JP2007227042A - Spiral orbit type time-of-flight mass spectrometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spiral orbit type TOMFMS which is used as an apparatus performing MS<SP>n</SP>by one spiral orbit type TOMFMS in a compact space, and effectively implement a high level MS<SP>n</SP>to fully use the high resolution and the high mass accuracy inherently provided with the spiral orbit type TOMFMS. <P>SOLUTION: The spiral orbit type TOMFMS includes acceleration and deceleration portions 33 and 34 provided on both ends of the TOFMS to accelerate and decelerate ions and a round-trip means for implementing a TOMFMS mechanism by making the ions to go and return in the TOMFMS space by the acceleration and deceleration portions 33 and 34. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a spiral orbit type time-of-flight mass spectrometer. More specifically, it is used for an organic compound structure analysis method called MS ⁿ in mass spectrometry. In particular, the present invention relates to an apparatus for obtaining structural information of a target ion by selecting a specific target ion, dissociating the ion by CID (collision-induced dissociation), and selecting one of the dissociated ions for mass analysis. Is.

  A time-of-flight mass spectrometer (hereinafter abbreviated as TOFMS) measures the time of flight required to fly a certain distance based on the fact that sample ions accelerated with a constant acceleration energy have a flight speed corresponding to the mass. The mass is obtained. FIG. 3 shows the measurement principle of TOFMS. In the figure, reference numeral 5 denotes a pulse ion source, which includes an ion generator 6 and a pulse voltage generator 7.

  The ions i existing in the electric field are accelerated by the pulse voltage generator 7. Here, the accelerating voltage is a pulse voltage. The acceleration by the acceleration voltage and the time measurement by the ion detector 9 are synchronized. The ion detector 9 starts counting time simultaneously with acceleration by the pulse voltage generator 7. When the ions reach the ion detector 9, the ion detector 9 measures the flight time of the ions i. Generally, this flight time becomes longer as the mass increases. Since ions having a small mass reach the ion detector 9 quickly, the flight time is shortened.

The mass resolution of this TOFMS is T, where the total flight time is T and the peak width is ΔT.
It is represented by T / 2ΔT. That is, if the peak width ΔT is kept constant and the total flight time T can be extended, the mass resolution can be improved. A multi-turn time-of-flight mass spectrometer has been developed to increase the total flight time (see, for example, Non-Patent Document 1). This multi-turn type TOFMS can extend the total flight time T by using four toroidal electric fields in which a plate is combined with a cylindrical electric field, and making an eight-shaped round orbit multiple times.

  However, in the TOFMS that makes multiple rounds of this closed orbit, a so-called “overtaking” problem occurs. Here, “passing” means that light ions having a high speed pass heavy ions having a low speed because ions are traveling around the closed orbit multiple times. For this reason, the basic concept of TOFMS that arrives in order from light ions to the detection surface is not valid.

  Therefore, a helical trajectory TOFMS has been devised to solve such problems. This helical trajectory type TOFMS is characterized in that the start point and end point of a closed trajectory are shifted in a direction perpendicular to the closed trajectory plane. In order to realize this, there are a method of obtaining ions obliquely from the beginning (for example, see Patent Document 1), and a method of shifting the start point and end point of a closed orbit in the vertical direction using a deflector (for example, see Patent Document 2). .

FIG. 4 is a conceptual diagram of a spiral orbit type TOFMS. 10 is a pulse ion source, 16 is a deflector for adjusting the ion trajectory from the pulse ion source 10, and 17 is an electrode arranged on the object as shown in the figure. The electric fields formed by the electrodes 17 are referred to as laminated toroidal electric fields 1 to 4, respectively. A is the starting point and the end point of the circulation part. The electrode 17 has a spiral trajectory in a direction perpendicular to the drawing sheet. A detector 15 detects ions that have passed through the spiral trajectory. In the figure, A is not only the starting point of the circulation part but also the end point of the circulation.
Journal of the Mass Spectrometry Society of Japan Vol. No. 2 (No. 218) 2003 p349-353 JP 2000-243345 A (2nd page, 3rd page, FIG. 1) JP 2003-86129 A (2nd page, 3rd page, FIG. 1)

Conventionally, in the spiral trajectory type TOFMS, ideas and the like for realizing MS ⁿ have been shown, but there has been no use of using one spiral trajectory many times including reverse rotation. In addition, no single acceleration mechanism was used for both purposes.

The present invention has been made in view of such problems, and is used as a device capable of performing MS ⁿ with a single helical trajectory type TOFMS in a compact space. The object is to efficiently realize advanced MS ⁿ that fully utilizes the function of mass accuracy.

(1) The invention according to claim 1 is a helical trajectory type time-of-flight mass spectrometer, an acceleration / deceleration unit provided at both ends of the time-of-flight mass spectrometer and capable of accelerating and decelerating ions; And a reciprocating means for realizing a time-of-flight mass spectrometer mechanism by reciprocating ions in the time-of-flight mass spectrometer space by the acceleration / deceleration unit.
(2) The invention according to claim 2 is characterized in that the spiral orbital time-of-flight mass spectrometer has an intermediate convergence point for each lap, and a detector is provided at the intermediate convergence point at both ends. .
(3) The invention according to claim 3 utilizes the fact that the spiral orbit type time-of-flight mass spectrometer has an intermediate convergence point for each lap, and then enters the intermediate convergence point one round before the detector, In addition, an acceleration / deceleration unit that emits from this is provided, and the sector portion of this portion is used as a switch for switching to either the acceleration / deceleration unit or the detector in accordance with the flight time of the selected ions.
(4) The invention described in claim 4 is characterized in that there is provided means for ejecting the selected ions toward the spiral orbit type time-of-flight mass spectrometer again at an appropriate timing.

(1) According to the first aspect of the invention, by utilizing the acceleration / deceleration unit as an acceleration function or a deceleration function, it is possible to reciprocate in the spiral trajectory and obtain structural information of target ions.
(2) According to the invention described in claim 2, since the detector is provided at the intermediate convergence point at both ends of the spiral trajectory, ions can be obtained using any of the detectors provided at both ends of the spiral trajectory as required. Can be detected.
(3) According to the invention described in claim 3, it is possible to switch, using the sector part, whether the ions that reciprocate on the spiral trajectory reach the acceleration / deceleration part or the detector.
(4) According to the invention described in claim 4, the ions can be reciprocated on the spiral orbit by ejecting the trapped ions again toward the spiral orbital TOFMS.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 30 is an ion source for generating ions, 31 is an ion trap 1 for trapping ions emitted from the ion source 30, and 33 is an ion trap for accelerating ions emitted from the ion trap 1 and from a spiral trajectory. This is an acceleration / deceleration unit 1 that decelerates ions entering one side. The acceleration / deceleration unit 1 is provided one round before the detector 2.

  Reference numeral 20 denotes a helical orbit type TOFMS, which has eight layers of spirals 1 to 8 in the figure. Reference numeral 21 denotes a detector 2 for detecting ions provided at an intermediate convergence point at one end of the spiral trajectory, and reference numeral 22 denotes a detector 1 for detecting ions provided at an intermediate convergence point at the other end of the spiral trajectory. . Reference numeral 23 denotes a sector part 1 and 24 provided in the first layer of the spiral orbit, and reference numeral 24 denotes a sector part 2 provided in the seventh layer of the spiral orbit.

  The sector unit 1 operates as a switch for selecting whether to guide the ions reciprocating in the spiral trajectory to the acceleration / deceleration unit 1 or to the detector 2. On the other hand, the sector unit 2 operates as a switch for selecting whether to guide the ions reciprocating along the spiral trajectory to the acceleration / deceleration unit 2 or to the detector 1. Reference numeral 32 denotes an ion trap 2, and 34 denotes an acceleration / deceleration unit that accelerates or decelerates ions provided one round before the detector 1. The acceleration / deceleration unit 2 and the ion trap 2 are provided on the opposite side of the acceleration / deceleration unit 1 and the ion trap 1 with respect to the spiral trajectory. The operation of the apparatus configured as described above will be described as follows.

Here, the case of 8 rounds will be described as an example.
(Operation as normal TOFMS)
The ions produced by the ion source 30 first enter the ion trap 1. The trapped ions are ejected at an appropriate timing with energy of about 30 eV, and are accelerated to about 10 keV through the acceleration / deceleration unit 1. After that, it passes through the sector part 1 and is driven into the helical part 1 of the helical trajectory type TOFMS. After that, it orbits the spiral trajectory as it is, is detected by the detector 1 in the portion of the spiral 8, and is subjected to high resolution and high accuracy time-of-flight mass analysis. Here, the detector 1 is installed at an intermediate convergence point of the helical trajectory type TOFMS, so that the resolution is optimized.
(Operation of MS / MS as TOFMS)
As a result of the operation as the above-described normal TOFMS, the target ion to be structurally analyzed is specified. The sector part 2 is switched so that the target ions are guided to the acceleration / deceleration part 2 at the time of the flight time passing through the sector part 2 in the portion 7 of the helix through the same process as described above. Here, the sector part 2 is installed one round before the detector 1 and is installed so as to efficiently decelerate from the intermediate convergence point. Here, the ions decelerated to about 30 eV are guided to the ion trap 2. Here, the selected ions are cleaved by CID or the like.

Next, the cleaved ions are ejected from the ion trap 2 with energy of about 30 eV at an appropriate timing, and are accelerated to about 10 keV through the acceleration / deceleration unit 2. Then, it passes through the sector part 2 and is driven into the spiral 7 part of the spiral orbit type TOFMS. And it detects with the detector 2 in the 0 part of a helix, and carries out high resolution and highly accurate time-of-flight mass spectrometry. This enables MS / MS.
(Operation of MS ⁿ as TOFMS)
As a result of the above operation of the MS / MS as TOFMS, if there is an ion to be further cleaved and examined, this ion passes through the sector 1 in the 1 part of the helix through the same process as above. The sector portion 1 is switched so as to be guided to the acceleration / deceleration portion 1 at the timing of the flight time. The ions selected here are decelerated to about 30 eV and guided to the ion trap 1. Here, the selected ions are further cleaved by CID or the like.

Next, the cleaved ions are ejected from the ion trap 1 with energy of about 30 eV at an appropriate timing, and are accelerated to about 10 keV through the acceleration / deceleration unit 1. After that, it passes through the sector part 1 and is driven into the helical part 1 of the helical trajectory type TOFMS. Then, it is detected by the detector 1 in the portion 8 of the helix and subjected to high resolution and high accuracy time-of-flight mass spectrometry. This makes MS ³ possible.

By repeating such an operation, it is possible to operate MS ^{n as} a TOFMS.
As described above, according to the present invention, by using the acceleration / deceleration unit as the acceleration function or the deceleration function, the spiral trajectory can be reciprocated, and the structure information of the target ions can be obtained. In addition, according to the present invention, since the detector is provided at the intermediate convergence point at both ends of the spiral trajectory, ions can be detected using any of the detectors provided at both ends of the spiral trajectory as necessary. It becomes possible.

  In addition, according to the present invention, it is possible to use the sector portion to switch whether the ions that reciprocate on the spiral trajectory reach the acceleration / deceleration portion or the detector. Furthermore, the ions can be reciprocated on the spiral trajectory by firing the trapped ions again toward the spiral trajectory TOFMS.

  The technique of repeatedly using the same trajectory in the opposite direction is not limited to the spiral trajectory described above, but may be possible in, for example, the reflectron type TOFMS shown in FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals. In the figure, 30 is an ion source, 31 is an ion trap 1, 32 is an ion trap 2, 33 is an acceleration / deceleration unit 1, 34 is an acceleration / deceleration unit 2, 37 is an intermediate convergence point 1, 38 in contact with the acceleration / deceleration unit 2, and acceleration It is an intermediate convergence point in contact with the deceleration unit 1.

  In contrast to the case of the helical trajectory type TOFMS for each round of the intermediate convergence point, in the case of the reflectron type TOFMS, it is difficult in terms of installation space to actually arrange the detector at the intermediate convergence point. In addition, the reflectron type intermediate convergence points 37 and 38 have a small mass dispersion, resulting in a very low resolution and a practical difficulty.

It is a block diagram which shows one embodiment of this invention. It is a figure which shows the application to the reflectron type | mold TOFMS of this invention. It is a figure which shows the measurement principle of TOFMS. It is a conceptual diagram of helical trajectory type TOFMS.

Explanation of symbols

20 Spiral orbit type TOFMS
21 Detector 2
22 Detector 1
23 Sector part 1
24 Sector part 2
30 Ion source 31 Ion trap 1
32 Ion trap 2
33 Acceleration / deceleration unit 1
34 Acceleration / deceleration part 2

Claims (4)

In the helical orbit type time-of-flight mass spectrometer, an acceleration / deceleration unit provided at both ends of the time-of-flight mass spectrometer and capable of accelerating and decelerating ions;
Reciprocating means for realizing a time-of-flight mass spectrometer mechanism by reciprocating ions in the time-of-flight mass spectrometer space by the acceleration / deceleration unit;
A spiral orbit type time-of-flight mass spectrometer.   The spiral orbit type time-of-flight type mass spectrometer according to claim 1, wherein the spiral orbit type time-of-flight mass spectrometer has an intermediate convergence point for each lap and the detectors are provided at intermediate convergence points at both ends. Mass spectrometer.   Utilizing the fact that the spiral orbit type time-of-flight mass spectrometer has an intermediate convergence point for each lap, an acceleration / deceleration unit that enters and exits from the intermediate convergence point one lap before the detector is selected and selected. The spiral orbit type time-of-flight mass spectrometer according to claim 1, wherein the sector part of this part is used as a switch for switching to either the acceleration / deceleration part or the detector in accordance with the time of flight of the ions.   4. The spiral orbit type time-of-flight mass spectrometer according to claim 3, further comprising means for launching selected ions again toward the spiral orbit type time-of-flight mass spectrometer at an appropriate timing.

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