JP2010197080A - Induction coupling plasma analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably produce plasma by fixing the relative position of a plasma torch and a high-frequency induction coil at a predetermined position. <P>SOLUTION: This induction coupling plasma analyzer includes the plasma torch 4 into which a plasma forming gas and an atomized sample are introduced and an induction coil 6 applying high-frequency voltage to the plasma torch 4. The induction coil 6 is fixed by an induction coil presser 11 equipped with a cavity permitting the plasma torch 4 to pass. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to an inductively coupled plasma analyzer (hereinafter referred to as an ICP device) such as an inductively coupled plasma emission spectrometer (ICP-AES), an inductively coupled plasma mass spectrometer (ICP-MS), and more particularly to plasma of an ICP device. This relates to the generation unit.

  FIG. 2 shows an example of a schematic configuration diagram of a plasma generation unit of a conventional ICP device. The plasma generator 1 includes a plasma torch 4 that generates inductively coupled plasma, a plasma torch holding member 5 for detachably fixing the outermost tube of the plasma torch 4, and an induction coil 6 that applies a high-frequency voltage to the plasma torch 4. And a positioning projection 19 for positioning the mounting position of the plasma torch 4.

  The positioning convex portion 19 is a tubular member that is externally fitted at a predetermined position of the plasma torch 4 and integrated with the plasma torch 4. When the plasma torch 4 is positioned at the predetermined position, the positioning convex portion 19 is It is in contact with and fixed to the plasma torch holder 5.

  A high frequency electromagnetic field formed by applying a high frequency voltage to the induction coil 6 excites a plasma gas composed of argon gas flowing in the plasma torch 4 to form plasma A.

The sample ejected into the plasma torch 4 together with a carrier gas made of argon gas from another inlet is excited by the plasma A and atomized to emit light. (For example, see Patent Document 1)
A qualitative quantitative measurement of an element in a sample has been performed by separating the emission spectrum of the plasma with a spectroscope or separating the mass with a mass spectrometer.

Japanese Patent Laid-Open No. 11-40100

  However, the conventional ICP device described above has the following problems.

  That is, in the conventional technique, the relative position of the plasma torch with respect to the plasma torch holder can be easily positioned, so that the plasma torch can be easily and accurately attached to the predetermined position, but the relative position of the induction coil and the plasma torch is stable. Therefore, since the positioning cannot be performed, there is a problem that the plasma is difficult to ignite, does not ignite, or becomes unstable even if the plasma is ignited.

  The present invention has been made in consideration of such circumstances, and the object of the present invention is to make it possible to easily attach a plasma torch and an induction coil at a predetermined position so that plasma ignition and Another object is to provide an ICP device capable of stabilizing the plasma state.

  In order to achieve the above object, the present invention provides the following means.

  An ICP apparatus according to the present invention includes a tubular plasma torch into which a plasma gas and an atomized sample are introduced, an induction coil for applying a high frequency voltage to the plasma torch, and a plasma generated by the high frequency voltage of the induction coil. The induction coil is provided with a detector for detecting the emission of light, and an analysis processing unit for analyzing the spectrum of the detected emission, and the induction coil is an induction coil holder having a hollow cylindrical cavity through which the plasma torch passes. It was fixed with.

  Alternatively, by making the shape of the induction coil retainer cavity substantially the same as the outer peripheral shape of the plasma torch, the plasma torch outer circumference and the induction coil are relatively relative to the tubular cross-section (short axis) direction of the plasma torch. The positional relationship can be fixed.

  Alternatively, by fixing the plasma torch so that the plasma torch tip on the side from which the plasma is emitted and one surface of the induction coil holding cavity are substantially on the same plane, the long axis of the plasma torch The relative positional relationship between the plasma torch and the induction coil can be fixed with respect to the direction.

  In addition, the induction coil retainer is made of a material having a relative dielectric constant similar to that of air, such as extruded polystyrene.

  According to the ICP device of the present invention, the relative position between the plasma torch and the high-frequency induction coil can be easily attached to a predetermined position, so that the effect of stabilizing plasma ignition can be obtained.

It is a block diagram which shows 1st Embodiment of the ICP apparatus which concerns on this invention. It is a block diagram which shows an example of the plasma torch periphery part of the conventional ICP apparatus.

  A first embodiment of an ICP (inductively coupled plasma analyzer) apparatus according to the present invention will be described below with reference to FIG.

  FIG. 1 shows an example of a schematic configuration diagram of an ICP device of the present embodiment.

  The ICP apparatus of this embodiment is roughly composed of a sample introduction unit 2, a plasma generation unit 1, and a detection unit 3. In the sample introduction unit 2, the liquid sample in the sample container 7 is sucked by flowing an argon gas serving as a carrier gas in the nebulizer 9. Then, the sample sucked into the nebulizer 9 is discharged into the spray chamber 10 to be atomized. In the plasma generation unit 1, a plasma gas such as argon, an atomized sample, and a carrier gas are passed through the plasma torch 4, and a high frequency voltage is applied to the induction coil 6 provided around the plasma torch 4. Then, plasma is generated to excite and ionize the sample. And in the detection part 3, the plasma light emission containing the ionized sample produced | generated on the opposite side to the sample introduction part 2 side of the plasma torch 4 of the plasma generation part 1 is detected with detectors, such as a spectrometer and a mass spectrometer. The analysis control unit 15 performs qualitative quantitative analysis of the element of the sample from the detected wavelength and mass.

  The plasma torch 4 has a concentric cylindrical triple tube structure made of quartz, and a sample gas tube (inner tube) 12 for a sample introduced together with a carrier gas such as argon (Ar) gas is located at the center thereof. The auxiliary gas pipe (middle tube) 13 for controlling the vertical position of the plasma is surrounded by a plasma gas pipe (outer tube) 14 for flowing a plasma gas around the auxiliary gas pipe (middle tube) 13. It has become. The plasma torch 4 is fixed in contact with the plasma torch holder 5.

  Furthermore, the induction coil 6 is wound around the outside of the plasma gas tube 14 by the induction coil holder 11 and wound three turns.

  The induction coil retainer 11 is desirably made of a material having a relative dielectric constant close to air. For example, the induction coil retainer 11 is made of Styrofoam (registered trademark), which is one of extruded polystyrene, having a relative dielectric constant close to air and high heat resistance. An inductive coil 6 surrounding the induction coil 6 at a predetermined position and having a hollow cylindrical shape substantially the same as the outer shape of the plasma gas tube 14 is integrally molded.

  Furthermore, by fixing the surface of the induction coil holder 11 on the outlet side of the plasma torch 4 and the surface on the outlet side of the plasma gas tube 14 at a position where they are on the same plane, the relative relationship between the induction coil 6 and the plasma torch 4 is increased. The position can be fixed at a predetermined position.

  The high frequency electromagnetic field formed by the induction coil 6 ionizes the argon gas flowing through the plasma gas tube 14 to form plasma.

  When the carrier gas flows through the nebulizer 9, the sample is sucked up from the sample container 7 containing the liquid sample through the tube 8 according to the spraying principle, atomized, and blown into the spray chamber 10. Then, the atomized sample passes through the sample gas pipe 12 together with the carrier gas and is jetted into the plasma gas pipe 14 from the tip of the sample gas pipe 12.

  The sample ejected from the tip of the sample gas tube 12 is excited by this plasma to emit light.

  The plasma emission including the excited sample is dispersed by a sequential type spectroscope, which is the detector 16, and qualitative and quantitative measurement of elements in the sample is performed.

  A sequential spectrometer is a type called a monochromator, which uses a photomultiplier tube (PMT) and rotates the diffraction grating with a stepping motor to measure the wavelength position of the element one after another. .

  The analysis control unit 15 creates a mass spectrum from the data from the spectroscope 16, performs qualitative / quantitative analysis of the elements in the sample, and displays the result as a mass spectrum or numerical value on a display (not shown). It is trying to display.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in this embodiment, a sequential spectrometer is used as the detector, but a multi-type spectrometer or a mass spectrometer may be used. Multichannel spectrometers measure multiple wavelengths simultaneously using a spectroscopic system called a polychromator and a two-dimensional detector such as a charge-coupled device (CCD). Moreover, a mass spectrometer measures by separating the ionized sample for every mass to charge ratio.

  In the embodiment, a fassel-type triple tube torch is used, but the present invention is not limited to this, and a quadruple tube torch may be used.

  In the present embodiment, the outer periphery of the plasma torch 4 is fixed by the induction coil presser 11 so as to surround the entire induction coil 6 arranged, but this is not limitative. For example, a part of the turn part of the induction coil 6 may be fixed and a part of the outer shape of the plasma torch 4 may be supported by using a fluororesin material such as polytetrafluoroethylene.

  Further, a bonnet made of quartz or the like serving as a shield for preventing discharge may be provided between the induction coil holder 11 and the plasma torch 4. In this case, the surface of the induction coil holder 11 on the outlet side of the plasma torch 4 may be aligned with the position of the bonnet.

  In order to prevent discharge between the induction coil holder 11 and the induction coil 6, an insulating layer such as quartz may be provided therebetween.

DESCRIPTION OF SYMBOLS 1 Plasma production part 2 Sample introduction part 3 Detection part 4 Plasma torch 5 Plasma torch press 6 Induction coil 7 Sample container 8 Tube 9 Nebulizer 10 Spray chamber 11 Induction coil press 12 Sample gas pipe 13 Auxiliary gas pipe 14 Plasma gas pipe 15 Analysis Control unit 16 Detector

Claims (5)

A plasma torch into which a plasma gas and atomized sample are introduced;
An induction coil for applying a high frequency voltage to the plasma torch;
The sample is ionized by the plasma generated by the high frequency voltage of the induction coil,
A detector for measuring the element in the ionized sample;
In an inductively coupled plasma analyzer comprising:
The inductively coupled plasma analyzer is characterized in that the induction coil is fixed by an induction coil holder having a cavity through which the plasma torch is passed. The inductively coupled plasma analyzer according to claim 1,
The plasma torch is cylindrical,
The inductively coupled plasma analyzer is characterized in that the shape of the induction coil holder cavity is substantially the same as the outer periphery of the cylindrical plasma torch. The inductively coupled plasma analyzer according to claim 2,
An inductively coupled plasma analyzer, wherein the plasma torch is fixed so that a tip portion of the plasma torch and one exit side of a cavity of the induction coil holder are substantially on the same plane. The inductively coupled plasma analyzer according to claim 1,
The inductively coupled plasma analyzer is characterized in that the induction coil retainer is made of a material having a relative permittivity equivalent to that of air. The inductively coupled plasma analyzer according to claim 4,
The inductively coupled plasma analyzer is characterized in that the induction coil retainer is made of extruded polystyrene.

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