JPH08148117A - Ionization analyzer - Google Patents

Abstract

PURPOSE: To provide an ionization analyzer improving the generating efficiency of ions used for mass spectrometry. CONSTITUTION: A needle 22 reciprocative in the (z) direction is stored in an ionization chamber 15, and an electrolyte solution L containing a sample is fed via a fine tube 18. A hole 20 penetrated into the ionization chamber 15 is bored on the fine tube 18, and the tip of the needle 22 is inserted into the hole 20 while a prescribed voltage E1 is applied. Ions are stuck to the tip via electrophoresis, the needle 22 is lifted, then the polarity of the voltage E1 is reversed, and the ions stuck to the tip of the needle 22 are discharged into the ionization chamber 15. The evaporation of the liquid of the electrolyte solution L is suppressed and ions can be concentrated into soft ions.

Description

Detailed Description of the Invention

[0001]

The present invention relates to ionization (so-called soft ionization) of biopolymers, proteins, sugar chains, DNA, drugs and other hardly volatile polymers without decomposition, and mass spectrometry of the polymers. And an ionization analyzer for performing.

[0002]

2. Description of the Related Art Conventionally, in an ionization analyzer that performs such mass spectrometry of a sample by soft ionization,
Techniques such as laser desorption and electrospray method are known.

The laser desorption method is based on the principle that soft ionization is achieved when a substance (matrix) that absorbs laser is irradiated. That is, this method solves the problem that soft ionization cannot be realized because the polymer is decomposed when only the polymer is irradiated with a laser.

On the other hand, the electrospray ionization analyzer has a structure as shown in FIG.
About 10 times the electrolyte solution L containing the ion-dissociated sample
It is supplied to a capillary 1 having an inner diameter of 0 μm or less, and an electric field generated by a high voltage applied to the capillary 1 causes the tip 2 to be needle-shaped and atomized into ion droplets 3 having a diameter of about 1 μm. Release to middle R. Further, the R in the atmosphere is subjected to differential evacuation in which N ₂ gas is supplied from a predetermined supply port while being sucked by a vacuum pump (not shown). In this way, the atomized ion droplets 3
As shown in FIG. 21, the ionic liquid droplets 3 whose volume is gradually reduced or split due to solvent evaporation and whose surface area has been reduced.
Internal ions (sample ions and solvent ions) on the surface of
Move and the droplet radius reaches a predetermined critical point (about 10 nm), Coulomb repulsion between the ions causes the ions to be ejected (so-called ion evaporation). Then, a mass spectrum is obtained by introducing the ions into the mass spectrometer 5 through the ion introducing unit 4 of the mass spectrometer and detecting them by the ion detector 6.

[0005]

However, in the above-described laser desorption method, the amount of the matrix with respect to the sample is as large as 10 ⁶ times, and all of this is evaporated, so that the ions of the sample are mass spectrometers. The efficiency introduced to
There is a problem of extremely low as 10 ^-6 to 10 ^-10.

In the ionization analyzer by the electrospray method, when the concentration of the sample with respect to the solvent is increased, the volume of the ion droplet does not shrink until it reaches the critical point, and ion evaporation does not occur. . Also,
When a non-organic solvent such as water is applied, there is a problem that atomized ion droplets are not emitted from the tip of the capillary. For the purpose of eliminating such a situation where atomization is not sufficiently performed, a method of increasing the electric field strength in the atmosphere and supplying energy for atomization may be taken, but a discharge phenomenon occurs. There is a problem that it is easy.
In addition, the electrospray method also evaporates all the solvent including the sample and discharges the solvent by differential evacuation, so that the efficiency of introducing ions into the mass spectrometer is 10 ⁻⁶ to 10 ⁻¹⁰ . There is the problem of being extremely low.

In the FD (field desorption) method, a sample is placed on a needle and the dried sample is inserted into a vacuum atmosphere for ion evaporation under a high electric field of several kV. It is not practical because it takes about one day. Further, in order to omit the complicated work of the FD method, it is proposed to eject the liquid chromatograph effluent toward a nozzle and to apply a high voltage to a needle on which the sample is placed to ionize the sample (Japanese Patent Laid-Open No. Hei 3). -28524
However, it is difficult to say that the efficiency of ionization of the sample is high, and there are problems such as causing an abnormal discharge and causing a background because the medium itself is ionized. is there.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an ionization analyzer which is excellent in the efficiency of introducing a sample into a mass spectrometer and, in turn, in improving the sensitivity. And

[0009]

In order to achieve such an object, the present invention provides an ionization analyzer for releasing ions of a sample contained in an electrolyte solution into the air or vacuum in an ionization chamber. A needle provided in the ionization chamber, an attachment means for attaching ions in the electrolyte solution to the tip of the needle, and a voltage having a predetermined polarity corresponding to the charge polarity of the ions to the needle, And an ion emitting means for emitting the ions.

Further, the adhering means is provided with a moving means for supplying the electrolyte solution into the ionization chamber and moving the needle so that the tip of the needle temporarily comes into contact with the electrolyte solution.

Further, the needle is fixed in the ionization chamber, and the adhering means is a thin tube or a supply tube for supplying the electrolyte solution to the vicinity of the needle and the electrolyte solution by vibrating the thin tube or the supply tube. And a vibrating means for adhering the electrolyte solution to the tip of the needle by moving the surface of the needle.

Further, the adhering means has a thin tube or a supply tube for supplying the electrolyte solution to the ionization chamber, and the needle is so arranged that the tip of the needle projects into the ionization chamber when moved in a predetermined direction. The structure is such that it can be moved back and forth in a thin tube or a supply tube.

Further, the moving means is constructed so that the tip of the moving means is brought into contact with the electrolyte solution temporarily by vibrating the needle.

An ultrasonic vibrator is applied to the vibrating means.

The needle has a structure in which a surface of the needle is coated with a dielectric film or a substance that repels an electrolyte solution.

Further, the ion emitting means has a structure in which a voltage is applied to the needle or gas is supplied to the needle.

[0017]

When the needle comes into contact with an electrolyte solution containing the sample in which ions are dissociated, the ions of the sample are electrophoresed and the ions of the sample are electrophoresed due to the electric field generated between them by the voltage applied to the needle. Adhere to. That is, the ions are concentrated at the tip of the needle. Then, when the needle is pulled away from the electrolyte solution, evaporation of the ions of the sample attached to the tip of the needle occurs, further ionization is accelerated by the introduced gas or the like, and further when a voltage of a predetermined polarity is applied to the needle. , Ions of the attached sample are released into the ionization chamber. Therefore, soft ionization is realized quickly and with high efficiency.

[0018]

【Example】

(First Embodiment) First of the ionization analyzer according to the present invention
Embodiments will be described with reference to the drawings. In this embodiment, T
The present invention relates to an ionization analyzer applied to an OF mass spectrometer. First, referring to FIG. 1, a schematic structure of the TOF mass spectrometer will be described. A drift region 11 is provided in a container 10 which is airtight and whose inside is sucked by a vacuum pump (not shown). A microchannel plate 12 having an electron multiplying function is arranged behind the drift region 11, and ions acceleratedly incident from the front of the drift region 11 pass through the drift region 11 and reach the microchannel plate 12. It is like this. The detection signal S output from the anode of the microchannel plate 12 is amplified by the preamplifier 13 and recorded by the recording unit 14 such as a transient recorder capable of high-speed recording.

On the other hand, the ionization analyzer of this embodiment has a container-shaped ionization chamber 15 which is integrally connected to the container 10 in front of the drift region 11, and the ionization chamber 15 also has a structure having airtightness. Has become. N ₂ gas is supplied into the ionization chamber 15 from a supply port 16 provided at its lower end, and exhausted by a vacuum pump (not shown) from a port 17 at its upper end. Further, not only N ₂ gas but also non-volatile gas may be supplied. The reason for introducing such a gas is to suppress the generation of unnecessary evaporative substances in the process of collecting and releasing the ions of the sample to be measured contained in the electrolyte solution described later. Yes, in some cases, without introducing such a gas,
The inside of the ionization chamber 15 may be in a vacuum state.

In the following description, the electrolyte solution means a so-called sample solution prepared by mixing a substance as a sample to be measured (for example, living cells or other substances) in a solvent. And That is, in this example, an electrolyte solution in which the sample to be measured is dissociated into cations and anions according to the pH concentration of the solvent is introduced, and the ions of the sample to be measured are collected from the electrolyte solution. Release to mass spectrometer.

At the lower end of the ionization chamber 15, an electrolyte solution L
A supply pipe 18 is provided for supplying the electrolyte solution L to the supply pipe 18 by a shrinkage pump 19 or the like. A minute hole 20 communicating with the inside of the ionization chamber 15 is formed on one side of the supply pipe 18.

Further, in the ionization chamber 15, a cylindrical grid 21 facing the holes 20 at a predetermined interval.
Is fixed, and about 1 μm to several 10s with respect to the hole 20.
A needle 22 movable in the vertical direction (z direction in the drawing) within a range of about μm is inserted in the hollow of the grid 21.

One end of the needle 22 is connected to a piezoelectric element or an ultrasonic vibrating element built in the moving device 23, and the vertical movement of the needle 22 is controlled by operating these elements. A variable voltage source 24 and an ammeter 25 are connected in series between the needle 22 and the supply pipe 18. The variable voltage source 24 can variably control the control voltage E1 in a range from minus to plus. Therefore, with respect to the needle 22, the supply pipe 18
The control voltage E1 for increasing the potential of the supply tube 18 is output to the needle 22 and vice versa.
Can be output, or the control voltage E1 (that is, E1 = 0 volt) that makes the needle 22 and the supply pipe 18 have the same potential can be output, and the respective voltage levels can be set appropriately.

Above the grid 21, the drift region 1
Corresponding to the grid 26 provided in front of 1, grids 27 and 28 are arranged in parallel. Grid 2
6 is the earth potential (0 volt) together with the drift region 11.
The grids 27, 28 are set to a voltage source 30 controlled by a control unit 29 including a computer system.
Pulse control voltages V1 and V2 (where 0 <V2 <V
1) is applied at a predetermined timing.
Then, as will be described later, the ions of the sample are transferred to the grid 27.
When the pulse control voltages V1 and V2 are applied to the grids 27 and 28 while accumulating in the space between and, the cations are accelerated to the grid 26 side and are sent to the drift region 11, and mass spectrometry etc. Will be offered to.

Further, the structure of the grids 21, 27 and 28 will be described in detail with reference to FIG. The grid 21 is a cylindrical tube made of an insulating material having an inner diameter into which the needle 22 can be inserted, for example, an inner diameter of about 10 μm to about 100 μm. It is formed by processing. Then, by applying a predetermined voltage E2 between the upper end 21a on the grid 27, 28 side and the lower end 21b corresponding thereto, a predetermined electric field gradient is generated inside the grid 21. ing. When treating the cations of the sample, as shown in FIG. 2, a voltage E2 that raises the potential of the lower end 21b with respect to the upper end 21a is applied, and conversely,
When treating the anions of the sample, a voltage E2 that lowers the potential of the lower end 21b is applied with respect to the upper end 21a. On the other hand, the grids 27 and 28 are formed of metal nets parallel to each other.

The grid 21 is, as shown in FIG.
A plurality of metal rings 21c to 21e arranged in the z direction are arranged in parallel at predetermined intervals, and the metal rings 21c to 21e
An electric field gradient may be generated by applying a predetermined voltage E20, E21 between 21e. In the grid 21 shown in FIG. 3, when treating the cations of the sample, as shown in FIG. 3, voltages E20 and E21 that bring the metal ring 21c to the lowest potential are applied, and conversely,
When processing the anions of the sample, the metal ring 21c
The voltages E20 and E21 that make the highest potential are applied.

Next, the operation of the embodiment having the above construction will be described. In addition, the case where mass spectrometry etc. of a cation are carried out is demonstrated as a representative. In this case, as shown in FIG. 1, the lower end 21b of the grid 21 has a high potential, and the upper end 21b of the grid 21 has a high potential.
A voltage E2 is applied which sets a to a low potential.

Then, as shown in FIG. 4, with the electrolyte solution L flowing into the supply pipe 18, the needle 22 is lowered toward the hole 20 and the tip of the needle 22 is brought into contact with the electrolyte solution L.
At this time, the polarity of the control voltage E1 is set so that the supply tube 18 has a higher potential than the needle 22. As a result, the cations of the sample move to the tip of the needle 22 by electrophoresis, so that the cations are concentrated and attached.

Next, as shown in FIG. 5, the needle 22 is pulled out from the hole 20 and pulled up to a predetermined height while the control voltage E1 having the polarity is applied. Therefore, high-concentration cations remain attached to the tip of the needle 22. However, the cations of this sample bond with the electrons supplied together with the control voltage E1 and attach in an electrically neutral state.

Next, as shown in FIG. 6, by inverting the polarity of the control voltage E1, the needle 22 is set to a positive potential with respect to the supply pipe 18. As a result, the cations attached to the needle 22 are repelled and released by the electric field, released by ion evaporation, or released by the Coulomb repulsive force of itself. Then, the cations thus released are moved to the gaps between the grids 27 and 28 according to the electric field gradient by the grid 21.

Here, as shown in FIGS. 4 and 5, in order to attach cations to the tip of the needle 22 against the mutual Coulomb force, the diameter of the tip of the needle 22 is about 100 pieces. It is desirable to set the control voltage E1 of the reverse polarity shown in FIG. 6 to about several volts in order to release these cations by about 10 nm. Naturally, the needle 22
If the tip of is sharpened, a high electric field is locally generated, and cations can be attached to the tip in high concentration.
Considering the application of the apparatus of this embodiment to a general mass spectrometer, the diameter of the tip of the needle 22 is about 5 nm to 0.5.
It is preferable to design to μm.

Further, in this embodiment, the cations are injected into the needle 22.
In order to release the cations with high efficiency (see FIG. 6), the control voltage E1 of the opposite polarity is supplied, but without applying a voltage to the needle 22 (E1 = 0 volt), the cations are ionized by themselves. It may be released into the chamber 15.

Next, from the voltage source 30 to the grids 27, 28.
By applying the above-mentioned predetermined pulse control voltages V1 and V2, the cations existing between the grids 27 and 28 are accelerated to the drift region 11 to fly. Then, the cations that have reached the microchannel plate 12 are photoelectrically detected, and the detection signal S is recorded by the recording unit 12 to obtain the mass spectrum of the sample to be measured. That is, T
The OF mass spectrometer can determine the mass spectrum of the sample to be measured by detecting its flight time, because the flight speed of the ion beam in the sample to be measured varies in the drift region 11. it can.

In the above description of operation, the case where the cations of the sample to be measured are collected and released is described. However, when the anions are processed, the control voltages E1 and E2 and the pulse control voltages V1 and The polarity of V2 will be set opposite to the above description. That is, in the process shown in FIGS. 4 and 5, the control voltage E1 for increasing the potential of the needle 22 is applied to the supply pipe 18, and in the ion ejection process shown in FIG. A control voltage E1 for lowering the potential of is applied or set to E1 = 0 volt, and the pulse control voltages V1 and V2 are set to negative voltages (V1 <V2 <0).

In FIGS. 4 and 5, the control voltage E1 is applied to attach the cations or anions to the tip of the needle 22, but the control voltage E1 is not applied (that is, E1).
After the electrolytic solution is attached to (= 0), positive or negative ions may be emitted by applying a control voltage E1 having a predetermined polarity as shown in FIG. That is, in the ion ejection process shown in FIG. 6, positive ions can be emitted by applying a positive control voltage E1 to the needle 22, and negative ions can be emitted by applying a negative control voltage E1 to the needle 22. Can be released.

Thus, according to this embodiment, the needle 22
The ion of the sample to be measured is attached by contacting the tip of the sample with the electrolyte solution L containing the sample to be measured, and then the needle 22 is separated from the electrolyte solution L to apply a voltage of a predetermined polarity to the needle 22. By doing so, the ion of the sample is released, so the operation is extremely simple,
In addition, the problem that the unnecessary electrolyte solution is ionized and the measurement accuracy is deteriorated as in the conventional case is solved. Further, the ionization of the sample in the conventional FD method is
Provide an electrically neutral and dry sample substance at the tip of the needle,
A high voltage is applied to this needle to emit an electron to generate a desired ion. However, in this embodiment, the ions of the sample that have undergone ion dissociation in the electrolyte solution L are sampled by the needle 22 and a predetermined voltage is applied to the needle 22 to release the collected ions. Therefore, there is a significant difference in the so-called ionization mechanism. Further, the control voltage E1 required to attach the ions to the needle 22 or to release them thereafter may be several volts, which is an excellent effect that the voltage is extremely low as compared with the FD method.

The needle 22 of this embodiment is shown in FIG.
It is a metal needle having a relatively simple truncated cone-shaped tip portion as shown in, but is not limited to this. For example, as shown in FIG. 7B, the tip of the needle may be covered with a dielectric film C, or as shown in FIG. 7C, the entire needle may be covered with a dielectric film C. As shown in (d) of the same figure, a spherical portion B is formed at the tip of the needle, or as shown in (e) of the same, the needle is coated with a dielectric film C, or Teflon or an organic substance is used. Such a material C, that is, a material that repels the electrolyte solution, is provided with a sphere B at its tip, and a sharp small projection is provided at the lower end of the sphere B, as shown in FIG. Applying a needle consisting of a thin hollow tube, or the same figure (g)
As shown in FIG. 3, the surface of the spherical portion B formed at the tip of the needle is covered with the dielectric film C, and the other portion is covered with the material (Teflon etc.) C that repels the electrolyte solution. Good.

The point is that the cations or anions of the sample in the electrolyte solution L can be easily attached to the tip of the needle and can be easily released, and combinations of these modes and other shapes can be used. May be.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG. In addition, in each component in FIG. 8, the same or corresponding portions as in FIG. 1 are denoted by the same reference numerals. Described below are the differences from the embodiment shown in FIG.
At the lower end of the ionization chamber 15 of the ionization analyzer, a capillary tube 31 for introducing the electrolyte solution L is provided up to the inside thereof, and further, in the capillary tube 31, a thin needle 32 that can move back and forth in the z direction. Has been inserted. That is,
When the needle 32 advances to the inside of the ionization chamber 15, the needle 32
When the needle 32 protrudes into the ionization chamber 15 and the needle 32 retracts into the capillary tube 31, the tip is housed in the capillary tube 31.

Further, a voltage source 2 for applying a control voltage E1 having a predetermined polarity between the capillary tube 31 and the needle 32.
4 is connected, and a voltage E3 having a predetermined polarity is also applied between the capillary tube 31 and the grid 21.

Next, the operation of this embodiment will be described with reference to FIGS. 8 to 10 showing the cross section of the main part of the ionization analyzer. The case of treating cations will be described. In this case, as shown in FIG. 8, the lower end of the grid 21 (the needle 32
Is applied), a predetermined electric field gradient is generated by applying a voltage E2 that sets a high electric potential on the
The voltage E3 is set so that the capillary tube 31 has a high potential with respect to the grid 21.

Next, as shown in FIG. 9, the electrolyte solution L is supplied to the capillary tube 31, and the needle 32 is moved to the inside of the ionization chamber 15. At this time, at the same time, the capillary tube 31
A control voltage E1 is applied to bring the needle 32 to a lower potential. As a result, due to the electric field generated between the capillary tube 31 and the needle 32, the cations in the electrolyte solution L are concentrated and attached to the tip of the needle 32 by electrophoresis. Then, the needle 32 is advanced to a distance beyond the surface tension of the electrolyte solution L.

Next, as shown in FIG. 10, the control voltage E1
The polarity of the needle 32 is reversed and the potential of the needle 32 is increased with respect to the capillary tube 31. As a result, the cations attached to the needle 32 are released into the ionization chamber 15, and the cations are generated in the grids 27, 28 by the electric field gradient of the grid 21.
To move between. Then, the grid 2 is generated by the voltage source 23.
By applying positive pulse control voltages V1 and V2 to 1 and 22, positive ions are emitted to the drift region 11 and caused to fly, and the recording unit 14 determines the mass spectrum based on the signal S detected by the microchannel plate 12. Record.

As described above, in the second embodiment, the electrolyte solution containing the ion-dissociated sample is attached to the tip portion of the needle 32 to enter the ionization chamber 15, and at the same time, the needle By applying a predetermined control voltage E1 to 32, the cations are concentrated and attached, and by applying a control voltage E1 of the opposite polarity to the needle 32, the cations are released, so that the operation is extremely simple. is there. The control voltage E1 for this control may be about several volts. Further, the problem of unnecessarily ionizing the electrolyte solution and hindering the measurement as in the conventional case is solved. Also,
As shown in FIGS. 7B to 7G, the tip or the whole of the needle 32 is covered with the dielectric coating 32 a, and the control voltage E 1 as described above is applied to the metal portion inside the needle 32, whereby the needle 32 is applied. An electric field can be efficiently applied to the tip of the.
If the coating 32a is made of a material such as Teflon, the needle 32
Since it is possible to easily separate the electrolyte solution adhering to the tip portion of the and the electrolyte solution L in the capillary tube 31,
The process for releasing ions can be rapidly moved to, and the overall processing time for ionization can be shortened.

In the above description of operation, the case of processing positive ions has been described. However, when processing negative ions, the polarities of the control voltages E1 to E3 and the pulse control voltages V1 and V2 are set to the positive values. This is the reverse of the case of processing ions.

As a modification of the second embodiment, a needle and a structure for supplying an electrolyte solution may be as shown in FIG. That is, FIG. 11 corresponds to FIG. 9 and FIG.
11 is a partial cross-sectional view corresponding to 0, and instead of the capillary tube 31 in FIG. 10, a supply tube 18 similar to that shown in FIG.
Is provided at the lower end of the ionization chamber 15, and holes 33 and 34 penetrating to the ionization chamber 15 are formed at one end of the supply pipe 18. The needle 32 is inserted into the holes 33 and 34, and the gap between the hole 34 and the needle 32 is sealed by a flexible seal member 35. Then, FIGS.
In the same manner as shown in Fig. 3, the needle 32 is applied while applying the control voltage E1.
By invading the inside of the ionization chamber 15, desired ions can be attached to the tip of the needle 33, and the attached ions can be released by setting the control voltage E1 to a predetermined polarity. .

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. In addition, in each component in FIG. 12, the same or corresponding portions as those in FIG. 1 are denoted by the same reference numerals. The difference from the embodiment shown in FIG. 1 will be described. At the lower end of the ionization chamber 15, up to the inside thereof,
A capillary tube 40 for introducing the electrolyte solution L is provided, and a needle 22 penetrating the hollow portion of the grid 21 and facing the tip portion of the capillary tube 40 is fixed inside the ionization chamber 15. ing. That is, the needle 22 shown in FIG. 1 is adapted to move back and forth along the z direction, whereas the needle 22 shown in FIG. 12 is fixed. However, the tip of the needle 22 and the tip of the capillary tube 40 are separated by a gap of about several μm.

An ultrasonic transducer 41 is attached to the tip of the capillary 40. Then, when the ultrasonic oscillator 41 vibrates due to an alternating current from an alternating current power source (not shown), the electrolyte solution L is vibrated via the capillary 27. Further, a voltage source 24 for applying a control voltage E1 having a predetermined polarity is connected between the capillary tube 40 and the needle 22.

Next, the operation of this embodiment will be described with reference to FIGS. 13 and 14 showing the cross section of the main part of this ionization analyzer. The case of collecting and releasing cations from the electrolyte solution L will be described. First, as shown in FIG. 12, the lower end of the grid 21 (the side of the capillary tube 40) is set to a high potential,
A voltage E2 that sets the upper end to a low potential is applied to generate a predetermined electric field gradient in the grid 21.

Next, as shown in FIG. 13, the electrolyte solution L is supplied to the capillary tube 40 to vibrate the ultrasonic transducer 41, and at the same time, the capillary tube 40 is set to a high potential and the needle 22 is set to a low potential. The voltage E1 is applied. As a result, the vibrated liquid surface of the electrolyte solution L rises and adheres to the tip of the needle 22, and the cations in the electrolyte solution L are affected by the electric field generated by the control voltage E1 and are subjected to so-called electrophoresis. Attach to the tip of 22. Therefore, the cations are concentrated and attached to the tip of the needle 22 without moving the needle 22.

Next, after stopping the vibration of the ultrasonic transducer 41, as shown in FIG. 14, the polarity of the control voltage E1 is reversed to increase the potential of the needle 22 with respect to the capillary tube 27. As a result, cations are released from the tip of the needle 22, and the released cations move between the grids 27 and 28 due to the electric field gradient of the grid 21, and
The pulse control voltage V is applied to the grids 27 and 28 from the voltage source 30.
When 1 and V2 are applied, they enter the drift region 9 and the recording unit 14 records the mass spectrum of the sample to be measured based on the signal detected by the microchannel plate 12.

As described above, in the third embodiment, the electrolyte solution L is attached to the tip of the needle 22 by vibrating by the ultrasonic transducer 41, and therefore, as in the embodiment shown in FIG. It is not necessary to adjust the moving position of the needle, so that the device can be simplified and the mechanical accuracy can be improved. Also,
The problem that the unnecessary electrolyte solution is ionized and interferes with the measurement as in the past is solved.

In the above description of the operation, the case of processing positive ions has been described, but in the case of processing negative ions, the polarities of the control voltages E1 and E2 and the pulse control voltages V1 and V2 are described above. It will be set in reverse.

As a modification of the third embodiment, a structure for attaching the electrolyte solution to the needle is shown in FIG.
You may make it show in. That is, FIG. 15 is a partial cross-sectional view corresponding to FIGS. 13 and 14, and instead of the capillary tube 40 in FIG. 12, a supply tube 18 similar to that shown in FIG. 1 is provided at the lower end of the ionization chamber 15. A hole 42 is provided at one end of the supply pipe 18 and is connected to the ionization chamber 15. Further, an ultrasonic transducer 41 is fixed to the side wall of the supply pipe 18 facing the hole 42.

Then, similarly to the case shown in FIGS. 13 and 14, when the ultrasonic oscillator 41 is vibrated while applying the control voltage E1, a part of the electrolyte solution L is transferred from the hole 42 to the tip of the needle 22. Ejection, positive ions 2 depending on the polarity of voltage E1
It will be concentrated and attached to the tip of 2. Then, when the polarity of the voltage E1 is reversed, cations are released from the tip of the needle 22 into the ionization chamber 15 and used for mass spectrometry or the like.

(Fourth Embodiment) Next, a fourth embodiment will be described with reference to FIG. The same or corresponding constituent elements as those in FIG. 1 of the first embodiment are designated by the same reference numerals. In FIG. 16, at the lower end of the ionization chamber 15, the ionization chamber 15
A capillary tube 50 for supplying N ₂ gas is connected to the capillary tube 50, and a capillary tube 51 for supplying the electrolyte solution L from a direction substantially orthogonal to the capillary tube 50 is provided. Then, a hole 52 having a diameter of about 1 μm to 10 μm is formed on one side of the capillary tubes 50 and 51 by laser processing or the like, so that the capillary tube 51 is provided inside the ionization chamber 15 through the hole 52. Is in communication with. Further, in the capillary tube 29, on the side wall facing the hole 52,
Hole 5 of about 10 to 50 μm due to laser processing, etc.
3 is drilled. The needle 22 is inserted into the hole 53, and the gap between the hole 53 and the needle 22 is sealed by the flexible sealing material 54. The needle 22 is shown in FIGS.
The shape of the needle 22 is connected to a piezo element, an ultrasonic vibration element, or the like housed in the drive mechanism 23, and driven by these elements, so that the tip of the needle 22 is inside the hole 52. It is designed to be inserted into or pulled out of. Further, a voltage source 2 for applying a control voltage E1 having a predetermined polarity between the needle 22 and the capillary tube 51.
4 are connected.

Further, the outer peripheral surface of the portion of the capillary tube 50 protruding into the ionization chamber 15 is covered with a coating 55 made of a high-resistance conductive material, and the upper end of the coating 55 (on the grid 27, 28 side). ) And the lower end, a voltage E2 having a predetermined polarity as shown is applied. The structure after the grids 27, 28 is the same as in FIG.

Next, the operation of this embodiment will be described. still,
The case of treating cations will be described. First, the electrolyte solution L is supplied by the capillary tube 51, and the tip of the needle 22 is inserted into the hole 52. At this time, the polarity of the control voltage E1 is set so as to increase the potential of the capillary tube 51 with respect to the needle 22. Therefore, the cations are concentrated and attached to the tip of the needle 22.

Next, by retracting the needle 22 from the hole 52, the needle 22 is separated from the electrolyte solution L and the polarity of the control voltage E1 is reversed. That is, the polarity of the control voltage E1 is inverted so as to lower the potential of the capillary tube 51 with respect to the needle 22. As a result, the cations attached to the tip of the needle 22 are released and moved between the grids 27 and 28 according to the electric field gradient generated by the coating film 55, and the grid 2 is further moved.
It is introduced into the drift region 11 by applying pulse control voltages V1 and V2 to 7 and 28.

When the cations attached to the tip of the needle 22 are released, the gas supplied from the capillary tube 50 contains a solvent and a solvent in order to suppress evaporation of the electrolyte solution attached to the tip. It is desirable to include water vapor of the same quality. Further, for example, when the capillary tube 29 having an inner diameter of 30 μm and a length of 1 cm is applied, the leak amount Q is 4
× 10 ^-3 (Torr l / sec), and the ionization chamber 13
The exhaust speed V by the exhaust vacuum pump connected to
When it is set to 00 (l / sec) to 1000 (l / sec), the internal pressure of the ionization chamber 15 is Q / V = 4 × 10 ⁻⁶ to 4 × 10 ⁻⁵ (Tor
r), the ionization chamber 15 can be brought to a sufficient vacuum state.

Further, the gas introduction end (1
It is desirable to suppress the evaporation of the electrolyte solution L by making the distance to the hole 52 shorter than (atmospheric pressure) and bringing the pressure in the hole 52 close to 1 atm.

(Fifth Embodiment) Next, a fifth embodiment will be described with reference to FIG. The same or corresponding constituent elements as those in FIG. 1 of the first embodiment are designated by the same reference numerals. In FIG. 17, the difference from the first embodiment will be described. A capillary tube 60 accommodating the needle 22 is provided in the ionization chamber 15, and the lower end of the capillary tube 60 is formed in the supply tube 18. It is connected to the hole 20, the other end communicates with the supply port 16, and the upper end is opened to face the grids 27 and 28. Further, the outer surface of the capillary tube 60 is covered with a high resistance conductive coating 61. Then, a voltage E2 having a predetermined polarity is applied to the upper and lower ends of the conductive coating film 61 to generate an electric field gradient in the hollow portion.

In this embodiment having the above-mentioned structure, the voltage E1 and the voltage E2 are set to the predetermined polarities and the needle 2 is used as in the first embodiment.
Ions of the electrolyte solution L can be attached to 2 and either cations or anions can be released and subjected to mass spectrometry.

(Sixth Embodiment) Next, a sixth embodiment will be described with reference to FIG. In addition, FIG. 12 of the third embodiment.
The same or corresponding components as those of FIG. 17 of the fifth embodiment are designated by the same reference numerals. Referring to FIG. 18, the difference from the third and fifth embodiments will be described. A capillary tube 40 for supplying the electrolyte solution L is connected to the lower end of the ionization chamber 15, and the tip of the capillary tube 40 is connected. The ultrasonic transducer 41 is fixed to the portion. Further, a capillary tube 60 accommodating the needle 22 is provided in the ionization chamber 15, the lower end of the capillary tube 60 faces the upper end of the capillary tube 40, the other end communicates with the supply port 16, and the upper end further has a grid 27. , 28 are open to face each other. Further, the outer surface of the capillary tube 60 is covered with a high resistance conductive coating 61. Then, a voltage E2 having a predetermined polarity is applied to the upper and lower ends of the conductive coating film 61 to generate an electric field gradient in the hollow portion.

Like the third and fifth embodiments, the present embodiment having such a configuration sets the voltage E1 and the voltage E2 to predetermined polarities and vibrates the ultrasonic transducer 41 to cause the needle 22 to vibrate.
It is possible to attach the ions of the electrolyte solution L with the particles fixed, and further to release either the cations or the anions for mass spectrometry.

(Seventh Embodiment) Next, a seventh embodiment will be described with reference to FIG. Incidentally, FIG. 8 of the second embodiment,
The same or corresponding components as in FIG. 17 of the fifth embodiment are designated by the same reference numerals. Referring to FIG. 19, the difference from the second and fifth embodiments will be described. A capillary tube 31 for supplying the electrolyte solution L is connected to the lower end of the ionization chamber 15 and the inside of the capillary tube 31 is connected. Has a needle 32 that can move back and forth. Further, a capillary tube 60 extending from the lower end to the grids 27, 28 side is provided in the ionization chamber 15, and one end of the capillary tube 60 communicates with the supply port 16. The outer surface of the capillary tube 60 is coated with a high resistance conductive coating 61. Then, a voltage E2 having a predetermined polarity is applied to the upper and lower ends of the conductive coating film 61 to generate an electric field gradient in the hollow portion.

Like the second and fifth embodiments, the present embodiment having such a configuration sets the voltage E1 and the voltage E2 to predetermined polarities and vibrates the ultrasonic transducer 41 to cause the needle 32 to vibrate.
It is possible to attach the ions of the electrolyte solution L with the particles fixed, and further to release either the cations or the anions for mass spectrometry.

[0068]

According to the present invention as described above,
An electrolyte solution containing a sample is attached to the surface of the needle, and a predetermined electric field is applied to the needle to ionize the attached sample, which promotes ionization with high efficiency without evaporating the electrolyte solution. it can. Therefore, it is possible to realize mass spectrometry or the like with higher accuracy than the conventional technique in which the vapor of the electrolyte solution has hindered mass spectrometry or the like.

Further, by applying a predetermined voltage to the thin needle, the electrolyte solution containing the sample is attached to the tip by electrophoresis, so that the sample is placed on the probe and dried as in the conventional technique. It is possible to eliminate complicated work such as ionization. Further, according to the present invention, mass spectrometry and the like can be easily continuously processed.

Further, according to the present invention, the sample is ionized by applying a predetermined voltage to the needle to which the electrolyte solution containing the sample is attached. This applied voltage is 2 times as compared with the known field ionization method. The purpose can be sufficiently achieved with a voltage that is an order of magnitude lower. That is, in the field ionization method, since a high voltage is applied to the same needle, even the solvent is ionized due to the tunnel current, and it is mixed with the ions of the sample to be measured, which limits the improvement of measurement accuracy. However, in the present invention, in combination with the above-described improvement in sensitivity, generation of unnecessary ions can be suppressed and the measurement accuracy in mass spectrometry or the like can be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a first embodiment of an ionization analyzer according to the present invention.

FIG. 2 is an enlarged perspective view showing the configuration of the grid in FIG.

FIG. 3 is an enlarged perspective view showing another configuration of the grid in FIG.

FIG. 4 is an explanatory diagram illustrating an operation of the first embodiment.

FIG. 5 is an explanatory diagram further explaining the operation of the first embodiment.

FIG. 6 is an explanatory diagram further explaining the operation of the first embodiment.

FIG. 7 is a partial vertical cross-sectional view showing the shape of a needle provided in the embodiment.

FIG. 8 is a vertical cross-sectional view showing the configuration of the second embodiment of the ionization analyzer of the present invention.

FIG. 9 is an explanatory diagram illustrating an operation of the second embodiment.

FIG. 10 is an explanatory diagram further explaining the operation of the second embodiment.

FIG. 11 is a longitudinal sectional view of an essential part showing the structure of a modified example of the second embodiment.

FIG. 12 is a vertical cross-sectional view showing the configuration of a third embodiment of the ionization analyzer of the present invention.

FIG. 13 is an explanatory diagram illustrating an operation of the third embodiment.

FIG. 14 is an explanatory diagram further explaining the operation of the third embodiment.

FIG. 15 is a longitudinal sectional view of an essential part showing the structure of a modification of the third embodiment.

FIG. 16 is a longitudinal sectional view of an essential part showing the configuration of a fourth embodiment of the ionization analyzer of the present invention.

FIG. 17 is a longitudinal sectional view of an essential part showing the configuration of a fifth embodiment of the ionization analyzer of the present invention.

FIG. 18 is a longitudinal sectional view of an essential part showing the configuration of a sixth embodiment of the ionization analyzer of the invention.

FIG. 19 is a longitudinal sectional view of an essential part showing the configuration of a seventh embodiment of the ionization analyzer of the present invention.

FIG. 20 is an explanatory diagram showing a configuration of a conventional ionization analyzer.

FIG. 21 is an explanatory diagram for explaining the problems of the conventional ionization analyzer.

[Explanation of symbols]

15 ... Ionization chamber, 18 ... Supply pipe, 20, 33 ... Hole, 2
1, 27, 28 ... Grid, 22, 32 ... Needle, 23 ... Moving device, 24 ... Voltage source, 31, 40, 50, 60, ... Capillary tube, 41 ... Ultrasonic transducer.

Claims (8)

[Claims] 1. An ionization analyzer for releasing ions of a sample contained in an electrolyte solution into air or vacuum in an ionization chamber, wherein a needle provided in the ionization chamber and a tip of the needle And an ion emitting means for emitting the ions by applying a voltage having a predetermined polarity corresponding to the charge polarity of the ions to the needle. Ionization analyzer. 2. The adhering means comprises a moving means for supplying the electrolyte solution into the ionization chamber and moving the needle to temporarily bring the tip thereof into contact with the electrolyte solution. Item 1. The ionization analyzer according to Item 1. 3. The needle is fixed in the ionization chamber, and the adhering means supplies a thin tube or a supply tube for supplying the electrolyte solution to the vicinity of the needle, and vibrates the thin tube or the supply tube for the electrolyte solution. 2. An ionization analyzer according to claim 1, further comprising: a vibrating unit that causes the electrolyte solution to adhere to the tip of the needle by moving the surface of the ionization analyzer. 4. The adhering means has a thin tube or a supply tube for supplying the electrolyte solution to the ionization chamber, and the needle has a tip portion protruding into the ionization chamber when moved in a predetermined direction. The ionization analyzer according to claim 1, wherein the ionization analyzer is provided so as to be movable back and forth in a thin tube or a supply tube. 5. The ionization analyzer according to claim 2, wherein the moving means vibrates the needle to temporarily bring its tip into contact with the electrolyte solution. 6. The ionization analyzer according to claim 3, wherein the vibrating means is an ultrasonic oscillator. 7. The ionization analyzer according to claim 1, wherein the needle has a surface coated with a dielectric film or a substance that repels an electrolyte solution. 8. The ionization analyzer according to claim 1, wherein the ion emitting means has a structure for applying a voltage to the needle or supplying a gas to the needle.