JPH041460B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention comprises a first magnetic field, an electric field, and a second magnetic field, and uses a double-focusing mass spectrometer in the first stage or a double-focusing mass spectrometer in the second stage. The present invention relates to a mass spectrometer that can be configured as a tandem mass spectrometer used as an analyzer.

[Conventional technology]

Generally, in a fan-shaped magnetic field type mass spectrometer,
An analysis sample is ionized by an ion source and introduced through a source slit, and ion beams of the same mass are double focused onto a collector slit using an electric field and a magnetic field for detection and analysis. If the target to be analyzed is a mixture, multiple types of ions will be mixed in the ion peak detected by the collector slit.
A problem arises in that peaks cannot be identified. In such cases, a tandem mass spectrometer consisting of two mass spectrometers connected in series is used to select an ion (precursor ion, parent ion) with a certain peak in the previous stage mass spectrometer, and then The ions (daughter ions) that are cleaved in the collision chamber are analyzed using a subsequent mass spectrometer (MS/MS mass spectrometry; Multi-Stage Mass Spectrometry).
Spectrometry) may be performed.

Assuming that the magnetic field is B, the electric field is E, and the quadrupole mass is Q, there are conventional types of MS/MS combinations.
There are BE, EBE, EBQQ, BEQQ, BEB, EBEB, etc. Of these, FIG. 2 shows a conventional example of a BEB type MS/MS device (tandem type mass spectrometer). Although this MS/MS device is not often seen as a conventional example, it generally adds a single magnetic field B ₂ to the rear of a double convergence mass spectrometer using an inverted optical system B ₁ E, as shown in Figure 2. This has the advantage that it can be used as a B ₁ EB ₂ type. There are the following three methods for use in this case.

It is used as a single mass spectrometer with dual focus consisting of a first magnetic field _B1 and an electric field E.

A first collision chamber CC1 is provided between the first magnetic field _B1 and _the electric field E. a mass spectrometer, and the fragmentation ions from the first mass spectrometer are analyzed by a second mass spectrometer.

A second collision chamber CC2 is provided between the electric field E and the second magnetic field _B2 , and the first mass spectrometer double-focused by the first magnetic field _B1 and the electric field E, and the second magnetic field
B ₂ is a second mass spectrometer, and the fragmentation ions from the first mass spectrometer are analyzed by the second mass spectrometer.

In the BE type MS/MS equipment, the first and second
Since the mass spectrometer uses a single field, its performance is inferior to that of double focusing, with a maximum resolution of about 5000 in a magnetic field, and a resolution of 100 to 200 when analyzing daughter ions in an electric field.
The resolution is approximately On the other hand, in the above case, the second doubly convergent mass spectrometer has a resolution of tens of thousands, which can increase the resolution of daughter ions, and in the above case, the doubly convergent first mass spectrometer has a resolution of tens of thousands. The resolution is close to 10,000,000, and the resolution of parent ions can be improved.

[Problem that the invention seeks to solve]

By the way, in the BEB type device as described above, basic performance such as resolution and passage rate must be guaranteed for the above three methods. However, the first
The arrangement of the first magnetic field B _{1 ,} the electric field E, and the slits S ₁ and S ₃ has been determined for the method of using the magnetic field B 1 and the electric field E as a single mass spectrometer.
Therefore, in general, among the ions emitted from the ion source, the component in the direction perpendicular to the drawing is converged to some extent near the slit _S3 . Ions emitted from this slit _S3 tend to spread in the vertical direction after ejection, making it difficult for them to pass through the narrow gap of the second magnetic field _B2 . The ions emitted from the second magnetic field _B2 then spread further vertically and form a slit.
Reach S ₄ . The ion beam spread out in this manner cannot be detected because the detection capability of the detector D in the vertical direction behind the slit _S4 is limited. In this way, in the past, it was considered impossible to simultaneously satisfy the basic performance of . . . , and the emphasis was placed on the .

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a mass spectrometer capable of improving convergence in a vertical plane and setting correct ion trajectories.

[Means for solving problems]

To this end, the mass spectrometer of the present invention includes a first magnetic field generating means, an electric field generating means, and a second magnetic field generating means, and the front stage is a double convergence mass spectrometer, or the rear stage is a double convergence mass spectrometer. In a mass spectrometer that can now be configured as a tandem mass spectrometer, a slit and an electrostatic quadrupole are provided between a collision chamber arranged behind the electric field generating means and the second magnetic field generating means. It is characterized in that the lens is arranged and the voltage applied to the electrostatic quadrupole lens can be adjusted.

[Effect]

In the mass spectrometer of the present invention, the slit and the electrostatic quadrupole lens are arranged between the collision chamber and the second magnetic field, so the first stage is doubly focused by the first magnetic field, the electric field, and the second magnetic field. The voltage applied to the electrostatic quadrupole lens is adjusted depending on the usage configuration, whether the mass spectrometer is a mass spectrometer that performs double convergence or a mass spectrometer that converges in the second stage to improve convergence and correct ion trajectories. can be set.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining one embodiment of the mass spectrometer according to the present invention, where B ₁ and B ₂ are magnetic fields, and E
is an electric field, CC1 and CC2 are collision chambers, S ₁ to _{S 5} are slits, Q is a Q pole lens, SW is a voltage switching section, I is an ion source, and D is a detector.

The mass spectrometer according to the present invention has a slit _S5 and a Q-pole lens (Quadrupole lens) as shown in FIG. 1 between the collision chamber CC2 and the magnetic field _B2 in the conventional mass spectrometer shown in FIG. An electrostatic quadrupole lens) Q is arranged, and a voltage switching section SW of the Q pole lens is further provided so that the convergence of the Q pole lens Q can be switched between two different modes.

Figure 1a shows how the first magnetic field B ₁ is applied to the first mass spectrometer MS
1. The second mass spectrometer MS2 is doubly focused by the second magnetic field _B2 of the electric field E, and the first mass spectrometer
The dissociation ions from MS1 are transferred to the second mass spectrometer MS.
An example of the case (the above-mentioned usage method) is shown below. In this case, the collision chamber CC
Since the entire amount of ions is passed through without using the slit S 2 or the slit S ₅ , the ions emitted from the slit S ₃ tend to spread in the vertical direction after being emitted, as described above. Therefore, a Q-pole lens Q is used to perform vertical convergence. That is, the first magnetic field B ₁ and the electric field E
The arrangement of the first magnetic field B ₁ , electric field E, and slits S ₁ and S ₂ is determined for use as a single mass spectrometer by The ingredients are Slit S ₃
It converges near . Therefore, the ions emitted from the slit _S3 tend to spread in the vertical direction after being emitted, making it difficult for them to pass through the narrow gap of the second magnetic field _B2 . Moreover, since the ions emitted by the second magnetic field _B2 further spread in the vertical direction and reach the slit _S4 , the detector D behind the slit _S4 has a limit in its detection ability in the vertical direction. Beam cannot be detected. Q pole lens Q is
In order to overcome this problem, vertical convergence is performed between the slit _S3 and the second magnetic field _B2 . Note that the electric field E and the second magnetic field
Double focusing in the optical system B ₂ can be completely obtained by appropriately selecting the distances l ₁ and l ₂ shown.

In addition, Fig. 1b shows an example of the case where the mass spectrometer MS1' is used as a single mass spectrometer that is doubly focused by the first magnetic field _B1 and the electric field (the above-mentioned method of use), or when a second magnetic field is added at the subsequent stage. B ₂ into the second mass spectrometer
This shows an example in which, in addition to MS2', the dissociation ions from the first mass spectrometer MS1' are analyzed by the second mass spectrometer MS2'.

First, when the former is used as a single mass spectrometer, there is no difference from the prior art. For this purpose, a first magnetic field B ₁ , an electric field E, a slit S ₁ ,
The placement of S ₃ is determined.

On the other hand, in the latter case, the ions fragmented in the collision chamber CC2 are analyzed using the second magnetic field _B2 , so the important point in this case is that the ions are analyzed in order to improve the resolution of the second magnetic field _B2 . The two points are that the trajectory of the fragmented ions must be limited by a slit, and that a high voltage may be applied to the collision chamber CC2 for the same purpose. In this case, the collision chamber CC
In order to prevent disturbances in the convergence of ions that act as a lens in the second analyzer, it is necessary to arrange a slit _S5 for the second analyzer in addition to the slit _S3 . Therefore, if the same voltage as in Figure 1a is applied to the Q pole lens Q, the ions exiting the slit _S5 will
It no longer forms an image on S ₄ . Therefore, in this case, the ions emitted from the slit _S5 are imaged onto the slit _S4 by applying a voltage different from that shown in FIG. 1a to the Q pole lens.

Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, the present invention provides an optical system for the first magnetic field _B1 and the electric field E.
It can also be applied when using a QQHQC optical system (for example, Japanese Patent Application No. 58-33168). In addition, in the collision chamber CC2,
It can also be applied when a lens for forming an image on the slit _S5 is included, and the portion of the collision chamber CC2 in FIG. 1b shows an example in which this is applied.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a mass spectrometry system that includes a first magnetic field, an electric field, and a second magnetic field, and a collision chamber is provided between the electric field and the second magnetic field, Since a Q-pole lens is used between the collision chamber and the second magnetic field, convergence in the vertical plane is improved. Further, by providing a slit between the collision chamber and the Q-pole lens, the trajectory of the dissociated ions can be correctly regulated, and even when a voltage is applied to the collision chamber, the correct ion trajectory can be set. Furthermore, when the voltage applied to the G pole lens is used as an optical system using an electric field and a second magnetic field, and when the voltage is applied to the G pole lens,
By switching between the case of using the magnetic field as an optical system and the case of using it as an optical system for a magnetic field, it is possible to form an image correctly using both optical systems.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of one embodiment of a mass spectrometry system according to the present invention, and FIG. 2 is a diagram showing a conventional example of an EBE type MS/MS apparatus. B ₁ and B ₂ ...Magnetic field, E...Electric field, CC1 and CC2...
... Collision chamber, S ₁ to S ₅ ... Slit, Q ... Q pole lens, SW ... Power switching section, I ... Ion source, D ... Detector.

Claims (1)

[Claims] 1. A tandem mass spectrometer comprising a first magnetic field generating means, an electric field generating means, and a second magnetic field generating means, and configured as a tandem mass spectrometer in which the first stage is a double convergence mass spectrometer or the second stage is a double convergence mass spectrometer. In the mass spectrometer that has become possible, a slit and an electrostatic quadrupole lens are arranged between the collision chamber arranged behind the electric field generating means and the second magnetic field generating means, and the electrostatic A mass spectrometer characterized by being configured to be able to adjust the voltage applied to a quadrupole lens.