5 cm long × 5 cm wide × 8 cm high. The chamber 11, the gas introduction path 12, and the gas discharge path 13 are each made of acrylic resin. Further, as the substrate of each sensor array, a glass epoxy resin substrate (a substrate obtained by laminating and pressing a glass nonwoven fabric into an epoxy resin) was used. A copper pattern is formed on the surface of the substrate where the sensor element is installed.

The chemical substance detection apparatus 2 is a chemical substance detection apparatus that detects NO, CO, and H ₂ O ₂ as target chemical substances.

(2) Arrangement of Sensor Element The sensor element 101c included in the sensor array 10a installed in the upper part of the chamber 11 is a sensor element for detecting CO. The sensor element 101 c is provided with a platinum heater as the sensor temperature control unit 102. The sensor elements 101a and 101b included in the sensor array 10b installed in the lower part of the chamber 11 are sensor elements for detecting NO and H ₂ O ₂ , respectively. In the sensor array 10b, the sensor elements 101a and 101b are arranged immediately below the straight line connecting the gas inlet 12a and the gas outlet 13a, and the sensor element 101a for detecting NO is closer to the gas inlet 12a. The sensor element 101b for detecting H ₂ O ₂ is arranged closer to the gas outlet 13a. The arrangement of the three types of sensor elements was determined in consideration of the specific gravity of the target chemical substance with respect to air, which is the atmospheric gas in the chamber. Table 2 shows specific gravity and the like of NO, CO, and H ₂ O ₂ with respect to air. The pentane in Table 2 will be described later.

As can be seen from Table 2, since H ₂ O ₂ is hardly volatile and is preferably detected as a liquid, the sensor element 101b that detects H ₂ O ₂ is the most gas exhausted sensor array 10b. It was arranged at a position close to the path 13. Further, when NO, CO, and air are arranged in descending order of specific gravity, NO> air (specific gravity 1)> CO, so that sensor element 101c that detects CO on the upper surface of chamber 11 as shown in FIG. , A sensor element 101a for detecting NO on the bottom surface of the chamber 11, and a sensor element 101a for detecting NO and a sensor element 101b for detecting H ₂ O ₂ in order from the side closer to the gas introduction path 12. It arranged so that it might become. The reason why the platinum heater as the sensor temperature control unit 102 is provided in the gas sensor element 101c for detecting CO is to obtain sufficient detection sensitivity for CO.

(3) Sensor element for detecting NO Since it has been verified that NO is selectively adsorbed to Co in cobalt (II) phthalocyanine (hereinafter referred to as CoPc), the sensor element 101a for detecting NO has CoPc. A nanostructure sensor with a sensing part composed of surface-modified carbon nanotubes was selected. The manufacturing procedure of the sensor element 101a for detecting NO is as follows.

First, 1.4 mg of CoPc powder (manufactured by Wako Pure Chemical Industries, Ltd.) was weighed and placed in a sample bottle, and 50 mL of tetrahydrofuran (hereinafter referred to as THF) was added and sufficiently dissolved to prepare a CoPc 0.05 mM standard solution. Next, 2 mg of single-walled carbon nanotubes (hereinafter SWCNT; manufactured by Honjo Chemical) are weighed and put into a sample bottle, 5 mL of CoPc 0.05 mM standard solution is added, and ultrasonic dispersion is performed for 30 minutes. This is used as a membrane filter. And recovered by filtration. Put this filter in another sample bottle, add 5 mL of CoPc 0.05 mM standard solution to peel off SWCNT, collect the membrane filter, and then ultrasonically disperse again for 30 minutes. It was collected. The same operation was performed once again, and surface modification was performed three times in total. The SWCNT collection membrane filter was placed in a sample bottle, 50 mL of ethanol was added to peel off the SWCNT, and after collecting the membrane filter, ultrasonic dispersion was performed for 30 minutes to prepare a CoPc surface-modified SWCNT dispersion. Next, 2 mL of this CoPc surface-modified SWCNT dispersion is weighed out, filtered through a membrane filter, attached to a sensor array substrate with double-sided tape, and then the copper pattern on the substrate from each end of the sensing unit made of CoPc surface-modified SWCNT. A positive electrode and a negative electrode were produced with a silver paste toward the surface to obtain a sensor element 101a for detecting NO.

(4) Sensor element for detecting CO Since it has been verified that CO selectively adsorbs to Fe in iron (II) phthalocyanine (hereinafter referred to as FePc), the sensor element 101c for detecting CO includes iron (II II) A nanostructure sensor comprising a sensing part consisting of carbon nanotubes surface-modified with phthalocyanine was selected. The manufacturing procedure of the sensor element 101c for detecting CO was the same as that for the sensor element 101a for detecting NO except that FePc powder (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of CoPc.

(5) The sensor element 101b for detecting the sensor element H ₂ O ₂ for detecting the H ₂ O _2, in order to increase the detection accuracy of the H ₂ O _2, the sample gas is almost gaseous state cooling, condensation, A hydrogen peroxide sensor unit having a cooling function comprising a manganese dioxide-immobilized film and a dissolved oxygen sensor capable of detecting H ₂ O ₂ in a liquid state was selected.

FIG. 11 is a diagram schematically showing the hydrogen peroxide sensor unit (sensor element 101b). FIG. 11A is an overall view of the hydrogen peroxide sensor unit. Moreover, FIG.11 (b) is sectional drawing of the exclusive holder used for a hydrogen peroxide sensor unit, and FIG.11 (c) is a perspective view of an exclusive holder.

Referring to FIG. 11, a hydrogen peroxide sensor unit (sensor element 101b) was produced by the following procedure. First, the manganese dioxide fixed film | membrane 61 was produced by melt | dissolving polyvinyl chloride in nitrophenyl octyl ether, adding manganese dioxide powder, and making it dry. Further, a dissolved oxygen sensor 70 composed of an electrolytic solution 67 made of an aqueous potassium chloride solution, a Pt electrode 65 and an Ag electrode 66 immersed in the electrolytic solution 67, and an ammeter 68 for measuring a current value between the electrodes. Prepared. Next, the dissolved oxygen sensor 70 and the manganese dioxide immobilization film 61 were fixed by a dedicated holder 60 having a metal part 62 so that the Teflon (registered trademark) film as the oxygen selective permeable film 64 was sandwiched therebetween. . Moreover, it installed so that the Peltier device 63 might closely_contact | adhere to the exclusive holder 60. FIG. The dedicated holder 60 includes a metal part 62 on the side in contact with the sample gas, and the surface of the metal part 62 on the sample gas contact side is inclined toward the cavity part of the dedicated holder 60.

In the hydrogen peroxide sensor unit (sensor element 101b) having the above configuration, when the sample gas comes into contact with the inclined surface of the metal part 62 cooled by the Peltier element 63, the sample gas condensate 71 is generated on the inclined surface. When this condensate exceeds a certain size, it flows to the manganese dioxide-immobilized film 61 due to its weight, and H ₂ O ₂ in the specimen gas condensate 71 is dispersed in the manganese dioxide-immobilized film 61. Reduced by the catalytic action of manganese, oxygen is generated. The generated oxygen passes through the oxygen selective permeable membrane 64 and is detected by the dissolved oxygen sensor 70. The oxygen concentration can be obtained by measuring the current value indicated by the ammeter 68, and the H ₂ O ₂ concentration in the sample gas can be known from the obtained oxygen concentration value.

(6) Reference sensor, mass flow controller, and digital multimeter A small temperature / humidity sensor (manufactured by Klimatec Co., Ltd.) was used as the reference sensor 14. A mass flow controller (manufactured by Cofrock) was used as the mass flow controller 16c as the gas flow rate control unit. Further, a digital multimeter (manufactured by Agilent) was used as the digital multimeter 21 as the signal receiving unit. A computer 20 is connected to the digital multimeter 21 via a USB interface 22. As shown in FIG. 8, the computer 20 includes an interface 201 that transmits and receives data, a CPU 202 that performs calculation, and a data storage unit 203 that stores data.

(Calculation of target chemical substance concentration based on signal change of each sensor element)
The signal change transmitted from each sensor element (for the sensor elements 101a and 101c, the change in the resistance value of the entire sensor element, and for the sensor element 101b, the change in the current value indicated by the ammeter 68), In order to convert the concentration of the target chemical substance in the sample gas, prior to the breath analysis experiment, signal changes at various target chemical substance concentrations are measured for each sensor element in advance. A relational expression (calibration curve) between the concentration of the target chemical substance detected by the element and the characteristic value y of the sensor element was prepared. Here, the characteristic value y is expressed by the following formula (1).

y (%) = (conductance when detecting target chemical substance−conductance immediately before detecting target chemical substance) / (conductance immediately before detecting target chemical substance) × 100 (1)
However, in the sensor element 101 b that detects H ₂ O ₂ , the conductance in the above formula (1) is a current value indicated by the ammeter 68. The characteristic value y of the sensor element is uniquely determined by the kind and amount of the sensing portion constituent material and the surface modifying substance and the arrangement of the electrodes when the sensor element is manufactured.

As an example of a data profile indicating the relationship between the resistance value used when determining the characteristic value y of the sensor element and the target chemical substance concentration, FIG. 12 shows the resistance value when the sensor element 101a that detects NO detects NO. An example of the change is shown. In FIG. 12, the horizontal axis represents elapsed time (sec), and the vertical axis represents resistance value (kΩ). Up to A in FIG. 12, a test gas not containing NO is supplied, the supplied gas is switched to a test gas containing NO at time A, and further, the test gas containing NO is switched again at time B. It was. As shown in FIG. 12, it can be seen that when the sensor element detects NO, the resistance value increases and reaches a certain value. This constant value was obtained for various NO concentrations, and a relational expression (calibration curve) between the NO concentration and the characteristic value y of the sensor element was created. The same applies to other sensor elements. In preparing a calibration curve, the test gas is assumed to be a sample gas of human breath, and is a mixed gas composed of 79% N ₂ , 16% O ₂ and 5% CO ₂ (substantially the same as air). The composition and relative humidity were 0).

Tables 3 to 5 show characteristic values y of the sensor elements at various target chemical substance concentrations measured by the above method. Table 3 shows the results for the sensor element 101a that detects NO, Table 4 shows the results for the sensor element 101c that detects CO, and Table 5 shows the results for the sensor element 101b that detects H ₂ O _2. . The flow rate of the test gas was 500 ml / min.

Based on the data in Tables 3 to 5, the concentration x (unit: ppb) of the target chemical substance contained in the test gas represented by the following formulas (2) to (4) and the sensor element using the least square method. A linear approximation relation (calibration curve) with the characteristic value y (unit:%) was obtained.

[Sensor element 101a for detecting NO]
y _NO = −0.06215x _NO (2)
(Where x _NO represents the concentration of NO contained in the sample gas, that is, the volume of NO / (volume of NO + volume of test gas) [ppb], and y _NO represents the sensor element 101a that detects NO. The characteristic value [%] at the NO concentration of N. (The same applies to the following equations (3) and (4).)
[Sensor element 101c for detecting CO]
y _CO = 0.01332x _CO (3)
[Sensor element 101b for detecting H ₂ O ₂ ]
y _H2O2 = 0.01008x _H2O2 (4)
From the relational expressions (2) to (4), it is possible to calculate the concentration of each target chemical substance from the signal change of each sensor element. In the present embodiment, the target chemical substance concentration is obtained by the single regression analysis as described above (that is, the characteristic value y is expressed using one variable x).

(Correction based on sample gas humidity data)
In the quantification of the target chemical substance using the chemical substance detection apparatus of the present embodiment, in order to further improve the accuracy of the obtained target chemical substance concentration, the target chemical substance concentration x obtained from the above equation is used as the reference sensor 14. Correct the detection based on the detected data. Specifically, before the breath analysis experiment, for each of the sensor element 101a for detecting NO and the sensor element 101c for detecting CO, the characteristic value changes in the relative humidity of various specimen gases are measured. A relational expression (calibration curve) between the characteristic value y and the relative humidity in the sensor element was created. The results are shown in Table 6 and Table 7. In preparing the calibration curve, the test gas was a mixed gas composed of 79% N ₂ , 16% O ₂ and 5% CO ₂ (however, the moisture indicating the relative humidity shown in Tables 6 and 7 was used). Contained).

Table 6 shows characteristic values when the relative humidity (%) in the sample gas is variously changed in the sensor element 101a that detects NO. The NO concentration in the sample gas (that is, NO volume / (NO volume + test gas volume) [ppb]) was fixed at 100 ppb for measurement. Table 7 shows characteristic values when the relative humidity (%) in the sample gas is variously changed in the sensor element 101c for detecting CO. The CO concentration in the sample gas (that is, the volume of CO / (volume of CO + volume of test gas) [ppb]) was measured at a fixed 500 ppb. For the sensor element 101b for detecting H ₂ O ₂ , the sample gas was detected in a liquid state, and most of the liquid was moisture, and thus was not included in the correction by the relative humidity data of the sample gas. .

Based on the data in Tables 6 and 7, using the least square method, the relative humidity RH (unit:%) of the sample gas and the sensor element characteristic value y (unit) represented by the following formulas (5) and (6) :), a linear approximation relational expression (calibration curve) was obtained.

[Sensor element 101a for detecting NO]
y ′ _NO = y _{NO, RH = 0} −0.0901 _RH (5)
(In the formula, RH represents the relative humidity [%] of the sample gas (test gas + water + NO). Y ′ _NO is a sensor element that detects NO when the relative humidity of the sample gas is RH [%]. The characteristic value [%] of 101a is shown _{, and yNO, RH = 0} shows the characteristic value [%] when the relative humidity is 0% (the same applies to the following formula (6)).
[Sensor element 101c for detecting CO]
y ′ _CO = y _{CO, RH = 0} −0.019556RH (6)
Therefore, the relative humidity RH of the sample gas obtained from the reference sensor 14 (%) by substituting the RH of the formula (5), by substituting the characteristic values measured in breath analysis experiment y _'NO, relative humidity The characteristic value y _{NO, RH =} 0 in the case where is ₀ is calculated and substituted for y _NO in the above equation (2), the characteristic value due to the moisture contained in the sample gas is eliminated, It is possible to obtain a NO concentration that takes into account only the characteristic values that are purely attributable to NO. The same applies to CO.

(Expiration analysis experiment using chemical substance detection equipment)
FIG. 13 is a schematic diagram showing an outline of the breath analysis experiment. Hereinafter, the breath analysis experiment conducted in this example will be described with reference to FIG. First, as shown in FIG. 13A, a 1 L capacity washed Tedlar bag 30 having two switching valves, an A valve 301 and a B valve 302, was prepared. Then, the mouthpiece 31 was installed on the A valve 301, the A valve 301 was opened, and the B valve 302 was closed. After the person who was the subject inhaled a large amount of breath, stopped for 10 seconds, exhaled for 10 seconds, added the mouthpiece, collected the remaining human exhalation in the Tedlar bag 30, and immediately turned off the A valve 301. Closed. Next, as shown in FIG. 13B, 100 mL of exhalation was collected from the B valve 302 using the gas tight syringe 32.

Next, as shown in FIG. 13 (c), the tip needle of the gas tight syringe 32 is inserted into the inlet of the mass flow controller 16 c installed at the end of the gas introduction path 12, and a substantially constant load is applied to the gas tight syringe 32. Then, human exhalation was introduced into the chamber 11 from the gas introduction path 12, and the relative humidity data of the human exhalation was acquired by the reference sensor 14, and the signal change from each sensor element was acquired. Signal data from each sensor element was stored in the computer 20. From the obtained data, using the above equations (2) to (6), the NO and CO concentrations in human breath corrected by the relative humidity data, and the H ₂ O ₂ concentration were calculated.

<Reference Example 1>
Except that the reference sensor 14 is not installed, the chemical substance detection device is constructed in the same manner as in Example 1, and the correction by the relative humidity data of human breath is not performed. Thus, NO, CO and H ₂ O ₂ concentrations were calculated.

<Reference Example 2>
In order to evaluate the accuracy of each target chemical substance concentration obtained in Example 1 and Comparative Example 1, the actual NO concentration, CO concentration, and H ₂ O ₂ concentration in human breath in the Tedlar bag 30 were respectively determined. It quantified using the following apparatus.
NO concentration: NO concentration measuring device manufactured by Nippon Thermo,
CO concentration: GC-FID manufactured by Shimadzu Corporation
H ₂ O ₂ concentration: HPLC + ECD manufactured by GL Sciences.

Measured characteristic values of the sensor element for NO (sensor element 101a), the sensor element for CO (sensor element 101c), and the sensor element for H ₂ O ₂ (sensor element 101b) of Example 1 and Reference Example 1, and the reference sensor Table 8 shows the relative humidity (only Example 1) of human breath obtained from No. 14. Table 9 shows the concentrations of NO, CO and H ₂ O ₂ in human exhalation calculated from the measured characteristic values shown in Table 8 based on the above formulas (2) to (4) ( Example 1). Table 9 also shows actual concentrations of NO, CO, and H ₂ O ₂ measured in Reference Example 2 above. Here, the concentrations of NO and CO of Example 1 shown in Table 9 are calculated from the measured characteristic values and relative humidity shown in Table 8 by the above formulas (2), (3), (5) and (6). ) And is a corrected concentration that excludes the influence of moisture in human breath. On the other hand, the concentrations of NO and CO in Reference Example 1 were calculated based on the above formulas (2) and (3) only from the actually measured characteristic values shown in Table 8, and the moisture in the human breath The effect on the characteristic value is not considered.

As is clear from the results shown in Table 9, the characteristic values of sensor elements other than the sensor element for H ₂ O ₂ are greatly affected by moisture in the exhalation. Refer to the influence of such moisture. It can be seen that an extremely accurate target chemical substance concentration can be obtained by appropriately eliminating and correcting the characteristic value based on the data obtained by the sensor.

Here, Table 10 shows characteristic values and characteristic value calibration constants k _NO (reference flow rate of 500 ml) when the flow rate (ml / min) of the sample gas (test gas) in the sensor element 101a for detecting NO is variously changed. / Min is a coefficient for correcting the deviation of the specific value y at each flow rate when the flow rate is / min, and the characteristic value at each flow rate is divided by the characteristic value at the reference flow rate). The NO concentration in the sample gas (that is, the volume of NO / (volume of NO + volume of test gas) [ppb]) was measured at a fixed 50 ppb.

Based on the data of Table 10, the use of the least squares method, the flow rate u (unit: ml / min) of the sample gas relationship between the characteristic value calibration factor k _NO sensor element is approximated by the following formula .

k _NO = 0.00014u + 0.92435
The basic characteristics of all sensors are measured at this reference flow rate. Even when the sample gas is introduced at a flow rate other than the reference flow rate, the characteristic value at the reference flow rate can be corrected by applying a calibration coefficient to the obtained characteristic value. Such correction of the flow rate of the sample gas is effective when the chemical substance detection device does not have a gas flow rate control unit or when the flow rate of the sample gas is too small to ensure the reference flow rate.

Table 10 shows the case of the sensor element 101a that detects NO. However, since the flow rate characteristic varies depending on the type of sensor element, the above relational expression is provided for each sensor element as in the case of the correction based on the relative humidity described above. Ask for. Further, since the flow rate characteristic varies depending on the target chemical substance concentration in the sample gas, it is preferable to obtain the above relational expression for each concentration.

<Example 2>
A chemical substance detection apparatus 3 having the following configuration, which is preferably used for measuring the concentration of the target chemical substance in human exhalation, was prepared, and an exhalation analysis experiment was performed by the following method.

(Configuration of chemical substance detection device)
(1) Overall Configuration of Chemical Substance Detection Device FIG. 14 is a perspective view (FIG. 14 (a)) and a cross-sectional view (FIG. 14 (b)) schematically showing the chemical substance detection device 3 produced in Example 2. is there. In the chemical substance detection apparatus 3 manufactured in the present embodiment, the sensor array 10a disposed in the upper part of the chamber 11 includes a sensor element 101d for detecting pentane in addition to the sensor element 101c for detecting CO. Except for further provision, it is basically the same as the chemical substance detection apparatus 2 of the first embodiment. That is, the chemical substance detection device 3 is a chemical substance detection device that detects NO, CO, H ₂ O ₂ and pentane as target chemical substances.

(2) Arrangement of sensor elements The sensor element 101c provided in the sensor array 10a installed in the upper part of the chamber 11 is a sensor element for detecting CO, and the sensor element 101d is a sensor element for detecting pentane. It is. The sensor element 101 c is provided with a platinum heater as the sensor temperature control unit 102. The sensor elements 101a and 101b included in the sensor array 10b installed in the lower part of the chamber 11 are sensor elements for detecting NO and H ₂ O ₂ , respectively. In the sensor array 10a, the sensor elements 101c and 101d are arranged immediately above the straight line connecting the gas inlet 12a and the gas outlet 13a, and the sensor element 101c for detecting CO is closer to the gas inlet 12a. The sensor element 101d for detecting pentane is arranged closer to the gas exhaust port 13a. Similarly, in the sensor array 10b, the sensor elements 101a and 101b are arranged immediately below a straight line connecting the gas inlet 12a and the gas outlet 13a, and the sensor element 101a for detecting NO is more gas inlet 12a. The sensor element 101b for detecting H ₂ O ₂ is disposed closer to the gas exhaust port 13a. The arrangement of the four types of sensor elements is determined in consideration of the specific gravity of the target chemical substance with respect to the air, which is the atmospheric gas in the chamber. As shown in Table 2 above, when pentane, CO, and air are arranged in descending order of specific gravity, air (specific gravity 1)>CO> pentane, so that the sensor element 101d that detects pentane is an upper sensor array. In addition, the specific gravity is smaller than that of CO, and is easily transported farther. Therefore, the sensor element 101c that detects CO is disposed downstream (closer to the gas discharge path 13). In the upper sensor array 10a, the heat insulating portion 103 is provided on the substrate located between the sensor element 101c and the sensor element 101d so that the heating of the platinum heater provided in the sensor element 101c does not adversely affect the sensor element 101d. As a result, a rectangular groove having a width of 5 mm and a depth of 5 mm was formed.

(3) Sensor element for detecting NO The sensor element 101a for detecting NO used in the chemical substance detection apparatus 3 of this example is a carbon nanotube whose surface is modified by CoPc used in the chemical substance detection apparatus 2 of Example 1. It is the same sensor element as a nanostructure sensor provided with the sensing part which consists of.

(4) Sensor element for detecting CO In this example, a semiconductor sensor having the structure shown in FIG. 4 as the sensor element 101c for detecting CO and using tin oxide as the metal oxide constituting the sensing unit is used. Using.

(5) sensor element 101b for detecting the H ₂ O ₂ used in the chemical detection device 3 of the sensor element present embodiment for detecting the H ₂ O ₂ is peroxide used in the chemical sensor device 2 in Example 1 It is the same sensor element as the hydrogen sensor unit.

(6) Sensor element for detecting pentane Since it has been verified that pentane adsorbs to Cu in Cu (II) phthalocyanine (hereinafter referred to as CuPc), the sensor element 101d for detecting pentane includes Cu (II) phthalocyanine. A nanostructure sensor with a sensing part consisting of carbon nanotubes surface modified by was selected. The production procedure of the sensor element 101d for detecting pentane was the same as the sensor element for detecting NO used in Example 1, except that CuPc powder (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of CoPc.

(7) Reference sensor, mass flow controller, and digital multimeter The reference sensor 14, the mass flow controller 16c, and the digital multimeter 21 are the same as those in the first embodiment. A computer 20 is connected to the digital multimeter 21 via a USB interface 22. As shown in FIG. 8, the computer 20 includes an interface 201 that transmits and receives data, a CPU 202 that performs calculation, and a data storage unit 203 that stores data.

(Calculation of target chemical substance concentration based on signal change of each sensor element)
Change in signal transmitted from each sensor element (for sensor elements 101a, 101c, and 101d, it is a change in the resistance value of the entire sensor element, and for sensor element 101b, it is a change in the current value indicated by ammeter 68) In order to convert the target chemical substance into the concentration in the sample gas, in the same manner as in Example 1, before the breath analysis experiment, signal changes at various target chemical substance concentrations are measured for each sensor element in advance. Thus, a relational expression (calibration curve) between the concentration of the target chemical substance detected by the sensor element and the characteristic value y of the sensor element in each sensor element was created.

In preparing the calibration curve, a mixed gas composed of 79% N ₂ , 16% O ₂ and 5% CO ₂ (relative humidity is 0) was used as the test gas, as in Example 1. The flow rate of the test gas was 500 ml / min.

Tables 11 and 12 respectively show sensor element characteristic values y at various target chemical substance concentrations measured by the above method for sensor element 101c for detecting CO and sensor element 101d for detecting pentane.

Based on the data in Tables 11 and 12 above, using the least square method, the concentration x (unit: ppb) of the target chemical substance contained in the test gas represented by the following formulas (7) and (8) and the sensor element A linear approximation relation (calibration curve) with the characteristic value y (unit:%) was obtained.

[Sensor element 101c for detecting CO]
y _CO = −0.010498x _CO (7)
(Wherein x _CO represents the concentration of CO contained in the sample gas, that is, the volume of CO / (volume of CO + volume of test gas) [ppb], and y _CO represents sensor element 101c for detecting CO. Is the characteristic value [%] at the CO concentration, and the same applies to (8) below.)
[Sensor element 101d for detecting pentane]
y _pentane = -0.014897x _pentane (8)
For the sensor element 101a for detecting NO and the sensor element 101b for detecting H ₂ O ₂ , the above formulas (2) and (4) were also used in this example.

(Correction based on sample gas humidity data)
In order to further improve the accuracy of the obtained target chemical substance concentration, the target chemical substance concentration is fixed for the sensor element 101c for detecting CO and the sensor element 101d for detecting pentane in the same manner as in Example 1. A relational expression (calibration curve) between the value y and the relative humidity of the sample gas was prepared. The results are shown in Table 13 and Table 14. In preparing a calibration curve, the test gas is a mixed gas composed of 79% N ₂ , 16% O ₂ and 5% CO ₂ (however, the moisture indicating the relative humidity shown in Tables 13 and 14 is used). Contained).

Based on the data in Tables 13 and 14, the relative humidity RH (unit:%) of the sample gas and the sensor element characteristic value y (unit) represented by the following formulas (9) and (10) using the least square method: :), a linear approximation relational expression (calibration curve) was obtained.

[Sensor element 101c for detecting CO]
y ′ _CO = y _{CO, RH = 0} −0.008895RH (9)
(In the formula, RH represents the relative humidity [%] of the sample gas (test gas + water + CO). Y ′ _CO is a sensor element that detects CO when the relative humidity of the sample gas is RH [%]. The characteristic value [%] of 101c is indicated, and y _{CO, RH = 0} indicates the characteristic value [%] when the relative humidity is 0. The same applies to the following formula (10).
[Sensor element 101d for detecting pentane]
y ' _pentane = y _{pentane, RH = 0} -0.02204RH (10)
For the sensor element 101a for detecting NO, the above formula (5) is also used in this embodiment.

(Correction of target chemical concentration by multivariate analysis)
The sensor element 101a for detecting NO and the sensor element 101b for detecting H ₂ O ₂ that are used in the present embodiment are selectively sensitive to NO and H ₂ O ₂ , respectively, and are sensitive to other substances. Not shown. On the other hand, the sensor element 101c for detecting CO in this embodiment also shows sensitivity to pentane, and the sensor element 101d for detecting pentane shows somewhat sensitivity to CO. That is, these two sensor elements also exhibit characteristic values for gases other than the target chemical substance (interfering gas). Therefore, when using a plurality of sensor elements that exhibit sensitivity to two or more kinds of such substances, in order to accurately calculate the concentration of the target chemical substance targeted by each sensor element, multivariate analysis is used. It is preferable to analyze the data across the board and correct the result. In this example, correction was made by multiple regression analysis. Details are as follows.

Tables 15 and 16 show characteristic values of the sensor element 101d for detecting pentane and the sensor element 101c for detecting CO at a relative humidity of 0% with respect to a mixed gas of pentane and CO having various concentrations. Indicated. Table 15 shows the raw data obtained from the actual measurement values as they are, and Table 16 shows data obtained when these data are standardized. Standardization means normalization by dividing a data value and the average of the data collection by the variance of the data collection. Usually implemented when the units between are different. When multiple regression analysis was performed on the data in Table 16, regression equations represented by the following formulas (11) and (12) were obtained.

[Sensor element 101c for detecting CO]
y ″ _CO = −8.4574x _CO −28.4427x _pentane (11)
(Wherein, y '' _CO is the sensor element 101c for detecting the CO, is a characteristic value including the influence of interfering gases (pentane) in RH = 0%, x _CO, respectively x _pentane, the sample gas (Concentrations of CO and pentane contained. These are all values after standardization. The same applies to the following formula (12).)
[Sensor element 101d for detecting pentane]
y ″ _pentane = −5.3349747 × _CO −64.8568 × _pentane (12)
Therefore, the relative humidity RH (%) of the sample gas obtained from the reference sensor 14 is substituted for RH in the above equation (9), and the characteristic value of the sensor element 101c for detecting CO measured in the breath analysis experiment is expressed by y by substituting the _'CO, characteristic values y _CO when the relative humidity is _0, calculates the _{RH = 0,} also the relative humidity RH of the sample gas obtained from the reference sensor 14 (%) of the above formula (10 ) And the characteristic value y _{pentane, RH} when the relative humidity is 0 by substituting the characteristic value of the sensor element 101d for detecting pentane actually measured in the breath analysis experiment into y ′ _pentane in the same equation. _{= 0} , and substituting them into y ″ _{CO 2} and y ″ _pentane in the above equations (11) and (12), respectively, and solving the equations, the moisture and interfering gas contained in the sample gas Caused characteristic values are eliminated The exact CO concentration and pentane concentrations can be obtained. Note that the calculation of the NO concentration and the H ₂ O ₂ concentration is the same as in Example 1.

The degree-of-freedom adjusted determination coefficients representing the fitting of the regression equations (11) and (12) with the actual measurement values are 0.888 for the sensor element 101c and 0.887 for the sensor element 101d. And have a very good correlation.

In this example, since the regression equations (11) and (12) are used for calculating the CO concentration and the pentane concentration, the above equations (7) and (8) are not used.

(Expiration analysis experiment using chemical substance detection equipment)
The same breath analysis experiment as in Example 1 was performed, and the concentrations of NO, CO, H ₂ O ₂ and pentane were calculated using the above formulas (2), (4), (5) and (9) to (12). did.

<Reference Example 3>
The calculation of the CO concentration and the pentane concentration does not use the regression equations (11) and (12), but uses the above equations (7) and (8) (that is, interference with the characteristic values of the sensor elements 101c and 101d). NO, CO, H ₂ O ₂ and pentane concentrations were calculated in the same manner as in Example 2 except that the influence of gas was not taken into consideration.

<Reference Example 4>
In order to evaluate the accuracy of each target chemical substance concentration obtained in Example 2 and Reference Example 3, the actual NO concentration, CO concentration, H ₂ O ₂ concentration and pentane concentration in the human breath in the Tedlar bag 30 Were quantified using the following apparatuses.
NO concentration: NO concentration measuring device manufactured by Nippon Thermo,
CO concentration: GC-FID manufactured by Shimadzu Corporation
H ₂ O ₂ concentration: HPLC + ECD manufactured by GL Science
Pentane concentration: GC-MS manufactured by JEOL.

Example 2 and Reference Example 3 NO sensor element (sensor element 101a), CO sensor element (sensor element 101c), H ₂ O ₂ sensor element (sensor element 101b), and pentane sensor element (sensor element 101d) Table 17 shows the actually measured characteristic values and the relative humidity of human breath obtained from the reference sensor 14. These measured data are common to Example 2 and Reference Example 3.

Further, Table 18 shows NO, CO calculated from the measured characteristic values shown in Table 17 based on the above formulas (2), (4), (5), (9) to (12). , H ₂ O ₂ and pentane concentrations in human breath are shown (Example 2). Table 18 also shows actual concentrations of NO, CO, H ₂ O ₂ and pentane measured in Reference Examples 3 and 4 above. As shown in Table 18, when the low selectivity of the sensor element is not considered and the resistance value change in the sensor element 101c and the sensor element 101d is regarded as a change caused by a single chemical substance and data processing is performed, It can be seen that it is difficult to obtain a more accurate concentration.

<Example 3>
A chemical substance detection apparatus (disease diagnostic apparatus) for quantifying a plurality of exhalation disease marker substances in human exhalation was constructed, and an experiment for diagnosing a disease using the same human exhalation as in Example 2 was performed.

(Configuration of disease diagnosis device)
FIG. 15 is a diagram schematically illustrating a disease diagnosis apparatus according to the present embodiment. The disease diagnosis apparatus has substantially the same configuration as that of the chemical substance detection apparatus 3 of the second embodiment, but the computer 20 has a database unit 204 for storing a database (configuration of the computer 20). (See FIG. 15 (b) showing in more detail), the database unit 204 is characterized in that a database in which the relationship between a plurality of breath disease marker substances and diseases is made into a radar chart for each disease is stored in advance. It is. This database is a database in which the minimum concentrations (threshold concentrations) of a plurality of breath disease marker substances that can be generally determined to be the disease are radar charts for each disease and for each disease.

The disease diagnosis apparatus according to the present embodiment is similar to the chemical substance detection apparatus 3 according to the second embodiment. The sensor element 101a detects NO, the sensor element 101b detects H ₂ O ₂ , the sensor element 101c detects CO, and pentane. Sensor elements 101d for detecting the same are arranged in the same arrangement. All of these four chemical substances are breath disease marker substances associated with lung diseases.

(Disease diagnosis experiment)
A breath analysis experiment was conducted in the same manner as in Example 2 using the same human breath as in Example 2, and the characteristic values of the sensor elements were measured. The results are shown in Table 19. The actually measured characteristic values are the same as those described in Table 17 above.

Based on the actually measured characteristic values, the NO, CO, H ₂ O _2, and pentane concentrations in appropriately corrected human breath were calculated in the same manner as in Example 2. The results are shown in Table 20. This result is the same as that described in Table 18 above. In Table 20, the exhaled disease marker substance concentration obtained using the disease diagnosis apparatus of Reference Example 5 described later and the exhaled disease marker substance concentration obtained in Reference Example 4 are also shown. Yes.

The NO, CO, H ₂ O ₂ and pentane concentrations in human breath obtained by the above breath analysis are converted into radar charts, which are compared with the disease-specific radar charts in the database unit 204, thereby having the closest pattern. Selected disease. Next, each breath disease marker substance concentration obtained by breath analysis was compared with the threshold concentration of the breath disease marker substance in the selected disease, and the disease risk was evaluated at five levels.

<Reference Example 5>
Except for adopting only two kinds of NO and pentane as expiratory disease marker substances, and selecting diseases and evaluating the risk of diseases based on these two expiratory disease marker substance concentrations. The disease diagnosis experiment was conducted in the same manner as in 3.

[Results and Evaluation of Disease Diagnosis Experiment of Example 3 and Reference Example 5]
Table 21 shows threshold concentrations of exhaled disease marker substances in asthma, COPD (chronic obstructive pneumonia), CF (cystic fibrosis) and lung cancer, and concentrations of these exhaled disease marker substances in normal Indicates. Table 21 also shows measured concentrations in human breath of each of the breath disease marker substances obtained in Example 3 and Reference Example 5. Note that “Ave.” in Table 21 indicates that the patient is not suffering from a disease, that is, is at a level equivalent to that in a normal state.

Table 22 shows that the breath disease marker substance concentration in normal is 1, the threshold concentration of each breath disease marker substance, and each breath disease marker substance obtained in Example 3 and Reference Example 5 in human breath It is a numerical value when the measured concentration is converted as a ratio to the concentration of a disease marker substance in breath during normal operation. FIG. 16 shows the ratio of the threshold concentration of each breath disease marker substance shown in Table 22 to the breath disease marker substance concentration in normal conditions (FIGS. 16 (a) to (d)). And the ratio (FIGS. 16 (e) and (f)) of the measured concentration in human breath of each breath disease marker substance obtained in Reference Example 5 to the breath disease marker substance concentration in normal state (FIGS. 16 (e) and (f)) was made into a radar chart. Is.

Comparing the radar charts of the measured breath disease marker substance concentrations obtained in Example 3 shown in FIG. 16 (e) with the radar charts of the respective lung diseases (FIGS. 16 (a) to (d)), Since the radar chart pattern of FIG. 16 (e) is closest to the pattern of FIG. 16 (b), it is sufficiently inferred that the subject's disease is COPD among lung diseases. On the other hand, depending on the radar chart pattern of Reference Example 5 shown in FIG. 16 (f), it is difficult to determine whether it is COPD or other pulmonary disease because there are few types of breath disease marker substances to be measured. is there.

Next, when the actually-exhaled breath disease marker substance concentration obtained in Example 3 was compared with the threshold concentration of the breath disease marker substance in COPD, the actually measured value in CO exceeded the threshold concentration. Since the measured value is very close to the threshold concentration, “Level 3 (disease risk)” was diagnosed. On the other hand, in the case of Reference Example 5, since it is difficult to determine the type of lung disease, it is difficult to evaluate disease risk. Thus, in order to accurately distinguish different diseases belonging to the same type of disease and to evaluate the risk of the disease, it is preferable to increase the types of breath disease marker substances to be measured.

The present invention is not limited to the above embodiment. Of course, it can be implemented with appropriate modifications. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

According to the present invention, it is possible to provide a chemical substance detection apparatus that is small, simple, and capable of measuring a plurality of target chemical substances in a sample gas with high accuracy. Furthermore, such a chemical substance detection apparatus can be suitably applied to a disease diagnosis apparatus for quantifying a plurality of expired breath disease marker substances in human breath and diagnosing a disease with high accuracy. As a result, it has become possible to provide a disease diagnosis apparatus that is small, simple, non-invasive, and highly accurate, and has made steady progress toward the realization of a preventive medical society.

1, 2, 3 chemical substance detection device, 10, 10a, 10b sensor array, 11 chamber, 12 gas introduction route, 12a gas introduction port, 13 gas discharge route, 13a gas discharge port, 14 reference sensor, 15 conductor, 16a resistance Tube, 16b permselective membrane, 16c mass flow controller, 16d constant flow pump, 20 computer, 21 digital multimeter, 22 USB interface, 30 tedlar bag, 31 mouthpiece, 32 gas tight syringe, 60 dedicated holder, 61 manganese dioxide fixed membrane , 62 metal part, 63 Peltier element, 64 oxygen selective permeable membrane, 65 Pt electrode, 66 Ag electrode, 67 electrolyte, 68 ammeter, 70 dissolved oxygen sensor, 71 analyte gas condensate, 100 substrate, 101, 101 , 101b, 101c, 101d sensor element, 102 sensor temperature control unit, 103 heat insulation unit, 104 positive electrode, 105 negative electrode, 106 sensing unit, 107 insulator, 108 constant resistance, 109 metal complex, 201 interface, 202 CPU, 203 data storage Part, 204 database part, 301 A valve, 302 B valve.

Claims (26)

A chemical substance detection device for measuring the concentration of a chemical substance contained in a sample gas,
A chamber having a gas inlet and a gas outlet;
A gas introduction path connected to the gas introduction port for introducing the sample gas into the chamber;
A gas discharge path connected to the gas discharge port for discharging the sample gas from the chamber;
One or more sensor arrays arranged in the chamber, the sensor elements for detecting the chemical substance being arranged on a substrate;
A signal receiving unit for receiving a signal from the sensor element;
A chemical substance detection apparatus comprising: A chemical substance detection apparatus for measuring the concentration of a plurality of chemical substances contained in a sample gas,
2. The chemical substance detection apparatus according to claim 1, wherein one or two or more sensor arrays arranged in the chamber include two or more sensor elements in total. The chemical substance detection apparatus according to claim 1, further comprising a reference sensor for detecting a physical state of the specimen gas. 4. The chemical substance detection apparatus according to claim 3, wherein the reference sensor is installed inside the gas introduction path. The reference sensor is a temperature sensor for detecting the temperature of the specimen gas, a humidity sensor for detecting relative humidity, or a temperature / humidity sensor for detecting temperature and / or relative humidity. 4. The chemical substance detection apparatus according to item 3. 4. The chemical substance detection apparatus according to claim 3, wherein the reference sensor is a sensor for detecting a flow rate of the specimen gas. The chemistry according to claim 3, wherein the concentration of the chemical substance calculated based on a signal from the sensor element is corrected based on information on a physical state of the specimen gas obtained by the reference sensor. Substance detection device. The chamber has the gas inlet and the gas outlet on its side surface,
The chemical substance detection apparatus according to claim 2, wherein at least one of the sensor arrays is disposed at a position lower or higher than the gas inlet and the gas outlet. Comprising two sensor arrays disposed in the chamber;
One sensor array is disposed at a position lower than the gas inlet and the gas outlet,
9. The chemical substance detection apparatus according to claim 8, wherein the other sensor array is disposed at a position higher than the gas inlet and the gas outlet. The specimen gas includes the chemical substance having a specific gravity smaller than the atmospheric gas in the chamber,
9. The range according to claim 8, wherein any one or more of the two or more sensor elements is disposed on a substrate of a sensor array disposed at a position higher than the gas inlet and the gas outlet. The chemical substance detection apparatus described in 1. The specimen gas includes the chemical substance having a specific gravity greater than the atmospheric gas in the chamber,
9. The range according to claim 8, wherein any one or more of the two or more sensor elements is disposed on a substrate of a sensor array disposed at a position lower than the gas inlet and the gas outlet. The chemical substance detection apparatus described in 1. The specimen gas includes two or more kinds of gaseous chemical substances having different specific gravities,
At least one sensor array comprises two or more sensor elements;
9. The chemical substance detection according to claim 8, wherein the two or more sensor elements are arranged such that a sensor element for detecting a chemical substance having a higher specific gravity is closer to the gas inlet. apparatus. The chemical substance detection device according to claim 1, wherein the sensor element includes a semiconductor sensor or a nanostructure sensor. 14. The chemical substance detection apparatus according to claim 13, wherein the part for detecting the chemical substance of the nanostructure sensor is composed of carbon nanotubes. 14. The chemical substance detection apparatus according to claim 13, wherein the nanostructure sensor is composed of carbon nanotubes whose surface for detecting the chemical substance is surface-modified with a metal complex. The chemical substance detection device according to claim 1, wherein the at least one sensor array includes a sensor temperature control unit for controlling the temperature of any one or more sensor elements arranged on the substrate. The chemical substance detection device according to claim 16, wherein the sensor temperature control unit includes a heating element or a cooling element. At least one sensor array has two or more sensor elements and the cooling element;
18. The chemical substance detection apparatus according to claim 17, wherein the sensor element whose temperature is controlled by the cooling element is disposed closer to the gas discharge port than other sensor elements included in the sensor array. At least one sensor array has two or more sensor elements;
The chemical substance detection device according to claim 16, further comprising a heat insulating portion for thermally separating adjacent sensor elements. The heat insulation part includes a heat insulating material interposed in a substrate located between the adjacent sensor elements or a groove formed in a substrate located between the adjacent sensor elements. Chemical substance detection equipment. The chemical substance detection apparatus according to claim 1, further comprising a gas flow rate control unit for controlling the flow rate of the specimen gas flowing through the chamber. The chemical substance detection device according to claim 21, wherein the gas flow rate control unit is a resistance tube, a permselective membrane, a mass flow controller, or a constant flow rate pump. The concentration of the chemical substance calculated based on the signal from any one of the sensor elements is corrected based on information on the influence of substances other than the chemical substance to be detected by the sensor element on the signal of the sensor element. The chemical substance detection apparatus according to claim 1 to be performed. A chemical substance detection device for measuring the concentration of a chemical substance contained in human breath,
The chemical substance detection apparatus according to claim 1, further comprising a disease database indicating a relationship between the concentration of the chemical substance and a disease. 25. The chemical substance detection apparatus according to claim 24, wherein the chemical substance detection apparatus is configured so that a disease of a subject can be diagnosed from the obtained concentration value of the chemical substance with reference to the disease database. A chemical substance detection apparatus for measuring the concentration of a plurality of chemical substances contained in human breath,
25. The chemical substance detection apparatus according to claim 24, wherein the plurality of chemical substances include NO, CO, and H ₂ O ₂ .

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