JPH0668842A - Mass spectrometry device - Google Patents

Abstract

PURPOSE:To provide a mass spectrometry device in which an ion source can readily be attached to/detached from an analyzer tube. CONSTITUTION:A gas introducing tube 11 is installed on an analyzer tube 1 separately from an ion source 2. In addition, as a means to achieve connection/ disconnection of a gas introducing port 10 of an ionizing chamber 5 to/from a forward end of the gas introducing tube 11 simultaneously as the ion source 2 is attached to/detached from the analyzer tube 1, a ball-shaped tubular coupling 28 is installed on the forward end of the gas introducing tube 11, and a coil spring 29 to apply the tubular coupling 28 to an edge of the gas introducing port 10 of the ionizing chamber 5 is installed. In this constitution, the ion source 2 can be attached to/detached from the analyzer tube 1 easily without connecting/disconnecting the gas introducing tube 11 to/from a gas tube 14 of a sample gas introducing system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to analyze the components of a sample gas by introducing the sample gas into an ionization chamber of an ion source detachably attached to an analysis tube and ionizing it, and separating the ions according to their masses. And a mass spectrometer for analyzing a gas sample.

[0002]

2. Description of the Related Art FIG. 5 is a schematic structural view showing a conventional example of this type of mass spectrometer, and shows only an ion source part in a sectional view.

As shown in the figure, this mass spectrometer comprises an ion source 2 at one end of an analytical tube 1 made of metal, an ion separator 3 at the middle part, and an ion detector 4 at the other end.

The ion source 2 comprises an ionization chamber 5,
The sample gas is ionized in the ionization chamber 5,
In the case of this conventional example, the metal is formed into a rectangular parallelepiped shape, and is ionized by the most general electron impact method. And this ion source 2
Are removably mounted in the analysis tube 1 by a hermetically sealing flange. That is, the ion source flange 6 is removably attached to the open end of the analysis tube 1 while being positioned by the pin 7, and the inner surface of the ion source flange 6 is
The ion source 2 is supported by a support rod 9 via an insulator 8.

The ionization chamber 5 of the ion source 2 is provided with a gas introduction port 10 opening toward the ion source flange 6, and the gas introduction port 1 is made of metal.
1 are connected via an insulating tube 12. The gas introduction pipe 11 is provided in a state of penetrating the ion source flange 6, and a gas introduction flange 13 formed at the end of the gas introduction pipe 11 is provided with a gas pipe of a sample gas introduction system provided outside the analysis pipe 1. 14 are connected.

Further, the ion source 2 has a hot filament 15 for emitting electrons and an electron trap 16 for receiving the emitted electrons, as shown in FIG. Are provided so as to face each other in the thickness direction of the analysis tube 1 through a pair of electron passage holes 17 provided in the ionization chamber 5, and the ionization chamber 5 faces the ion separation unit 3. Thus, an ion emission slit 18 having a long opening in the electron flight direction is formed. Further, a lens electrode 19 for accelerating ions and a ground electrode 20 are connected in parallel to each other on the side of the ion separation unit 3 of the ion source 2, and the electrodes 19 and 20 are connected to the ions of the ionization chamber 5 by ion beams. Ion passage slits 21 and 22 are formed corresponding to the emission slits 18.

In addition, a plurality of lead electrodes 23 (only one is shown) connecting the hot filament 15 and the lens electrode 19 to an external power source penetrate through the ion source flange 6 through an insulating member 24. It is provided in the state. A gas leak 25 for controlling the amount of sample gas introduced is attached to the opening of the gas introduction flange 13 as required.

In the ion source 2 having the above structure, the analysis tube 1
The sample gas in the ionization chamber 5 is introduced into the ionization chamber 5 through the gas pipe 14 and the gas introduction pipe 11 in a state where the inside pressure is low, and the sample gas in the ionization chamber 5 is discharged from the hot filament 15 toward the electron trap 16. The sample gas is ionized by colliding the electrons and giving a shock. Then, by applying an accelerating voltage between the ionization chamber 5 and the ground electrode 20, the ions in the ionization chamber 5 are led out from the ion emission slit 18 as an ion beam, and the ion passage slits 21 and 22 of the electrodes 19 and 20.
And is ejected toward the ion separation unit 3. At that time, the lens electrode 19 focuses the ion beam and adjusts its direction. Thus, the ions generated in the ionization chamber 5 are sent to the ion separation unit 3 as a band-shaped ion beam.

The ion separator 3 separates the ions from the ion source 2 according to the mass, and may be of a magnetic field type or a quadrupole type. In the magnetic field type, the ions from the ion source 2 are separated according to their masses by utilizing the difference in the trajectories in the magnetic field. In the quadrupole type, the ions from the ion source 2 are separated according to the mass by sieving with a high-frequency electric field formed by the quadrupole. The ions separated by the ion separator 3 are sent to the ion detector 4.

The ion detector 4 includes a secondary electron multiplier, a DC amplifier, etc. (not shown), and detects the ions separated by the ion separator 3. And this ion detector 4
It is possible to measure the relative intensity with respect to the numerical value of the mass / charge of ions, that is, a so-called mass spectrum, from the detection result of 1, and analyze the components of the sample gas based on the mass spectrum.

By the way, the ionization chamber 5 of the ion source 2
The inside of the is inevitably contaminated by the sample gas. If the next sample gas is analyzed while the ionization chamber 5 is contaminated, the sample gas reacts with the contaminants and an accurate analysis result cannot be obtained. Therefore, the ion source 2 is removed from the analysis tube 1 and the ionization chamber 5 is removed. It is necessary to clean the inside. In some cases, the ion source 2 may be replaced depending on the type of sample gas. Further, in the case where the ion source 2 is provided with the hot filament 15, the hot filament 15
Even when the gas is cut, the ion source 2 needs to be removed from the analysis tube 1 and replaced. From these things, the ion source 2
Are removably attached to the analysis tube 1 as described above.

[0012]

However, in the above conventional mass spectrometer, the ion source 2 and the gas introduction pipe 11 are integrally attached to the analysis pipe 1 by using the ion source flange 6, so that When the source 2 is removed from the analysis tube 1, the gas introduction tube 11 must be disconnected from the sample gas introduction system, and when the removed ion source 2 is reattached to the analysis tube 1, the gas introduction tube 11 Must be reconnected to the sample gas introduction system. That is, there is a problem that it takes much time and effort to attach and detach the ion source 2 to and from the analysis tube 1.

The present invention has been made to solve this problem, and an object thereof is to provide a mass spectrometer in which the ion source can be easily attached to and detached from the analysis tube.

[0014]

In order to achieve the above object, in a mass spectrometer according to the present invention, a gas introduction tube is provided separately from an ion source in a state in which a tip of the gas introduction tube is projected into the analysis tube. By attaching and detaching the ion source to and from the analysis tube, a means for simultaneously connecting and disconnecting the gas introduction port of the ionization chamber of the ion source and the tip of the gas introduction tube was provided.

[0015]

According to the above construction, when the ion source is attached to the analysis tube, the tip of the gas introduction tube attached to the analysis tube separately from the ion source is simultaneously connected to the gas introduction port of the ionization chamber of the ion source. To be done. When the ion source is removed from the analysis tube, the tip of the gas introduction tube is simultaneously separated from the gas introduction port of the ionization chamber. Therefore, when attaching or detaching the ion source to or from the analysis tube, it is not necessary to connect or disconnect the gas introduction tube and the sample gas introduction system.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

Among the constituent elements in the embodiment, the same constituent elements as those in the conventional example shown in FIGS. 5 and 6 are designated by the same reference numerals and the description thereof will be omitted.

Embodiment 1 FIG. 1 is a cross-sectional view of essential parts showing an ion source of a mass spectrometer according to Embodiment 1 of the present invention.

As shown in the figure, in this mass spectrometer, an ion source 2 for ionizing a sample gas by an electron impact method is supported by a hermetically sealed ion source flange 6 with a support rod 9 via an insulator 8. The gas introduction port 10 that is detachably attached inside the open end of the analysis tube 1 and that is provided in the ionization chamber 5 of the ion source 2 has a gas introduction port 10 in a direction perpendicular to the length direction of the ion emission slit 18. It opens toward the tube wall of No. 1. Moreover, the edge of the gas inlet 10 of the ion source 2 is formed in a concave shape so that a spherical tubular joint described later can be fitted thereto.

The gas introduction pipe 11 for introducing the sample gas into the ionization chamber 5 of the ion source 2 is provided on the tube wall of the analysis tube 1 separately from the ion source 2, and the tip thereof is the gas introduction port of the ionization chamber 5. It is attached in a state of protruding toward the inside of the analysis tube 1 toward 10. That is, the introduction tube mounting opening 26 protruding outward is formed on the tube wall of the analysis tube 1, and the gas introduction flange 13 at the end of the gas introduction tube 11 is positioned by the pin 27 at the tip of the installation opening 26. It is installed in a closed state. The analysis tube 1 is attached to the gas introduction flange 13.
Gas pipe 14 of the sample gas introduction system provided outside the
Are connected.

Further, the tip of the gas introduction pipe 11 protruding into the analysis tube 1 is connected to the tip of the gas introduction pipe 11 and the gas introduction port 10 of the ionization chamber 5. Through hole 2
The tubular joint 28 having 8a is slidably attached with the tip of the gas introducing pipe 11 inserted into the through hole 28a, and the tubular joint 28 is fitted with the gas introducing port 10a.
A coil spring 29, which is an elastic member to be pressed into contact with, is wound. One end of this coil spring 29 has a gas introduction pipe 11
The other end is attached to the tubular joint 28, respectively.

The shape of the tubular joint 28 is rounded, for example, spherical so that the tubular joint 28 can be advanced and retracted by coming into contact with the detachable ion source 2 as described later. The tubular joint 28 is made of a metal ion source 2
And the gas introduction tube 11 are electrically insulated from each other, and a heat-resistant insulation such as quartz glass is used so that the hot filament (see FIG. 6) that emits electrons does not deform even if it comes into contact with the ion source 2 that becomes hot. Material is used.

In the mass spectrometer of the above construction, when the ion source 2 is inserted into the analysis tube 1 along the direction of the central axis of the analysis tube 1, the spherical tubular joint 28 at the tip of the gas introduction tube 11 becomes It abuts the lower edge of the source 2 and retracts.
When the ion source 2 is attached to the analysis tube 1 at a fixed position, the tubular joint 28 is pressed by the elastic force of the coil spring 29 so as to be fitted to the concave edge of the gas introduction port 10 of the ionization chamber 5. To do. As a result, the gas introduction port 10 of the ionization chamber 5 and the tip of the gas introduction pipe 11 are reliably connected. When the ion source 2 is removed by pulling it out from the analysis tube 1 contrary to the time of attachment, the tubular joint 28 at the tip of the gas introduction tube 11 is once retracted to form a concave shape of the gas introduction port 10 of the ionization chamber 5. The gas introduction port 10 of the ionization chamber 5 and the tip of the gas introduction pipe 11 are separated from each other.

That is, in this mass spectrometer, the ion source 2
The gas inlet 10 of the ionization chamber 5 of the ion source 2 and the gas inlet pipe 11
The connection and disconnection with the tip of can be achieved at the same time. Thereby, the ion source 2 can be easily attached to and detached from the analysis tube 1 without connecting or disconnecting the gas introduction tube 11 to or from the sample gas introduction system.

It should be noted that a certain amount of sample gas is used in the analysis tube 1.
Since there is no problem even if it leaks into the interior, the connection structure of the gas introduction pipe 11 and the gas introduction port 10 using the tubular joint 28 is
It is not necessary to have a completely airtight structure. Further, the other configuration of the mass spectrometer and the mass spectrometric operation are the same as those of the conventional example, and therefore the description thereof is omitted here.

Example 2 As in Example 1 above, the ion source 2 was attached to the analysis tube 1,
When attaching and detaching in the direction of the central axis of the analytical tube 1, as shown in the cross-sectional view of the main part of FIG.
0 and the tip of the gas introduction pipe 11 may be opposed to each other in the central axis direction of the analysis pipe 1.

That is, in the mass spectrometer according to the second embodiment, the gas introduction port 10 of the ionization chamber 5 is opened toward the insertion direction of the ion source 2 into the analysis tube 1 and protrudes into the analysis tube 1. The tip of the gas introducing pipe 11 is bent at a right angle toward the gas introducing port 10. A tubular joint 28 and a coil spring 29 are attached to the tip of the gas introducing pipe 11 as in the first embodiment.
However, in the case of the second embodiment, the shape of the tubular joint 28 does not have to be spherical, and may be a cylindrical shape with a tapered tip. Further, the edge of the gas introduction port 10 is formed in a concave shape so that the tip of the cylindrical tubular joint 28 fits therein.

In the above structure, the ion source 2 is connected to the analysis tube 1
When the tubular joint 28 is mounted so as to be inserted into the ionization chamber 5, the tubular joint 28 is pressed against the edge of the gas introduction port 10 of the ionization chamber 5 by the elastic force of the coil spring 29, whereby the tips of the gas introduction port 10 and the gas introduction pipe 11 of the ionization chamber 5 are inserted. And are securely connected. When the ion source 2 is removed by pulling it out of the analysis tube 1, the tubular joint 28 is separated from the gas introduction port 10 of the ionization chamber 5, and the gas introduction port 10 and the gas introduction pipe 11 are removed.
Is separated from the tip of.

Therefore, also in the case of the second embodiment, by attaching and detaching the ion source 2 to and from the analysis tube 1, the gas inlet 10 of the ionization chamber 5 of the ion source 2 and the gas inlet tube 1 will be described.
The connection and disconnection with the tip of No. 1 can be achieved at the same time, and the same effect as that of the first embodiment can be obtained.

Embodiment 3 FIG. 3 is a cross-sectional view of essential parts showing an ion source of a mass spectrometer according to Embodiment 3 of the present invention.

As shown in the figure, the difference between this mass spectrometer and the first embodiment is that the ion source 2 is attached to the analysis tube 1 so as to be attached and detached in the direction of the gas introduction tube 11.
That is, in this mass spectrometer, the ion source mounting opening 3 is formed on the tube wall of the analysis tube 1 on the side opposite to the introduction tube mounting opening 26.
0 is formed, and the ion source flange 6 is detachably attached to the tip of the ion source attachment opening 30 while facing the gas introduction flange 13 and positioned by the pin 7. And on the inner surface of the ion source flange 6,
The ion source 2 is supported by a support rod 9 via an insulator 8.

The connection structure between the ion source 2 and the gas introduction pipe 11 in this mass spectrometer is the same as in the first and second embodiments, and when the ion source 2 is attached to the analysis pipe 1, the gas introduction pipe 11 is installed. The tubular joint 28 slidably attached to the tip of the ion spring is pressed against the gas introduction port 10 of the ionization chamber 5 of the ion source 2 by the elastic force of the coil spring 29, whereby the gas introduction port 10 of the ionization chamber 5 and the gas introduction pipe. 1
The tip of 1 is surely connected. Further, when the ion source 2 is removed from the analysis tube 1, the tubular joint 28 is moved to the ionization chamber 5
The gas introduction port 10 is separated from the gas introduction port 10 and the tip of the gas introduction pipe 11 is separated.

Therefore, also in the case of the third embodiment, by attaching and detaching the ion source 2 to and from the analysis tube 1, the gas introduction port 10 of the ionization chamber 5 of the ion source 2 and the gas introduction tube 1 are removed.
The connection and disconnection with the tip of No. 1 can be achieved at the same time, and the same effect as that of the first embodiment can be obtained.

In the case of the third embodiment, since the ion source 2 is attached and detached in the direction of the gas introduction pipe 11,
The shape of the tubular joint 28 does not have to be spherical, and may be cylindrical as in the second embodiment.

Embodiment 4 FIG. 4 is a cross-sectional view of essential parts showing an ion source of a mass spectrometer according to Embodiment 4 of the present invention.

As shown in the figure, the difference from the first embodiment of this mass spectrometer is that the ionization chamber 5 of the ion source 2 is provided with a gas outlet 31 separately from the gas inlet 10.
A gas discharge pipe 32 for discharging the sample gas in the ionization chamber 5 from the gas discharge port 31 to the outside of the analysis pipe 1 is provided separately from the ion source 2 with the tip of the gas discharge pipe 32 protruding into the analysis pipe 1. It is a point attached to 1.

The gas outlet 31 of the ionization chamber 5 is formed symmetrically with the gas inlet 10 with the ionization chamber 5 at the center, and the gas outlet pipe 32 is connected to the gas inlet pipe 11 with the ion source 2 in between. Installed symmetrically.

That is, in this mass spectrometer, a discharge pipe attachment opening 33 is formed on the tube wall of the analysis pipe 1 on the opposite side of the introduction pipe attachment opening 26, and the tip of the discharge pipe attachment opening 33 is Gas exhaust flange 34 at the end of the gas exhaust pipe 32
, Are removably attached while being positioned by the pin 35. And on the gas discharge flange 34,
A gas pipe 36 of a sample gas discharge system provided outside the analysis pipe 1 is connected.

Further, at the tip of the gas discharge pipe 32,
Similar to the gas introduction pipe 11, a through hole 37a that connects the tip of the gas discharge pipe 32 and the gas discharge port 31 of the ionization chamber 5 to each other.
A spherical tubular joint 37 having the above is slidably attached, and a coil spring 38 which is an elastic member for pressing the tubular joint 37 to the gas discharge port 31 is wound.

In the mass spectrometer having the above structure, since the gas outlet 31 and the gas outlet pipe 32 are provided, when the active gas or the adsorptive gas is analyzed, those gases are promptly exhausted by the sample gas exhaust system. Thus, it is possible to prevent contamination in the ionization chamber 5. Moreover, the gas discharge pipe 32 is attached to the analysis pipe 1 separately from the ion source 2 like the gas introduction pipe 11, and the tubular joint 37 and the coil spring 38 are attached to the tip thereof, so that the ion source 2 is analyzed. By attaching / detaching the tube 1 in the direction of the central axis of the analysis tube 1, the gas inlet 10 of the ionization chamber 5 and the tip of the gas introduction tube 11 are simultaneously connected and separated, and the gas in the ionization chamber 5 is separated. Connection and disconnection between the discharge port 31 and the tip of the gas discharge pipe 32 can be achieved at the same time. This gas inlet 10 and gas inlet pipe 1
1, the gas exhaust port 31 and the gas exhaust pipe 3
The connection and separation operation with the tip of the gas introduction port 2 is the same as the connection and separation operation with the tip of the gas introduction port 10 and the gas introduction pipe 11 in the first embodiment.

Therefore, the ion source 2 can be easily connected to the analysis tube 1 without connecting and disconnecting the gas introducing tube 11 and the sample gas introducing system and connecting and disconnecting the gas exhaust tube 32 and the sample gas exhausting system. It can be attached and detached.

In each of the first to fourth embodiments, the gas introduction pipe 11 or the gas discharge pipe 32 is replaced with the gas introduction flange 1
Although it is attached to the tube wall of the analysis tube 1 via the gas discharge flange 3 or the gas discharge flange 34, it may be attached in a state of directly penetrating the tube wall of the analysis tube 1.

Further, in each of the above Examples 1 to 4, the tip of the tubular joint 28 or 37 is formed in a convex shape, and the edge of the gas inlet 10 or the gas outlet 31 with which they are in pressure contact is formed in a concave shape. Conversely, tubular joint 28 or 37
The gas inlet 10 or the gas outlet 3 with a concave tip
The edge of 1 may be formed in a convex shape.

Furthermore, in each of the above-mentioned first to fourth embodiments, the ion source 2 of the type in which the sample gas is ionized by the electron impact method has been described as an example, but the structure according to the present invention has the gas introduction port 10 of the ionization chamber 5. Alternatively, the ion source 2 in which the gas inlet pipe 11 or the gas outlet pipe 32 is connected to the gas outlet 31 can be applied to an ion source of a type that ionizes a sample gas by a chemical ionization method or an electric field ionization method. .

[0045]

As described above, according to the mass spectrometer of the present invention, the ion source can be easily attached to and detached from the analysis tube without connecting or disconnecting the gas introduction tube and the sample gas introduction system. can do.

Further, in the mass spectrometer according to the present invention in which the gas introduction pipe and the gas discharge pipe are connected to the ionization chamber of the ion source, the gas introduction pipe and the sample gas introduction system are connected and disconnected, and the gas discharge pipe and the sample are connected. The ion source can be easily attached to and detached from the analysis tube without connecting or disconnecting with the gas exhaust system.

Therefore, the cleaning of the ionization chamber, the replacement of the ion source, and the replacement of the hot filament are
It can be done easily and quickly.

[Brief description of drawings]

FIG. 1 is a sectional view of essential parts showing an ion source of a mass spectrometer according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing an ion source of a mass spectrometer according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an essential part showing an ion source of a mass spectrometer according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of essential parts showing an ion source of a mass spectrometer according to a fourth embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a conventional example, in which only an ion source portion is shown in a sectional view.

6 is a view taken along the line AA of FIG.

[Explanation of symbols]

 1 Analytical Tube 2 Ion Source 3 Ion Separation Section 4 Ion Detection Section 5 Ionization Chamber 10 Gas Inlet Port 11 Gas Introducing Tube 14 Gas Tube (Sample Gas Introducing System) 28 Tubular Joint 29 Coil Spring 36 Gas Tube (Sample Gas Exhaust System) 37 Tubular Joint 38 Coil spring

Claims (4)

[Claims] 1. An ion source for ionizing a sample gas in an ionization chamber is detachably attached to one end of the analysis tube by a hermetically sealing flange in the analysis tube, and a gas introduction port provided in the ionization chamber of the ion source, A gas introduction tube connected to a sample gas introduction system outside the analysis tube is connected, and an ion separation section for separating ions from the ion source according to mass is provided in the middle section of the analysis tube. In a mass spectrometer for gas sample analysis, which comprises an ion detector for detecting the ions separated by the ion separator at the other end of the tube, the gas introduction tube is provided with its tip protruding into the analysis tube. In this state, it is attached to the analysis tube separately from the ion source, and by attaching and detaching the ion source to and from the analysis tube, the ion source and the gas inlet of the ionization chamber of Connection between the distal end of the gas inlet tube, a mass spectrometer, characterized in that separation is also provided with means for simultaneously achieved. 2. A tubular joint is slidably attached to the tip of the gas introduction pipe as a means for connecting and separating the gas introduction port of the ionization chamber of the ion source and the tip of the gas introduction pipe, and the tubular joint is attached. An elastic member is attached to the edge of the gas introduction port so as to come into pressure contact therewith.
The described mass spectrometer. 3. An ionization chamber of the ion source is provided with a gas discharge port for discharging a sample gas separately from the gas introduction port, and a gas discharge connected to a sample gas discharge system outside the analysis tube. The tube is attached to the analysis tube separately from the ion source with its tip protruding into the analysis tube, and the ion source is attached to and detached from the analysis tube to remove the gas in the ionization chamber of the ion source. The mass spectrometer according to claim 1 or 2, further comprising means for simultaneously connecting and disconnecting the discharge port and the tip of the gas discharge pipe. 4. A tubular joint is slidably attached to the distal end of the gas exhaust pipe as a means for connecting and disconnecting the gas exhaust port of the ionization chamber of the ion source and the distal end of the gas exhaust pipe, and the tubular joint is connected to the distal end of the gas exhaust pipe. 4. An elastic member which is brought into pressure contact with the edge of the gas outlet is attached.
The described mass spectrometer.