JP2000100375A - Mass spectrometer and electrostatic lens therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid chromatograph-mass spectrometer for analyzing a biological sample or the like, generating little noise, having high sensitivity and capable of stable operation over a long time. SOLUTION: In this means spectrometer, an ion capture port 19 for capturing ions into a mass analyzer part is positioned so as to be deviated from the center axis of an ion introduction fine aperture 15, and only ions are taken into a mass analyzer part 6 after being deflected with an electrostatic lens 21, thereby preventing a charged liquid drop from flowing into the mass analysis part 6. According to this construction, a charged liquid drop which becomes a noise source causes the sensitivity to drop in a mass spectrometer can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention is important for the separation and analysis of biologically related mixed samples such as sugars, peptides and proteins.
The present invention relates to an apparatus in which a separation means for a mixture is combined with a mass spectrometer, particularly to a liquid chromatograph / mass spectrometer and a capillary electrophoresis / mass spectrometer.

[0002]

2. Description of the Related Art At present, in the field of analysis, development of mass spectrometry for biological substances is regarded as important.

[0003] Since biological substances are usually dissolved in a solution as a mixture, an apparatus for combining a means for separating the mixture with a mass spectrometer has been developed. A typical apparatus for this method is a liquid chromatograph / mass spectrometer. Liquid chromatographs are excellent at separating mixtures but cannot identify substances, whereas mass spectrometers are sensitive and have excellent ability to identify substances, but the analysis of mixtures is difficult. Therefore, a liquid chromatograph / mass spectrometer using a mass spectrometer as a detector of the liquid chromatograph is very effective for analyzing a mixture. For reference, FIG. 20 is a block diagram showing the entire configuration of a conventional liquid chromatograph / mass spectrometer. The sample solution eluted from the liquid chromatograph 1 is introduced into an ion source 3 through a pipe 2.
The ion source 3 is controlled by a power source 4 for the ion source through a signal line 5a. The ions related to the sample molecules generated by the ion source 3 are introduced into the mass spectrometer 6 and subjected to mass analysis. The mass analyzer 6 is evacuated to a vacuum by an exhaust system 7. The mass-analyzed ions are detected by the ion detector 8, and the detection signal is sent to the data processing device 9 via the signal line 5b.

As described above, the principle of the liquid chromatograph / mass spectrometer is simple, but the liquid chromatograph handles a sample in a solution, whereas the mass spectrometer has a poor compatibility of handling ions in a vacuum. Therefore, development of this apparatus and method is very difficult. Several methods have been developed to solve this problem. Among them, a promising one is a spray ionization method in which an eluate from a liquid chromatograph is sprayed, and sample molecules contained in the generated droplets are ionized and taken into a mass spectrometer. As an example of the spray ionization method, Analytical Chemistry 1987, 59, 2642 (Analytical Chem.
istry, 59 , 2642 (1987)). FIG. 21 is a sectional view showing the structure of a liquid chromatograph / mass spectrometer provided with an electrostatic spray ion source. The sample solution eluted from the liquid chromatograph 1 is introduced into the spray capillary 11 via the pipe 2 and the connector 10. When a voltage of several kilovolts is applied between the spraying capillary 11 and the counter electrode 12, the so-called electrostatic spraying phenomenon occurs in which the sample solution has a cone shape at the tip of the spraying capillary 11 and microdroplets are generated from the tip. . In electrostatic spraying,
An atomizing gas ejection port 13 is provided, and a gas such as nitrogen is flowed from around the atomizing capillary 11 to promote the vaporization of the fine droplets. Further, a gas such as nitrogen is directed toward the generated microdroplets by a vaporizing gas outlet 14 provided on the counter electrode 12 side.
Spraying from the air to promote the vaporization of the microdroplets. The ions generated through the above-described process are transferred to the ion introduction pore 15
Is directly introduced into a vacuum 6 and mass analyzed by a mass spectrometer under a high vacuum. Further, in order to improve the S / N ratio in the mass spectrometer, the configuration shown in FIG. 22 has been used as the ion detector. An ion deflecting electrode 16 is provided at the rear of the mass analyzer 6 for mass separation by a high-frequency electric field, and deflects the mass-separated ions. The deflected ions are accelerated at a potential of several kilovolts, and bombard the secondary electron emission electrode 17 that emits secondary electrons. The secondary electrons thus obtained are detected by an electron detector 18 such as a seratron. With this configuration, neutral molecules or droplets having no charge are prevented from being detected as signals in the ion detector 8, and S / S
The N ratio is improved to some extent.

[0005]

The conventional method has the following problems. Ion-introducing pores for taking in ions
Not only ions but also charged droplets that are insufficiently vaporized are taken in. These charged droplets are too large and cannot be completely removed by a mass spectrometer that separates the mass by a high-frequency electric field. The charged droplets contaminate the mass spectrometer and prevent the mass spectrometer from operating stably for a long time, and are detected as noise in the ion detector, resulting in a poor signal-to-noise ratio (S / N ratio). And reduced the sensitivity of the mass spectrometer. In the configuration according to the prior art shown in FIG. 22 for improving the S / N ratio in the mass spectrometer, most of the charged droplets having electric charges are drawn out to the secondary electron emission electrode 17, which causes noise. . In addition, reduction of contamination of the mass spectrometer 6 has also been an issue. In order to remove the charged droplets as a source of the noise, the vaporization efficiency of the droplets in the ion source may be increased to completely eliminate the droplets.
However, if energy such as heat is applied to such an extent that the droplets can be completely vaporized, the easily-dissociated biomaterial may be denatured. The development of a method for introducing it to the mass spectrometry unit has been desired. An object of the present invention is to provide a mass spectrometer capable of performing stable analysis for a long time. Another object of the present invention is to provide a highly sensitive mass spectrometer with less noise.

[0006]

[Means for Solving the Problems] A mass spectrometer capable of performing stable analysis for a long time and having less noise by separating ions and charged droplets and selectively introducing only ions to the mass spectrometer. A means for separating a mixture of multi-component samples and impurities for each component, an ionization section for generating ions of sample molecules under atmospheric pressure, and an ion-introducing pore for introducing the generated ions into a vacuum. And a mass spectrometer having a mass spectrometer for mass spectrometric analysis of the introduced ions by means of a high-frequency electric field, wherein the ion inlet for taking ions into the mass spectrometer is displaced from the central axis of the ion introduction pore. This prevents the charged droplets from flowing into the mass spectrometer. More specifically, an electrostatic lens that deflects ions from the central axis of the ion introduction pore is provided to separate the trajectories of ions and charged droplets, and only ions are introduced into the mass spectrometer. As an example of the electrostatic lens that deflects the ions, an electrostatic lens that includes a cylindrical inner electrode and an outer electrode disposed outside the cylindrical inner electrode and has a plurality of openings in at least the inner electrode is provided.

[0007] Since the central axis of the ion introduction pore is displaced from the ion intake port of the mass spectrometer, huge charged droplets which are hardly affected by the electric field do not flow into the mass spectrometer. On the other hand, since an electrostatic lens for deflecting ions is provided, only ions can be efficiently introduced into the mass spectrometer. Therefore, contamination and noise due to liquid droplets in the mass spectrometry unit are reduced. The reduction of noise enables a highly sensitive mass spectrometer.

[0008]

1 to 19 show an embodiment of the present invention.
This will be described below. FIG. 1 shows the configuration of the apparatus according to the first embodiment of the present invention. The eluate sent from a means for separating a mixture in a solution such as a liquid chromatograph is introduced into the ion source 3. The ions related to the sample molecules generated by the ion source 3 are supplied to the ion introduction pore 15a and the exhaust system 7a.
Pressure part 33 and ion introduction pore 15 exhausted by
b into vacuum. In order to prevent so-called clustering, in which water molecules adhere to ions by cooling due to step thermal expansion when air or ions are introduced into a vacuum, the electrodes in which the ion introduction pores 15a and 15b are opened are heated by a heater. It is heated to about 100 ° C. The ion inlet 19 of the mass spectrometer 6 is arranged at a position deviated from the central axis of the ion introduction pores 15a and 15b. The ions taken into the vacuum are accelerated by an extraction electrode 20 composed of a single electrode or a plurality of electrodes, converged by an electrostatic lens 21, and then introduced into a quadrupole mass analyzer 6. The quadrupole mass spectrometer is usually housed in a metal cylinder 35 in order to avoid the influence of an external field, and the inside of the metal cylinder 35 is a high vacuum section 3 evacuated by the exhaust system 7b.
4. At this time, the electrostatic lens 21 is provided with an effect of deflecting the direction of ions, and only ions are introduced into the mass spectrometer 6 separately from the charged droplets. In the electrostatic lens 21 of FIG. 1, the solid line represents the trajectory of the ions, and the dotted line represents the trajectory of the charged droplet. The ions mass-separated by the high-frequency electric field in the mass analyzer 6 are detected by the ion detector 8. The configuration shown in FIG. 1 separates ions and droplets between the ion introduction pore and the mass spectrometer, so that the charged droplets are prevented from flowing into the mass spectrometer, and contamination and contamination of the mass spectrometer are prevented. Noise detected by the ion detector can be reduced. Hereinafter, the principle of separating charged droplets from ions will be described. The ions and charged droplets are accelerated to supersonic speed by the flow when they are taken into the vacuum from the ion introduction pore. Charged droplets having a larger mass than ions are less likely to be deflected by an electric field due to the kinetic energy obtained at this time, and have a trajectory along the central axis of the ion introduction pore. On the other hand, for light ions, the kinetic energy at the time of inflow is negligible compared to the acceleration energy given by the electric field of the extraction electrode, and the trajectory can be easily bent by the electric field. Due to this difference in kinetic energy when introduced from the ion introduction pore, it becomes possible to separate the trajectory between heavy charged droplets and light ions and selectively introduce only ions to the mass spectrometer. . In addition, in the embodiments described in FIGS. 1 to 7 and FIGS. 10 to 16, when the electrostatic lens 21 has an effect of drawing ions into the electrostatic lens by an electric field, the extraction electrode 20 may not be particularly provided. .

Various configurations are conceivable for realizing the electrostatic lens for deflecting the ions shown in FIG. 1. For example, a cylinder coaxially and multiplexed as described in JP-A-2-78143 is disclosed. FIG. 2 shows a configuration in which ions are deflected using an electrostatic lens composed of electrodes. Inner electrode 22
Are provided with a plurality of openings 23, through which the electric field of the outer electrode 24 penetrates into the inner electrode 22. This permeated electric field forms a potential distribution that converges the ions. When the central axis of the coaxial cylindrical electrostatic lens and the central axis of the ion introduction pore are shifted from each other, the ions are deflected, and in FIG.
Draw the trajectory indicated by the solid line. If the mass spectrometer 6 having the ion inlet 19 is disposed on the ion trajectory at the end of the electrostatic lens 21, the charged droplets can be discharged from the ion inlet 19.
Since this impinges on a portion other than the opening of the electrode 25 that is open, the entry into the mass spectrometer 6 is prevented, and only ions are taken into the mass spectrometer 6 through the ion inlet 19. At this time, it is desirable that the electrode 25 be heated by a heater or the like in order to reduce contamination of the electrode 25 where the ion intake port 19 is opened by the charged droplet.

The feature of the electrostatic lens shown in FIG. 2 is that deflection and convergence of ions can be achieved simultaneously with a single electrostatic lens composed of two cylindrical electrodes. In general, when creating an electrostatic lens portion, close attention is paid not only to processing accuracy of each electrode constituting the electrostatic lens but also to assembling accuracy of assembling each electrode at a predetermined position. This is because a slight shift in the arrangement of each electrode greatly changes the ion trajectory.

Therefore, it is desirable that the number of electrodes constituting the electrostatic lens be as small as possible. In order to deflect and converge ions, a complicated potential distribution must be formed in the electrostatic lens portion. Therefore, the number of electrodes tends to increase, and the structure tends to be complicated and the assembling workability tends to deteriorate. However, as shown in FIG. 2, a configuration is used in which an electrostatic lens composed of cylindrical electrodes coaxially and doubly assembled is used, and the central axis of the ion introduction pore and the central axis of the electrostatic lens are eccentrically arranged. When used, the electrostatic lens has two electrodes, so that an assembling workability is good and a device having a simple structure can be realized. An example of the dimensions of the electrostatic lens shown in FIG. 2 is shown for reference. The inner diameter of the inner electrode 22 is 20 mm, the inner diameter of the outer electrode 24 is 30 mm,
The axial length of the electrode is 15 cm, and the central axes of the ion introduction pores 15a and 15b and the ion inlet 1
Assuming that the degree of eccentricity with respect to the central axis of No. 9 is 4 mm, S /
The N ratio is increased by a factor of about 10 and thus the sensitivity in the mass spectrometer is improved by an order of magnitude. The inner diameter of the inner electrode is preferably about 3 mm to 10 cm, and the length of the electrode in the axial direction is preferably larger than the inner electrode inner diameter.

In order to easily and accurately construct an electrostatic lens for deflecting and converging ions, it is desirable to incorporate a cylindrical electrode coaxially as shown in FIG. It does not need to be constituted by one electrode, and as shown in FIG. 3, an independent plate-shaped outer electrode 24 may be arranged to face the outside of the opening 23 of the cylindrical inner electrode 22. When it is desired to further improve the degree of vacuum in the cylinder by increasing the exhaust conductance of the electrostatic lens unit, an opening 23 for exhaust may be provided in the outer electrode 24 as shown in FIG. When it is desired to further increase the exhaust efficiency, the outer electrode 24 may be formed of a metal mesh. In the case where the ion energy has dispersion and the dispersion of the energy becomes an aberration and the convergence effect of the electrostatic lens unit is lost, as shown in FIG.
A plurality of electrostatic lenses 21a and 21b are arranged, and an electrostatic lens 21 having a smaller inner diameter is provided at a rear portion of the first-stage electrostatic lens 21a.
b may be provided to enhance the convergence of ions.

FIG. 6 is a diagram showing a second embodiment of the present invention. When the central axes of the ion introduction pores 15a and 15b and the central axis of the cylindrical electrostatic lens 21 are arranged at an angle, the ions are transferred to the electrostatic lens 2 as shown by a solid line in the electrostatic lens 21.
1 is deflected in the axial direction and reaches the mass spectrometer 6, but the charged droplet collides with the inner wall surface of the electrostatic lens 21 as shown by a dotted line in the electrostatic lens 21, so that mass spectrometry is performed. Access to the part 6 is prevented. Further, as shown in FIG. 7, a curvature may be provided on the central axis of the cylindrical electrode constituting the electrostatic lens 21. In this case, similarly to the configuration shown in FIG. 6, the charged droplet goes straight and collides with the electrode, and only the ions reach the mass analyzer 6.

In order to easily form the electrodes constituting the lens, a pattern of a conductive thin film may be formed on the inner wall surface or the outer wall surface of the insulating tube. Further, a pattern of a conductive thin film may be formed on both the inner wall surface and the outer wall surface of the insulating tube, and these may be used as an inner electrode and an outer electrode, respectively. Further, a lens having a complicated shape as shown in FIG.
It may be formed using a conductive resin having conductivity and easily deformable.

The intensity of the electric field penetrating into the cylinder from the inner electrode is changed in the axial direction to accelerate or decelerate ions,
When it is desired to change the effect of convergence in the cylinder, the exhaust opening provided in the outer electrode may be changed in the axial direction. FIG. 8 shows a configuration for decelerating ions in the axial direction. As the opening area of the opening 23 opening to the outer electrode 24 is gradually reduced in the axial direction, the electric field strength penetrating into the cylinder of the inner electrode 22 changes in the axial direction, and the ions are decelerated.
Alternatively, different electric potentials may be applied to both ends of the outer electrode or the inner electrode, and the electric field strength penetrating into the cylinder may be changed in the axial direction by utilizing a potential drop at the outer electrode or the inner electrode. FIG. 9 shows a configuration in which a voltage is applied to both ends of the outer electrode 24 by the power supplies 4a and 4b, and the intensity gradient in the axial direction of the electric field penetrating into the cylinder of the inner electrode 22 is arbitrarily changed by a potential drop in the electrode portion. At this time, power supply 4
outer electrode 24 to which different voltages are applied according to a and 4b
Is preferably a material having resistance instead of metal in order to prevent excessive heat generation.

In the configuration described above, it is desirable that the electrostatic lens portion is heated by a heater or the like in order to reduce contamination of the electrostatic lens. Therefore, even in an electrostatic lens having a cylindrical inner electrode and an outer electrode arranged outside the cylindrical electrode, and having at least a plurality of openings in the inner electrode, at least one of the inner electrode and the outer electrode is heated by a heater or the like. It is desirable to keep. In addition, it is desirable that the electrode that opens the ion intake port that captures ions into the mass spectrometer is also heated.

FIG. 10 shows an example in which the present invention is applied to a so-called thermospray method in which a sample solution is heated and sprayed under reduced pressure. The eluate from the liquid chromatograph is introduced under reduced pressure, the tip of which is evacuated to several hundred pascals, and introduced into a spray capillary 11 heated to about 200 ° C. to be heated and sprayed. The ions related to the sample molecules that are statistically charged by the spraying are introduced into the mass spectrometer 6 evacuated to a high vacuum from the ion introduction pores 15 arranged in a direction perpendicular to the spraying direction. The ions introduced from the ion introduction pore are deflected by the electrostatic lens, taken into the quadrupole mass spectrometer, and subjected to mass analysis.

At this time, together with the ions, the ion introduction pores 15 are formed.
The introduced liquid droplet collides with the electrode 25 having the opening of the ion intake port 19, so that the liquid is prevented from flowing into the mass spectrometric unit 6.

FIG. 11 shows an example in which the present invention is applied to a mass spectrometer provided with multiple stages of mass spectrometers. The ions introduced into the vacuum from the ion introduction pores 15a and 15b are separated from the charged droplets by the electrostatic lens 21 and then introduced into the first stage mass spectrometer 6a where they are mass-separated and analyzed. Is sent to the collision chamber 26. In the collision chamber 26, ions and neutral gas collide, and so-called fragment ions, which are generated by fragmentation of the original ions, are obtained. This fragment ion is further introduced into the next mass spectrometer 6b and mass analyzed. Even in such a mass spectrometer having a plurality of mass spectrometers, it is effective to provide an electrostatic lens for deflecting ions between the ion introducing pore and the first mass spectrometer.

The means for separating the mixture is not limited to liquid chromatography, but may be capillary electrophoresis or supercritical fluid chromatography. FIG. 12 shows a configuration using a capillary electrophoresis apparatus as the separation means. A sample is introduced from one end of the capillary 27, a high voltage is applied between both ends of the capillary 27 by an electrophoresis power supply 28, and the capillary 27 is electrophoresed. The sample that has reached the end of the capillary 27 is introduced into the ion source 3 and ionized. The ions are introduced into the vacuum through the ion introduction holes 15a and 15b, are deflected by the electrostatic lens 21 (solid line shown in the electrostatic lens 21), and are mass-separated by the mass analyzer 6. At this time, the charged droplets originating from the buffer solution or the like are not deflected by the electric field of the electrostatic lens 21 (dotted line shown inside the electrostatic lens 21) and do not reach the mass spectrometry unit 6. Capillary electrophoresis includes capillary zone electrophoresis using a free solvent in the capillary, capillary gel electrophoresis in which a gel is filled in the capillary, micellar electrokinetic chromatography utilizing the difference in sample distribution into micelles, Various modes such as isokinetic-isoelectric focusing, in which a sample is introduced into the interface of a solvent containing ions having different mobilities and arranged in the order of the mobilities of the sample, have been proposed. Is effective regardless of the mode of the capillary electrophoresis.

Although different from a mass spectrometer for analyzing a mixture in a solution, the present invention is also effective for a mass spectrometer having an inductively coupled plasma ion source or a microwave plasma ion source. FIG. 13 shows the configuration. High-frequency electromagnetic waves such as microwaves obtained from the oscillating unit 29 are sent to the ion source 3 through the electric transmission path 30. A resonator is provided in the ion source 3, discharge occurs in the resonator, and a plasma state is generated. After the sample is introduced into the plasma and ionized, it is introduced into the vacuum through the ion introduction holes 15a and 15b. At this time, when photons such as ultraviolet rays obtained by the discharge reach the ion detecting section, they are detected as noise. However, only the ions are deflected by the electrostatic lens 21 (solid line shown in the electrostatic lens 21). The photons can be reached and go straight (dotted line shown in the electrostatic lens 21), collide with the electrode 25 with the opening of the ion intake port 19, and disappear.
Therefore, according to the present invention, the sensitivity of a mass spectrometer having an inductively coupled plasma ion source or a microwave plasma ion source can be improved.

The present invention is similarly effective in a mass spectrometer using a mass spectrometer other than the quadrupole type. FIG. 14 shows a configuration in which the present invention is used in a mass spectrometer having an ion trap type mass spectrometer. The ion trap type is a method in which ions are confined in a narrow space by a high-frequency electric field to perform analysis. As shown in FIG. 14, the ion trap portion is constituted by three electrodes, that is, two electrodes 31a and 31b called an end cap and a ring electrode 32 arranged so as to surround the periphery of the end cap. The ions taken into the vacuum from the ion introduction pores are deflected by the electrostatic lens 21 and guided into the ion trap through the end cap 31a where the ion intake port 19 opens. In the ion trap, ions are supplied to the end caps 31a, 3a.
The trajectory in the ion trap is controlled by the DC and AC electric fields given from the ring 1b and the ring electrode 32, and only ions having a specific mass are confined. The trapped ions are discharged from the end cap 31b by the potential applied to the end caps 31a and 31b at both ends in a pulse form, and are detected by the ion detector 8. In this ion trap type mass spectrometer, the degree of vacuum in the trap must be kept high. If the degree of vacuum in the trap is deteriorated, collision between the ions and the neutral gas occurs, and the trajectory of the ions is changed, so that the confinement of the ions is deteriorated. When charged droplets enter the trap, they impinge on the electrodes and vaporize, generating a neutral gas and deteriorating the degree of vacuum in the trap. Therefore, a configuration in which only ions are deflected and introduced into the ion trap section is effective. FIG. 15 shows a configuration in which the ion intake port 19 is provided in the ring electrode 32 in the ion trap type mass spectrometer. However, it goes without saying that the present invention is effective regardless of the position of the ion intake port. Also in the ion trap type mass spectrometer, it is desirable that the end cap or the ring electrode where the ion intake port 19 is opened be heated by a heater or the like in order to reduce contamination by the charged droplets.

FIG. 16 shows a configuration in which the present invention is applied to a mass spectrometer having a Fourier transform ion cyclotron resonance type as a mass spectrometer. In the Fourier transform ion cyclotron resonance type, the ions are cyclotron-moved under a high vacuum strong magnetic field, and the rotation frequency is set to an electrode 2 provided outside the vacuum vessel.
In this method, the mass of an ion is determined by performing a Fourier transform on the frequency spectrum detected by 5 ′.
Although this method has an extremely high resolution, the mass spectrometry unit requires a high degree of vacuum of 10 ⁻⁶ Pascal to 10 ⁻⁷ Pascal. Therefore, when ions are introduced from the atmosphere, a large number of ion introduction pores 15a, 15b,
15c and 15d, and the ion introduction pores 15a and 15d
5b, a portion between the ion-introducing pores 15b and 15c, and a portion between the ion-introducing pores 15c and 15d. Had to be used. FIG.
The method described in No. 6, which deflects only ions and separates them from liquid droplets and guides them to the next ion introduction pore, is effective because it can prevent deterioration of the vacuum degree of the mass spectrometric unit due to inflow of charged liquid droplets.

In addition to the above-described Fourier transform ion cyclotron type mass spectrometer, in order to efficiently transport charged particles such as ions and electrons to an ultrahigh vacuum section, as shown in FIG. A cylindrical electrostatic lens having an opening is divided into a plurality of different decompression units 36a, 36b, 36c, 36
The configuration of arranging over d is effective.

The definition of the central axis of the ion introduction pore in the present invention will be described just in case. It is preferable that the ion introduction pore 15 has a tapered shape as shown in FIG. 18, but such a shape is difficult to process, and therefore, usually, as shown in FIG. A hole of a predetermined shape, for example, a circular or square shape is formed. In the present invention, the central axis of the ion-introducing pore represents an axis passing through the center of the hole and extending in a direction normal to the plane of the tip.

[0026]

According to the present invention, the mass spectrometer is contaminated,
In addition, it is possible to prevent the charged droplets, which are sources of noise, from flowing into the mass spectrometer, and to efficiently analyze only ions. Therefore, the mass spectrometer can operate stably for a long time, and a high-sensitivity mass spectrometer with little noise can be realized. That is, the S / N ratio is increased about 10 times, and the sensitivity in the mass spectrometer is improved by one digit.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration using an electrostatic lens that deflects ions according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an example of an electrostatic lens for realizing the first embodiment of the present invention.

FIG. 3 is a sectional view showing an example of an electrostatic lens for realizing the first embodiment of the present invention.

FIG. 4 is a sectional view showing an example of an electrostatic lens for realizing the first embodiment of the present invention.

FIG. 5 is a sectional view showing an example of an electrostatic lens for realizing the first embodiment of the present invention.

FIG. 6 is a sectional view showing an example of an electrostatic lens for realizing a second embodiment of the present invention.

FIG. 7 is a sectional view showing an example of an electrostatic lens for realizing a second embodiment of the present invention.

FIG. 8 is a diagram illustrating an example of an electrostatic lens that accelerates or decelerates ions in an axial direction.

FIG. 9 is a diagram illustrating an example of an electrostatic lens that accelerates or decelerates ions in an axial direction.

FIG. 10 is a diagram showing a configuration in which the present invention is applied to a thermospray mass spectrometer.

FIG. 11 is a diagram showing a configuration in which the present invention is applied to a mass spectrometer in which a number of mass spectrometers are connected.

FIG. 12 is a diagram showing a configuration in which the present invention is used for a capillary electrophoresis / mass spectrometer.

FIG. 13 is a diagram showing a configuration in which the present invention is used for a mass spectrometer that generates plasma and generates ions in the plasma.

FIG. 14 is a diagram showing a configuration in which the present invention is applied to a mass spectrometer having an ion trap type mass spectrometer.

FIG. 15 is a diagram showing a configuration in which the present invention is used in a mass spectrometer having an ion trap type mass spectrometer.

FIG. 16 is a diagram showing a configuration in which the present invention is used in a mass spectrometer having a Fourier transform ion cyclotron resonance type mass spectrometer.

FIG. 17 is a diagram showing a configuration in which the present invention is applied to a mass spectrometer having a Fourier transform ion cyclotron resonance type mass spectrometer.

FIG. 18 is an enlarged view of an ion introduction pore.

FIG. 19 is an enlarged view of an ion introduction pore.

FIG. 20 is a diagram showing a configuration of a conventional liquid chromatograph / mass spectrometer.

FIG. 21 is a cross-sectional view showing the configuration of a conventional liquid chromatograph / mass spectrometer using the electrostatic spray method.

FIG. 22 is a diagram showing a configuration of an ion detector used in a conventional liquid chromatograph / mass spectrometer.

[Explanation of symbols]

1. Liquid chromatograph, 2. Piping, 3. Ion source,
4, 4a, 4b ... power supply, 5a, 5b ... signal line, 6 ...
Mass analyzer 7, 7, 7a, 7b: Exhaust system, 8: Ion detector, 9: Data processor, 10: Connector, 11: Spray capillary, 12: Counter electrode, 13: Spray gas outlet, 14
... Vaporization gas outlets, 15, 15a, 15b, 15c,
15d: ion introduction pore, 16: ion deflection electrode, 17
... Secondary electron emission electrode, 18 ... Electron detector, 19 ... Ion intake port, 20 ... Extraction electrode, 21, 21a, 21
b: electrostatic lens, 22: inner electrode, 23: opening, 24
... Outside electrode, 25, 25 '... Electrode, 26 ... Collision chamber, 27
... Capillary, 28 ... Electrophoresis power supply, 29 ... Oscillator, 30 ... Electric transmission path, 31 ... End cap, 32 ... Ring electrode, 33 ... Intermediate pressure part, 34 ... High vacuum part, 35 ... Metal cylinder, 36a, 36b , 36c, 36d...

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hirabayashi 1-280 Higashi Koikebo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Inventor Yoichi Kose 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Energy Laboratory

Claims (11)

[Claims] 1. An ionization section for ionizing a sample, a mass analysis section for analyzing ions of the sample generated by the ionization section, and an ionization section disposed between the ionization section and the mass analysis section. First and second openings for introducing the ions generated in the mass spectrometric unit into the mass analyzer, and disposed between the first opening and the second opening to deflect the ions. A mass spectrometer comprising: an electrostatic lens for focusing the light; and a central axis of the first opening different from a central axis of the second opening. 2. The mass spectrometer according to claim 1, wherein a central axis of said first opening and a central axis of said second opening are configured to be parallel. 3. The mass spectrometer according to claim 1, wherein a central axis of said first opening and a central axis of said second opening intersect. 4. The mass spectrometer according to claim 1, wherein said electrostatic lens comprises a cylindrical electrode. 5. A first and a second opening disposed between an ionization section for ionizing a sample under atmospheric pressure and a vacuum section, for introducing ions generated in the ionization section into the vacuum section. And, disposed between the first opening and the second opening,
A mass spectrometer having a region for generating an electrostatic field for deflection convergence, wherein the central axis of the first opening and the central axis of the second opening are different. 6. A first and a second opening disposed between an ionization section for ionizing a sample under atmospheric pressure and a vacuum section, for introducing ions generated in the ionization section into the vacuum section. And, provided between the first opening and the second opening,
A mass spectrometer comprising: a cylindrical electrode arranged so that its central axis is different from the central axis of the second opening. 7. An ionization section for ionizing a sample to be analyzed, a cylindrical electrode disposed next to the ionization section, and an opening disposed next to the cylindrical electrode to extract the ions. A mass spectrometer characterized in that the ions from the ionization section are incident on the cylindrical electrode from a position distant from the central axis of the cylindrical electrode. 8. An electrostatic lens comprising: an inner electrode having an opening; an outer electrode disposed outside the inner electrode; and an opening provided in the outer electrode. 9. An opening area of said opening of said outer electrode is:
9. The electrostatic lens according to claim 8, wherein the electrostatic lenses are configured differently. 10. An internal electrode having an opening, and an external electrode disposed outside the internal electrode, wherein different voltages are applied to both ends of the external electrode. Electrostatic lens. 11. An inner electrode having an opening and an outer electrode disposed outside the inner electrode, wherein the inner electrode and the outer electrode are disposed so as to penetrate a pressure partition. An electrostatic lens characterized by the following.