Chemical sensor system

Abstract

To provide a chemical sensor system capable of accurately detecting a target substance.SOLUTION: According to an embodiment, a chemical sensor system comprises a pipeline, an air blower, a graphene chemical sensor, a pressure-insensitive chemical sensor, and a control device. The pipeline is connected to an inspection target. The air blower is provided in the pipeline. The air blower sends a sample gas to a downstream side from the inspection target. The graphene chemical sensor is provided in the pipeline. The graphene chemical sensor is capable of specifically detecting a target substance. The pressure-insensitive chemical sensor is provided in the pipeline. The pressure-insensitive chemical sensor is capable of detecting at least the target substance. The pressure-insensitive chemical sensor does not detect pressure fluctuations. The control device determines whether or not the sample gas contains the target substance on the basis of detection results from the graphene chemical sensor and the pressure-insensitive chemical sensor.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] For example, there is a chemical sensor system that uses a graphene chemical sensor to detect a target substance contained in a sample atmosphere. In such a chemical sensor system, the graphene chemical sensor may detect air pressure fluctuations, which may reduce the detection accuracy of the target substance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-74878 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of an embodiment of the present invention is to provide a chemical sensor system capable of detecting a target substance with high accuracy. [Means for solving the problem]

[0005] According to an embodiment of the present invention, a chemical sensor system includes a conduit, a blower, a graphene chemical sensor, a pressure-insensitive chemical sensor, and a control device. The conduit is connected to a test object. The blower is provided in the conduit. The blower sends a sample gas downstream from the test object. The graphene chemical sensor is provided in the conduit. The graphene chemical sensor is capable of specifically detecting a target substance. The pressure-insensitive chemical sensor is provided in the conduit. The pressure-insensitive chemical sensor is capable of detecting at least the target substance. The pressure-insensitive chemical sensor does not detect atmospheric pressure fluctuations. The control device determines whether the target substance is included in the sample gas based on detection results of the graphene chemical sensor and the pressure-insensitive chemical sensor. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram illustrating a chemical sensor system according to a first embodiment. [Figure 2] 2(a) and 2(b) are explanatory diagrams schematically illustrating the graphene chemical sensor of the chemical sensor system according to the first embodiment. [Figure 3] 4 is a table showing an example of determination by the chemical sensor system according to the first embodiment. [Figure 4] 4 is a flowchart illustrating an example of the operation of the chemical sensor system according to the first embodiment. [Figure 5] 5(a) and 5(b) are graphs showing the detection results of the graphene chemical sensor and the pressure-insensitive chemical sensor in the experimental example. [Figure 6] FIG. 10 is a block diagram illustrating a chemical sensor system according to a second embodiment. [Figure 7] 7(a) and 7(b) are tables showing examples of determinations made by the chemical sensor system according to the second embodiment. [Figure 8] 10 is a flowchart illustrating an example of the operation of the chemical sensor system according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and in each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0008] (First embodiment) FIG. 1 is a block diagram showing a chemical sensor system according to the first embodiment. 2(a) and 2(b) are explanatory diagrams schematically illustrating the graphene chemical sensor of the chemical sensor system according to the first embodiment. 1, the chemical sensor system 100 according to the first embodiment includes a pipeline 10, a blower 20, a graphene chemical sensor 30, a pressure-insensitive chemical sensor 40, and a control device 50. The chemical sensor system 100 determines whether or not a target substance is contained in a sample gas sent downstream through the pipeline 10 from a test object 1.

[0009] The conduit 10 is connected to the test object 1. The conduit 10 is, for example, a hollow hose. The test object 1 is, for example, a box containing an item. A collection port 11 is provided at the upstream end of the conduit 10. A blower 20, a graphene chemical sensor 30, and a pressure-insensitive chemical sensor 40 are provided in the conduit 10.

[0010] Air blower 20 sends specimen gas downstream from test object 1. The specimen gas includes, for example, the air inside test object 1. Air blower 20 may be, for example, a pump or a fan. In FIG. 1, the arrows indicate the flow of specimen gas when air blower 20 is activated.

[0011] The graphene chemical sensor 30 can specifically detect a target substance. The graphene chemical sensor 30 is provided, for example, upstream of the air blower 20. The graphene chemical sensor 30 is electrically connected to the control device 50. The graphene chemical sensor 30 outputs a detection result to the control device 50.

[0012] 2(a), the graphene chemical sensor 30 has, for example, a GFET (graphene field effect transistor) structure. A surface 30a of the graphene chemical sensor 30 includes graphene. The graphene chemical sensor 30 has, for example, a substrate 37, graphene 32 supported on the substrate 37, a first electrode 35, and a second electrode 36.

[0013] The substrate 37 is, for example, a silicon substrate. The graphene 32 is provided on the substrate 37 via, for example, an underlayer 38. The underlayer 38 may be, for example, a silicon oxide film. The underlayer 38 may also function as a chemical catalyst for forming the graphene 32.

[0014] A first electrode 35 is connected to one end of the graphene 32, and a second electrode 36 is connected to the other end of the graphene 32. One of the first electrode 35 and the second electrode 36 functions as a drain electrode, and the other functions as a source electrode. The first electrode 35 and the second electrode 36 are electrically connected to the graphene 32. A current (drain current) flows between the first electrode 35 and the second electrode 36 through the graphene 32.

[0015] 2(b), a probe molecule 33 is disposed on the surface 30a of the graphene chemical sensor 30. Disposing the probe molecule 33 on the surface 30a of the graphene chemical sensor 30 means that the probe molecule 33 is bound, adsorbed, or brought into close proximity to the surface 30a of the graphene chemical sensor 30 by chemical or charge attraction, π-π interaction, cation-π interaction, hydrophobic interaction, or the like, and the probe molecule 33 is confined to the surface 30a of the graphene chemical sensor 30. The probe molecule 33 can be any substance that exhibits binding to a target substance, such as a protein, a peptide, an antibody, a DNA aptamer, or a derivative thereof.

[0016] When probe molecule 33 recognizes or captures a target substance, the target substance approaches the surface of graphene 32, and the charge of the target substance or the structural change of probe molecule 33 caused by capturing the target substance changes the electronic state of graphene 32. By detecting this as a change in the current (drain current) flowing between first electrode 35 and second electrode 36, the presence and concentration of the target substance in the sample gas can be determined.

[0017] The pressure-insensitive chemical sensor 40 is capable of detecting at least a target substance. The pressure-insensitive chemical sensor 40 does not detect changes in atmospheric pressure. The pressure-insensitive chemical sensor 40 is provided, for example, downstream of the blower device 20. The pressure-insensitive chemical sensor 40 is electrically connected to the control device 50. The pressure-insensitive chemical sensor 40 outputs the detection result to the control device 50.

[0018] The pressure-insensitive chemical sensor 40 can, for example, nonspecifically detect a target substance. The pressure-insensitive chemical sensor 40 can, for example, detect not only the target substance but also impurities such as odor molecules other than the target substance. The pressure-insensitive chemical sensor 40 is, for example, an odor sensor. The pressure-insensitive chemical sensor 40 is, for example, a metal oxide sensor. The pressure-insensitive chemical sensor 40 chemically adsorbs odor molecules and detects the odor molecules based on the weight of the adsorbed substance, changes in frequency, changes in potential, changes in resistivity, etc.

[0019] The control device 50 determines whether or not the sample gas contains a target substance based on the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40. The determination will be described later.

[0020] The chemical sensor system 100 may further include an alarm device 55. The alarm device 55 may, for example, notify the determination result as to whether or not the sample gas contains a target substance. The alarm device 55 is electrically connected to the control device 50. The control device 50 may, for example, output the determination result to the alarm device 55. The alarm device 55 may, for example, visually notify the determination result using text or light, or may audibly notify the determination result using sound. In this manner, the control device 50 may notify the determination result using the alarm device 55. Furthermore, as will be described later, when the detection result of the graphene chemical sensor 30 is estimated to be affected by atmospheric pressure fluctuations, the control device 50 may, through the alarm device 55, notify the fact that the detection result of the graphene chemical sensor 30 is affected by atmospheric pressure fluctuations. The alarm device 55 is provided as needed and may be omitted.

[0021] The determination made by the control device 50 will be described below. 3 is a table showing an example of a determination made by the chemical sensor system according to the first embodiment. This determination is applied, for example, when the atmospheric pressure fluctuation and the target substance do not exist simultaneously, and when the atmospheric pressure fluctuation and the impurities do not exist simultaneously. FIG. 4 is a flowchart showing an example of the operation of the chemical sensor system according to the first embodiment. As shown in FIG. 3, the control device 50 determines that the sample gas contains a target substance when, for example, the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 indicate a detection. A detection indicates, for example, that the signal intensity, fluctuation value, or differential integral value output by the sensor exceeds a threshold. The type of signal output by the sensor is not particularly specified, but may be, for example, a current value, a voltage value, or a value obtained by scanning these values. The control device 50 determines that the sample gas does not contain a target substance when, for example, at least one of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 indicates no detection.

[0022] More specifically, as shown in FIG. 4, if the graphene chemical sensor 30 detects a substance (step S101: Yes) and the pressure-insensitive chemical sensor 40 detects a substance (step S102: Yes), the control device 50 determines that the sample gas contains a target substance (step S103).

[0023] If graphene chemical sensor 30 detects a substance (step S101: Yes) and pressure-insensitive chemical sensor 40 does not detect a substance (step S102: No), control device 50 determines that the sample gas does not contain the target substance (step S104). At this time, control device 50 determines that the detection result of graphene chemical sensor 30 is affected by atmospheric pressure fluctuations. Control device 50 notifies, via alarm device 55, that the detection result of graphene chemical sensor 30 is affected by atmospheric pressure fluctuations (step S105). Step S105 is performed as needed and can be omitted.

[0024] If graphene chemical sensor 30 does not detect a target substance (step S101: No) and pressure-insensitive chemical sensor 40 detects a target substance (step S106: Yes), control device 50 determines that the sample gas does not contain the target substance (step S107). At this time, control device 50 determines that the detection result of pressure-insensitive chemical sensor 40 includes the influence of impurities. Control device 50 may notify, via alarm device 55, that the detection result of pressure-insensitive chemical sensor 40 includes the influence of impurities.

[0025] If the graphene chemical sensor 30 does not detect a target substance (step S101: No) and the pressure-insensitive chemical sensor 40 does not detect a target substance (step S106: No), the control device 50 determines that the sample gas does not contain the target substance (step S108).

[0026] In this way, the control device 50 can determine whether or not the sample gas contains a target substance based on the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40. Furthermore, the control device 50 can estimate, based on the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40, that the detection result of the graphene chemical sensor 30 includes the influence of air pressure fluctuations. Furthermore, the control device 50 can estimate, based on the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40, that the detection result of the pressure-insensitive chemical sensor 40 includes the influence of impurities.

[0027] The following describes the effects of the chemical sensor system 100 according to the first embodiment. The graphene chemical sensor 30 can specifically detect a target substance, but may also detect atmospheric pressure fluctuations. Therefore, when the graphene chemical sensor 30 detects a substance, it is difficult to determine whether the detection result of the graphene chemical sensor 30 is due to the detection of a target substance or due to atmospheric pressure fluctuations. In other words, there is a problem in that the detection result of the graphene chemical sensor 30 is likely to include erroneous detections (false positives) due to the influence of atmospheric pressure fluctuations.

[0028] In contrast, the chemical sensor system 100 according to the first embodiment includes, in addition to the graphene chemical sensor 30, a pressure-insensitive chemical sensor 40 that can detect at least a target substance but does not detect atmospheric pressure fluctuations. The control device 50 determines whether the sample gas contains a target substance based on the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40. This allows the control device 50 to determine whether the sample gas contains a target substance if, for example, the graphene chemical sensor 30 detects a substance but the pressure-insensitive chemical sensor 40 does not. This eliminates false positives (i.e., false positives) caused by atmospheric pressure fluctuations in the graphene chemical sensor 30. This allows the target substance to be detected more accurately than when determining whether the sample gas contains a target substance based solely on the detection results of the graphene chemical sensor 30.

[0029] Furthermore, in the chemical sensor system 100 according to the first embodiment, the graphene chemical sensor 30 is provided upstream of the air blower 20, and the pressure-insensitive chemical sensor 40 is provided downstream of the air blower 20. By providing the graphene chemical sensor 30 upstream of the air blower 20, it is possible to prevent the sample gas from being blown toward the graphene chemical sensor 30 from the air blower 20. This reduces the influence of air pressure fluctuations due to air blowing on the graphene chemical sensor 30. Air pressure fluctuations due to air blowing can be caused by the closing and opening of the conduit 10, the on / off or pulsation of the air blower 20, misalignment of the air blowing angle or position relative to the sensor, and the like. Furthermore, by providing the pressure-insensitive chemical sensor 40 downstream of the air blower 20, it is possible to make the pressure-insensitive chemical sensor 40 have an open system structure. An open system refers to a configuration in which the sensor surface can come into contact with gas outside the conduit 10. This more reliably prevents the pressure-insensitive chemical sensor 40 from detecting changes in atmospheric pressure. Furthermore, since the graphene chemical sensor 30 is provided upstream of the pressure-insensitive chemical sensor 40, it is possible to prevent many target substances from being captured by the pressure-insensitive chemical sensor 40, resulting in the graphene chemical sensor 30 not detecting the target substances, or to prevent odor molecules and the like captured by the pressure-insensitive chemical sensor 40 from detaching and adhering to the graphene chemical sensor 30. It is possible to prevent odor molecules and the like captured by the pressure-insensitive chemical sensor 40 from being re-captured by the pressure-insensitive chemical sensor 40 after detaching. This allows for more accurate detection of target substances.

[0030] Furthermore, in the chemical sensor system 100 according to the first embodiment, the control device 50 determines that the sample gas contains a target substance when both the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 detect a substance, and determines that the sample gas does not contain a target substance when at least one of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 does not detect a substance. This allows for a more reliable determination of whether or not the sample gas contains a target substance. This allows for more accurate detection of the target substance.

[0031] Furthermore, in the chemical sensor system 100 according to the first embodiment, when graphene chemical sensor 30 detects a substance and pressure-insensitive chemical sensor 40 does not detect a substance, control device 50 determines that the sample gas does not contain a target substance and notifies, via alarm device 55, that the detection result of graphene chemical sensor 30 is affected by atmospheric pressure fluctuations. This makes it possible to notify when it is estimated that the graphene chemical sensor 30 contains a false detection (i.e., a false positive) due to the effect of atmospheric pressure fluctuations.

[0032] In the chemical sensor system 100 according to the first embodiment, the pressure-insensitive chemical sensor 40 can, for example, nonspecifically detect a target substance. The pressure-insensitive chemical sensor 40 is, for example, a metal oxide sensor. Such a sensor can nonspecifically detect a target substance without detecting changes in atmospheric pressure.

[0033] (Experimental example) 5(a) and 5(b) are graphs showing the detection results of the graphene chemical sensor and the pressure-insensitive chemical sensor in the experimental example. Fig. 5(a) shows the detection results of the graphene chemical sensor 30 in the experimental example. The horizontal axis of Fig. 5(a) represents time, and the vertical axis of Fig. 5(a) represents current value. Figure 5(b) shows the detection results of the pressure-insensitive chemical sensor 40 in the experimental example. The horizontal axis of Figure 5(b) represents time, and the vertical axis of Figure 5(b) represents voltage. In this example, the output value is an amplified value of the decrease (difference) in the sensor resistance value detected by a bridge circuit or the like. Therefore, an increase in voltage represents a decrease in the sensor resistance.

[0034] In the experimental example, during period P1, a specimen gas containing impurities but not a target substance was used as a sample, and the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 were obtained. Furthermore, during periods P2 and P4, air pressure fluctuations were generated, and the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 were obtained. Furthermore, during period P3, a specimen gas containing impurities and a target substance was used as a sample, and the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 were obtained. In the experimental example, tropane was used as the target substance.

[0035] 5(a), when a specimen gas containing impurities but not a target substance was used as a sample (period P1), the graphene chemical sensor 30 did not show a decrease in current value, resulting in "no detection." On the other hand, when an air pressure fluctuation was generated (periods P2 and P4), the graphene chemical sensor 30 showed a decrease in current value, resulting in "detection," just as when a specimen gas containing impurities and a target substance was used as a sample (period P3).

[0036] 5(b), when a sample gas containing impurities but not a target substance was used as a sample (period P1), the pressure-insensitive chemical sensor 40 showed an increase in voltage value, indicating "detection," just as when a sample gas containing impurities and a target substance was used as a sample (period P3). On the other hand, when an air pressure fluctuation was generated (periods P2 and P4), the pressure-insensitive chemical sensor 40 showed no increase in voltage value, indicating "no detection."

[0037] The above suggests that determining whether a sample gas contains a target substance based solely on the graphene chemical sensor 30 would result in a false positive due to atmospheric pressure fluctuations. However, determining whether a sample gas contains a target substance based on the detection results of the pressure-insensitive chemical sensor 40 in addition to the detection results of the graphene chemical sensor 30 would eliminate false positives due to atmospheric pressure fluctuations and enable a more accurate determination of whether a sample gas contains a target substance. In other words, it suggests that the chemical sensor system 100 according to the first embodiment is capable of detecting a target substance with high accuracy.

[0038] (Second embodiment) FIG. 6 is a block diagram showing a chemical sensor system according to the second embodiment. 7(a) and 7(b) are tables showing examples of determinations made by the chemical sensor system according to the second embodiment. This determination is applied, for example, when there is a possibility that atmospheric pressure fluctuations and a target substance exist simultaneously, and when there is a possibility that pressure fluctuations and impurities exist simultaneously. FIG. 8 is a flowchart showing an example of the operation of the chemical sensor system according to the second embodiment. As shown in Fig. 6, the chemical sensor system 200 according to the second embodiment is the same as the chemical sensor system 100 according to the first embodiment, except that it further includes a pressure sensor 60. In Fig. 6, the flow of the sample gas when the blower 20 is operated is indicated by arrows.

[0039] The pressure sensor 60 is capable of detecting variations in atmospheric pressure. The pressure sensor 60 is provided in the pipeline 10. The pressure sensor 60 is provided, for example, upstream of the blower 20 and downstream of the graphene chemical sensor 30. The pressure sensor 60 is electrically connected to the control device 50. The pressure sensor 60 outputs the detection result to the control device 50.

[0040] The control device 50 determines, based on the detection result of the pressure sensor 60, whether or not the detection result of the graphene chemical sensor 30 is affected by the atmospheric pressure fluctuation.

[0041] 7(a) and 7(b), the control device 50 determines that the sample gas contains a target substance when the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 detect a substance and the pressure sensor 60 does not detect a substance. Furthermore, the control device 50 determines that the sample gas does not contain a target substance when both the graphene chemical sensor 30 and the pressure sensor 60 detect a substance and the pressure-insensitive chemical sensor 40 does not detect a substance. Furthermore, the control device 50 determines that the sample gas does not contain a target substance when the graphene chemical sensor 30 and the pressure sensor 60 do not detect a substance.

[0042] More specifically, as shown in FIG. 8, if the graphene chemical sensor 30 detects a substance (step S201: Yes), the pressure-insensitive chemical sensor 40 detects a substance (step S202: Yes), and the pressure sensor 60 detects a substance (step S203: Yes), the control device 50 determines that the sample gas may contain a target substance (step S204).

[0043] If the graphene chemical sensor 30 detects a substance (step S201: Yes), the pressure-insensitive chemical sensor 40 detects a substance (step S202: Yes), and the pressure sensor 60 does not detect a substance (step S203: No), the control device 50 determines that the sample gas contains a target substance (step S205).

[0044] If graphene chemical sensor 30 detects a substance (step S201: Yes), pressure-insensitive chemical sensor 40 does not detect a substance (step S202: No), and pressure sensor 60 detects a substance (step S206: Yes), control device 50 determines that the sample gas does not contain the target substance (step S207). At this time, control device 50 determines that the detection result of graphene chemical sensor 30 includes the influence of atmospheric pressure fluctuations. Control device 50 notifies, via alarm device 55, that the detection result of graphene chemical sensor 30 includes the influence of atmospheric pressure fluctuations (step S208). Step S208 is performed as needed and can be omitted.

[0045] If the graphene chemical sensor 30 detects a substance (step S201: Yes), the pressure-insensitive chemical sensor 40 does not detect a substance (step S202: No), and the pressure sensor 60 does not detect a substance (step S206: No), the control device 50 determines that an abnormal state exists (step S209). This is because if the graphene chemical sensor 30 detects a substance and the pressure sensor 60 does not detect a substance, the target substance is contained in the sample gas, and in this case, the pressure-insensitive chemical sensor 40 should detect a substance. At this time, the control device 50 may notify the alarm device 55 that an abnormal state exists.

[0046] When the graphene chemical sensor 30 does not detect anything (step S201: No), the pressure-insensitive chemical sensor 40 detects anything (step S210: Yes), and the pressure sensor 60 detects anything (step S211: Yes), the control device 50 determines that an abnormal state exists (step S212). This is because when the pressure sensor 60 detects anything, the graphene chemical sensor 30 should also detect anything. At this time, the control device 50 may notify the alarm device 55 that an abnormal state exists.

[0047] If graphene chemical sensor 30 does not detect a target substance (step S201: No), pressure-insensitive chemical sensor 40 detects a target substance (step S210: Yes), and pressure sensor 60 does not detect a target substance (step S211: No), control device 50 determines that the sample gas does not contain the target substance (step S213). At this time, control device 50 determines that the detection result of graphene chemical sensor 30 includes the influence of impurities. At this time, control device 50 notifies, via alarm device 55, that the detection result of pressure-insensitive chemical sensor 40 includes the influence of impurities (step S214). Step S214 is performed as needed and can be omitted.

[0048] When the graphene chemical sensor 30 does not detect anything (step S201: No), the pressure-insensitive chemical sensor 40 does not detect anything (step S210: No), and the pressure sensor 60 detects anything (step S215: Yes), the control device 50 determines that an abnormal state exists (step S216). This is because when the pressure sensor 60 detects anything, the graphene chemical sensor 30 should also detect anything. At this time, the control device 50 may notify the alarm device 55 that an abnormal state exists.

[0049] If the graphene chemical sensor 30 does not detect anything (step S201: No), the pressure-insensitive chemical sensor 40 does not detect anything (step S210: No), and the pressure sensor 60 detects anything (step S215: No), the control device 50 determines that the sample gas does not contain the target substance (step S217).

[0050] In this way, the control device 50 can determine whether the sample gas contains a target substance based on the detection results of the graphene chemical sensor 30, the pressure-insensitive chemical sensor 40, and the pressure sensor 60. Furthermore, the control device 50 can estimate, based on the detection results of the graphene chemical sensor 30, the pressure-insensitive chemical sensor 40, and the pressure sensor 60, that the detection result of the graphene chemical sensor 30 is affected by atmospheric pressure fluctuations. Furthermore, the control device 50 can estimate, based on the detection results of the graphene chemical sensor 30, the pressure-insensitive chemical sensor 40, and the pressure sensor 60, that the detection result of the pressure-insensitive chemical sensor 40 is affected by impurities. Furthermore, the control device 50 can estimate, based on the detection results of the graphene chemical sensor 30, the pressure-insensitive chemical sensor 40, and the pressure sensor 60, that an abnormal state exists. An abnormal state in this case may be a leak in the pipeline, causing a gas other than the sample gas to flow in or a pressure abnormality.

[0051] The following describes the effects of the chemical sensor system 200 according to the second embodiment. For example, a case will be described in which it is determined whether or not a target substance is contained in a sample gas based on the detection results of graphene chemical sensor 30 and pressure-insensitive chemical sensor 40. When graphene chemical sensor 30 detects something and pressure-insensitive chemical sensor 40 does not detect something, there are five possible cases where both air pressure fluctuation and a target substance may be present at the same time, and where both pressure fluctuation and impurities may be present at the same time. Pattern 1: Target substance present, no pressure fluctuations, no impurities Pattern 2: Target substance present, atmospheric pressure fluctuations, no impurities Pattern 3: Target substance present, no pressure fluctuation, impurities present Pattern 4: Target substance present, atmospheric pressure fluctuations, and impurities present Pattern 5: No target substance, pressure fluctuations, impurities In this way, if the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 detect a target substance and determine that the sample gas contains the target substance, there is a risk that, as in pattern 5, the sample gas may not actually contain the target substance despite being determined to contain the target substance (i.e., a false positive).

[0052] In contrast, the chemical sensor system 200 according to the second embodiment includes a pressure sensor 60 capable of detecting atmospheric pressure fluctuations in addition to the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40. The control device 50 determines whether the sample gas contains a target substance based on the detection results of the graphene chemical sensor 30, the pressure-insensitive chemical sensor 40, and the pressure sensor 60. This allows, for example, a determination to be made that there is no atmospheric pressure fluctuation when the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 detect a target substance but the pressure sensor 60 does not. This eliminates false positives (i.e., false positives) caused by atmospheric pressure fluctuations in the graphene chemical sensor 30. This allows for more accurate detection of the target substance than when determining whether the sample gas contains a target substance based solely on the detection results of the graphene chemical sensor 30. Furthermore, this allows for more accurate detection of the target substance than when determining whether the sample gas contains a target substance based solely on the detection results of the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40.

[0053] Furthermore, in the chemical sensor system 200 according to the second embodiment, the control device 50 determines that the sample gas may contain a target substance when the graphene chemical sensor 30 and the pressure-insensitive chemical sensor 40 indicate a detection, and when the pressure sensor 60 indicates a detection. In this case, the sample gas may not contain the target substance, and the detection result may include the effects of both impurities and atmospheric pressure fluctuations.

[0054] Furthermore, in the chemical sensor system 200 according to the second embodiment, the pressure sensor 60 is provided upstream of the air blower 20 and downstream of the graphene chemical sensor 30. By providing the pressure sensor 60 upstream of the air blower 20, it is possible to prevent the sample gas from being blown from the air blower 20 toward the pressure sensor 60. This reduces the influence of air pressure fluctuations on the pressure sensor 60 due to the air blowing. Furthermore, by providing the pressure sensor 60 downstream of the graphene chemical sensor 30, it is possible to easily detect air pressure fluctuations on the graphene chemical sensor 30 using the pressure sensor 60. This makes it possible to more reliably determine whether the detection results of the graphene chemical sensor 30 are influenced by air pressure fluctuations. Therefore, the target substance can be detected with higher accuracy.

[0055] Furthermore, in the chemical sensor system 200 according to the second embodiment, when the graphene chemical sensor 30 detects, the pressure-insensitive chemical sensor 40 does not detect, and the pressure sensor 60 detects, the control device 50 determines that the sample gas does not contain the target substance, and determines that only air pressure fluctuations are present, and can report this. Furthermore, when the graphene chemical sensor 30 does not detect, and the pressure sensor 60 does not detect, the control device 50 determines that the sample gas does not contain the target substance. In this case, when the pressure-insensitive chemical sensor 40 detects, the control device 50 determines that the detection result includes the influence of impurities, and can report this. This allows for more reliable determination of whether the sample gas contains the target substance. Therefore, the target substance can be detected with greater accuracy.

[0056] Furthermore, in the chemical sensor system 200 according to the second embodiment, the graphene chemical sensor 30 is provided upstream of the blower 20, and the pressure-insensitive chemical sensor 40 is provided downstream of the blower 20, thereby reducing the effect of air pressure fluctuations on the graphene chemical sensor 30 and more reliably preventing the pressure-insensitive chemical sensor 40 from detecting air pressure fluctuations, thereby enabling more accurate detection of the target substance.

[0057] Also in the chemical sensor system 200 according to the second embodiment, the pressure-insensitive chemical sensor 40 can, for example, nonspecifically detect a target substance. The pressure-insensitive chemical sensor 40 is, for example, a metal oxide sensor. Such a sensor can nonspecifically detect a target substance without detecting atmospheric pressure fluctuations.

[0058] Embodiments may include the following features.

[0059] (Configuration 1) A pipeline connected to the inspection object; a blower provided in the pipeline for blowing the sample gas downstream from the test object; a graphene chemical sensor provided in the pipeline and capable of specifically detecting a target substance; a pressure-insensitive chemical sensor that is provided in the pipeline and is capable of detecting at least the target substance but does not detect changes in atmospheric pressure; a control device that determines whether the target substance is contained in the sample gas based on detection results of the graphene chemical sensor and the pressure-insensitive chemical sensor; and A chemical sensor system comprising:

[0060] (Configuration 2) the graphene chemical sensor is provided upstream of the blower; 2. The chemical sensor system according to claim 1, wherein the pressure-insensitive chemical sensor is provided downstream of the blower.

[0061] (Configuration 3) The control device determining that the target substance is contained in the sample gas when the graphene chemical sensor and the pressure-insensitive chemical sensor detect a substance; 3. The chemical sensor system according to claim 1, wherein the target substance is determined not to be contained in the sample gas when at least one of the graphene chemical sensor and the pressure-insensitive chemical sensor does not detect any substance.

[0062] (Configuration 4) Further provided with an alarm device, The chemical sensor system of configuration 3, wherein the control device determines that the sample gas does not contain the target substance when the graphene chemical sensor detects a substance and the pressure-insensitive chemical sensor does not detect a substance, and notifies the alarm device that the detection result of the graphene chemical sensor is affected by atmospheric pressure fluctuations.

[0063] (Configuration 5) 5. The chemical sensor system according to any one of configurations 1 to 4, wherein the pressure-insensitive chemical sensor is capable of non-specifically detecting the target substance.

[0064] (Configuration 6) 6. The chemical sensor system of claim 5, wherein the pressure-insensitive chemical sensor is a metal oxide sensor.

[0065] (Configuration 7) a pressure sensor provided in the pipeline and capable of detecting atmospheric pressure fluctuations; The chemical sensor system of any one of configurations 1 to 6, wherein the control device determines whether the sample gas contains the target substance based on the detection results of the graphene chemical sensor, the pressure-insensitive chemical sensor, and the pressure sensor.

[0066] (Configuration 8) 8. The chemical sensor system according to claim 7, wherein the pressure sensor is provided upstream of the blower and downstream of the graphene chemical sensor.

[0067] (Configuration 9) a pressure sensor provided in the pipeline and capable of detecting atmospheric pressure fluctuations; The control device determining that the target substance is contained in the sample gas when the graphene chemical sensor and the pressure-insensitive chemical sensor detect a substance and the pressure sensor does not detect a substance; The chemical sensor system according to any one of configurations 1, 2, 5, and 6, wherein when at least one of the graphene chemical sensor and the pressure-insensitive chemical sensor does not detect anything, it is determined that the target substance is not contained in the sample gas.

[0068] As described above, according to the embodiment, it is possible to provide a chemical sensor system capable of detecting a target substance with high accuracy.

[0069] 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. [Explanation of symbols]

[0070] 1: Test subject 10: Conduit 11:Collection port 20: Air blower 30: Graphene chemical sensor 40: Pressure-insensitive chemical sensor 50: Control device 55: Alarm device 60: Pressure sensor 100, 200: Chemical sensor system

Claims

1. A pipeline connected to the inspection object; a blower provided in the pipeline for blowing the sample gas downstream from the test object; a graphene chemical sensor provided in the pipeline and capable of specifically detecting a target substance; a pressure-insensitive chemical sensor that is provided in the pipeline and is capable of detecting at least the target substance but does not detect changes in atmospheric pressure; a control device that determines whether the target substance is contained in the sample gas based on detection results of the graphene chemical sensor and the pressure-insensitive chemical sensor; and A chemical sensor system comprising:

2. the graphene chemical sensor is provided upstream of the blower; The chemical sensor system of claim 1 , wherein the pressure-insensitive chemical sensor is provided downstream of the blower.

3. The control device determining that the target substance is contained in the sample gas when the graphene chemical sensor and the pressure-insensitive chemical sensor detect a substance; The chemical sensor system according to claim 1 , wherein when at least one of the graphene chemical sensor and the pressure-insensitive chemical sensor does not detect anything, it is determined that the target substance is not contained in the sample gas.

4. Further provided with an alarm device, 4. The chemical sensor system of claim 3, wherein the control device determines that the sample gas does not contain the target substance when the graphene chemical sensor detects a substance and the pressure-insensitive chemical sensor does not detect a substance, and notifies the alarm device that the detection result of the graphene chemical sensor is affected by atmospheric pressure fluctuations.

5. The chemical sensor system of claim 1 , wherein the pressure-insensitive chemical sensor is capable of non-specifically detecting the target substance.

6. The chemical sensor system of claim 5 , wherein the pressure insensitive chemical sensor is a metal oxide sensor.

7. a pressure sensor provided in the pipeline and capable of detecting atmospheric pressure fluctuations; 7. The chemical sensor system according to claim 1, wherein the control device determines whether the sample gas contains the target substance based on detection results of the graphene chemical sensor, the pressure-insensitive chemical sensor, and the pressure sensor.

8. The chemical sensor system according to claim 7 , wherein the pressure sensor is provided upstream of the blower and downstream of the graphene chemical sensor.

9. a pressure sensor provided in the pipeline and capable of detecting atmospheric pressure fluctuations; The control device determining that the target substance is contained in the sample gas when the graphene chemical sensor and the pressure-insensitive chemical sensor detect a substance and the pressure sensor does not detect a substance; 7. The chemical sensor system according to claim 1, wherein the target substance is determined not to be contained in the sample gas when at least one of the graphene chemical sensor and the pressure-insensitive chemical sensor does not detect any substance.

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