JP4229732B2 - Time-of-flight mass spectrometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a time-of-flight mass spectrometer having an orbit formed by a plurality of electric sector fields.
[0002]
[Prior art]
In the field of mass spectrometry using a magnetic mass spectrometer or a quadrupole mass spectrometer, connect multiple mass spectrometers in series and provide a dissociation chamber at the connection location. The mass-separated specific ions are introduced into the dissociation chamber, and the parent ions are dissociated into daughter ions by colliding with low-pressure gas molecules or irradiating light in the dissociation chamber. Tandem mass spectrometry, in which mass spectrometry is performed using a mass spectrometer, is widely performed.
[0003]
On the other hand, in the field of mass spectrometry using a time-of-flight mass spectrometer, a circulation type time-of-flight mass spectrometer has been proposed which aims to improve the resolution by increasing the flight distance.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-135060 [Non-Patent Document 1]
M. Toyoda et al., J. Mass Spectom., Vol.35 (2000), pp.163-167.
[Non-Patent Document 2]
Toyoda Gijo et al., J. Mass Spectrom. Soc. Jpn., Vol.48 (2000), pp.312-317.
[0005]
[Problems to be solved by the invention]
By the way, in the conventional tandem mass spectrometry using a magnetic field type mass spectrometer or a quadrupole mass spectrometer, there is an upper limit in the mass range of parent ions that can be analyzed, and the resolution of ion selection is low. There was a problem that analysis with high accuracy was difficult.
[0006]
In addition, in conventional tandem mass spectrometry using a magnetic mass spectrometer or quadrupole mass spectrometer, all ions except the parent ion selected by the first mass spectrometer are discarded, and a small sample The tandem mass spectrometry in the above method has a problem that it is difficult in terms of sensitivity.
[0007]
In view of the above-described points, the object of the present invention is to take advantage of the orbital time-of-flight mass spectrometer, has no upper limit in the mass range of parent ions, has high ion sorting resolution, and has the parent selected first. To provide a time-of-flight mass spectrometer capable of performing tandem mass spectrometry without throwing away ions other than ions.
[0008]
[Means for Solving the Problems]
In order to achieve this object, the time-of-flight mass spectrometer of the present invention is
A first mass analyzing means comprising a circular orbit constituted by a plurality of electric sector electric fields, and separating ions having different masses by repeatedly flying the circular orbit ;
An incident means for implanting ions into the first mass analyzing means ;
An extraction means for extracting ions from the first mass analysis means ;
Dissociation means provided outside the orbit of the orbit in order to dissociate ions extracted from the first mass analysis means via the emission means;
And a second mass analyzing means for performing mass analysis by making ions dissociated by the dissociating means incident .
[0009]
Further, the extraction means is characterized in that only ions having a predetermined mass can be extracted at a predetermined timing while flying around the orbit for other mass ions .
[0010]
Further, the second mass analyzing means is a second time-of-flight mass spectrometer.
[0011]
The second time-of-flight mass spectrometer is
An orbit formed by a plurality of electric sector fields,
An incident means for implanting ions;
And an extraction means for extracting ions.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a time-of-flight mass spectrometer according to the present invention. In the present embodiment, a first orbiting type time-of-flight mass spectrometer having an orbit composed of four electric electric fields 1 to 4 and a second orbit including an orbit composed of four electric electric fields 10 to 13 are used. And a dissociation chamber 9 such as an ion trap is provided at the connection between the two orbital time-of-flight mass spectrometers.
[0014]
FIG. 2 is a diagram for explaining the above embodiment in detail. The closed orbit of the first mass spectrometer is composed of sector electric fields 1, 2, 3, and 4.
[0015]
Ions emitted in a pulse form from the ion source 5 enter the electric sector 2 that is an incident trajectory. At this time, the electric potential of the electrode of the sector electric field 2 is off (zero potential), and the ions are incident on the closed orbit through the incident path such as the incident hole 20 opened in the electrode of the sector electric field 2. . Immediately after this, the electric potential of the electrode of the sector electric field 2 is turned on, and the incident ions start to circulate in the shape of figure 8 on the closed orbit constituted by the sector electric fields 1, 2, 3, and 4. The incident hole 20 and a control circuit (not shown) for controlling the sector electric field 2 to be turned off at the time of ion incidence and turned on after the incidence constitute ion incidence means.
[0016]
When the ions introduced into the closed orbit have completed the required number of laps and the mass separation between the ions is sufficiently performed, the potential of the electrode of the sector electric field 1 is turned off for a predetermined time width at a predetermined timing. (Zero potential) and only target ions (parent ions) are taken out from the closed orbit through the exit path such as the exit hole 21 opened in the sector electric field 1. All the remaining ions continue to circulate in the closed orbit while remaining as they are. The exit hole 21 and a control circuit (not shown) for controlling the sector electric field 1 to be turned off at the timing of taking out the ions constitute ion exit means.
[0017]
The parent ions thus taken out from the first mass spectrometer are captured in a dissociation chamber 9 such as an ion trap, and in the dissociation chamber 9, CID (Collision Induced Dissociation), ECD (Electron Capture Dissociation), PID (Photo Induced) It is dissociated into daughter ions by a known method such as Dissociation) or IRMPD (Infrared Multi-photon Dissociation).
[0018]
FIG. 3 illustrates the continuation of the above embodiment. Daughter ions generated in the dissociation chamber 9 are given predetermined energy in the dissociation chamber 9 at a predetermined timing, and are extracted from the dissociation chamber 9 in pulses. The extracted daughter ions enter the sector electric field 11 which is the incident orbit of the second mass spectrometer. At this time, the electric potential of the electrode of the sector electric field 11 is off (zero potential), and the daughter ions enter the closed orbit through the incident path such as the incident hole 22 opened in the electrode of the sector electric field 11. Is done. Immediately after this, the electric potential of the electrode of the sector electric field 11 is turned on, and the incident daughter ions start to circulate in the shape of figure 8 on the closed orbit formed by the sector electric fields 10, 11, 12, and 13.
[0019]
When the daughter ions introduced into the closed orbit complete the necessary number of laps and the ions are sufficiently separated from each other, the electric potential of the electric field 10 is turned off (zero potential) at a predetermined timing. The daughter ions are emitted from the circular orbit through the exit path such as the exit hole 23 opened in the sector electric field 10 and reach the ion detector 14. Thereby, the mass spectrum of the daughter ion produced | generated from the specific parent ion can be obtained.
[0020]
FIG. 4 shows another embodiment of the time-of-flight mass spectrometer according to the present invention. This embodiment is composed of one orbital time-of-flight mass spectrometer having a circular orbit composed of four sector electric fields 1 to 4, and among the four sector electric fields, in the vicinity of one sector electric field 1. Is provided with a dissociation chamber 9 such as an ion trap.
[0021]
FIG. 5 is a diagram for explaining the above embodiment in detail. The closed orbit of this mass spectrometer is composed of sector electric fields 1, 2, 3, and 4.
[0022]
Ions emitted in a pulse form from the ion source 5 enter the electric sector 2 that is an incident trajectory. At this time, the electric potential of the electrode of the sector electric field 2 is off (zero potential), and ions are incident on the closed orbit through the incident path such as the incident hole 20 opened in the electrode of the sector electric field 2. The Immediately after this, the electric potential of the electrode of the sector electric field 2 is turned on, and the incident ions start to circulate in the shape of figure 8 on the closed orbit constituted by the sector electric fields 1, 2, 3, and 4.
[0023]
When the ions introduced into the closed orbit complete the required number of turns and the ions are sufficiently separated from each other, the electric potential of the electrode of the electric sector 1 is turned off at a predetermined timing for a predetermined time width ( Zero potential), and only target ions (parent ions) are taken out from the closed orbit through the exit path such as the exit hole 21 opened in the sector electric field 1. All the remaining ions continue to circulate in the closed orbit while remaining as they are.
[0024]
The parent ions thus extracted from the mass spectrometer are captured in a dissociation chamber 9 such as an ion trap, and in the dissociation chamber 9, CID (Collision Induced Dissociation), ECD (Electron Capture Dissociation), PID (Photo Induced Dissociation), It is dissociated into daughter ions by a known method such as IRMPD (Infrared Multi-photon Dissociation).
[0025]
FIG. 6 illustrates the continuation of the above embodiment. Daughter ions generated in the dissociation chamber 9 are given predetermined energy in the dissociation chamber 9 at a predetermined timing, and are extracted from the dissociation chamber 9 in pulses. The extracted daughter ions enter the sector electric field 1 that was the exit trajectory of the original mass spectrometer. At this time, the electric potential of the electrode of the sector electric field 1 is off (zero potential), and the daughter ions enter the closed orbit through the incident path such as the incident hole 21 opened in the electrode of the sector electric field 1. Is done. Immediately after this, the electric potential of the electrode of the sector electric field 2 is turned on, and the incident daughter ions pass through the closed orbit formed by the sector electric fields 10, 11, 12, and 13 in the direction opposite to the parent ion. , Begin to circulate in the shape of figure 8.
[0026]
When the daughter ions introduced into the closed orbit complete the necessary number of times in the reverse direction and are sufficiently separated by mass, the potential of the electrode of the electric sector 3 is turned off (zero potential) at a predetermined timing. Daughter ions are emitted from the circular orbit through the exit path such as the exit hole 24 opened in the sector electric field 3 and reach the ion detector 15. Thereby, the mass spectrum of the daughter ion produced | generated from the specific parent ion can be obtained.
[0027]
A modification can be made to the second embodiment in which the mass separation of the parent ion and the daughter ion is performed in the reverse direction using the same mass spectrometer. It uses a technique called SID (Surface Induced Dissociation) that causes the parent ions to collide with a wall made of a special material instead of the dissociation chamber 9 such as an ion trap, and dissociates the parent ions into daughter ions when they bounce off. The same effect is obtained even if the parent ions are dissociated into daughter ions. In that case, the dissociation chamber 9 is unnecessary.
[0028]
Further, when returning the daughter ions from the dissociation chamber 9 to the sector electric field 1, if the daughter ions are returned not in the direction of the sector electric fields 1 to 2 but in the direction of the sector electric fields 1 to 3, the incident daughter ions are converted into the sector electric field. The closed orbit composed of 1, 2, 3, and 4 can be circulated in the same direction as the parent ion. In that case, it is necessary to provide an ion detector 15 ′ capable of detecting daughter ions that have been circulated in the same direction as the parent ions, for example, as indicated by a broken line in FIG. Needless to say, the ion detector 15 ′ can be used for detecting parent ions when tandem mass spectrometry is not performed (when the dissociation chamber 9 is not used).
[0029]
【The invention's effect】
As a result of the present invention, taking advantage of the time-of-flight mass spectrometer having an orbit formed by a plurality of sector electric fields, there is no upper limit in the mass range of the parent ion, the ion selection resolution is high, and the selection is made first. It has become possible to provide a time-of-flight mass spectrometer that can perform tandem mass spectrometry without throwing away ions other than the parent ions.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram showing an embodiment of the present invention.
FIG. 3 is a diagram showing an embodiment of the present invention.
FIG. 4 is a diagram showing another embodiment of the present invention.
FIG. 5 is a diagram showing another embodiment of the present invention.
FIG. 6 is a diagram showing another embodiment of the present invention.
[Explanation of symbols]
1-4 electric sector, 5 ... ion source, 9 ... dissociation chamber, 10-13 ... electric sector, 14 ... ion detector, 15 ... ion detector, 15 ' ... ion detectors, 20-24 ... holes.

Claims (4)

A first mass analyzing means comprising a circular orbit constituted by a plurality of electric sector electric fields, and separating ions having different masses by repeatedly flying the circular orbit ;
An incident means for implanting ions into the first mass analyzing means ;
An extraction means for extracting ions from the first mass analysis means ;
Dissociation means provided outside the orbit of the orbit in order to dissociate ions extracted from the first mass analysis means via the emission means;
A time-of-flight mass spectrometer, comprising: a second mass analyzer that performs mass analysis by injecting ions dissociated by the dissociator. 2. The time-of-flight mass spectrometer according to claim 1, wherein the extraction means can extract only ions having a predetermined mass at a predetermined timing while flying in a circular orbit for other mass ions . The time-of-flight mass spectrometer according to claim 1 or 2, wherein the second mass spectrometer is a second time-of-flight mass spectrometer. The second time-of-flight mass spectrometer is
An orbit formed by a plurality of electric sector fields,
An incident means for implanting ions;
4. A time-of-flight mass spectrometer according to claim 3, further comprising an emission means for extracting ions.

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