JP2598073B2 - Sample introduction device for inductively coupled plasma mass spectrometry - Google Patents

Description

The present invention relates to a sample introduction device for inductively coupled plasma mass spectrometry, and more particularly to an inductively coupled plasma mass spectrometer for measuring ultratrace components. The present invention relates to improvement of an attached sample introduction device.

(Prior Art) Conventionally, a trace component in a sample has been analyzed by inductively coupled plasma mass spectrometry. In this method, a solution sample is atomized by a nebulizer, introduced into an inductively coupled plasma, and excited and ionized. Then, the ions are mass-separated by a quadrupole mass filter, and the contents of U and Th in the sample are measured. Is measured. Such a method is generally higher in sensitivity than the inductively coupled plasma emission method or the atomic absorption spectrometry method which is currently frequently used as a microanalysis, but the sample introduction efficiency into the plasma is low, and the detection sensitivity is 10 ⁻¹¹ g to 10 ⁻¹¹ g. Since it was insufficient at 10 ^-12 g, it was difficult to apply it to a very small amount of sample such as a semiconductor thin film.

Therefore, in recent years, as a method of improving the efficiency of introducing a sample into plasma and improving the detection sensitivity, an inductively coupled plasma mass spectrometer has been provided with a sample introducing device for evaporative vaporization. Such a sample introduction device places a solution sample on a heating substance, applies current or voltage in an inert gas stream, heats the sample step by step, evaporates and vaporizes a target component in the sample, and efficiently converts it into plasma. It is to be introduced.
As a heating substance provided in the sample introduction device, a high melting point metal such as graphite, tantalum, and tungsten is generally used.

However, when introducing the vaporized sample gas into the plasma torch, the sample gas is adsorbed at the connection between the plasma torch and the cuvette (made of a heat generating substance), so that the efficiency of introducing the target component is reduced, A memory effect in which the component remains appears. In particular, the higher the boiling point of the target component, the greater the effect. As a result, there has been a problem that the detection sensitivity and accuracy are remarkably deteriorated. In addition, if sample gas or the like is adsorbed and contaminated at the connection portion between the plasma torch portion and the cuvette, the connection portion needs to be removed, cleaned, connected and adjusted, the operation becomes extremely complicated, and maintenance takes a long time. There was a problem.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned conventional problems, and is capable of analyzing ultra-trace components in a sample in an inductively coupled plasma mass spectrometer with high sensitivity, high accuracy, and high speed. It is an object of the present invention to provide a sample introduction device capable of performing the measurement.

[Constitution of the Invention] (Means for Solving the Problems) The present invention relates to a heating furnace provided with an electrode made of an electric conductor and a cylindrical cuvette made of a heating substance having a sample injection hole in a central portion, A sample control device configured to flow an inert gas from one end to the plasma torch portion of the inductively coupled plasma mass spectrometer through the inside and the other end, and to control a flow of the inert gas. The connection member between the cuvette and the plasma torch portion is formed of a transparent heat-resistant material, and the heating means is provided outside the connection member so that a portion extending in the longitudinal direction of the connection member can be visually observed from the outside. A sample introduction device for inductively coupled plasma mass spectrometry, which is provided.

The above electrodes and cuvettes are electric good conductors at 2600 ~ 3000 ℃
Any material that can withstand the temperature of
For example, it is formed of graphite or a heat-resistant metal such as tantalum, tungsten, rhenium, and zirconium. It is desirable that the electrode surface and the cuvette surface be covered with a high melting point metal oxide film or a high melting point metal nitride film. Examples of the high melting point metal oxide include tantalum oxide, tungsten oxide, and zirconium oxide. Examples of the high melting point metal nitride include tantalum nitride, tungsten nitride, hafnium nitride, and zirconium nitride. And titanium nitride. The coating of the high melting point metal oxide film and the high melting point metal nitride film is performed by CVD, thermal oxidation, sputter deposition,
Although any method such as a coating and baking method may be used, the coating and baking method is preferable in view of the simplicity of the operation.

Examples of the inert gas include argon and helium, and a small amount of hydrogen may be added to the gas as needed.

As the transparent heat-resistant material forming the connection member between the cuvette and the plasma torch portion, for example, quartz or sapphire can be used.

The length of the connection member is desirably as short as possible from the viewpoint of suppressing the evaporation and vaporization of the sample gas from being condensed and adsorbed on the connection member, or preventing the sample gas flow from being disturbed or diluted. In practice, it may be set to 10 cm or less. Further, the number of the connection members is not limited to one, and a plurality of connection members may be provided in parallel, and a connecting portion of the connection members may be provided with a sample gas flow switching member.

The type of the heating means is not limited, such as electric resistance heating and infrared heating. The heating temperature of the connection member by the heating means is preferably set to the highest possible temperature from the viewpoint of suppressing the evaporation and evaporation of the sample gas from condensing and adsorbing to the connection member. 100 ~ 250 ℃
Should be set to.

(Operation) According to the present invention, by providing a heating means outside the connecting member between the cuvette and the plasma torch portion, the temperature of the connecting member can be easily increased, and the evaporated sample flowing through the connecting member can be obtained. Condensation and adsorption of gas can be suppressed. As a result, the efficiency of introducing the target component into the plasma torch portion of the inductively coupled plasma mass spectrometer can be greatly improved, and the memory effect can be eliminated. Therefore, an ultra-trace component in a sample in an inductively coupled plasma mass spectrometer can be analyzed with high sensitivity and high accuracy.

Further, the connecting member is formed of a transparent acid-resistant material, and the heating means is provided outside the connecting member so that a portion extending in a longitudinal direction of the connecting member can be visually observed from the outside. It is possible to easily monitor the adsorption state of the sample gas from the outside. Specifically, when the sample gas is adsorbed, the connection member is colored or condensate adheres, so that it can be visually discriminated. As a result, the analysis can be always performed in a state where the sample gas is not adsorbed to the connecting member.

Further, if the length of the connecting member is set to 10 cm or less, it is possible to suppress the evaporation and vaporization of the sample gas from being condensed and adsorbed on the connecting member, or to suppress the flow of the sample gas from being disturbed or diluted.

Further, by providing a plurality of connection members of the cuvette and the plasma torch portion in parallel, and by providing a sample gas flow switching member at the connection portion of the connection members,
When one connecting member is contaminated by the adsorption of the sample gas or the like, the sample gas can be flowed to the other connecting member by the flow path switching member. Therefore, detachment, cleaning, connection, and adjustment of the conventional connecting member are performed. Becomes unnecessary, and the analysis operation can be performed simply and continuously without interruption.

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. The cuvette 1 is surrounded by electrodes 5a and 5b composed of electric conductors divided in a direction perpendicular to the axial direction, and both peripheral edges of the cuvette 1 contact and support the inner surfaces of the electrodes 5a and 5b, respectively. Have been. An insulating material layer (not shown) for electrically insulating the electrodes 5a and 5b from each other is provided on the divided surfaces. A pipette insertion hole 6 is opened in one electrode 5a. The cuvette 1
The surface, the surface of the tube 3, and the surfaces of the electrodes 5a and 5b are covered with an oxide film or a nitride film of a refractory metal. The electrodes 5a and 5b are surrounded by electrode blocks 7a and 7b made of electric conductors divided in a direction perpendicular to the axial direction, and the outer peripheral surfaces of the electrodes 5a and 5b are respectively covered by the electrode blocks 7a and 5b.
It is in contact with and supported by the inner peripheral surfaces of a and 7b. An insulating material layer (not shown) for electrically insulating the electrode blocks 7a and 7b from each other is provided on the divided surfaces. The electrode blocks 7a and 7b are provided with cooling water passages 8a and 8B for cooling the blocks 7a and 7b. The electrode blocks 7a and 7b have a quartz pipe 9a serving as a carrier gas outlet and a quartz pipe 9b serving as a carrier gas inlet.
Are inserted respectively. Further, the electrode blocks 7a, 7b
To the electrodes 5a and 5b.
Carrier gas internal flow paths 11a and 11b are formed in the electrode blocks 7a and 7b near the insertion portions of the quartz pipes 9a and 9b, respectively. Quartz pipe 9b as carrier gas inlet and carrier gas internal flow paths 11a, 11b
Is used for flowing a carrier gas at an independent flow rate in the drying and incineration stage and the evaporative evaporation stage of the sample in the tube 3. The heating furnace is constituted by the cuvette 1, the tube 3, the electrodes 5a and 5b, the electrode blocks 7a and 7b, and the like.

Between the one quartz pipe 9a and a plasma torch part (not shown) of the inductively coupled plasma mass spectrometer, for example, three connecting members made of quartz glass, which is a transparent and acid-resistant material, having a length of 10 cm the following connection tube 12 ₁ to 12 ₃ are provided in parallel. These connecting tubes 12 ₁ -12 ₃
Of the outer, infrared heaters _{131-134 3} as heating means are disposed, respectively. That is, the infrared heaters 13 ₁ to 1
3 ₃ longitudinally over the portion of the connection tube 12 ₁ to 12 ₃ wherein the outside of each connecting tube 12 ₁ to 12 ₃ are respectively visibly disposed externally. In addition, each connection tube
The connecting portion of 12 ₁ to 12 _3, the three-way switching valves 14a as the channel switching member, 14b are respectively interposed.

Reference numeral 15 in the drawing denotes a unitized gas control mechanism. The gas control mechanism 15 includes a first solenoid valve 17 disposed on the side of the inert gas inlet 16. The solenoid valve 17 is connected to a pressure regulator 18, and a pressure meter 19 is connected to the regulator 18. The pressure regulator 18 and the pressure meter 19 are adjusted to an appropriate pressure in advance. Also,
A piping section between the solenoid valve 17 and the pressure regulator 18 is connected to a pressure switch 20 for detecting whether the pressure of the inert gas introduced from the inert gas inlet 16 is sufficient. When the pressure detected by the pressure switch 20 is equal to or lower than a predetermined value, a detection signal is fed back to a control unit (not shown) of a power supply system of the electrode blocks 7a and 7b, and the cuvette 1 and the like are excessively moved. It prevents heat from being oxidized due to heat generation (around 3000 ° C). On the downstream side of the pressure regulator 18, it is branched into three directions and connected to flow meters 21 to 23 having a flow rate adjusting function. First flow meter
21 is connected to the carrier gas external flow paths 10a and 10b of the heating furnace. The second flow meter 22 is connected to the carrier gas internal flow paths 11a and 11b of the heating furnace via a second solenoid valve 24. A third flow meter 23 is connected via a third solenoid valve 25 to a quartz pipe 9b serving as a carrier gas inlet of the heating furnace.
It is connected to.

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

First, a sample is dropped into the cylindrical tube 3 through the pipette insertion hole 6 and the sample injection holes 2 and 4 with the second and third solenoid valves 24 and 25 closed. Subsequently, according to the heating programming of the control unit from the power supply, the electrode block 7a,
7b, a voltage is applied to both ends of the cuvette 1 through the electrodes 5a, 5b connected to the electrode blocks 7a, 7b to cause the cuvette 1 and the tube 3 to generate heat to a predetermined temperature, and the sample 26 in the tube 3 is discharged. Drying and incineration, second,
By opening the third solenoid valves 24 and 25, an inert gas (carrier gas) is supplied to the internal channels 11a and 1b of the heating furnace and the quartz pipe 9b as an inlet. As a result, water vapor and coexisting substances generated at the stage of drying and incineration of the sample 26 are removed out of the heating furnace through the sample injection holes 4 and 2 and the pipette insertion hole 6 together with the carrier gas. Next, the pipette insertion hole 6 and the sample injection holes 2 and 4 were closed with a graphite plug, a boron nitride plug or a heat-resistant metal plug (not shown) whose surface was covered with a high melting point metal oxide film or nitride film. Later, cuvette 1
Increase the energizing voltage to the sample to generate heat at a higher temperature.
Evaporate and evaporate the target component inside, and at the same time, three-way switching valve 14
a, open the 14b, it is introduced for example evaporation vaporized target component to an inductively coupled plasma mass spectrometer the plasma torch through the connection tube 12 ₁ which is heated by the infrared heaters 13 _1, excited ionized. 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 solenoid valve 2
4, 25 and the three-way switching valves 14a and 14b are closed, the sample is injected again, and the same operation is repeated to perform measurement.

Upon introduction into a plasma torch unit through the connection tube 12 ₁ of vaporized sample gas as described above, by providing the infrared heater 13 ₁ as a heating means outside of the connecting tube 12 _1, the temperature of the connecting tube 12 ₁ can be easily increased, it can suppress the sample gas evaporates flowing through the tube 12 ₁ is adsorbed to condense. As a result, the efficiency of introducing the target component into the plasma torch of the inductively coupled plasma mass spectrometer can be greatly improved,
The memory effect can be eliminated. Further, by forming of a material excellent in transparency and acid resistance of the continuous tube 12 ₁ (e.g., quartz glass), it is possible to easily monitor the adsorption state of the sample gas in the connection tube 12 ₁ from outside.
As a result, the analysis can be always performed in a state where the sample gas is not adsorbed to the connecting member. In addition, connecting tube 12 ₁
Of or prevent the the sample gas vaporized when the 10cm below adsorbed condensed in the connection tube 12 ₁ length, or disturbed flow of the sample gas can be prevented from being diluted.

Furthermore, the cuvette 1 and the plasma plurality between the torch unit, for example, three connection tube 12 ₁ to 12 ₃ is provided in parallel, and their connecting tubes 12 ₁ to 12 ₃ of the connecting portion in the three-way switching valve 14a, 14b by providing, for example, if the connection tube 12 ₁ is contaminated by the adsorption or the like of the sample gas,
It is possible to flow the way switching valve 14a, by operating 14b other connecting tube 12 ₂ or 12 ₃ to switched sample gas, removal of the conventional type of connection members, cleaning, connection and adjustment is not required, The analysis operation can be performed simply and continuously without interruption.

As described above, ultra-trace components in a sample in an inductively coupled plasma mass spectrometer can be analyzed with high sensitivity, high accuracy, and quickly.

In fact, by using the sample introduction device for inductively coupled plasma mass spectrometry of the present embodiment and conducting the following experiment,
It was confirmed that ultra-trace components in the sample could be analyzed with high accuracy.

Example 1-1 The electrodes 5a and 5b made of graphite, and 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 a sample injection hole of 2 mmφ in the center was formed into a cylindrical shape. 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. The electrodes 5a and 5b, the cuvette 1 and the cylindrical tube 3 were coated with a tantalum nitride film having a thickness of about 0.5 μm on the surface where the heated inert gas or the vaporized sample gas was in contact. Note that the coating of the tantalum nitride film was performed by applying an organic tantalum compound on a predetermined member surface and then firing in a nitrogen atmosphere. Furthermore, quartz pipe 9a and the plasma torch section of the heating furnace made of quartz glass connecting tube 12 ₁ (length 5 cm) between the (not shown) heated to about 200 ° C. In the infrared heater 13 _1.

Comparative Example 1-1 At room temperature (about 25 ° C.) without heating a quartz glass connecting tube.
° C) and the length of the tube was set to 5 cm, to thereby assemble the same sample introduction device as in Example 1-1.

Comparative Example 1-2 Connecting tube made of quartz glass at 200 ° C. with infrared heater
, And the same sample introduction device as in Example 1-1 was assembled except that the length of the tube was set to 20 cm.

Comparative Example 1-3 A connecting tube made of quartz glass was not heated, and was heated to room temperature (about 25
° C) and the length of the tube was set to 20 cm, and a sample introduction device similar to that in Example 1-1 was assembled.

Thus, Example 1-1 and Comparative Examples 1-1 and 1--1
10 µl of a 100 pg / ml uranium standard solution using a sample introduction device of 2, 1-3 and an inductively coupled plasma mass spectrometer
The ionic strength of 10 μl of a 0 pg / ml standard solution was measured under the following conditions.

Carrier gas in sample introduction device; 4.0 l / min argon.

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

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

Evaporation and evaporation in the 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 in plasma torch; 15 l / min.

Plasma gas in a plasma torch; 0.8 l / min.

As a result, in Example 1-1, the uranium standard solution 100 p
The ionic strength of the sample of g / ml was 490, and the ionic strength of the sample of 0 pg / ml of the same standard solution was 8. On the other hand, Comparative Example 1-
At 1, the ionic strength of the uranium standard solution 100 pg / ml sample is 7
4. The ionic strength of the sample of the same standard solution 0pg / ml is 7,
The uranium gas evaporated and vaporized because the connection tube was not heated was adsorbed to the connection tube, and the ionic strength of uranium was reduced. In Comparative Example 1-2, the uranium standard solution 10
The ionic strength of the sample of 0 pg / ml is 220, the ionic strength of the sample of 0 pg / ml of the same standard solution is 8, and the length of the connecting tube is 20.
The uranium gas vaporized and evaporated due to its long length was diluted, the flow was disturbed, or the uranium ion intensity was reduced by adsorption to the connecting tube. Furthermore, in Comparative Example 1-3, the ionic strength of the sample of 100 pg / ml of the uranium standard solution was 34, and the ionic strength of the sample of 0 pg / ml of the same standard solution was 5, indicating that the connecting tube was not heated and its length was The uranium gas evaporated and vaporized due to its long length of 20 cm was adsorbed on the connecting tube, diluted, or the flow was disturbed, and the ionic strength of uranium was greatly reduced.

Example 1-2 The electrodes 5a and 5b were made of graphite, and the 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 a central 2 mmφ sample injection hole having a cylindrical shape. 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.
One made of high-purity tungsten was used. The electrodes 5a and 5b, the cuvette 1 and the cylindrical tube 3 were coated with a tungsten nitride film having a thickness of about 0.5 μm on the surface where the heated inert gas or the vaporized sample gas was in contact. The coating of the tungsten nitride film was performed by applying an organic tungsten compound to the surface of a predetermined member, followed by firing in a nitrogen atmosphere. Further, a connecting tube 12 made of quartz glass between the quartz pipe 9a of the heating furnace and a plasma torch part (not shown).
₁ (length 5 cm) was heated to about 200 ° C. In the infrared heater 13 _1.

Comparative Example 1-4 A connecting tube made of quartz glass was not heated, and was heated to room temperature (about 25
° C) and the length of the tube was set to 5 cm, and a sample introduction device similar to that in Example 1-2 was assembled.

Comparative Example 1-5 Connecting tube made of quartz glass was heated to 200 ° C. with an infrared heater.
, And the same sample introduction device as in Example 1-2 was assembled except that the length of the tube was set to 20 cm.

Comparative Example 1-6 The connecting tube made of quartz glass was not heated, and was heated to room temperature (about 25
° C) and the length of the tube was set to 20 cm, and a sample introduction device similar to that in Example 1-2 was assembled.

Thus, Example 1-2 and Comparative Examples 1-4, 1-
5, 10-6 samples of thorium standard solution 100 pg / ml using the sample introduction device of 1-6 and the inductively coupled plasma mass spectrometer.
ashing conditions for 10 μl of the same standard solution 0 pg / ml
The ionic strength was measured under the same conditions as in Example 1-1 except that the temperature was set to 600 ° C. and 30 seconds. As a result, the present Example 1-2
Then, the ionic strength of the 100 pg / ml sample of thorium standard solution is 46
The ionic strength of the sample of 0 and the same standard solution of 0 pg / ml was 9. On the other hand, in Comparative Example 1-4, thorium standard solution 10
The ionic strength of the 0 pg / ml sample is 65, and the ionic strength of the standard solution 0 pg / ml sample is 10.Thorium gas evaporated and vaporized because the connecting tube is not heated is adsorbed on the connecting tube and the thorium ion Strength decreased. In Comparative Example 1-5, the ionic strength of the sample of 100 pg / ml of thorium standard solution was 210, and the ionic strength of the sample of 0 pg / ml of the same standard solution was 9, and the connecting tube was as long as 20 cm. The thorium gas was diluted, the flow was disturbed, or was adsorbed on the connecting tube, and the ionic strength of thorium was reduced. Further, in Comparative Example 1-6, the ionic strength of the sample of thorium standard solution 100 pg / ml was 31, and the standard solution was 0 pg / ml.
The sample has an ionic strength of 9, and the connecting tube is not heated and its length is as long as 20 cm, so thorium gas evaporated and vaporized may be adsorbed, diluted, or disturbed by the connecting tube. The ionic strength of thorium was greatly reduced.

As described above, in the sample introduction device of the first embodiment, the measurement of uranium and thorium is about 500 times as large as that of the ordinary inductively coupled plasma mass spectrometry, and is compared with the conventional inductively coupled plasma mass spectrometry using the conventional evaporative vaporization method. It is found that the detection sensitivity of uranium and thorium is improved about 10 times. In addition, the sample introduction device of the first embodiment can be used for an inductively coupled plasma emission spectrometer, and the detection sensitivity is further improved by about 10 times as compared with the conventional inductively coupled plasma emission spectrometry using the vaporization method. Can be achieved.

Example 2 The electrodes 5a and 5b were made of graphite, and the cuvette 1 was made of graphite having an outer diameter of 8 mm, an inner diameter of 6 mm, a length of 28 mm, and one sample injection hole of 2 mm in the center. No cylindrical tube was used, and the surfaces of the electrodes 5a and 5b and the cuvette 1 were not coated. Also, a quartz glass connecting tube 12 between the quartz pipe 9a of the heating furnace and the plasma torch part (not shown).
₁ (length 5 cm) was heated to about 200 ° C. In the infrared heater 13 _1.

Comparative Example 2-1 A quartz tube was heated at room temperature (about 25
° C) and the length of the tube was 5 cm, and a sample introduction device similar to that of Example 2 was assembled.

Comparative Example 2-2 Connecting tube made of quartz glass at 200 ° C. with infrared heater
Then, a sample introduction device similar to that of Example 2 was assembled except that the length of the tube was set to 20 cm.

Comparative Example 2-3 A connecting tube made of quartz glass was not heated and was heated to room temperature (about 25
° C) and the length of the tube was set to 20 cm, and a sample introduction device similar to that of Example 2 was assembled.

Thus, Example 2 and Comparative Examples 2-1, 2-2, 2
10 μl sample of 100 pg / ml aluminum standard solution using the sample introduction device and the inductively coupled plasma mass spectrometer of -3
Example 1 for 10 μl of a 0 pg / ml sample of the same standard solution
The ionic strength was measured under the same conditions as in Example 1. As a result, in Example 2, the ionic strength of the sample of 100 pg / ml of the aluminum standard solution was 380, and the ionic strength of the sample of 0 pg / ml of the same standard solution was 2. On the other hand, in Comparative Example 2-1, the ionic strength of the sample of 100 pg / ml of the aluminum standard solution was 87, and the ionic strength of the sample of 0 pg / ml of the same standard solution was 2, and the connection tube was not heated, so that the sample was evaporated and vaporized. The oxidized aluminum gas was adsorbed on the connecting tube, and the ionic strength of aluminum was reduced. In Comparative Example 2-2, the ionic strength of a sample of 100 pg / ml of the aluminum standard solution was 190,
The ionic strength of the pg / ml sample is 2, and the length of the connecting tube is as long as 20 cm, so that the vaporized aluminum gas is diluted, the flow is disturbed, or the ionic strength of the aluminum is absorbed by the connecting tube. Diminished. Furthermore, in Comparative Example 2-3, the ionic strength of the sample of 100 pg / ml of the aluminum standard solution was 39, and the ionic strength of the sample of 0 pg / ml of the same standard solution was 2, indicating that the connecting tube was not heated and its length was Due to the long length of 20 cm, the vaporized aluminum gas was adsorbed on the connecting tube, diluted, or the flow was disturbed, and the ionic strength of aluminum was greatly reduced.

As described above, in the sample introduction device of the second embodiment, the measurement of aluminum is about 500 times that of the ordinary inductively coupled plasma mass spectrometry, and is about 10 times that of the conventional inductively coupled plasma mass spectrometry using the conventional evaporative vaporization method. It can be seen that the detection sensitivity of aluminum is improved. In addition, the sample introduction device of Example 2 can be used for an inductively coupled plasma emission spectrometer, and has a detection sensitivity that is about 10 times higher than that of a conventional inductively coupled plasma emission spectrometry combined with an evaporative vaporization method. Improvement can be achieved.

[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 ultra-trace components in a sample with high sensitivity, high accuracy, and rapidity in an inductively coupled plasma mass spectrometer. is there.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a sample introduction device for inductively coupled plasma mass spectrometry showing one embodiment of the present invention. 1 ... cuvette, 2, 4 ... sample injection hole, 3 ... cylindrical tube, 5a, 5b ... electrode, 7a, 7b ... electrode block, 10a, 10b ... carrier gas external flow path, 11a, 11b ......
Carrier gas internal flow path, 12 _{1 to} 12 ₃ … Connection tube, 13
_{1 to} 13 ₃ ... infrared heater (heating means), 14a, 14b ... three-way switching valve (flow path switching member), 15 ... gas control mechanism,
20: Pressure switch, 24, 25: Solenoid valve, 26: Sample.

Claims (1)

(57) [Claims] 1. A heating furnace having an electrode made of an electric conductor and a cylindrical cuvette made of a heating substance having a sample injection hole in the center, and a cuvette passing from one end to the inside and the other end of the cuvette. A gas control mechanism for flowing an inert gas to a plasma torch part of the inductively coupled plasma mass spectrometer and controlling the flow of the inert gas; a connection member between the cuvette and the plasma torch part; Is formed of a transparent heat-resistant material, and the heating means is provided outside the connecting member so that a portion extending in a longitudinal direction of the connecting member is visible from the outside. Sample introduction device for analysis.