JP6699770B2 - MALDI ion source and mass spectrometer - Google Patents

Description

  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.

  Conventionally, a MALDI ion source that ionizes a sample by MALDI has been used. For example, when a MALDI ion source is used in the mass spectrometer, the sample is irradiated with laser light to ionize the sample. Then, the ionized sample is temporally separated according to the mass-to-charge ratio in the mass separation unit, and sequentially detected by the detector (for example, refer to Patent Document 1 below).

  In a mass spectrometer using a MALDI ion source, it is necessary to irradiate a sample with a laser at an appropriate intensity in order to create an accurate spectrum. Therefore, in a mass spectrometer using a MALDI ion source, a mechanism for adjusting the intensity of laser is used.

International publication 2011/081180

  As a MALDI ion source provided with a mechanism for adjusting the laser intensity, for example, it is possible to use the MALDI ion source 200 shown in FIG.

  The MALDI ion source 200 shown in FIG. 3 includes a chamber 201, a laser light source 202, and a camera 203. Each of the laser light source 202 and the camera 203 is arranged apart from the chamber 201.

  A window plate 204 is provided on the peripheral wall of the chamber 201. The camera 203 is arranged apart from the window plate 204. A dichroic mirror 205 is provided between the camera 203 and the window plate 204.

A rotary density filter 206 and a beam expander 207 are provided between the laser light source 202 and the dichroic mirror 205. Specifically, the rotation 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 rotation density filter 206 is rotatable about the optical axis of the light traveling from the laser light source 202 to the dichroic mirror 205. The rotation density filter 206 transmits light with a light amount according to the rotation position. The beam expander 207 is for expanding the diameter of the transmitted laser light.
The chamber 201 accommodates the sample placed on the sample plate 210.

  In the MALDI ion source 200, the laser light emitted from the laser light source 202 passes through the beam expander 207 and then through the rotational density filter 206. The laser light is reflected by the dichroic mirror 205, passes through the window plate 204, enters the chamber 201, and is irradiated onto the sample on the sample plate 210. Light from the sample passes through the window plate 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.

  At this time, in the MALDI ion source 200, the light amount (intensity) of the laser light with which the sample is irradiated is adjusted by rotating the rotation density filter 206. Therefore, the laser light is applied to the sample with an appropriate intensity.

  Further, as the MALDI ion source provided with a mechanism for adjusting the laser intensity, for example, it is possible to use the MALDI ion source 300 shown in FIG. In the MALDI ion source 300 of FIG. 4, the same members as those of the MALDI ion source 200 of FIG. 3 are designated by the same reference numerals.

  In the MALDI ion source 300 shown in FIG. 4, no optical element is provided between the laser light source 202 and the dichroic mirror 205. A wavelength plate 301 and a polarization beam splitter 302 are provided between the dichroic mirror 205 and the window plate 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 plate 204 side. The wave plate 301 is rotatable around the optical axis of the light traveling from the dichroic mirror 205 to the window plate 204. The wave plate 301 is for changing the polarization direction of incident light. The wave plate 301 changes the polarization direction of light according to the rotation position. The polarization beam splitter 302 transmits light with an amount of light according to the polarization direction of incident light.

  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, passes through the window plate 204, and enters the chamber 201. The sample on the sample plate 210 is irradiated. Light from the sample passes through the window plate 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.

  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 light amount (intensity) of the laser light is adjusted according to the polarization direction of the laser light, and the laser light is applied to the sample. Therefore, the sample is irradiated with the laser light at an appropriate intensity.

  In the above-mentioned configuration, since the number of parts is increased, there are problems that the device becomes large and the cost becomes high. Specifically, the MALDI ion source 200 of FIG. 3 has a large number of components, especially in the region from the laser light source 202 to the dichroic mirror 205, and the MALDI ion source 300 of FIG. The number of parts increases in the area up to 204.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a MALDI ion source and a mass spectrometer which can suppress an increase in the number of parts and can achieve downsizing and cost reduction.

(1) The MALDI ion source according to 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 adjusting member. The laser light source emits laser light. The camera receives the light from the sample irradiated with the laser light. The optical element makes an optical axis of the laser light with which the sample is irradiated and an optical axis of light from the sample with which the laser light is irradiated toward the camera coaxial with each other. The energy adjusting member adjusts the energy of the laser light after the optical element makes the optical axis coaxial with the optical axis of the light directed to the camera. The energy adjusting member adjusts the energy of the laser light by rotating around the optical axis of the laser light.

  According to such a configuration, in the MALDI ion source, the energy of the laser light from the laser light source is adjusted by the energy adjusting member after passing through the optical element. Then, the laser beam whose energy has been adjusted is irradiated toward the sample. Further, the energy adjusting member adjusts the energy of the laser light by rotating itself.

Therefore, in the MALDI ion source, the energy of the laser beam can be adjusted and the sample can be irradiated with the laser beam only by providing a rotatable energy adjusting member.
As a result, it is possible to suppress an increase in the number of parts, and it is possible to realize miniaturization and cost reduction.

(2) Further, the energy adjusting member may be a member having a different transmittance depending on the polarization direction of transmitted light.

  With such a configuration, the energy adjusting member can have a simple configuration.

(3) Further, the MALDI ion source may further include a chamber. A sample is installed inside the chamber. The laser light source, the camera, the optical element, and the energy adjusting member may be provided outside the chamber.

With such a configuration, the reflected light and scattered light generated by the MALDI ion source are blocked by the chamber.
Therefore, it is possible to prevent the sample from being irradiated with the reflected light or the scattered light generated by the MALDI ion source.

(4) Further, the MALDI ion source may further include a damper member. The damper member is provided around the energy adjusting member around the optical axis of the laser light and attenuates the light reflected by the energy adjusting member. The damper member is annular.

With such a configuration, the damper member can shield the reflected light and the scattered light generated when the laser light enters the energy adjusting member.
Therefore, it is possible to prevent the sample from being irradiated with the reflected light or the scattered light generated by the energy adjusting member.

(5) Further, the mass spectrometer according to the present invention includes the MALDI ion source, a mass separation unit, and a detection unit. The mass separation unit mass-separates the ions generated in the MALDI ion source. The detection unit detects the ions that have been mass-separated by the mass separation unit.

  According to the present invention, in the MALDI ion source, the energy of the laser light from the laser light source is adjusted by the energy adjusting member after passing through the optical element. Then, the laser beam whose energy has been adjusted is irradiated toward the sample. Further, the energy adjusting member adjusts the energy of the laser light by rotating itself. Therefore, in the MALDI ion source, the energy of the laser beam can be adjusted and the sample can be irradiated with the laser beam only by providing a rotatable energy adjusting member. As a result, it is possible to suppress an increase in the number of parts, and it is possible to realize miniaturization and cost reduction.

It is the schematic which showed the structural example of the mass spectrometer which concerns on one Embodiment of this invention. It is the schematic which showed the structural example of the MALDI ion source which concerns on one Embodiment of this invention. It is the schematic which showed the structural example of the 1st MALDI ion source considered from the conventional structure. It is the schematic which showed the structural example of the 2nd MALDI ion source considered from the conventional structure.

1. Configuration of Mass Spectrometer FIG. 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).
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.

  The main body 100 is formed in a hollow shape. Inside the main body 100, a MALDI ion source 1, an ion trap 12, a TOFMS 13 and the like are provided. Inside the main body 100, for example, a first chamber 101 and a second chamber 102 are formed. In this example, the first chamber 101 forms a space that houses the MALDI ion source 1. On the other hand, the second chamber 102 forms a space that houses the ion trap 12 and the TOFMS 13.

  The first chamber 101 and the second chamber 102 communicate with each other through the opening 103. That is, the first chamber 101 and the second chamber 102 are partitioned by the partition wall 104, and communicate with each other through the opening 103 formed in the partition wall 104. The inside of the first chamber 101 and the inside of the second chamber 102 are brought into a vacuum state by a vacuum pump or the like not shown.

The MALDI ion source 1 ionizes the sample by MALDI and supplies the obtained ions to the ion trap 12. The sample is prepared, for example, in a concentrated state on the sample plate 20, and is set in the MALDI ion source 1 together with the sample plate 20 during analysis.
The ion trap 12 is, for example, a three-dimensional quadrupole type.

  A flight space 131 is formed in the TOFMS 13. Further, the TOFMS 13 is provided with an ion detector 132. The TOFMS 13 constitutes an example of the mass separation section. The ion detector 132 constitutes an example of a detection unit.

  When using the mass spectrometer 10, first, in the MALDI ion source 1, a sample is irradiated with a laser using MALDI (Matrix Assisted Laser Desorption/Ionization Method). As a result, the sample is vaporized in a vacuum together with the matrix, and the sample is ionized by the exchange of protons between the sample and the matrix.

  Then, the ions obtained by the MALDI ion source 1 are captured by the ion trap 12. In the ion trap 12, some of the trapped ions are selectively left in the ion trap 12 and cleaved by CID (collision induced dissociation). The ions thus cleaved are supplied from the ion trap 12 to the TOFMS 13.

  In the TOFMS 13, the ions flying in 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 temporally separated (mass separated) according to the mass-to-charge ratio while flying in the flight space 131, and the ion detector 132 is used. Are sequentially detected by. Thereby, the relationship between the mass-to-charge ratio and the detection intensity in the ion detector 132 is measured as a spectrum, and the mass analysis is realized.

2. Configuration of MALDI Ion Source FIG. 2 is a schematic diagram showing a configuration example of the MALDI ion source 1 according to one embodiment of the present invention.
The MALDI ion source 1 includes a laser light source 2, a chamber 3, a camera 4, a mirror 5, a polarization beam splitter 6, and a damper member 7. Each of the laser light source 2 and the camera 4 is arranged at a distance from the chamber 3. The mirror 5, the polarization beam splitter 6, and the damper member 7 are arranged between the chamber 3 and the camera 4.

The chamber 3 is formed in a box shape. A window plate 8 is provided on the peripheral wall of the chamber 3. The window plate 8 is arranged apart from the camera 4. A sample placed on the sample plate 20 is accommodated in the chamber 3. The sample plate 20 (the sample placed on the sample plate 20) faces the window plate 8.
The camera 4 is provided with a lens, a CCD and the like (not shown).

  The mirror 5 is arranged between the chamber 3 and the camera 4 and faces the laser light source 2. The mirror 5 is, for example, a dichroic mirror. When the mirror 5 is a dichroic mirror, the mirror 5 reflects only light of a specific wavelength and transmits light of other wavelengths. The mirror 5 may be a half mirror. The mirror 5 constitutes an example of an optical element.

  The polarization beam splitter 6 is arranged between the mirror 5 and the window plate 8. The polarization beam splitter 6 is a member having a different transmittance depending on the polarization direction of transmitted light. The polarization beam splitter 6 may have a cube shape or a plate shape (mirror shape). The polarization beam splitter 6 is rotatable. The polarization beam splitter 6 constitutes an example of an energy adjusting member.

  Specifically, the polarization beam splitter 6 is provided on a rotating unit (not shown) configured to be rotatable. The rotating portion is rotatable about an optical axis of laser light reflected by the mirror 5 and directed to the sample (optical axis of laser light irradiated on the sample), and is a driving source (not shown) such as a motor. ), it is rotated by applying a driving force. Then, as the rotating part rotates, the polarization beam splitter 6 rotates about the optical axis of the laser light (the optical axis of the laser light with which the sample is irradiated).

  The damper member 7 is formed in an annular shape and surrounds the polarization beam splitter 6 (provided around the polarization beam splitter 6). Specifically, the damper member 7 is arranged so that the optical axis of the laser beam with which the sample is irradiated is the center. The damper member 7 includes a base portion 71 and a shielding portion 72. The base 71 is formed in a ring shape. Specifically, the base part 71 has, for example, an annular shape. The shield 72 is formed on the inner peripheral surface of the base 71. The shield 72 is configured to attenuate light. Specifically, the shielding part 72 is, for example, an attenuation layer formed by applying black paint to the inner peripheral surface of the base part 71.

3. Operation of MALDI Ion Source When using the MALDI ion source 1, light of a specific wavelength in the laser light emitted from the laser light source 2 is reflected by the mirror 5 and then passes through the polarization beam splitter 6 to cause the chamber 3 Enter inside. Then, the laser light transmitted through the polarization beam splitter 6 is applied to the sample on the sample plate 20. The light from the sample passes through the window plate 8, the polarization beam splitter 6 and the mirror 5 and is received by the camera 4. As described above, in the MALDI ion source 1, the optical axis of the laser light with which the sample is irradiated and the optical axis of the light that travels from the sample with the laser light toward the camera 4 are coaxially arranged by the mirror 5.

  At this time, the polarization beam splitter 6 appropriately rotates, so that the laser light passes through the polarization beam splitter 6 with a transmittance according to the direction of polarization. Specifically, a driving force from a driving source (not shown) is applied to a rotating unit (not shown), so that the polarization beam splitter 6 rotates by a predetermined angle. As a result, the polarization direction of the laser light with respect to the polarization beam splitter 6 changes, and the transmission amount of the laser light that passes through the polarization beam splitter 6 changes. That is, the energy of the laser beam reflected by the mirror 5 is adjusted by the polarization beam splitter 6. Then, the sample is irradiated with the laser light whose energy has been adjusted.

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

  In this case, the user can adjust the transmission amount of the laser light transmitted through the polarization beam splitter 6 by operating the operation unit while checking the spectrum so that the intensity value indicated by the spectrum becomes a predetermined value. .. In the mass spectrometer 10, the light quantity (intensity) of the laser light that passes through the polarization beam splitter 6 is preset, and the polarization beam splitter 6 is set so that the laser light passes through the polarization beam splitter 6 by the set light quantity. May be rotated automatically.

  Further, the damper member 7 attenuates the reflected light and the scattered light generated by the laser light incident on the polarization beam splitter 6. Specifically, when the shielding portion 72 is an attenuating layer formed of black paint, reflected light or scattered light generated by the polarization beam splitter 6 is absorbed by the shielding portion 72 and attenuated. Therefore, the sample in the chamber 3 is prevented from being irradiated with the reflected light or the scattered light generated by the polarization beam splitter 6. Further, the light not absorbed by the damper member 7 and other reflected light and scattered light generated in the MALDI ion source 1 are shielded by the peripheral wall of the chamber 3.

  As described above, in the MALDI ion source 1, the amount of laser light can be adjusted only by providing the rotatable polarization beam splitter 6. Then, the sample can be irradiated with the laser at an appropriate intensity.

4. Action and Effect (1) According to the present embodiment, as shown in FIG. 1, the mass spectrometer 10 includes the MALDI ion source 1. As shown in FIG. 2, in the MALDI ion source 1, after the laser light from the laser light source 2 is reflected by the mirror 5, the energy is adjusted by the polarization beam splitter 6. Then, the laser light whose energy has been adjusted is irradiated toward the sample. Further, the polarization beam splitter 6 adjusts the energy of the laser light by rotating itself.

Therefore, in the MALDI ion source 1, it is possible to adjust the energy of the laser beam and irradiate the sample with the laser beam only by providing the rotatable polarization beam splitter 6.
As a result, in the MALDI ion source 1 (mass spectrometer 10), it is possible to suppress an increase in the number of parts, and it is possible to realize miniaturization and cost reduction.
(2) Further, according to the present embodiment, the polarization beam splitter 6, which is an example of the energy adjusting member, is a member having a different transmittance depending on the polarization direction of the transmitted light.
Therefore, the energy adjusting member can have a simple structure.

(3) Further, according to this embodiment, the MALDI ion source 1 includes the chamber 3. A sample plate 20 (sample plate 20 and sample) is installed 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.
Therefore, the reflected light and scattered light generated by the MALDI ion source 1 are shielded by the peripheral wall of the chamber 3.
As a result, it is possible to prevent the sample from being irradiated with the reflected light or scattered light generated by the MALDI ion source 1.

(4) Further, according to the present embodiment, as shown in FIG. 2, the MALDI ion source 1 includes the damper member 7. The damper member 7 is provided around the polarization beam splitter 6.
Therefore, in the MALDI ion source 1, the damper member 7 can shield reflected light and scattered light generated when the laser light enters the polarization beam splitter 6.
As a result, it is possible to prevent the sample from being irradiated with the reflected light or the scattered light generated by the polarization beam splitter 6.

5. Modifications In the above embodiments, the damper member 7 has been described as a member including the shielding portion 72 that absorbs light. However, the damper member 7 may be one that attenuates light by multiple reflection. For example, the damper member 7 may be a ring-shaped member, and the peripheral surface thereof may be tapered toward the outside of the polarization beam splitter 6. With such a configuration, when the light hitting the inner peripheral surface of the polarization beam splitter 6 hits, the light is repeatedly reflected and attenuated.

1 MALDI Ion Source 2 Laser Light Source 3 Chamber 4 Camera 5 Mirror 6 Polarizing Beam Splitter 7 Damper Member 10 Mass Spectrometer 13 TOFMS
71 Base part 72 Shielding part 132 Ion detector

Claims (5)

A MALDI ion source for ionizing a sample by MALDI, comprising:
A laser light source that emits laser light,
A camera that receives light from the sample irradiated with the laser light,
An optical element that makes the optical axis of the laser beam with which the sample is irradiated and the optical axis of the light that is directed from the sample with the laser beam toward the camera coaxial with each other,
An energy adjusting member for adjusting the energy of the laser light after the optical axis is made coaxial with the optical axis of light directed to the camera by the optical element,
The energy adjusting member is a polarization beam splitter having a different transmittance depending on the polarization direction of the transmitted light, and rotating the optical axis of the laser light to adjust the energy of the laser light. Characteristic MALDI ion source. A MALDI ion source for ionizing a sample by MALDI, comprising:
A laser light source that emits laser light,
A camera that receives light from the sample irradiated with the laser light,
An optical element that makes the optical axis of the laser beam with which the sample is irradiated and the optical axis of the light that is directed from the sample with the laser beam toward the camera coaxial with each other,
An energy adjusting member for adjusting the energy of the laser light after the optical axis is coaxial with the optical axis of light directed to the camera by the optical element ,
An annular damper member is provided around the energy adjusting member around the optical axis of the laser light, and an annular damper member for attenuating light reflected by the energy adjusting member ,
The MALDI ion source, wherein the energy adjusting member adjusts the energy of the laser light by rotating around the optical axis of the laser light. Further comprising a chamber in which the sample is installed,
The MALDI ion source according to claim 1 or 2, wherein the laser light source, the camera, the optical element, and the energy adjusting member are provided outside the chamber. Wherein provided around the optical axis of the laser beam around the energy adjustment member, according to claim 1, further comprising an annular damper member for damping the light reflected by said energy adjustment member MALDI ion source. A MALDI ion source according to any one of claims 1 to 4,
A mass separator for mass-separating the ions generated in the MALDI ion source;
A mass spectroscope comprising: a detection unit that detects the ions that have been mass-separated by the mass separation unit.

Images