JPH1140100A - High-frequency induction coupled plasma spectrograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily fit a plasma torch in place by providing a positioning means which positions in relation to a torch holding member which fixes the plasma torch. SOLUTION: A positioning protrusion 4 of the device is made of a tubular member, and is fitted from the outside to a prescribed position of a plasma torch 1 of, for example, a triple tubular structure, then is integrated with the torch. At the time of positioning, the positioning protrusion 4 is constituted in such a way that an end face 4a of it which faces the tip side of the plasma torch 1 closely contacts with an end face 2a which faces the rear end side of the plasma torch 1 of a torch holding member 2. The position of the plasma torch 1 in relation to the torch holding member 2 can be easily positioned only by fixing the plasma torch 1 by the torch holding member 2 while the end face 4a of this positioning protrusion 4 is contacted with the end face 2a of the torch holding member 2, therefore the plasma torch 1 can be fitted in place easily and precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high frequency inductively coupled plasma / mass spectrometer (ICP-MS) or a high frequency inductively coupled plasma / emission spectrometer (ICP-AES).
And the like, and more particularly, to a plasma torch of an ICP device.

[0002]

2. Description of the Related Art Conventionally, when a plasma torch is mounted on an ICP device, the relative position of the plasma torch inserted into the induction coil with respect to the induction coil is visually confirmed and the plasma torch is fixed to a torch holding member. I am trying to do it.

In general, in an ICP apparatus, a shield plate grounded between the plasma and the induction coil is mounted between the plasma and the induction coil to electrostatically shield the space between the plasma and the induction coil. Conventionally, it is considered that an electric field is generated between the shield plate and a metal member such as a torch pressing member, and the electric field ignites the plasma.

[0004]

However, in the method of fixing the plasma torch to the torch holding member while visually confirming the relative position of the plasma torch as in the above-mentioned conventional method, the plasma torch is shifted from the optimum position depending on the viewing angle. There was a problem that it shifted. There is also a problem that the position of the plasma torch may be shifted after the positioning of the plasma torch is completed and before it is fixed by the torch pressing member.

In the conventional ICP apparatus, when the length of the shield plate is changed, particularly when the length of the shield plate is increased, the electric field for plasma ignition is weakened or not generated at all, and the plasma is ignited. There was a problem that it was difficult or did not ignite.

The present invention has been made to solve the above problems, and has as its object to provide an ICP apparatus in which a plasma torch can be easily attached to a predetermined position. Another object of the present invention is to provide an ICP device that can always ignite plasma regardless of the length of the shield plate.

[0007]

An IC according to claim 1
The P device is characterized in that positioning means for determining a relative position with respect to a torch holding member for fixing a plasma torch is provided in the plasma torch.
Thereby, the relative position of the plasma torch with respect to the torch holding member can be easily determined.

According to a second aspect of the present invention, there is provided an ICP apparatus according to the first aspect, wherein the positioning means is a positioning projection provided so as to contact one end surface of the torch pressing member. Is what you do. Thus, the relative position of the plasma torch with respect to the torch holding member can be easily determined only by bringing the positioning projection of the plasma torch into contact with one end surface of the torch holding member.

According to a third aspect of the present invention, there is provided an ICP apparatus, wherein an auxiliary electrode grounded at a high frequency is provided near the plasma torch and at a predetermined distance from the shield plate. Thus, when the plasma is ignited, an electric field for plasma ignition is generated between the auxiliary electrode and the shield plate.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS.

(First Embodiment) FIG. 1 shows an example of a portion around a plasma torch of an ICP apparatus according to the present invention. In the figure, 1 is a plasma torch for generating a high frequency inductively coupled plasma, 2 is a torch holding member for detachably mounting the plasma torch 1, 3 is a high frequency induction coil, 4 is a positioning for positioning the mounting position of the plasma torch 1. Convex part, 6 is a nozzle called a sampling cone, 7 is a skimmer cone, 8 is a vacuum pump, 9 is a fore chamber vacuum-sucked by a vacuum pump, 10
Is a center chamber for storing an ion lens (not shown), 11 is a valve for partitioning the inside of the center chamber 10,
Reference numeral 12 denotes an oil diffusion pump that sucks a vacuum in the center chamber. Although not shown, a rear chamber and an oil diffusion pump for vacuum suction of the rear chamber are provided behind the center chamber 10.

The positioning projection 4 is made of, for example, a tubular member as shown in FIG. 2, and is fitted to a predetermined position of, for example, a plasma torch 1 having a triple tube structure and is integrated with the torch 1. When the plasma torch 1 is positioned at a predetermined position, the positioning convex portion 4 has an end surface 4 facing the front end side (the right side in FIG. 2) of the plasma torch 1.
a comes into contact with an end surface 2a of the torch pressing member 2 facing the rear end side (left side in FIG. 2) of the plasma torch 1.

Therefore, when attaching the plasma torch 1, the end face 4 a on the front end side of the positioning projection 4 is brought into contact with the end face 2 a on the rear end side of the torch holding member 2, and in this state, the plasma is Fix the torch 1.

According to the first embodiment, the plasma torch 1 is fixed only by the torch holding member 2 in a state where the end surface 4a of the positioning projection 4 is in contact with the end surface 2a of the torch holding member 2, and the torch can be obtained. Since the relative position of the plasma torch 1 with respect to the pressing member 2 can be easily positioned, the plasma torch 1 can be easily and accurately attached to a predetermined position.

The positioning means is not limited to the above-described positioning projection 4, and a positioning mark 5 may be written at a predetermined position on the outer peripheral surface of the plasma torch 1, for example, as shown in FIG. In the example of FIG. 3, the positioning mark 5 is formed of a linear mark that exactly matches the position of the end face 2 a on the rear end side of the torch pressing member 2 when the plasma torch 1 is positioned at a predetermined position. I have.

The present invention is not limited to the first embodiment, and it goes without saying that various changes can be made. For example, the positioning protrusion 4 is not limited to a tubular shape, but may be a plasma torch 1.
The protrusion may have any shape as long as it can protrude from the outer peripheral surface of the torch holding member 2 and come into contact with the end surface 2a.

(Second Embodiment) FIG. 4 shows another example of a part around the plasma torch of the ICP apparatus according to the present invention. In the figure, 21 is a plasma torch, 22 is a torch pressing member, 23 is a high frequency induction coil, 24 is a shield plate, and 25 is an auxiliary electrode. In this example, for example, the rear (left side in FIG. 4) end of the shield plate 24 is inserted into the torch holding member 22.

The auxiliary electrode 25 is made of a conductor such as a ring-shaped metal, and is electrically insulated from the plasma torch 21 and the torch pressing member 22, and is grounded at a high frequency. The auxiliary electrode 25 is interposed between the plasma torch 21 and the torch pressing member 22 and near the end of the torch pressing member 22 on the side where the shield plate 24 is not inserted (the left side in FIG. 4). ing.

Specifically, the auxiliary electrode 25 and the shield plate 2
Suitably, the distance d between them is 4 to 25 mm. The reason is that when the distance between the auxiliary electrode 25 and the shield plate 24 is less than 10 mm, the probability that the ions accelerated by the electric field hit the surrounding gas molecules decreases, and when the distance exceeds 25 mm, This is because the generated electric field becomes weak and it is impossible to secure an electric field of a magnitude necessary for ignition.

According to the second embodiment, the auxiliary electrode 25
Is provided, an electric field for plasma ignition is generated between the auxiliary electrode 25 and the shield plate 24 at the time of plasma ignition, so that plasma ignition is always performed regardless of the length of the shield plate 24. It becomes possible.

The present invention is not limited to the above-described second embodiment, and it goes without saying that various changes can be made. That is, the auxiliary electrode 25 is not limited to an annular shape,
The shape is not limited as long as it is electrically insulated from the torch holding member 22 and is grounded at a high frequency to generate an electric field for plasma ignition. For example, an arc shape that is about half the circumference of the plasma torch 21 may be used.

[0022]

According to the first aspect of the invention, since the plasma torch is provided with positioning means for determining a relative position with respect to the torch holding member for fixing the plasma torch, the relative position of the plasma torch with respect to the torch holding member is provided. Since the position can be easily determined, the plasma torch can be easily attached to a predetermined position.

According to the second aspect of the present invention, since the positioning means is constituted by the positioning protrusion provided so as to abut on one end surface of the torch pressing member, the positioning protrusion of the plasma torch is connected to the torch. The relative position of the plasma torch with respect to the torch holding member can be easily determined only by contacting one end surface of the holding member, so that the plasma torch can be easily attached to a predetermined position.

According to the third aspect of the present invention, since the auxiliary electrode grounded at a high frequency is provided near the plasma torch and at a position separated from the shield plate by a predetermined distance, when the plasma is ignited, Since an electric field for plasma ignition is generated between the auxiliary electrode and the shield plate, the plasma can always be ignited regardless of the length of the shield plate.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a main part of a first embodiment of an ICP device according to the present invention.

FIG. 2 is a sectional view showing an example of a plasma torch of the ICP device.

FIG. 3 is a cross-sectional view showing another example of the plasma torch of the ICP device according to the present invention.

FIG. 4 is a schematic sectional view showing a main part of a second embodiment of the ICP device according to the present invention.

[Explanation of symbols]

 1, 21 Plasma torch 2, 22 Torch holding member 2a End face of torch holding member 3, 23 High frequency induction coil 4 Positioning convex part (positioning means) 4a End surface of positioning convex part 5 Positioning mark (positioning means) 6 Sampling cone 7 Skimmer cone Reference Signs List 8 vacuum pump 9 fore chamber 10 center chamber 11 valve 12 oil diffusion pump 24 shield plate 25 auxiliary electrode

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshifumi Matsuzaki 1-15-5 Nakamachi, Musashino-shi, Tokyo Mitaka Takagi Building Yokogawa Analytical Systems Co., Ltd.

Claims (3)

[Claims] 1. A high-frequency inductively coupled plasma analyzer that supplies high-frequency power to an induction coil disposed around a plasma torch to generate plasma and analyzes a sample using the plasma. A high frequency inductively coupled plasma analyzer, wherein positioning means for determining a relative position with respect to a torch holding member to be fixed is provided in the plasma torch. 2. The high-frequency inductively coupled plasma analyzer according to claim 1, wherein the positioning means is a positioning projection provided so as to contact one end surface of the torch holding member. 3. A high-frequency inductively coupled plasma analyzer that supplies high-frequency power to an induction coil disposed around a plasma torch via a shield plate to generate plasma, and analyzes a sample using the plasma. A high-frequency inductively-coupled plasma analyzer, wherein an auxiliary electrode grounded in a high-frequency manner is provided near the plasma torch and at a predetermined distance from the shield plate.