JPH04328450A - Plasma generating spectrometer - Google Patents

Abstract

PURPOSE:To obtain a plasma generating spectrometer having a torch which can inject fine particles in the center of a plasma erected at the center of a discharge tube. CONSTITUTION:There are provided a discharge tube 1, a torch 1b inserted into the discharge tube and an end of which is narrowed, and a cavity 5 which resonates microwaves and generates a microwave-induced plasma in the discharge tube. Moreover, an optical system which takes out and condenses the light generated from the microwave-induced plasma in the axial direction of the discharge tube 1, and a signal processing part 9 which splits the light condensed by the optical system to process the signals are provided. Accordingly, an element to be measured in a sample is detected.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a plasma emission spectrometer that is installed as a detector in an emission spectrometer that analyzes elements in a sample using microwave-induced plasma. The present invention relates to a plasma emission spectroscopic detector equipped with a torch capable of forming a plasma at the center of the plasma and injecting fine particles into the center of the plasma.

0002

BACKGROUND OF THE INVENTION Conventionally known emission spectroscopic detectors have only been experimentally manufactured and used in laboratories. For this reason, the present inventors developed an emission spectroscopic detector that is capable of highly sensitive detection and is easy to maintain.
The same applicant as the applicant of the present application filed an application on April 23, 1990 with the name of the invention "Emission spectroscopic detector" (Patent application No.
-107133, application publication number unknown).

However, in such an emission spectroscopic detector, the structure of the torch is made to match the inner diameter of the discharge tube, for example, the inner diameter of the discharge tube is 3.5 mm and the inner diameter of the torch is 2 mm. It was getting worse. For this reason, some of the fine particles supplied from the torch pass through the center of the plasma, while others pass through the edges of the plasma, which has an adverse effect on luminous efficiency.

0004

[Problems to be Solved by the Invention] The present invention has been made in view of the above situation, and its purpose is to create a plasma in the center of a discharge tube and to provide a torch that can inject fine particles into the center of the plasma. An object of the present invention is to provide a plasma emission spectroscopic detector.

[0005]

[Means for Solving the Problems] The present invention provides a plasma emission spectrometer detector in which a discharge tube, a torch inserted into the discharge tube and provided with an aperture at its tip, and microwaves are caused to resonate in a cavity. a cavity that generates microwave-induced plasma within the discharge tube; an optical system that extracts and focuses light emitted from the microwave-induced plasma in the axial direction of the discharge tube;
The above-mentioned problem is solved by providing a signal processing section that spectrally spectra the light collected by the optical system and processing the signal, and detecting the element to be measured in the sample.

[0006]

[Operation] The embodiment of the present invention operates as follows. That is,
A sample introduced together with plasma gas from the inlet is supplied through the inner tube, and is dissociated within the microwave-induced plasma to emit light. This emission spectrum is taken out in the axial direction from the outer tube, guided into the optical system through an optical window, and focused.Then, it passes through a slit and is separated by a spectrometer.After that, it is processed as a signal and the elements in the sample are measured. Is displayed. Therefore, the element to be measured in the sample can be accurately measured without being affected by dirt on the outer wall of the inner tube.

On the other hand, after measurement or during maintenance work,
The discharge tube is pulled out from the cavity by sliding the slider, and then rotated 90 degrees counterclockwise about the fulcrum. By doing this, the inner tube can be seen from above. Furthermore, even after replacing the outer tube, the center of the torch can be very easily aligned with the center of the outer tube.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. FIG. 1 is a cross-sectional view of the main part of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the overall structure of the embodiment of the present invention. 1 and 2, 1a is an outer tube of the discharge tube 1 made of, for example, a quartz tube, 1b is a torch made of, for example, a quartz tube or a stainless steel inner tube and inserted into the outer tube 1b, 2a to 2c are joints, 3a,
3b is a nut, 4 is a sample introduction port, and 5 is a cylindrical tube that induces microwave-induced plasma 6 in the outer tube 1 by making the cavity resonate with microwaves of, for example, 2.45 GHz supplied from the microwave generator 10. The cavity, 7 is an optical window, and 8 is a condensing system, which has a concave mirror 81 and a reflecting mirror 82.

Further, 9 is a signal processing section, and 11 is a slider.
, 12 is a base, 13 is a fulcrum, and 14 is an adjustment screw. On the other hand, in FIG. 1, the outer diameter A of the torch 1b is made to match the inner diameter of the outer tube 1a, and the torch 1 is placed inside the outer tube 1a.
By simply inserting the outer tube 1a, the center of the outer tube 1a and the center of the torch 1b are aligned. Also, torch 1b
The inner diameter B of the tip of the torch 1 is narrowed so that the particles are drawn out from the center of the torch 1, and the inner radius E of the non-tip part of the torch 1 is narrowed so that the particles are extracted from the center of the torch 1. It has a wide shape so as not to apply heavy loads.

Further, the tip of the torch 1b having an inner diameter B has a certain length C so that the fine particles are ejected parallel to the center of the torch 1b. Further, the structure has a taper D between the tip portion of the torch 1b having an inner diameter B and the non-tip portion of the torch 1b having an inner diameter E.

In the embodiment of the present invention having such a configuration, the outer diameter of the torch 1b is made to match the inner diameter A of the outer tube 1a, and the torch 1b is made to be different from the outer tube 1a. The center of the torch 1b and the center of the outer tube 1a can be aligned by simply inserting the outer tube 1a.

[0012] Also, a sample (for example, a solid particle) introduced together with a plasma gas (for example, Ar or He) through the inlet 4 may be
Tickle) is supplied through the inner tube 1b and is dissociated in the microwave induced plasma 6 to emit light. This emission spectrum is taken out in the axial direction from the outer tube 1a, guided into the optical system 8 through the optical window 7, and condensed, then passed through the slit 83, separated by the signal processing section 9, and then subjected to signal processing. The elements in the sample are measured and displayed. For this reason, the outer tube 1a
The element to be measured in the sample can be measured accurately without being affected by dirt on the outer wall of the sample.

On the other hand, after measurement or during maintenance work,
The torch 1b is replaced as follows. That is, the discharge tube 1 is pulled out from the cavity 5 by sliding the slider 11 in the direction of the arrow in FIG. By doing this, you can
1b can now be seen from above in FIG. Further, by inserting the torch 1b into the outer tube 1a after replacing the outer tube 1a, the center of the torch 1b can be aligned with the center of the outer tube 1a.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways. For example, a pretreatment device may be added to the inlet 4 to handle any of liquid, gas, and solid samples. It may also be made measurable. Alternatively, the light from the condensing system may be guided to a plurality of signal processing units using optical fibers to simultaneously measure a plurality of elements contained in the sample. In this case, since the condensing system can efficiently extract light as described above, the decrease in sensitivity inside the optical fiber can be sufficiently compensated for and high-sensitivity measurement can be performed. Furthermore, a capillary may be connected to the inlet 4 to sample and analyze only the sample gas at the extreme (extremely limited portion).

[0015]

Effects of the Invention According to the embodiments of the present invention as described in detail above, the following effects (1) to (3) can be obtained, and as a result, plasma is generated in the center of the discharge tube, and fine particles are generated in the center of the plasma. A plasma emission spectroscopic detector equipped with a torch that can inject ions has been realized. ■The structure of the torch has been modified so that particles can be injected into the center of the plasma, which improves the dissociation efficiency of particles and the luminous efficiency. ■The outer diameter of the torch is made to match the inner diameter of the outer tube, so just by inserting the torch into the outer tube, the center of the torch and the center of the outer tube will align. . ■Since the throttle is only provided at the tip of the torch, the pressure loss caused by the presence or absence of the throttle is slight, and the effect on the particle introduction device in the previous stage can be ignored.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main part of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the overall configuration of an embodiment of the present invention. 1
Discharge tube 1a Outer tube 1b Torch 5 Cavity 7 Optical window 8 Condensing system 81 Concave mirror 82 Reflector 83 Slit 9 Signal processing unit 11 Slider 12 Base 13 Fulcrum

Claims (1)

[Claims] 1. An emission spectrometer detector installed as a detector in an emission spectrometer that analyzes elements in a sample using microwave-induced plasma, which includes a discharge tube and a distal end of the discharge tube inserted into the discharge tube. A torch provided with an aperture, a cavity that generates microwave-induced plasma in the discharge tube by causing microwave resonance, and light emitted from the microwave-induced plasma is taken out in the axial direction of the discharge tube. A plasma emission spectroscopic detector that detects an element to be measured in the sample, comprising an optical system that collects light using the optical system, and a signal processing unit that spectrally spectrally and performs signal processing on the light collected by the optical system.