JP2557473B2 - Sample introduction device for inductively coupled plasma mass spectrometry - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a sample introduction device for inductively coupled plasma mass spectrometry, which is particularly attached to an inductively coupled plasma mass spectrometer with high sensitivity and high analytical accuracy. Related sample introduction device.

(Prior Art) Conventionally, a trace component in a sample has been analyzed by inductively coupled plasma mass spectrometry. This method atomizes a solution sample with a neprizer, introduces it into inductively coupled plasma, excites and ionizes it, and then mass separates the ions with a quadrupole mass filter to measure the content of impurities in the sample. To do. While such methods are generally sensitive in comparison with the ICP method and atomic absorption spectrometry is widely used as a microanalysis, low sample introduction efficiency into the plasma, the detection sensitivity is 10 ^-11 g to 10 ^{- 12} g is not enough,
It was difficult to apply it to minute samples such as semiconductor thin films.

Therefore, as a method for increasing the efficiency of introducing a sample into plasma and improving the detection sensitivity, a sample introducing device for evaporative vaporization is attached to the inductively coupled plasma mass spectrometer. Such a sample introduction device injects a solution sample into a cuvette made of a heat-generating substance or a cylindrical tube inserted in the cuvette, and heats it stepwise by applying an electric current or voltage in an inert gas stream. The target component in the sample is vaporized and vaporized and efficiently introduced into the plasma. It has been considered to use a high melting point metal such as graphite, tantalum, or tungsten as a heat generating substance for forming the cuvette or the tube.

However, when the sample is injected into the cuvette or the cylindrical tube, the sample easily moves from the central part of the cuvette or the central part of the tube (may be spilled), so that the temperature distribution inside the heated cuvette or inside the tube is Due to the difference, the following temperature conditions of evaporation of the sample vary depending on the analysis operation. As a result, there has been a problem that detection sensitivity and accuracy are significantly deteriorated.

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned conventional problems, and is to analyze an ultratrace amount in a sample in an inductively coupled plasma mass spectrometer with high accuracy and high sensitivity. The present invention is intended to provide a sample introduction device that enables the above.

[Structure of the Invention] (Means for Solving the Problems) The present invention relates to a heating furnace provided with an electrode made of a good electrical conductor and a cylindrical cuvette made of a heat-generating substance having a sample injection hole in the center, and a heating furnace for the cuvette. A sample introduction device composed of a gas control mechanism for flowing an inert gas from one end to the plasma torch part of the inductively coupled plasma mass spectrometer through the inside and the other end and controlling the flow of the inert gas. 2. The sample introduction device for inductively coupled plasma mass spectrometry according to claim 1, wherein at least one fine groove is provided on the circumference near the inner surface of the cuvette where the sample injection hole is located.

The above electrodes and cuvettes are electric good conductors at 2600 ~ 3000 ℃
Any material capable of withstanding the temperature of, for example, graphite or a heat-resistant metal such as tantalum, tungsten, rhenium, or zirconium is used. When the cuvette is made of graphite, a tube made of a refractory metal having a sample injection hole is inserted into the cuvette, and at least one tube is provided on the circumference near the inner surface of the tube where the sample injection hole is located. A structure in which the above-described fine grooves are provided may be used. The surface of the electrode, the surface of the cuvette, or the surface of the tube is preferably coated with a refractory metal oxide film or a refractory metal nitride film when analyzing elements (U, Th, rare earth elements, etc.) that easily generate carbides. . Examples of the refractory metal oxide include tantalum oxide and zirconium oxide, and examples of the refractory metal nitride include tantalum nitride, tungsten nitride, hafnium nitride, zirconium nitride, and titanium nitride. The thing etc. can be mentioned.
The coating of such a refractory metal oxide film or refractory metal nitride film may be performed by any method such as a CVD method, a thermal oxidation method, a sputter deposition method, and a coating-firing method, but considering the simplicity of the operation. The coating-firing method is preferred.

Examples of the above-mentioned inert gas include argon and helium, and if necessary, a small amount of hydrogen may be added to the gas.

At least one fine groove is provided on the circumference near the inner surface of the cuvette where the sample injection hole is located or near the inner surface of the tube.
More than one is provided, but it is particularly preferable to provide a fine groove at the position of the cuvette or tube where the sample naturally drops when the sample is injected from the injection hole in a state where the cuvette or tube is horizontal.

The width or depth of the fine groove is preferably as large as possible from the viewpoint of fixing the sample at a predetermined position on the inner surface of the cuvette or the tube and suppressing the movement, but if it is too large, the cuvette is heated when heated. Alternatively, since the tube is easily damaged, it is desirable to set the thickness in the range of 1 to 10 μm for practical use. When the inner surface of the cuvette or tube is coated with a refractory metal oxide film or refractory metal nitride film, the depth of the fine groove is made shallower than the thickness of the oxide film or nitride film, and the inner surface of the groove is reduced. It is advisable not to expose the cuvette or the tube itself. The shape of the fine groove is arbitrary.

As the means for forming the fine grooves, for example, a hard material with a sharp tip (for example, cemented carbide, ceramics, glass, etc.)
A method of mechanically scratching a predetermined part of the inner surface of the cuvette or tube with a jig consisting of, a method of physically removing a predetermined part of the inner surface of the cuvette or tube by discharge or laser, a predetermined part of the inner surface of the cuvette or tube by acid etching, etc. It is possible to employ a method of chemically removing However, since the inner surface of the cuvette or tube after the formation of the fine grooves is contaminated with impurities, the cuvette or tube is subjected to acid cleaning treatment or high temperature treatment in an inert gas stream such as argon (2600 to 3000) before use.
C.) to reduce impurities as much as possible.

(Operation) According to the present invention, at least one fine groove is provided on the circumference of the inner surface of the cuvette where the sample injection hole is located or inserted into the cuvette and near the inner surface of the tube where the sample injection hole is located. Thus, a part of the sample injected from the injection hole first enters the fine groove, and then the remaining sample is also retained around the fine groove due to the surface tension. Therefore, even if an inert gas is circulated inside the cuvette or the tube, or the cuvette or the tube is slightly inclined, the sample can be prevented from moving from the set position of the cuvette or the tube. As a result, even if there is a temperature distribution in the cuvette or tube, the sample injected into the cuvette or tube can be stopped at a fixed position, so the sample should always be heated and evaporated under the same temperature condition. Therefore, an inductively coupled plasma mass spectrometer into which an evaporated and vaporized sample is introduced can analyze ultra-trace components in the sample with high accuracy and high sensitivity.

Further, by coating the surface of the cuvette and the surface of the electrode, which are brought into contact with the heated inert gas or the vaporized sample gas, with an oxide film or a nitride film of a refractory metal, graphite is used as a base material for the cuvette or the like. When an analysis is performed using, it is possible to prevent an element (U, Th, etc.) that easily forms a carbide in the sample from reacting with graphite to form a carbide. As a result, the ionization efficiency can be significantly improved and the memory effect can be eliminated. On the other hand, when a refractory metal is used as a base material for a cuvette or the like, U or Th contained as impurities in the refractory metal evaporates due to the barrier action of the refractory metal oxide film or nitride film. Can be suppressed. Moreover, the vaporization start time of U or Th in the refractory metal can be delayed from the vaporization start time of U or Th in the sample by coating the oxide film or the nitride film of the refractory metal. Therefore, U in the sample
It is possible to temporally separate the ion spectrum due to Th and Th and the ion spectrum due to U and Th in the heat-resistant metal as the base material. Therefore, it is possible to analyze U and Th, which are ultratrace components in the sample in the inductively coupled plasma mass spectrometer, with high sensitivity, high accuracy and speed.

Further, the cuvette is formed of graphite, and a tube having a sample injection hole is inserted into the cuvette,
By providing at least one fine groove on the circumference of the inner surface of the tube near the injection hole,
The above-mentioned inductively coupled plasma mass spectrometer can analyze ultra-trace components in a sample with high accuracy and high sensitivity, and can reduce the size of the vaporization vaporization part space of the sample introduction device. That is, when the cuvette is made of a heat-resistant metal, the sample can be analyzed with high accuracy and high sensitivity when measuring elements (U, Th, etc.) that easily form carbides, but the heat-resistant metal has a good thermal conductivity. Therefore, the space for evaporative evaporation of the sample introduction device becomes large due to the need for heat insulation. Therefore, by forming the cuvette with graphite having excellent heat insulating properties, it is possible to reduce the space of the evaporation / vaporization section of the sample introduction device. In this case, not only the cuvette but also the electrode is made of graphite, so that the size can be further reduced. However, if the cuvette is made of graphite, elements that easily form carbides in the sample (such as U and Th)
When U is measured, U or Th reacts with graphite to generate a carbide, which causes a decrease in ionization efficiency and a memory effect. Therefore, by inserting a tube made of a refractory metal into the cuvette and evaporating and evaporating the sample here, while eliminating the memory effect and maintaining a high ionization efficiency, the evaporative evaporation space of the sample introduction device is maintained. The size can be reduced.

Further, by inserting a cylindrical tube of a refractory metal whose surface is coated with a refractory metal oxide film or a nitride film into the graphite cuvette, the refractory metal oxide film or nitride film is inserted. By the barrier action of, it is possible to suppress evaporation and vaporization of U and Th contained as impurities in the high melting point metal that is the tube base material. Moreover, by coating the oxide film or the nitride film of the refractory metal, the vaporization start time of U and Th in the refractory metal that is the tube base material is set to be smaller than the vaporization start time of U and Th in the sample. Since it can also be delayed, the ion spectrum due to U or Th in the sample and the ion spectrum due to U or Th in the refractory metal that is the tube base material can be temporally separated. Therefore, by inserting a tube made of a refractory metal whose surface is coated with a refractory metal oxide film or a nitride film into the cuvette and evaporating and evaporating the sample here, the ionization efficiency is improved and the memory effect is improved. With more reliable prevention, it is possible to perform a more accurate analysis, and it is possible to reduce the size of the space in the evaporative vaporization section of the sample introduction device.

Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.

Example 1 FIG. 1 is a schematic sectional view showing a sample introduction device for inductively coupled plasma mass spectrometry used in this example. 1 in the figure
Is a cuvette made of a heating substance, and a sample injection hole 2 is opened in the upper center of the cuvette 1. In the cuvette 1, a cylindrical tube 3 made of a high melting point metal is provided.
Is inserted so that the sample injection hole 4 opened at the upper center thereof matches the injection hole 2 of the cuvette 1. In the vicinity of the inner surface of the tube 3 where the injection hole 4 is located,
As shown in FIG. 2, fine grooves 5 are provided over the entire circumference. Further, the cuvette 1 has electrodes 6a, 6b made of a good electric conductor divided in a direction perpendicular to the axial direction.
The cuvette 1 is surrounded by the edges of the cuvette 1 and is in contact with and supported by the inner surfaces of the electrodes 6a and 6b, respectively. An insulating material layer (not shown) for electrically insulating the electrodes 6a and 6b is interposed between the divided surfaces of the electrodes 6a and 6b. A pipette insertion hole 7 is opened in one of the electrodes 6a. The respective electrodes 6a, 6b are surrounded by electrode blocks 8a, 8b made of a good electric conductor divided in a direction perpendicular to the axial direction, and the outer peripheral surfaces of the respective electrodes 6a, 6b are respectively electrode blocks 8a, 8a. It is in contact with and supported by the inner peripheral surface of 8b. An insulating material layer (not shown) for electrically insulating the electrode blocks 8a and 8b is interposed between the divided surfaces. The electrode blocks 8a, 8b are provided with cooling water passages 9a, 9b for cooling the blocks 8a, 8b. A quartz pipe 10a serving as a carrier gas outlet and a quartz pipe 10b serving as a carrier gas inlet are inserted into the electrode blocks 8a and 8b, respectively. Also, the electrode block 8
Carrier gas external flow channels 11a and 11b are respectively formed from a and 8b to the electrodes 6a and 6b, and the quartz pipes 10a and 1b are provided.
Carrier gas internal channels 12a and 12b are formed in the electrode blocks 8a and 8b near the insertion portion of 0b. Quartz pipe 10b as carrier gas inlet and carrier gas internal flow path 1
2a and 12b are used to flow carrier gas at independent flow rates in the steps of drying and ashing the sample in the tube 3 and evaporative vaporization. The cuvette 1, the tube 3, the electrodes 6a and 6b, the electrode blocks 8a and 8b, and the like constitute a heating furnace.

Reference numeral 13 in the figure is a unitized gas control mechanism. The gas control mechanism 13 includes a first solenoid valve 15 arranged on the inert gas inlet 14 side. This solenoid valve 15
It is connected to a pressure regulator 16 and a pressure meter 17 is connected to the regulator 16. The pressure regulator 16 and the pressure meter 17 are adjusted to proper pressure in advance. Further, a pipe portion between the solenoid valve 15 and the pressure regulator 16 is connected to a pressure switch 18 for detecting whether or not the pressure of the inert gas introduced from the inert gas inlet 14 is sufficient. There is. When the pressure detected by the pressure switch 18 is below a predetermined value, the detection signal is fed back to the control unit (not shown) of the power supply system of the electrode blocks 8a and 8b, and the cuvette 1 and the like are excessively fed. Fever (around 3000 ℃)
It also serves to prevent oxidization. On the rear side of the pressure regulator 16, the pressure regulator 16 is branched into three directions and connected to the flow rates 19 to 21 with a flow rate adjusting function. The first flow meter 19 is connected to the carrier gas external flow paths 11a and 11b of the heating furnace. The second flow meter 20 is connected to the carrier gas internal flow paths 12a and 12b of the heating furnace via a second electromagnetic valve 22. The third flow meter 21 is a quartz pipe which is a carrier gas inlet of the heating furnace via a third solenoid valve 23.
It is linked to 10b. A fourth solenoid valve 24 is provided in the piping system connecting the heating furnace and the plasma torch (not shown) of the inductively coupled plasma mass spectrometer.

Next, the operation of the sample introduction device shown in FIG. 1 will be described.

First, the sample is dropped into the cylindrical tube 3 through the pipette insertion hole 7 and the sample injection holes 2 and 4 with the second to fourth electromagnetic valves 22 to 24 closed. Sample dropped at this time
As shown in FIG. 2, 25 penetrates the fine groove 5 located immediately below the sample injection hole 4 and is retained in the groove 5 and its periphery. Subsequently, the electrode blocks 8a and 8b are energized from the power supply according to the heating programming of the control unit, and the electrode blocks 8a and 8b are energized.
A voltage is applied to both ends of the cuvette 1 through electrodes 6a and 6b connected to 8a and 8b to heat the cuvette 1 and the tube 3 to a predetermined temperature to dry and incinerate the sample 25 in the tube 3. 2. The third and third solenoid valves 22 and 23 are opened to supply an inert gas (carrier gas) to the internal passages 12a and 12b of the heating furnace and the quartz pipe 10b as an inlet. As a result, water vapor and coexisting substances generated in the steps of drying and ashing the sample 25 are removed to the outside of the heating furnace through the sample injection holes 4 and 2 and the pipette insertion hole 7 together with the carrier gas. Then
After closing the pipette insertion hole 7 and the sample injection holes 2 and 4 with a graphite stopper, a boron nitride stopper, or a heat-resistant metal stopper (not shown) whose surface is covered with a refractory metal oxide film or nitride film, the cuvette 1 is turned on to generate heat at a higher temperature to evaporate the target component in the sample 25 and simultaneously
The electromagnetic valve 24 is opened to introduce the vaporized and vaporized target component into the plasma torch of the inductively coupled plasma mass spectrometer, and excites and ionizes it. The ions are measured by mass separation using a quadrupole mass filter, and the concentration of the target component is calculated from the ion intensity using a calibration curve. After the above operation is completed and the cuvette 1 and the tube 3 are cooled, the second to fourth electromagnetic valves 22 to 24 are closed, the sample is injected again, and the same operation is repeated to perform the measurement.

Since fine grooves 5 are provided around the entire circumference of the cylindrical tube 3 made of refractory metal near the inner surface where the injection hole 4 is located, as shown in FIG. The sample 25 can be prevented from moving from the position of the fine groove 5. As a result, the sample 25 can always be evaporated and vaporized under the same temperature condition, so that an ultratrace component in the sample can be analyzed with high accuracy and high sensitivity in the inductively coupled plasma mass spectrometer.

In fact, it was confirmed by using the sample introduction device for inductively coupled plasma mass spectrometry of Example 1 that the ultratrace component in the sample could be analyzed with high precision by conducting the following experiment.

Example 1-1 Electrodes 6a and 6b made of graphite, and cuvette 1 made of graphite having an outer diameter of 8 mmφ, an inner diameter of 6 mmφ, a length of 28 mm, and one sample injection hole of 2 mmφ in the central portion were cylindrical. Tube 3 has an outer diameter of 5.5 mmφ, an inner diameter of 4.5 mmφ, a length of 26 mm, and a sample injection hole of 2 mmφ in the center.
Each of them was made of high-purity tungsten. The electrodes 6a and 6b, the cuvette 1 and the cylindrical tube 3 were coated with a tungsten nitride film having a thickness of about 20 μm on the surfaces of the portions in contact with the heated inert gas and the vaporized sample gas. The tungsten nitride film was coated by applying an organotungsten compound on the surface of a predetermined member and then firing it in a nitrogen atmosphere. In addition, the width and the depth of the cylindrical tube 3 are about 10 along the entire circumference in the vicinity of the inner surface where the sample injection hole 4 is located.
One V-shaped fine groove 5 of μm was formed. This fine groove 5
Was formed by mechanically scratching the tungsten nitride film on the inner surface of the tube with a high-purity tungsten jig having a sharp tip, and then subjected to a high temperature treatment at 2900 ° C. in an argon gas stream.

Comparative Example 1-1 A sample introduction device similar to that in Example 1-1 was assembled except that fine grooves were not formed on the inner surface of the tungsten cylindrical tube coated with the tungsten nitride film.

Comparative Example 1-2 Except that the electrode, the cuvette and the cylindrical tube made of tungsten were not covered with the tungsten nitride film, and the fine grooves were not formed on the inner surface of the tube, the above-mentioned Example 1-
A sample introduction device similar to that of No. 1 was assembled.

Therefore, the present Example 1-1 and Comparative Examples 1-1 and 1-2
Using the sample introduction device and the inductively coupled plasma mass spectrometer of uranium standard solution 100 pg / ml sample 10μ and the same standard solution 0 pg / ml sample 10μ, measure the ionic strength under the following conditions.
The measurement was performed 10 times each.

Carrier gas in sample introduction device; Argon at 4.0 / min.

 Drying in the sample introduction device; 150 ° C, 30 sec.

 Ashing in the sample introduction device; 1000 ° C, 30 sec.

 Evaporative vaporization in sample introduction device; 2800 ° C, 7 sec.

 Frequency of high frequency power supply in plasma torch; 27.12MHz.

 High frequency output of high frequency power supply with plasma torch; 1.3kW.

 Cooling gas with plasma torch; 15 / min.

 Plasma gas with plasma torch; 0.8 / min.

As a result, in Example 1-1, the uranium standard solution 100 p
The average ionic strength of the sample of g / ml is 520, the accuracy is ± 7%, the average ionic strength of the sample of 0 pg / ml of the standard solution is 8, the accuracy is ±
It was 6%. On the other hand, in Comparative Example 1-1, the average ionic strength of the sample of 100 pg / ml of uranium standard solution is 390, the accuracy is ± 15%, the average ionic strength of the sample of 0 pg / ml of the standard solution is 8, and the accuracy is ± 6. %, The sample moves from a predetermined position on the inner surface of the tube (immediately below the sample injection hole) due to the absence of fine grooves on the inner surface of the cylindrical tube, and the uranium ionic strength changes because the temperature conditions during evaporation and vaporization fluctuate. Is reduced,
The accuracy also decreased. Further, in Comparative Example 1-2, the average ionic strength of a sample of 100 mg / ml uranium standard solution was 310, and the accuracy was ± 8.
%, The average ionic strength of the standard solution of 0 pg / ml was 45, the accuracy was ± 7%, and the standard solution was prepared by mixing the vaporized uranium from the tungsten cylindrical tube not covered with the tungsten nitride film. Ionic strength of uranium was also measured in the zero sample.

Example 1-2 The electrodes 6a, 6b made of graphite, the cuvette 1 made of graphite having an outer diameter of 8 mmφ, an inner diameter of 6 mmφ, a length of 28 mm and one sample injection hole of 2 mmφ in the central portion were cylindrical. Tube 3 has an outer diameter of 5.5 mmφ, an inner diameter of 4.5 mmφ, a length of 26 mm, and a sample injection hole of 2 mmφ in the center.
Ones each made of high-purity tantalum were used. In addition, a V-shaped fine groove 5 having a width and a depth of about 10 μm is formed on the entire circumference of the inner surface of the cylindrical tube 3 where the sample injection hole 4 is located and on the whole circumference 500 μm left and right thereof. 3 in total were formed. These fine grooves 5 are formed by mechanically scratching the inner surface of the tube with a jig made of high-purity tantalum with a sharp tip, and then at 2900 ° C. in an argon gas stream.
Was subjected to high temperature treatment.

Comparative Example 1-3 A sample introducing device similar to that of the above Example 1-2 was assembled except that fine grooves were not formed on the inner surface of the tantalum cylindrical tube.

Then, using the sample introduction apparatus and the inductively coupled plasma mass spectrometer of the present Example 1-2 and Comparative Example 1-3, a 10 μm sample of the europium standard solution 100 pg / ml and the same standard solution were used.
Ashing conditions for 1μC, 30sec for 0μg / ml sample 10μ
Other than the above, the ionic strength was measured 10 times under the same conditions as in Example 1-1. As a result, in Example 1-2, the average ionic strength of the sample of the europium standard solution 100 pg / ml was 470, the accuracy was ± 6%, and the average ionic strength of the sample of the standard solution 0 pg / ml was 3, the accuracy was ± 5%. there were. On the other hand, in Comparative Example 1-3, the average ionic strength of the sample of the europium standard solution 100 pg / ml is 380, the accuracy is ± 14%, and the standard solution is 0 pg / ml.
Sample has an average ionic strength of 3 and an accuracy of ± 5%, and because the inner surface of the cylindrical tube is not provided with fine grooves,
The sample moved from a predetermined position on the inner surface of the tube (immediately below the sample injection hole), and the temperature condition during evaporation and vaporization fluctuated, so that the ionic strength of europium decreased and the accuracy also decreased.

Thus, it can be seen that the sample introduction apparatus of the present Example 1 greatly improves the analysis accuracy and sensitivity in the measurement of uranium and europium as compared with the inductively coupled plasma mass spectrometry method in which the conventional evaporative vaporization method is also used. In addition, the sample introduction device of the present Example 1 can be used also for an inductively coupled plasma optical emission spectrometer, and greatly improves the analysis accuracy and sensitivity even when compared with the conventional inductively coupled plasma optical emission spectrometer which also uses the evaporative vaporization method. be able to.

Example 2 Electrodes 6a and 6b were made of graphite, and cuvette 1 was made of graphite having an outer diameter of 8 mmφ, an inner diameter of 6 mmφ, a length of 28 mm, and one sample injection hole of 2 mmφ in the central portion. In addition, the sample injection hole 2 of the cuvette 1 without inserting a cylindrical tube into the cuvette 1.
The width and depth are both about the entire circumference of the inner surface where
One V-shaped fine groove of 10 μm was formed. The fine grooves were formed by mechanically scratching the inner surface of the cuvette with a high-purity tantalum jig having a sharp tip, and then subjected to high temperature treatment at 2900 ° C. in an argon gas stream.

Comparative Example 2 A sample introducing device similar to that in Example 2 was assembled except that fine grooves were not formed on the inner surface of the cuvette made of graphite.

Then, using the sample introduction apparatus and the inductively coupled plasma mass spectrometer of Example 2 and Comparative Example 2, a copper standard solution was used.
100 μg / ml sample 10 μ and the same standard solution 0 μg / ml sample 10 μ
The ion velocity was measured 10 times each under the same conditions as in Example 1-1 except that the ashing condition was set to 800 ° C. for 30 seconds. As a result, in Example 2, the average ionic strength of the sample of the copper standard solution 100 pg / ml was 420, the accuracy was ± 7%, and the standard solution was 0 pg.
The average ionic strength of the / ml sample was 6, and the accuracy was ± 6%. On the other hand, in Comparative Example 2, the average ionic strength of the copper standard solution 100 pg / ml sample was 370, the accuracy was ± 11%, and the standard solution was 0%.
The pg / ml sample has an average ionic strength of 6 and an accuracy of ± 6%. Since the micro groove is not provided on the inner surface of the cuvette, the sample moves from a predetermined position on the inner surface of the cuvette (just below the sample injection hole) and evaporates. The ionic strength of copper decreased due to the change in temperature condition during vaporization, and the accuracy also decreased.

As described above, it is understood that the sample introduction device of the second embodiment significantly improves the analysis accuracy and sensitivity in the copper measurement in comparison with the inductively coupled plasma mass spectrometry method in which the conventional evaporative vaporization method is used together. In addition, the sample introduction device of the second embodiment can be applied to an inductively coupled plasma optical emission spectrometer, and significantly improves the analysis accuracy and sensitivity even when compared with the conventional inductively coupled plasma optical emission spectrometer that uses the evaporative vaporization method together. be able to.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a sample introduction device capable of analyzing an ultratrace component in a sample in an inductively coupled plasma mass spectrometer with high accuracy and high sensitivity.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a sample introduction device for inductively coupled plasma mass spectrometry showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the cylindrical tube of FIG. 1 ... cuvette, 2, 4 ... sample injection light, 3 ... cylindrical tube, 5 ... fine groove, 6a, 6b ... electrode, 8a, 8b ...
… Electrode block, 11a, 11b …… Carrier gas external flow path,
12a, 12b ... Carrier gas internal flow path, 13 ... Gas control mechanism, 18 ... Pressure switch, 22-24 ... Solenoid valve, 25 ... Sample.

Claims (2)

(57) [Claims] 1. A heating furnace provided with an electrode made of a good electric conductor and a cylindrical cuvette made of a heat-generating substance having a sample injection hole in the center, and from one end of the cuvette to the inside and the other end thereof. In a sample introduction device comprising a gas control mechanism for controlling an inert gas flow and an inert gas flow in a plasma torch part of an inductively coupled plasma mass spectrometer, in the vicinity of the inner surface of the cuvette where the sample injection hole is located A sample introduction device for inductively coupled plasma mass spectrometry, characterized in that at least one fine groove is provided on the circumference of. 2. A cuvette made of graphite,
A tube made of a refractory metal having a sample injection hole is inserted into the cuvette, and at least one fine groove is provided on the circumference of the tube near the inner surface of the tube where the sample injection hole is located. The sample introduction device for inductively coupled plasma mass spectrometry according to claim 1.