JP2021082497A - Mass spectroscope - Google Patents

Abstract

To provide a technique for facilitating attachment/detachment of a deliquoring tube for an ion source for a mass spectroscope.SOLUTION: A mass spectroscope includes an ionization chamber 22 for ionizing a sample component under atmospheric pressure and a vacuum chamber for introducing ions and performing mass spectrometry, and includes a vacuum chamber side front wall portion 10a having an ion receiving opening 100, an ionization chamber side rear wall portion 21 which is connected to the ion receiving opening 100 and has an ion introduction portion for transporting ions from the ionization chamber 22 to the vacuum chamber, and an ionization chamber 20 which has a holding portion for holding the ionization chamber side rear wall portion 21 so that the distance between the vacuum chamber side front wall portion 10a and the ionization chamber rear wall portion 21 is variable, forms the ionization chamber 22, is movably arranged between an analysis position for ionizing a sample and an open position where the ionization chamber side rear wall portion 21 is exposed, and pushes the ionization chamber side rear wall portion 10a to a position at a predetermined distance when moved from the open position to the analysis position.SELECTED DRAWING: Figure 3

Description

The present invention relates to a mass spectrometer, and more particularly to a mass spectrometer provided with an atmospheric pressure ion source.

In the mass spectrometer used for the liquid chromatograph mass spectrometer (LC-MS), a so-called atmospheric pressure ionization method is used to ionize the components in the eluate containing the components eluted from the column of the liquid chromatograph (LC). An ion source is used. As the atmospheric pressure ionization method, an electrospray ionization (ESI) method, an atmospheric pressure chemical ionization (APCI) method, an atmospheric pressure photoionization (APPI) method and the like are well known.

In a mass spectrometer equipped with such an atmospheric pressure ion source, ions derived from sample components generated inside an ionization chamber, which has a substantially atmospheric pressure atmosphere, are introduced into the vacuum chamber, and a quadrupole mass filter arranged in the vacuum chamber is used. It is separated and detected according to the mass-to-charge ratio (m / z) by a mass separator such as. Generally, the degree of vacuum in the vacuum chamber in which the mass separator is placed is very high, so in order to keep the degree of vacuum in this vacuum chamber high, between the high vacuum chamber in which the mass separator is placed and the ionization chamber. One or a plurality of intermediate vacuum chambers are provided in the vacuum chamber, and the degree of vacuum is gradually increased from the ionization chamber to the high vacuum chamber. Such a configuration is called a multi-stage differential exhaust system.

For example, in the mass spectrometer described in Patent Document 1, the ionization chamber and the first intermediate vacuum chamber in the next stage are communicated with each other by a small-diameter pipe called a desolving tube, and the ionization spray is charged and sprayed into the ionization chamber. The ions generated by the liquid sample are transported to the first intermediate vacuum chamber through the desolving tube. In some cases, charged droplets in which the solvent is not sufficiently vaporized may jump into the desolvation tube as they are, and in order to promote the vaporization of the solvent from these droplets and achieve ionization, the desolvation tube is provided around the tube. It is heated by a cartridge heater or the like.

In the conventional mass spectrometer described in Non-Patent Document 1 and the like, the space formed between the rear wall of the ionization chamber and the front wall of the first intermediate vacuum chamber (hereinafter referred to as “arrangement space”) is described above. A cartridge heater, wiring and connectors (in some cases, a circuit board) for supplying a heating current to the heater are arranged. Further, in this arrangement space, a gas pipe for ejecting dry gas from the periphery of the inlet of the desolvation tube into the ionization chamber in order to promote desolvation of charged droplets, and further, for ionization by the APCI method. In some cases, wiring or connectors for applying a high voltage to the needle electrode arranged in front of the spray flow from the spray in the traveling direction may be arranged.

In the mass analyzer described in Non-Patent Document 1, the DL flange that serves as the rear wall of the ionization chamber and to which the desolvation line (DL), which is the ion introduction portion, is attached, and the front wall of the first intermediate vacuum chamber. By fixing the DL flange to the vacuum flange with a plurality of hexagon socket bolts so that the distance from a certain vacuum flange is a predetermined interval, an arrangement space is provided between the ionization chamber and the first intermediate vacuum chamber. Is forming. In this configuration, by loosening the bolts and removing the DL flange, it is possible to perform maintenance on the desolvation pipe and the above-mentioned parts arranged in the arrangement space.

Japanese Unexamined Patent Publication No. 2015-5805

"LCMSTM-8060 Ultra High Speed Triple Quadrupole LC / MS / MS System}, [online], [Search November 1, 2019], Shimadzu Corporation, Internet <URL: https://www.an. shimadzu.co.jp/lcms/lcms8060/index.htm ＞

However, in the above-mentioned conventional mass spectrometer, since the DL flange is fixed to the vacuum flange with a bolt as described above, it is necessary to loosen the bolt with a tool when removing the DL flange, which is necessary for maintenance work. Take the trouble. In addition, when the analysis is performed, the temperature inside the ionization chamber becomes high, and the liquid sample sprayed from the ionization spray hangs on the head of the bolt protruding into the ionization chamber, which causes seizure of the bolt and makes it difficult to remove the bolt. There is. Further, when the person in charge wipes off the dirt on the DL flange, there is a problem that the head of the bolt becomes an obstacle and the dirt tends to remain. Furthermore, when attaching the DL flange, if a plurality of bolts are not fastened in a well-balanced manner, the DL flange may be tilted and damaged.

An object of the present invention is to provide a mass spectrometer that solves various problems caused by attaching a DL flange using bolts as described above and has good maintenance workability of the device. is there.

One aspect of the mass spectrometer according to the present invention, which has been made to solve the above problems, is an ionization chamber for ionizing a sample component under atmospheric pressure, and an ion generated in the ionization chamber is introduced into the ion or the ion or the ion. A mass spectrometer comprising a vacuum chamber for mass spectrometry of ions derived from the ions.
The front wall on the vacuum chamber side with an ion receiving opening,
An ionization chamber side rear wall portion connected to the ion receiving opening and having an ion introduction portion for transporting ions from the ionization chamber to the vacuum chamber, and a rear wall portion on the ionization chamber side.
A holding portion that holds the ionization chamber side rear wall portion with respect to the vacuum chamber side front wall portion so that the distance between the vacuum chamber side front wall portion and the ionization chamber rear wall portion is variable.
It forms the ionization chamber, is movably arranged between an analysis position for ionizing a sample and an open position where the rear wall portion on the ionization chamber side is exposed, and moves from the open position to the analysis position. At that time, the ionization chamber side rear wall portion comes into contact with the ionization chamber side rear wall portion held by the holding portion and the distance between the ionization chamber side rear wall portion and the vacuum chamber side front wall portion becomes a predetermined distance. Ionization chamber to push in and
Is provided.

In the above aspect of the mass spectrometer according to the present invention, the vacuum chamber side front wall portion and the ionization chamber side rear wall portion correspond to the vacuum flange and the DL flange in the above-mentioned conventional mass spectrometer, respectively.

Further, in the above aspect of the mass spectrometer according to the present invention, the vacuum chamber may be one chamber, but in general, when the atmospheric pressure ionization method is used as the ionization method, a configuration of a multi-stage differential exhaust system is adopted. Therefore, there are a plurality of vacuum chambers, and the vacuum chamber side front wall portion is a member constituting the front wall of the vacuum chamber at the frontmost stage (that is, the vacuum chamber having the lowest degree of vacuum).

In the mass spectrometer of the above aspect according to the present invention, when the operator closes the ionization chamber from the open state, that is, moves it to the analysis position, the rear wall portion on the ionization chamber side is moved to the front of the vacuum chamber side by the ionization chamber. It is pushed closer to the wall. When the ionization chamber is completely closed, the rear wall portion on the ionization chamber side is pushed to an appropriate position and positioned, and a space at a predetermined interval between the rear wall portion on the ionization chamber side and the front wall portion on the vacuum chamber side is provided. Is formed.

Therefore, according to the mass spectrometer of the above aspect according to the present invention, it is not necessary to fix the ionization chamber side rear wall portion to the vacuum chamber side front wall portion with another member such as a bolt as in the conventional case. Therefore, the iontophoresis portion provided on the rear wall portion on the ionization chamber side, the heater arranged in the space between the rear wall portion on the ionization chamber side and the front wall portion on the vacuum chamber side, various wirings, connectors, etc. When performing maintenance on gas pipes and the like, the front wall on the ionization chamber side can be easily removed without using tools, and maintenance work can be performed efficiently. Further, since the bolt head does not protrude toward the ionization chamber side, it is easy for the person in charge to wipe off the dirt on the rear wall portion on the ionization chamber side, and the dirt is less likely to remain. Furthermore, the rear wall portion on the ionization chamber side can be appropriately attached only by closing the ionization chamber, and problems such as damage to the rear wall portion on the ionization chamber side at the time of attachment can be avoided.

The external perspective view of the mass spectrometer which is one Embodiment of this invention. The block diagram of the main part of the mass spectrometer of this embodiment. The schematic block diagram around the ionization unit when the ionization chamber is in the analysis position in the mass spectrometer of this embodiment. The schematic block diagram around the ionization unit when the ionization chamber is in an open position in the mass spectrometer of this embodiment. The schematic block diagram around the ionization unit in the modification of the mass spectrometer of this embodiment. The schematic block diagram around the ionization unit in another modification of the mass spectrometer of this embodiment.

A mass spectrometer according to an embodiment of the present invention will be described with reference to the accompanying drawings.
This mass spectrometer is a single-type quadrupole mass spectrometer equipped with an atmospheric pressure ion source, and both the ESI method and the APCI method can be used as the atmospheric pressure ionization method.

[Overall configuration of the mass spectrometer of the present embodiment]
FIG. 1 is an external perspective view of the mass spectrometer of the present embodiment. FIG. 2 is a schematic configuration diagram of a main part of the mass spectrometer of the present embodiment. For convenience of explanation, as shown in FIG. 1, the X-axis, Y-axis, and Z-axis that are orthogonal to each other are defined. That is, the Z-axis direction is the height direction, the Y-axis direction is the depth direction, and the X-axis direction is the width direction.

As shown in FIG. 1, the mass spectrometer of the present embodiment has a substantially rectangular outer shape, and the ionization chamber 20 in which the ionization chamber is formed is projected forward. A vacuum chamber 10 having an elongated shape in the depth direction is arranged behind the ionization chamber 20. Further, a vacuum pump unit 50 for evacuating the inside of the vacuum chamber 10 is arranged below the vacuum chamber 10, and a circuit unit 60 in which various electric circuits are housed above and to the left of the vacuum chamber 10 is arranged. Is.

As shown in FIG. 2, the inside of the vacuum chamber 10 is divided into three chambers, a first intermediate vacuum chamber 11, a second intermediate vacuum chamber 12, and a high vacuum chamber 13 in the depth direction (Y-axis direction). Further, in front of the vacuum chamber 10, an ionization chamber 20 and a DL flange 21 that define an ionization chamber 22 inside are attached. The three chambers of the first intermediate vacuum chamber 11, the second intermediate vacuum chamber 12, and the high vacuum chamber 13 are evacuated by a vacuum pump installed in the vacuum pump unit 50 or outside the apparatus, respectively, and are evacuated in the first intermediate. The degree of vacuum is gradually increased in the vacuum chamber 11, the second intermediate vacuum chamber 12, and the high vacuum chamber 13. On the other hand, the ionization chamber 22 communicates with the outside, and the inside thereof has a substantially atmospheric pressure.

An ionization probe (spray) 23 for spraying a liquid sample is provided in the ionization chamber 22, and a needle electrode 27 for causing a corona discharge during ionization by the APCI method is arranged in front of the ionization probe 23. The ionization chamber 22 and the first intermediate vacuum chamber 11 communicate with each other through a small-diameter desolvation tube 24. A plurality of dry gas outlets 26 are provided around the ion introduction port 24a, which is the inlet of the desolvation pipe 24 on the ionization chamber 22 side, and heated inert gas such as nitrogen is discharged from the dry gas outlet 26. Squirt. Further, a cartridge heater 25 is provided around the desolvation tube 24, and the desolvation tube 24 is heated to a predetermined temperature by the cartridge heater 25.

A first ion guide 14 is arranged inside the first intermediate vacuum chamber 11, and the first intermediate vacuum chamber 11 and the second intermediate vacuum chamber 12 communicate with each other through a small hole formed at the top of the skimmer 15. A second ion guide 16 is arranged inside the second intermediate vacuum chamber 12, and the second intermediate vacuum chamber 12 and the high vacuum chamber 13 communicate with each other through a small hole formed in the center of the lens electrode 17. Inside the high vacuum chamber 13, a quadrupole mass filter 18 including a pre-rod electrode and a main rod electrode, and an ion detector 19 are arranged.

As shown in FIG. 2, the desolvation tube 24, the first ion guide 14, the skimmer 15, the second ion guide 16, the lens electrode 17, the quadrupole mass filter 18, and the ion detector 19 are generally linear ions. It is arranged along the optical axis C.

[Analytical operation of the mass spectrometer of the present embodiment]
The analysis operation in the mass spectrometer of the present embodiment will be briefly described.
The ionization probe 23 is supplied with an eluate containing components separated by a liquid chromatograph (LC) column (not shown). The ionization probe 23 sprays the eluate into the ionization chamber 22 which has a substantially atmospheric pressure atmosphere, and ionizes the sample components contained in the eluate.

When the ESI method is used as the ionization method, a high voltage is applied to the tip of the ionization probe 23. The liquid sample is sprayed while being given a biased charge by the electric field formed by the voltage, and the sample components are ionized in the process of vaporizing the solvent in the sprayed charged droplets. On the other hand, when the APCI method is used as the ionization method, instead of applying a high voltage to the tip of the ionization probe 23, a high voltage is applied to the needle electrode 27 to cause a corona discharge. By this corona discharge, the solvent gas generated from the droplets sprayed from the ionization probe 23 is ionized, and the component molecules are ionized by a chemical reaction between the solvent ions and the component molecules.

The ions derived from the sample components generated in the ionization chamber 22 as described above are sucked into the desolvation tube 24 from the ion introduction port 24a on the gas flow generated by the pressure difference between both ends of the desolvation tube 24. When the charged droplet in which the solvent is not sufficiently vaporized approaches the ion introduction port 24a, it is exposed to the dry gas blown out from the dry gas outlet 26, so that the vaporization of the solvent is promoted and the ionization proceeds. Furthermore, even when charged droplets in which the solvent is not sufficiently vaporized are sucked into the desolvation tube 24, desolvation proceeds in the desolvation tube 24 which is at a high temperature, and ionization is promoted.

The ions thus sent into the first intermediate vacuum chamber 11 through the solvent removal tube 24 are sent to the high vacuum chamber 13 via the first ion guide 14, the skimmer 15, the second ion guide 16, and the lens electrode 17. It is introduced into the multi-pole mass filter 18. Only ions having a specific mass-to-charge ratio corresponding to the voltage applied to the rod electrode pass through the quadrupole mass filter 18, and other ions are emitted on the way. The ion detector 19 detects ions that have passed through the quadrupole mass filter 18 and outputs a detection signal according to the amount of the ions.

In this way, in the mass spectrometer of the present embodiment, the ions derived from the sample components generated in the ionization chamber 22 located on the foremost side when viewed from the operator are introduced into the vacuum chamber 10 behind the sample component. It is sent from the front side to the rear side. The sent ions are separated by the quadrupole mass filter 18 according to the mass-to-charge ratio, and then detected by the ion detector 19 in the final stage.

[Detailed configuration around the ionization unit]
As described above, since the eluate is sprayed from the ionization probe into the ionization chamber 22 at the time of analysis, the eluate adheres to the inner wall of the ionization chamber 22 and the members arranged in the ionization chamber 22 and becomes dirty. In addition, the eluate also adheres to the inside of the solvent removal tube 24 and becomes dirty. Furthermore, it is also necessary to maintain the members arranged in the space between the ionization chamber 22 and the vacuum chamber 10 (first intermediate vacuum chamber 11), such as the cartridge heater 25 and the gas pipe for supplying the drying gas. Therefore, in the mass spectrometer of the present embodiment, the ionization chamber 20 can be opened and the DL flange 21 can be removed forward with the ionization chamber 20 open. Next, the configuration around this ionization unit will be described in detail.

FIG. 3 is a schematic configuration diagram of the periphery of the ionization unit when the ionization chamber is in the analysis position in the mass spectrometer of the present embodiment. FIG. 4 is a schematic configuration diagram of the periphery of the ionization unit when the ionization chamber is in the open position in the mass spectrometer of the present embodiment.
3 and 4 are schematic cross-sectional views of the mass spectrometer of the present embodiment when viewed from above, but the internal structure is shown in an easy-to-see manner, and the surface is not necessarily parallel to the XY plane. It is not a cross section of. In addition, some are shown briefly.

The ionization chamber 20 is a substantially box-shaped member that forms five surfaces other than the rear surface, that is, the bottom surface, the top surface (upper surface), both side surfaces, and the front surface of the ionization chamber 22. The DL flange 21 is a substantially flat plate-shaped member that forms the rear surface of the ionization chamber 22. The ionization chamber 20 and the DL flange 21 are made of a metal such as stainless steel. The vacuum flange 10a is a member that constitutes the front wall of the first intermediate vacuum chamber 11 in the vacuum chamber 10.

The ionization chamber 20 is attached to the vacuum flange 10a via a hinge 200 extending in the vertical direction (Z-axis direction). The ionization chamber 20 is hingeable around the hinge 200, and in the state shown in FIG. 3 (that is, the analysis position), the ionization chamber 20 defines the ionization chamber 22 together with the DL flange 21. On the other hand, in the state shown in FIG. 4 (open position), the ionization chamber 20 is open and the DL flange 21 is almost completely exposed. Further, the ionization chamber 20 is provided with a lock mechanism 28 for fixing the position of the chamber 20 in a state where the ionization chamber 20 is moved to the analysis position. The lock mechanism 28 may be provided on the vacuum flange 10a, the exterior cover, or the like.

A solvent removal unit 210 is attached to the substantially center of the DL flange 21. The desolvation unit 210 includes a desolvation pipe 24 extending in the Y-axis direction, a cartridge heater 25 through which the desolvation pipe 24 penetrates, and an internal gas pipeline 211 for guiding the dry gas to the dry gas outlet 26. .. The solvent removal tube 24 is made of a metal such as stainless steel. The cartridge heater 25 includes a substantially columnar heating block formed of a metal having high thermal conductivity such as aluminum, and a heater for heating the heating block. A through hole is formed in the heating block in the flow direction, and the desolvation tube 24 is inserted so as to come into contact with the inner peripheral surface of the through hole.

The tip of the desolvation tube 24 on the side opposite to the ion introduction port 24a protrudes to the rear side of the desolvation unit 210, and a flange member 212 is attached to this tip. The flange member 212 is a tubular member through which the desolvation pipe 24 penetrates, and the plate-shaped portion 212a projecting outward is in contact with the end surface 25a of the heating block of the cartridge heater 25. A sealing member 213 such as an O-ring is provided on the plate-shaped portion 212a of the flange member 212 on the surface opposite to the contact surface with the end surface 25a of the heating block.

An ion receiving opening 100 having an inner diameter slightly larger than the outer diameter of the tubular portion 212b of the flange member 212 is bored at substantially the center of the vacuum flange 10a. As shown in FIG. 3, when the DL flange 21 is pushed most to the back side, the tip of the desolvation tube 24 is inserted into the ion receiving opening 100 and protrudes into the first intermediate vacuum chamber 11. Further, in the state where the DL flange 21 is pushed to the back side in this way, the seal member 213 comes into contact with the front surface of the vacuum flange 10a. When the DL flange 21 is pushed in, the sealing member 213 is crushed and the gap between the vacuum flange 10a and the flange member 212 is closed.

On the front surface of the vacuum flange 10a, a gas pipe relay portion 110 and a high voltage wiring relay portion 120 are provided on both sides of the ion receiving opening 100. The gas pipe relay unit 110 has a gas supply port on the side, and a gas pipe for supplying dry gas from the outside is connected to the gas supply port. Further, the gas pipe relay portion 110 has a gas pipe portion that opens forward and has a connecting shaft that protrudes forward. Further, the high-voltage wiring relay unit 120 is provided with high-voltage wiring inside, and has a connecting shaft protruding forward. This high voltage wiring is connected to an external high voltage power supply from the vacuum flange 10a side.

On the other hand, the DL flange 21 is provided with a gas pipe secondary relay unit 220 and a high voltage wiring secondary relay unit 221 at positions corresponding to the gas pipe relay unit 110 and the high voltage wiring relay unit 120 of the vacuum flange 10a, respectively. Has been done. That is, the gas pipe secondary relay unit 220 and the high voltage wiring secondary relay unit 221 are provided on both sides of the solvent removal unit 210.
The gas pipe secondary relay unit 220 has a connected shaft into which the connection shaft of the gas pipe relay unit 110 on the vacuum flange 10a side is inserted. The connected shaft is provided with a gas pipe inside, and when the connected shaft is inserted to a certain depth in the connected shaft, both gas pipes are connected. Further, the gas pipe of the gas pipe secondary relay unit 220 is connected to the internal gas pipe line 211 of the desolving unit 210 by another gas pipe.

The high-voltage wiring secondary relay unit 221 also has a connected shaft into which the connection shaft of the high-voltage wiring relay unit 120 on the vacuum flange 10a side is inserted. The connected shaft is provided with high-voltage wiring inside, and when the connecting shaft is inserted into the connected shaft to a certain depth, both high-voltage wirings are connected. Further, the high voltage wiring is arranged up to the front side of the DL flange 21 and is connected to the needle electrode 27. Further, a ball plunger 221a for holding the inserted connecting shaft is built in the connected shaft of the high voltage wiring secondary relay unit 221. Therefore, when the connecting shaft of the high-voltage wiring relay unit 120 is inserted into the connected shaft of the high-voltage wiring secondary relay unit 221, the connecting shaft is slidably held in the Y-axis direction by the ball plunger 221a. This makes it difficult for the connecting shaft to come off from the connected shaft, and as will be described later, it is possible to prevent the DL flange 21 from falling off when the DL flange 21 is attached.

In this embodiment, the ball plunger is provided only on the connected shaft of the high voltage wiring secondary relay unit 221. However, the ball plunger may also be provided on the connected shaft of the gas pipe secondary relay unit 220. Thereby, the DL flange 21 can be more reliably prevented from falling off.

As shown in FIG. 4, the DL flange 21 is not fixed in the Y-axis direction when the lock by the lock mechanism 28 is released and the ionization chamber 20 is opened. Therefore, as shown by the arrow B in FIG. 4, the DL flange 21 is movable, and when the operator pulls out the DL flange 21 toward the front side, the connection between the gas pipe relay unit 110 and the gas pipe secondary relay unit 220 is established. , And the connection between the high-voltage wiring relay unit 120 and the high-voltage wiring secondary relay unit 221 can be disconnected, and the tip of the desolving pipe 24 can be pulled out from the ion receiving opening 100 to take out the DL flange 21. it can. In this way, the DL flange 21 is removed to the outside to perform maintenance on the desolvation pipe 24 and the cartridge heater 25 attached to the DL flange 21, and parts provided on the front surface of the exposed vacuum flange 10a. Etc. can be performed.

After the maintenance work is completed, the operator inserts the tip of the desolving pipe 24 into the ion receiving opening 100 of the vacuum flange 10a, and the gas pipe relay part 110, the gas pipe secondary relay part 220, and the high voltage wiring relay are relayed. A DL flange 21 to which the unit 120 and the high-voltage wiring secondary relay unit 221 are connected is attached. Since the gas piping secondary relay section 220 and the high voltage wiring secondary relay section 221 are located on both sides of the solvent removal unit 210, the gas piping secondary relay section 220 and the high voltage wiring secondary relay section 221 The DL flange 21 is suitable for the vacuum flange 10a by aligning the two shafts so that the respective connected shafts of the above and the respective connecting shafts of the gas pipe relay unit 110 and the high voltage wiring relay unit 120 are fitted to each other. Can be installed in any position. That is, the DL flange 21 can be positioned by the two axes.

Further, when the high voltage wiring relay unit 120 and the high voltage wiring secondary relay unit 221 are fitted as described above, the high voltage wiring secondary relay unit 221 is held by the ball plunger 221a with respect to the high voltage wiring relay unit 120. Therefore, the DL flange 21 is held without falling off from the vacuum flange 10a without pressing the DL flange 21 to the back side.

After mounting the DL flange 21 on the vacuum flange 10a as described above, the operator closes the ionization chamber 20 to the analysis position and locks it by the lock mechanism 28 as shown in FIG. When the ionization chamber 20 is closed, the gasket 222 attached to the ionization chamber 20 comes into contact with the front surface of the DL flange 21, and the gasket 222 is crushed to press the DL flange 21 rearward. The pushed DL flange 21 retracts so as to approach the vacuum flange 10a, and the seal member 213 attached to the flange member 212 comes into contact with the front surface of the vacuum flange 10a.

When the ionization chamber 20 is completely closed by being locked by the lock mechanism 28, the seal member 213 is sufficiently crushed by being pushed by the heating block of the cartridge heater 25. As a result, the gap between the ion receiving opening 100 and the flange member 212 is closed by the seal member 213, and the first intermediate vacuum chamber 11 becomes airtight. At this time, the distance d between the DL flange 21 and the vacuum flange 10a is approximately determined by the length of the cartridge heater 25 in the Y-axis direction.

When the DL flange 21 is sufficiently pushed in and comes to a predetermined position in this way, the gas pipe on the vacuum flange 10a side and the gas pipe on the DL flange 21 side are sufficiently connected, and the vacuum flange is sufficiently connected from the external dry gas supply source. The gas supplied to 10a is ejected from the dry gas ejection port 26 into the ionization chamber 22 via the gas pipe relay section 110 → the gas piping secondary relay section 220 → the internal gas pipeline 211 of the desolving unit 210. On the other hand, the power for corona discharge supplied from the external high-voltage power supply to the vacuum flange 10a is supplied to the needle electrode 27 via the high-voltage wiring relay unit 120 → the high-voltage wiring secondary relay unit 221 to cause corona discharge. Will be done. By surely pushing the DL flange 21 to a predetermined position by the ionization chamber 20 in this way, both the gas pipe and the high voltage wiring are surely connected, and gas and electric power are supplied.

As described above, in the mass spectrometer of the present embodiment, it is not necessary to fix the DL flange 21 to the vacuum flange 10a by using parts such as bolts that require a tool for attachment / detachment. Therefore, the work of attaching and detaching the DL flange 21 is easy, and the labor required for maintenance can be reduced. In addition, it is possible to avoid a situation in which the DL flange 21 is difficult to remove due to seizure of bolts or the like. Further, since the head of the bolt for attaching the DL flange 21 does not protrude into the ionization chamber 22, it is possible to easily wipe off the dirt on the front surface of the DL flange 21 and reduce the remaining dirt.

It is clear that the above embodiment is merely an example of the present invention, and is included in the claims of the present application even if it is further modified, added, or modified as appropriate within the scope of the present invention.

For example, in the above embodiment, the position of the DL flange 21 with respect to the vacuum flange 10a is determined by two shafts, a gas pipe and a high voltage wiring, but the number of shafts may be three or more. Further, the high voltage wiring may not be for corona discharge, but may be wiring for applying a high voltage to the tip of the ionization probe 23 for ionization by the ESI method.
Further, in the above embodiment, the cartridge heater 25 pushes the vacuum flange 10a via the seal member 213 when the DL flange 21 is pushed in, but a member other than the cartridge heater 25 may push the vacuum flange 10a.

Further, in the mass spectrometer of the above embodiment, the DL flange 21 defines the ionization chamber 22 together with the ionization chamber 20, but substantially only the ionization chamber 20 defines the ionization chamber 22, and the DL flange 21 is ionized. It may be outside the chamber 22. FIG. 5 is a schematic configuration diagram around the ionization unit in one modification. In this example, the ionization chamber 20 has a rear wall surface 20a, and the rear surface 20a is formed with a protrusion in front of the solvent removal unit 210 and an opening or notch through which the needle electrode 27 and its holder can be inserted. There is. When the ionization chamber 20 is closed, the DL flange 21 is pushed backward by the rear wall surface 20a and is settled in a predetermined position, which is the same as the above embodiment.

Further, in the mass spectrometer of the above embodiment, the ionization chamber 20 is freely attached to the vacuum flange 10a via the hinge 200, but even if it does not have such a structure, it can be attached to the vacuum flange 10a or the exterior of the device from the front. Any structure may be used as long as the ionization chamber 20 can be attached. FIG. 6 is a schematic configuration diagram around the ionization unit in one modification. In this example, the ionization chamber 20 is attached to the vacuum flange 10a by two (or more) locking mechanisms 29. Reference numeral 29'in FIG. 6 indicates a state in which the lock mechanism 29 is unlocked. As described above, in the unlocked state, the ionization chamber 20 can be removed forward. Even in this case, when the ionization chamber 20 is attached to an appropriate position, the DL flange 21 is pushed backward and is settled in the predetermined position, which is the same as the above embodiment.

Further, the above embodiment is an example in which the present invention is applied to a single type quadrupole mass spectrometer, but the present invention is another type of mass spectrometer using an atmospheric pressure ion source, specifically, a mass spectrometer of another type. , Triple quadrupole mass spectrometer, etc.
The atmospheric pressure ion source is not limited to the ESI method and the APCI method, but the atmospheric pressure photoionization (APPI) method, the probe electrospray ionization (PESI) method, the desorption electrospray ionization (DESI) method, and the like can also be used. it can.

[Various aspects]
It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following embodiments.

(Item 1) In one aspect of the mass spectrometer according to the present invention, an ionization chamber for ionizing a sample component under atmospheric pressure and an ion generated in the ionization chamber are introduced and derived from the ion or the ion. A mass spectrometer equipped with a vacuum chamber for mass spectrometry of ions.
The front wall on the vacuum chamber side with an ion receiving opening,
An ionization chamber side rear wall portion connected to the ion receiving opening and having an ion introduction portion for transporting ions from the ionization chamber to the vacuum chamber, and a rear wall portion on the ionization chamber side.
A holding portion that holds the ionization chamber side rear wall portion with respect to the vacuum chamber side front wall portion so that the distance between the vacuum chamber side front wall portion and the ionization chamber rear wall portion is variable.
It forms the ionization chamber, is movably arranged between an analysis position for ionizing a sample and an open position where the rear wall portion on the ionization chamber side is exposed, and moves from the open position to the analysis position. At that time, the ionization chamber side rear wall portion comes into contact with the ionization chamber side rear wall portion held by the holding portion and the distance between the ionization chamber side rear wall portion and the vacuum chamber side front wall portion becomes a predetermined distance. Ionization chamber to push in and
Is provided.

According to the mass spectrometer according to the first item, it is not necessary to fix the rear wall portion on the ionization chamber side to the front wall portion on the vacuum chamber side with a bolt as in the conventional case. Therefore, no tools are used when performing maintenance on the cartridge heater, various wiring, connectors, gas piping, etc. located in the space between the rear wall on the ionization chamber side and the front wall on the vacuum chamber side. The rear wall on the ionization chamber side can be easily removed, and maintenance work can be performed efficiently. Further, since the bolt head does not protrude toward the ionization chamber side, it is easy for the person in charge to wipe off the dirt on the rear wall portion on the ionization chamber side, and the dirt is less likely to remain. Furthermore, the rear wall portion of the ionization chamber can be attached to an appropriate position only by closing the ionization chamber, and problems such as damage to the rear wall portion on the ionization chamber side can be prevented.

(Item 2) In the mass spectrometer according to the item 1, the ionization chamber can be attached to the front wall portion on the vacuum chamber side in a butterfly motion.

According to the mass spectrometer according to the second item, the operator can easily open and close the ionization chamber. Further, since the ionization chamber is not removed from the main body of the apparatus, it is not necessary to secure a place for storing the ionization chamber during maintenance work.

(Item 3) In the mass spectrometer according to the first or second item, the lock portion that locks the ionization chamber to a closed state in a state where the ionization chamber pushes the rear wall portion on the ionization chamber side to a predetermined position. , Can be further prepared.

According to the mass spectrometer according to the third item, the operator can completely close the ionization chamber by the lock portion, so that the rear wall portion on the ionization chamber side can be fixed in a predetermined position.

(Item 4) In the mass spectrometer according to any one of items 1 to 3, the rear wall portion on the ionization chamber side has a gas outlet for ejecting gas into the ionization chamber.
The holding portion may be connected to a gas pipe that transports the gas ejected from the gas ejection port from the front wall portion side on the vacuum chamber side to the rear wall portion side on the ionization chamber side.

(Item 5) In the mass spectrometer according to any one of items 1 to 3, the ionization chamber ionizes a sample component by an atmospheric chemical ionization method.
A needle electrode that causes a corona discharge is provided on the rear wall on the ionization chamber side.
The holding portion may be connected to an electric wiring that supplies electric power for applying a high voltage to the needle electrode from the front wall portion side on the vacuum chamber side to the rear wall portion side on the ionization chamber side.

According to the mass spectrometer according to the fourth or fifth paragraph, the gas or electric power supply path supplied from the outside to the ionization chamber is held by the rear wall portion on the ionization chamber side with respect to the front wall portion on the vacuum chamber side. It can be used as a holding part.

(Section 6) In the mass spectrometer according to any one of paragraphs 1 to 5,
The ionization chamber ionizes the sample components by the atmospheric pressure chemical ionization method.
The rear wall portion on the ionization chamber side has a gas outlet for ejecting gas into the ionization chamber, and the rear wall portion on the ionization chamber side is provided with a needle electrode for causing a corona discharge.
Electric power for applying a high voltage to the needle electrode and the connection part that connects the gas pipe that transports the gas ejected from the gas outlet from the front wall side on the vacuum chamber side to the rear wall side on the ionization chamber side. The connection portion for connecting the electrical wiring for supplying the electric wiring from the front wall portion on the vacuum chamber side to the rear wall portion on the ionization chamber side sandwiches the ion introduction portion arranged in the center of the rear wall portion on the front ionization chamber side. It can be provided on both sides with.

According to the mass spectrometer according to the sixth item, the rear wall portion on the ionization chamber side can be positioned on two axes with respect to the front wall portion on the vacuum chamber side. As a result, the position of the rear wall portion on the ionization chamber side is reliably determined in the circumferential direction centered on the iontophoresis portion, and the rear wall portion on the ionization chamber side can be accurately attached to the front wall portion on the vacuum chamber side.

(Section 7) In the mass spectrometer according to any one of paragraphs 1 to 6, the holding portion faces both the front wall portion on the vacuum chamber side and the rear wall portion on the ionization chamber side. The protrusion provided on one side of the surface may be held by a ball plunger provided on the other side.

According to the mass spectrometer according to the seventh item, the rear wall portion on the ionization chamber side can be pushed to an appropriate position by the ionization chamber while avoiding the rear wall portion on the ionization chamber side from falling off.

(Item 8) In the mass spectrometer according to any one of items 1 to 7, the ion introduction section includes a conduit through which ions pass and a heater portion surrounding the conduit. In a state where the ionization chamber pushes the rear wall portion on the ionization chamber side, the tip end portion of the pipeline is inserted into the ion receiving opening, and the tip end of the heater portion passes through the seal member to the front wall on the vacuum chamber side. It can be in contact with the portion.

According to the mass spectrometer according to the eighth item, the airtightness of the vacuum chamber provided with the ion receiving opening by the sealing member can be ensured while appropriately connecting the ion introducing portion and the ion receiving opening. ..

10 ... Vacuum chamber 10a ... Vacuum flange 100 ... Ion receiving opening 11 ... First intermediate vacuum chamber 20 ... Ionization chamber 20a ... Rear wall surface 110 ... Gas piping relay unit 120 ... High voltage wiring relay unit 200 ... Hinge 21 ... DL flange 210 ... Desolving unit 211 ... Internal gas pipe 212 ... Flange member 212a ... Plate-shaped part 212b ... Cylindrical part 213 ... Sealing member 22 ... Ionization chamber 220 ... Gas piping secondary relay part 221 ... High-voltage wiring secondary relay part 221a ... Ball plunger 222 ... Gasket 23 ... Ionization probe 24 ... Desolving pipe 24a ... Ion inlet 25 ... Cartridge heater 25a ... End face 26 ... Dry gas outlet 27 ... Needle electrodes 28, 29 ... Lock mechanism

Claims (8)

A mass spectrometer including an ionization chamber for ionizing sample components under atmospheric pressure and a vacuum chamber for mass spectrometry of the ions or ions derived from the ions into which the ions generated in the ionization chamber are introduced. And
The front wall on the vacuum chamber side with an ion receiving opening,
An ionization chamber side rear wall portion connected to the ion receiving opening and having an ion introduction portion for transporting ions from the ionization chamber to the vacuum chamber, and a rear wall portion on the ionization chamber side.
A holding portion that holds the ionization chamber side rear wall portion with respect to the vacuum chamber side front wall portion so that the distance between the vacuum chamber side front wall portion and the ionization chamber rear wall portion is variable.
It forms the ionization chamber, is movably arranged between an analysis position for ionizing a sample and an open position where the rear wall portion on the ionization chamber side is exposed, and moves from the open position to the analysis position. At that time, the ionization chamber side rear wall portion comes into contact with the ionization chamber side rear wall portion held by the holding portion and the distance between the ionization chamber side rear wall portion and the vacuum chamber side front wall portion becomes a predetermined distance. Ionization chamber to push in and
A mass spectrometer equipped with. The mass spectrometer according to claim 1, wherein the ionization chamber is attached to the front wall portion on the vacuum chamber side in a butterfly motion. The mass spectrometer according to claim 1 or 2, further comprising a lock portion that locks the ionization chamber in a closed state in a state where the ionization chamber pushes the rear wall portion on the ionization chamber side to a predetermined position. The rear wall portion on the ionization chamber side has a gas outlet for ejecting gas into the ionization chamber.
The holding portion is any of claims 1 to 3, wherein the holding portion connects a gas pipe that transports the gas ejected from the gas ejection port from the front wall portion side on the vacuum chamber side to the rear wall portion side on the ionization chamber side. The mass spectrometer according to item 1. The ionization chamber ionizes the sample components by the atmospheric pressure chemical ionization method.
A needle electrode that causes a corona discharge is provided on the rear wall on the ionization chamber side.
The holding portion connects an electric wiring for supplying electric power for applying a high voltage to the needle electrode from the front wall portion side on the vacuum chamber side to the rear wall portion on the ionization chamber side. The mass spectrometer according to any one of 3. The ionization chamber ionizes the sample components by the atmospheric pressure chemical ionization method.
The rear wall portion on the ionization chamber side has a gas outlet for ejecting gas into the ionization chamber, and the rear wall portion on the ionization chamber side is provided with a needle electrode for causing a corona discharge.
Power for applying a high voltage to the needle electrode and the connection part that connects the gas pipe that transports the gas ejected from the gas outlet from the front wall side on the vacuum chamber side to the rear wall side on the ionization chamber side. The connection portion for connecting the electrical wiring for supplying the electric wiring from the front wall portion on the vacuum chamber side to the rear wall portion on the ionization chamber side sandwiches the ion introduction portion arranged in the center of the rear wall portion on the ionization chamber side. The mass spectrometer according to any one of claims 1 to 5, which is provided on both sides of the above. The holding portion holds a protruding portion provided on one of the facing surfaces of both the front wall portion on the vacuum chamber side and the rear wall portion on the ionization chamber side with a ball plunger provided on the other side. The mass spectrometer according to any one of claims 1 to 6. The ion introduction portion includes a conduit through which ions pass and a heater portion surrounding the conduit, and the tip of the conduit is in a state where the ionization chamber pushes the rear wall portion on the ionization chamber side. The mass spectrometer according to any one of claims 1 to 7, wherein the tip of the heater portion is inserted into the ion receiving opening and the tip of the heater portion abuts on the front wall portion on the vacuum chamber side via a sealing member.

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