JPH0843311A - ICP emission spectroscopy analyzer and optical sampling device - Google Patents

Abstract

PURPOSE:To provide a device for sampling emission caused by a sample as much as possible without being hindered by a plasma torch in an ICP (high frequency inductively coupled plasma) emission spectrophotometer. CONSTITUTION:A light sampling part 20 for sampling emission caused by a sample in a plasma torch to reflect it by means of a mirror 22 so as to induce it into a spectroscope 10 is arranged between a plasma torch 4 and the spectroscope 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ICP (high frequency inductively coupled plasma) optical emission spectrometer.

[0002]

2. Description of the Related Art Generally, in an ICP emission spectroscopic analyzer,
The solution sample is introduced into a plasma torch to cause the sample to emit light, and the light emitted from the sample is dispersed into spectral light of each element with a spectroscope, and then the intensity of each spectral light is measured and included in the sample. We conduct qualitative and quantitative analysis of each element.

An outline of a conventional ICP emission spectroscopic analyzer will be described below with reference to FIG. 3 (for details, see JP-A-63-1).
(Described in No. 35846), 1 is an IC
2 shows a P emission spectroscopic analyzer as a whole (partially omitted), 2 is a plasma flame, 3 is an induction coil for generating a high frequency magnetic field, 4 is a plasma torch for emitting plasma emission from a solution sample 5, and this plasma is The sample 5 to the torch is introduced by the carrier gas 6. In addition, 7 is a plasma gas and 8 is a cooling gas, and these gases are supplied through a flow control valve (not shown).

Reference numeral 9 is a light introducing tube from the plasma flame 2, and the radiated light taken in from this is dispersed by the spectroscope 10. The spectroscope 10 is, for example, a wavelength scanning spectroscope, and includes a vacuum chamber 11
Diffraction grating that splits the light taken in from the light introducing tube through the condenser lens 11 'provided in
12, a photodetector 13 such as a photomultiplier tube for detecting spectral light dispersed by the diffraction grating 12, and a reflection mirror 14,
It is composed of 15 mag. The light introducing tube 9 comprises a quartz tube 9'and a holding tube 9 ", one end of the quartz tube 9'is arranged at a position facing the plasma flame, and the holding tube 9" is also provided.
One end of is fixed to the outer wall of the vacuum chamber 11. Further, the purge gas 16 is introduced into the holding cylinder 9 ″ through a flow rate control valve (not shown).

Although the operation of the above-mentioned conventional apparatus is known, in brief description, the sample introduced into the plasma flame 2 becomes hot and emits light. The light is condensed on the spectroscope 10 by the condensing lens 11 'through the light introducing tube 9, and the diffraction grating 12
The light of the target element (wavelength) is spectroscopically analyzed by scanning
The value can be detected by the photodetector 13, so that the concentration of the target element in the sample can be known.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the CP emission spectroscopic analyzer, the light of the target element passes through the plasma flame and is taken into the light introducing tube, so that the light of the plasma flame is superposed on the light of the target element to analyze a particularly small amount of element. It was an obstacle to measurement.

[0007]

According to the present invention, an optical sampling section is provided between a plasma torch and a spectroscope so that light based on a sample is guided from the axis of the plasma torch to the spectroscope. The sampling section has a mirror for changing the optical path and a cooling section for preventing the temperature rise.

[0008]

Since the optical sampling section is provided as described above,
An optical sampling unit is inserted into the plasma flame, and the light accompanying the emission of the sample itself near the center of the plasma flame can be sampled and sent to the spectroscope, so only the light based on the sample can be taken out. The noise of the light due to the decrease is reduced, and accurate analytical measurement becomes possible. In addition,
Since the optical sampling section has a built-in mirror that changes the optical path, it is possible to extract light in any direction, and the overall size of the device can be reduced. It is possible to prevent the temperature from rising.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view (partially omitted) of an ICP emission spectroscopic analyzer according to the present invention.

In the figure, 2 is a plasma flame, which is caused by the induction coil of 3. Reference numeral 4 is a plasma torch, in which a mixed gas of the sample 5 and the carrier gas 6 is caused to flow in the central portion, and the periphery thereof is surrounded by the plasma gas 7 and the cooling gas 8.

Reference numeral 20 is an optical sampling section according to the present invention, and the tip portion 21 has, for example, a cone shape (funnel shape), is inserted into the plasma flame 2, and seems to be based on the sample 5. The portion of the light to be sampled is mainly sampled. A mirror 22 for bending the optical path by 90 degrees in this embodiment is provided inside the sampling section 20, and the light based on the sample is reflected by the mirror and bent by 90 degrees.
10 inputs.

The mirror 22 is supported by a support rod 23 and fixed on a cover plate 24. The reference numeral 25 denotes an exhaust hole formed in the cover plate 24, which serves to release gas at a high temperature due to plasma flame. As is clear from the above description, the heat from the plasma torch does not reach the spectroscope, and only the light is bent by the mirror and enters the spectroscope.

On the other hand, reference numeral 26 is, for example, a water circulation path provided in the optical sampling wall, and water is constantly circulated during use to cool the optical sampling section 20.

In this embodiment, the optical sampling section 20 is supported by the holding tube 9 "provided on the front surface of the spectroscope 10, so that the light sampled from the plasma flame 2 is reflected by the mirror. Reflected at a right angle at 22 and spectrometer 10
Will be incident on and will be spectrally analyzed.

At this time, since the light of the portion based on the sample in the plasma flame is sampled at the tip of the optical sampling section, that is, the light of the sample is directly taken out, so that the spectrum is separated as in the conventional case. It is possible to prevent a large amount of plasma flame light from being mixed as noise into the container, which improves the analysis accuracy.

Reference numeral 16 is a purge gas for purging the optical sampling section 20 and the holding cylinder 9 ".

2 (a) and 2 (b) schematically show the positional relationship between the plasma torch and the optical sampling section.
(a) is the same as FIG. 1, but in FIG. 1, the optical sampling unit 20 is moved closer to the lateral direction of the plasma flame 2 by making the holding cylinder and the optical sampling unit rotatable. Light emitted from the sample in the plasma plasma flame 2 can be sampled from the lateral direction.

Further, as is apparent from the above description, it goes without saying that the optical sampling section can be removed from the holding cylinder and the quartz tube can be connected as shown in FIG. 3 to perform the same measurement as in the conventional case. That is.

The following results were obtained by comparing the measurement results of the case of using the optical sampling section according to the present invention with those of the conventional method in terms of the sensitivity of several elements. Element name Mn Fe Pb Zn As Se Sensitivity increase rate (times) 31 30 9 20 2 2 FIG. 4 shows a configuration conceived in the process of reaching the present invention, in which the plasma torch 4 is laid down sideways, The same sampling cone (funnel) 21 as the tip of the optical sampling section described in the present invention is provided, and the spectroscope is provided behind it.
It has a configuration in which 10 are arranged. In addition, cooling water or the like is introduced into the sampling cone portion. Even with this configuration, it is possible to capture the light of the portion corresponding to the sample in the plasma flame by the sampling cone,
Since there is a spectroscope etc. on the axis of the plasma torch, it is not preferable for spectroscopic analysis because the hot air stream on the spectroscope side flows in, and since the plasma torch was laid down sideways, the fluctuation of the plasma flame was inevitably large, The detection result with stable accuracy was not obtained.

Furthermore, it was not possible to use the sampling cone and the spectroscope arranged above the plasma torch in an upright state because the influence of heat on the spectroscope located above is great.

On the other hand, in comparison with this method of FIG.
In the present invention described with reference to FIGS. 2 and 3, since the optical component is bent by the mirror and guided to the spectroscope, the thermal influence on the spectroscope can be reduced and the analysis accuracy can be improved. .

In the above description, the light is bent 90 degrees by the mirror, but it is obvious that the invention is not limited to this.

[0023]

EFFECT OF THE INVENTION Since the portion of the light in the plasma flame due to the sample can be selectively sampled and measured, the influence of the plasma flame itself is small and the analysis accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a main part embodiment of an ICP emission spectroscopic analyzer (partially omitted) according to the present invention.

FIG. 2 is a diagram illustrating a main part of a usage mode of the present invention.

FIG. 3 is a diagram illustrating a main part of a conventional ICP emission spectroscopic analyzer (partially omitted).

FIG. 4 is a view for explaining a main part of an ICP emission spectroscopic analyzer (partially omitted) in the process of conforming to the present invention.

[Explanation of symbols]

2 ... Plasma flame 4 ... Plasma torch 10 ... Spectrometer 20 ... Optical sampling unit 21 ... Tip (cone) 22 ... Mirror 26 ... Water circulation path

[Procedure amendment]

[Submission date] December 21, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: ICP emission spectroscopy analyzer and optical sampling device

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

According to the present invention, an optical sampling unit is provided between a plasma torch and a spectroscope so that light from a sample is guided from the axis of the plasma torch to a spectroscope for sampling. The sampling section has a mirror for changing the optical path and a cooling section for preventing the temperature rise. Furthermore, this invention
Optical sampling unit
It is configured as.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Further, as is apparent from the above description, it is needless to say that the optical sampling section can be removed from the holding cylinder and the quartz tube can be connected as shown in FIG. That is. Also this light sun
If the pulling unit is configured separately, the optical sampling device
Be placed.

Claims (1)

[Claims] 1. An apparatus having a plasma torch and a spectroscope for separating light from the plasma torch, wherein an optical sampling section is arranged between the plasma torch and the spectroscope, and the optical sampling section is arranged to detect the light from the plasma torch. An ICP emission spectroscopic analyzer comprising a mirror for changing an optical path and a cooling unit for preventing a temperature rise.