Sample support

Abstract

This sample support comprises a substrate that has: a first surface; a second surface that is on the opposite side from the first surface; a side surface that connects an edge part of the first surface and an edge part of the second surface; and voids that are distributed to as to be open on at least the first surface and the side surface. The substrate is formed of a plurality of particles that are connected to each other. Among the plurality of particles, a plurality of side surface particles that constitute the side surface have, as at least part of the outer surfaces thereof, a rough surface in which an uneven structure is formed.

Description

Sample Support

[0001] The present disclosure relates to sample supports.

[0002] A known sample support used for sample ionization is one having a porous substrate with a main surface and a side surface (see, for example, Patent Document 1). The porous substrate of such a sample support includes irregularly distributed pores that open to the main surface. This sample support makes it possible to appropriately adjust the amount of sample remaining on the main surface of the porous substrate and to suitably ionize the components of the sample.

[0003] Japanese Patent Application Laid-Open No. 2022-43571

[0004] In the above-mentioned sample support, high precision in sample analysis is required, and at the same time, ease of use (handling ability) of the sample support during analysis work is also required.

[0005] An object of the present disclosure is to provide a sample support that can improve the accuracy of analysis and also improve the ease of handling.

[0006] The present disclosure includes sample supports [1] to [8].

[0007] [1] A sample support for ionizing a sample, comprising a porous substrate having a first surface, a second surface opposite to the first surface, a side surface connecting an edge of the first surface with an edge of the second surface, and voids distributed so as to open to at least the first surface and the side surface, wherein the porous substrate is formed by a plurality of particles connected to each other, and at least a portion of the outer surfaces of a plurality of side particles constituting the side surface among the plurality of particles are roughened with an uneven structure formed thereon.

[0008] In the sample support of [1] above, the porous substrate includes voids opening to the first surface. This allows the sample, when introduced to the first surface of the porous substrate, to diffuse appropriately within the voids, thereby appropriately adjusting the amount of sample remaining on the first surface. As a result, the sample remaining on the first surface can be suitably ionized. Furthermore, the voids in the porous substrate also open to the side surfaces. This allows for efficient degassing of the porous substrate (i.e., gas accumulated in the voids is discharged from the side surfaces) when, for example, a sample support with a sample transferred to its first surface is introduced into a vacuum device. Furthermore, even when transferring a sample to the entire first surface, gas introduced into the substrate from the first surface can escape through the side openings, thereby preventing excess gas (residual gas) from accumulating inside the porous substrate and ultimately preventing uneven transfer due to the residual gas. Furthermore, at least a portion of the outer surface of the side surface of the porous substrate is roughened, with an uneven structure formed thereon. As a result, for example, when an operator holds the side of the porous substrate with his / her fingers or when the operator holds the side of the porous substrate with an instrument for supporting the sample support, the rough surface exhibits a non-slip function, thereby improving the handleability of the sample support. As described above, the sample support can achieve high-precision analysis and also improve handleability.

[0009] [2] The sample support of [1], wherein at least a portion of the plurality of side grains has a non-rough surface on the side opposite to the rough surface where the uneven structure is not formed.

[0010] According to the sample support of [2] above, by making the inner surface of the lateral particle a non-rough surface, it is possible to sufficiently ensure the bonding strength between the lateral particle and the particle located inside the lateral particle, and to prevent the lateral particle from spilling out, etc. Furthermore, by not providing an uneven structure on the inside of the lateral particle, it is possible to facilitate the flow of gas inside the lateral particle (for example, the flow of the residual gas described above) compared to when an uneven structure is formed on the inside of the lateral particle, and thus it is possible to preferably vent gas from the opening on the side.

[0011] [3] The sample support according to [1] or [2], wherein at least a portion of the plurality of side grains is formed from a material that emits ions in response to irradiation with an energy beam.

[0012] [4] A sample support according to any one of [1] to [3], wherein a substance that emits ions in response to irradiation with an energy beam is disposed on the rough surfaces of at least some of the side particles.

[0013] According to the sample support of [3] or [4] above, the first surface of the sample support is irradiated with an energy beam to ionize the components (molecules) of the sample present on the first surface, and the spatial distribution of the ionized components is visualized two-dimensionally. In the resulting image (hereinafter referred to as an "MSI image"), the area corresponding to the side surface of the porous substrate (i.e., the outer edge of the sample support) can be clearly identified. More specifically, because the rough surface has an uneven structure (edge ​​structure), the energy of the energy beam is easily absorbed by the edge portion of the rough surface. This allows the components of the material at the edge portion to be favorably ionized and easily desorbed, thereby making it possible to easily and accurately identify the area corresponding to the outer edge of the sample support in the MSI image. Furthermore, in the sample support of [4] above, ionization at the surface of the edge portion is more favorable, making it possible to easily and accurately identify the area corresponding to the outer edge of the sample support in the MSI image.

[0014] [5] A sample support according to any one of [1] to [4], further comprising a conductive layer provided on the surface of the porous substrate, wherein the conductive layer includes a first conductive region provided on the first surface so as not to block the openings of the voids on the first surface, and a second conductive region connected to the first conductive region and provided on the side surface so as not to block the openings of the voids on the side surface, and wherein the second conductive region is provided on the rough surfaces of at least a portion of the plurality of side particles, along the surface shape of the uneven structure.

[0015] When ionizing the components of the sample remaining on the first surface by irradiation with an energy beam (e.g., laser desorption ionization, etc.), it is necessary to apply a voltage to the conductive layer (first conductive region) on the first surface. In order to stably apply a voltage to the first conductive region, it is preferable to apply a voltage to the side surface as well, and it is preferable to provide a second conductive region on the side surface. Furthermore, by providing the second conductive region along the surface shape of the uneven structure on at least a portion of the rough surfaces of the multiple lateral particles, the same effect as in [4] above can be obtained.

[0016] [6] The sample support according to [5], wherein the thickness of the conductive layer in the second conductive region is smaller than the thickness of the conductive layer in the first conductive region.

[0017] According to the sample support of [6] above, by ensuring a constant thickness for the first conductive region on the first surface, a voltage can be stably applied to the first surface during analysis. On the other hand, by reducing the thickness of the conductive layer for the second conductive region on the side surface, the same effect as that of [4] above can be more suitably obtained.

[0018] [7] The sample support according to [5] or [6], wherein the first surface has a rectangular shape, and the conductive layer is not provided in portions corresponding to the four corners of the first surface.

[0019] According to the sample support of the above item [7], since the conductive layer is not provided on the portions corresponding to the four corners of the first surface, it is easy to visually distinguish between the portions of the first surface on which the conductive layer is provided and the portions corresponding to the four corners of the first surface. As a result, when aligning the stage with the sample support placed on the stage of a mass spectrometer, the portions corresponding to the four corners of the first surface can be used as markers, making alignment easier.

[0020] [8] The sample support according to any one of [1] to [7], wherein the side surface includes an inclined region that is inclined so as to widen outward as it moves from the first surface toward the second surface.

[0021] According to the sample support of the above item [8], the stability of the sample support can be improved when the sample support is placed on a sample stage or the like during analysis.

[0022] According to the present disclosure, it is possible to provide a sample support that can improve the accuracy of analysis and also improve the ease of handling.

[0023] 1. FIG. 2 is a perspective view of a sample support according to one embodiment. FIG. 3 is a cross-sectional view of the sample support taken along line II-II in FIG. 1. FIG. 4 is a schematic diagram showing a part of the porous structure on the first surface side of the porous substrate shown in FIG. 1. FIG. 5 is a schematic diagram showing a part of the porous structure on the side surface side of the porous substrate shown in FIG. 1. FIG. 6 is an SEM image of region A shown in FIG. 1. FIG. 7 is an SEM image of region B shown in FIG. 1. FIG. 8 is a diagram showing a part of the third step of a mass spectrometry method according to one embodiment. FIG. 9 is a configuration diagram of a mass spectrometry apparatus for carrying out a mass spectrometry method according to one embodiment. FIG. 10 is a schematic diagram for explaining the effect of the sample support shown in FIG. 1. FIG. 11 is a diagram showing an MSI image and a camera image of the boundary between a comparative example (left) and an example (right).

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, in the drawings, some parts are exaggerated to clearly illustrate the characteristics of the embodiments. Therefore, the dimensional ratios of the parts in the drawings may differ from the actual dimensional ratios.

[0025] [Sample Support] The sample support 1 shown in Figures 1 to 4 is used for ionizing a sample. The sample may contain, for example, a liquid component, and specific examples include a biological sample and a slice of fruit (e.g., strawberry). The sample support 1 includes a substrate (porous substrate) 2 and a conductive layer 3.

[0026] The substrate 2 has a first surface 2a, a second surface 2b opposite the first surface 2a, and a side surface 2c connecting an edge of the first surface 2a with an edge of the second surface 2b. As an example, the substrate 2 is formed in a rectangular plate shape. The thickness of the substrate 2 (the distance from the first surface 2a to the second surface 2b) is, for example, approximately 100 μm to 1500 μm. For convenience, in this specification and drawings, the thickness direction of the substrate 2 (i.e., the direction in which the first surface 2a and the second surface 2b face each other) is referred to as the Z-axis direction, a direction perpendicular to the Z-axis direction (the longitudinal direction of the substrate 2) is referred to as the X-axis direction, and a direction perpendicular to the Z-axis direction and the X-axis direction (the lateral direction of the substrate 2) is referred to as the Y-axis direction.

[0027] The first surface 2a is a surface on which a sample S to be analyzed (see FIGS. 7 and 8) is placed (transferred). The second surface 2b is a surface to be placed on a predetermined sample stage (for example, the support substrate 8 shown in FIGS. 7 and 8). As shown in FIG. 2, the side surface 2c includes an inclined region that slopes outward from the first surface 2a toward the second surface 2b. In this embodiment, the entire side surface 2c is an inclined region that slopes in a tapered manner as described above.

[0028] As shown in Figures 3 and 4, the substrate 2 includes voids 2d distributed so as to open at least on the first surface 2a and the side surface 2c. That is, the first surface 2a and the side surface 2c are connected via the voids 2d within the substrate 2. For example, the voids 2d have a structure in which the voids enter the substrate 2 from one inlet (opening) on ​​the first surface 2a or the side surface 2c and branch into multiple paths, or a structure in which the voids enter the substrate 2 from multiple inlets (openings) on the first surface 2a or the side surface 2c and merge into one path. In this embodiment, the voids 2d are irregularly distributed within the substrate 2. That is, the voids 2d have a structure different from a regular structure formed by multiple pores extending in a specific direction. As an example, the substrate 2 is formed by a plurality of particles 20 connected to each other, and the voids 2d are formed by the spaces between adjacent particles 20.

[0029] An example of the substrate 2 is a structure in which a plurality of particles 20 are bonded or adhered to one another. For example, the plurality of particles 20 are bonded to one another by fusion so as to maintain contact and connection with one another. The diameter of the particles 20 is, for example, approximately several tens of μm. The shape or size (diameter) of each particle 20 may vary slightly. In this embodiment, the particles 20 are formed from an insulating material. As an example, the particles 20 are formed from glass, ceramic, or the like. From the viewpoint of facilitating the production of a structure in which a plurality of particles 20 are bonded by fusion, soda glass, which has a relatively low melting point among glasses, may be used as the material for the particles 20. Furthermore, the particles 20 are formed in an approximately spherical shape. An example of such approximately spherical particles 20 is glass beads.

[0030] 3 and 5, the first surface 2a is composed of surfaces 21 on one side of a plurality of particles 20A that are located in the outermost layer on one side in the Z-axis direction among the plurality of particles 20. Note that Fig. 5 is an SEM image of the first surface 2a (partial region A as shown in Fig. 1) of the substrate 2 in a state before the conductive layer 3 is provided. In this embodiment, the surfaces 21 of the particles 20A that make up the first surface 2a are smooth (non-rough), unlike the outer surfaces (rough surfaces 21a) of the lateral particles 20B described below.

[0031] As shown in Figures 4 and 6, the side surface 2c is composed of the outer surfaces (surfaces facing outward when viewed from the Z-axis direction) of multiple lateral particles 20B located in the outermost layer in the X-axis direction or the Y-axis direction among the multiple particles 20. The particles located in the outermost layer on one side in the Z-axis direction among the multiple lateral particles 20B also correspond to the above-mentioned particles 20A. Note that Figure 6 is an SEM image of the side surface 2c (partial region B as shown in Figure 1) of the substrate 2 in a state before the conductive layer 3 is provided. At least a portion of the outer surfaces of the multiple lateral particles 20B are rough surfaces 21a including a fine uneven structure 4. For example, the uneven structure 4 can be composed of multiple (pointed) convex portions 4a protruding outward and multiple concave portions 4b recessed inward. The multiple convex portions 4a and the multiple concave portions 4b may be formed regularly or irregularly. It should be noted that the uneven structure 4 in this embodiment is a structure formed on one particle 20 itself, and is not an uneven structure that occurs when multiple particles 20 are arranged adjacent to each other (for example, an uneven structure in which the grooves between adjacent particles 20 are regarded as recesses).

[0032] The rough surface 21a can be formed by various known roughening processes for roughening the outer surface of the lateral particle 20B. Examples of roughening processes include sandblasting, laser processing, etching (dry etching), and molding using a mold. As an example, the substrate 2 can be formed by cutting a base substrate (a porous substrate having a larger area than the substrate 2 when viewed from the Z-axis direction) formed by an aggregate of multiple particles 20. However, the rough surface 21a may also be formed during a cutting process in which the base substrate is cut using a cutting method such as blade dicing, water jet processing, or laser cutting. The base substrate described above is, for example, a sintered body of multiple particles 20. As an example, the multiple particles 20 are compressed using a press or the like and then heated at a high temperature below the melting point of the particles 20, thereby fusing the surfaces of the multiple particles 20 together and obtaining a sintered body (base substrate) made of the multiple particles 20. In this embodiment, the particles 20 are formed from an insulating material, and therefore the base substrate has insulating properties.

[0033] 4, side particle 20B has a non-rough surface 21b on the side opposite to rough surface 21a, where uneven structure 4 is not formed. That is, the outer surface of side particle 20B is roughened surface 21a as described above, but the inner surface of side particle 20B is a smooth surface (non-rough surface 21b) similar to surface 21 of particle 20A that constitutes first surface 2a.

[0034] The conductive layer 3 is provided on the surface of the substrate 2. As shown in FIGS. 1 and 2, in this embodiment, the conductive layer 3 is provided so as to cover the first surface 2a and the side surface 2c. In other words, by covering the first surface 2a and the side surface 2c of the substrate 2 formed from the insulating base substrate as described above with the conductive layer 3 to make them conductive, a structure is realized in which a specific voltage can be applied to the first surface 2a and the side surface 2c of the substrate 2. Furthermore, the conductive layer 3 is not provided in the portions corresponding to the four corners of the first surface 2a. In other words, the conductive layer 3 is not provided in the four corners of the first surface 2a, and regions in which the first surface 2a (surface 21 of the particles 20A) of the substrate 2 is exposed are provided. In other words, almost the entire surface of the first surface 2a except for the portions corresponding to the four corners is covered with the conductive layer 3. Furthermore, the side surface 2c covered with the conductive layer 3 is arranged so as to surround the first surface 2a covered with the conductive layer 3, and the conductive layer 3 on the first surface 2a and the conductive layer 3 on the side surface 2c are electrically connected. As a result, almost the entire first surface 2a is at the same potential, and the side surfaces 2c surrounding the first surface 2a are also at the same potential as the first surface 2a, so the potential of the first surface 2a can be stabilized.

[0035] 3, the conductive layer 3 has a first conductive region 31 provided on the first surface 2a so as not to block the opening of the void 2d on the first surface 2a. For example, the first conductive region 31 is formed along the surface 21 of each particle 20A so as not to completely cover the opening of the void 2d on the first surface 2a. That is, the first conductive region 31 is formed continuously on the first surface 2a of each particle 20A, but is provided so as not to block the void 2d when viewed from the Z-axis direction. This allows a portion of the sample S transferred to the first surface 2a (e.g., excess liquid components) to penetrate into the substrate 2.

[0036] As shown in FIG. 4 , the conductive layer 3 has a second conductive region 32 provided on the side surface 2c so as not to block the opening of the void 2d on the side surface 2c. For example, the second conductive region 32 is formed along the surface (rough surface 21a) of each lateral particle 20B, and is therefore provided so as not to completely cover the opening of the void 2d on the side surface 2c. That is, the second conductive region 32 is formed continuously on the surface of each lateral particle 20B, but is provided so as not to block the void 2d when viewed from the X-axis or Y-axis direction. The second conductive region 32 is connected to the first conductive region 31. That is, the second conductive region 32 is formed continuously with the first conductive region 31. The second conductive region 32 is provided on the rough surface 21a of multiple lateral particles 20B, following the surface shape of the uneven structure 4. That is, the thickness of the second conductive region 32 is made very thin compared to the size (diameter) of the lateral particle 20B. As a result, the shape of the outer surface of the conductive layer 3 formed on the surface of the lateral particle 20B follows the surface shape (uneven shape) of the uneven structure 4. Therefore, as shown in Fig. 4, even after the conductive layer 3 is formed, the uneven shape of the side surface 2c (i.e., the uneven shape of the rough surface 21a of each lateral particle 20B) is maintained.

[0037] The conductive layer 3 is formed of a conductive material. It is preferable that the material of the conductive layer 3 be a metal that has low affinity (reactivity) with the sample to be analyzed and high conductivity. From this perspective, it is preferable that the material of the conductive layer 3 be, for example, gold (Au), platinum (Pt), or the like. The conductive layer 3 is formed to a thickness of approximately 1 nm to 350 nm by, for example, a plating method, atomic layer deposition (ALD), vapor deposition, sputtering, or the like. It should be noted that the material of the conductive layer 3 may also be, for example, chromium (Cr), nickel (Ni), titanium (Ti), or the like.

[0038] The conductive layer 3 is formed of a conductive material. It is preferable to use a metal that has low affinity (reactivity) with the sample and high conductivity as the material for the conductive layer 3. From this perspective, it is preferable to use, for example, Au (gold), Pt (platinum), etc. as the material for the conductive layer 3. The conductive layer 3 is formed to a thickness of approximately 1 nm to 350 nm by, for example, a plating method, an atomic layer deposition (ALD), a vapor deposition method, a sputtering method, etc. Note that, for example, Cr (chromium), Ni (nickel), Ti (titanium), etc. may also be used as the material for the conductive layer 3.

[0039] [Mass spectrometry method] An example of a mass spectrometry method using a sample support 1 (a method using laser desorption ionization) will be described. With reference to Figures 7 and 8, a mass spectrometry method using an example of a mass spectrometer (mass spectrometer 10) will be described. First, the sample support 1 is prepared (first step). Next, a sample S is placed (transferred) on a first surface 2a of a substrate 2 (second step). The sample S is, for example, a slice of fruit (such as a strawberry). For example, the sample S is pressed against the first surface 2a of the substrate 2, thereby adhering the sample S (a part of the sample S) to the first surface 2a.

[0040] Subsequently, after the sample S is attached to the first surface 2a, the components (molecules) of the sample S are ionized by irradiating the first surface 2a with an energy beam while applying a voltage to the first surface 2a (conductive layer 3) (step 3). The above-described step 3 can be performed, for example, by using a mass spectrometer 10 shown in Fig. 8. The mass spectrometer 10 includes a support unit 12, an irradiation unit 13, a voltage application unit 14, an ion detection unit 15, a camera 16, a control unit 17, and a sample stage 18.

[0041] As shown in FIGS. 7 and 8 , for example, the sample support 1 is fixed to the support substrate 8 via conductive tape 9, with the second surface 2b of the substrate 2 placed on the support surface 8a of the support substrate 8. With the sample support 1 fixed to the support substrate 8 in this manner, the support substrate 8 is placed on the support portion 12. As shown in FIG. 7 , for example, the conductive tape 9 is provided at the center of both side edges in the longitudinal direction (X-axis direction) of the substrate 2 in the short direction (Y-axis direction), and is arranged over a portion of the first conductive region 31 on the first surface 2a, a portion of the second conductive region 32 on the side surface 2c, and the support surface 8a of the support substrate 8. As a result, the conductive layer 3 is electrically connected to the support surface 8a of the support substrate 8 via the conductive tape 9. The support substrate 8 is, for example, a slide glass. For example, the support substrate 8 is a glass substrate (ITO slide glass) on which a transparent conductive film such as an ITO (indium tin oxide) film is formed, and the surface of the transparent conductive film serves as the support surface 8a. That is, in this embodiment, the entire support surface 8a is electrically conductive.

[0042] The irradiation unit 13 irradiates the first surface 2a of the sample support 1 with an energy beam such as laser light L. The voltage application unit 14 applies a voltage to the first surface 2a of the sample support 1. The ion detection unit 15 detects ionized sample components (sample ions SI). The camera 16 acquires a camera image including the position irradiated with the laser light L by the irradiation unit 13. The camera 16 is, for example, a small CCD camera attached to the irradiation unit 13. The control unit 17 controls the operations of the sample stage 18, the camera 16, the irradiation unit 13, the voltage application unit 14, and the ion detection unit 15. The control unit 17 is, for example, a computer device including a processor (for example, a CPU), a memory (for example, a ROM, a RAM), etc.

[0043] The voltage application unit 14 applies a voltage to the support surface 8 a of the support substrate 8. As a result, a voltage is applied to the conductive layer 3 via the support surface 8 a and the conductive tape 9. Next, the control unit 17 operates the irradiation unit 13 based on the camera image acquired by the camera 16. Specifically, the control unit 17 operates the irradiation unit 13 so that the laser light L is irradiated onto the laser irradiation range (for example, the entire substrate 2 identified based on the camera image).

[0044] As an example, the control unit 17 moves the sample stage 18 and controls the irradiation operation (e.g., irradiation timing) of the laser light L by the irradiation unit 13. That is, the control unit 17 confirms that the sample stage 18 has moved a predetermined distance, and then causes the irradiation unit 13 to irradiate the laser light L. For example, the control unit 17 repeats the movement (scanning) of the sample stage 18 and the irradiation of the laser light L by the irradiation unit 13 so as to raster scan the laser irradiation range. Note that the irradiation position on the first surface 2a may be changed by moving the irradiation unit 13 instead of the sample stage 18, or by moving both the sample stage 18 and the irradiation unit 13.

[0045] In the third step described above, the components of the sample S on the first surface 2a are ionized, and sample ions SI are emitted. Specifically, energy is transferred from the conductive layer 3 that has absorbed the energy of the laser light L to the components of the sample S on the first surface 2a, and the components that have acquired the energy vaporize and acquire an electric charge, becoming sample ions SI. The emitted sample ions SI move while accelerating toward a ground electrode (not shown) provided between the sample support 1 and the ion detection unit 15. In other words, the sample ions SI move while accelerating toward the ground electrode due to the potential difference generated between the conductive layer 3 to which a voltage is applied and the ground electrode. The sample ions SI are then detected by the ion detection unit 15 (fourth step).

[0046] The above-described first to third steps correspond to an ionization method using the sample support 1. The above-described first to fourth steps correspond to a mass spectrometry method using the sample support 1. Furthermore, by mapping the intensities of the sample ions SI detected in the fourth step for each irradiation position of the laser light L, an MSI image showing the two-dimensional distribution of sample molecules can be obtained. This allows mass spectrometry imaging (MSI) to be performed.

[0047] 3 and 5, in the sample support 1, the substrate 2 includes a gap 2d that opens to the first surface 2a. As a result, when the sample S is introduced to the first surface 2a of the substrate 2 (in this embodiment, the first conductive region 31 on the first surface 2a; the same applies below), the sample S diffuses appropriately into the gap 2d of the substrate 2, and the amount of sample S remaining on the first surface 2a is appropriately adjusted. As a result, the sample S remaining on the first surface 2a can be suitably ionized.

[0048] As shown in FIGS. 4 and 6 , the gap 2d of the substrate 2 also opens to the side surface 2c. That is, the first surface 2a and the side surface 2c are connected via the gap 2d inside the substrate 2. This allows for convenient degassing of the substrate 2 (i.e., discharging gas accumulated in the gap 2d from the side surface 2c) when, for example, the sample support 1 with the sample S transferred to the first surface 2a of the sample support 1 is introduced into a vacuum device (part of the mass spectrometer 10 described above). That is, as shown in FIG. 9A , the side surface 2c is not blocked, so that gas accumulated inside the substrate 2 can be discharged to the outside from the side surface 2c, thereby improving the speed of the degassing operation (vacuum attainment speed). Furthermore, because gas is less likely to remain inside the substrate 2, it is possible to prevent residual gas from interfering with the detection of sample ions SI by the ion detection unit 15 in the above-mentioned ionization step (third step).

[0049] Furthermore, as shown in FIG. 9B , even when transferring the sample S to the entire first surface 2a, gas introduced into the substrate 2 from the first surface 2a can escape through the opening in the side surface 2c. This prevents excess gas (residual gas) from accumulating inside the substrate 2, thereby preventing uneven transfer due to the residual gas. Additionally, as shown in FIG. 9B , during the transfer of the sample S, the second surface 2b may not be exposed to the outside because a protective tape T or the like is provided on the second surface 2b. Therefore, even if the void 2d inside the substrate 2 is connected from the first surface 2a to the second surface 2b, if the side surface 2c is blocked, there is no escape route for the gas introduced into the substrate 2 from the first surface 2a during transfer. In contrast, in the sample support 1, the void 2d is configured to also open to the side surface 2c as described above, so that gas can be efficiently vented during transfer even when transferring the sample S to the entire first surface 2a. Furthermore, when multiple sample supports 1 are used arranged in the X-axis or Y-axis direction (for example, when the size of the sample S to be analyzed does not fit within the measurement surface (first surface 2a) of one sample support 1), the side surface 2c of the substrate 2 of each sample support 1 is open, so that the continuity of adjacent sample supports 1 (substrate 2) can be maintained.

[0050] Furthermore, at least a portion of the outer surface of the side surface 2c of the substrate 2 is made into a rough surface 21a on which an uneven structure 4 is formed. As a result, for example, when an operator holds the side surface 2c of the substrate 2 with his / her fingers or when holding the side surface of the substrate 2 using a tool for supporting the sample support 1, the rough surface 21a (uneven structure 4) exhibits a non-slip function, thereby improving the handleability of the sample support 1. As described above, the sample support 1 can achieve high-precision analysis and also improve handleability.

[0051] As shown in Figure 4, lateral particle 20B has a non-rough surface 21b on the side opposite to rough surface 21a, where no uneven structure 4 is formed. By making the inner surface of lateral particle 20B a non-rough surface 21b, the bonding strength between lateral particle 20B and the particles 20 located inside lateral particle 20B is sufficiently ensured, and spillage of lateral particle 20B can be suppressed. Furthermore, by not providing an uneven structure 4 on the inside of lateral particle 20B, the flow of gas inside lateral particle 20B (for example, the flow of residual gas described above) can be made smoother compared to when an uneven structure 4 is formed inside lateral particle 20B, and thus gas can be preferably vented through the opening in side surface 2c.

[0052] A substance (hereinafter referred to as the "specific substance") that emits ions in response to irradiation with laser light L is disposed on the roughened surface 21 a of the lateral particle 20B. Examples of the specific substance include a metal film and a light-absorbing substance (e.g., an organic material or dye that absorbs ultraviolet light). In this embodiment, as shown in FIG. 4 , a conductive layer 3 (second conductive region 32) is disposed on the roughened surface 21 a. The conductive layer 3 is a metal film, and therefore corresponds to the specific substance. According to the sample support 1, the entire first surface 2 a of the sample support 1 (the entire surface including the side surface 2 c when viewed from the Z-axis direction) is irradiated with laser light L to ionize components (molecules) of the sample S present on the first surface 2 a. Mass spectrometry imaging (MSI) is then performed to two-dimensionally visualize the spatial distribution of the ionized components. In the resulting imaging result (the above-described MSI image), the portion corresponding to the side surface 2 c of the substrate 2 (i.e., the outer edge of the sample support 1) can be clearly identified. More specifically, since the rough surface 21 a has the uneven structure 4 (edge ​​structure), the energy of the laser light L is easily absorbed by the edge portion of the rough surface 21 a, which makes it easier for the components of the specific substance (in this embodiment, a part of the conductive layer 3 (second conductive region 32)) present on the surface of the edge portion to be suitably ionized and desorbed, thereby making it possible to easily and accurately identify the portion corresponding to the outer edge of the sample support 1 in the MSI image.

[0053] The above effect will be further explained with reference to FIG. 10 . In FIG. 10 , the overall image P is a portion of a camera image (scanned image) obtained by a camera (e.g., the camera 16 of the mass spectrometer 10 described above). Image P was obtained by arranging the sample support 100 of the comparative example and the sample support 1 of the example side by side on a predetermined support plate (a black plate having multiple grooves shown in the center of image P) and photographing a portion of one outer edge (a portion including the side surface 2c) of the comparative example and a portion of one outer edge (a portion including the side surface 2c) of the example. The sample support 100 of the comparative example differs from the sample support 1 in that the outer surface of the lateral particle 20B is a smooth surface similar to the surface 21 of the particle 20A (i.e., the rough surface 21a like the lateral particle 20B of the sample support 1 is not formed).

[0054] In Figure 10, partial images P1 and P2 superimposed on image P show imaging results (portions of MSI images) at corresponding locations. Image P1 shows a portion of the MSI image of a portion including the outer edge (side surface 2c) of the comparative example (sample support 100). Image P2 shows a portion of the MSI image of a portion including the outer edge (side surface 2c) of the example (sample support 1). As shown in images P1 and P2 in Figure 10, it was confirmed that the example (image P2) obtained a higher signal intensity at the outer edge (side surface 2c) of the sample support (substrate 2) than the comparative example (image P1). That is, by forming the outer surface of the lateral particle 20B into a rough surface 21a, it was confirmed that image P2, in which the outer edge of the sample support 1 is more clearly defined than image P1, can be obtained. This allows the position of the outer edge of the sample support 1 (the boundary line corresponding to side surface 2c) in the MSI image to be easily and accurately determined. As a result, for example, it becomes possible to easily and accurately align the camera image (image P) and the MSI image (images including image P2), thereby improving the accuracy of the analysis (mass spectrometry imaging).

[0055] As shown in FIG. 4 , the second conductive region 32 is provided on at least a portion of the roughened surface 21 a of the plurality of lateral particles 20B, following the surface shape of the concave-convex structure 4. For example, when ionizing components of the sample S remaining on the first surface 2 a by the laser desorption ionization method or the like as described above, it is necessary to apply a voltage to the conductive layer 3 (first conductive region 31) on the first surface 2 a. In order to stably apply a voltage to the first conductive region 31, it is preferable to also apply a voltage to the side surface 2 c, and it is preferable to provide the second conductive region 32 on the side surface 2 c. Furthermore, by providing the second conductive region 32 on at least a portion of the roughened surface 21 a of the plurality of lateral particles 20B, following the surface shape of the concave-convex structure 4, the above-mentioned effect (clarification of the outer edge of the sample support 1 in the MSI image) can be obtained. A possible configuration for applying a voltage to the first conductive region 31 is to place the sample support 1 on a conductive sample stage (support substrate 8 in this embodiment), connect the support substrate 8 to the conductive layer 3 of the sample support 1 with conductive tape 9, and apply a voltage to the conductive layer 3 via the support substrate 8 and the conductive tape 9. When adopting such a configuration for the sample support 1, the conductive tape 9 is provided so as to cover the conductive layer 3 on the rough surface 21 a of the lateral particle 20B (i.e., the portion of the second conductive region 32 having a surface shape similar to the uneven structure 4 of the rough surface 21 a of the lateral particle 20B), thereby enabling the uneven structure 4 to exert an anchoring effect and increasing the adhesive strength of the conductive tape 9 to the second conductive region 32. This allows a voltage to be applied to the conductive layer 3 stably and reliably.

[0056] The thickness (average thickness) of the conductive layer 3 in the second conductive region 32 may be smaller than the thickness (average thickness) of the conductive layer 3 in the first conductive region 31. For example, the amount (deposition amount) of the second conductive region 32 per unit area may be smaller than the amount (deposition amount) of the first conductive region 31 per unit area. For example, when the conductive layer 3 is formed by vapor deposition, the direction of vapor deposition on the first surface 2a may be different from the direction of vapor deposition on the side surface 2c, so that the thickness of the second conductive region 32 is smaller than the thickness of the first conductive region 31. According to the above configuration, by ensuring a constant thickness for the first conductive region 31 on the first surface 2a, a voltage can be stably applied to the first surface 2a during analysis. On the other hand, by reducing the thickness of the conductive layer 3 for the second conductive region 32 on the side surface 2c, the above-mentioned effects (i.e., improved adhesive strength of the conductive tape 9 to the second conductive region 32 due to the anchor effect and clarity of the outer edge of the sample support 1 in MSI images) can be more effectively obtained.

[0057] As shown in FIGS. 1 and 7 , the first surface 2 a of the substrate 2 has a rectangular shape, and the conductive layer 3 is not provided in the portions corresponding to the four corners of the first surface 2 a. In the present embodiment, as an example, triangular regions where the first surface 2 a is exposed are provided at the four corners of the first surface 2 a. By not providing the conductive layer 3 in the portions corresponding to the four corners of the first surface 2 a, it is easy to visually distinguish between the portions of the first surface 2 a where the conductive layer 3 is provided (i.e., the first conductive regions 31) and the portions corresponding to the four corners of the first surface 2 a. This makes it possible to easily align the sample stage 18 of the mass spectrometer 10 by using the portions corresponding to the four corners of the first surface 2 a as markers.

[0058] As shown in Figures 2 and 8, the side surface 2c includes an inclined region that slopes outward from the first surface 2a toward the second surface 2b. This configuration improves the stability of the sample support 1 when it is placed on a sample stage or the like (in this embodiment, a support substrate 8) during analysis. Furthermore, when the conductive tape 9 described above is provided to cover the edge of the first surface 2a, the inclined region of the side surface 2c, and the upper surface (support surface 8a) of the support substrate 8, the adhesion between the conductive tape 9 and the sample support 1 can be improved. This prevents gaps from forming between the conductive tape 9 and the side surface 2c and support surface 8a of the sample support 1, thereby stably fixing the sample support 1 to the support surface 8a and preventing the conductive tape 9 from peeling off. Furthermore, by inclining the side surface 2c as described above, the laser light L can be more easily incident on the rough surface 21a of the side particle 20B in the above-described laser desorption ionization method, and therefore the effect described with reference to FIG. 10 (i.e., clarification of the outer edge of the sample support 1 in the MSI image) can be more effectively obtained.

[0059] [Modifications] The present disclosure is not limited to the above-described embodiment. The materials and shapes of each component are not limited to those described above, and various materials and shapes can be used. Furthermore, some components included in the sample support 1 according to the above embodiment may be omitted or modified as appropriate. For example, the above embodiment describes several characteristic components included in the sample support 1 and several effects achieved by each component. However, the sample support according to the present disclosure does not necessarily need to be configured to achieve all of the effects described in the above embodiment, and may be configured to achieve only some of the effects described in the above embodiment. In the latter case, the sample support only needs to include components essential for achieving at least some of the effects, and components that are not essential for achieving those effects may be omitted or modified as appropriate. Below, several modifications of the sample support according to the present disclosure are illustrated.

[0060] In the above embodiment, glass, ceramic, etc. are exemplified as materials for the particles 20. However, the particles 20 may be formed of a conductive material (e.g., a metal such as aluminum). In this case, the conductive layer 3 in the above embodiment can be omitted.

[0061] In the above embodiment, the ionization method is based on laser desorption ionization, and therefore the conductive layer 3 is provided on the surface of the insulating substrate 2 to impart electrical conductivity to the sample support 1. However, if electrical conductivity is not required for the sample support 1 (or if electrical insulation is required), the conductive layer 3 may be omitted. In this case, the sample support 1 can be used for desorption electrospray ionization (DESI), in which charged microdroplets are irradiated onto the first surface 2 a of the substrate 2.

[0062] In the above embodiment, the substrate 2 is formed of an aggregate of a plurality of particles 20 (sintered glass beads) as shown in Figures 5 and 6, and therefore the voids 2d are open to the first surface 2a and the side surface 2c, as well as to the second surface 2b. However, the voids 2d do not have to be open to the second surface 2b. For example, the substrate 2 may be formed of a flat plate including the second surface 2b and a porous structure (i.e., a plurality of particles 20) provided on the surface of the plate opposite to the second surface 2b. As an example, the substrate 2 may be formed of a glass plate and a porous structure provided on the glass plate.

[0063] In the above embodiment, as shown in Figure 6, the outer surfaces of substantially the entire area of ​​the side particles 20B constituting the side surface 2c (the outermost surface when viewed from the Z-axis direction) are roughened surfaces 21a including the uneven structure 4, but the outer surfaces of substantially the entire area of ​​the side particles 20B do not necessarily have to be roughened surfaces 21a. That is, it is sufficient that the outer surfaces of at least a portion of the multiple side particles 20B constituting the side surface 2c are roughened surfaces 21a. For example, only the outer surfaces of the side particles 20B belonging to a portion of the side surface 2c on the first surface 2a side (a portion of the region continuous with the first surface 2a) may be roughened surfaces 21a.

[0064] In the above embodiment, as shown in Fig. 2, the entire side surface 2c is formed as an inclined region that slopes outward from the first surface 2a toward the second surface 2b. However, only a portion of the side surface 2c (e.g., a portion of the side connected to the first surface 2a) may be inclined. It is not essential that the side surface 2c include an inclined region. For example, the side surface 2c may be formed to extend along a direction (Z-axis direction) perpendicular to the first surface 2a and the second surface 2b.

[0065] In the above embodiment, the conductive layer 3 continuously provided on the first surface 2a and the side surface 2c was used as the specific substance. However, in cases where the conductive layer 3 itself is omitted as described above, a specific substance different from the conductive layer 3 may be disposed (e.g., formed as a film) on the rough surface 21a for the sole purpose of achieving the effect described with reference to FIG. 10 (clarification of the outer edge of the sample support 1 in the MSI image). Alternatively, at least a portion of the multiple lateral particles 20B (e.g., the lateral particles 20B themselves) may be formed of a specific substance. In this case, the lateral particles 20B themselves are ionized. This configuration also allows for the acquisition of an MSI image in which the outer edge of the sample support 1 is clearly defined.

[0066] The shape of the particles 20 is not limited to being approximately spherical, and may have a shape other than approximately spherical.

[0067] In the above embodiment, an example was shown in which the sample support 1 is used in a mass spectrometry method, but the sample support 1 can be used for various analytical purposes other than mass spectrometry, including sample ionization. Furthermore, the use of the sample support 1 is not limited to ionizing a sample by irradiation with laser light L, such as the laser desorption ionization method shown in the above embodiment. The sample support 1 can also be used to ionize a sample by irradiation with an energy beam other than laser light. For example, the sample support 1 can also be used to ionize a sample by irradiation with an energy beam such as electrospray, an ion beam, or an electron beam. In the above-described ionization method and mass spectrometry method, the sample can be ionized by irradiation with such an energy beam.

[0068] 1...sample support, 2...substrate (porous substrate), 2a...first surface, 2b...second surface, 2c...side surface, 2d...void, 3...conductive layer, 4...uneven structure, 20, 20A...particles, 20B...side particles, 21...surface, 21a...rough surface, 21b...non-rough surface, 31...first conductive region, 32...second conductive region, L...laser light (energy ray), S...sample.

Claims

1. A sample support for ionizing a sample, comprising a porous substrate having a first surface, a second surface opposite to the first surface, a side surface connecting an edge of the first surface with an edge of the second surface, and voids distributed so as to open onto at least the first surface and the side surface, wherein the porous substrate is formed from a plurality of particles connected to each other, and at least a portion of the outer surfaces of a plurality of side particles constituting the side surface among the plurality of particles are roughened with an uneven structure formed thereon.

2. A sample support as described in claim 1, wherein at least a portion of the plurality of side grains have a non-rough surface on the side opposite to the rough surface on which the uneven structure is not formed.

3. A sample support according to claim 1 or 2, wherein at least a portion of said plurality of side particles are formed from a material that emits ions in response to irradiation with an energy beam.

4. A sample support according to any one of claims 1 to 3, wherein a substance that releases ions in response to irradiation with an energy beam is disposed on the rough surfaces of at least a portion of the plurality of side grains.

5. A sample support as described in any one of claims 1 to 4, further comprising a conductive layer provided on the surface of the porous substrate, the conductive layer including a first conductive region provided on the first surface so as not to block the openings of the voids in the first surface, and a second conductive region connected to the first conductive region and provided on the side surface so as not to block the openings of the voids in the side surface, the second conductive region being provided along the surface shape of the uneven structure on the rough surfaces of at least a portion of the plurality of side particles.

6. The sample support of claim 5, wherein the thickness of said conductive layer in said second conductive region is less than the thickness of said conductive layer in said first conductive region.

7. A sample support according to claim 5 or 6, wherein the first surface has a rectangular shape, and the conductive layer is not provided in portions corresponding to the four corners of the first surface.

8. A sample support according to any one of claims 1 to 7, wherein the side surface includes a sloping region that slopes outwardly from the first surface towards the second surface.

Images