JP2006260873A - Time-of-flight mass spectrometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To pass product ions generated in a specific split path without changing the voltage of a fan-shaped electric field regarding a time-of-flight mass spectrometer. <P>SOLUTION: In the time-of-flight mass spectrometer (TOFMS) having at least one fan-shaped electric field, a box (potential lift) 10 for changing potential arbitrarily arranged in front of at least one fan-shaped electric field for composing a fan-shaped electric field TOFMS, and a potential changing means for changing potential while a target ion passes the potential lift 10 are provided. An electrode 11 for re-acceleration having the same potential as a fan-shaped electric field inlet shunt is arranged between the exit of the potential lift 10 and the fan-shaped electric field inlet shunt, and ions are accelerated again by the potential difference between the outlet of the potential lift 10 and the electrode 11 for re-acceleration. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a time-of-flight mass spectrometer (TOFMS).

There is MS / MS measurement as a method of structural analysis using a mass spectrometer. FIG. 8 is an explanatory diagram of MS / MS measurement. This is a method in which a specific precursor ion is selected, spontaneously or forcibly cleaved, and structural analysis is performed from the pathway. Here, the precursor ion refers to a specific ion generated by an ion source. Product ions are generated when cleavage occurs. Here, it is expressed as “product ion nm _n ” as an identification symbol of the product ion generated by the cleavage of the precursor ion. Here, “n” is the number of cleavages, and “m _n ” is the number of paths for the n-th cleavage. In the case shown in FIG. 8, the precursor ions generate product ions 11, 12, 13,... All of these product ions are subjected to mass spectrometry.

As an advanced type, there is a method of further cleaving a product ion generated by fission and examining its route, which is called MS ³ measurement. FIG. 9 is an explanatory diagram of MS ³ measurement. In FIG. 9, product ions 21, 22, 23,... Are generated by two cleavages. In this way, the method of selecting the product ions in order and examining the cleavage pathways cleaved (n-1) times is called MS ⁿ measurement. In the figure, (n-1) times of cleavage has occurred. And the cleavage of the cleavage (n-1) circuit has occurred. All of the (n-1) -th cleavage product ions are subjected to mass spectrometry.

As a conventional technology, an ion trap type, quadrupole type, magnetic field type, and time-of-flight type mass spectrometer are combined to enable MS / MS measurement, and (n-2) times of cleavage with an ion trap. There is an apparatus that enables MS ⁿ by sequentially selecting product ions, measuring the mass of all product ions generated by the (n−1) -th cleavage with a time-of-flight mass spectrometer. FIG. 10 is an explanatory diagram of MS ⁿ measurement.

  On the other hand, in the TOFMS, a linear type and a reflected electric field type are mainstream. The linear type cannot perform MS / MS measurement in principle. The reflected electromagnetic field type is often used for MS / MS measurement because the time passing through the reflected electric field depends on the kinetic energy and mass of ions. In general, in TOFMS, the mass resolution improves as the flight distance (time of flight) increases.

  However, in a linear type or reflected electric field type TOFMS, increasing the flight distance leads to an increase in the size of the apparatus. A fan-shaped (sector-type) electric field-type TOFMS has solved this problem, and a plurality of fan-shaped electric fields are used to realize a long trajectory with a small device area (see Non-Patent Document 1, for example). In addition, as a development, there are devices that have succeeded in extending the flight time by making multiple orbits of the same trajectory and realizing a small size and high mass resolution (hereinafter referred to as the same trajectory type) (for example, Patent Documents) 1 and 2). As a modification, there is a spiral trajectory type in which the starting point and end point of each round are shifted in the direction perpendicular to the trajectory plane (see, for example, Patent Document 3). An apparatus capable of performing MS / MS measurement by combining the sector electric field type TOFMS and the reflected electric field type TOFMS has been developed.

  Next, the potential lift will be described. The potential lift is characterized by disposing a box capable of changing the potential in the free space of the mass spectrometer and changing the potential while ions pass through the box (see, for example, Patent Document 4).

In addition, a conductive box is set up in which ions can enter and exit within the time of flight, and the inside of the box has a uniform potential, and the potential of the box varies depending on whether the specific ions are incident or emitted. Such a device has been developed (see, for example, Patent Document 5).
T. T. et al. Sakurai et rl hu J. et al. Mass Spectron. Ion Proc 66, 283 (1985) JP 11-297257 A (paragraph 0026 to paragraph 0038, FIG. 1) Japanese Patent Laid-Open No. 11-135061 (paragraphs 0032 to 0042, FIG. 1) JP 2000-243345 A (paragraphs 0010 to 0018, FIG. 1) Japanese Patent Laid-Open No. 10-134664 (paragraphs 0008 to 0015, FIG. 1) Japanese Patent No. 3354427 (paragraphs 0006 to 0008, FIG. 1)

  Although the sector electric field type TOFMS has an advantage that a small size and high resolution can be realized, there is a problem that the product ions generated by the cleavage in flight cannot be passed without the sector electric field switching. The reason is described below. In the following description, the charges of all ions are monovalent. The configuration is shown in FIG.

  FIG. 11 is a conceptual diagram of an apparatus combining a sector electric field type TOFMS and a reflected electric field type TOFMS. In the figure, 1 is an ion source that emits ions, 2 is a first collision chamber (hereinafter abbreviated as collision chamber 1) that cleaves ions emitted from the ion source 1, and 3 is an ion emitted from the collision chamber 1. Passing sector electric field (fan-shaped electric field), 4 is an ion gate that blocks the passage of specific ions among the ions that have passed through the sector electric field 3, and 5 is a second collision chamber that cleaves ions that have passed through the ion gate 4. (Hereinafter abbreviated as collision chamber 2), 6 is a reflectron (reflective electric field) in which ions emitted from the collision chamber 2 are introduced and reflected.

The apparatus shown in FIG. 11 is a combination of a sector electric field type TOFMS composed of one sector electric field 3 and a reflected electric field type TOFMS composed of one reflectron 6, and this combination will be described. In the apparatus configured as described above, the precursor ions generated by the ion source 1 are accelerated by the acceleration voltage V ₀ . At this time, the kinetic energy E _{0 of the} ions is represented by E ₀ = eV ₀ . Here, e is the charge of electrons.

The electric sector is set so that ions having the kinetic energy E ₀ of the precursor ions can pass through. When a certain precursor ion (mass M ₀ ) is cleaved in the collision chamber 1 in front of the sector electric field to generate product ion 1 (mass M ₁ ), the kinetic energy E ₁ of the product ion is expressed by the following equation.

E ₁ = E ₀ × (M ₁ / M ₀ )
Since the sector electric field acts as an energy filter, the generated product ions cannot pass through the sector electric field. In order to pass the product ions, the sector electric field voltage must be changed so that ions having the kinetic energy of E ₁ can pass through until the sector electric field is reached. Thereafter, the product ions that have passed through the electric sector are introduced into the collision chamber 2 and cleaved. In principle, MS ³ can be measured by mass-analyzing all the product ions generated by this cleavage with a reflected electric field type TOFMS. However, this method has several problems. The problems are listed below.
1. If a sector electric field is used as a switching power supply, the voltage accuracy is reduced and the device becomes unstable.
2. The voltage of the reflected electric field needs to be switched according to the value of the kinetic energy (that is, the splitting path) of the product ion 1 (the precursor ion of the cleavage just before the reflected electric field). As a result, like the problem 1, the voltage accuracy is lowered and the device becomes unstable.
3. When MS ⁿ measurement is considered by increasing the number of cleavage means and sector electric field, the kinetic energy of ions detected by the detector decreases due to multiple cleavages, the detection sensitivity decreases, and in some cases detection is impossible. .

As described above, in the conventional apparatus, in actuality, when the sector electric field type TOFMS and the reflected electric field type TOFMS are combined, only MS / MS measurement is possible.
The present invention has been made in view of such a problem, and is capable of passing a product ion generated in a specific splitting path without changing the voltage of a sector electric field. The purpose is to provide a total.

  (1) The invention according to claim 1 is a time-of-flight mass spectrometer (TOFMS) having one or more fan-shaped electric fields, and is disposed in front of one or more fan-shaped electric fields constituting the fan-shaped electric field type TOFMS. In addition, a box (potential lift) in which the potential can be arbitrarily changed and a potential changing means for changing the potential while the target ions pass through the potential lift are provided, and between the potential lift outlet and the fan-shaped electric field inlet shunt. In addition, a reacceleration electrode having the same potential as that of the fan-shaped electric field inlet shunt is arranged, and ions are reaccelerated by a potential difference between the potential lift outlet and the reacceleration electrode.

(2) The invention described in claim 2 is characterized in that one or more ion-cleaving means are arranged in front of the one or more potential lifts.
(3) The invention according to claim 3 is characterized in that the plurality of cleavage means have different structures.

(4) The invention according to claim 4 is characterized in that the time-of-flight mass spectrometer and another mass spectrometer are combined.
(5) The invention according to claim 5 is characterized in that the another mass spectrometer is a TOFMS having a reflected electric field.

(6) The invention according to claim 6 is characterized in that the another mass spectrometer is a magnetic field type mass spectrometer.
(7) The invention according to claim 7 is characterized in that one or more cleaving means are arranged between the two mass spectrometers.

(8) The invention according to claim 8 is characterized in that the time-of-flight mass spectrometer and a device capable of separately measuring kinetic energy are combined.
(9) The invention according to claim 9 is characterized in that the apparatus capable of separating and measuring the kinetic energy is a sector electric field.

  (10) The invention according to claim 10 is characterized in that one or more cleaving means are arranged between the sector electric field type TOFMS and a device capable of separately measuring kinetic energy.

  (1) According to the first aspect of the present invention, with respect to the ions emitted from the outlet of the potential lift whose potential can be arbitrarily changed, the ions are made to flow by the reacceleration electrode configured to have the same potential as the sector electric field inlet shunt. By reacceleration, the cleaved ions can pass through the electric field without changing the voltage of the electric field. As a result, it is possible to pass product ions generated in a specific splitting path without changing the voltage of the electric sector.

  (2) According to the invention described in claim 2, by providing one or more ion cleaving means in front of one or more potential lifts, the number of ion cleaving is increased and the structure of the substance is analyzed in more detail. can do.

(3) According to the invention described in claim 3, the structure of the substance can be analyzed in more detail by changing the structure of the cleavage means.
(4) According to the invention described in claim 4, the structure of the substance can be analyzed in more detail by combining a time-of-flight mass spectrometer and another mass spectrometer.

(5) According to the invention described in claim 5, a reflected electric field type mass spectrometer can be used as the another mass spectrometer.
(6) According to invention of Claim 6, a magnetic field type | mold mass spectrometer can be used as said another mass spectrometer.

(7) According to the seventh aspect of the invention, the structure of the substance can be analyzed in more detail by providing one or more cleavage means between two mass spectrometers.
(8) According to the invention described in claim 8, the path of cleavage can be grasped by separately measuring kinetic energy.

(9) According to invention of Claim 9, a sector electric field can be used as said energy separation means.
(10) According to the invention described in claim 10, by providing one or more cleaving means between the electric sector type TOFMS and the apparatus capable of separately measuring kinetic energy, further cleaving is promoted, and the structure of the substance is further detailed. Can be analyzed.

In the present invention, a potential lift is arranged in a circular orbit so that product ions generated in a specific splitting path can pass through without changing the voltage of a sector electric field. When this method is used, it is not necessary to switch the reflected electric field when combined with a sector electric field type TOFMS and a reflected electric field type TOFMS. Therefore, MS ⁿ measurement can be easily performed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention. The same components as those in FIG. 11 are denoted by the same reference numerals. In the figure, 1 is an ion source, 2 is a first collision chamber (collision chamber 1), 3 is a sector (fan-shaped) electric field, 4 is an ion gate, 5 is a second collision chamber (collision chamber 2), and 6 is a reflect. Ron, 7 is a detector.

  Reference numeral 10 denotes a box (potential lift) which is arranged in front of a sector electric field (sector electric field) constituting the sector electric field type TOFMS, the potential of which can be arbitrarily changed (potential lift). There is provided a potential changing means (not shown) capable of changing the potential while passing through. Reference numeral 11 denotes a reacceleration electrode having the same potential as that of the entrance shunt of the sector electric field 3 and provided between the outlet of the potential lift 10 and the entrance shunt of the sector electric field 3.

  FIG. 2 is a schematic diagram of a potential lift, a reacceleration electrode, and a sector electric field. In the figure, 10 is a potential lift, 11 is a reacceleration electrode, 3a is a sector electric field shunt, and 3b is a sector electric field electrode. The operation of the apparatus configured as described above will be described as follows.

Precursor ions generated in the ion source 1 are accelerated by the acceleration voltage V ₀ . At this time, the kinetic energy of the precursor ion (mass M ₀ ) is E ₀ = eV ₀ . When observing precursor ions, the sector electric field 3 is set so that ions of kinetic energy E ₀ can pass through. The voltage of the reflectron 6 is optimized so that ions of energy E ₀ are focused on time. The potential lift 10 and the reacceleration electrode 11 are set to the same potential as the free space. And the inside of the collision chambers 1 and 2 is exhausted.

When observing product ions, collision gas is introduced into the collision chambers 1 and 2. The precursor ions enter the collision chamber 1 and are cleaved by colliding with the gas in the collision chamber 1. By this cleavage, the precursor ion is split into product ions 1m ₁ (hereinafter, _n of the product ions nm n is the number of times of cleavage, and _mn is the path number of the n-th cleavage) and a neutral product. Among these, since the neutral product is not subjected to the electric field, it cannot pass through the sector electric field 3.

Here, if the mass of the product ion (product ion 12 in this case) to be selected is M ₁ , the kinetic energy E ₁ of the product ion 12 is E ₁ = eV ₁ = E ₀ × (M ₁ / M ₀ )
It becomes. Since the energy has changed, the sector electric field 3 cannot be passed as it is.

Therefore, the potential of the potential lift 10 is increased by (V ₀ −V ₁ ) while the product ions 12 pass through the potential lift 10. This operation is performed by potential changing means (not shown). The product ions that have passed through the potential lift 10 are accelerated by the potential difference (V ₀ −V ₁ ) between the exit end face grid electrode of the potential lift 10 and the reacceleration electrode 11 and become kinetic energy E ₀ . Therefore, the voltage of the sector electric field 3 can be passed without changing.

  Further, most of the kinetic energy of the product ions generated by other splitting paths is larger or smaller than that capable of passing through the sector electric field 3, so that it cannot pass through the sector electric field 3.

  In the case of this method, as long as the mass ratio of the precursor ion to the product ion is the same, the product ion can pass from other precursor ions. Further, since the sector electric field 3 has a range of kinetic energy that can be passed, there is a possibility that other than the product ions to be selected may pass. In order to eliminate these ions, an ion gate 4 is provided. When the ion gate 4 is off, the ions can travel straight, and when the ion gate 4 is on, the ions are deflected to deflect the ions. Then, the ion gate 4 is turned off only when the product ions 12 pass, and the others are turned on.

Product ions 12 are introduced into the collision chamber 2 after passing through the ion gate 4. The selected product ions are cleaved by the collision with the gas in the collision chamber 2. All 2m _{2 of the} produced product ions are subjected to mass measurement by a reflected electric field type TOFMS. Specifically, the ions reflected from the reflectron 6 are detected by the detector 7. At this time, since the kinetic energy of the product ion 12 is E ₀ , there is no need to switch the reflected electric field voltage. This enables MS ³ measurement.

  As described above, according to this embodiment, for re-acceleration configured to have the same potential as that of the electric field entrance shunt 3a with respect to ions emitted from the exit of the potential lift whose potential can be arbitrarily changed. By reaccelerating the ions by the electrode 11, the cleaved ions can pass through the electric sector 3 without changing the voltage of the electric sector 3. As a result, it is possible to pass product ions generated in a specific splitting path without changing the voltage of the electric sector.

  Further, by providing one or more ion cleavage means (collision chamber) in front of one or more potential lifts, it is possible to increase the number of ion cleavage times and analyze the structure of the substance in more detail.

Further, by making the structure of each cleavage means different, cleavage can be caused and the structure of the substance can be analyzed in more detail.
Further, by combining a time-of-flight mass spectrometer and another mass spectrometer, the structure of the substance can be analyzed in more detail.

In this case, a reflection electric field type mass spectrometer can be used as the other mass spectrometer.
In addition, a magnetic field type mass spectrometer can be used as the other mass spectrometer.

Moreover, the structure of a substance can be analyzed in more detail by providing one or more cleavage means between two mass spectrometers.
FIG. 3 is a block diagram showing a second embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals. In this embodiment, ions circulate in four sector electric fields to increase the flight distance. The ions that have circulated as many times as necessary are introduced into the ion gate, then enter the collision chamber, where they are cleaved, reflected by the reflectron, and then guided to the detector.

  In FIG. 3, 1 is an ion gun, 3A is a sector electric field 1 for passing ions emitted from the ion source 1, and 3B is a sector electric field 2 for passing ions that have passed through a sector electric field (fan electric field) 1, and 2 is a sector electric field. Collision chambers 1 and 10 into which ions that have passed through 2 are introduced are potential lifts into which ions emitted from the collision chamber 1 are introduced, 11 is a reacceleration electrode that accelerates ions that have passed through the potential lift 10, and 3C is This is a sector electric field 3 through which ions accelerated by the reacceleration electrode 11 pass.

  3D is a sector electric field 4 that allows ions that have passed through the sector electric field 3 to pass therethrough. 4 is an ion gate that receives ions that have passed through the sector electric field 4, 5 is a collision chamber 2 in which ions that have passed through the ion gate 4 are introduced, 6 is a reflectron in which ions that have passed through the collision chamber 2 are introduced, and 7 is It is a detector that guides ions reflected by the reflectron 6. The operation of the apparatus configured as described above will be described as follows.

Precursor ions generated by the ion source 1 are introduced into the same orbital TOFMS and circulate. At the time of introduction, the voltage of the sector electric field 4 is turned off, and the ion is turned on until the ions reach the sector electric field 4 after one round. When accelerating at the acceleration voltage V ₀ in the ion source 1, the kinetic energy E ₀ of the precursor ion (mass M ₀ ) is E ₀ = eV ₀ . Sector electric fields 1 to 4 are set so that ions having a kinetic energy of kinetic energy E ₀ can pass through. The potential lift 10 and the reacceleration electrode 11 are set to the same potential as the free space. The collision chambers 1 and 2 are exhausted.

The number of times necessary for selection of precursor ions (N ₁ times: N ₁ > 0) is circulated. After the precursor ion to be selected passes through the sector electric field 2 in the N _1st round, the collision chamber 1 is filled with gas by the next round. Precursor ions that have passed through the sector electric field 2 on the (N ₁ +1) circumference are cleaved by colliding with the gas in the collision chamber 1. By this cleavage, the precursor ion is split into a product ion 1m ₁ and a neutral product. Neutral products are not subject to electric field forces and cannot pass through the sector electric field 3.

If the mass of the product ion to be selected (product ion 12 in this case) is M ₁ , the kinetic energy E ₁ of the product ion 12 is E ₁ = eV ₁ = E ₀ × (M ₁ / M ₀ )
It becomes. If you fly as it is, you cannot pass through the sector electric field 3.

Therefore, while the product ions pass through the potential lift 10, the potential of the potential lift 10 is raised by (V ₀ −V ₁ ) by a potential changing means (not shown). The product ions that have passed through the potential lift 10 are accelerated by the potential (V ₀ -V ₁ ) between the potential lift 10 outlet end face grid electrode and the reacceleration electrode 11 and become kinetic energy E ₀ .

  Therefore, the voltage of the sector electric field 3 can be passed without changing. Further, most of the kinetic energy of product ions generated by other splitting paths is larger or smaller than that capable of passing through the sector electric field 3, so that it cannot pass through the sector electric field 3. After the product ions pass through the reacceleration electrode 11, the potential of the potential lift 10 is returned to the free space potential, and the gas in the collision chamber 1 is exhausted.

Since the sector electric fields 1 to 4 have a range of kinetic energy that can be passed, there is a possibility that other than the product ions to be selected pass through. The product ions required for selecting them are circulated (N ₂ times: N ₂ > 0). After passing through the sector electric field 1 in the (N ₁ + N ₂ ) cycle, the voltage of the sector electric field 1 is turned off. In the (N ₁ + N ₂ + N ₃ ) round, the product ions 12 go straight through the sector electric field 1 and pass through the sector electric field type TOFMS.

After passing through the sector electric field type TOFMS, the product ions 12 are selected by the ion gate 4. After passing through the ion gate 4, the product ions 12 are introduced into the collision chamber 2. Product ions 12 selected by collision with the gas introduced into the collision chamber 2 are cleaved. Then, the mass of all the generated product ions 2 m ₂ is measured by the reflectron 6. That is, the ions that have passed through the reflectron 6 are detected by the detector 7. Thereby, MS ³ measurement is possible.

  As described above, according to this embodiment, it is possible to perform accurate mass analysis by using the four sector electric fields to circulate the product ions a plurality of times to increase the flight distance. That is, for ions emitted from the outlet of the potential lift whose potential can be arbitrarily changed, the ions are reaccelerated by the reacceleration electrode 11 configured to have the same potential as the electric field entrance shunt 3a, so that the cleaved ions Can pass through the sector electric field 3 without changing the voltage of the sector electric field 3. As a result, it is possible to pass product ions generated in a specific splitting path without changing the voltage of the electric sector.

  According to the present invention, it is possible to combine a time-of-flight mass spectrometer and a device capable of separately measuring kinetic energy. Thereby, the path | route of cleavage can be grasped | ascertained. In this case, a sector electric field can be used as the energy separation device. Further, according to the present invention, by providing one or more cleavage means between the electric field type TOFMS and the apparatus capable of separately measuring kinetic energy, further cleavage can be promoted and the structure of the substance can be analyzed in more detail. it can.

FIG. 4 is a block diagram showing a third embodiment of the present invention. The same components as those in FIG. 3 are denoted by the same reference numerals. In this embodiment, MS ⁿ (n> 4) measurement is performed by the same orbital TOFMS. Each component itself is the same as the embodiment shown in FIG. Only the differences will be described. 4a is a first ion gate disposed between the sector electric field (fan electric field) 4 and the sector electric field 1, and 4b is a second ion gate disposed between the sector electric field 1 and the collision chamber 2. The operation of the apparatus configured as described above will be described as follows.

Precursor ions generated by the ion source 1 are introduced into the same orbital TOFMS and circulate. At the time of introduction, the voltage of the sector electric field 4 is turned off, and the ion is turned on by one turn and before reaching the sector electric field 4. When the ion source 1 is accelerated at the acceleration voltage V ₀ , the kinetic energy E ₀ of the precursor ion (mass M ₀ ) is E ₀ = eV ₀ . The sector electric fields 1 to 4 of the multi-circular TOFMS are set so that ions having kinetic energy of E ₀ can pass through. Then, the ions necessary for selection of the precursor ions (N ₁ times: N ₁ > 0) are circulated.

After the precursor ion to be selected passes through the sector electric field 3 of the N _1st round, the collision chamber 1 is filled with gas by the next round. Precursor ions that have passed through the sector electric field 3 on the (N ₁ +1) circumference are cleaved by colliding with the gas in the collision chamber 1. The precursor ions are split into product ions 1m ₁ and neutral products by cleavage. Neutral products are not subject to electric field forces and cannot pass through the sector electric field 3.

If the mass of the product ion to be selected (product ion 12 in this case) is M ₁ , the kinetic energy E ₁ of the product ion 12 is
E ₁ = eV ₁ = E ₀ × (M ₁ / M ₀ )
It becomes. If you fly as it is, you cannot pass through the sector electric field 3. Therefore, while the product ions pass through the potential lift 10, the potential of the potential lift 10 is changed by (V ₀ −V ₁ ) by a potential changing means (not shown). Product ions that have passed through the potential lift 10 are re-accelerated by the potential (V ₀ -V ₁ ) between the potential lift exit end face grid electrode and the re-acceleration electrode 11 to become kinetic energy E ₀ .

  Therefore, ions can be passed without changing the voltage of the sector electric field 3. In addition, other product ions cannot pass through the sector electric field 3 because the kinetic energy is larger or smaller than that capable of passing through the sector electric field. After the product ions 12 pass through the reacceleration electrode 11, the potential of the potential lift 10 is returned to the orbit center potential, and the gas in the collision chamber 1 is exhausted.

Next, the product ions 12 are further cleaved. Since the sector electric fields 1 to 4 have a range of kinetic energy that can be passed through, the sector electric fields 1 to 4 may pass through other than the product ions to be selected. However, since they all have different flight times, the number of lap product ions required to select them is circulated (N ₃ times: N ₃ > 0). After the product ions 12 have passed through the sector electric field 3 on the (N ₁ + N ₂ +1) th round, the collision chamber 1 is filled with gas by the next round.

Product ions 12 are selected by the ion gate 1 arranged between arbitrary locations of the same orbital TOFMS (between the sector electric fields 4 and 1 in this embodiment). On the (N ₁ + N ₂ +2) circumference, the precursor ions that have passed through the sector electric field 3 are cleaved by colliding with the gas in the collision chamber 1. The precursor ions are split into product ions 2 m ₂ and neutral products by cleavage. A neutral product cannot pass through the sector electric field 3 because it does not receive the force of the electric field.

Next, when the mass of the selected desired product ions (in this case product ions 22) and M _2, the kinetic energy E ₂ of the product ions 22,
E ₂ = eV ₂ = E ₀ × (M ₂ / M ₁ )
It becomes. If you fly as it is, you cannot pass through the sector electric field 3.

Therefore, while the product ions 22 are passing through the potential lift 10, the potential of the potential lift 10 is raised by (V ₀ −V ₂ ) by a potential changing means (not shown). The product ions that have passed through the potential lift 10 are accelerated by the potential (V ₀ -V ₂ ) between the exit end face grid electrode of the potential lift 10 and the reacceleration electrode 11 and become kinetic energy E ₀ . Therefore, ions can be passed without changing the voltage of the sector electric field 3. In addition, most other product ions cannot pass through the sector electric field 3 because the kinetic energy is larger or smaller than that which can pass through the sector electric field.

By the time the product ions 22 reach the sector electric field 1, the voltage of the sector electric field 1 is turned off. The product ions 22 turn off the voltage of the sector electric field 1 before reaching the sector electric field 1. As a result, the product ions 22 travel straight through the sector electric field 1 and fly toward the collision chamber 2. Product ions 22 are selected by the ion gate 2 disposed between the same orbital type TOFMS and the reflected electric field type TOFMS. Product ions 22 selected by collision with the gas introduced into the collision chamber 2 are cleaved. All the generated product ions are subjected to mass measurement by the reflectron 6. That is, the ions that have passed through are guided to the detector 7, whereby the MS ⁴ can be measured. Further, MS ⁿ (n> 5) is possible by repeating the sequence sequentially. The effect of the third embodiment shown in FIG. 4 is the same as that of the second embodiment shown in FIG.

  FIG. 5 is a block diagram showing a fourth embodiment of the present invention. The same components as those in FIG. 4 are denoted by the same reference numerals. In this embodiment, four sector electric fields (fan-shaped electric fields) are arranged in a spiral shape, and ions circulate in a spiral shape to increase the flight time. In the figure, 1 is an ion gun, 3A is a sector electric field 1, 3B is a sector electric field 2, 3C is a sector electric field 3, and 3D is a sector electric field 4. 2 is a collision chamber 1, 10 is a potential lift, 11 is a reacceleration electrode, 4 is an ion gate, 5 is a collision chamber 2, 6 is a reflectron, and 7 is a detector.

  6 is a view of FIG. 5 viewed from the A side, and FIG. 7 is a view of FIG. 5 viewed from the B side. In the case of a spiral trajectory, all trajectories are different and the number of laps is constant depending on the device. Here, the sector electric field 2 on the fifth turn and the collision chamber 1 and the potential lift 10 disposed between the sector electric field 3 are shown, but the present invention is not limited to this. The operation of the apparatus configured as described above will be described as follows.

Precursor ions generated in the ion source 1 are introduced into a spiral orbital TOFMS and circulate. When the ion source 1 is accelerated at the acceleration voltage V ₁ , the kinetic energy E ₀ of the precursor ion (mass M ₀ ) is E ₀ = eV ₀ . The sector electric fields 1 to 4 are set so that ions having E ₀ kinetic energy can pass through. Further, the potential lift 10 and the reacceleration electrode 11 are initially set to the same potential as the free space. Further, the collision chambers 1 and 2 are filled with gas in advance.

The precursor ions that have passed through the fifth round sector electric field 2 are cleaved by colliding with the gas in the collision chamber 1. The precursor ions are split into product ions 1m ₁ and neutral products by cleavage. Neutral products are not subject to the electric field and cannot pass through the sector electric field 3.

If the mass of the product ion to be selected (product ion 12 in this case) is M ₁ , the kinetic energy E ₁ of this product ion 12 is E ₁ = eV ₁ = E ₀ × (M ₁ / M ₀ )
It becomes. Product ions cannot pass through the sector electric field 3 because the energy changes when flying as it is.

Therefore, while the product ions pass through the potential lift 10, the potential of the potential lift 10 is raised by (V ₀ −V ₁ ) by a potential changing means (not shown). Product ions that have passed through the potential lift 10 are accelerated by the potential (V ₀ -V ₁ ) between the potential lift 10 outlet end face grid electrode and the reacceleration electrode, and become kinetic energy E ₀ . Therefore, the product ions can be passed without changing the voltage of the sector electric field 3. In addition, other product ions cannot pass through the sector electric field 3 because the kinetic energy is larger or smaller than that capable of passing through the sector electric field.

Since the sector electric fields 1 to 4 have a range of kinetic energy that can be passed, there is a possibility that other than the product ions to be selected pass through. Therefore, the product ion 12 that has passed through the spiral orbit type TOFMS is selected by the ion gate 4. Product ions 12 are introduced into the collision chamber 2 and cleaved by collision with gas. All the generated product ions are reflected by the reflectron 6 and guided to the detector 7. Thereby, MS ³ measurement is possible. The effect of the embodiment shown in FIG. 5 is the same as that of the embodiment shown in FIGS.

In the embodiment described above, MS ³ has been described. However, if n sets of collision chambers, potential lifts, and reacceleration electrodes are arranged between the electric fields of the spiral orbital TOFMS, MS ^{n + 2} measurement can be performed. .

As described above, according to the present invention, by incorporating a plurality of sets of (cleavage means + potential lift + reacceleration electrode) in a sector electric field (sector electric field) type TOFMS, a sector electric field and a reflected electric field can be reduced. Product ions can be measured without changing the voltage, and MS ⁿ (n> 0) measurement can be performed by a combination of a sector electric field type TOFMS and a reflected electric field type TOFMS.

It is a block diagram which shows the 1st Example of this invention. It is the schematic of a potential lift, the electrode for reacceleration, and a sector electric field. It is a block diagram which shows the 2nd Example of this invention. It is a block diagram which shows the 3rd Embodiment of this invention. It is a block diagram which shows the 4th Example of this invention. It is the figure which looked at FIG. 5 from the A side. It is the figure which looked at FIG. 5 from the B side. It is explanatory drawing of MS / MS measurement. It is an illustration of MS ³ measurements. It is explanatory drawing of ^MSn measurement. It is a conceptual diagram of the apparatus which combined the sector electric field type | mold TOFMS and the reflected electric field type | mold TOFMS.

Explanation of symbols

1 Ion source 2 Collision chamber 1
3 Sector electric field 4 Ion gate 5 Collision chamber 2
6 Reflectron 7 Detector 10 Potential lift 11 Reacceleration electrode

Claims (10)

A time-of-flight mass spectrometer (TOFMS) with one or more sectoral electric fields,
A box (potential lift) that can be arbitrarily changed in potential, arranged in front of one or more sector electric fields constituting the sector electric field type TOFMS;
A potential changing means capable of changing the potential while the target ions pass through the potential lift;
A reacceleration electrode having the same potential as the electric field entrance shunt is disposed between the potential lift exit and the electric field entrance shunt, and ions are reaccelerated by a potential difference between the potential lift exit and the reacceleration electrode. A time-of-flight mass spectrometer.   2. The time-of-flight mass spectrometer according to claim 1, wherein one or more ion cleavage means are arranged in front of the one or more potential lifts.   The time-of-flight mass spectrometer according to claim 2, wherein the plurality of cleavage means have different configurations.   The time-of-flight mass spectrometer according to any one of claims 1 to 3, wherein the time-of-flight mass spectrometer and another mass spectrometer are combined.   5. The time-of-flight mass spectrometer according to claim 4, wherein the other mass spectrometer is a TOFMS having a reflected electric field.   5. The time-of-flight mass spectrometer according to claim 4, wherein the other mass spectrometer is a magnetic field type mass spectrometer.   The time-of-flight mass spectrometer according to any one of claims 4 to 6, wherein one or more cleaving means are disposed between the two mass spectrometers.   The time-of-flight mass spectrometer according to any one of claims 1 to 3, wherein the time-of-flight mass spectrometer and a device capable of separately measuring kinetic energy are combined.   8. The time-of-flight mass spectrometer according to claim 7, wherein the device capable of separately measuring the kinetic energy is a sector electric field.   The time-of-flight mass spectrometer according to claim 8 or 9, wherein one or more cleaving means are arranged between the sector electric field type TOFMS and a device capable of separately measuring kinetic energy.

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