JP2000164169A - Mass spectrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance measuring accuracy by measuring a parameter of plasma, and performing mass spectrometry on an ion of a sample ionized by a plasma ion source. SOLUTION: An atomized sample solution is introduced to a sample introducing pipe 4, and then, to plasma 10 through an ion source 5 to be ionized. In the plasma 10, a parameter such as a temperature and density is measured by a measuring instrument 24. A signal obtained from the measuring instrument 24 is sent to either of an atomizing part 3, a plasma gas supply part 6, a microwave generating part 8, a power source 18 and a mass spectrometer control part 20 via a signal line 22' to control the ion source 5 and a mass spectrometer 19. For example, a plasma temperature is measured by the measuring instrument 24, and when the plasma temperature lowers, output of the microwave generating part 8 is enhanced to prevent reduction in ionizing efficiency to improve quantitatively determining accuracy of a sample. When plasma electric potential changes, an ion optical system 17 and the mass spectrometer 19 are controlled by the power source 18 and the mass spectrometer control part 20 on the basis of the signal of the measuring instrument 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention belongs to the field of analytical chemistry, and relates to a plasma ionization mass spectrometer.

[0002]

2. Description of the Related Art Plasma ionization mass spectrometry, in which a sample is introduced into plasma generated at atmospheric pressure and the obtained ions are taken in a vacuum to perform mass analysis, is known as a highly sensitive elemental analysis method. The most common device is an Inductively Coupled Plasma-Mass
Spectrometer; hereinafter referred to as ICP-MS). Plasma is generated using a high frequency of about 20 MHz, and a sample is introduced into the plasma to generate ions. The generated ions are taken into a vacuum through the pores and subjected to mass spectrometry. Details of ICP-MS are described in, for example, "Bunseki, 199
6 years, No. 5, p. 342 ".

In the ICP-MS, since argon is used as a gas for generating plasma, a large amount of matrix ions, such as Ar ⁺ and ArO ⁺ , originating from argon are generated. Therefore, there is a problem that it is difficult to detect Ca ⁺ , Fe ^{+, and the} like having a mass close to those of the matrix ions.

Therefore, a microwave induction plasma mass spectrometer (Microwave In
duced Plasma-Mass Spectrometer; MIP-MS below
) Was developed. In the MIP, a high energy density can be obtained by concentrating energy in a narrow space, so that nitrogen or helium can be used as a plasma gas, and a matrix caused by argon ions can be eliminated. Therefore, substances such as calcium and iron can be analyzed with high sensitivity by MIP-MS. The prior art of MIP-MS is described in, for example, JP-A-1-309300.

[0005] These plasma ionization mass spectrometers such as ICP-MS and MIP-MS are widely used in fields such as environmental analysis. As an example, a schematic diagram of a conventional MIP-MS is shown in FIG.
Shown in

[0006] The sample solution is sent from the sample solution tank 1 to the atomizing section 3 via the pipe 2. The atomizing unit 3 atomizes the sample solution using, for example, an atomizing gas supplied from an atomizing gas supply unit (not shown). The atomized sample solution becomes fine droplets and is introduced into the plasma ion source 5 through the sample introduction tube 4. The ion source 5 has a plasma gas supply section
A plasma gas such as nitrogen is supplied from 6 through a gas pipe 7 or the like. Microwave power is further sent to the ion source 5 from a microwave generation unit 8 via a microwave transmission circuit (such as a waveguide) 9. With this microwave power,
The plasma gas is ionized and plasma 10 is generated.

[0007] The fine droplets generated from the sample solution are introduced into the plasma 10 and exposed to the high temperature of the plasma. The droplet is vaporized in a short time, and the substance contained in the droplet is atomized and further ionized. The ions of the sample substance generated in this manner are supplied to the first pore 11 and the evacuation system.
Through the differential pumping section 13 evacuated at 12 and the second pores 14, it is taken into the high vacuum section 16 evacuated by the vacuum evacuating system 15. The ions taken into the high vacuum section 16 are orbitally converged by the ion optical system 17, and then sent to the mass analyzer 19 where they are subjected to mass analysis.

The ion optical system 17 is controlled by a power supply 18, and the mass analyzer 19 is controlled by a mass analyzer controller 20. The ions selected by mass are detected by the detector 21, and the detected signal is sent to the data processing device 23 via the signal line 22 for processing. When photons from the plasma reach the detector 21, they are detected as random noise and reduce the detection sensitivity of the apparatus.
Are often devised to block photons.

[0009]

In a plasma ionization mass spectrometer, a sample is ionized by a thermal action in the plasma, and the ionization efficiency of the sample differs depending on the state of the plasma. Parameters representing the state of the plasma (hereinafter referred to as plasma parameters) include an electron temperature, an ion temperature, a plasma density (the electron density and the ion density are almost equal in the plasma), a plasma potential, and the like. The plasma parameter changes depending on the position in the plasma, and for example, has different values at the center and the outer periphery of the plasma.

Therefore, in order to analyze the sample ions with high sensitivity, the position of the ion source (that is, the positional relationship between the plasma and the first pore) and the output of the high-frequency power supply are determined based on the signal obtained by the detector. Had to be adjusted. In particular,
The operation of moving the position of the ion source little by little while introducing the standard sample into the ion source, and searching for a place where the intensity of the standard sample ion becomes maximum was performed. In a commercially available device, this adjustment operation is often performed automatically by a control program.

However, since the above adjustment is performed using a standard sample prior to the measurement of the actual sample, the adjustment may be different from the optimum analysis conditions of the actual sample. In particular, when the flow rate of the sample solution or the composition of the solvent changes between the standard sample and the actual sample, the plasma parameters may change. For example, when the solution flow rate of the actual sample is larger than the time point adjusted using the standard sample, more droplets are introduced into the ion source, so that the plasma temperature decreases and the ionization efficiency of the sample decreases. . For this reason, if the quantification of the actual sample is performed based on the calibration curve created using the standard sample, the accuracy of the measurement result may be deteriorated.

Recently, for the purpose of chemical form analysis, that is, analysis according to the existence state of a sample substance in a solution, separation means in a liquid phase such as liquid chromatography, ion chromatography, and capillary electrophoresis, and a plasma ionization mass spectrometer have been proposed. The use of direct connection is increasing. In the liquid phase separation means, a so-called gradient mode in which the composition of the mobile phase solvent is changed with time in order to increase the separation efficiency may be used. When the composition of the solvent changes, the diameter and the like of the droplet generated in the atomization unit 3 change, and there is a possibility that the plasma parameters such as the plasma temperature change. As in this example, there is a problem that the accuracy of the obtained result is deteriorated because the ion generation efficiency is affected with time under the analysis condition in which the plasma parameter may change in a series of measurement operations. .

An object of the present invention is to increase the measurement accuracy in a plasma ionization mass spectrometer.

[0014]

According to the present invention, there is provided a plasma ion source for ionizing a sample with plasma, a measuring instrument for measuring the parameters of the plasma, and a mass spectrometer for ionizing the sample ionized by the plasma ion source. The object is achieved by a mass spectrometer comprising a mass spectrometer for analysis.

[0015]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. The sample solution is sent from the sample solution tank 1 to the atomization unit 3 via the pipe 2. The atomizing unit 3 atomizes the sample solution using, for example, an atomizing gas supplied from an atomizing gas supply unit (not shown). The atomized sample solution becomes fine droplets and is introduced into the plasma ion source 5 through the sample introduction tube 4.

A plasma gas such as nitrogen is supplied to the ion source 5 from a plasma gas supply unit 6 via a gas pipe 7 or the like. Microwave power is further sent to the ion source 5 from a microwave generation unit 8 via a microwave transmission circuit (such as a waveguide) 9. With this microwave power, the plasma gas is ionized and plasma 10 is generated. Fine droplets generated from the sample solution are introduced into the plasma 10 and exposed to the high temperature of the plasma. The droplet is vaporized in a short time, and the substance contained in the droplet is atomized and further ionized.

The ions of the sample substance generated in this manner are passed through the first pore 11, the differential pumping section 13 evacuated by the vacuum pumping system 12, and the second pore 14, and are passed through the vacuum pumping system 15. It is taken into the evacuated high vacuum section 16. The ions taken into the high vacuum section 16 are orbitally converged by the ion optical system 17, and then sent to the mass analyzer 19 where they are subjected to mass analysis. Ion optics 17
Is controlled by a power supply 18, and the mass analyzer 19 is controlled by a mass analyzer controller 20. The ions selected by mass are detected by the detector 21, and the detected signal is sent to the signal line.
The data is sent to the data processing device 23 via the processing unit 22 and processed.

The parameters such as temperature and density of the plasma 10 are measured by a measuring device 24. The signal obtained from the measuring device 24 is sent to any of the atomizing unit 3, the plasma gas supply unit 6, the microwave generation unit 8, the power supply 18, and the mass spectrometer control unit 20 via the signal line 22 ', Control the ion source and mass spectrometer according to the signal.

Next, the effect of the plasma parameter on the measurement will be described. When the plasma temperature (generally representing electron temperature) decreases, the ionization efficiency of an element having a high ionization potential decreases. The plasma potential is related to the energy of ions in the high vacuum section. Therefore, when the plasma potential fluctuates, the ion transmittance in the ion optical system changes, and when a quadrupole type is used as the mass analyzer, the ion transmittance and mass resolution of the mass analyzer are affected. When an ion trap type mass analyzer is used, the ion confinement efficiency changes.

As described above, when the plasma parameters change, the number of ions that finally reach the detector changes even when a sample of the same concentration is used, and the quantitativeness of the measurement result deteriorates.

According to the apparatus of the present invention, for example, when the plasma temperature is measured by the measuring device 24 and it is found that the plasma temperature has dropped, the output of the microwave generator 8 is increased to increase the predetermined temperature. Raise the temperature to This allows
A decrease in ionization efficiency can be prevented, and the accuracy of sample quantification is improved. The plasma temperature can also be controlled by changing the atomization conditions of the atomization unit 3 (for example, the flow rate of gas used for atomization) and changing the flow rate of the plasma gas in the plasma gas supply unit 6.

When the plasma potential changes, a measuring instrument
The ion optical system 17 and the mass analyzer 19 are controlled by the power supply 18 and the mass analyzer controller 20 based on the 24 signals. In particular,
For example, the voltage applied to the electrodes constituting the ion optical system may be controlled by the power supply 18 so that the ion transmittance of the ion optical system 17 is constant.

FIG. 2 is a diagram for explaining the embodiment of the present invention in more detail, and shows a main part of a mass spectrometer provided with a so-called Langmuir probe as a plasma parameter measuring device.

The microwave is sent to an ion source 5 composed of an inner conductor 25 and an outer conductor 26. A torch 27 to which a plasma gas and an atomizing gas are supplied is attached to the inner conductor 25 by a stopper 28. Due to the microwave power, a strong electric field is generated in a gap between the inner conductor 25 and the outer conductor 26, and the plasma gas is ionized to generate the plasma 10.

The sample is carried to the plasma 10 by the atomizing gas, and is ionized by the heat of the plasma 10. The generated ions are taken into the vacuum part via the pores 11 and 14 and analyzed.

The tip of the probe 29 is disposed in the plasma 10. If the probe is inserted directly into the plasma generated at atmospheric pressure, the probe may be melted by heat due to the very high density. As shown in FIG.
Since it also enters the differential exhaust unit 13 through the pores 11, when it is difficult to perform measurement under the atmospheric pressure, the measurement may be performed in the differential exhaust unit 13. The probe 29 is held by the differential pumping section 13 by the insulating holding section 30. In order to accurately measure the plasma density, the probe 29 may be covered with an insulating tube 31 except for the tip.

When a voltage is applied to the probe 29 from the probe power supply 32, a current flows according to the applied voltage. By analyzing this current-voltage characteristic, the electron temperature, plasma density, floating potential, plasma potential, and the like of the plasma can be known. The ion source and the mass spectrometer are controlled based on the obtained measurement results.

In the above-described Langmuir probe measurement, the electron saturation current or the ion saturation current that gives information on the plasma density may be monitored without analyzing the current-voltage characteristics and grasping the detailed plasma parameters. For example, as the voltage applied to the probe is reduced, the current flowing through the probe does not depend much on the voltage when the voltage exceeds a certain value (usually about -20 V). The current at this time is called an ion saturation current. Since the ion saturation current is proportional to the plasma density, the plasma density can be indirectly known by measuring the ion saturation current. As the probe 29, an emissive probe for measuring a space potential may be used instead of the Langmuir probe.

There are various methods for measuring the plasma parameters other than the method using the probe described above. FIG.
An example in which plasma density is measured by irradiating a microwave will be described.

The microwave 10 is radiated by the microwave radiating antenna 33 to the plasma 10 generated by the ion source 5. Due to the characteristics of the propagation mode of the electromagnetic wave in the plasma, the phase of the microwave received by the microwave receiving antenna 34 is shifted as compared with the case where there is no plasma, and the amount of the shift depends on the plasma density. Therefore, it is possible to know the density of the plasma 10 by introducing the microwave branched as a reference and the microwave received by the microwave receiving antenna 34 into the microwave interferometer and examining the phase difference. it can.

The density of the plasma can also be known by measuring the emission intensity of the plasma. Plasma is an ionized gas, but the ionization ratio of ions and electrons is low, and most of the plasma exists as an excited neutral gas. A gas in an excited state emits photons when it transitions to a more stable state. In a plasma having a low ionization degree, the emission intensity depends on the plasma density. Therefore, the plasma density can be measured by using an emission intensity meter.

In the present invention, highly accurate measurement is enabled by controlling the ion source and the mass spectrometer in accordance with the fluctuation of the plasma parameter. There is also a method of providing a mechanism for giving a warning. As the warning method, it is effective to display a message on a monitor screen of a control device, such as a sound, lighting of a lamp, and the like. The measurer can recognize that the obtained data is unreliable by issuing the warning. Also, when the measurement results are output from the data processing device, the measured plasma parameters are also output at the same time, which is useful for reviewing the data later. If the plasma parameters have changed compared to the normal measurement,
Measures such as confirming data by re-measurement can be taken.

In practicing the present invention, the plasma ion source is effective in either an inductively coupled plasma (ICP) or a microwave induced plasma (MIP). Further, the present invention is effective regardless of the type of mass spectrometer, and can be implemented by, for example, a double focusing type, a quadrupole type, a time-of-flight type, a Fourier transform ion cyclotron resonance type, a quadrupole ion trap type, or the like.

For reference, an embodiment of a plasma ionization mass spectrometer provided with an ICP ion source and a quadrupole ion trap mass analyzer will be described with reference to FIG.

The ICP torch 51 has a triple tube structure. The atomizing gas is sent to the center, and fine droplets of the sample solution generated by the atomizer are introduced. A plasma gas (mainly argon) for generating plasma is flowed around the outer periphery of the atomizing gas. Further, a sheath gas for generating a predetermined airflow in the torch 51 and maintaining the plasma is introduced into the outer peripheral portion thereof.

An induction coil 52 is provided on the outer periphery of the tip of the torch 51.
Are arranged, and high-frequency power is supplied. An electric field is induced at the tip of the torch 51 by the AC magnetic field generated by the induction coil, and the electric field ionizes the plasma gas to generate the plasma 10. The droplets introduced into the plasma by the atomizing gas are exposed to the high temperature of the plasma. The droplet is vaporized in a short time, and the substance contained in the droplet is atomized and further ionized.

The ions of the sample substance thus generated are taken into the high vacuum section through the first pore, the differential pumping section evacuated by the vacuum pumping system 12, and the second pore. Electrode 53 with first pore opening and electrode 54 with second pore opening
Are connected to power supplies 101 and 102, respectively, so that a voltage can be applied. The first pore and the second pore may have the same potential.

Although various means can be used for measuring the plasma parameters, a configuration using a Langmuir probe will be described as a representative. The tip of the probe 29 is inserted into the plasma 10 that has entered the differential pumping section. Although the probe may be inserted directly into the plasma generated at atmospheric pressure, the probe may be melted by heat because the density and temperature of the plasma are usually very high in this portion. Since the plasma also enters the differential pumping section through the first pores, in this embodiment, a probe is provided in the differential pumping section as shown in FIG. To accurately measure the plasma density, the probe 29 is preferably covered with an insulating tube except for the tip.

When a voltage is applied from the probe power supply 32 to the probe 29, a current flows according to the applied voltage. By analyzing this current-voltage characteristic, the electron temperature and density of the plasma,
Plasma parameters such as plasma potential can be measured.

The ions taken into the high vacuum section are converged by the Einzel lenses (55, 56, 57) and pass through a slit electrode 58 having a small opening. Most of the droplets not completely vaporized in the plasma are removed by the slit electrode 58.

Here, in daily cleaning, the gate valve 59 may be closed and the plasma side of the gate valve 59 may be disassembled for cleaning. Since dirt mainly adheres to the periphery of the first pores and the slit electrode 58, cleaning of this portion makes it possible to perform cleaning very easily. By providing the gate valve 59, the apparatus can be cleaned while evacuating the high vacuum section in which the mass spectrometer is arranged, and the time until remeasurement can be started can be reduced. This gate valve 59 is normally electrically grounded.

The trajectory of the ion beam that has passed through the slit electrode 58 expands at the gate valve 59, but the inner cylinder electrode 61 having an opening and the outer cylinder electrode 62 disposed outside the inner cylinder electrode 61 have an opening.
, And the trajectory is converged again. Since a voltage is applied to the electrodes (61, 62) constituting the ion guide, a shield electrode 60 is provided between the gate valve and the ion guide to prevent the ions from being affected by the electric field even when passing through the gate valve 59. Is arranged.

After passing through the ion guide, the traveling direction of the ions is deflected by a deflector composed of a deflector case 63, a deflector outer electrode 64, and a deflector inner electrode 65. This is because when photons generated in the plasma reach the ion detector, they are detected as noise and affect the lower detection limit of the device.
This is to separate the photon orbit by bending the ion orbit. In order to prevent the photon from irregularly reflecting and reaching the ion detector, the deflector case 63 and the deflector outer electrode 64 have
Each of the openings (66, 67) is provided so that photons that have traveled straight pass through the deflector. The ions that have passed through the deflector are converged by the lens electrode 68, and then sent to the quadrupole ion trap mass analyzer via the gate electrode 69.

The quadrupole ion trap mass analyzer comprises a pair of end cap electrodes (70, 72) and a ring electrode 71. The gate electrode 69 is provided for controlling the timing of the incidence of ions on the quadrupole ion trap mass analyzer.

First, in order to generate an ion confinement potential inside the quadrupole ion trap mass spectrometer,
A high-frequency voltage is applied to the ring electrode 71. At this timing, the voltage applied to the gate electrode is reduced so that ions can pass through the gate electrode.

Helium is supplied from a helium gas supply device (not shown) to the inside of the quadrupole ion trap mass spectrometer, and is maintained at a pressure of about 1 mTorr. Ions that have entered the quadrupole ion trap mass analyzer lose their energy by colliding with helium gas and are trapped by the ion confinement potential. After accumulating ions that have entered for a predetermined time (typically 50 milliseconds), the process proceeds to the stage of analyzing the mass of the ions.

At this timing, the voltage applied to the gate electrode 69 is increased so that ions cannot pass through the gate electrode. Next, by gradually increasing the amplitude of the high-frequency voltage applied to the ring electrode 71, the orbit becomes unstable in ascending order of the value obtained by dividing the mass of the ion by the charge of the ion, and the end cap electrodes 70, 72 Is discharged out of the mass spectrometer through an opening provided in the mass spectrometer. The ejected ions are detected by the ion detector 21. After the mass analysis, the voltage applied to the ring electrode 71 is turned off to eliminate the ion confinement potential, thereby removing ions remaining inside the mass analyzer.

By repeating such a series of operations, a mass spectrum of the sample substance is obtained.

At the stage of analyzing the mass of ions, the end cap electrode 70,
A high frequency signal of a predetermined frequency may be applied between the 72 to assist the discharge of ions. Also, except for the stage of analyzing the mass of the ions, applying a high voltage to the ion stop electrode,
Prevent stray ions from reaching detector 21.

The plasma parameters measured using the probe 29 are used for controlling an ion source, an ion optical system, and a quadrupole ion trap mass analyzer. Less than,
A typical example of a control method when the plasma parameter measured by the probe 28 changes will be described.

The relationship between each plasma parameter and the optimum analysis condition may be constructed as a database in an apparatus controller (not shown), and the apparatus may be controlled based on the database.

(Change in Plasma Temperature) When the plasma temperature (generally representing electron temperature) changes, the ionization efficiency of an element having a high ionization potential changes. To control the plasma temperature, the plasma generation conditions such as the spray gas flow rate, the plasma gas flow rate, the sheath gas flow rate, and the high-frequency power applied to the induction coil are adjusted. For example, when the plasma temperature decreases, the high-frequency power is set high, or the flow rate of the plasma gas is reduced, for example. Conversely, if the plasma temperature is too high, divalent ions of an element having a low second ionization potential are generated, and this divalent ion may cause a problem in measurement. In this case, the high frequency power is set low or the flow rate of the plasma gas is increased.

(Change in Plasma Density) When the plasma density measured by the probe arranged in the differential pumping section changes, it is necessary to consider not only the possibility that the plasma parameter has changed but also the dirt and clogging of the first pore. No. When the plasma parameters are changed, the plasma generation conditions may be controlled as described above, and the plasma generation conditions may be adjusted so that a predetermined density of plasma can be generated. If the specified plasma density cannot be obtained even after controlling the plasma generation conditions, it is possible to judge that the state of the plasma flowing into the differential exhaust unit has changed due to dirt or clogging of the pores. It is preferable to promote the cleaning of the first pores.

(Change in Plasma Potential) When the plasma potential changes, the energy of ions passing through the vacuum vessel changes. For this reason, the ion transmission conditions of the ion optical system must be adjusted. Specifically, Einzel lenses (55, 56, 57), slit electrode 58, shield electrode 6
0, ion guide (61, 62), deflector (63, 64, 65),
Some or all of the voltage values applied to each of the electrodes constituting the lens electrode 68 are set so that the ion transmittance increases in accordance with the measured plasma potential.

In the case of a quadrupole ion trap mass analyzer, the efficiency of confining ions inside the mass analyzer changes depending on the energy of the ions at the time of incidence. The energy of the ions entering the mass analyzer depends on the kinetic energy of the ions passing through the second pore affected by the plasma potential and the potential difference between the electrode 54 opening the second pore and the end cap electrode 70. . Therefore, the measurement accuracy can be improved by controlling the voltage applied to the electrode 54 in which the second pore is opened using the power supply 102 in accordance with the value of the measured plasma potential.

[0056]

According to the present invention, since the ion source and the mass spectrometer are controlled while measuring the plasma parameters, the ionization efficiency and the ion transmittance can be kept constant under various analysis conditions. Accuracy has improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an interface unit including a probe according to one embodiment of the present invention.

FIG. 3 is a perspective view showing an interface including a microwave interferometer according to one embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a mass spectrometer provided with an inductively coupled plasma ion source and an ion trap mass analyzer according to one embodiment of the present invention.

FIG. 5 is a block diagram of a conventional plasma ionization mass spectrometer.

[Explanation of symbols]

1 ... Sample solution tank, 2 ... Piping, 3 ... Atomizer, 4 ... Sample introduction pipe,
5 ... Ion source, 6 ... Plasma gas supply unit, 7 ... Gas piping, 8
... Microwave generator, 9 ... Microwave transmission circuit, 10 ... Plasma, 11 ... First pore, 12 ... Vacuum exhaust system, 13 ... Differential exhaust unit, 14 ... Second pore, 15 ... Vacuum exhaust system, 16 ... High vacuum section, 17
... Ion optical system, 18 ... Ion optical system power supply, 19 ... Mass analyzer, 20 ... Mass analyzer controller, 21 ... Detector, 22, 22 '... Signal line, 23 ... Data processor, 24 ... Measuring instrument, 25 ... inner conductor, 26 ... outer conductor, 27 ... torch, 28 ... stopper, 29 ... probe, 30 ... insulation holder, 31 ... insulation tube, 32 ... probe power supply, 33 ... microwave radiation antenna, 34 ... microwave reception Antenna, 51: Torch for ICP, 52: Induction coil, 53: Electrode with open first pore, 54: Electrode with open second pore,
55: Einzel first electrode, 56: Einzel second electrode, 57: Einzel third electrode, 58: Slit electrode, 59
... gate valve, 60 ... shield electrode, 61 ... inner cylinder electrode, 62
... outer cylinder electrode, 63 ... deflector case, 64 ... deflector outer electrode,
65… Deflector inner electrode, 66, 67… Aperture, 68… Lens electrode,
69 ... gate electrode, 70, 72 ... end cap electrode, 71 ... ring electrode, 73 ... ion stop electrode, 101, 102, 103, 1
04, 105, 106, 107, 108, 109, 110, 111, 112, 113, 1
14, 115, 116, 117, 118 ... power supply.

Continuation of the front page (72) Inventor Minoru Sakairi 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo F-term (reference) 2G043 AA01 CA03 DA05 EA08 GA11 GB05 JA01 LA07 MA06 5C038 GG09 GH02 GH15 HH02 HH26

Claims (6)

[Claims] 1. A plasma ion source for ionizing a sample with plasma, a measuring instrument for measuring parameters of the plasma, and a mass analyzer for mass analyzing ions of the sample ionized by the plasma ion source. A mass spectrometer comprising: 2. The mass spectrometer according to claim 1, wherein said plasma ion source is controlled based on a signal obtained by a measuring instrument for measuring parameters of said plasma. 3. The mass spectrometer according to claim 1, wherein the mass spectrometer is controlled based on a signal obtained by a measuring instrument for measuring a parameter of the plasma. 4. The mass spectrometer according to claim 1, wherein the measuring device for measuring the parameters of the plasma includes a probe. 5. The mass spectrometer according to claim 1, wherein the measuring device for measuring the parameters of the plasma includes a microwave interferometer. 6. The mass spectrometer according to claim 1, wherein the measuring device for measuring the parameters of the plasma includes an emission intensity measuring device.