JPH03114131A - High frequency inductively coupled plasma mass spectrometer - Google Patents

Abstract

PURPOSE:To prevent injection of scattered light to a mass spectrometer by putting a scattered light preventing part consisting of a plurality of scattered light preventing plates which are surface-blackened in the surrounding of an ion passing route from a skimmer to a detector of a mass spectrometer. CONSTITUTION:When vaporized sample is led to high frequency inductively coupled plasma 7 to be ionized or to emit light, the ions in the plasma 7 are converged passing between ion lens 14a, 14b after passing a nozzle 8, a skimmer 9, and a drawing out electrode 9''. At that time, since scattered light in the route of ions is prevented from scattering by the scattered light preventing part 21, the scattered light does not return to the ion route. As a result, strength of detecting signal is not affected. The scattered light preventing part 21 consists of a plurality of scattered light preventing plates 22a-22n which are surface- blackened and put in the surrounding of the ion route from a skimmer 9 to a mass filter 16.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention supplies high-frequency energy to a high-frequency induction coil to form a high-frequency magnetic field to generate high-frequency inductively coupled plasma, and uses the plasma to excite a sample. The present invention relates to a high frequency inductively coupled plasma mass spectrometer that analyzes an element to be measured in the sample by generating ions through a nozzle and a skimmer, and guiding the ions to a mass spectrometer for detection through an interface consisting of a nozzle and a skimmer.

<Prior Art> FIG. 2 is an explanatory diagram of a general configuration of an analyzer using high-frequency inductively coupled plasma. In this figure, argon gas is supplied from an argon gas supply source 3 to an outer chamber 1b and an outermost chamber 1c of a plasma torch 1 via a gas regulator 2.
A solid sample in the sample introducing device 4 is vaporized by a laser beam irradiated from a laser light source 5 and then carried into the inner chamber 1a by argon gas as a carrier gas. If the sample is a liquid, the sample introducing device 4 and laser light source 5 shown in FIG. 2 are removed, and a nebulizer is installed to atomize the introduced liquid sample and supply it to the inner chamber 1a of the plasma torch 1. Also, the sample is more likely to be a liquid than a solid.

On the other hand, a high frequency current is passed through a high frequency induction coil 6 wound around the plasma torch 1 by a high frequency power source 10, and a high frequency magnetic field (not shown) is formed around the coil 6. When electrons or ions are planted in the argon gas in the vicinity of the high frequency magnetic field in this state, high frequency inductively coupled plasma 7 is instantaneously generated by the action of the high frequency magnetic field.

Further, the inside of the forechamber main body 11 sandwiched between the nozzle 8 and the skimmer 9 is pumped by a vacuum pump 12, for example.
For r r, is attracted to. Furthermore, ion lenses 14a and 14b are provided inside the center chamber 13, and the inside of the center chamber 13 is
The oil is sucked to, for example, 10-' Torr by the oil diffusion pump 15, and then passed through a mass filter (for example, a quadrupole mass filter).
The interior of the rear chamber 17 housing the oil pump 16 is suctioned to, for example, 10-'Torr by a second oil diffusion pump 18.

In this state, the sample vaporized as described above is introduced into the high-frequency inductively coupled plasma, and ionization and light emission are performed. The ions in the plasma 7 are transferred to the nozzle 8. skimmer 9
．． and the ion lens 1 via the extraction electrode 9-.
4a and 14b (or a doublet quadruple diameter lens), and then passed through a mass filter 16, guided to a secondary electron multiplier 19, and detected. This detection signal is sent to the signal processing section 20, where it is played and processed, thereby determining the analysis value of the element to be measured in the sample.

<Problems to be Solved by the Invention> However, in the above conventional example, the ions in the high frequency inductively coupled plasma 7 flow from the nozzle 8 to the gap 9 to the extraction electrode 9.
-→It passes through the ion lenses 14a and 14b and reaches the mass filter 16. Here, due to the filtering effect of the electric field in the mass filter 16, the electrons selectively pass through the mass filter 16 according to their mass, and then reach the secondary electron multiplier 19 and are detected. Although the light incident from the tip of the skimmer 8 can be effectively blocked by the doublet quadruple diameter lens 14b, the extraction electrode 9
There is a drawback that the light scattered by - and the ion lenses 14a and 14b cannot be blocked.

The present invention has been made in view of this situation, and its object is to provide a high frequency inductively coupled plasma mass spectrometer in which scattered light from the walls of the center chamber etc. does not enter the mass spectrometer detector. be.

Means for Solving the Problems> The present invention supplies high frequency energy to a high frequency induction coil to form a high frequency magnetic field to generate high frequency inductively coupled plasma, and uses the plasma to excite a sample to generate ions. , in a high frequency inductively coupled plasma mass spectrometer that analyzes the element to be measured in the sample by guiding the ions to a mass spectrometer through an interface consisting of a nozzle and a skimmer and detecting them. The above-mentioned problem is solved by disposing a light scattering prevention section consisting of a plurality of light scattering prevention plates around the ion path from the skimmer to the mass spectrometer detector.

Function> The present invention functions as follows. That is, when a vaporized sample is introduced into a high-frequency inductively coupled plasma to undergo ionization and light emission, the ions in the plasma pass through a nozzle, skimmer, and drawer Z'Fk, and then pass through an ion lens (or It is focused through a doublet (quadruple diameter lens). At this time, the light scattered on the path that the ions pass through is prevented from scattering by the light scattering prevention part (for example, it is absorbed and light scattering is prevented), and the scattered light returns to the path that the ions take. This is not the case, thus reducing the optical noise of the mass spectrometer.

<Example> Hereinafter, the present invention will be described in detail using the drawings. 1st
The figure is an explanatory diagram of the configuration of an embodiment of the present invention, and in the figure, the same symbols as in FIG. 3 are used with the same meaning, and repeated explanation here will be omitted. Moreover, FIG. 2 is a perspective view of the main part configuration of the embodiment of the present invention showing a light scattering prevention section. In FIGS. 1 and 2, reference numeral 21 indicates a plurality of light scattering prevention plates 22a to 22n with black surface treatment, and light scattering plates arranged around the ion path from the skimmer 9 to the mass filter 16. This is the prevention part.

In the embodiment of the present invention having such a configuration, when a vaporized sample is introduced into the high-frequency inductively coupled plasma 7 shown in FIG. 1 and ionization and light emission are performed, the plasma 7
The ions in the nozzle 8° skimmer 9. After passing through the extraction electrode 9- and the ion lenses 14a and 14b (or doublet quadrupole lens), it is focused. At this time, the light scattered on the path through which the ions pass is prevented from scattering by the light scattering prevention unit 21 (for example, is absorbed, thereby preventing light scattering), so that the scattered light is prevented from scattering on the path through which the ions pass. I'll never go back.

In this way, while light scattering is prevented, the extraction electrode 9-
The ions that have passed between the ion lenses 14a and 14b (or the tablet quadrupole lens) are then guided to the secondary electron multiplier 19 through the mass filter 16 and detected. This detection signal is sent to the signal processing section 20 where it is calculated and processed, thereby obtaining the analysis value of the element to be measured in the sample.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways, such as light scattering prevention plates 2fa to 2In.
The shape may be pyramidal.

<Effects of the Invention> According to the present invention as described in detail above, in a high-frequency inductively coupled plasma mass spectrometer, a light scattering prevention section consisting of a plurality of light scattering prevention plates with a black surface treatment is removed from the skimmer. A high-frequency inductively coupled plasma mass spectrometer is realized in which scattered light from the walls of the central chamber and the like disposed around the ion path leading to the mass spectrometer detector does not enter the mass spectrometer detector.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, FIG. 2 is a perspective view of the main part configuration of the embodiment of the invention, and FIG. 3 is an explanatory diagram of the configuration of a conventional example. 1... Plasma torch, 2... Flow rate control unit, 3... Argon gas supply source, 4...
...Sample cell, 6...High frequency induction coil, 7...High frequency inductively coupled plasma, 8...
・Nozzle, 9... Skimmer, 16...
Mass filter, 17... Rear chamber, 20
...Signal processing unit, 21...Light scattering prevention section, 21a~2in...Light scattering prevention board, patent attorney

Claims (1)

[Claims] High frequency energy is supplied to a high frequency induction coil to form a high frequency magnetic field to generate a high frequency inductively coupled plasma, the plasma is used to excite the sample to generate ions, and the ions are transferred through an interface consisting of a nozzle and a skimmer. In a high-frequency inductively coupled plasma mass spectrometer that analyzes the element to be measured in the sample by guiding it to a mass spectrometer and detecting it, a light scattering prevention section consisting of a plurality of light scattering prevention plates each having a black surface treatment is used. A high frequency inductively coupled plasma mass spectrometer, characterized in that: is arranged around the ion path from the skimmer to the mass spectrometer detector.