Gas analyzers

Abstract

A gas analyzer capable of repeatedly measuring and analyzing trace amounts of gas contained in a gas to be measured with high sensitivity, stability, and good reproducibility. [Solution] A gas analyzer comprising: a mass manifold that holds an ion source and quadrupole section of a quadrupole mass spectrometer; a nozzle provided within the mass manifold with an outlet positioned near the ion source; a gas injection pipe that communicates with the outlet of the nozzle and supplies a gas to be analyzed toward the ion source through the outlet; and an exhaust pipe that communicates with the outlet of the nozzle and is configured to exhaust the gas in a direction different from the direction of ejection of the gas to be measured.

Description

[Technical Field]

[0001] The present invention relates to a gas analyzer. [Background technology]

[0002] In the past, to analyze gas components derived from specimens or in the environment, it was necessary to introduce the sample gas into a vacuum chamber in which the ion source of the mass spectrometer was placed. -3 ~10 -5 Pa) and atmospheric pressure (approx. 10 5 Because an extremely large pressure difference occurs between the ion source and the gas source (Pa), gas is supplied to the ion source of the mass spectrometer while evacuating using a multi-stage vacuum pumping system or a large-capacity vacuum pumping system.

[0003] As an example of the gas analyzer, Patent Document 1 discloses a gas analyzer that includes a measured gas reservoir, a small container with a small on-off valve, a buffer tank, a manifold, a vacuum container equipped with a quadrupole mass spectrometer, an orifice and piping leading to the ion source of the quadrupole mass spectrometer, and a vacuum exhaust device consisting of two systems of a turbomolecular pump and a diaphragm pump that evacuate the manifold and the vacuum container equipped with the quadrupole mass spectrometer. It is described that this gas analyzer can improve the repeatability of measurements by utilizing the buffer tank, manifold, etc. to repeatedly reproduce the pulse shape of the measured gas flow.

[0004] Furthermore, Patent Document 2 discloses a gas analyzer that is composed of one or more gas reservoirs, a gas inlet, a pre-tank, a buffer tank, a vacuum vessel in which an ion generation unit of a mass spectrometer is disposed, one vacuum exhaust system, a variable leak valve, piping, and a gas inlet with a septum structure made of natural rubber, etc. This gas analyzer is described as being capable of determining whether the components of gases to be measured are the same. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-53003 [Patent Document 2] Patent Publication No. 2021-18100 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the gas analyzer described in Patent Document 1 controls the gas injection amount using a variable leak valve installed at the outlet of the gas reservoir tank, making fine adjustment of the gas flow rate difficult and making stable and reproducible measurements difficult. Furthermore, excessive opening of the variable leak valve increases the pressure inside the manifold, resulting in unstable flow control using an orifice with a fixed diameter. Furthermore, the relatively large space created by components such as on-off valves and welded joints makes it difficult to ensure the specified volume, resulting in a complex and large-scale overall device configuration. Regarding exhaust, the exhaust time constant is short (approximately 10 seconds), which can lead to the target gas being exhausted before it reaches the ion source within the measurement time, potentially making it difficult to analyze high-molecular-weight components.

[0007] Furthermore, the gas analyzer of Patent Document 2 uses absorbent materials such as natural rubber and silicone rubber in the gas inlet. These materials not only emit odorous components, but also tend to cause problems such as reduced airtightness due to needle insertion and the inclusion of atmospheric gases. Furthermore, the pre-tank to buffer tank ratio is extremely large, resulting in a very large overall device volume, making it unsuitable for rapid or repeated measurements. Furthermore, a single-system vacuum pumping configuration using only a turbomolecular pump makes it difficult to ensure sufficient pumping performance and maintain a stable high vacuum. In particular, when multiple gas reservoirs are used, the influence of residual gas history in the reservoir supply and inlet sections and incomplete pumping can make accurate comparative evaluation of gas components difficult.

[0008] Furthermore, in the case of a configuration in which an orifice is used to inject the measurement gas, as in the gas analyzers of Patent Documents 1 and 2, the differential pressure is likely to cause reflected flow or dead flow areas within the system, and it takes time to expel the residual gas, which leaves issues with the efficiency and accuracy of repeated measurements.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a gas analyzer that can repeatedly measure and analyze trace amounts of gas contained in a gas to be measured with high sensitivity, stability, and good reproducibility. [Means for solving the problem]

[0010] In order to achieve the above object, the gas analyzer of the present invention comprises: a mass manifold for holding an ion source and a quadrupole part of the quadrupole mass spectrometer; a nozzle provided in the mass manifold and having an ejection opening located near the ion source; a gas injection pipe that is in communication with the ejection opening of the nozzle and that supplies the gas to be analyzed toward the ion source through the ejection opening; an exhaust pipe that is connected to the ejection opening of the nozzle and configured to exhaust the gas in a direction different from the ejection direction of the gas to be measured; It has the following characteristics. [Effects of the Invention]

[0011] According to one embodiment of the present invention, it is possible to provide a gas analyzer that can repeatedly measure and analyze trace amounts of gas contained in a gas to be measured with high sensitivity, stability, and good reproducibility. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing the overall configuration of an example of a gas analyzer according to this embodiment. [Figure 2] FIG. 2 shows an example of exhaust characteristics indicating a change in pressure inside the mass manifold after gas injection in the gas analyzer according to this embodiment. [Figure 3]FIG. 3 is a schematic diagram illustrating a gas injection mechanism into the mass manifold in the gas analyzer according to this embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating an example of the arrangement of gas injection piping and injected gas exhaust piping in the gas analyzer according to this embodiment. [Figure 5] FIG. 5 is a schematic diagram illustrating another example of the arrangement of the gas injection pipe and the injected gas exhaust pipe in the gas analyzer according to this embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the internal configuration of the mass manifold in the gas analyzer according to this embodiment. [Figure 7] FIG. 7 is a schematic diagram of an example of a syringe set as a sampling means and filling means for a gas to be measured. [Figure 8] FIG. 8 is a schematic diagram of the gas introduction section 220 in the gas analyzer according to this embodiment. [Figure 9] FIG. 9 is a schematic diagram showing another example of the configuration of the gas introduction section 220 in the gas analyzer according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] A gas analyzer according to an embodiment of the present invention will be described below with reference to the drawings.

[0014] (Overall composition) A gas analyzer according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 shows a schematic overall configuration diagram of the gas analyzer according to this embodiment.

[0015] 1, the gas analyzer 100 according to this embodiment is mainly composed of five systems: a gas injection system 200, a gas analysis system 300, an injection gas exhaust system 400, an analysis gas exhaust system 500, and preferably a heating system 600. Each system will be described in detail below.

[0016] Gas injection system 200 constitutes a flow path for introducing the gas to be measured into gas analysis system 300, and from the upstream side, at least a gas inlet section 220, a gas inlet pipe 202, a gas manifold 204 connected to gas inlet pipe 202, and a gas injection pipe 206 connected to gas manifold 204 are provided, and the gas to be measured is supplied to gas analysis system 300 via gas injection pipe 206. An example configuration of gas inlet section 220 will be described later.

[0017] The gas inlet pipe 202 forms a flow path that guides the measurement target gas introduced from a gas inlet section 220 (described later) to the gas manifold 204, and is usually provided with an inlet valve 208. The gas injection pipe 206 forms a flow path that guides the measurement target gas introduced into the gas manifold 204 to the gas analysis system 300, and is usually provided with a first on-off control valve 210.

[0018] The gas introduction pipe 202 is connected to a nozzle 320 according to this embodiment. The detailed structure of the nozzle 320 will be described later with reference to FIGS.

[0019] The gas manifold 204 not only collects and distributes the gas flow paths, but also serves to mitigate sudden inflow and outflow of the gas to be measured, thereby suppressing fluctuations in the flow rate to the gas analysis system 300 .

[0020] The gas analysis system 300 serves to analyze the components of the injected gas, and is configured to include at least a mass manifold 302 and a quadrupole mass spectrometer 304 .

[0021] The mass manifold 302 serves to control the pressure and stabilize the flow rate of the flow path that guides the measurement target gas injected from the gas injection system 200 to the ion source 306 of the quadrupole mass spectrometer 304, and is connected to the injected gas exhaust system 400.

[0022] The quadrupole mass spectrometer 304 typically has an ion source 306, a quadrupole section 308, and a detector 310, and the data detected by the detector 310 is output as a mass spectrum by a control device 312, and is configured to perform component analysis.

[0023] In this embodiment, at least the ion source 306 and the quadrupole section 308 are held in a mass manifold 302. A pressure gauge 314 is connected to the mass manifold 302, and is configured to be able to measure the pressure inside the mass manifold 302.

[0024] The injected gas exhaust system 400 serves to suppress the occurrence of dead-flow areas in the flow path through which the target gas is injected into the gas analysis system 300, and includes at least an exhaust device 402 and injected gas exhaust piping 404 connecting the exhaust device 402 to the mass manifold 302. The injected gas exhaust system 400 also preferably includes exhaust piping 406 connecting the exhaust device 402 to the gas manifold 204.

[0025] The injected gas exhaust pipe 404 is connected to the nozzle 320 according to this embodiment, similar to the gas injection pipe 206. The detailed structure of the nozzle 320 will be described later with reference to FIGS.

[0026] The injected gas exhaust pipe 404 and the exhaust pipe 406 are provided with a second on-off control valve 408 and a third on-off control valve 410, respectively.

[0027] The analysis gas exhaust system 500 serves to exhaust gas from the gas analysis system 300 and includes an exhaust device 502. The exhaust device 402 and the exhaust device 502 are the same as those used for the measurement by the quadrupole mass spectrometer 304. -5 ~10 -7 Since the analysis is carried out in a high vacuum environment of about 100 Pa, there are no particular limitations as long as this degree of vacuum can be achieved, but in consideration of the weight of the entire gas analyzer and the influence of minute vibrations generated during pump operation, it is preferable to use a turbo molecular pump and an auxiliary pump (e.g., a diaphragm pump), etc. It is also preferable to provide a silencer or the like in exhaust devices 402 and 502 in order to reduce the influence of exhaust noise and exhaust gases.

[0028] FIG. 2 shows an example of the exhaust characteristics showing the pressure change inside the mass manifold after gas injection in the gas analyzer according to this embodiment, with the vertical axis representing the pressure inside the mass manifold and the horizontal axis representing the time after gas injection. For example, when the exhaust time constant is adjusted to about 40 seconds, gas (about 0.2 mL) at atmospheric pressure is pumped to a high vacuum state (about 10 -5 When a pressure of 10 Pa is injected into the mass manifold, the pressure inside the mass manifold temporarily increases to 10 -2 The pressure rises to about 10 Pa. The gas is then gradually exhausted by a vacuum pumping device with an effective pumping speed of approximately 70 L / sec, gradually reducing the pressure. In this case, in order to accurately measure components in the mass number range of 1 to 200 using a quadrupole mass spectrometer, if the exhaust time constant is too small, the measured components will be exhausted, potentially affecting measurement accuracy. Therefore, by appropriately setting the exhaust time constant, it is possible to reliably capture and analyze the target molecular weight components.

[0029] Although not shown in Figure 2, once the gas has been completely evacuated, the pressure inside the mass manifold drops to the measurement background level. The ultimate pressure when all on-off control valves are at their maximum openings is a higher vacuum state than the measurement background, ensuring a more sufficient vacuum. If evacuation is continued for a sufficient amount of time, the pressure will approach the ultimate background level, maintaining a highly reproducible measurement environment.

[0030] In the gas analyzer 100 according to this embodiment, the temperature control by the heating system 600 serves to suppress the effects of gas adsorption and desorption, improve the stability and reproducibility of peaks, improve detection sensitivity, prevent contamination inside the apparatus, and the like, and is performed by a heating means (not shown).

[0031] As the heating means, a mantle heater, sheath heater, ribbon heater, or the like is selected and used depending on the application, and it is preferable to adopt a heat insulating structure in which these are covered with a heat insulating material such as glass wool.

[0032] As shown by the dashed dotted line in FIG. 1 , it is preferable to control the temperatures of the gas inlet pipe 202, the gas manifold 204, the gas injection pipe 206, the mass manifold 302, the valves 208, 210, 408, 410, the injected gas exhaust pipe 404, and the exhaust pipe 406 by the heating system 600.

[0033] Although it depends on the type of gas being measured and the measurement conditions, the above heating range is usually set to 100°C or higher, but within this heating range, the surface of the insulation material can be kept below 60°C, making it possible to achieve safe and stable temperature control.

[0034] Furthermore, because gas components are easily affected by temperature changes, it is extremely important to monitor and control the temperature within the system. However, temperature differences tend to occur between the temperature of the insulation material and the actual materials (each valve, manifold, etc.), and when a thermocouple is fixed to the surface of the measurement target component with tape, there is a problem that accurate temperature measurement is difficult because temperature variations occur due to tape peeling, thermocouple misalignment, and gaps with the target component.

[0035] Therefore, in this embodiment, it is preferable that each valve has a structure in which a thermocouple is placed and fixed between fixing plates made of a material that is the same as or has a similar thermal conductivity to the valve material, and that the manifold has a structure in which a groove is provided on the outer surface of the manifold, in which the thermocouple is housed, and further fixed using the same material as the fixing plates. Furthermore, it is preferable that each pipe has a thermocouple tightly fixed using a belt or the like made of a material that is the same as or has a similar thermal conductivity to the pipe, and that these are covered with a heat-insulating material (insulating material) such as aluminum foil or glass wool. This structure can significantly improve the accuracy of temperature measurement and temperature control.

[0036] The shapes of the gas manifold 204 and the mass manifold 302 are not particularly limited as long as they can hold the ion source 306 and the quadrupole section 308 within the mass manifold 302 .

[0037] The capacity of the gas manifold 204 and the mass manifold 302 is preferably in the range of 1:1,000-1,500:10,000-15,000 as the volume ratio between the volume of the micro gas reservoir of the gas introduction section 220 (described later), the volume of the gas manifold 204, and the volume of the mass manifold 302. By setting the volume ratio within the above range, it is possible to achieve both a reduction in the overall size of the gas analyzer 100 and the functions of each manifold described above.

[0038] (Example of a configuration of an injection gas exhaust system using a nozzle) Next, a detailed configuration example of the injected gas exhaust pipe 404 using the nozzle 320 according to this embodiment will be described in more detail with reference to the drawings.

[0039] Figure 3 shows a schematic diagram illustrating the gas injection mechanism into the mass manifold in the gas analyzer according to this embodiment, with Figure 3(a) showing the gas injection mechanism using a conventional orifice structure and Figure 3(b) showing the gas injection mechanism using the nozzle structure according to this embodiment. Note that in Figure 3, for the sake of explanation, the gas injection direction and exhaust direction are indicated generally by arrows.

[0040] As shown in FIG. 3(a), conventionally, gas injection pipe 206 is fixed to mass manifold 302 by flange 316 attached to opening 302a of mass manifold 302. Then, the gas to be measured is injected as a contracted flow into mass manifold 302 through hole 318a (diameter: approximately 0.3 mm) of orifice member 318 attached to the end of gas injection pipe 206. During this process, turbulent flow, reflected flow, and dead flow areas are formed in the vicinity of hole 318a, creating a structure in which residual gas associated with these factors tends to accumulate within mass manifold 302. This residual gas is exhausted to the mass manifold 302 side through orifice hole 318a and also through gas injection pipe 206, but exhaust takes a long time due to conductance limitations.

[0041] On the other hand, as shown in FIG. 3(b), the gas injection mechanism according to this embodiment includes a nozzle 320 disposed within mass manifold 302, with an outlet 320a positioned to eject the target gas as a contracted flow. Gas injection piping 206 is configured to communicate with outlet 320a of nozzle 320, and injected gas exhaust piping 404 is configured to communicate with outlet 320a and exhaust the target gas in a direction different from the ejection direction of the target gas. In this configuration, the target gas supplied from gas injection piping 206 passes through nozzle 320 and is ejected from outlet 320a into mass manifold 302. Residual gas associated with a dead flow area or reflected flow formed within nozzle 320 is effectively exhausted via injected gas exhaust piping 404, resulting in a structure in which residual gas is less likely to accumulate.

[0042] The opening diameter of ejection opening 320a of nozzle 320 is preferably within a range of 0.3 mm to 2.0 mm, and particularly preferably about 1.0 mm. By setting the opening diameter of ejection opening 320a within the above range, the measurement target gas can be ejected as a contracted flow, and residual gas can be exhausted in a short time.

[0043] In the gas analyzer of this embodiment, by adopting the above-mentioned nozzle structure, it is possible to quickly exhaust reflected gas and residual gas remaining in the dead flow area, thereby reducing changes in the composition of the gas to be measured and adverse effects on measurement accuracy, and improving the responsiveness and reliability of the entire gas analyzer.

[0044] (Other configuration examples of gas injection piping and injected gas exhaust piping) 4 is a schematic diagram illustrating an example of the arrangement of gas injection piping and injected gas exhaust piping in the gas analyzer according to this embodiment. As described above, the measurement target gas supplied from gas injection piping 206 passes through nozzle 320 and is ejected from ejection opening 320a into mass manifold 302. Residual gas associated with dead flow areas and reflected flows formed within nozzle 320 is effectively exhausted via injected gas exhaust piping 404, resulting in a structure in which residual gas is less likely to accumulate.

[0045] The angle between the direction of connection of nozzle 320 to gas injection pipe 206 and the direction of connection of nozzle 320 to injection gas exhaust pipe 404 can be set appropriately within the range of 0 to 90 degrees (see gas injection pipe 206 and injection gas exhaust pipes 404a-404c in FIG. 4 ). However, considering the design of the pipe connections, the installation positions of the valves, and the shape and dimensions of flange 316, it is preferable to set the angle within the range of 20 to 40 degrees (see gas injection pipe 206 and injection gas exhaust pipe 404a). Setting the angle to an acute angle of, for example, approximately 20 to 40 degrees not only shortens the overall length of the pipe but also minimizes the conductance (gas flow) in the pipe, thereby achieving high sealing performance, excellent exhaust efficiency, and compactness of the device. This improves responsiveness in the series of operations from gas introduction to analysis and exhaust, and increases the reliability of measurement accuracy.

[0046] The position of the injected gas exhaust pipe 404 is not particularly limited as long as the exhaust direction through the injected gas exhaust pipe 404 is different from the direction in which the gas to be measured is ejected. As shown in FIG. 4, the pipe may be configured to be located below the gas injection pipe 206, or above the gas injection pipe 206, and the pipe can be flexibly positioned depending on the other components.

[0047] 5A and 5B are schematic diagrams illustrating examples of the arrangement of gas injection piping and injection gas exhaust piping in the gas analyzer according to this embodiment. More specifically, FIG. 5A shows an example of an arrangement in which the angle formed by the connection direction of nozzle 320 with gas injection piping 206 and the connection direction of nozzle 320 with injection gas exhaust piping 404 is an acute angle. FIG. 5B shows an example of an arrangement in which the angle formed by the connection direction of nozzle 320 with gas injection piping 206 and the connection direction of nozzle 320 with injection gas exhaust piping 404 is an acute angle. 5(c) is an example of an arrangement where the angle between the connection direction of the nozzle 320 to the gas injection pipe 206 and the connection direction of the nozzle 320 to the injection gas exhaust pipe 404 is 90 degrees (however, the angle between the injection direction of the injection gas near the ejection opening in the nozzle and the exhaust direction is 90 degrees, as in FIG. 5(b)).

[0048] The exhaust structure using the nozzle 320 according to this embodiment can suppress the residual of the measurement target gas and enable quick recovery to a vacuum, but the exhaust performance varies depending on the nozzle shape.

[0049] 5(a), in which the injection gas exhaust pipe 404 and the gas injection pipe 206 are connected at an acute angle, the conductance of the exhaust path is suppressed and the flow rate of the exhaust gas is easily maintained, resulting in high exhaust efficiency and suppressing gas retention in the nozzle 320. As a result, repeated measurements can be performed in a short time, and highly sensitive analysis of trace gas components (ppb level) is realized.

[0050] 5(b) and 5(c), in order to exhaust the injected gas exhaust pipe 404 using the exhaust device 402, the flow path of the injected gas exhaust pipe 404 needs to be bent at a right angle or the like along the way, which may increase the exhaust conductance and reduce the local flow rate compared to the structure shown in Fig. 5(a). Therefore, although the exhaust performance is slightly inferior to the structure shown in Fig. 5(a), it increases the design freedom of the entire gas analyzer 100 and may be an advantageous configuration in terms of space efficiency.

[0051] In the exhaust system of this embodiment, the exhaust speed has little pressure dependency, so differences in the exhaust structure do not result in extremely long exhaust times. Furthermore, the gas flow rate that passes through the nozzle 320 and reaches the mass manifold 302 reaches the ion source 306 in proportion to the pressure within the mass manifold 302, where it is ionized and a specific analyte element (mass-to-charge ratio (m / z)) is detected.

[0052] (Example of arrangement inside a mass manifold) FIG. 6 is a schematic diagram of the mass manifold in the gas analyzer according to this embodiment. As shown in FIG. 6, in order to accurately and efficiently introduce the target gas to be measured in a contracted flow state ejected from the nozzle 320 into the ion source 306, it is preferable to ionize the gas before it diffuses as it is ejected from the ejection opening 320a of the nozzle 320. Therefore, in this embodiment, the distance between the ejection opening 320a of the nozzle 320 and the ion source 306 is preferably set within a range of 1.0 mm to 4.0 mm, and more preferably approximately 2.0 mm. Considering the material characteristics (e.g., thermal expansion coefficient) of each component in a heated environment and the micro-vibrations (especially those caused by pump operation) that affect the entire gas analyzer, it is preferable to set the distance within the above range in order to prevent interference between components and to achieve both stability and sensitivity of the gas analysis.

[0053] Furthermore, the nozzles 320 are detachably attached via flanges 316 provided on the outside of the mass manifold 302, and are configured so that nozzle 320 arrangements of different dimensions and shapes and flange 316 sizes can be selected according to the external dimensions and specifications of the mass manifold 302. This allows for flexible application to different analytical devices and also improves maintainability and replacement workability.

[0054] (Gas inlet) Next, an example of a means for introducing gas into the gas analyzer according to this embodiment will be described with reference to the drawings.

[0055] 7 shows a schematic diagram of an example of a syringe set used as a sampling means and filling means for a gas to be measured. As shown in FIG. 7(a), syringe set 700 is integrally configured with an injection needle 702, a three-way stopcock 704, a syringe 706, and a plunger 708. The injection needle 702 is inserted into a sample bag or other gas supply source, and the plunger 708 in syringe 706 is pulled to aspirate the gas to be measured. At this time, by leaving the three-way stopcock 704 in an open state, the gas to be measured is smoothly introduced into syringe 706.

[0056] 7(b) shows the state of the syringe set after it has been filled with the gas to be measured, and after filling, the gas to be measured can be sealed in the syringe 706 and easily transported by removing the injection needle 702 with the three-way stopcock 704 closed. Furthermore, if the injection needle 702 is not used, the gas to be measured can be similarly sealed in by pulling the plunger 708 while keeping the three-way stopcock 704 open to aspirate the gas to be measured, and after the desired amount of gas to be measured has been filled into the syringe 706, closing the three-way stopcock 704.

[0057] Next, a method for introducing the measurement target gas held in syringe set 700 as described above into gas injection system 200 of gas analyzer 100 will be described with reference to the drawings.

[0058] FIG. 8 shows a schematic diagram of the gas introduction section 220 in the gas analyzer according to this embodiment. FIG. 8( a) shows an example in which a gas reservoir 710 prefilled with a gas to be measured, a first three-way stopcock 712, a second three-way stopcock 714, and a stopcock joint 716 are provided from the upstream side and connected to the gas introduction pipe 202. In this configuration, gas in the gas reservoir 710 is supplied to the downstream introduction system via the first three-way stopcock 712 and the second three-way stopcock 714. The gas reservoir 710 is configured as a bag- or container-like structure and can hold a relatively large amount of gas. It is also possible to introduce a certain amount of gas into the gas analyzer 100 in multiple batches. The space formed between the first three-way stopcock 712 and the second three-way stopcock 714 can also function as a gas reservoir. The space formed between the first three-way stopcock 712 and the second three-way stopcock 714 is preferably in the range of 0.1 mL to 0.3 mL, and particularly preferably about 0.2 mL.

[0059] FIG. 8(b) shows a configuration in which the sample gas is introduced into the gas inlet pipe 202 using the syringe set 700 shown in FIG. 7 . The syringe set 700, a second three-way stopcock 714, and a stopcock joint 716 are provided upstream and connected to the gas inlet pipe 202. In this case, the three-way stopcock 704 of the syringe set 700 serves the same function as the first three-way stopcock 712. In this embodiment, the space formed between the three-way stopcock 704 of the syringe set 700 and the second three-way stopcock 714 functions as a gas reservoir with a minute volume of approximately 0.2 mL. This configuration is preferable from the viewpoints of simplifying pipe connection even when the sample gas is in a minute amount, reducing operational errors during operation, and suppressing the risk of gas adsorption and retention.

[0060] FIG. 8(c) shows another configuration for introducing a gas to be measured into the gas inlet pipe 202 using the syringe set 700 shown in FIG. 7 described above. This example shows an example in which, from upstream, the syringe set 700, a first three-way stopcock 712, a second three-way stopcock 714, and a stopcock joint 716 are provided and connected to the gas inlet pipe 202. In this embodiment, the space formed between the three-way stopcock 704 of the syringe set 700 and the first three-way stopcock 712, and the space formed between the first three-way stopcock 712 and the second three-way stopcock 714 function as a gas reservoir with a minute volume of approximately 0.2 mL. This configuration is preferable from the viewpoints of simplifying pipe connection even when the amount of gas to be measured is small, reducing operational errors during operation, and suppressing the risk of gas adsorption and retention.

[0061] As described above, with the above configuration, the space between the three-way stopcocks forms a gas reservoir with a very small volume. This allows for strict control of the amount of sample gas introduced, resulting in highly accurate analysis results. Furthermore, the gas introduction section 220 can be formed with a simple structure using a syringe set, which provides excellent on-site operability, easy repeated use, and a reproducible measurement environment.

[0062] The gas analyzer according to this embodiment may employ a configuration that utilizes a multiple three-way stopcock as the gas inlet in order to rapidly and continuously measure multiple target gases. Fig. 9 shows a schematic configuration diagram of another example of the gas inlet 220 in the gas analyzer according to this embodiment.

[0063] Figure 9(a) shows a multiple three-way stopcock in which three three-way stopcocks 718, 720, and 722 are connected in series, and Figure 9(b) shows an example in which syringe sets 700a, 700b, 700c, and 700d are connected to each of the three-way stopcocks. Figure 9(c) shows an example in which a three-way stopcock 724 is further connected downstream of the multiple three-way stopcock, and Figure 9(d) shows an example in which a second three-way stopcock 714 is connected downstream of this three-way stopcock 724. Figure 9(e) shows an example in which a first three-way stopcock 712 and a second three-way stopcock 714 are connected downstream of the three-way stopcock 724.

[0064] By arranging the three-way stopcocks in a hierarchical manner in this way, the options for gas introduction paths are expanded without modifying the gas analyzer itself, and continuous measurement of a greater number of gas species becomes possible.

[0065] In a configuration using such a multiple three-way stopcock, multiple measurement gases can be introduced into a single gas reservoir path by sequentially opening and closing the three-way stopcocks of each syringe, allowing for continuous measurement. This configuration is particularly suitable for supplying trace gases in multiple pulses, and allows for precise control of continuous gas injection and ionization. The three-way stopcocks of each syringe can be opened and closed manually or automatically, and the system can be expanded into an automatic continuous measurement device using automatic switching control.

[0066] (Gas analysis method) As an example of a gas analysis method using the gas analyzer according to this embodiment, a case where analysis is performed by the gas analyzer shown in FIG. 1 using the gas introduction unit 220 shown in FIG. 8(b) will be described. When gas analysis is performed using the gas analyzer according to this embodiment, the inside of the mass manifold is first brought into a high vacuum state (for example, 10 -5The apparatus is assumed to be started with the pressure reaching a pressure of 100 Pa or less, the heating system of the apparatus components being controlled to a heated state (for example, 100 to 200°C), and the exhaust time constant, the opening of the first on-off control valve 210, and the opening of the second on-off control valve 408 being adjusted to predetermined values. Furthermore, as a matter of course, the quadrupole mass spectrometer is started up in advance, and the ion source, quadrupole unit, and detector are in a state where measurements can be made.

[0067] First, syringe set 700 filled with the gas to be measured (three-way stopcock 704 is in the "closed" state) is prepared and connected to second three-way stopcock 714, which is also in the "closed" state. This forms a gas reservoir with a minute capacity (for example, about 0.2 mL) in the space between three-way stopcock 704 and second three-way stopcock 714.

[0068] During the connection work, atmospheric air and other gases are usually mixed in, so it is necessary to exhaust the mixed gas. Therefore, by opening the second three-way stopcock 714 and opening the third on-off control valve 410, the mixed atmospheric air is exhausted by the exhaust device 402. After a predetermined vacuum pressure is reached, the second three-way stopcock 714 is closed.

[0069] Next, three-way stopcock 704 is opened, and the gas reservoir is filled with the gas to be measured. After filling, three-way stopcock 704 is closed. To perform the co-washing process using the filled gas, second three-way stopcock 714 is opened to temporarily evacuate the gas, and then closed again. Three-way stopcock 704 is opened again, and the gas reservoir is filled with the gas to be measured, completing preparation of the gas to be measured.

[0070] Thereafter, in order to inject the gas to be measured into the gas analysis system, the third on-off control valve 410 is set to the "closed" state and the second three-way stopcock 714 is switched to the "open" state, whereby the gas to be measured is supplied to the ion source 306 of the quadrupole mass spectrometer 304 via the gas manifold 204, the first on-off control valve 210, and the nozzle 320. In the ion source 306, the gas components are ionized by an electron beam, and the analyte elements (mass-to-charge ratio (m / z)) are separated and detected by the quadrupole, and the ions are acquired as a spectrum.

[0071] After the measurement is completed, the third on-off control valve 410 is opened again and the second three-way stopcock 714 is closed to evacuate the remaining gas and reduce the pressure in the mass manifold to the measurement background level. This operation allows for a quick transition to the next measurement cycle.

[0072] The gas analyzer according to this embodiment uses two (or more) three-way stopcocks as gas inlets, allowing for the formation of a small gas reservoir in the space between the stopcocks, enabling highly accurate and reproducible gas introduction and analysis. Furthermore, by facilitating co-washing and repeated introduction of gases, the effects of released gases and adsorbable components are minimized, significantly contributing to stabilization of the background pressure within the mass manifold 302. Furthermore, the gas analyzer according to this embodiment can easily repeat pulsed gas supply, enabling highly sensitive analysis of trace components, making it extremely useful in sample analysis, which requires repeatable reproducibility and stability.

[0073] As described above, the gas analyzer according to this embodiment includes an injection pipe having a nozzle that ejects the target gas as a contracted flow into the mass manifold 302, and an exhaust pipe connected to the injection pipe near the nozzle's outlet and configured to exhaust the target gas in a direction different from the direction of ejection. This nozzle structure effectively exhausts residual gas associated with dead flow areas and reflected flows formed in the flow path through the injection gas exhaust pipe, preventing stagnation of the residual gas. Furthermore, by selecting the exhaust direction and angle, the exhaust design can be flexibly tailored to the application, enabling, for example, a compact device or high-sensitivity analysis.

[0074] Furthermore, the gas analyzer according to this embodiment can use a small-capacity gas reservoir using a three-way stopcock as the gas inlet. Therefore, it is possible to strictly control the amount of sample gas introduced without using a buffer tank or small container, and highly accurate analysis results can be obtained. Furthermore, a simple structure using a syringe set allows sample gas to be introduced in pulses or continuously, which provides excellent on-site operability, easy repetitive use, and a reproducible measurement environment.

[0075] Furthermore, in the gas analyzer according to this embodiment, the gas inlet pipe, gas manifold, gas injection pipe, mass manifold, valves, injected gas exhaust pipe, and exhaust pipe are all temperature-controlled by heating means, which allows for stable gas supply, rapid exhaust, and improved measurement reproducibility, making it possible to repeatedly measure trace gases derived from specimens and trace components in the atmosphere in a short period of time.

[0076] The gas analyzer according to this embodiment is configured as a small, portable, or vehicle-mounted type, and can be used both indoors and outdoors. When used indoors, it is necessary to ensure that the exhaust gas from the vacuum exhaust system does not affect the measurement target. In this case, it is preferable to connect an auxiliary exhaust diaphragm pump and exhaust gas discharge pipe to the exhaust ports of the diaphragm pumps on the gas manifold and mass manifold sides to suppress indoor diffusion of the exhaust gas and ensure stable exhaust performance.

[0077] Furthermore, to improve the portability and durability of the gas analyzer, it is preferable to use bellows that can absorb thermal expansion and contraction, expansion joints for absorbing vibrations, and flexible piping made of fluororesin for the piping, and to fix the turbomolecular pump and diaphragm pump with vibration absorbers to reduce the effects of thermal deformation and micro-vibrations on the measurement. Furthermore, the entire gas analyzer can be easily moved using a stand with casters, etc.

[0078] As described above, the gas analyzer according to this embodiment is configured as a small, portable, vehicle-mounted type, and its main power consumption is comprised of the exhaust system, measurement and analysis equipment, and heating means. The gas analyzer according to this embodiment is configured to limit overall power consumption to less than 100V AC / 10A (1,000W or less), so that it can be operated in field environments where general commercial power is not always available. This allows the device to operate stably using power supplied from solar panels, portable power sources, small generators, etc., in addition to commercial power sources, making it possible to measure and analyze gases outdoors or in emergencies.

[0079] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configurations should not be considered to be limited to these embodiments. The scope of the present invention is defined not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0080] 100 Gas analyzer 200 Gas injection system 202 Gas introduction piping 204 Gas manifold 206 Gas injection piping 208 Inlet valve 210 First on-off control valve 220 Gas inlet 300 Gas Analysis System 302 Mass Manifold 302a opening 304 Quadrupole mass spectrometer 306 Ion Source 308 Quadrupole 310 Detector 312 Control device 314 Pressure Gauge 316 flange 318 Orifice member 318a Hole 320 nozzle 320a spout opening 400 Injection gas exhaust system 402 Exhaust system 404 Injection gas exhaust piping 406 Exhaust piping 408 Second on-off control valve 410 Third on-off control valve 500 Analysis gas exhaust system 502 Exhaust system 600 Heating system 700 Syringe Set 702 Syringe needle 704 Three-way stopcock 706 Syringe 708 Pusher 710 Gas Reservoir 712 First three-way stopcock 714 Second three-way stopcock 716 Stopcock joint 718 Three-way stopcock 720 Three-way stopcock 722 Three-way stopcock 724 Three-way stopcock

Claims

1. a mass manifold for holding an ion source and a quadrupole part of the quadrupole mass spectrometer; a nozzle provided in the mass manifold so that an ejection opening for ejecting the target gas in a contracting flow is positioned near the ion source; a gas injection pipe that is in communication with the ejection opening of the nozzle and that supplies the gas to be analyzed toward the ion source through the ejection opening; an injection gas exhaust pipe that is connected to the ejection opening of the nozzle and configured to exhaust the gas in a direction different from the ejection direction of the target gas; A gas analyzer having:

2. 2. The gas analyzer according to claim 1, wherein the inner diameter of the ejection opening of the nozzle is within a range of 0.3 mm to 2.0 mm.

3. an angle formed between a direction in which the nozzle is connected to the gas injection pipe and a direction in which the nozzle is connected to the injection gas exhaust pipe is within a range of 20 degrees or more and 40 degrees or less; 2. The gas analyzer of claim 1.

4. a distance between the ejection opening of the nozzle and the ion source is within a range of 1.0 mm to 4.0 mm; 2. The gas analyzer of claim 1.

5. the gas injection pipe is connected to a gas inlet via a gas manifold; the gas introduction section includes a first three-way stopcock, a second three-way stopcock connected to the first three-way stopcock, a stopcock joint connected to the second three-way stopcock, and a gas introduction pipe connecting the stopcock joint and the gas manifold; 2. The gas analyzer of claim 1.

6. The volume of the space formed between the first three-way stopcock and the second three-way stopcock is in the range of 0.1 mL to 0.3 mL.

6. The gas analyzer of claim 5.

7. The gas to be analyzed is pre-filled in a syringe, The syringe is connected to the first three-way stopcock, thereby introducing the gas to be analyzed into the system of the gas analyzer.

6. The gas analyzer of claim 5.

8. The gas to be analyzed is filled in a gas reservoir in advance, The gas reservoir is connected to the first three-way stopcock, thereby introducing the target gas into the system of the gas analyzer.

6. The gas analyzer of claim 5.

9. a volume ratio between a space formed between the first three-way stopcock and the second three-way stopcock, and a volume ratio between the gas manifold and the mass manifold is within a range of 1:1,000 to 1,500:10,000 to 15,000; 7. The gas analyzer of claim 6.

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