JP2007192673A - Sample plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sample plate being a functional sample plate which has a sample fixed to its surface and ionizes the sample by applying energy to the sample, simplified in manufacturing process and flexibly altered in its constitution. <P>SOLUTION: The sample plate 1 is constituted by joining a functional plate 2 having a porous layer 4 formed to the whole surface of its one side by anodizing treatment and a mask plate 3 wherein a plurality of opening parts 31 are formed to a metal sheet. Conventionally, processes for resist coating→exposure→the etching of the opening parts→anodizing treatment→the removal of a resist are required in order to form the spot like well for fixing the sample but, since one anodizing treatment process to the whole surface may be performed, this sample plate is advantageous from an aspect of a manufacturing process, a working time, and a process cost. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sample plate for holding a sample to be analyzed (sample). In particular, the present invention is used as a sample plate that is ionized and released into an atmosphere by applying energy to the held sample. In particular, it is suitably used as a sample plate used for desorption / ionization on silicon (DIOS) or surface-assisted laser desorption / ionization (SALDI).

  In the fields of clinical and biochemistry, mass spectrometers are frequently used to perform qualitative or quantitative analysis on samples such as proteins. In this method, analysis is performed from a mass spectrum obtained by performing physical filtering using the mass (m) and the number of charges (z) of ions generated by applying energy to a sample. A time-of-flight mass spectrometer (TOFMS) that performs qualitative / quantitative analysis using the time from the ion generator to the detector is known.

FIG. 1 shows a general configuration example of a time-of-flight mass spectrometer.
The apparatus is roughly composed of an ion generation part 5 and a drift part 6, and these rooms are kept at a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁵ Pa. The sample to be analyzed is held on the sample plate 2. When energy is applied to the sample plate 2 by an appropriate method such as irradiating an energy beam such as a laser beam from the light source 8, the sample is ionized and gasified due to the ablation phenomenon. Released into the phase. When an appropriate voltage is applied between the sample plate 2 and the repeller electrode 9, the generated ions having various mass numbers are drawn into the drift portion 6 after being given the same energy. At this time, if the potential difference between the sample plate 2 and the repeller electrode 9 is E, the energy given to the charge q is qE. Therefore, when all of this is converted into kinetic energy, the following relationship is established.

qE = 1/2 · m · v ² Formula (1)

  Therefore, as shown in FIG. 2, the ion having a smaller molecular weight m has a higher velocity v, so that it reaches the detector 10 in a shorter time than an ion having a larger m. The time-of-flight mass spectrometer uses this arrival time difference to perform qualitative and quantitative analysis of the sample.

  In such an analysis method, particularly when analyzing a biological material such as a protein or a sample having a large molecular weight such as a polymer, the sample is mixed with an organic compound called a matrix and held on a sample plate, and energy is stored in the sample plate. A MALDI (Matrix Assisted Laser Desorption / Ionization) method in which mass analysis is performed by desorbing and ionizing a sample by irradiating a beam is generally known.

  On the other hand, a method for ionizing a sample without adding a matrix has been devised and put into practical use. A typical example is the DIOS method (Desorption / Ionization on (porous) Silicon: Patent Document 1). In this ionization method, the ionization ability of the sample is added to the sample plate itself, and by performing anodizing treatment (anodizing treatment: a kind of electrochemical anodizing method) on the surface of the Si substrate, A submicron-order porous part formed as a well is used as a sample plate. Moreover, although the name of DIOS is derived from Si as a base material, it has been reported that the same effect can be obtained even by the SALDI method using a material other than Si as a base material (Non-Patent Documents 1 and 2). ).

  In these methods, the sample is dropped and dried in the porous part and held, and is ionized by laser irradiation, etc., but compared with MALDI using a matrix, the dropped and dried sample can be seen with DIOS and SALDI. This is disadvantageous in that it is difficult to determine the sample position during laser irradiation. Therefore, in order to clarify the dropping position of the sample, the porous portion is formed as a well 22 that is a partial spot on the surface of the Si substrate 21, as shown in FIG. The left figure of FIG. 3 is an enlarged sectional view of one well. Using such a plate, a sample dispersed in an appropriate dispersant is dropped onto the well 22 and dried, and then the sample is ionized by performing laser irradiation using the well 22 as a target area (non-patent document). Reference 4).

US Pat. No. 6,288,390

JP 2004-361405 A

JP 2004-163142 A

Bull.Koream Chem.Soc.2002, Vol.23, No.2 315-319 (Reference: http://66.102.7.104/search?q=cache:mu-nxZU1HioJ:newjournal.kcsnet.or.kr/main/ j_search / j_download.htm% 3Fcode% 3DB020226 +% EF% BC% B3% EF% BC% A1% EF% BC% AC% EF% BC% A4% EF% BC% A9% E3% 80% 80mass & hl = en) http://www.mssj.jp/Japanese/Conference/2005/program_2005_C1_SY.html (1A-S1-02) Mei Han, Jan Sunner, J. Am. Soc. Mass Spectrom. 2000, 11, 644-649 http://www.waters.co.jp/product/column/massprep/dios_target.html

  However, as described above, in order to form the well 22 on the sample plate, it is necessary to first mask the substrate, then perform anodizing, and then remove the mask when forming the plate. There was a drawback that the plate manufacturing process was complicated.

  On the other hand, although a method of dropping a sample in a spot shape on an anodized whole surface of a base material without applying masking and drying it has been devised (Patent Document 2), the plate manufacturing process is extreme. However, since the sample diffuses as it is, it is necessary to adjust it to a paste (paragraph number 0029) or to drop the sample at a sufficient interval to prevent mixing with the adjacent sample. Come. If the drop interval is widened, the size of the plate is increased. If the drop interval is reduced, a separate manufacturing process such as forming a groove 50 is added as devised in MALDI (Patent Document 3, FIG. 1). Thus, contamination between adjacent samples must be prevented.

  Furthermore, in this type of analyzer, which is frequently used in clinical fields, generally, there are many cases of analyzing a small amount of samples of about several μ to ml, so that a large number of samples are held on one sample plate. There is a demand for it. Therefore, it is necessary to provide a spot for holding as many samples as possible on the sample plate and to easily grasp which sample is located at which position. Alternatively, automatic analysis having a function of moving a spot at an arbitrary coordinate on the sample plate to a laser irradiation position by an automatic device is desired. For this reason, the target spot on the sample plate always has regularity. It must be formed. In general, with DIOS or SALDI, it is difficult to see the dropped and dried sample, and it is difficult to determine the sample position during laser irradiation. Therefore, it is desirable to form the well 22 in order to clarify the dropping position of the sample. ing.

The present invention has been made in view of such technical problems and required specifications, and provides a sample plate that can hold a large number of specimens in close proximity without enlarging the entire plate and is easy to manufacture. To do.

  In order to achieve the above object, a sample plate according to the present invention includes a functional plate that is ionized by applying energy to a sample fixed to a surface, and an opening for fixing the sample fixed on the substrate. Having a mask plate.

  Moreover, the mass spectrometer which concerns on this invention is equipped with the said sample plate as a sample plate of an ionization part.

According to the above configuration, the spot (well) on which the sample on the functional plate is to be dropped is formed by the opening of the mask plate superimposed on the functional plate. It is only necessary to perform an additional process such as anodizing process on the entire lower surface of the opening arrangement part without going through multiple processes such as, and this can greatly reduce the plate manufacturing process and manufacturing time. it can. Further, by configuring the mask plate so as to be detachable from the functional plate, the opening can be made constant at all times, and the mass spectrometer can be easily automated in procedures such as sample dripping and ionization.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The mass spectrometer to which the sample plate according to the present invention is applied is not different from the conventional one in the overall configuration. For example, the time-of-flight mass spectrometer shown in FIG. 1 is roughly composed of an ion generation unit 5 and a drift unit 6, and these rooms have a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁵ Pa. It is kept. A sample such as protein, which is an analyte, is held on the sample plate 2, and when energy is applied to the sample plate 2 by an appropriate method such as irradiation with an energy beam such as infrared laser light, the sample is ionized. At the same time, it is released into the gas phase. When an appropriate voltage is applied between the sample plate 2 and the repeller electrode 9, the generated ions having various mass numbers are drawn into the drift portion 6 after being given the same energy. At this time, if the potential difference between the sample plate 2 and the repeller electrode 9 is E, the energy given to the electric charge q is qE. Therefore, when all of this is converted into kinetic energy, the relationship of the above-described equation (1) is established. . Accordingly, the ion having a smaller molecular weight m has a higher velocity v, so that an ion having a smaller m reaches the detector 10 in a shorter time. The time-of-flight mass spectrometer uses this arrival time difference to perform qualitative and quantitative analysis of the sample.

Here, a time-of-flight mass spectrometer is described as an example, but a time-separated type such as an ion trap mass spectrometer may of course be used. Further, it may be a multi-function machine whose main purpose is a function such as microscopic observation other than mass spectrometry, such as a microscopic analyzer. Application to a known technique using a sample plate is possible.

  In the present invention, the configuration of the sample plate used in such a mass spectrometer has the following characteristics. Although a sample plate for DIOS will be described as an example, it goes without saying that it can be applied to other types of functional sample plates such as SALDI.

  FIG. 6 is a structural example of a sample plate according to the present invention, which is a sample plate for DIOS having a sample ionization ability. As shown in FIG. 4, the entire surface of the Si substrate is subjected to anodizing treatment to form a porous layer 4 on the entire surface of one side of the substrate to form a functional plate 2. In the case of forming the well as shown in FIG. 3, the steps of resist coating → exposure → opening etching → anodizing process → resist removal are necessary. In the present invention, anodicizing to the entire surface is performed. Since only one processing step is required, it is advantageous in terms of manufacturing steps, work time, and manufacturing costs.

  Next, a mask plate according to the present invention is shown in FIG. The mask plate 3 has a plurality of openings 31 formed on a thin plate such as metal (for example, an aluminum thin plate having a thickness of 0.1 mm). The material of the thin plate is preferably a metal with little outgas when used in a vacuum, but is not particularly particular to ceramics or polymer materials as long as there is no problem in analysis. The opening 31 can be formed using a known processing means such as punching or grinding. The arrangement of the openings 31 is preferably in accordance with the automatic positioning coordinates of the sample of the mass spectrometer to be applied, but the shape and dimensions can be arbitrarily selected.

  The functional plate 2 shown in FIG. 4 and the mask plate 3 shown in FIG. 5 are overlapped to form the sample plate 1 according to the present invention shown in FIG. At the time of superposition, both plates may be completely joined, or they may be simply superposed with good adhesion. At the time of superposition, it is required that the sample dropped into the opening is liquid-tight so as not to leak into the adjacent opening.

  When joining, a well-known joining method can be employ | adopted with the material of each of a functional plate and a mask plate. For example, in the case of metals, welding, brazing, metal paste, adhesive, adhesive tape, etc. can be used. If both or one of the plates is a non-metallic material, a metal paste, an adhesive, an adhesive tape, etc. can be used.

  FIG. 7 shows an example in which a mechanical contact method in which the layers are stacked with good adhesion is adopted. A mask plate 3 having a width wider than that of the functional plate 2 is produced, and both ends of the mask plate 3 are bent and brought into contact with each other. Alternatively, after the plates 2 and 3 having the same size are overlapped as shown in FIG. 6, the periphery of the plates may be press-fixed with a fixture such as a frame. When the mechanical contact method is adopted, there is also an advantage that the sample plate can be disassembled after measurement and the mask plate can be reused.

  The configuration is not limited to the above-described embodiment, and the configuration can be modified within a range where the same effect can be achieved. For example, the porous layer 4 may be formed on the functional plate 2 leaving a blank in the upper portion or the like, and the mask plate 3 may be stacked so as to overlap the formation range of the porous layer 4.

  As described above, in the sample plate according to the present invention, the type of the functional plate is changed, the size and material of the mask plate, the size, shape, and number of the opening portions are different, and the specifications of the respective plates to be overlaid. By selecting arbitrarily, it is easy to produce a wide variety of sample plates. Moreover, the flexibility to the applied equipment is also good.

(Prototype example)
As the functional plate, a 43 × 23 × 0.5 mm Si substrate with anodizing treatment on the entire surface of one side was prepared. Further, a mask plate in which 4 × 8 openings having a diameter of 2 mm were formed on an Al thin plate having 43 × 23 × 0.1 mm was prepared. When these were bonded to each other with a conductive carbon double-sided tape for an electron microscope to form a sample plate and measured, good results could be obtained.

The sample plate according to the present invention is preferably used as a sample plate for a mass spectrometer, particularly for DIOS or SALDI, but can also be applied to an ionization method using a matrix-free ionization plate.

It is explanatory drawing which shows the general structural example of a time-of-flight mass spectrometer. It is explanatory drawing which shows the analysis principle of a time-of-flight mass spectrometer. It is explanatory drawing of the conventional sample plate. It is a figure which shows the example of preparation of the functional plate of the sample plate which concerns on this invention. It is a figure which shows the example of preparation of the mask plate of the sample plate which concerns on this invention. It is a figure which shows the example of preparation of the sample plate which concerns on this invention. It is a figure which shows the other example of preparation of the sample plate which concerns on this invention.

Explanation of symbols

1 ... sample plate 2 ... functional plate (conventional sample plate)
DESCRIPTION OF SYMBOLS 3 ... Mask plate 4 ... Porous layer 5 ... Ion generation part 6 ... Drift part 8 ... Laser light source 9 ... Repeller electrode 10 ... Detector

Claims (3)

A functional plate having a function of ionizing by applying energy to the sample fixed to the surface;
A mask plate having a plurality of openings for fixing the sample;
Sample plate that is liquid-tightly stacked.
The sample plate according to claim 1, which has a function of DIOS or SALDI.
A mass spectrometer comprising the sample plate according to claim 1 as a sample plate.

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