JP2522350Y2 - High frequency inductively coupled plasma analyzer - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a high frequency inductively coupled plasma emission spectrometer (hereinafter referred to as ICP-AES) and a high frequency inductively coupled plasma mass spectrometer (hereinafter referred to as ICP-MS). And particularly to a sample introduction device.

[Outline of the invention]

In the present invention, in the ICP-AES and the ICP-MS, a resistor that resists the flow of the solution in the tube is provided in a tube behind the spray chamber and having a function of preventing air from being mixed into the plasma. It is characterized in that the tube is miniaturized and the measurement is stabilized by inserting the tube.

[Conventional technology]

The prior art will be described with reference to FIG. In FIG. 2, 1 is a sample solution, 2 is a capillary tube, 3 is a nebulizer, and 4 is a carrier gas. When the carrier gas 2 flows, the sample solution 1 is sucked up through the capillary tube 2, and is ejected from the tip of the nebulizer 3 together with the carrier gas 4 as a mist. Here, the sample solution 1 uses an aqueous solution or an organic solvent, and sometimes uses an acid. As the nebulizer 3, a concentric nebulizer, a cross-flow nebulizer, or the like is used. Reference numeral 5 denotes a spray chamber, 6 denotes a torch tube, 7 denotes an auxiliary gas, 8 denotes a plasma gas, 9 denotes a work coil, 11 denotes a communication tube, and 12 denotes a drain tank. Most of the mist ejected from the tip of the nebulizer 3 collides with the inner wall of the spray chamber 5 due to gravity or inertia, flows to the bottom, and is accumulated in the drain tank 12 through the communication pipe 11. The remaining classified fog is transported to the torch tube 6. Spray chamber 5
For example, a Scott type is used. The mist transported to the torch tube 6 is transported to the work coil 9 together with the plasma gas 8 and the auxiliary gas 7. Plasma gas 8, auxiliary gas 7,
Argon gas is often used for the carrier gas 4. The work coil 9 is supplied by a high frequency power supply (not shown), for example.
Since a high-frequency current of 27.12 MHz is applied, the transported fog and gas are inductively coupled to form a plasma 10. ICP
-At AES, sample 10
Perform quantitative and qualitative analysis of trace elements in the material. ICP-M
In S, mass spectrometry of ions in the plasma 10 is performed and sample solution 1
Perform quantitative and qualitative analysis of trace elements in the material. Now, the communication pipe 11 is a bent pipe, and according to the Dictionary of Chemistry (Editorial Committee of the Dictionary of Chemical Dictionary), a pipe filled with liquid connects the bottom part with the bottom part around the top part, so that the liquid can flow freely. It is like that. That is, as shown in FIG. 2, the structure is such that the pipe descends once, then rises and then connects to the drain tank 12. The solution 13 remains in the communication pipe 11. If air is present in the spray chamber 5 or the torch tube 6, the plasma 10 becomes unstable and adversely affects the analysis accuracy. However, the communication pipe 11 of this apparatus causes the outside air to enter the spray chamber 5 by the solution 13. It works without doing.

[Problems to be solved by the invention]

Problems of the prior art will be described with reference to FIG. In FIG. 2, the pressure in the spray chamber 5 is higher than the atmospheric pressure. Therefore, the level of the solution 13 in the communication pipe 11 is
There is a height difference between the side and the drain tank 12 side. This height difference becomes particularly large when an organic solvent is used for the sample solution 1. Therefore, in order to prevent air from entering the spray chamber 5, the height difference of the communication pipe 11 becomes large, that is, 20 cm or more.

A second problem of the prior art will be described with reference to FIG.
From the spray chamber 5, the liquid falls into the solution 13 as droplets 14 in the communication pipe 11. The solution 13 vibrates due to the drop impact.
Due to this vibration, the pressure in the spray chamber 5 fluctuates and the plasma
The amount of fog supplied to 10 changes, adversely affecting analytical accuracy.

To reduce this adverse effect, the volume of the spray chamber 5 or the solution 13 to the solution 13 must be increased.

A third problem of the prior art will be described with reference to FIG. When the solution 13 flows from the communication pipe 11 to the drain tank 12, the surface tension of the solution causes the drain tank 12 of the solution 13 to flow.
The side face is pulled. The solution 13 fluctuates at the moment when the droplet 15 is separated from the surface of the solution 13. As a result, pressure fluctuations in the spray chamber 5 occur, which adversely affects the analysis accuracy. To reduce this adverse effect, the volume of the spray chamber 5 and the volume from the spray chamber 5 to the solution 13 must be increased. .

[Means for solving the problem]

The present invention has been made in order to solve the above-mentioned problems, and includes a resistor in the tube, which resists the flow of the solution in the tube. The material of the resistor is suitably glass, aluminum oxide such as vinyl chloride or alumina, or fluorine resin such as PTFE.

[Action]

By placing a resistor in the tube as in the present invention that resists the flow of the solution in the tube, the following effects occur, and as a result, the tube can be miniaturized and the measurement can be stabilized.

First, due to the presence of the resistor in the communication pipe, the level difference between the liquid spray chamber side and the drain tank side becomes smaller than in the prior art. This is because while the amount of solution supplied from the spray chamber to the communication tube is constant (1 to 3 milliliters per minute), the resistance of the flow of the solution in the normal tube is larger than in the conventional technique, This is because a steady state occurs when the level difference of the liquid level is smaller than that corresponding to the pressure difference between the spray chamber pressure and the atmospheric pressure.

Further, when the droplets fall from the spray chamber to the communication pipe, the droplets first collide with the resistor. Therefore, the vibration of the solution, which is a problem in the prior art, is eliminated. Therefore, pressure fluctuation in the spray chamber 5 is also eliminated.

Further, in the communication pipe, the resistance of the flow of the solution becomes larger than that of the prior art due to the resistor, so that the droplet 15 in FIG.
Fluctuation of the solution 13 at the moment away from the liquid surface does not affect the pressure of the spray chamber 5.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. In FIG. 1, a sample solution 1, a capillary tube 2, a nebulizer 3, a carrier gas 4, a spray chamber 5, a torch tube 6, an auxiliary gas 7, a plasma gas 8, a work coil 9, a plasma 10,
The communication pipe 11, the drain tank 12, and the solution 13 are equivalent to those of the related art. 16 is a resistor. Resistor 16 is a communicating pipe
This is for imparting an appropriate resistance to the flow of the solution 13 in the tube 11, and has a spherical, sandy, gravel-like granular, sponge-like or fibrous shape. Also, in order to provide an appropriate resistance to the flow of the solution 13 while miniaturizing the communication pipe 11, a resistor 16 is required.
When the particles are granular, the particle size is suitably 3 mm or less. Communication pipe 11
As shown in FIG. 1, the U-shaped portion 11b, which is located behind the spray chamber 5 and is connected downward from the lowermost end portion 5a of the spray chamber 5 and bent upward in a U-shape, is continuously inverted. It has an inverted U-shaped portion 11a bent downward in a U-shape, and is configured to discharge the discarded sample solution 1 from the spray chamber 5.
The amount 16a of the resistor 16 is preferably such that the resistor 16 is located at a position higher than the liquid level of the solution 13 on the spray chamber 5 side of the communication pipe 11. As a material of the resistor 16, glass or vinyl chloride may be inexpensive. When hydrofluoric acid is used for the sample solution 1, the resistor 16 is preferably made of a fluorine-based resin such as PTFE which is not deteriorated by hydrofluoric acid, aluminum oxide such as alumina, or a material mainly containing aluminum oxide.

FIG. 5 shows a second embodiment of the present invention. In FIG. 5, the sample solution 1, the capillary tube 2, the nebulizer 3,
Carrier gas 4, spray chamber 5, torch tube 6, auxiliary gas 7,
The plasma gas 8, the work coil 9, the plasma 10, and the drain tank 12 are equivalent to those of the prior art. 16 is a resistor, and 17 is a support. In this embodiment, the resistor is directly attached to the direct pipe 18 without the communication pipe. The resistor 16 is similar in material and shape to that described in the previous embodiment, and has a solution soaked therein to prevent outside air from entering the spray chamber. The support 17 supports the resistor 16 so as not to fall down, and has a hole through which the solution passes. If the resistor 16 does not fall down from itself due to its elasticity, for example, in the form of a sponge, the support 17 can be omitted. The support 17 can also be omitted when the resistor 16 is prevented from falling down by, for example, constricting the tube with a porous sintered body. In the second embodiment, the space required for the communication pipe 11 can be omitted, and the pipe from the spray chamber 5 to the drain tank 12 is simplified. In addition, since the fluctuation of the solution in the resistor hardly occurs, the pressure fluctuation in the spray chamber 5 at the moment when the liquid drops fall on the resistor 16 or when the liquid drops away from the resistor 16 toward the drain tank 12, that is, the measurement becomes unstable. Elimination of the cause.

[Effect of the invention]

According to the present invention, the level difference between the liquid level on the solution spray chamber side and the liquid level on the drain tank side is smaller than in the prior art, and the pipe can be miniaturized. Further, the pressure fluctuation in the spray chamber 5 becomes smaller than that in the related art, and the stability of measurement is improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the present invention, FIG. 2 is a diagram illustrating the prior art, FIGS. 3 and 4 are diagrams illustrating the problems of the prior art, and FIG. 5 is a second diagram of the present invention. It is a figure showing an example. DESCRIPTION OF SYMBOLS 1 ... Sample solution 2 ... Capillary tube 3 ... Nebulizer 4 ... Carrier gas 5 ... Spray chamber 6 ... Torch tube 7 ... Auxiliary gas 8 ... Plasma gas 9 ... Work coil 10 ... Plasma 11 ... … Communication pipe 12 …… Drain tank 13 …… Solution 14 …… Drop 15 …… Drop 16 …… Resistance 17 …… Support 18 …… Direct pipe

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-170840 (JP, A) JP-A-62-50644 (JP, A) JP-A-61-138147 (JP, A) 87655 (JP, U) Fully open 1986-616749 (JP, U) Fully open 1983-103356 (JP, U) Fully open 1987-616351 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] A nebulizer for atomizing a sample solution for identifying a trace element in the sample solution; a torch tube and a work coil for converting the fog into plasma; a high-frequency power supply for applying a high-frequency current to the work coil; A spray chamber that sends a certain particle size of the mist to the torch tube and liquefies and discards the mist of an unnecessary particle size, and a lower portion of the spray chamber from the lowermost end of the spray chamber after the spray chamber. A U-shaped portion that is connected and bent upward in a U-shape, and has an inverted U-shaped portion that is subsequently bent downward in an inverted U-shape, and discharges the discarded sample solution from the spray chamber. A communication pipe for injecting at least a part of the upwardly bent U-shaped portion of the communication pipe, a solution for preventing outside air from entering the spray chamber, and a solution bent above the communication pipe. At least part of the U-shaped part A high-frequency inductively coupled plasma analysis comprising a granular or sponge-shaped resistor for inserting a solution to a position higher than the liquid level on the atomizer side and providing resistance to a flow for discharging the discarded sample solution. apparatus.