JPS61219851A - Specimen spray apparatus for flame atom absorption analysis - Google Patents

Abstract

PURPOSE:To perform high sensitivity flame atom absorption analysis showing a high S/N ratio, in performing measurement, by spraying a specimen solution discharged from a sprayer in a mist form to a dispersing device having a reticulated structure to allow the same to pass through said dispersing device. CONSTITUTION:A concentric type sprayer 3, wherein a vacuum phenomenon generated by auxiliary fuel gas flowing as a high speed stream is applied, discharges a specimen solution 4 in a mixing chamber 7 for mixing fuel and the auxiliary fuel gas through a tube 5 in a conical mist state 6 non-uniform in a particle size. The mist is passed through a dispersing device 8 having a reticulated structure by discharge force to be dispersed and further formed into fine particles to be guided to a burner 10 along with the fuel and the auxiliary fuel gas as mist 9 having a unified particle size, and burnt and decomposed to form the atomic vapor of a metal element while light with a specific wavelength passing through the formed flame is absorbed. Large particles removed by a decomposition device 8 are discharged from a discharge port 11 as a waste solution. The gap between the decomposition device 8 and the sprayer 3 can be adjusted by a gap adjusting mechanism 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a sample atomization device for flame atomic absorption spectrometry. By spraying the sample solution released into the mixture with the sample solution and passing it through a disperser having a mesh mesh, it is possible to further atomize the mist and make the thickness of the mist uniform. Therefore, the amount of sample solution that reaches the flame is divided into four categories, and the thinner the mist that reaches the flame, the easier the thermal decomposition becomes. For these reasons, a disperser having a network structure can increase the density of the atomic vapor generated in the flame. This is particularly suitable for highly sensitive L7 beam atomic absorption spectroscopy.

In addition, the atomic absorption sensitivity can be arbitrarily reduced by simply changing the 1d gap between the atomizer and the disperser, which is particularly useful for reducing the dynamic range of atomic absorption spectrometry. Therefore, a flame atomic absorption spectrometer sample spraying apparatus is used, which is suitable even for measurements with reduced atomic absorption sensitivity in samples with a high degree of sensitivity, which is often required.

[Background of the invention]

As a method for atomizing the target element in a flame atomic absorption spectrophotometer, -i, the sample solution is aspirated by an atomizer and released in a mist state into a mixing chamber with fuel and auxiliary fuel gases, The method of guiding the material into the flame of a burner and burning it to thermally decompose it and generate atomic vapor of the target element is becoming popular. The atomic absorption sensitivity in this atomization device depends most greatly on the state of the mist of the sample solution discharged from the nebulizer, especially on the size of the particles of the mist. If the emitted mist particles are too large, they will adhere to the inner wall surface before mixing with the fuel and auxiliary fuel gas, and the amount of sample solution reaching the flame will be reduced, resulting in extremely low sample efficiency. Furthermore, in the flame, if the particles are too large, the thermal decomposition efficiency will decrease and noise will increase. For this reason, the atomic absorption sensitivity and the ratio of atomic absorption sensitivity to noise, that is, S/N, are extremely low compared to the amount of sample liquid sucked and discharged by the atomizer, since the generation of atomic vapor in 7 frames is low. descend. Therefore, in order to obtain high atomic absorption sensitivity in a flame atomic absorption spectrophotometer, it is necessary to introduce the sample solution into the 7V-memory in the form of a mist of as fine particles as possible.

However, the state of the mist emitted by the nebulizer commonly used in flame atomic absorption spectrophotometers is
There is very little mist of very fine particles of 2 to 10 microns or less, which is considered ideal because the particle size is non-uniform and it is easy to reach the flame, and the thermal decomposition efficiency is high. Most of them are large particles that are unsuitable for measurement, resulting in poor thermal decomposition efficiency and sample efficiency.

Therefore, in the flame atomic absorption spectrophotometer, the sample solution mist particles emitted from the atomizer are further atomized in the mixing chamber with the fuel and auxiliary fuel gas, and the particle sizes are unified to form a 7-rem mixture. In order to improve the thermal decomposition efficiency and sample efficiency, and to obtain higher atomic absorption sensitivity, so-called dispersers have been studied, and various methods of dispersers have been implemented.

These dispersers have a variety of structures, including spherical ones and ones with a shape similar to a ship's propeller. However, in either case, the structure of the portion onto which the sample solution in the form of mist emitted from the atomizer is sprayed is a surface. This is a method of dispersing the mist through resonance caused by the force of the spray and turning it into fine particles. Thus, a mist of atomized sample solution is introduced into the frame, bypassing the disperser. The atomic absorption sensitivity when using these conventional dispersers is approximately twice as high as the atomic absorption sensitivity measured without it, and the noise is reduced, so it is important to improve the S/N. This is because the dispersion device is effective in atomizing the fog and facilitating the thermal decomposition of the sample in the flame to improve the production of atomic vapor.

However, in the case of a conventional disperser that disperses the mist and atomizes it by spraying the sample solution in the form of a mist onto the structure of the surface, the mist is sucked by the atomizer and mixed with the fuel and auxiliary fuel gas in the form of a mist. Of the amount of sample solution released into the chamber, the amount that is further atomized and reaches the frame is only about 5. Most of it is discarded as waste liquid and is not used for measurements.

For these reasons, the conventional sample spraying apparatus for flame atomic absorption spectrometry has the disadvantage of poor sample efficiency, which is one of the two factors that dominate atomic absorption sensitivity, thermal decomposition efficiency and sample efficiency.

The sample solution mist emitted from the nebulizer also forms a cone shape. For this reason, if the gap between the sprayer and the disperser is made large, the area of the mist sprayed onto the disperser will increase and the force of the spray will decrease. In the case of conventional sample spray equipment for flame atomic absorption spectrometry, which uses the force of spraying the spray onto the structural parts of the surface to atomize the mist, it is necessary to use a sprayer and disperser that have high mist dispersion efficiency and can achieve the most atomization. The gap position is inevitably determined. For this reason, a fixed method is used. It is difficult to reduce the atomic absorption sensitivity by changing the gap between the atomizer and disperser. Therefore, a method of adjusting the amount of spray from a nebulizer has become common as a function of reducing the atomic absorption sensitivity used to measure a sample containing a particularly high concentration of a target element.

This atomic absorption sensitivity reduction function is required due to the narrow dynamic range of atomic absorption spectrophotometers, and is required relatively frequently.

-However, it is a concentric method in which the sample solution is sucked in and sprayed by applying the reduced pressure phenomenon caused by a flame atomic absorption spectrophotometer (used in a flame atomic absorption spectrophotometer). To adjust the amount of spray with this sprayer, it is necessary to adjust the amount of sample solution sucked by changing the flow rate of the auxiliary fuel gas.

Naturally, when the flow rate of the auxiliary fuel gas changes, the combustion state of the flame also changes. For this reason, it also has the disadvantage that it is necessary to adjust the flow rate of the fuel gas each time the atomic absorption sensitivity is adjusted to adjust the combustion state of the flame to be suitable for atomization of the target element.

[Purpose of the invention]

An object of the present invention is to use a disperser having a mesh structure as a disperser for spraying the sample solution sucked by the atomizer and released in the form of mist to make the mist into finer particles. It was installed in a mixing room with It improves the efficiency of released materials in a fog state and the efficiency of thermal decomposition in a flame, increasing S/N and enabling highly sensitive flame atomic absorption spectrometry.

Furthermore, since the mesh-structured disperser allows the mist to pass through, the atomic absorption sensitivity can be lowered with a relatively gentle slope by changing the gap between the atomizer and the disperser. Therefore, it is an object of the present invention to provide a sample spraying device for flame atomic absorption analysis in which the atomic absorption sensitivity can be arbitrarily reduced without changing the combustion state of the flame.

[Summary of the invention]

It was experimentally confirmed that the following phenomenon occurred when a sample solution in the form of mist discharged from a sprayer was sprayed through a mesh-structured disperser and measured.

a) Atomic absorption sensitivity is improved compared to when no disperser is used. Therefore, the network structure allows the mist to become fine particles.

) Atomic absorption sensitivity depends on the mesh size.

(3) Atomic absorption sensitivity depends on the gap between the atomizer and disperser. Atomic absorption sensitivity varies relatively slowly depending on the gap.

(4) Noise is reduced.

(5) Sample efficiency is improved.

These results show that the network-structured disperser is effective as a mechanism for improving the atomic absorption sensitivity and S/H and for changing the atomic absorption sensitivity.

FIG. 1 shows an example of the relationship between mesh size and atomic absorption sensitivity. A fine stainless steel net with approximately 30,000 meshes was used.

The size of the mesh is adjusted by overlapping the meshes. From the relationship M1 between the number of overlapping meshes and the atomic absorption sensitivity, it can be seen that the atomic absorption sensitivity depends on the size of the mesh. Approximately 3000
When the mesh size is the same as that of two 0-mesh meshes stacked on top of each other, the mist particles are finely divided, and the size of the mist can be unified, resulting in high sample efficiency and thermal decomposition efficiency, resulting in high atomic absorption sensitivity. Obtainable. The sample efficiency in this case is
This is an improvement of 3 to 5 times compared to conventional fog dispersion technology.

If the mesh is made too large, the ability to atomize the mist particles will decrease, making it impossible to standardize the size of the mist. For this reason,
Atomic absorption sensitivity does not improve much because sample efficiency and thermal decomposition efficiency decrease. There is also little reduction in noise.

If the mesh is too small, the mist will become fine particles,
Thermal decomposition efficiency increases and noise is reduced.

However, if the amount of sample solution that passes through the mesh and reaches the frame is small, the sample efficiency decreases and the atomic absorption sensitivity does not improve much.

FIG. 2 shows an example of the relationship between the gap between the atomizer and the network-structured disperser and the atomic absorption sensitivity. The size of the mesh is approximately 30,000 meshes made of two overlapping stainless steel meshes.

From the relationship line 2 between the gap and the atomic absorption sensitivity, it can be seen that the atomic absorption sensitivity depends on the gap. Due to the network structure, the sample solution in a mist state is further atomized by passing through a fine mesh, which is different from conventional dispersion techniques. Therefore, compared to conventional dispersion techniques, the dispersion efficiency for forming fine particles does not depend much on the force of spraying the mist emitted from the atomizer.

Therefore, since the dispersion efficiency does not change rapidly depending on the gap, the atomic absorption sensitivity changes gradually.

This shows that the atomic absorption sensitivity can be arbitrarily reduced by simply changing the gap between the atomizer and the disperser.

[Embodiments of the invention]

FIG. 3 shows an embodiment of a sample spraying device for flame atomic absorption spectrometry using the network-structured disperser of the present invention.

A concetric type atomizer 3 that applies the depressurization phenomenon caused by auxiliary fuel gas flowing at a high flow rate, and a sample solution 4 is passed through a tube 5 into a cone-shaped mist state 6 with non-uniform particle sizes. into a mixing chamber 7 with fuel and auxiliary fuel gas. The mist is dispersed by passing through the network-structured disperser 8 due to the force of the discharge, and the n1 particles become even finer particles, becoming the mist 9 with a uniform size and being sent to the burner 10 together with the fuel and auxiliary fuel gas. The fuel is decomposed and the atomic vapor of the metal is produced. It then absorbs light of a specific wavelength that passes through the frame. The large particles removed by the disperser 8 are discarded as waste liquid through the outlet 11.

Note that the gap between the disperser 8 and the sprayer 3 is adjusted by a gap adjustment mechanism 12.
It can be changed arbitrarily by

Figure 4 shows that in the case of a sample spraying device equipped with a disperser that atomizes the mist by passing it through the mesh structure of the present invention (two stainless steel meshes of about 30,000 meshes), it is different from the conventional one. This is an example of a comparison of the atomic absorption spectra of a sample spraying device equipped with a disperser that sprays forcefully into a spherical shape to disperse particles into fine particles, and a sample spraying device that does not use a disperser. be.

Atomic absorption spectrum 13 from a sample spraying device that does not use a disperser shows that the sample solution is emitted in the form of a mist of large particles, so the amount of sample solution reaching the flame is extremely small, and the mist is not atomized. Therefore, the thermal decomposition efficiency in the flame is low, and the atomic absorption sensitivity is the lowest. There is also a lot of noise.

Atomic absorption spectra 14 using a sample atomizer equipped with a spherical disperser, which is a conventional dispersion technique, are as follows: Compared to the atomic absorption spectrum 13 without this, the atomic absorption sensitivity is improved by about twice and noise is also reduced.

The atomic absorption spectrum 15 of the sample spraying device equipped with the network-structured disperser according to the present invention can improve the sample efficiency by about 3 to 5 degrees compared to the conventional disperser, so the atomic absorption sensitivity can be further increased by 1.5 cm. Improved by about 5 times.

〔Effect of the invention〕

According to the present invention, in a flame atomic absorption spectrophotometer, it is possible to further atomize particles of a sample solution released in a mist state by an atomizer into a mixing chamber with fuel and auxiliary fuel gas, and to reduce the size of the particles. It can be homogenized and introduced into the frame.

Therefore, sample efficiency and thermal decomposition efficiency in the flame are improved, and a high S/N ratio can be obtained, which is effective in performing high-sensitivity flame atomic absorption spectrometry.

Furthermore, since the atomic absorption sensitivity can be lowered arbitrarily by changing the gap between the atomizer and the disperser, it is also effective in measuring high concentration samples.

[Brief explanation of drawings]

FIG. 1 is a relationship diagram showing an example of the relationship between the mesh size and atomic absorption sensitivity in the disperser of the present invention, and FIG. 2 is a relationship diagram showing an example of the relationship between the gap between the disperser and the atomizer of the present invention and atomic absorption sensitivity. FIG. 3 is a mechanical diagram showing an embodiment of the present invention, and FIG. 4 is a spectrum diagram explaining the effects of the embodiment. 1... Relationship line between the number of overlapping meshes and atomic absorption sensitivity, 2...
・Relationship line between the gap between the atomizer and the disperser and the atomic absorption sensitivity, 3
... Concentric sprayer, 4... Sample solution,
5... Sample solution suction tube, 6... Non-uniform sample solution mist of particles emitted from the atomizer, 7... Mixing chamber for atomized sample solution, fuel gas, and auxiliary fuel gas.
8...Mesh-structured disperser, 9...Atomization and particle size are unified by the disperser, mist of the sample solution introduced into the flame, lO...burner, 11...Drainage of waste liquid Outlet, 12... Distributor position, SI4I4 groove mechanism 3.
...Atomic absorption spectrum in a sample atomizer without a disperser, 14...Atomic absorption spectrum in a sample atomizer equipped with a conventional disperser, 15...Sample using the disperser of the present invention Atomic absorption spectrum in a spray device.

Claims (1)

[Claims] 1. The sample solution is made into a mist, mixed with fuel and auxiliary fuel gas, and introduced together into the burner flame to be burned and decomposed, and the atomic vapor of the metal element generated in the flame absorbs only light of a specific wavelength. Applying the property of reducing light by
In a flame atomic absorption spectrophotometer that determines the concentration of metal elements contained in a sample solution, a disperser with a mesh structure made of wire mesh, etc. installed in the mixing chamber of the sample, fuel, and auxiliary fuel gas is used to measure the concentration of metal elements contained in a sample solution. The sample solution that is sucked in and discharged in the form of a mist is sprayed and passed through a mesh to further atomize the particles and unify the size of the mist, and the use of a sprayer and a disperser. A sample spraying device for flame atomic absorption analysis, characterized in that the gap can be changed arbitrarily.