Gas chromatograph mass spectrometry system and gas detection system

Abstract

A gas chromatograph mass spectrometry system (1) is provided with: a column (20) that separates components contained in a sample gas; a mass spectrometer (30) that analyzes the sample gas by ionizing the gas that has passed through the column (20) in a vacuum state; and a switching device (40) that has a first microvalve (200) disposed at a connection portion between the column (20) and the mass spectrometer (30). The first microvalve (200) is provided with: a base part (220) in which an inflow port (223) and an outflow port (224) are formed; and a diaphragm part (230) that is disposed facing the base part (220) and switches, by elastically deforming, between communicating and blocking between the inflow port (223) and the outflow port (224).

Description

Gas chromatograph mass spectrometry system and gas detection system

[0001] The present disclosure relates to a gas chromatography mass spectrometry system and a gas detection system that include a column that temporally separates gas components contained in a sample gas.

[0002] Gas chromatograph / mass spectrometry (GC / MS) is an analytical technique that uses a column to separate the components contained in a sample gas over time, and then ionizes the sample gas that has passed through the column under vacuum using a mass spectrometer (MS) to qualitatively and quantitatively analyze the sample gas. Gas chromatograph / mass spectrometry is highly versatile and is used for a variety of applications.

[0003] Columns used in gas chromatograph mass spectrometers require periodic replacement. For example, one column replacement method uses a capillary tube (see Non-Patent Document 1). This replacement method connects the column outlet to the mass spectrometer via a capillary tube, thereby preventing atmospheric air from entering the mass spectrometer and maintaining a vacuum even when the column is removed.

[0004] Furthermore, if the vacuum system of a mass spectrometer is broken and exposed to the atmosphere during column replacement, it will take a long time for the mass spectrometer to restart and stabilize after column replacement. For this reason, methods have been proposed that allow column replacement without opening the vacuum system of a mass spectrometer to the atmosphere. One example of a column replacement method without opening the vacuum system of a mass spectrometer to the atmosphere is a method in which a dedicated probe is used to attach an O-ring to the column outlet (see Non-Patent Document 2). This replacement method involves lowering the temperature of the ion source and interface of the mass spectrometer, then using a dedicated probe to attach an O-ring to the column outlet to seal the vacuum system of the mass spectrometer, and then manually switching the column flow rate on and off to replace the column.

[0005] "Vent-free GC / MS Adapter: A GC / MS Interface for Rapid Column Replacement," Frontier Labs, Inc. (https: / / www.frontier-lab.com / assets / file / catalogue / Vent-free_J_200303_011202.pdf) "SmartTune izard and easy, vent-free column replacement - two innovations in low-resolution GC-MS technology," Thermo Fisher Scientific (https: / / assets.thermofisher.com / TFS-Assets / CMD / posters / po-10609-gc-ms-innovations-low-resolution-pittcon2018-po10609-en.pdf)

[0006] In the column replacement method using a capillary resistance tube (Non-Patent Document 1), the column outlet is connected to the mass spectrometer via a capillary resistance tube to prevent atmospheric air from entering the mass spectrometer when the column is removed. However, this method does not completely prevent gas from inside the capillary resistance tube from entering the mass spectrometer, and the degree of vacuum in the mass spectrometer still decreases slightly. As a result, there is a problem in that it takes a certain amount of time for the vacuum to stabilize after column replacement before analysis can be performed.

[0007] Furthermore, in a method of replacing a column by using a dedicated probe to attach an O-ring to the column outlet (Non-Patent Document 2), it is possible to replace the column without opening the vacuum system of the mass spectrometer to the atmosphere. However, to replace the column, the user must lower the temperature of the ion source and interface of the mass spectrometer, stop the carrier gas supply, and then seal the vacuum system of the mass spectrometer using an O-ring or the like, which is a very complicated and time-consuming replacement procedure.

[0008] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to enable a column to be replaced with a simple operation in a gas chromatography mass spectrometry system in which gas that has passed through a column is analyzed by a mass spectrometer without reducing the degree of vacuum of the mass spectrometer.

[0009] Another object of the present disclosure is to prevent contamination by impurities in a gas detection system in which gases separated in a column are detected by a detection device.

[0010] Another object of the present disclosure is to provide a gas chromatograph mass spectrometry system in which gas that has passed through a column is analyzed by a mass spectrometer, and to perform highly accurate analysis in the mass spectrometer even when high-temperature gas is supplied to the mass spectrometer.

[0011] A gas chromatograph mass spectrometry system according to the present disclosure includes a column for separating components contained in a sample gas, a mass spectrometer for analyzing the sample gas by ionizing the gas that has passed through the column under vacuum conditions, and a switching device having a first microvalve located at the connection between the column and the mass spectrometer. The first microvalve includes a first base portion having an inlet for introducing gas from the column into the interior and an outlet for discharging the gas introduced from the inlet to the mass spectrometer, and a first diaphragm portion located opposite the first base portion and elastically deforming to switch between communication between the inlet and the outlet.

[0012] The gas detection system according to the present disclosure includes a column for separating components contained in a sample gas, a detection device for detecting the gas separated by the column, and a diverter having a first microvalve and a second microvalve disposed at a connection between the column and the detection device. The first microvalve includes a first base portion formed with an inlet for introducing gas from the column into the first microvalve and an outlet for allowing the gas introduced from the inlet to flow out to the detection device, and a first diaphragm portion disposed opposite the first base portion and elastically deformable to switch between communication between the inlet and the outlet. The second microvalve includes a second base portion formed with a branch port branching from an inlet-side flow path of the first microvalve and an outlet port for discharging the gas introduced from the branch port to the outside of the detection device, and a second diaphragm portion disposed opposite the second base portion and elastically deformable to switch between communication between the branch port and the outlet.

[0013] The gas chromatograph mass spectrometry system according to the present disclosure includes a column for separating components contained in a sample gas, a mass spectrometer for analyzing the sample gas by ionizing the gas that has passed through the column under vacuum conditions, and a switching device having a first microvalve disposed at the connection between the column and the mass spectrometer. The first microvalve is made of single-crystal silicon.

[0014] According to the gas chromatograph mass spectrometry system of the present disclosure, in a gas chromatograph mass spectrometry system in which gas that has passed through a column is analyzed by a mass spectrometer, the column can be replaced with a simple operation without reducing the degree of vacuum of the mass spectrometer.

[0015] According to the gas detection system of the present disclosure, contamination by impurities can be prevented in a gas detection system in which gas separated in a column is detected by a detection device.

[0016] Furthermore, according to another gas chromatograph mass spectrometry system disclosed herein, in a gas chromatograph mass spectrometry system in which gas that has passed through a column is analyzed by a mass spectrometer, even if high-temperature gas is supplied to the mass spectrometer, high-precision analysis can be performed by the mass spectrometer.

[0017] FIG. 1 is a diagram schematically showing an example of the overall configuration of a gas chromatograph mass spectrometry system. FIG. 2 is a cross-sectional view of a first microvalve when the first microvalve is in an open state (communicating state). FIG. 3 is a cross-sectional view of a first microvalve when the first microvalve is in a closed state (blocking state). FIG. 4 is a flowchart showing an example of the procedure for a column replacement operation. FIG. 5 is a diagram (part 1) schematically showing an example of the configuration of an analysis module. FIG. 6 is a diagram showing an example of discharging unnecessary components to the outside of a mass spectrometer using a switching device (diverter). FIG. 7 is a diagram (part 2) schematically showing an example of the configuration of an analysis module. FIG. 8 is a diagram (part 3) schematically showing an example of the configuration of an analysis module.

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0019] 1 is a diagram schematically illustrating an example of the overall configuration of a gas chromatograph mass spectrometry system 1 according to this embodiment. The gas chromatograph mass spectrometry system 1 temporally separates gas components contained in a sample gas using a column, ionizes the gas separated by the column in a vacuum state to obtain a mass spectrum of the gas, and performs mass analysis of the gas from the obtained mass spectrum.

[0020] The gas chromatograph mass spectrometry system 1 includes an analysis module 2, an input device 60, a display device 70, and a control device 100. The analysis module 2 includes an injection port 10, a column 20, a mass spectrometer 30, a rotary pump 31, a switching device 40, a solenoid valve 41, and a flow controller 50.

[0021] The input device 60 is, for example, a keyboard or a pointing device such as a mouse, and receives requests or commands from a user. The requests or commands inputted by the user to the input device 60 are sent to the control device 100.

[0022] The display device 70 is configured by, for example, a liquid crystal display (LCD) panel, and displays information to the user. When a touch panel is used as the user interface, the input device 60 and the display device 70 are integrally formed.

[0023] The control device 100 includes a calculation unit 110, a memory unit 120, an input / output interface, etc. The control device 100 comprehensively controls the entire analysis module 2 and analyzes the sample gas. The control device 100 is connected to an input device 60 and a display device 70, which are user interfaces, via wire or wirelessly. The calculation unit 110 has a calculation device (Central Processing Unit) and uses information stored in the memory unit 120 to control the analysis module 2 and analyze the sample gas.

[0024] As described above, the analysis module 2 includes the injection port 10, the column 20, the mass spectrometer 30, the rotary pump 31, the switching device 40, the solenoid valve 41, and the flow controller 50.

[0025] A carrier gas whose pressure is automatically adjusted by a flow controller 50 is supplied to the injection port 10. When a sample gas to be analyzed is supplied to the injection port 10 from a sample tank (not shown), the sample gas is supplied to the column 20 together with the carrier gas.

[0026] The column 20 separates the components of the sample gas supplied from the injection port 10 in terms of time and supplies them to the mass spectrometer 30 .

[0027] The mass spectrometer 30 analyzes the sample gas by ionizing the components of the sample gas that have passed through the column 20 under vacuum conditions. Specifically, the mass spectrometer 30 includes an ion source, an ion lens, a quadrupole filter, and a detector. The ion source ionizes the components of the sample that have passed through the column 20. The ion lens focuses the ions ionized by the ion source. The quadrupole filter controls an applied voltage to allow only ions with a mass-to-charge ratio determined by the applied voltage to pass. The detector detects ions that have passed through the quadrupole filter. The entire mass spectrometer 30 is housed in a vacuum chamber, and the vacuum system (inside the vacuum chamber) of the mass spectrometer 30 can be evacuated using a rotary pump 31 to increase the degree of vacuum in the vacuum system of the mass spectrometer 30 to a desired level.

[0028] The switching device 40 is disposed at the connection between the column 20 and the mass spectrometer 30. The outlet end of the column 20 is connected to the switching device 40 by a ferrule and a nut. The inlet end of the column 20 is connected to the injection port 10 by a ferrule and a nut. The column 20 can be removed and replaced by loosening the nuts on the inlet and outlet sides of the column 20.

[0029] The switching device 40 has a first microvalve 200 that has an extremely small dead volume and is inactive (allowing the sample to pass directly through). The first microvalve 200 is configured to be switchable between an open state (communicating state) that connects the column 20 and the mass spectrometer 30, and a closed state (blocking state) that blocks the column 20 from the mass spectrometer 30 and seals the vacuum system of the mass spectrometer 30.

[0030] Fig. 2 is a cross-sectional view of the first microvalve 200 when the first microvalve 200 is in an open state (communicating state). Fig. 3 is a cross-sectional view of the first microvalve 200 when the first microvalve 200 is in a closed state (blocking state). An example of the configuration of the first microvalve 200 according to this embodiment will be described with reference to Figs. 2 and 3.

[0031] The first microvalve 200 has a layered structure including a base layer (first base portion) 220, a diaphragm layer (first diaphragm portion) 230, and a cover layer 240, which are layered in this order. Each of the base layer 220, diaphragm layer 230, and cover layer 240 is made of single-crystal silicon and microfabricated using MEMS (Micro Electric Mechanical Systems) technology to achieve the desired strength, flexibility, and inertness.

[0032] The thickness (dimension in the stacking direction) of the first microvalve 200 is approximately 1 to 2 mm. For convenience, in the following description, the direction from the base layer 220 toward the cover layer 240 may be referred to as the upward direction, and the direction from the cover layer 240 toward the base layer 220 may be referred to as the downward direction.

[0033] The base layer 220 is disposed as the bottom layer of the first microvalve 200. The base layer 220 has a recess 221 and openings 222 to 224 formed therein. The recess 221 has a substantially circular shape when the base layer 220 is viewed in plan from above, and is formed near the approximate center of the base layer 220. The recess 221 is recessed from the upper surface side to the lower surface side of the base layer 220. The thickness of the base layer 220 is approximately 150 μm. The depth of the recess 221 is 5 to 20 μm, and preferably approximately 10 μm.

[0034] The openings 223 and 224 are formed in the bottom 225 of the recess 221. As will be described later, the openings 223 and 224 form an inlet and an outlet for the sample gas, respectively. The opening 222 is formed on the outer edge of the base layer 220 around the recess 221, spaced apart from the recess 221. The opening 222 forms a supply port for a control fluid (pneumatic fluid) for the first microvalve 200.

[0035] The diaphragm layer 230 is disposed on the upper surface side of the base layer 220, facing the base layer 220. The diaphragm layer 230 has an opening 232 penetrating the diaphragm layer 230, a rigid portion 234, and a flexible portion 233 provided around the rigid portion 234. The flexible portion 233 is thinner than the rigid portion 234 and is flexible. The flexible portion 233 elastically deforms, causing the rigid portion 234 to displace in the vertical direction.

[0036] The opening 232 is formed at a distance from the flexible portion 233 and the rigid portion 234. When viewed in a plan view from above, the opening 232 is formed at a position overlapping the opening 222 of the base layer 220, and together with the opening 222 forms a supply port for pneumatic fluid.

[0037] The first microvalve 200 is connected to a flow path member (flow path plate) 250 when in use. The flow path member 250 has openings 252 to 254 formed at positions corresponding to the openings 222 to 224 of the base layer 220, respectively. The opening 252 of the flow path member 250, the opening 222 of the base layer 220, and the opening 232 of the diaphragm layer 230 are in communication with each other, forming a supply port 262 for pneumatic fluid. The pneumatic fluid is supplied to the recess 241 of the cover layer 240 through the supply port 262.

[0038] The opening 253 of the flow path member 250 and the opening 223 of the base layer 220 communicate with each other, forming an inlet 263 for the sample gas. The opening 254 of the flow path member 250 and the opening 224 of the base layer 220 communicate with each other, forming an outlet 264 for the sample gas.

[0039] The first microvalve 200 is a so-called normally open type valve, which is in an open state (a communicating state in which the inlet 263 and the outlet 264 are connected) in a normal state in which no pneumatic fluid is supplied to the supply port 262 of the flow path member 250, and is in a closed state (a blocked state in which the inlet 263 and the outlet 264 are blocked) when pneumatic fluid is supplied to the supply port 262 of the flow path member 250.

[0040] The inlet 263 is connected to the outlet end of the column 20. The outlet 264 is connected to the inlet end of the mass spectrometer 30. The supply port 262 is connected to the flow controller 50 via a solenoid valve 41.

[0041] The opening and closing of the first microvalve 200 is controlled by a solenoid valve 41. When the control device 100 closes the solenoid valve 41, no pneumatic fluid is supplied to the supply port 262 of the flow path member 250. In this case, as shown in FIG. 2 , the flexible portion 233 and the rigid portion 234 are maintained in a normal state, spaced apart from the bottom 225 of the recess 221 in the base layer 220, so that the inlet 263 and outlet 264 for the sample gas are connected to each other. In other words, the first microvalve 200 is in an open state (connected state).

[0042] When the control device 100 opens the solenoid valve 41, pneumatic fluid is supplied to the supply port 262 of the flow path member 250. In this case, the flexible portion 233 and the rigid portion 234 are pushed by the pneumatic fluid and displaced downward, so that the lower surfaces of the flexible portion 233 and the rigid portion 234 come into close contact with the bottom 225 of the recess 221 in the base layer 220, thereby blocking the inlet 263 and outlet 264 for the sample gas. In other words, the first microvalve 200 is in a closed state (blocked state). Note that instead of driving (displacing) the flexible portion 233 and the rigid portion 234 with the pneumatic fluid, the flexible portion 233 and the rigid portion 234 may be electrically driven (displaced) using a piezoelectric element or the like.

[0043] [Replacing the Column 20] In general, in a gas chromatograph mass spectrometry system, the column needs to be replaced when it becomes contaminated. Therefore, it is desirable that the column can be replaced by a simple operation by the user without reducing the degree of vacuum in the mass spectrometer.

[0044] To meet these needs, the gas chromatograph mass spectrometry system 1 according to this embodiment is provided with a switching device 40 having a first microvalve 200 with an extremely small dead volume at the connection between the column 20 and the mass spectrometer 30. This allows the procedure required for replacing the column 20 to be preprogrammed in the control device 100 or a server that communicates with the control device 100, thereby simplifying the operation of replacing the column 20 by the user without reducing the degree of vacuum in the mass spectrometer 30.

[0045] 4 is a flowchart showing an example of a procedure for a user to replace the column 20. When the user wants to start replacing the column 20, the user first presses the "Start Column Replacement" button displayed on the display device 70 (step S1). This causes the display device 70 to send a signal to the control device 100 to start replacing the column 20.

[0046] When the control device 100 receives a signal to start replacing the column 20, it controls the solenoid valve 41 to place the first microvalve 200 in the closed state (shutoff state) shown in Figure 3. This seals the vacuum system of the mass spectrometer 30, preventing a decrease in the degree of vacuum in the mass spectrometer 30 even if the column 20 is removed from the first microvalve 200 at this stage. The control device 100 also stops the heater for controlling the temperature of the column 20 and opens the flap of the column oven to cool the column 20.

[0047] When the column 20 has cooled to a preset temperature (e.g., near room temperature), the control device 100 controls the flow controller 50 to stop the supply of carrier gas and displays a message "Column replacement possible" on the display device 70 to notify the user that the column 20 is ready to be replaced (step S2). In this way, the user can make the column 20 ready to be replaced without reducing the degree of vacuum in the mass spectrometer 30 by simply pressing the "Start column replacement" button displayed on the display device 70.

[0048] After the user confirms that the message "Column exchange possible" is displayed on the display device 70, the user actually exchanges the column 20 (step S3).

[0049] After the replacement of the column 20 is completed, the user presses the "Column replacement completed" button displayed on the display device 70 (step S4), which causes the display device 70 to send a signal to the control device 100 indicating that the replacement of the column 20 has been completed.

[0050] When the control device 100 receives a signal indicating that the replacement of the column 20 is complete, it controls the flow controller 50 to resume the supply of carrier gas and controls the solenoid valve 41 to open (communicate) the first microvalve 200. This allows the carrier gas to be supplied again from the replaced column 20 through the first microvalve 200 to the mass spectrometer 30. At this time, gas inside the first microvalve 200 (gas other than the carrier gas) is supplied to the mass spectrometer 30. However, because the dead volume of the first microvalve 200 is extremely small, the amount of gas other than the carrier gas supplied to the mass spectrometer 30 can be kept as low as possible. This allows the column 20 to be replaced without reducing the degree of vacuum in the mass spectrometer 30.

[0051] Furthermore, the control device 100 displays a sign indicating "analysis possible" on the display device 70 or the like to notify the user that analysis is possible.

[0052] As described above, in the gas chromatograph mass spectrometry system 1 according to this embodiment, the switching device 40 having the first microvalve 200 with a minimal dead volume is disposed at the connection between the column 20 and the mass spectrometer 30. The user can then replace the column 20 by simply pressing the "Start column replacement" button, sealing the vacuum system of the mass spectrometer 30 while maintaining the operating state of the mass spectrometer 30. Furthermore, even when the supply of carrier gas is resumed after replacing the column 20, the minimal dead volume of the first microvalve 200 minimizes the amount of gas other than the carrier gas supplied to the mass spectrometer 30. As a result, the user can replace the column 20 with a simple operation without reducing the degree of vacuum in the mass spectrometer 30.

[0053] Furthermore, since the first microvalve 200 is formed from inert single-crystal silicon, even if high-temperature gas is supplied to the mass spectrometer 30 through the first microvalve 200, high-precision analysis can be performed in the mass spectrometer 30.

[0054] Furthermore, since the degree of vacuum in the mass spectrometer 30 does not decrease substantially even after the column 20 is replaced, the time required to raise the degree of vacuum in the mass spectrometer 30 to the desired level and make it ready for analysis after the column 20 is replaced can be significantly reduced.

[0055] Furthermore, by controlling the carrier gas and the first microvalve 200 with the electronic solenoid valve 41 and flow controller 50, the procedure for replacing the column 20 and the procedure for restarting the column after replacement can be automated.

[0056] [Modification 1] Although the switching device 40 according to the above embodiment is an opening / closing device including one microvalve (first microvalve 200), the switching device 40 may be a diverter including two microvalves.

[0057] 5 is a diagram schematically illustrating an example of the configuration of an analysis module 2A according to Modification 1. In the analysis module 2A, the switching device 40 of the analysis module 2 shown in FIG. 1 is replaced with a switching device 40A.

[0058] The switching device 40A is a diverter capable of switching flow paths. The switching device 40A includes a second microvalve 200A in addition to the first microvalve 200 described above. The basic configuration of the second microvalve 200A is the same as that of the first microvalve 200 (see FIGS. 2 and 3). Specifically, like the first microvalve 200, the second microvalve 200A has a layered structure in which a base layer (second base portion) 220, a diaphragm layer (second diaphragm portion) 230, and a cover layer 240 are layered in this order.

[0059] The base layer (second base portion) 220 of the second microvalve 200A is formed with a branch port 263A branching from the flow path on the inlet side of the first microvalve 200, and an outlet port 264A for discharging the gas introduced from the branch port 263A to the outside of the mass spectrometer 30. The outlet port 264A is connected to the flow path 32 that communicates between the mass spectrometer 30 and the rotary pump 31.

[0060] The diaphragm layer (second diaphragm portion) 230 of the second microvalve 200A elastically deforms under the pressure of the pneumatic fluid supplied from the flow controller 50 via the solenoid valve 42, thereby switching between communication and blocking between the branch port 263A and the exhaust port 264A.

[0061] When the control device 100 closes the solenoid valve 42, no pneumatic fluid is supplied to the second microvalve 200A. In this case, the second microvalve 200A is in an open state (exhaust state) in which the branch port 263A and the exhaust port 264A communicate with each other.

[0062] When the control device 100 opens the solenoid valve 42, pneumatic fluid is supplied to the second microvalve 200A. In this case, the second microvalve 200A is in a closed state (non-exhaust state) that blocks the branch port 263A and the exhaust port 264A.

[0063] The switching device 40A functions as a diverter that switches whether the gas from the column 20 is supplied to the mass spectrometer 30 or exhausted to the outside by controlling the open / closed state of the first microvalve 200 and the second microvalve 200A.

[0064] When replacing the column 20 using the switching device 40A (diverter) according to the first modified example, the procedure for replacing the column 20 can be set as follows.

[0065] When the control device 100 receives a signal instructing the start of column 20 replacement in response to the user pressing the "Start column replacement" button, the control device 100 closes the first microvalve 200 (shutoff state). This seals the vacuum system of the mass spectrometer 30, making it possible to replace the column 20. At this time, the second microvalve 200A may be in either an open state (exhaust state) or a closed state (non-exhaust state).

[0066] Thereafter, when the control device 100 receives a signal indicating that the column 20 replacement is complete in response to the user pressing the "Column Replacement Complete" button after replacing the column 20, the control device 100 resumes the supply of carrier gas, maintains the first microvalve 200 in a closed state (blocking state), and opens the second microvalve 200A in an open state (exhaust state). This allows gas or residual components in the replaced column 20 to be discharged to the outside without being supplied to the mass spectrometer 30. After the replaced column 20 is sufficiently purged with carrier gas, the control device 100 closes the second microvalve 200A in a non-exhaust state and opens the first microvalve 200 in an open state (communicating state). This allows the column 20 and the mass spectrometer 30 to communicate with each other, enabling analysis. This prevents air or residual components in the replaced column 20 from entering the mass spectrometer 30, thereby avoiding a decrease in the vacuum level of the mass spectrometer 30 and contamination of the ion source.

[0067] As described above, when replacing the column 20 using the switching device 40A (diverter) according to this modified example 1, it is possible to avoid a decrease in the degree of vacuum of the mass spectrometer 30 and contamination of the ion source due to air or residual components in the replaced column 20 being mixed into the mass spectrometer 30.

[0068] Furthermore, the outlet 264A of the first microvalve 200 is connected to a flow path 32 that connects the mass spectrometer 30 and the rotary pump 31. This allows the rotary pump 31 to be used to suck in the exhaust gas from the switching device 40A (diverter).

[0069] [Variation 2] In the above-described variation 1, the switching device 40A (diverter) is used to evacuate air or remaining components from the replaced column 20. However, the use of the above-described switching device 40A (diverter) is not limited to evacuating air or remaining components from the replaced column 20, and it may also be used to evacuate impurities in the sample gas during analysis.

[0070] In general, among gas chromatographic detectors, those using a radioactive source such as an electron capture detector (ECD) or a sulfur chemiluminescence detector (SCD) using a combustion tube are known to be susceptible to contamination and require complex maintenance. In particular, since an ECD has a radioactive source, it cannot be easily disassembled and cleaned.

[0071] Furthermore, in MS (mass spectrometers), ion source contamination can significantly affect analytical results by causing sensitivity fluctuations, making ion source maintenance complicated. MS is used for simultaneous multi-component analysis of pesticide residues in food and the environment due to its high qualitative capabilities, but in recent years, the trend toward simplified sample pretreatment has led to an increase in the number of cases where insufficient cleanup, or so-called dirty samples, is analyzed, making ion source maintenance more complicated.

[0072] When a dirty sample containing many impurities is analyzed using a gas detection device such as the ECD, SCD, or MS, the gas detection device becomes contaminated, which increases the frequency of maintenance and leads to increased running costs.

[0073] Therefore, by switching the flow path using switching device 40A (diverter) composed of two inert microvalves with extremely small dead volume as described above, impurity components (unnecessary components other than the target component) in the sample gas are not introduced into the gas detection device during operation (analysis) of the gas detection device, but are discharged to the outside of the gas detection device. This allows only the target component for analysis to be introduced into the gas detection device, preventing contamination of the gas detection device by impurities.

[0074] FIG. 6 shows an example of using the switching device 40A (diverter) described above to discharge unnecessary components to the outside of the mass spectrometer 30 during analysis. The sample gas that has passed through the column 20 contains both the target component to be analyzed and impurity components other than the target component. Therefore, the control device 100 closes the first microvalve 200 (blocking state) and opens the second microvalve 200A (exhaust state) during times other than when the target component is introduced from the column 20 to discharge the impurity components separated in the column 20 to the outside. Also, during times when the target component is introduced from the column 20, the control device 100 closes the second microvalve 200A (non-exhaust state) and opens the first microvalve 200 (communicating state). This allows the switching device 40A (diverter) to be operated so that only the target component is introduced into the ion source of the mass spectrometer 30 and the impurity components are exhausted to the outside of the mass spectrometer 30. As a result, only the target component is introduced into the ion source of the mass spectrometer 30, and no impurity components are introduced, thereby preventing contamination of the ion source.

[0075] As described above, by switching the flow path of the switching device 40A (diverter) during analysis, two flow paths (a flow path for introducing gas into the mass spectrometer 30 and a flow path for exhausting gas) are alternately switched during analysis. In this case, if the resistances of the two flow paths differ significantly, switching the flow paths may cause fluctuations in the pressure on the outlet side of the column 20. Because the retention time of the column 20 varies depending on the differential pressure between the inlet and outlet pressures of the column 20, there is a concern that switching the flow paths may cause fluctuations in the retention time of the column 20. Therefore, if the fluctuations in the retention time of the column 20 are large, it is possible to suppress fluctuations in the retention time of the column 20 by supplying makeup gas to the switching device 40A (diverter) and controlling the carrier gas linear velocity of the column 20 using differential pressure.

[0076] 7 is a diagram schematically illustrating an example of the configuration of an analysis module 2B according to Modification 2. The analysis module 2B uses the ECD 30 as a gas detection device and includes a pressure adjustment mechanism 50B that supplies makeup gas to a switching device 40A (diverter) to differentially control the linear velocity of the carrier gas in the column 20. The pressure adjustment mechanism 50B supplies makeup gas to both the exhaust flow path of the first microvalve 200 and the exhaust flow path of the second microvalve 200A.

[0077] 8 is a diagram schematically illustrating an example of the configuration of another analysis module 2C according to Modification 2. The analysis module 2C uses the ECD 30 as a gas detection device and includes a pressure adjustment mechanism 50C that supplies makeup gas to a switching device 40A (diverter) to differentially control the linear velocity of the carrier gas in the column 20. The pressure adjustment mechanism 50C supplies makeup gas to a portion of the flow path on the inlet side of the first microvalve 200 before branching to the second microvalve 200A.

[0078] As described above, even if the resistances of the two flow paths switched by the switching device 40A (diverter) are significantly different, it is possible to suppress fluctuations in the retention time of the column 20 by supplying makeup gas to the switching device 40A (diverter) and controlling the carrier gas linear velocity of the column 20 by differential pressure control.

[0079] [Aspects] It will be understood by those skilled in the art that the above-described embodiments and their modifications are specific examples of the following aspects.

[0080] (Item 1) A gas chromatograph mass spectrometry system according to one aspect includes a column that separates components contained in a sample gas, a mass spectrometer that analyzes the sample gas by ionizing the gas that passes through the column under vacuum conditions, and a switching device having a first microvalve located at the connection between the column and the mass spectrometer. The first microvalve includes a first base portion having an inlet for introducing gas from the column into the interior and an outlet for allowing the gas introduced from the inlet to flow out to the mass spectrometer, and a first diaphragm portion located opposite the first base portion and elastically deforming to switch between communication between the inlet and the outlet.

[0081] According to the gas chromatograph mass spectrometry system described in paragraph 1, a switching device having a first microvalve with a minimal dead volume is disposed at the connection between the column and the mass spectrometer. This allows the user to replace the column with the simple operation of switching the state of the first microvalve. Furthermore, even when the supply of carrier gas is resumed after column replacement, the minimal dead volume of the first microvalve minimizes the amount of gas other than the carrier gas supplied to the mass spectrometer. As a result, the user can replace the column with a simple operation without reducing the degree of vacuum in the mass spectrometer.

[0082] (Item 2) In the gas chromatograph mass spectrometry system according to item 1, the first microvalve is formed of single crystal silicon.

[0083] In the gas chromatograph mass spectrometry system described in paragraph 2, the first microvalve is formed of inert single-crystal silicon, so that even if high-temperature gas is supplied to the mass spectrometer through the first microvalve, high-precision analysis can be performed in the mass spectrometer.

[0084] (Item 3) The gas chromatograph mass spectrometry system described in item 1 further includes a control device that controls the state of the first diaphragm. When the control device receives a signal indicating that column replacement should begin, the control device sets the first microvalve to a blocking state that blocks the inlet and outlet, and when the control device receives a signal indicating that column replacement is complete, the control device sets the first microvalve to a communicating state that connects the inlet and outlet.

[0085] According to the gas chromatograph mass spectrometry system described in paragraph 3, the state of the first microvalve is controlled by the control device, so that a user can seal the vacuum system of the mass spectrometer and replace the column by simply inputting a control command to the control device.

[0086] (4) In the gas chromatograph mass spectrometry system described in 1, the switching device includes a second microvalve in addition to the first microvalve. The second microvalve includes a second base portion formed with a branch port branching from the inlet flow path of the first microvalve and an outlet port for discharging gas introduced from the branch port to the outside of the mass spectrometer, and a second diaphragm portion disposed opposite the second base portion and elastically deforming to switch between communication between the branch port and the outlet port.

[0087] According to the gas chromatograph mass spectrometry system described in paragraph 4, the switching device can function as a diverter to switch between a flow path that introduces gas from the column into the mass spectrometer and a flow path that exhausts gas from the column to the outside without introducing it into the mass spectrometer.

[0088] (Item 5) The gas chromatograph mass spectrometry system described in Item 4 further includes a control device that controls the state of the first diaphragm portion and the state of the second microvalve. When the control device receives a signal indicating the start of column replacement, it switches the first microvalve to a blocking state that blocks the inlet and outlet. When the control device receives a signal indicating the completion of column replacement, it switches the second microvalve to an exhaust state that connects the branch port and outlet while maintaining the first microvalve in the blocking state, thereby discharging gas from the replaced column to the outside. After the gas from the replaced column has been discharged to the outside, it switches the second microvalve to a non-exhaust state that blocks the branch port and outlet, and switches the first microvalve to a communicating state that connects the inlet and outlet.

[0089] According to the gas chromatograph mass spectrometry system described in paragraph 5, after replacing the column, the switching device switches the flow path to vent gas or residual components in the replaced column to the outside while the vacuum system of the mass spectrometer is sealed, and the column can be connected to the mass spectrometer after the inside of the replaced column has been sufficiently replaced with carrier gas. This prevents a decrease in the vacuum level of the mass spectrometer and contamination of the ion source due to air or residual components in the replaced column being mixed into the mass spectrometer.

[0090] (Item 6) A gas detection system according to one aspect includes a column for separating components contained in a sample gas, a detection device for detecting the gas separated by the column, and a diverter having a first microvalve and a second microvalve disposed at a connection between the column and the detection device. The first microvalve includes a first base portion formed with an inlet for introducing gas from the column into the first microvalve and an outlet for allowing the gas introduced from the inlet to flow out to the detection device, and a first diaphragm portion disposed opposite the first base portion and elastically deformable to switch between communication between the inlet and the outlet. The second microvalve includes a second base portion formed with a branch port branching from an inlet-side flow path of the first microvalve and an outlet port for discharging the gas introduced from the branch port to the outside of the detection device, and a second diaphragm portion disposed opposite the second base portion and elastically deformable to switch between communication between the branch port and the outlet.

[0091] According to the gas detection system described in paragraph 6, a diverter having a dead volume including a first microvalve and a second microvalve is disposed at the connection between the column and the detector. By using the diverter to switch the flow path, unnecessary components in the sample gas are discharged outside the detector during operation (analysis) of the detector, preventing them from entering the detector. This allows only the target components for analysis to be introduced into the detector, preventing contamination of the detector by impurities.

[0092] (Item 7) The gas detection system described in Item 6 further includes a control device that controls the state of the first diaphragm portion and the state of the second microvalve. The control device sets the first microvalve to a blocking state that blocks the inlet and the outlet while setting the second microvalve to an exhaust state that connects the branch port and the outlet so as to exhaust the gas introduced from the column during a time period other than when the target component is introduced from the column, and sets the second microvalve to a non-exhaust state that blocks the branch port and the outlet while setting the first microvalve to a communicating state that connects the inlet and the outlet during a time period when the target component is introduced from the column.

[0093] According to the gas detection system described in paragraph 7, the flow path switching by the diverter is controlled by the control device. Therefore, a user can perform flow path switching by the diverter with the simple operation of inputting a control command to the control device.

[0094] (Item 8) In the gas detection system described in Item 6, the detection device is a mass spectrometer that analyzes gases separated in the column by ionizing the gases under vacuum conditions. The gas detection system further includes a rotary pump for reducing the pressure inside the mass spectrometer. The outlet of the second microvalve is connected to a flow path that communicates between the mass spectrometer and the rotary pump.

[0095] According to the gas detection system described in paragraph 8, the exhaust gas from the diverter can be sucked in by utilizing a rotary pump for reducing the pressure inside the mass spectrometer.

[0096] (Item 9) The gas detection system according to item 6 further includes a pressure adjustment mechanism that adjusts the pressure difference between the inlet and outlet of the column by supplying make-up gas to the diverter.

[0097] According to the gas detection system described in paragraph 9, even if the resistances of the flow paths switched by the diverter differ greatly, the linear velocity of the carrier gas in the column can be controlled by supplying makeup gas to the diverter. Therefore, even if the resistances of the flow paths switched by the diverter differ greatly, fluctuations in the retention time of the column can be suppressed.

[0098] (Item 10) A gas chromatograph mass spectrometry system according to one aspect includes a column for separating components contained in a sample gas, a mass spectrometer for analyzing the sample gas by ionizing the gas that has passed through the column under vacuum conditions, and a switching device having a first microvalve disposed at a connection between the column and the mass spectrometer. The first microvalve is made of single crystal silicon.

[0099] According to the gas chromatograph mass spectrometry system described in paragraph 10, a switching device having a first microvalve made of inert single-crystal silicon is disposed at the connection between the column and the mass spectrometer, so that even if high-temperature gas is supplied to the mass spectrometer through the first microvalve, high-precision analysis can be performed in the mass spectrometer.

[0100] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0101] 1 Gas chromatograph mass spectrometry system, 2, 2A, 2B, 2C Analysis module, 50 Flow controller, 10 Injection port, 20 Column, 30 Mass spectrometer, 31 Rotary pump, 32 Flow path, 40, 40A Switching device, 41, 42 Solenoid valve, 50B, 50C Pressure adjustment mechanism, 60 Input device, 70 Display device, 100 Control device, 110 Calculation unit, 120 Memory unit, 200 First microvalve, 200A Second microvalve, 220 Base layer, 221, 241 Recess, 222, 223, 224, 232, 252, 253, 254 Opening, 225 Bottom, 230 Diaphragm layer, 233 Flexible portion, 234 Rigid portion, 240 Cover layer, 250 Flow path member, 262 Supply port, 263 Inflow port, 263A Branch port, 264 Outflow port, 264A Discharge port.

Claims

1. A gas chromatograph mass spectrometry system comprising: a column for separating components contained in a sample gas; a mass spectrometer for analyzing the sample gas by ionizing the gas that has passed through the column in a vacuum state; and a switching device having a first microvalve arranged at the connection between the column and the mass spectrometer, wherein the first microvalve comprises: a first base portion formed with an inlet for introducing gas from the column into the interior and an outlet for discharging the gas introduced from the inlet to the mass spectrometer; and a first diaphragm portion arranged opposite the first base portion and elastically deforming to switch between communication and blocking between the inlet and the outlet.

2. The gas chromatography mass spectrometry system of claim 1, wherein the first microvalve is formed of single crystal silicon.

3. A gas chromatograph mass spectrometry system as described in claim 1, further comprising a control device that controls the state of the first diaphragm portion, wherein the control device changes the state of the first microvalve to a blocking state that blocks the inlet and the outlet when it receives a signal to start replacing the column, and changes the state of the first microvalve to a communicating state that connects the inlet and the outlet when it receives a signal to indicate that replacement of the column is complete.

4. The gas chromatograph mass spectrometry system of claim 1, wherein the switching device comprises a second microvalve in addition to the first microvalve, and the second microvalve comprises: a second base portion formed with a branch port branching off from the inlet side flow path of the first microvalve and an outlet port for discharging gas introduced from the branch port to the outside of the mass spectrometer; and a second diaphragm portion disposed opposite the second base portion and elastically deforming to switch between communication and blocking between the branch port and the outlet port.

5. A gas chromatograph mass spectrometry system as described in claim 4, further comprising a control device that controls the state of the first diaphragm portion and the state of the second microvalve, wherein the control device, when receiving a signal to start replacing the column, changes the state of the first microvalve to a blocking state that blocks the inlet and the outlet, and when receiving a signal to indicate that replacement of the column is complete, changes the state of the second microvalve to an exhaust state that connects the branch port and the outlet while maintaining the state of the first microvalve to the blocking state, thereby discharging gas within the replaced column to the outside, and after the gas within the replaced column has been discharged to the outside, changes the state of the second microvalve to a non-exhaust state that blocks the branch port and the outlet, and changes the state of the first microvalve to a communicating state that connects the inlet and the outlet.

6. A gas detection system comprising: a column for separating components contained in a sample gas; a detection device for detecting gas separated by the column; and a diverter having a first microvalve and a second microvalve, arranged at the connection between the column and the detection device, wherein the first microvalve comprises: a first base portion formed with an inlet for introducing gas from the column into the interior and an outlet for discharging the gas introduced from the inlet to the detection device; and a first diaphragm portion arranged opposite the first base portion and elastically deforming to switch between connecting and blocking the inlet and the outlet; and the second microvalve comprises: a second base portion formed with a branch port branching from the inlet side flow path of the first microvalve and an outlet port for discharging the gas introduced from the branch port to the outside of the detection device; and a second diaphragm portion arranged opposite the second base portion and elastically deforming to switch between connecting and blocking the branch port and the outlet.

7. A gas detection system as described in claim 6, further comprising a control device that controls the state of the first diaphragm portion and the state of the second microvalve, wherein the control device, during a time period other than a time period when the target component is introduced from the column, sets the first microvalve to a blocking state that blocks the inlet and the outlet, while setting the second microvalve to an exhaust state that connects the branch port and the outlet, thereby discharging the gas introduced from the column to the outside, and during a time period when the target component is introduced from the column, sets the second microvalve to a non-exhaust state that blocks the branch port and the outlet, while setting the first microvalve to a communicating state that connects the inlet and the outlet.

8. The gas detection system of claim 6, wherein the detection device is a mass spectrometer that analyzes the gas separated in the column by ionizing the gas under vacuum conditions, and further comprises a rotary pump for reducing the pressure inside the mass spectrometer, and the outlet of the second microvalve is connected to a flow path that communicates between the mass spectrometer and the rotary pump.

9. The gas detection system according to claim 6, further comprising a pressure adjusting mechanism that adjusts the pressure within the column by supplying makeup gas to the diverter.

10. A gas chromatograph mass spectrometry system comprising: a column for separating components contained in a sample gas; a mass spectrometer for analyzing the sample gas by ionizing the gas that has passed through the column under vacuum conditions; and a switching device having a first microvalve located at the connection between the column and the mass spectrometer, wherein the first microvalve is made of single crystal silicon.

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