Chemical Sensor System

Abstract

To provide a chemical sensor system capable of detecting a target substance at high accuracy and with high responsiveness.SOLUTION: A chemical sensor system is equipped with: a first chemical sensor; a second chemical sensor unit; and a first analyte atmosphere tank positioned between the first chemical sensor and the second chemical sensor unit. The chemical sensor system includes an air supply mechanism which executes: a first operation for supplying an analyte atmosphere from the first chemical sensor to a first analyte atmosphere tank; a second operation for supplying an analyte atmosphere from the first analyte atmosphere tank to the second chemical sensor unit; and a third operation for exhausting the analyte atmosphere in the first analyte atmosphere tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to chemical sensor systems. [Background technology]

[0002] Chemical sensors that detect target substances in the gas phase can be used to detect gases and odors by detecting components released into the air from samples. Gas and odor detection requires both high accuracy and responsiveness. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-046263 [Patent Document 2] Patent Publication No. 2021-047051 Summary of the Invention [Problem to be solved by the invention]

[0004] However, sensors that detect target substances in the gas phase respond quickly but may have difficulty achieving high selectivity, whereas sensors that detect target substances in the liquid phase generally achieve high selectivity but require a long detection time.

[0005] This problem can be solved by directly connecting the gas-phase sensor and the liquid-phase sensor and sensing the same analyte simultaneously. If screening is performed using the gas-phase sensor and the liquid-phase sensor continues sensing only for analytes for which there is a response, the time spent continuing sensing for analytes for which there is no response in the gas-phase sensor screening can be eliminated. However, if there is a response in the gas-phase sensor screening, it is not possible to move on to sensing the next analyte until the liquid-phase sensor has completed sensing.

[0006] Therefore, the problem to be solved by the present invention is to provide a chemical sensor system that can detect a target substance with high accuracy and responsiveness. [Means for solving the problem]

[0007] According to an embodiment, there is provided a gas supply mechanism including a first chemical sensor, a second chemical sensor unit, and a first specimen atmosphere tank located between the first chemical sensor and the second chemical sensor unit, the gas supply mechanism performing a first operation of supplying the specimen atmosphere from the first chemical sensor to the first specimen atmosphere tank, a second operation of supplying the specimen atmosphere from the first specimen atmosphere tank to the second chemical sensor unit, and a third operation of exhausting the specimen atmosphere from the first specimen atmosphere tank. a second chemical sensor unit including a mechanism for exposing a sample atmosphere to a sensing solution, a second chemical sensor that responds to a target substance contained in the sensing solution to which the sample atmosphere is exposed, and a valve located between the first sample atmosphere tank and the second chemical sensor unit, wherein the first chemical sensor is a gas-phase sensor and the second chemical sensor is a liquid-phase sensor; A chemical sensor system is provided. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of a chemical sensor system according to an embodiment. [Figure 2] FIG. 2 is a configuration diagram showing an example of a first chemical sensor in the chemical sensor system according to the embodiment. [Figure 3] FIG. 3 is a schematic diagram showing an example of a second chemical sensor unit in the chemical sensor system according to the embodiment. [Figure 4] FIG. 2 is a schematic diagram showing an example of a sample atmosphere intake unit in the chemical sensor system according to the embodiment. [Figure 5] FIG. 3 is a perspective view showing an example of a second chemical sensor in the chemical sensor system according to the embodiment. [Figure 6] FIG. 3 is a schematic diagram of a second chemical sensor mounting portion in the chemical sensor system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components that perform the same or similar functions are designated by the same reference numerals throughout the drawings, and duplicate descriptions will be omitted. Each drawing is a schematic diagram for explaining and facilitating understanding of the embodiments, and the shapes, dimensions, ratios, etc. may differ from those of an actual device. However, these may be appropriately modified in design, taking into consideration the following description and known techniques.

[0010] [First embodiment] According to a first embodiment, there is provided a chemical sensor system comprising a first chemical sensor, a second chemical sensor unit, and a first specimen atmosphere tank located between the first chemical sensor and the second chemical sensor unit, and having an air supply mechanism that performs a first operation of supplying specimen atmosphere from the first chemical sensor to the first specimen atmosphere tank, a second operation of supplying specimen atmosphere from the first specimen atmosphere tank to the second chemical sensor unit, and a third operation of exhausting the specimen atmosphere in the first specimen atmosphere tank.

[0011] 1 is a schematic diagram of a chemical sensor system according to the first embodiment, which will be described with reference to FIG.

[0012] The chemical sensor system 1000 includes a first chemical sensor 2, a first sample atmosphere tank 3, a second chemical sensor unit 4, a first valve 5, a second valve 6, a third valve 7, a first control circuit 9, a first determination circuit 13, and a second determination circuit 14. The chemical sensor system 1000 is a system for detecting target substances (odor components) contained in a sample atmosphere. In this specification, odor components refer to substances that can be detected in the gas phase or liquid phase by a chemical sensor, and do not necessarily react with olfactory receptors in living organisms. The chemical sensor system 1000 is the area surrounded by a dashed line in FIG. 1.

[0013] The intake port 1 is the portion through which the sample atmosphere is taken in. The airtight path 10 is connected to the intake port 1. Here, the airtight path refers to a structure that allows gas to circulate inside the path while maintaining airtightness from the outside. A resin or metal pipe can be used as the airtight path. The intake port 1 is attached to the end of the airtight path 10 that takes in the sample atmosphere from the object, and depending on the shape of the object, it may have a narrow, narrow shape, a wide, open shape, or, if necessary, a gasket that adheres to the object. The intake port 1 can be equipped with a pump or fan as an air supply mechanism for transporting the sample atmosphere.

[0014] The first chemical sensor 2 is a device that detects a target substance or a group of target substances containing the target substance contained in the introduced sample atmosphere and outputs the detected substance as an electrical signal expressed as a voltage value, a current value, or the like to the first judgment circuit 13. The first chemical sensor 2 is a gas-phase sensor. The first chemical sensor 2 is connected to the airtight path 10. A change in the electrical signal of the chemical sensor when a specific substance is present is referred to as a response. The substances to which the first chemical sensor 2 responds are referred to as a group of target substances.

[0015] The airtight path 11 is an exhaust path. One end of the airtight path 11 is connected to the first specimen atmosphere tank 3. The other end of the airtight path 11 is connected to the second valve 6. When the second valve 6 is opened, the airtight path 11 is released and connected to, for example, the outside of the path.

[0016] The first specimen atmosphere tank 3 collects the specimen atmosphere supplied via the airtight path 10 and the first chemical sensor 2. The first specimen atmosphere tank 3 may include a volume control device 103 and a first valve 5, a second valve 6, and a third valve 7 as an air supply mechanism. The first valve 5, the second valve 6, and the third valve 7 open and close in response to signals input from the first control circuit 9. The volume control device 103 variably controls the internal volume of the tank when a signal is input from the first control circuit 9. The volume control device 103 is, for example, a pump with an actuator. The air supply mechanism can be realized in any configuration as long as it can supply the specimen atmosphere from the first chemical sensor 2 to the first specimen atmosphere tank 3 and supply the specimen atmosphere from the first specimen atmosphere tank 3 to the second chemical sensor unit 4. The air supply mechanism can also be realized by a pump, fan, and valve provided separately from the first specimen atmosphere tank 3.

[0017] The airtight path 12 connects the first specimen atmosphere tank 3 and the second chemical sensor unit 4. The airtight path 12 is provided with a third valve 7 so as to separate the first specimen atmosphere tank 3 and the second chemical sensor unit 4 from each other.

[0018] The second chemical sensor unit 4 includes a second chemical sensor. The second chemical sensor detects a target substance or a group of target substances containing the target substance contained in the introduced sample atmosphere and outputs the detected substance as an electrical signal represented by a voltage value, a current value, or the like to the second judgment circuit 14. The second chemical sensor is a liquid-phase sensor. The second chemical sensor unit 4 performs detection by contacting the substance contained in the introduced sample atmosphere with a solvent to form a sample solution, and then contacting the second chemical sensor with the sample solution. The substance to which the second chemical sensor responds is referred to as a target substance. The target substance is included in the group of target substances. The second chemical sensor has higher selectivity than the first chemical sensor 2. The second response time, which is the time required for a response to be obtained after the sample atmosphere is introduced into the second chemical sensor unit 4, is longer than the first response time, which is the time required for a response to be obtained after the sample atmosphere is introduced into the first chemical sensor 2.

[0019] The first determination circuit 13 is a circuit that determines whether the first chemical sensor 2 has responded. The first determination circuit 13 is connected to the signal output of the first chemical sensor 2. The first determination circuit 13 analyzes the output signal of the first chemical sensor 2 and determines whether the sample atmosphere contains a specified amount of target substances, including the target substance. The first determination circuit 13 can store the time when the first chemical sensor 2 tested the sample contained in the collected sample atmosphere and the test results. The test time can be stored as time or as time information based on the start-up of the chemical sensor system 1000.

[0020] The first determination circuit 13 may identify the characteristics and type of substance contained in the sample atmosphere based on the response of the first chemical sensor 2. The determination method of the first determination circuit 13 is not particularly limited and can be selected appropriately depending on the type and characteristics of the first chemical sensor 2. For example, the first determination circuit 13 may determine whether the signal strength of the first chemical sensor 2 is equal to or greater than a specified value, or may compare the signal strength with reference parameters stored within the first determination circuit 13 to determine the similarity and identify the type of substance. The first determination circuit 13 may be connected to an I / F and output the determination result to the I / F.

[0021] The second determination circuit 14 determines whether the second chemical sensor has responded. The second determination circuit 14 is connected to the output of the second chemical sensor (described later). The second determination circuit 14 analyzes the output signal of the second chemical sensor and determines whether the sample atmosphere tested by the second chemical sensor after responding to the first chemical sensor 2 contains a predetermined amount of target substance. The second determination circuit 14 can store the time when the second chemical sensor tested the sample atmosphere and the test results. It can also record the time when the sample atmosphere was collected at an intake port such as the intake port 1 and the test results of the first chemical sensor 2 and the second chemical sensor in association with each other. This allows the sample atmosphere and the sample atmosphere tested by the first chemical sensor 2 and the second chemical sensor to be synchronized, enabling accurate management of the test results of the sample atmosphere. The second determination circuit 14 may be connected to an interface (not shown) and can output the test results to the interface.

[0022] The first judgment circuit 13 and the second judgment circuit 14 can be realized as dedicated circuits, or as a single CPU (Central Processing Unit) that functions as each circuit. The first judgment circuit 13 and the second judgment circuit 14 have one or more storage media that store test results, reference parameters, and programs. The storage media of the first judgment circuit 13, the second judgment circuit 14, and the first control circuit 9 can also be realized as the same configuration that shares functions.

[0023] The first control circuit 9 controls the first to third valves 5 to 7 and the volume control device 103 in the chemical sensor system 1000 according to this embodiment. The first control circuit 9 also controls the valve connected to the second sample atmosphere tank 20 and the volume control device associated with the tank. The first control circuit 9 is connected to the aforementioned components and the first determination circuit 13, receives a signal from the first determination circuit 13 based on the test results of the first chemical sensor 2, and outputs a control signal to the aforementioned components. The first control circuit 9 can also receive a signal to start sample atmosphere collection, which also outputs a control signal to the aforementioned components. The signal to start sample atmosphere collection can be input by an operator using the chemical sensor system, or it can be automatically transmitted by robot operation, image recognition, or the like, upon determining that the intake port 1 is in a sample atmosphere collection state. While FIG. 1 shows an example in which the first control circuit 9, the aforementioned components, and the first determination circuit 13 are connected wirelessly (not shown), they may also be connected via wires. Furthermore, the transmission path for the signal to start collecting the sample atmosphere is shown as an example of a wireless connection, but may also be connected by wire. The first control circuit 9 controls the opening and closing timing of the first to third valves 5 to 7 and the drive of the volume control device 103 based on the output of the control signal and the sample atmosphere collection start signal, thereby controlling whether the sample atmosphere is collected in the sample atmosphere tank 3, whether the sample atmosphere collected in the sample atmosphere tank 3 is evacuated, or whether it is sent to the second chemical sensor unit 4. Furthermore, the first control circuit 9 also controls the second sample atmosphere tank 20, the valves connected thereto, and the associated volume control devices, to control whether the sample atmosphere is collected in the second sample atmosphere tank 20, whether the sample atmosphere collected in the sample atmosphere tank 20 is evacuated, or whether it is sent to the third chemical sensor unit 21.

[0024] The first control circuit 9 can control each of the above-mentioned components by causing a processor such as a CPU to execute a program. The control circuit includes, for example, an arithmetic unit such as a CPU, a storage device connected to the arithmetic unit and storing programs and data, and a signal generation device that generates signals to be output to the components controlled by the control circuit.

[0025] FIG. 2 is a configuration diagram showing an example of a first chemical sensor in the chemical sensor system according to the embodiment.

[0026] As an example of a first chemical sensor, we will explain the ceramic semiconductor gas-phase sensor device shown in Figure 2. The gas-phase sensor device is made of a porous sintered n-type semiconductor material, such as tin oxide or zinc oxide. Oxygen from the air adsorbs to the surface of the n-type semiconductor in a negatively charged state, forming a depletion layer near the surface of the n-type semiconductor, resulting in a high resistance state, as shown in Figure (a). When the gas-phase sensor device is exposed to a reducing atmosphere, such as carbon monoxide, at high temperatures, the carbon monoxide reacts with the oxygen on the n-type semiconductor surface, reducing the amount of oxygen adsorbed to the surface. As a result, the depletion layer on the n-type semiconductor surface becomes thinner, resulting in a low resistance state, as shown in Figure (b). This change depends on the carbon monoxide concentration, and similar phenomena occur with other combustible gases. Using this principle, the concentrations of various combustible gases can be detected (Figure (c)).

[0027] Gas-phase sensors respond quickly, but also respond to substances (target substance group) that have the same properties as the target substance (physical properties such as reduction and flammability). As is clear from Figure 2(c), if the type of gas contained in the gas phase is unknown, it cannot be converted to concentration, and if the concentration is unknown, the type of gas cannot be determined. In other words, it is difficult to apply them to applications that test unknown sample atmospheres. Note that the type and detection method of the first chemical sensor are not limited to ceramic semiconductor-type sensor devices, as long as the gas phase comes into contact with the sensor element. Any testing device and testing method can be used, such as solid electrolyte-type sensors or sensors using graphene FETs.

[0028] FIG. 3 is a schematic diagram showing an example of a second chemical sensor unit in the chemical sensor system according to the embodiment.

[0029] An example of the second chemical sensor unit will be described with reference to FIG.

[0030] The second chemical sensor unit 4 includes a mechanism for exposing the sample atmosphere to a sensing solution, and a second chemical sensor for detecting substances contained in the sensing solution to which the sample atmosphere has been exposed.

[0031] The specimen atmosphere intake unit 400 is connected to the airtight path 12 and a pipe 452 (shown in FIG. 4). A suction / exhaust device 443 (shown in FIG. 4) is connected to the pipe 452 as needed. The suction / exhaust device 443 is, for example, a pump or a fan. When the first and second valves shown in FIG. 1 are closed and the third valve is opened, and the internal volume of the first specimen atmosphere tank 3 is reduced using the volume control device 103, the specimen atmosphere is sent into the gas-liquid contact container 411 in the specimen atmosphere intake unit 400 via the airtight path 12. At this time, a balance with the exhaust from the gas-liquid contact container 411 may be achieved using the suction / exhaust device 443 installed as needed.

[0032] The gas-liquid contactor 411 is connected to a supply source of an organic solvent. For example, the gas-liquid contactor 411 (shown in FIG. 4) is connected to an organic solvent tank 441 (shown in FIG. 4) in which an organic solvent is stored, via a pipe 454 (shown in FIG. 4), a pipe 455 (shown in FIG. 4), and a valve 471 (shown in FIG. 4). The organic solvent is a hydrophilic organic solvent, and is, for example, any one selected from the group consisting of lower alcohols such as ethanol and methanol, DMSO (Dimethyl Sulfoxide), DMF (N,N-dimethylformamide), acetone, and acetonitrile.

[0033] An organic solvent is supplied from an organic solvent tank 441 to the gas-liquid contact vessel 411. The gas-liquid contact vessel 411 exposes the sample atmosphere, which may contain hydrophobic target molecules, to the hydrophilic organic solvent.

[0034] The gas-liquid contact container 411 in the sample atmosphere taking-in unit 400 is connected to a pipe 453 for draining liquid, and a valve 473 is connected to the pipe 453. The gas-liquid contact container 411 in the sample atmosphere taking-in unit 400 is also connected to the measurement unit 444 via a pipe 456 (shown in FIG. 4), a valve 472 (shown in FIG. 4), and a pipe 457.

[0035] The organic solvent tank 441 is connected to the metering unit 444 via a pipe 454 , a valve 471 , a pipe 456 , a valve 472 (shown in FIG. 4), and a pipe 457 .

[0036] The metering unit 444 is connected to a pipe 459 for draining the liquid, and a valve 474 is connected to the pipe 459. The metering unit 444 is also connected to the mixing unit 420 via a pipe 461, and a valve 475 is connected to the pipe 461.

[0037] Further, a supply source of an aqueous solution is connected to the mixing unit 420. For example, the mixing unit 420 is connected to an aqueous solution tank 442 that stores an aqueous solution via a measuring unit 445. A valve 476 is connected to a pipe 462 that connects the aqueous solution tank 442 and the measuring unit 445. A valve 478 is connected to a pipe 463 that connects the mixing unit 420 and the measuring unit 445. The aqueous solution is, for example, a phosphate buffer solution, a HEPES buffer solution, a Tris-HCl buffer solution, or the like.

[0038] The mixing unit 420 is supplied with an organic solvent containing target molecules from the sample atmosphere intake unit 400, and further supplied with an aqueous solution from the aqueous solution tank 442. Then, the mixing unit 420 mixes the organic solvent containing the target molecules with the aqueous solution to prepare a sample liquid.

[0039] Mixing unit 420 is connected to second chemical sensor 530 via piping 464. A valve 477 is connected to piping 464. Furthermore, mixing unit 420 is connected to piping 466 for draining liquid as needed, and a valve 479 is connected to piping 466.

[0040] The second chemical sensor 530 is connected to a pipe 465 for draining the liquid, and a valve 481 is connected to the pipe 465 .

[0041] Next, the specimen atmosphere intake unit will be described with reference to Fig. 4. Fig. 4 is a schematic diagram showing an example of the specimen atmosphere intake unit.

[0042] The specimen atmosphere intake unit has a gas-liquid contact container 411 that bubbles the specimen atmosphere into the organic solvent. The container 411 is connected to an organic solvent tank 441 via a pipe 454, a valve 471, and a pipe 455. A pump 412 is connected to the pipe 454. By opening the valve 471 and driving the pump 412, the organic solvent stored in the organic solvent tank 441 is supplied into the container 411.

[0043] One end of the airtight path 12 is connected to a specimen atmosphere tank (not shown in Figure 4). The other end of the airtight path 12 is located in the organic solvent 401 in the container 411. Furthermore, one end of the pipe 452 is located in the gas phase above the organic solvent 401 in the container 411, and the other end of the pipe 452 serves as an exhaust port. If necessary, an intake / exhaust device 443 is connected between the container 411 and the exhaust port. When the first and second valves shown in Figure 1 are closed and the third valve is open, and the internal volume of the first specimen atmosphere tank 3 is reduced using the volume control device 103, the specimen atmosphere sent from the airtight path 12 is bubbled into the organic solvent 401 in the container 411, and the target molecules in the specimen atmosphere are dissolved in the organic solvent 401.

[0044] The container 411 is connected to a metering unit 444 via a pipe 456, a valve 472, and a pipe 457. By opening the valve 472 and driving the pump 413, the organic solvent containing the target molecules in the container 411 is supplied to the metering unit 444. After a desired amount of organic solvent has been supplied to the metering unit 444, the organic solvent remaining in the container 411 is discharged from the pipe 453 by opening the valve 473. Furthermore, in order to clean the inside of the container 411, it is also possible to purge the container 411 with the organic solvent 401 without bubbling the sample atmosphere, and in this case, the organic solvent 401 used for cleaning can also be discharged via the same route. FIG. 5 is a perspective view showing an example of a second chemical sensor in the chemical sensor system according to the embodiment.

[0045] Next, an example of the second chemical sensor will be described with reference to Fig. 5. The second chemical sensor is a liquid phase sensor.

[0046] Second chemical sensor 530 is, for example, a charge detection element including graphene film 531. The surface of second chemical sensor 530 (for example, the surface of graphene film 531) is exposed to specimen liquid 500 obtained by mixing an organic solvent containing target molecules with an aqueous solution in mixing unit 420.

[0047] The second chemical sensor 530 has, for example, a field effect transistor (FET) structure.

[0048] The second chemical sensor 530 has a substrate 533 and a base film 534 provided over the substrate 533. A graphene film 531 is provided over the base film 534. Alternatively, the graphene film 531 may be provided on the surface of the substrate 533 without providing the base film 534. Furthermore, the substrate 533 may have a circuit or a transistor (not shown) formed thereon.

[0049] The substrate 533 may be made of, for example, silicon, silicon oxide, glass, or a polymer material. The base film 534 may be an insulating film such as a silicon oxide film. The base film 534 may also function as a chemical catalyst for forming the graphene film 531.

[0050] The second chemical sensor 530 also has at least two electrodes: a first electrode 535 and a second electrode 536. One of the first electrode 535 and the second electrode 536 functions as a drain electrode, and the other functions as a source electrode.

[0051] The first electrode 535 and the second electrode 536 are covered with a protective insulating film 537 as needed. The protective insulating film 537 is made of, for example, aluminum oxide, silicon oxide, or a polymer.

[0052] If necessary, a gate wiring G is further formed on the base film 534 of the second chemical sensor 530, and a part of the gate wiring G is exposed without being covered with the protective insulating film 537. The part of the gate wiring G exposed from the protective insulating film 537 is made of a gold, platinum, silver, or silver-silver chloride laminated film, etc.

[0053] Note that the gate line G does not necessarily have to be formed on the second chemical sensor 530, as long as it is in contact with the sample liquid 500 near the second chemical sensor 530. For example, the gate line G may be formed on an element separate from the second chemical sensor 530, and connected to the second chemical sensor 530 via the sample liquid 500.

[0054] A graphene film 531 is provided between a first electrode 535 and a second electrode 536. The first electrode 535 and the second electrode 536 are in electrical contact with the graphene film 531. A current can flow between the first electrode 535 and the second electrode 536 through the graphene film 531.

[0055] The second chemical sensor 530 further includes a probe molecule 532 that selectively associates with the target molecule on its surface. The probe molecule 532 is bound to or adsorbed on the surface of the graphene film 531. The probe molecule has the property of specifically binding to or adsorbing to the target substance and can be optionally modified to suit the target substance. The probe molecule may be, but is not limited to, a nucleic acid, an enzyme, a peptide, or a synthetic molecule or derivative thereof.

[0056] The sensor element surface including the graphene film 531 is exposed to the inside of a flow channel to which a sample liquid 500 is supplied. The surface of the graphene film 531, the probe molecules 532, and the gate wiring G are exposed to the sample liquid 500.

[0057] FIG. 6 is a schematic diagram of a second chemical sensor mounting portion in the chemical sensor system according to the embodiment.

[0058] As shown in Fig. 6(a), a window 600 is formed in the second chemical sensor mounting portion of pipes 464 and 465, and a packing 610 is formed around the outer periphery of window 600. Second chemical sensor 530 is mounted on cartridge substrate 601, and as shown in Fig. 6(b), when the sensor element surface is installed facing window 600, the packing 610 provides an airtight seal, and the sensor element surface is exposed inside pipes 464 and 465. This configuration allows second chemical sensor 530 to be attached and detached as a replacement part or a consumable part.

[0059] The second chemical sensor 530 electrically detects that the probe molecule 532 has associated with the target molecule. When the probe molecule 532 recognizes and captures the target molecule, the target molecule approaches the surface of the graphene film 531, and the electronic state of the graphene film 531 changes depending on, for example, the charge, polarization, electron-withdrawing / donating properties, etc., of the target molecule. By electrically detecting this, the presence and concentration of the target molecule can be determined.

[0060] When electrically detecting the electronic state of the graphene film 531, the electrical properties of the graphene can be adjusted to a state where they are highly sensitive by applying a desired gate potential to the sample solution via the gate electrode.

[0061] Alternatively, by measuring the source-drain current of the graphene while scanning the gate potential, it is possible to measure the charge neutrality point where the carriers flowing within the graphene switch between holes and electrons, and thereby determine the state of charge injection into the graphene.

[0062] If necessary, the surface of the graphene film 531 may be covered with an insulator, such as a peptide β-sheet or a phospholipid membrane.

[0063] The following describes the operation of the chemical sensor unit 1000. The operation described below is realized by the first control circuit 9 controlling the operations of the first to third valves 5 to 7 and the volume control device 103. The above operations 1 to 7 may be performed simultaneously by different components.

[0064] Operation 1. The gas supply mechanism supplies the sample atmosphere from the first chemical sensor 2 to the first sample atmosphere tank. For example, if the volume control device 103 increases the internal volume of the first sample atmosphere tank 3 while the first valve 5 is open and the second and third valves 6 and 7 are closed, the pressure inside the first sample atmosphere tank 3 is reduced. The sample atmosphere flows into the first sample atmosphere tank 3 via the airtight path 10.

[0065] Operation 2: The first chemical sensor 2 senses the incoming sample atmosphere.

[0066] Operation 3. The first determination circuit 13 determines whether the first chemical sensor 2 has responded. If the first chemical sensor 2 has not responded, it is determined that the sample atmosphere does not contain a target substance or a sample substance group, and the process proceeds to operation 4. If the first chemical sensor 2 has responded and the second chemical sensor unit 4 is not performing a sensing operation, it is determined that the sample atmosphere contains a sample substance group, and the process proceeds to operation 5. If the first chemical sensor 2 has responded and the second chemical sensor unit 4 is performing a sensing operation, the process proceeds to operation 5 after the second chemical sensor unit 4 finishes its sensing operation (after operation 7 for the previous sample atmosphere is completed).

[0067] Operation 4. The gas supply mechanism discards the sample atmosphere collected in the first sample atmosphere tank 3. For example, the first valve 5 and the third valve 7 are closed, the second valve 6 is opened, and the volume control device 103 reduces the internal volume of the first sample atmosphere tank 3, thereby exhausting the sample atmosphere collected in the first sample atmosphere tank 3. After exhaustion is complete, the process returns to Operation 1, or operation is stopped and the chemical sensor system 1000 enters a standby state.

[0068] Operation 5. The gas supply mechanism supplies the sample atmosphere from the first sample atmosphere tank to the second chemical sensor unit 4. For example, the first valve 5 and the second valve 6 are closed, the third valve 7 is opened, and the volume control device 103 reduces the internal volume of the first sample atmosphere tank, so that the sample atmosphere collected in the first sample atmosphere tank 3 is sent to the second chemical sensor unit 4.

[0069] Operation 6: The second chemical sensor unit 4 senses the incoming sample atmosphere.

[0070] Operation 7. The second determination circuit 14 determines whether or not the second chemical sensor has responded. Depending on the determination result, it is determined whether or not the target substance is contained in the sample atmosphere.

[0071] As shown in the above operations 1 to 7, the second chemical sensor, which has high selectivity but a long response time, performs sensing when the first chemical sensor 2, which has a short response time, responds. The first chemical sensor 2 can continuously sense a large amount of sample atmosphere by repeating operations 1 to 4, as long as the first chemical sensor 2 does not respond while the second chemical sensor unit 4 is sensing. The first chemical sensor unit 2 and the second chemical sensor unit 4 can perform sensing operations simultaneously. The chemical sensor system 1000 can improve the amount of sample that can be processed per unit time (sensing speed) while maintaining high selectivity.

[0072] The following describes optional components that may be provided in the chemical sensor system according to the present embodiment. The chemical sensor system according to the present embodiment may further include a third chemical sensor unit 21 and a second sample atmosphere tank 20 located between the first chemical sensor 2 and the third chemical sensor unit 21. The third chemical sensor unit 21 has a configuration similar to that of the second chemical sensor. The second sample atmosphere tank has a configuration similar to that of the first sample atmosphere tank 3. The chemical sensor system 1000 further includes an air supply mechanism that performs a fourth operation of supplying the sample atmosphere to be tested by the first chemical sensor 2 to the second sample atmosphere tank, a fifth operation of supplying the sample atmosphere in the second sample atmosphere tank to the third chemical sensor unit, and a sixth operation of exhausting the sample atmosphere in the second sample atmosphere tank.

[0073] The second specimen atmosphere tank 20 is connected to the first chemical sensor 2, and a fourth valve 8 is provided between the first chemical sensor 2 and the second specimen atmosphere tank 20. When the first valve 5 is opened, the fourth valve 8 is closed. When the fourth valve 8 is opened, the first valve 5 is closed. This allows a specimen atmosphere to be newly collected in the second specimen atmosphere tank 20 while another specimen atmosphere is being inspected in the second chemical sensor unit 4, and the next inspection can be performed by the first chemical sensor 2. Conversely, while a specimen atmosphere is being inspected (sensed) in the third chemical sensor unit 21, another specimen atmosphere can be newly collected in the first specimen atmosphere tank 3, and the next inspection can be performed by the first chemical sensor 2. This shortens the inspection cycle time in the chemical sensor system 1000 according to this embodiment. Note that the fourth valve 8 is closed when the specimen atmosphere is taken into the first specimen atmosphere tank 3.

[0074] The second specimen atmosphere tank 20 has the same specifications as the first specimen atmosphere tank 3 and is equipped with a volume control device (not shown). A valve corresponding to the third valve 7 is also provided between the second specimen atmosphere tank 20 and the third chemical sensor unit 21 (not shown), and further, airtight paths and valves corresponding to the airtight path 11 and the second valve 6 are also connected to the second specimen atmosphere tank 20 (not shown). When collecting the specimen atmosphere in the second specimen atmosphere tank 20, the same operation as when collecting it in the first specimen atmosphere tank 3 can be performed, and in this case, the first valve 5 is closed and the fourth valve 8 is opened.

[0075] The second determination circuit 14 described above is also connected to the output of the third chemical sensor 21. The second determination circuit 14 analyzes the output signals of the third chemical sensor in addition to the second chemical sensor, and determines whether the target substance is contained in a specified amount or more in the sample atmosphere tested by the second chemical sensor or the third chemical sensor after the test result of the first chemical sensor is positive.

[0076] The second determination circuit 14 can store the time when the second and third chemical sensors tested the sample atmosphere and the test results. It can also record the time when the sample atmosphere was collected at an intake port such as the intake port 1, and the test results of the first and second chemical sensors 2 and 2, or the test results of the first and third chemical sensors, in association with each other. This allows the sample atmosphere to be synchronized with the sample atmosphere tested by the first and second chemical sensors 2 and 2, or the sample atmosphere to be synchronized with the sample atmosphere tested by the first and third chemical sensors 2 and 3, allowing for accurate management of the test results of the sample atmosphere.

[0077] The third chemical sensor unit 21, the second specimen atmosphere tank 20, and the volume control device (not shown) also perform the same operations as the above operations 1 to 7. However, the first control circuit 9 exclusively controls the system consisting of the second chemical sensor unit 4, the first specimen atmosphere tank 3, and the volume control device 103 and the system consisting of the third chemical sensor unit 21, the second specimen atmosphere tank 20, and the volume control device (not shown) so that they do not simultaneously perform operations 1 to 3. The first control circuit 9 controls operations 4 to 7 of one system independently of operations 4 to 7 of the other system.

[0078] Here, the second specimen atmosphere tank and the third chemical sensor unit, which have the same configuration as the first specimen atmosphere tank and the second chemical sensor unit, have been used as an example, but it is also possible to add more sets of specimen atmosphere tanks and chemical sensor units with similar configurations.

[0079] The chemical sensor system according to the first embodiment includes a first chemical sensor, a second chemical sensor unit, and a first sample atmosphere tank located between the first chemical sensor and the second chemical sensor unit, and has an air supply mechanism that performs a first operation of supplying sample atmosphere from the first chemical sensor to the first sample atmosphere tank, a second operation of supplying sample atmosphere from the first sample atmosphere tank to the second chemical sensor unit, and a third operation of exhausting the sample atmosphere from the first sample atmosphere tank, thereby enabling detection of a target substance with high accuracy and responsiveness.

[0080] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0081] The invention according to the embodiment will be described below.

[0082] [1] a first chemical sensor; a second chemical sensor unit; a first specimen atmosphere tank located between the first chemical sensor and the second chemical sensor unit; a first operation of supplying a specimen atmosphere from the first chemical sensor to the first specimen atmosphere tank; a second operation of supplying the specimen atmosphere from the first specimen atmosphere tank to the second chemical sensor unit; and a third operation of exhausting the specimen atmosphere from the first specimen atmosphere tank.

[0083] [2] the second chemical sensor unit includes a mechanism for exposing the sample atmosphere to a sensing solution; The chemical sensor system according to [1], further comprising: a second chemical sensor that detects a substance contained in the sensing solution to which the sample atmosphere is exposed.

[0084] [3] The chemical sensor system according to [1] or [2], wherein the first chemical sensor is a gas phase sensor.

[0085] [4] The chemical sensor system according to [2], wherein the second chemical sensor is a liquid-phase sensor.

[0086] [5] The chemical sensor system according to any one of [1] to [4], further comprising a valve positioned between the first specimen atmosphere tank and the second chemical sensor unit.

[0087] [6] The chemical sensor system according to [5], wherein the valve is opened or closed based on the inspection result of the first chemical sensor.

[0088] [7] The chemical sensor system according to any one of [1] to [6], wherein the first chemical sensor has an intake port for collecting the sample atmosphere.

[0089] [8] The chemical sensor system according to [7], wherein the time when the sample atmosphere is collected at the intake port and the test results of the first chemical sensor and the second chemical sensor are linked and recorded.

[0090] [9] The chemical sensor system according to any one of [1] to [8], wherein the sample atmosphere passes through the first chemical sensor and is collected in the first sample atmosphere tank.

[0091]

[10] a third chemical sensor unit; a second specimen atmosphere tank located between the first chemical sensor and the third chemical sensor unit, a fourth operation of supplying a sample atmosphere to be inspected by the first chemical sensor to the second sample atmosphere tank; a fifth operation of supplying the sample atmosphere in the second sample atmosphere tank to the third chemical sensor unit; A chemical sensor system according to any one of [1] to [9], further comprising an air supply mechanism that performs a sixth operation of exhausting the specimen atmosphere in the second specimen atmosphere tank.

[0092]

[11] the third chemical sensor unit includes a mechanism for exposing the sample atmosphere to a sensing solution; The chemical sensor system according to

[10] , further comprising: a third chemical sensor that detects a substance contained in the sensing solution to which the sample atmosphere is exposed.

[0093]

[12] The chemical sensor system according to

[11] , wherein the third chemical sensor is a liquid-phase sensor.

[0094]

[13] The chemical sensor system according to any one of

[10] to

[12] , further comprising a valve positioned between the second specimen atmosphere tank and the third chemical sensor unit.

[0095]

[14] The chemical sensor system according to

[13] , wherein the valve is opened or closed based on the inspection result of the first chemical sensor.

[0096]

[15] The chemical sensor system according to any one of

[10] to

[14] , wherein the first chemical sensor has an intake port for collecting the sample atmosphere.

[0097]

[16] The chemical sensor system according to

[15] , wherein the time when the sample atmosphere is collected at the intake port and the test results of the first chemical sensor and the third chemical sensor are linked and recorded.

[0098]

[17] The chemical sensor system according to any one of

[10] to

[16] , wherein the sample atmosphere passes through the first chemical sensor and is collected in the second sample atmosphere tank.

[0099]

[18] A chemical sensor system described in any one of [1] to

[17] , wherein when the first chemical sensor does not respond, the pre-gas supply mechanism is controlled to exhaust the sample atmosphere in the first sample atmosphere tank.

[0100]

[19] A chemical sensor system according to any one of [1] to

[17] , wherein when the first chemical sensor responds, the gas supply mechanism is controlled to supply the sample atmosphere from the first sample atmosphere tank to the second chemical sensor unit.

[0101]

[20] The chemical sensor system according to any one of [2] to

[19] , wherein the gas supply mechanism is controlled so that after the sample atmosphere is supplied to the second chemical sensor unit, the second chemical sensor senses the sample atmosphere, and another sample atmosphere is supplied from the first chemical sensor to the first sample atmosphere tank. [Explanation of symbols]

[0102] 1000... Chemical sensor system, 1... Intake port, 2... First chemical sensor, 3... Sample atmosphere tank, 4... Second chemical sensor unit, 9... First control circuit, 13... First control circuit, 14... Second determination circuit, 200... First chemical sensor, 530... Second chemical sensor

Claims

1. a first chemical sensor; a second chemical sensor unit; a first specimen atmosphere tank located between the first chemical sensor and the second chemical sensor unit; an air supply mechanism that performs a first operation of supplying a specimen atmosphere from the first chemical sensor to the first specimen atmosphere tank, a second operation of supplying the specimen atmosphere from the first specimen atmosphere tank to the second chemical sensor unit, and a third operation of exhausting the specimen atmosphere from the first specimen atmosphere tank; the second chemical sensor unit includes a mechanism for exposing the sample atmosphere to a sensing solution; a second chemical sensor that responds to a target substance contained in the sensing solution to which the sample atmosphere is exposed; a valve located between the first analyte atmosphere tank and the second chemical sensor unit, the first chemical sensor is a gas phase sensor; The chemical sensor system, wherein the second chemical sensor is a liquid-phase sensor.

2. 2. The chemical sensor system according to claim 1, wherein the valve is opened or closed based on an inspection result of the first chemical sensor.

3. 2. The chemical sensor system of claim 1, wherein the first chemical sensor has an inlet for collecting the analyte atmosphere.

4. The chemical sensor system according to claim 3 , wherein the time when the sample atmosphere is collected at the intake port and the test results of the first chemical sensor and the second chemical sensor are recorded in association with each other.

5. 2. The chemical sensor system of claim 1, wherein the analyte atmosphere is collected in the first analyte atmosphere tank via the first chemical sensor.

6. a first chemical sensor; a second chemical sensor unit; a first specimen atmosphere tank located between the first chemical sensor and the second chemical sensor unit; a chemical sensor system having an air supply mechanism that performs a first operation of supplying a specimen atmosphere from the first chemical sensor to the first specimen atmosphere tank, a second operation of supplying the specimen atmosphere from the first specimen atmosphere tank to the second chemical sensor unit, and a third operation of exhausting the specimen atmosphere from the first specimen atmosphere tank, a third chemical sensor unit; a second specimen atmosphere tank located between the first chemical sensor and the third chemical sensor unit; a fourth operation of supplying a sample atmosphere to be inspected by the first chemical sensor to the second sample atmosphere tank; a fifth operation of supplying the sample atmosphere in the second sample atmosphere tank to the third chemical sensor unit; and a sixth operation of exhausting the specimen atmosphere from the second specimen atmosphere tank.

7. the third chemical sensor unit includes a mechanism for exposing the sample atmosphere to a sensing solution; The chemical sensor system according to claim 6 , further comprising: a third chemical sensor that detects a substance contained in the sensing solution to which the sample atmosphere is exposed.

8. The chemical sensor system of claim 7 , wherein the third chemical sensor is a liquid-phase sensor.

9. The chemical sensor system of claim 6 , further comprising a valve positioned between the second analyte atmosphere tank and the third chemical sensor unit.

10. 10. The chemical sensor system according to claim 9, wherein the valve is opened or closed based on an inspection result of the first chemical sensor.

11. 7. The chemical sensor system of claim 6, wherein the first chemical sensor has an inlet for collecting the analyte atmosphere.

12. The chemical sensor system according to claim 11 , wherein the time when the sample atmosphere is collected at the intake port and the test results of the first chemical sensor and the third chemical sensor are recorded in association with each other.

13. 7. The chemical sensor system of claim 6, wherein the analyte atmosphere is collected in the second analyte atmosphere tank via the first chemical sensor.

14. 2. The chemical sensor system according to claim 1, wherein the air supply mechanism is controlled to exhaust the specimen atmosphere in the first specimen atmosphere tank when the first chemical sensor does not respond.

15. 2. The chemical sensor system according to claim 1, wherein when the first chemical sensor responds, the gas supply mechanism is controlled to supply the sample atmosphere from the first sample atmosphere tank to the second chemical sensor unit.

16. 2. The chemical sensor system of claim 1, wherein the gas supply mechanism is controlled so that after the gas supply mechanism supplies the sample atmosphere to the second chemical sensor unit, the second chemical sensor performs sensing of the sample atmosphere, and another sample atmosphere is supplied from the first chemical sensor to the first sample atmosphere tank.

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