JPH08304286A - Icp emission spectroscopic analyzer - Google Patents

Abstract

PURPOSE: To realize a high sensitivity, high response measurement while suppressing the consumption rate of sample by inclining a plasma torch such that the induction coil side thereof is located obliquely above. CONSTITUTION: Mist having large diameter generated from a nebulizer strikes against the wall face of a spray chamber 1 and drops and then collected in a drain receiver 10 through a discharge port 8 and a discharge pipe 9. Mist smaller than a predetermined diameter is introduced into a plasma torch 7 through a mist outlet 5 and a discharge pipe 6. Since the torch 7 is installed while inclining, weaker gravity acts on the mist as compared with vertical installation and a larger volume of mist is introduced to the torch 7. Consequently, the mist can be introduced efficiently to the torch 7 and the measurement can be carried out with same order of sensitivity as a system where the torch 7 is installed horizontally. Furthermore, since the light emitted from a plasma 16 is measured on the extension of the axis of torch 7 inclining at an angle of 45 deg., for example, the background is lowered resulting in a high sensitivity high response measurement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductively coupled high frequency plasma.
asma, ICP) and an emission spectroscopy analyzer (hereinafter referred to as ICP emission spectroscopy analyzer) using discharge.

[0002]

2. Description of the Related Art In a conventional ICP emission spectroscopic analyzer, for example, as shown in FIGS. 5A and 5B, a nebulizer gas for spraying a sample solution (analysis sample) 32 in a sample container 31. A spray chamber (spraying chamber) 34 having a nebulizer (atomizer) 33 for sucking up and spraying by (usually argon gas is used) is held horizontally, and a plasma torch 35 is provided vertically. As shown in FIG. 6, there is a type in which the spray chamber 34 is tilted so that the nebulizer 33 side is upward and the plasma torch 35 is held horizontally.
In these figures, 36 is a drain part and Ar is an argon gas.

[0003]

The structure shown in FIG. 5 is generally adopted in ICP-AES (Inductively Coupled High Frequency Plasma Emission Spectrometer).
The sample in the mist state must be supplied to the vertically arranged plasma torch 35 against the gravity, and the sample introduction efficiency is low. The light emitted from the plasma torch 35 is observed from the side of the plasma torch 35 as shown by an arrow A in the figure. However, there is a drawback that the S / N becomes worse.

Further, the structure shown in FIG.
It is generally used in MS (inductively coupled high frequency plasma mass spectrometer) and the like, but since the plasma torch 35 is held horizontally, the plasma torch 3
There is a drawback that the amount of the sample introduced into sample 5 becomes too large and the plasma becomes unstable. Further, if the amount of the sample introduced into the horizontal plasma torch 35 is reduced in order to stabilize the plasma, there is a problem that the time required for the sample to reach the plasma torch 35 becomes long and the responsiveness deteriorates.

The present invention has been made in consideration of the above matters, and provides an ICP emission spectroscopic analyzer capable of performing measurement with high sensitivity and high responsiveness while suppressing the consumption rate of a sample to a low level. It is an object.

[0006]

In order to achieve the above object, the present invention is an ICP emission spectroscopic analyzer in which a sample for analysis is introduced into a plasma torch via a spray chamber, and the plasma torch is guided by the plasma torch. The coil side is inclined so that it is located diagonally above.

[0007]

In the ICP emission spectroscopic analyzer having the above structure, since the plasma torch is tilted so that the induction coil side is located obliquely upward, the resistance due to gravity is reduced as compared with the case where the plasma torch is installed vertically. The introduction efficiency is improved, and the same level of sensitivity can be obtained even with a small number of samples. In addition, when the photometry is performed from the extension of the inclined plasma torch, the background is lowered, and more sensitive measurement can be performed with good responsiveness.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. 1 and 2 are a schematic front view and a side view schematically showing a main part of an ICP emission spectroscopic analysis apparatus according to a first embodiment of the present invention. In these drawings, 1 is a spray chamber, The main body is held horizontally. Then, on one end side of the spray chamber 1, for example, a coaxial nebulizer 2 in which an argon gas nozzle 2b is concentrically arranged outside the sample solution nozzle 2a is integrally provided with the spray chamber 1. Reference numeral 3 is a sample solution (analysis sample) L introducing pipe connected to the sample solution nozzle 2a, and 4 is an argon gas (Ar) introducing pipe connected to the argon gas nozzle 2b.

A mist outlet 5 is provided at an appropriate position on the other end side of the spray chamber 1, and the mist outlet 5 is
A plasma torch 7 (described later) is connected via a connecting pipe 6. Further, a drain outlet 8 is opened between the nebulizer 4 and the mist outlet 5 of the spray chamber 1,
The discharge port 8 is connected to a drain storage tank 10 via a discharge pipe 9.

The plasma torch 7 is formed of a triple tube of quartz and is connected to the connecting tube 6 to flow a sample mist S and a carrier gas (eg, argon gas) and a sample gas flow path 11, an auxiliary gas (eg, Auxiliary gas channel 12 through which argon gas) flows and cooling gas (for example, argon gas)
And a cooling gas flow path 13 through which the gas flows are arranged concentrically from the inside to the outside in this order, and an induction coil 14 is provided around the outer periphery in the vicinity of the tip.

The plasma torch 7 is appropriately tilted so that its induction coil 14 side is located obliquely upward, and the angle θ (tilt angle) in FIG. 1 is 4 degrees.
It is set to be 5 °. Reference numeral 15 is a photometric unit for observing the light emitted by the plasma 16 generated in the tilted plasma torch 7, which is arranged at an appropriate distance on an extension of the axis CL of the tilted plasma torch 7. Reference numeral 17 denotes an incident optical system, which is schematically shown.

The operation of the ICP emission spectroscopic analyzer constructed as described above will be explained. The fog generated by the nebulizer 2 has a large diameter and is spray chamber 1.
It falls on the wall surface and is stored in the drain storage tank 10 through the discharge port 8 and the discharge pipe 9. Then, a small mist having a predetermined diameter or less is introduced into the plasma torch 7 through the mist outlet 6 and the connecting pipe 6. In this case, since the plasma torch 7 is provided so as to be inclined, the gravity acting on the fog is weaker than in the case where the plasma torch 7 is installed in the vertical direction. Therefore, the plasma torch 7 contains more sample fog S. be introduced.

Incidentally, when the same signal intensity is obtained, the sample introduction amount is as follows: when the plasma torch is vertical as shown in FIG. 5, the carrier gas flow rate is 0.35 l / min.
The sample introduction rate was 2 ml / min, and when the plasma torch was horizontal as shown in FIG. 6, the carrier gas flow rate was 0.
At 27 l / min, the sample introduction amount is 1 ml / min, and when the plasma torch 7 is obliquely arranged as in this embodiment, the value falls between the above numerical values. Then, the same degree of sensitivity can be obtained by only introducing the sample to this extent.

Even if the number of samples is reduced in this way,
Since the sample mist S can be efficiently introduced into the plasma torch 7, the measurement can be performed with the same sensitivity as that of a so-called horizontal type in which the plasma torch shown in FIG. 4 is installed horizontally. Then, the light emitted by the plasma 16 is changed to 4
Since the observation is performed on the extension of the axis of the plasma torch 7 tilted at 5 °, the background is lowered and the measurement can be performed with higher sensitivity.

FIG. 3 and FIG. 4 show a second embodiment of the present invention. In this second embodiment, a plasma torch 7 is used.
The spray chamber 1 provided below is also inclined. That is, in the second embodiment, the spray chamber 1 is tilted so that the nebulizer 2 side faces upward. In these figures, 18 is a trumpet-shaped guide member for selecting fog.

The operation and effect of the second embodiment are the same as those of the first embodiment, and detailed description thereof will be omitted.

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways. For example, the spray chamber 1 may be a double type or a cyclone type. And the nebulizer 2 may be a cross flow type.

The tilt angle θ of the plasma torch 7 may be changed. This is because the size of the fog generated by the viscosity and surface tension of the sample liquid L is different,
This is because the gravity acting on this changes and the flow rate of the sample also changes, so that the optimum condition for the sample liquid can be obtained by appropriately setting the inclination angle θ. Also, for the same reason, the inclination angle of the spray chamber 1 in the second embodiment may be changed.

The present invention also relates to ICP-AES and IC.
It can also be applied to P-MS and the like.

[0020]

As described above, according to the present invention, it is possible to perform measurement with high sensitivity and good responsiveness while suppressing the sample consumption rate to a low level. When the light emitted by the plasma is observed on the extension of the axis of the tilted plasma torch, the background is lowered and the measurement can be performed with higher sensitivity.

[Brief description of drawings]

FIG. 1 is a front view schematically showing a main part of an ICP emission spectroscopy analyzer according to a first embodiment of the present invention.

FIG. 2 is a side view schematically showing a main part of the ICP emission spectroscopy analyzer.

FIG. 3 is a front view schematically showing a main part of an ICP emission spectroscopy analyzer according to a second embodiment of the present invention.

FIG. 4 is a side view schematically showing a main part of the ICP emission spectroscopy analyzer.

5A and 5B are schematic views showing a main part of a conventional ICP emission spectroscopic analyzer in which a plasma torch is vertical, in which FIG. 5A is a side view and FIG. 5B is a front view.

FIG. 6 is a side view schematically showing a main part of a conventional ICP emission spectroscopic analyzer in which a plasma torch is horizontal.

[Explanation of symbols]

1 ... Spray chamber, 7 ... Plasma torch, 14 ... Induction coil, L ... Analytical sample.

Claims (1)

[Claims] 1. An ICP emission spectroscopic analyzer in which an analysis sample is introduced into a plasma torch through a spray chamber, wherein the plasma torch is inclined so that its induction coil side is located obliquely upward. ICP emission spectroscopy analyzer.