JP3764798B2 - Inductively coupled plasma mass and spectroscopic analyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inductively coupled plasma mass and spectroscopic analyzer, and more particularly to an organic solvent sample introduction device.
[0002]
[Prior art]
In the conventional inductively coupled plasma mass spectrometer, as shown in FIG. 2, a chamber 9 serving as a sample introduction unit is connected to a torch 4 for generating plasma 2. The chamber 9 is provided with a holder 12 with an atomizer 13 for atomizing the sample 18 at one end via an O-ring 11. The sample 18 stored in the sample container 17 is supplied to the nebulizer 13 through the sample supply pipe 16. Here, the nebulizer gas stored in the nebulizer gas supply unit 15 is supplied to the nebulizer 13 via the nebulizer gas supply pipe 14. After the sample 18 is atomized by the nebulizer 13, the atomized sample 18 is introduced into the torch 4 through the chamber 9. At the bottom of the chamber 9, the waste liquid holes 10 for discharging the waste liquid is provided.
[0003]
The torch 4 is composed of a coaxial triple tube, and the sample 18 introduced from the chamber 9 is introduced into the plasma 2 through the innermost tube 5 of the triple tube. The sample 18 is ionized in the plasma 2, passes through a hole in the sampling cone 1 constituting the inductively coupled plasma analyzer analysis unit, and then analyzed by a mass spectrometer (not shown). An intermediate pipe 8 a through which the auxiliary gas is passed through the auxiliary gas supply hole 8 is provided outside the innermost pipe 5 of the torch 4. An outermost tube 24 for supplying plasma gas to the tip of the torch 4 through the plasma gas supply hole 7 is provided on the outside thereof.
[0004]
The chamber 9 is provided with a discharge pipe 23 for introducing a finely atomized sample into the innermost pipe 5. The end of the innermost pipe 5 and the end of the discharge pipe 23 are fluidized by a clamp 6. It is connected to the.
When the sample 18 to be introduced is an organic solvent, carbon C in the sample introduced into the plasma 2 adheres to the tip of the torch 4 and the hole of the sampling cone 1, causing clogging and a decrease in sensitivity. In that case, the holding body 12 is provided with a gas inlet 21, oxygen gas is supplied from the inlet 21, mixed with the sample 18 in the chamber 9 and introduced into the plasma 2 to solve the above problem. Was. That is, carbon C in the sample 18 mixed with oxygen gas burns in the plasma 2 to become carbon dioxide CO ₂ or carbon monoxide CO. Carbon dioxide CO ₂ and carbon monoxide CO pass through the hole in the sampling cone 1 and diverge into the atmosphere, so they do not adhere to the tip of the torch 4 or the hole in the sampling cone 1.
[0005]
[Problems to be solved by the invention]
In the above prior art, the oxygen gas introduced from the gas inlet 21 provided in the holding body 12 and the organic solvent sprayed from the sprayer 13 attached to the holding body 12 are mixed in the chamber 9. At this time, if the organic solvent and oxygen gas in the chamber 9 are ignited due to static electricity, flashback, high frequency, or the like, the chamber 9 may burst, so the amount of oxygen gas introduced must be kept small. If the amount of introduced oxygen gas is less than the amount of oxygen gas required to sufficiently burn carbon C in the sample, the torch will not be sufficiently carbon dioxide CO ₂ or carbon monoxide CO. 4 Clogging of the tip and the hole of the sampling cone 1 will cause the sensitivity to decrease.
[0006]
The present invention solves the above problem, and the chamber 9 may burst even if oxygen gas is supplied in an amount necessary to suppress clogging of the tip of the torch 4 and the sampling cone 1 due to carbon C in the sample and a decrease in sensitivity. An object of the present invention is to obtain an inductively coupled plasma mass spectrometer that can prevent clogging and perform highly sensitive measurement.
[0007]
[Means for Solving the Problems]
The organic solvent sample introduction device for inductively coupled plasma mass spectrometer adopted by the present invention to achieve the above object has a branch pipe in the innermost tube of the torch, and introduces oxygen gas from which the flow rate can be controlled. It is characterized by doing.
The organic solvent sample introduction device for an inductively coupled plasma mass spectrometer of the present invention has a branch pipe in the innermost pipe of the torch, and introduces oxygen gas from the branch pipe. The flow rate of the nebulizer gas ejected from the nebulizer is sufficiently larger than the oxygen gas supplied from the branch pipe, and the flow of the nebulizer gas flows from the chamber holding the airtightness toward the tip of the torch that is the outlet. , Oxygen gas flows from the branch pipe to the torch and does not flow to the chamber. Therefore, the oxygen gas concentration in the chamber is extremely low.
[0008]
Since the oxygen gas concentration in the chamber can be reduced, even if a backfire occurs in the chamber, combustion does not occur in the chamber, and no explosion occurs. Therefore, the amount of oxygen gas necessary to suppress clogging of the torch tip and sampling cone due to carbon C and a decrease in sensitivity can be flowed, so that clogging can be prevented and high sensitivity measurement can be performed.
[0009]
【Example】
The present invention will be described in detail with reference to FIG. In FIG. 1, the components shown in FIG. 2 that have substantially the same function may be omitted here.
A torch 4 for generating inductively coupled plasma 2 is provided on the upper surface of the chamber 9, a cylindrical holder 12 is provided at the end of the chamber 9, and a sprayer 13 is attached to the holder 12. The joint surface between the torch 4 and the chamber 9 is connected by the clamp 6 so that leakage does not occur. An O-ring 11 is interposed at the joint between the chamber 9 and the holding body 12, and the gas in the chamber 9 is It is designed not to leak outside and is airtight. Note that the portion of the waste liquid hole 10 not shown in the figure has a siphon shape and is kept airtight with a liquid.
[0010]
A nebulizer gas supply pipe 14 and a sample supply pipe 16 are respectively connected to the nebulizer 13, and an end of the sample supply pipe 16 is immersed in a sample 18 in a sample container 17.
Now, when gas is supplied from the nebulizer gas supply unit 15, the gas passes through the nebulizer gas supply pipe 14, and the gas is ejected from the tip of the sprayer 13. Thereby, the internal pressure of the sprayer 13 is lowered, and the sample 18 in the sample container 17 is sucked by the negative pressure suction, and reaches the sprayer 13 through the sample supply pipe 16. Then, the sample 18 is jetted from the nebulizer 13 into the chamber 9 to form a mist-like sample.
[0011]
The finely atomized sample 18 is reached torch 4 through the discharge pipe 23 from the chamber 9, the other large particulate sample is discharged from the waste liquid hole 10 of the chamber 9. In the chamber 9, the atomized sample is classified.
On the other hand, the torch 4 is formed of a triple-structured quartz tube, and a gas (for example, argon gas) is supplied from the plasma gas supply hole 7 to the tip of the torch 4 through the outermost tube 24, and high frequency power (for example, By applying a frequency of 27.12 MHz and a power of 1.6 kW, plasma 2 is formed. An auxiliary gas supply hole 8 supplies auxiliary gas to the tip of the torch 4 through the intermediate pipe 8a.
[0012]
The sample 18 that reaches the torch 4 through the chamber 9 passes through the innermost tube 5 among the triple tubes of the torch 4. Now, when oxygen gas is supplied from the oxygen gas supply unit 20, oxygen gas is supplied from the branch pipe 22 provided in the innermost pipe 5 of the torch 4 through the oxygen gas supply pipe 19. Mixed with.
Here, the flow rate of the nebulizer gas ejected from the nebulizer 13 is sufficiently larger than the oxygen gas supplied from the branch tube 22, and the flow of the nebulizer gas is the tip of the torch 4 that is the exit from the chamber 9 that is kept airtight Since the oxygen gas flows in the direction, the oxygen gas flows from the branch pipe 22 toward the torch 4 and does not flow into the chamber 9. Therefore, the oxygen gas concentration in the chamber 9 is extremely low. Since the oxygen gas concentration in the chamber 9 can be lowered, even if a backfire occurs in the chamber 9, combustion does not occur in the chamber 9 and no explosion occurs.
[0013]
The sample 18 mixed with a sufficient amount of oxygen gas passes through the innermost tube 5 to reach the upper surface of the torch 4 and burns by the plasma 2, and the carbon C in the sample becomes carbon dioxide CO2 or carbon monoxide CO. It passes through the hole in the sampling cone 1 and diverges into the atmosphere. Other samples are ionized by the plasma 2. The ionized sample 18 passes through a hole in the sampling cone 1 and is analyzed by a mass spectrometer.
[0014]
In other words, the present invention introduces and transports a sprayer for atomizing a liquid sample, a chamber for classifying the atomized sample, and the classified sample and the plasma gas through respective fluidly separated tubes. The high frequency current that flows in the induction coil disposed around the tip of the tube into which the classified sample is introduced and transported (in the embodiment, the sample is the innermost tube 5 and the plasma gas flows to the outermost tube 24). A torch for forming plasma by electric power, a branch pipe for introducing oxygen gas whose flow rate can be controlled to a pipe for introducing and transporting the classified sample of the torch, and a sampling cone for passing the sample ionized by the plasma The inductively coupled plasma mass spectrometer is characterized by comprising a mass spectrometer that performs mass analysis of ions that have passed through the sampling cone.
It is obvious that a spectroscopic analyzer that separates plasma light can be provided in place of the sampling cone 1 and the mass spectroscope and can be employed in the inductively coupled plasma spectroscopic analyzer.
[0015]
【The invention's effect】
In the organic solvent sample introduction device for inductively coupled plasma analyzer, the present invention has a structure in which the inner tube of the torch has a branch pipe, and oxygen gas whose flow rate can be controlled can be introduced from the branch pipe. Have
(1) Oxygen gas can be prevented from entering the chamber as much as possible.
(2) Since the oxygen gas concentration in the chamber can be lowered, the oxygen gas flowed in an amount necessary to suppress clogging of the torch tip and sampling cone and deterioration of sensitivity due to carbon C without fear of rupture of the chamber be able to.
(3) Carbon C becomes carbon dioxide CO ₂ or carbon monoxide CO enough to prevent clogging and perform highly sensitive measurement.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a sample introduction device for an inductively coupled plasma mass spectrometer according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of a conventional sample introduction device for an inductively coupled plasma mass spectrometer.
[Explanation of symbols]
1 Sampling cone 2 Inductively coupled plasma 3 Inductive coil 4 Torch 5 Inner tube 6 Clamp 7 Plasma gas supply hole 8 Auxiliary gas supply hole
8a Intermediate tube 9 Chamber 10 Waste liquid hole 11 O-ring 12 Holder 13 Nebulizer 14 Nebulizer gas supply tube 15 Nebulizer gas supply unit 16 Sample supply tube 17 Sample container 18 Sample control device 19 Oxygen gas supply tube 20 Oxygen gas supply unit 21 Inlet 22 Branch pipe
23 discharge pipe
24 Outermost pipe

Claims (2)

A nebulizer for atomizing a liquid sample;
A chamber for classifying the sample atomized by the atomizer;
The sample classified in the chamber, the nebulizer gas, the plasma gas, and the auxiliary gas are introduced and transported through a triple-structured quartz tube that is fluidly separated, and plasma is formed at the tip of the tube. Torch,
A sampling cone through which the sample ionized by the plasma formed by the torch passes.
A mass spectrometer for mass-analyzing ions that have passed through the sampling cone;
With
Instead of introducing oxygen gas into the chamber, less oxygen gas than the nebulizer gas so as to prevent oxygen gas from flowing back into the chamber in the innermost tube of the torch through which the sample classified in the chamber passes. An inductively coupled plasma mass spectrometer characterized in that a branch pipe for introducing the gas is provided. A nebulizer for atomizing a liquid sample;
A chamber for classifying the sample atomized by the atomizer;
The sample classified in the chamber, the nebulizer gas, the plasma gas, and the auxiliary gas are introduced and transported through a triple-structured quartz tube that is fluidly separated, and plasma is formed at the tip of the tube. Torch,
A spectroscopic analyzer that splits the light of the plasma formed by the torch;
With
Instead of introducing oxygen gas into the chamber, less oxygen gas than the nebulizer gas so as to prevent oxygen gas from flowing back into the chamber in the innermost tube of the torch through which the sample classified in the chamber passes. An inductively coupled plasma spectroscopic analyzer, characterized in that a branch pipe for introducing a gas is provided.

Images