JPS6398948A - High frequency inductive coupling plasma/mass spectrometer - Google Patents

Abstract

PURPOSE:To make a shield tight to enable plasma to be maintained normally, by generating high frequency inductive coupling plasma followed by sliding a shield plate in the direction of a plasma torch to put a shield into a gap to be formed by an arc-preventive tube and the plasma torch. CONSTITUTION:An arc-preventive tube 7 is mounted on a coil 2 for being fixed in advance, then a high frequency current is made to flow through the coil 2 to form a high frequency magnetic field around the coil 2. When electrons or ions are planted in argon gas inside a plasma torch 1 in the vicinity of said high frequency magnetic field, plasma 4 is instantly generated by the action of the high frequency magnetic field. In this state, a shield plate 9 is made to slide in the direction of the plasma torch 1 and the shield 8 is inserted into a gap to be formed by the arc-preventive tube 7 and the plasma torch 1 for mounting the shield 8 on the outside of the plasma torch 1. Accordingly, the shield 8 is tight and able to normally maintain plasma 4.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a high frequency inductively coupled plasma/mass spectrometer (Industrial Application Field) which combines a high frequency inductively coupled plasma and a mass spectrometer.
ductively coupled plasma・
HassSpcctometer, hereinafter rlcP -
(abbreviated as MSJ).

<Prior art>ICr'-MS uses high-frequency inductively coupled plasma to excite a sample, and the generated ions are guided to a mass spectrometer through an interface consisting of a nozzle or skimmer, and ions of a specific mass are extracted. It is configured to analyze the element to be measured in the sample by electrically detecting and precisely measuring the amount of the ions. FIG. 3 is an explanatory diagram of the main part configuration of a conventional example of IcP-MS as shown in 2. In the figure, 1 indicates, for example, the outermost chamber 1a, the outer chamber 1b, and the inner chamber I.
2 is a high frequency: S conductive coil wound around the torch 1; 3 is a high frequency power source that supplies a high frequency current to the coil 2 via a capacitor Ct and Cx; 4 is a high frequency Inductively coupled plasma, 5 is a nozzle, and 6 is a skimmer. In this figure, when the high frequency current is passed through the coil 2, a high frequency magnetic field is formed around the coil 2. When electrons or ions are planted in the argon gas in the plasma torch 1 near this high frequency magnetic field, plasma 4 is instantaneously generated by the action of the high frequency magnetic field, and the plasma has a constant high frequency potential.

On the other hand, the plasma 4 and the high frequency induction coil 2 are capacitively coupled, and the plasma 4 has a high frequency potential. On the other hand, since the nozzle 5 and the skimmer 6 are normally connected to the ground and have a ground potential, discharge occurs between the tips of the nozzle 5 and the skimmer 6 and the plasma 4. In addition, the ions extracted from the plasma 4 into the skimmer 6 lose their ion characteristics obtained in the plastic/clump 4 due to the shadow of such discharge, which ultimately impairs the analysis accuracy of ICP-MS. This results in a significant decrease in In order to prevent such a decrease in analysis accuracy, a shield has been installed between the plasma 4 and the coil 2.

<Problems to be Solved by the Invention> However, in the conventional example described above, there was a major drawback in that the more severe the shield placed between the plasma 4 and the coil 2, the less the plasma 4 would be generated. .

The present invention has been devised to overcome the drawbacks of the conventional example, and its purpose is to eliminate the ff1ff! shield disposed between the plasma 4 and the coil 2. The object of the present invention is to provide an ICP-MS that can maintain the plasma 4 normally.

Means for Solving the Problems> The #+f feature of the present invention that solves the above problems is that I
In cP-MS, after generating high-frequency inductively coupled plasma, the shield plate is slid in the direction of the plasma torch, and the shield is tilted into the gap formed between the arc prevention tube and the plasma torch. This is due to the fact that it has been configured to

<Example> The present invention will be described below with reference to the drawings. 1st
The figure is an exploded configuration perspective view of the main parts of the embodiment of the present invention,
In the figure, the same symbols as in FIG. 3 are used with the same meaning, and repeated explanation will be omitted here.

Further, 7 is a quartz tube, for example, and is an arc prevention tube that prevents arc discharge, 8 is a shield inserted outside the plasma torch 1, and 9 is a shield 8 whose bottom 8' is fixed with a screw or the like. This is a shield plate that has been treated with a high-temperature finish. In FIG. 1, an arc prevention tube 7 is installed and fixed to the coil 2 in advance.

Thereafter, a high frequency current is passed through the coil 2 to form a high frequency magnetic field around the coil. When electrons or ions are planted in the argon gas in the plasma torch l near this high frequency magnetic field, plasma 4 is instantaneously generated by the action of the high frequency magnetic field. In this state, the shield plate 9 is slid in the direction of the plasma torch 1, and the shield 2 is inserted into the gap formed between the arc prevention tube 7 (ie, the coil 2) and the plasma torch 1. By doing so, the shield 2 is inserted outside the plasma torch l. Also,
Although the shield 2 is strong, the plasma 4 does not disappear. Therefore, Ic having the main part configuration as shown in FIG.
In P-MS, the shield 8 is strict and the plasma 4 can be maintained normally.

FIG. 2 is an explanatory diagram of the overall configuration of an embodiment of the present invention. In the figure, the same symbols as in FIGS. 1 and 3 are used with the same meanings, and redundant explanation will be omitted here.

In addition, loa is an argon gas supply source, IOb is a gas regulator, 11 is a tank for storing the sample, 12 is a nebulizer that unifies the sample to form an aerosol sample, 13 is a drive unit including a high-frequency power source 3, and 14 is a plasma torch. A housing for storing 1
5 is a vacuum pump that suctions the inside of the forechamber 16 to, for example, 1 torr and generates 1Jt, 17 is a vacuum pump that suctions and exhausts the inside of the center chamber 18 to, for example, IF' torr, and 19 is, for example, a four-m pole mass filter. 20 is a vacuum pump that suctions the inside of the rear chamber 21, 22 is a secondary electron multiplier (t!i tube), and 23 is an arithmetic processing unit (for example, a microcomputer). In the embodiment of the present invention having such a configuration, a gas supply source 10 is connected to the outermost chambers 1a and Ib of the plasma torch 1 via a gas regulator 10b.
Argon gas is supplied from a. In addition, the inner chamber 1c is supplied with argon gas (the gas regulator lO
aerosol sample (supplied via b)
(is carried in. On the other hand, high-frequency energy is supplied to the coil 2 by the high-frequency power supply 3 in the drive unit 13, and a high-frequency magnetic field (not shown) is formed around the coil. A plasma 4 is generated under the action of a magnetic field.The ions within this plasma 4 are drawn out through a nozzle 5 into a skimmer 6 and then into a mass spectrometer detector 19.
ions of a specific mass are detected by The detection signal is amplified by the secondary electron multiplier tube 22 and then sent to the arithmetic processing section 23, and the R final song is given the analysis of the element to be measured m in the sample, etc.6 <Effects of the invention> Questions in detail above According to the present invention, plasma 4
An ICP-H5 is realized in which the shield disposed between the coil 20 and the coil 20 is made strict and the plasma 4 can be maintained normally.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the configuration of the end portion of the embodiment of the present invention, FIG. 2 is an explanatory diagram of the overall configuration of the embodiment of the present invention, and FIG. 3 is an explanatory diagram of the main part configuration of the conventional example. 1... Plasma torch, 2... High-rise Xa conductive coil,
3... High frequency power supply, 4... High frequency inductively coupled plasma, 7... Arc prevention tube, 8... Shield, 9...
shield board. 'P, Figure 2 #i'' Figure 3

Claims (2)

[Claims] (1) High-frequency energy is supplied to a high-frequency induction coil to form a high-frequency magnetic field to generate high-frequency inductively coupled plasma, the plasma is used to excite the sample to generate ions, and the ions are subjected to mass analysis via an interface. In the analyzer for detecting and analyzing the elements to be measured in the sample, the analyzer includes: an arc prevention tube installed in the coil in advance to prevent arc discharge occurring between the interface tip and the plasma; The method includes a shield inserted outside a plasma torch that generates plasma, and a shield plate to which the bottom of the shield is fixed, and after generating the plasma, the shield plate is slid in the direction of the plasma torch. . A high frequency inductively coupled plasma/mass spectrometer, characterized in that the shield is inserted into a gap formed between the arc prevention tube and the plasma torch. (2) The high frequency inductively coupled plasma mass spectrometer according to claim (1), wherein the interface comprises a nozzle and a skimmer.