JPS62184755A - High frequency induction-coupled plasma mass spectrometer - Google Patents

Abstract

PURPOSE:To reduce a speed of ions introduced into a mass spectrometer to maintain a high resolution of a high frequency induction coupled plasma mass spectrometer, by generating discharge on a bottom part of a plasma torch to lower ion energy in the plasma. CONSTITUTION:Compressive gas, whose flow rate is regulated by a flow-rate regulator 7, is supplied into the most outer chamber 1a and an outer chamber 1b of a plasma torch, and a sample fogged by a nebulizer 9 is carried into an inner chamber 1c by the flow rate-regulated compressive gas. Then, high frequency energy is supplied into an induction coil 4 from a high frequency power source 10, to form a high frequency magnetic field around the coil 4 so that the plasma 5 is generated by the action of the said magnetic field. A compressive gas-introduced part 3 is installed on the bottom part of the plasma torch, and therefore discharge is generated so that it rotates near the induced part 3, reducing the ion energy in the plasma 5. Thus, the ions in the plasma 5 are drawn out through a nozzle 11 into a skimmer 12 and thereafter detected by a pole 17.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a high frequency inductively coupled plasma/mass spectrometer that combines a high frequency inductively coupled plasma and a mass spectrometer.

<Prior art> A high-frequency inductively coupled plasma/mass spectrometer uses high-frequency inductively coupled plasma to excite a sample, and guides the generated ions to a mass spectrometer through an interface consisting of a nozzle and skimmer to collect ions with a specific mass. By electrically detecting only ions.

The analyzer is configured to analyze an element to be measured in a sample.

However, in the case of a conventional high-frequency inductively coupled plasma/mass spectrometer, the ions introduced from the high-frequency induced plasma into the mass spectrometer via the above interface have high energy and the rate of incidence into the mass spectrometer is high. ing. For this reason.

Ions that enter the mass spectrometer pass through the mass spectrometer as they are and reach the ion detection element before the mass spectrometer separates ions of a specific mass. Therefore,
This has the disadvantage that the resolution of the high-frequency inductively coupled plasma/mass spectrometer is reduced, and the mass spectrum created based on the detection signal of the ion detection element also has poor analysis accuracy.

In addition, in order to maintain high resolution of the high-frequency inductively coupled plasma mass spectrometer even when the energy of the ions introduced into the mass spectrometer is high, we have increased the total length of the poles of the mass spectrometer and applied high-frequency voltage. Attempts were also made to increase the frequency of

This also brought about new drawbacks, such as an increase in the size of the device and an increase in manufacturing costs.

<Problems to be Solved by the Invention> The present invention has been made in view of the drawbacks of the conventional examples, and its purpose is to provide a high frequency inductively coupled plasma/mass spectrometer with high resolution and excellent analysis accuracy. There is a particular thing.

〈Means for solving problems〉 The features of the present invention that solve the above-mentioned problems are as follows.

A high frequency inductively coupled plasma/mass spectrometer.

The purpose is to generate a discharge at the bottom of the plasma torch to lower the ion energy in the plasma mainly generated by the plasma torch.

<Example> Hereinafter, the present invention will be explained in detail with reference to the drawings. 1st
Figure 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention, and in Figure 1, l
a, 11)+ and IC are respectively the outermost chamber, outer chamber, and inner chamber of a plasma torch made of, for example, a quartz tube, 2a
+ 2bl and 2C are first to third inlets for introducing compressed gas, such as argon gas, into the outermost chamber lap's, the outer chamber lb, and the inner chamber IC, respectively.

Reference numeral 3 denotes a compressed gas introduction part, which has gas introduction passages 2a' and 2b' communicating with the first and second introduction ports 2a+2b, and is made of a material suitable for generating electric discharge, such as a metal material or a semiconductor material; is a high frequency coil, and 5 is a plasma. For example, a tubular member 2d having a third inlet port 2C.
is connected to the inner chamber 1c so as to pass through the compressed gas introduction section 3. FIG. 2 is a configuration explanatory diagram showing the overall configuration of an embodiment of the present invention. In FIG. 2, the same symbols as in FIG. 1 are used with the same meanings, and redundant explanation will be omitted here. Also.

6 is a compressed gas (eg compressed argon gas) supply source.

7 is a flow rate regulator, 8 is a tank for storing the sample, 9 is a nebulizer for atomizing the sample, 10 is a high-frequency power supply that supplies high-frequency energy to the high-frequency coil 4, 11 is a nozzle, 12 is a skimmer, 13 is a forechan/ <-, 14 is a vacuum pump that suctions the inside of the forechamber 13 to, for example, 1 torr, 15 is a center chamber, 16 is a vacuum pump that suctions the inside of the center chamber 15 to, for example, 10-2 torr, and 17 is a mass spectrometer, for example. A pole element such as a quadrupole, 18 a rear chamber, 19 a vacuum pump that sucks the inside of the rear chamber 18 to, for example, 10-'torr, 20 a secondary electron multiplier, and 21 a microcombinator, for example. This is a signal processing section. still.

An ion lens may be disposed within the center chamber 15.

F like this! In an embodiment of the present invention consisting of four components,
In the outermost chamber 1a and outer chamber 1b of the plasma torch.

Compressed gas whose flow rate is regulated by a flow fU4 moderator 7 is supplied. Further, a sample atomized by the nebulizer 9 is carried into the inner chamber IC of the plasma torch by compressed gas whose flow rate is adjusted. In this state, high frequency energy is supplied from the high frequency power supply 10 to the induction coil 4, a high frequency magnetic field (not shown) is formed around the coil 4, and plasma 5 is generated by the action of the magnetic field. by the way,
As described in detail with reference to FIG. 1, the bottom of the plasma torch is provided with a compressed gas inlet 3 made of a material suitable for generating electric discharge. Therefore, a rotating electrical discharge is generated in the vicinity of the introduction section 3 (specifically, around the joint between the compressed gas introduction section 3 and the outer tube of the outer chamber 1b), and the electrical discharge generates plasma. The ion energy within 5 becomes lowered. The ions in the plasma 5 whose energy has been reduced in this way are extracted into the skimmer 12 through the nozzle 11 and then detected by the pole element 17.

The detection signal is amplified by a secondary electron multiplier tube 20 and then sent to a signal processing section 21 to ultimately provide an analysis value of the sample.

Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways. For example, the compressed gas introduction section may be replaced with the following configuration. The first is to insert a metal needle into the compressed gas introduction part to the outermost chamber (1a) of the glass plasma torch to facilitate the generation of electric discharge. A metal tube is connected to the piping that leads the compressed gas to the outermost chamber (la) and the outer chamber (lb) of the chamber to facilitate the generation of electric discharge. In addition, in Figures 1 and 2, the outermost chamber 1
The compressed gas introduction part 3 is configured to introduce compressed gas to the outermost chamber 1a or the outer chamber 1b.
The compressed gas introducing portion may be configured to guide the compressed gas only to one of them, and the other may be configured of a tubular member similar to the tubular member 2d.

<Effects of the Invention> According to the present invention as described in detail above, since the configuration is such that a discharge is generated at the bottom of the plasma torch to lower the ion energy in the plasma, the ions introduced into the mass spectrometer are The speed of 1. @An advantage is that the resolution of the frequency inductively coupled plasma/mass spectrometer remains high. Further, since the discharge occurs at the bottom of the plasma torch without contacting the sample, the sample is not affected by the discharge, and there is an advantage that the mass spectrum of the sample can be obtained normally.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the overall configuration of the embodiment of the present invention. 1a... outermost chamber, 1b outer chamber, lc... inner chamber, 2a
~2c...Gas inlet, 2d...Tubular member, compressed gas inlet for 3. 4...High frequency coil, 5...Plasma. Agent Patent Attorney Shinsuke Ozawa・-,゛・,1
″、−） ゛＼ノ

Claims (3)

[Claims] (1) A plasma torch with a triple tube structure having an outermost chamber, an outer chamber, and an inner chamber into which first to third compressed gases with controlled flow rates are guided, and a high-frequency induced plasma generated by the torch. An interface that guides the contained ions,
In a high-frequency inductively coupled plasma/mass spectrometer equipped with a mass spectrometer that detects ions of a specific mass among ions introduced through the interface, a discharge is generated at the bottom of the plasma torch, and the plasma A high-frequency inductively coupled plasma/mass spectrometer that is characterized by lowering the ion energy in the plasma generated by a torch. (2) The outermost chamber moss or the introduction part of the compressed gas into the outer chamber is made of a discharge-generating material that easily generates electric discharge, and the electric discharge is generated. High frequency inductively coupled plasma/mass spectrometer. (3) The high frequency inductively coupled plasma according to claim (2), wherein the discharge generating material is a metal or a semiconductor.
Mass spectrometer.