MALDI ion source and mass spectrometry device

Abstract

In the MALDI ion source (1), the laser light from the laser light source (2) is reflected by the reflector (5), and then the energy is adjusted in the polarization beam splitter (6). Then, the laser light with the adjusted energy is irradiated toward the sample. In addition, the polarization beam splitter (6) adjusts the energy of the laser light by rotating itself. Therefore, in the MALDI ion source (1), only by providing a rotatable polarization beam splitter (6), it is possible to adjust the energy of the laser light and irradiate the laser light toward the sample.

Description

Technical Field

[0001] The present invention relates to a MALDI ion source for ionizing a sample by MALDI and a mass spectrometer equipped with the MALDI ion source. Background Art

[0002] Conventionally, a MALDI ion source is used to ionize a sample by MALDI. For example, when a MALDI ion source is used in a mass spectrometer, a laser is irradiated onto the sample to ionize the sample. Then, the ionized sample is separated in time according to the mass-to-charge ratio in a mass separation unit and detected sequentially by a detector (for example, refer to Patent Document 1 below).

[0003] In order to create a high-precision spectrum in a mass spectrometer using a MALDI ion source, it is necessary to irradiate a sample with laser light at an appropriate intensity. Therefore, in a mass spectrometer using a MALDI ion source, a mechanism for adjusting the laser light intensity is used.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2011 / 081180 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] As a MALDI ion source provided with a mechanism for adjusting the laser intensity, for example, it is conceivable to use Figure 3 A MALDI ion source 200 is shown.

[0009] Figure 3 The MALDI ion source 200 shown includes a chamber 201, a laser light source 202, and a camera 203. The laser light source 202 and the camera 203 are disposed at a distance from the chamber 201, respectively.

[0010] A window sheet 204 is provided on the peripheral wall of the chamber 201. The camera 203 and the window sheet 204 are arranged at a distance. A dichroic mirror 205 is provided between the camera 203 and the window sheet 204.

[0011] A rotating density filter 206 and a beam expander 207 are provided between the laser light source 202 and the dichroic mirror 205. Specifically, the rotating density filter 206 is provided on the dichroic mirror 205 side, and the beam expander 207 is provided on the laser light source 202 side. The rotating density filter 206 can rotate around the optical axis of the light from the laser light source 202 to the dichroic mirror 205. The rotating density filter 206 transmits light of an amount corresponding to the rotation position. The beam expander 207 is used to expand the diameter of the transmitted laser light.

[0012] The chamber 201 contains a sample placed on a sample disk 210 .

[0013] In the MALDI ion source 200, the laser light emitted from the laser light source 202 passes through the beam expander 207 and then passes through the rotating concentration filter 206. The laser light is reflected by the dichroic mirror 205, passes through the window 204, and enters the chamber 201, thereby irradiating the sample on the sample disk 210. In addition, the light from the sample passes through the window 204 and is received by the camera 203. Then, the irradiation position of the laser light is adjusted based on the imaging result of the camera 203.

[0014] At this time, in the MALDI ion source 200, the light quantity (intensity) of the laser beam irradiated to the sample is adjusted by rotating the rotary concentration filter 206. Therefore, the laser beam is irradiated to the sample at an appropriate intensity.

[0015] In addition, as a MALDI ion source provided with a mechanism for adjusting the laser intensity, for example, Figure 4 The MALDI ion source 300 is shown. Figure 4 In the MALDI ion source 300, Figure 3 The same components of the MALDI ion source 200 are marked with the same reference numerals.

[0016] exist Figure 4 In the MALDI ion source 300 shown, no optical element is provided between the laser light source 202 and the dichroic mirror 205. A wave plate 301 and a polarization beam splitter 302 are provided between the dichroic mirror 205 and the window 204. Specifically, the wave plate 301 is provided on the dichroic mirror 205 side, and the polarization beam splitter 302 is provided on the window 204 side. The wave plate 301 can be rotated around the optical axis of the light from the dichroic mirror 205 to the window 204. The wave plate 301 is used to change the polarization direction of the incident light. The wave plate 301 changes the polarization direction of the light according to the rotation position. The polarization beam splitter 302 allows light of the amount of light corresponding to the polarization direction of the incident light to pass through.

[0017] In the MALDI ion source 300, the laser light emitted from the laser light source 202 is reflected by the dichroic mirror 205, passes through the wave plate 301 and the polarization beam splitter 302, respectively, passes through the window 204, and enters the chamber 201, thereby irradiating the sample on the sample disk 210. In addition, the light from the sample passes through the window 204 and is received by the camera 203. Then, the irradiation position of the laser light is adjusted based on the imaging result of the camera 203.

[0018] At this time, in the MALDI ion source 300, the polarization direction of the laser light incident on the polarization beam splitter 302 is changed by rotating the wave plate 301. Then, in the polarization beam splitter 302, the laser light is adjusted to the light amount (intensity) of the laser light corresponding to the polarization direction of the laser light and then irradiated to the sample. Therefore, the laser light is irradiated to the sample with an appropriate intensity.

[0019] In the above-mentioned structure, the number of components increases, which leads to the disadvantage of large-scale device and high cost. Figure 3 In the MALDI ion source 200, the number of components in the region from the laser light source 202 to the dichroic mirror 205 increases. Figure 4 In the MALDI ion source 300 , the number of components in the region from the dichroic mirror 205 to the window 204 increases.

[0020] The present invention has been made in view of the above-mentioned actual situation, and an object of the present invention is to provide a MALDI ion source and a mass spectrometer that can suppress an increase in the number of components and thereby achieve miniaturization and cost reduction.

[0021] Solutions for solving problems

[0022] (1) The MALDI ion source involved in the present invention is a MALDI ion source that ionizes a sample by MALDI. The MALDI ion source includes a laser light source, a camera, an optical element, and an energy adjustment component. The laser light source emits laser light. The camera receives light from the sample irradiated with the laser light. The optical element makes the optical axis of the laser irradiated to the sample coaxial with the optical axis of the light from the sample irradiated with the laser light to the camera. The energy adjustment component adjusts the energy of the laser after the optical axis is made coaxial with the optical axis of the light to the camera by the optical element. The energy adjustment component rotates around the optical axis of the laser light to adjust the energy of the laser light.

[0023] According to this structure, in the MALDI ion source, the laser light from the laser light source passes through the optical element and then has its energy adjusted in the energy adjustment member. Then, the laser light with the adjusted energy is irradiated toward the sample. In addition, the energy adjustment member adjusts the energy of the laser light by rotating itself.

[0024] Therefore, in the MALDI ion source, only by providing a rotatable energy adjustment member, it is possible to adjust the energy of the laser light and irradiate the sample with the laser light.

[0025] As a result, it is possible to suppress an increase in the number of components, thereby achieving downsizing and cost reduction.

[0026] (2) In addition, the energy adjustment member may be a member whose transmittance differs depending on the polarization direction of the transmitted light.

[0027] According to such a configuration, the energy adjustment member can be simplified in structure.

[0028] (3) In addition, the MALDI ion source may further include a chamber. A sample may be placed inside the chamber. The laser light source, the camera, the optical element, and the energy adjustment member may be placed outside the chamber.

[0029] According to this structure, reflected light and scattered light generated in the MALDI ion source are shielded by the chamber.

[0030] Therefore, it is possible to suppress the reflected light and scattered light generated in the MALDI ion source from being irradiated onto the sample.

[0031] (4) In addition, the MALDI ion source may further include an attenuator member. The attenuator member is provided around the energy adjustment member with the optical axis of the laser as the center, and the attenuator member attenuates light reflected by the energy adjustment member. The attenuator member is annular.

[0032] According to this configuration, reflected light and scattered light generated by the laser beam incident on the energy adjustment member can be shielded by the attenuator member.

[0033] Therefore, it is possible to suppress the reflected light and scattered light generated by the energy adjustment member from being irradiated onto the sample.

[0034] (5) In addition, the mass spectrometer according to the present invention comprises the MALDI ion source, a mass separation unit, and a detection unit. The mass separation unit performs mass separation on ions generated by the MALDI ion source. The detection unit detects ions mass separated by the mass separation unit.

[0035] Effects of the Invention

[0036] According to the present invention, in a MALDI ion source, the energy of the laser light from the laser light source is adjusted in the energy adjustment member after passing through the optical element. Then, the laser light with the adjusted energy is irradiated toward the sample. In addition, the energy adjustment member adjusts the energy of the laser light by rotating itself. Therefore, in the MALDI ion source, only a rotatable energy adjustment member is provided to adjust the energy of the laser light and irradiate the laser light to the sample. As a result, the number of components can be suppressed from increasing, thereby achieving miniaturization and cost reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram showing a configuration example of a mass spectrometer according to one embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram showing a configuration example of a MALDI ion source according to one embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram showing a first structural example of a MALDI ion source conceivable from a conventional structure.

[0040] Figure 4 This is a schematic diagram showing a configuration example of a second MALDI ion source conceived from a conventional configuration. DETAILED DESCRIPTION

[0041] 1. Structure of mass spectrometry device

[0042] Figure 1 1 is a schematic diagram showing a configuration example of a mass spectrometer 10 according to an embodiment of the present invention. The mass spectrometer 10 is, for example, a matrix-assisted laser desorption ionization ion trap time-of-flight mass spectrometer (MALDI-IT-TOFMS).

[0043] The mass spectrometer 10 includes, for example, a MALDI ion source 1 , an ion trap 12 , a TOFMS (Time of Flight Mass Spectrometer) 13 , and a main body 100 .

[0044] The main body 100 is formed in a hollow shape. The MALDI ion source 1, the ion trap 12, and the TOFMS 13 are arranged in the main body 100. For example, a first chamber 101 and a second chamber 102 are formed in the main body 100. In this example, the first chamber 101 forms a space for accommodating the MALDI ion source 1. On the other hand, the second chamber 102 forms a space for accommodating the ion trap 12 and the TOFMS 13.

[0045] The first chamber 101 and the second chamber 102 are connected to each other via the opening 103. That is, the first chamber 101 and the second chamber 102 are partitioned by a partition wall 104, and the first chamber 101 and the second chamber 102 are connected to each other via the opening 103 formed in the partition wall 104. The first chamber 101 and the second chamber 102 are made into a vacuum state by a vacuum pump (not shown) or the like.

[0046] The MALDI ion source 1 ionizes a sample by MALDI and supplies the obtained ions to the ion trap 12. The sample is prepared in a concentrated state on, for example, a sample disk 20, and each sample disk 20 is placed in the MALDI ion source 1 when performing analysis.

[0047] The ion trap 12 is, for example, a three-dimensional quadrupole type.

[0048] A flight space 131 is formed in the TOFMS 13. In addition, an ion detector 132 is provided in the TOFMS 13. The TOFMS 13 constitutes an example of a mass separation unit. The ion detector 132 constitutes an example of a detection unit.

[0049] When using the mass spectrometer 10, first, laser light is irradiated onto the sample using MALDI (matrix-assisted laser desorption ionization) in the MALDI ion source 1. The sample is thereby vaporized together with the matrix in a vacuum, and the sample is ionized by gain and loss of protons between the sample and the matrix.

[0050] Then, the ions obtained by the MALDI ion source 1 are captured by the ion trap 12. In the ion trap 12, a part of the captured ions is selectively retained in the ion trap 12 and fragmented by CID (collision induced fragmentation). The fragmented ions are supplied from the ion trap 12 to the TOFMS 13.

[0051] In the TOFMS 13, ions flying through the flight space 131 are detected by the ion detector 132. Specifically, the ions accelerated by the electric field formed in the flight space 131 are separated in time according to the mass-to-charge ratio (mass-separated) while flying in the flight space 131, and are sequentially detected by the ion detector 132. Thus, the relationship between the mass-to-charge ratio and the detection intensity in the ion detector 132 is measured as a spectrum, thereby realizing mass spectrometry analysis.

[0052] 2. Structure of MALDI ion source

[0053] Figure 2 It is a schematic diagram showing a configuration example of a MALDI ion source 1 according to one embodiment of the present invention.

[0054] The MALDI ion source 1 includes a laser light source 2, a chamber 3, a camera 4, a reflector 5, a polarization beam splitter 6, and an attenuator member 7. The laser light source 2 and the camera 4 are disposed at intervals from the chamber 3. The reflector 5, the polarization beam splitter 6, and the attenuator member 7 are disposed between the chamber 3 and the camera 4.

[0055] The chamber 3 is formed in a box shape. A window sheet 8 is provided on the peripheral wall of the chamber 3. The window sheet 8 is arranged to be spaced apart from the camera 4. A sample placed on a sample disk 20 is accommodated in the chamber 3. The sample disk 20 (the sample placed on the sample disk 20) ​​and the window sheet 8 are opposed to each other.

[0056] The camera 4 includes a lens, a CCD, and the like (not shown).

[0057] The reflector 5 is disposed between the chamber 3 and the camera 4, and is opposite to the laser light source 2. The reflector 5 is, for example, a dichroic mirror. When the reflector 5 is a dichroic mirror, the reflector 5 reflects only light of a specific wavelength and transmits light of other wavelengths. In addition, the reflector 5 may also be a semi-transparent and semi-reflective mirror. The reflector 5 constitutes an example of an optical element.

[0058] The polarization beam splitter 6 is disposed between the reflector 5 and the window 8. The polarization beam splitter 6 is a component whose transmittance varies depending on the polarization direction of the transmitted light. The polarization beam splitter 6 can be in a cubic shape or in a plate shape (mirror shape). The polarization beam splitter 6 is formed to be rotatable. The polarization beam splitter 6 constitutes an example of an energy adjustment component.

[0059] Specifically, the polarization beam splitter 6 is provided on a rotating part (not shown) configured to be rotatable. The rotating part can rotate around the optical axis of the laser light reflected by the reflector 5 and directed toward the sample (the optical axis of the laser light irradiated to the sample), and the rotating part is rotated by applying a driving force from a driving source such as a motor (not shown). Moreover, due to the rotation of the rotating part, the polarization beam splitter 6 rotates around the optical axis of the laser light (the optical axis of the laser light irradiated to the sample).

[0060] The attenuator member 7 is formed in a ring shape and surrounds the polarization beam splitter 6 (is arranged around the polarization beam splitter 6). Specifically, the attenuator member 7 is arranged to be centered on the optical axis of the laser beam irradiated to the sample. The attenuator member 7 includes a base portion 71 and a shielding portion 72. The base portion 71 is formed in a ring shape. Specifically, the base portion 71 is, for example, in a circular ring shape. The shielding portion 72 is formed on the inner circumferential surface of the base portion 71. The shielding portion 72 is configured to attenuate light. Specifically, the shielding portion 72 is, for example, an attenuation layer formed by applying a black paint on the inner circumferential surface of the base portion 71.

[0061] 3. Operation of MALDI ion source

[0062] When the MALDI ion source 1 is used, light of a specific wavelength in the laser light emitted from the laser light source 2 is reflected by the reflector 5, passes through the polarization beam splitter 6, and enters the chamber 3. Then, the laser light that has passed through the polarization beam splitter 6 is irradiated to the sample on the sample disk 20. In addition, the light from the sample passes through the window 8, the polarization beam splitter 6, and the reflector 5 and is received by the camera 4. In this way, in the MALDI ion source 1, the optical axis of the laser light irradiated to the sample and the optical axis of the light from the sample irradiated with the laser light to the camera 4 are arranged to be coaxial by the reflector 5.

[0063] At this time, the polarization beam splitter 6 is appropriately rotated, and the laser light passes through the polarization beam splitter 6 at a transmittance corresponding to the polarization direction. Specifically, a driving force from a driving source (not shown) is applied to the rotating part (not shown), so that the polarization beam splitter 6 rotates by a predetermined angle. As a result, the polarization direction of the laser light relative to the polarization beam splitter 6 changes, and the transmittance of the laser light passing through the polarization beam splitter 6 changes. That is, the energy of the laser light reflected by the reflector 5 is adjusted by the polarization beam splitter 6. Then, the laser light with the adjusted energy is irradiated to the sample.

[0064] The angle of rotation of polarization beam splitter 6 is determined, for example, so that laser light of a light quantity (intensity) desired by the user passes through polarization beam splitter 6. This determination is performed, for example, by the user operating an operation unit (not shown) provided in mass spectrometer 10.

[0065] In this case, the user can operate the operation unit while checking the spectrum to adjust the transmittance of the laser light transmitted through the polarization beam splitter 6 so that the intensity value shown in the spectrum becomes a predetermined value. In addition, in the mass spectrometer 10, the light amount (intensity) of the laser light transmitted through the polarization beam splitter 6 can be set in advance, and the polarization beam splitter 6 can be automatically rotated so that the laser light of the set light amount can be transmitted through the polarization beam splitter 6.

[0066] In addition, the reflected light and scattered light generated by the laser beam incident on the polarization beam splitter 6 are attenuated by the attenuator member 7. Specifically, when the shielding portion 72 is an attenuation layer formed by a black paint, the reflected light and scattered light generated by the polarization beam splitter 6 are absorbed and attenuated by the shielding portion 72. Therefore, it is possible to suppress the reflected light and scattered light generated by the polarization beam splitter 6 from irradiating the sample in the chamber 3. In addition, the light not absorbed by the attenuator member 7 and other reflected light and / or scattered light generated in the MALDI ion source 1 are shielded by the peripheral wall of the chamber 3.

[0067] In this way, the MALDI ion source 1 can adjust the light intensity of the laser light only by providing the rotatable polarization beam splitter 6. In addition, the sample can be irradiated with the laser light at an appropriate intensity.

[0068] 4. Effect

[0069] (1) According to this embodiment, Figure 1 As shown, the mass spectrometer 10 is provided with a MALDI ion source 1. Figure 2 As shown, in the MALDI ion source 1, the laser light from the laser light source 2 is reflected by the reflector 5 and then the energy is adjusted in the polarization beam splitter 6. Then, the laser light with the adjusted energy is irradiated toward the sample. In addition, the polarization beam splitter 6 adjusts the energy of the laser light by rotating itself.

[0070] Therefore, in the MALDI ion source 1 , only by providing the rotatable polarization beam splitter 6 , it is possible to adjust the energy of the laser light and irradiate the sample with the laser light.

[0071] As a result, in the MALDI ion source 1 (mass spectrometer 10 ), it is possible to suppress an increase in the number of components, thereby achieving miniaturization and cost reduction.

[0072] (2) According to the present embodiment, the polarization beam splitter 6 as an example of the energy adjustment member is a member whose transmittance differs depending on the polarization direction of the transmitted light.

[0073] Therefore, the energy adjustment member can be made into a simple structure.

[0074] (3) According to the present embodiment, the MALDI ion source 1 includes the chamber 3 . The sample disk 20 (the sample disk 20 and the sample) is provided in the chamber 3 . The laser light source 2 , the camera 4 , the mirror 5 , and the polarization beam splitter 6 are provided outside the chamber 3 .

[0075] Therefore, the reflected light and scattered light generated in the MALDI ion source 1 are shielded by the peripheral wall of the chamber 3 .

[0076] As a result, it is possible to suppress the reflected light and scattered light generated in the MALDI ion source 1 from being irradiated onto the sample.

[0077] (4) In addition, according to this embodiment, if Figure 2 As shown in FIG. 1 , the MALDI ion source 1 includes an attenuator member 7 . The attenuator member 7 is provided around the polarization beam splitter 6 .

[0078] Therefore, in the MALDI ion source 1 , the reflected light and scattered light generated by the laser light being incident on the polarization beam splitter 6 can be shielded by the attenuator member 7 .

[0079] As a result, it is possible to suppress the reflected light and scattered light generated by the polarization beam splitter 6 from being irradiated onto the sample.

[0080] 5. Modifications

[0081] In the above embodiment, the attenuator member 7 is described as a member having a shielding portion 72 that absorbs light. However, the attenuator member 7 may also attenuate light by causing multiple reflections. For example, the attenuator member 7 may be an annular member, and its peripheral surface is a shape that tapers toward the outside of the polarization beam splitter 6. According to this structure, when the light that has already hit the inner peripheral surface of the polarization beam splitter 6 is irradiated, the light repeats multiple reflections and is attenuated.

[0082] Description of Reference Numerals

[0083] 1: MALDI ion source; 2: laser light source; 3: chamber; 4: camera; 5: reflector; 6: polarization beam splitter; 7: attenuator component; 10: mass spectrometer; 13: TOFMS; 71: base unit; 72: shielding unit; 132: ion detector.

Claims

1. A MALDI ion source for ionizing a sample by MALDI, wherein the MALDI ion source comprises: a laser light source that emits laser light; a camera that receives light from the sample irradiated with the laser; an optical element that makes the optical axis of the laser light irradiated onto the sample and the optical axis of the light from the sample irradiated with the laser light toward the camera coaxial; and an energy adjustment member for adjusting the energy of the laser light after the optical axis is made coaxial with the optical axis of the light going to the camera by the optical element, in, The energy adjustment member adjusts the energy of the laser light by rotating around the optical axis of the laser light after the optical axis is made coaxial with the optical axis of the light going to the camera by the optical element. wherein the energy adjustment member is disposed between the optical element and the sample and on the optical axis of the light going to the camera, and The energy adjustment member is a polarization beam splitter that can rotate around an optical axis of a laser beam whose optical axis is coaxial with an optical axis of the light going to the camera.

2. The MALDI ion source according to claim 1, characterized in that The energy adjustment member is a member whose transmittance varies depending on the direction of polarization of the transmitted light.

3. The MALDI ion source according to claim 1, characterized in that A chamber is also provided, and a sample is arranged inside the chamber. The laser light source, the camera, the optical element, and the energy adjustment component are arranged outside the chamber.

4. The MALDI ion source according to claim 1, characterized in that The invention further comprises an annular attenuator member provided around the energy adjustment member with the optical axis of the laser light as the center, the attenuator member being configured to attenuate the light reflected by the energy adjustment member.

5. A mass spectrometry device, characterized in that: have: The MALDI ion source according to claim 1; a mass separation unit for performing mass separation on ions generated by the MALDI ion source; and A detection unit detects the ions separated by mass by the mass separation unit.

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