JPH0996593A - Atomic absorption spectrophotometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the centering between the sample suction tube of an atomizer and a combustion improver gas blow-out port. SOLUTION: A sleeve-like member 20 for supporting a sample suction tube is disposed in a passage continuous to the atomization port in atomizer body M so that the boss part thereof can be fitted freely to the inner wall of passage. A sample suction tube 7 is inserted into a hole made in the member 20 for supporting the sample suction tube which is then set so that the boss part thereof is fitted tightly to the inner wall of passage within the atomizer body M thus centering the outlet end part of sample suction tube 7 and a combustion improver gas blow-out port 8. The atomizer can be assembled and adjusted without requiring any skill and the labor for readjustment can be saved significantly after finishing the assembly. Furthermore, good constitution can be sustained constantly during use and the absorbance can be measured stably under constant conditions of atomization thus realizing a high atomization efficiency and highly accurate analysis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomic absorption spectrophotometer, and more particularly to the structure of a sample atomizer for a flame atomic absorption spectrophotometer.

[0002]

2. Description of the Related Art In order to analyze a liquid sample in a flame atomic absorption spectrophotometer, it is necessary to atomize the liquid sample in the flame of a burner. An atomizer (nebulizer) for making particles is provided.

The structure of an atomizer in a conventional flame atomic absorption spectrophotometer is shown in FIG. In the conventional atomizer, an annular blowing port 8 is provided around the exit end of the suction tube 7 in which the tip is inserted into the liquid sample in the container, and an auxiliary combustion gas such as air is blown from the blowing port 8. Then, the outlet end of the suction pipe is set to a negative pressure, the sample solution is sucked from the suction pipe 7 and sprayed from the outlet end, and the fuel gas outlet 11 (atomization) provided around the auxiliary gas outlet 8 is further provided. Fuel gas such as acetylene is injected from a gap between the main body M and the fixing member 14 thereof, and the atomized sample is mixed with the supporting gas and the fuel gas in the atomization chamber 12 and placed on the flow of the fuel gas. , Into the flame that is burned by the burner.

The atomized sample particles are atomized by the frame of the burner after the atomization chamber 12 and the absorbance thereof is measured by the measuring light of a specific wavelength. To improve the analysis accuracy, atomization efficiency of the atomized sample particles should be increased. Is desired, that is, further refinement of atomized sample particles is desired. For this reason,
In the conventional atomizer, a spherical spherical collision body (impact ball) 10 made of glass fixed to the fixing member 14 of the atomizer body M via the support arm 15 is provided immediately before the conical spray port 9. That is, the sample particles ejected from the conical spray port 9 are made to collide with the spherical colliding body 10 to be further made into fine particles.

[0005]

In the atomizer as described above, it is important that the sample particles are efficiently and uniformly atomized, and therefore the conical spray port 9 is directed toward the spherical colliding body 10. So that the sample particles are uniformly ejected, the auxiliary combustion gas is blown out evenly around the outlet end of the sample suction tube 7 to spray the sample particles toward the spherical colliding body 10 as accurately and radially as possible. That is, it is important for atomization efficiency to accurately position the outlet end of the suction pipe 7 at the exact center of the auxiliary gas outlet 8 (spray port).

However, since the suction pipe 7 is supported only at two points, that is, the inlet of the atomizer body M and the air guide 16 near the spray port, the outlet end of the suction pipe 7 is not necessarily the true end of the auxiliary gas outlet 8. It was not accurately located in the center, and it was necessary to make adjustments with the fine adjustment screws 17. A detailed enlarged view of the vicinity of the adjusting screw 17 is shown in FIG. In the figure, the arrows indicate the flow of air, which is the auxiliary combustion gas. The air guide 16 fixed to the suction pipe 7 is adjusted from four sides (every 90 degrees) by adjusting screws 17.
Has been fixed by. In order to position the outlet end of the suction pipe 7 at the true center of the spray port, the centering is performed by manually operating the four adjusting screws 17 while visually recognizing it from the conical spray port 9 side. The adjustment work by the adjusting screw 17 is to perform a visual adjustment of the suction pipe 7 which is an ultrafine pipe at the center of the auxiliary gas outlet 8 which is a fine hole having a diameter of about 1 mm, and it is a precision work. In addition to requiring skill and time and effort, the efficiency of atomization, and hence the accuracy of analysis, changed significantly due to the poor quality of this adjustment.

Further, the support state is not stable at all, and a slight deviation may occur after adjustment due to vibration and other influences, and the spraying condition, that is, atomization efficiency due to this, is not constant, Inconveniences such as a decrease in detection sensitivity and variations / fluctuations in analysis results may occur.

Further, after the above-mentioned adjustment is carried out in the state of the atomizer main body M alone, it is incorporated into the fixing member 14, but when the adjustment is required again after the assembling, the adjusting screw 17 is provided inside the fixing member 14. I had to disassemble it again and readjust it.

The present invention makes the atomization state of the sample solution uniform by realizing accurate and stable positioning of the suction tube 7 in the atomizer, and makes it finer to increase the atomization efficiency of the sample and improve the analysis accuracy. It is an object of the present invention to provide an atomic absorption spectrophotometer capable of improving the above.

[0010]

In order to achieve the above object, in the atom absorption spectrophotometer of the present invention, in the atomizer, in the passage communicating with the spray port in the atomizer body,
A sleeve-shaped sample suction tube support member having a hole into which the sample suction tube is inserted and having a boss portion that fits freely into the inner wall of the passage in the atomizer body, the boss portion being provided on the inner wall of the passage. It is characterized in that the outlet end of the sample suction tube is centered at the center of the spray port by being fitted so as to be closely fitted.

In the atomic absorption spectrophotometer configured as described above, the sample ejecting gas (supporting gas) is evenly blown out from the periphery of the sample suction tube due to the structure of the atomizer, so that the sample is accurately radiated. The particles are ejected onto the surface and are uniformly and efficiently miniaturized by the spherical colliding body. Further, the adjustment and assembly of the atomizer does not require the skill or labor of the operator, and a good configuration is always maintained during use.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the atomic absorption spectrophotometer of the present invention will be described below with reference to the drawings.

FIG. 3 shows the basic construction of an atomic absorption spectrophotometer. In the figure, the light source unit 1 radiates a bright line spectrum including the resonance line of the target element, and these are passed through the atomization unit 3 (frame) by the optical system 2 and introduced into the spectroscope 4. These emission lines include light that does not undergo atomic absorption by the target element or light with a low absorption ratio, and these are excluded by the spectroscope 4 and the absorption line with the highest absorption sensitivity (in many cases, Is a resonance line) and is converted into an electric signal by the detector 5.

In the atomizing section 3, the target element contained in the atomized sample is dissociated by thermal energy and atomized, and a bright line of a specific wavelength is selectively and strongly absorbed in the light flux passing through the atomized section. . In the signal processing unit 6, the detector 5
Of the signals generated in step 1, only the signal proportional to the intensity of the bright line of the specific wavelength is extracted, logarithmically converted, and the value proportional to the absorbance or the value converted to the concentration is obtained and displayed on the CRT (not shown) or Printer / Plotter (not shown)
Record by.

In the atomic absorption spectrophotometer as described above, the present invention is characterized by the structure of the atomization unit 3, particularly the atomizer shown in FIG. The structure of the atomizer is roughly the same as in FIG.
5 and a fixing member 14 for supporting and fixing the atomizer main body. The remarkable point of the present invention is the configuration of the peripheral portion of the atomizer main body M, and other configurations are the same as the conventional configuration shown in FIG. 2. Therefore, only the peripheral portion of the atomizer main body M is detailed in FIG. Write down.

In FIG. 1, the atomizer is a suction tube which blows out an auxiliary combustion gas such as air around the outlet end of the suction tube 7 whose tip is inserted into a sample solution in a container (not shown). An annular auxiliary gas outlet 8 for generating a negative pressure is provided at the outlet of 7 to form a spray port. Since the sample solution is in constant contact with the suction tube 7 at a high concentration, it is desirable to form the suction tube 7 with a material having excellent corrosion resistance such as platinum iridium.

As shown in FIG. 4, the suction tube 7 is inserted into the center of the suction tube support member 20 in advance in a small hole having the same size as the suction tube, leaving an end portion, and an adhesive or the like is used. It is fixed by. Further, the suction pipe support member 20 is provided with an air hole 21 so that an auxiliary combustion gas such as air can flow (see FIG. 5, which is a sectional view taken along the line AA ′ of FIG. 1). Air hole 2
Although there is no particular limitation on the arrangement or size of the suction tube 1, it is preferable that the suction tube 7 is evenly arranged around the suction tube 7. Further, the outer diameter of the suction pipe support member 20 is designed with no margin in accordance with the inner diameter of the fixing member 14 of the atomizer body. Actually, the outer diameter of the suction pipe support member 20 is, for example, about 4 mm. The suction tube 7 set in this way is inserted into the atomizer body M made of fluororesin under the airtight condition through the O-ring 19, and the cap 18 is covered.

In order to achieve uniform and efficient atomization, it is important to place the tip of the suction pipe 7 exactly in the center of the auxiliary gas outlet 9, but according to the above-mentioned configuration of the present invention. For example, when the suction tube 7 is inserted into the suction tube supporting member 20, it is already fixed to the true central portion thereof, and when the suction tube supporting member 20 is inserted into the fixing member 14, it is accurately located in the true central portion of its inner hole. Fixed. Therefore, conventionally, it was necessary to provide an adjusting screw to perform centering adjustment, but as described above, by simply inserting and fixing each member and assembling, the tip end portion of the suction pipe 7 will have the auxiliary combustion gas outlet port. It can be easily and accurately located at the exact center of 9.

In this way, the tip portion of the suction pipe 7 is accurately centered and penetrates to the inlet of the conical spray port 9 as shown in FIG. On the other hand, the air (auxiliary combustion gas) introduced into the atomizer body M from the lower side of FIG. 1 is an air hole 21 provided in the suction pipe support member 20 (a sectional view taken along the line AA ′ in FIG. 1).
(See reference) and go to the right in the figure, and the atomizer body M and the suction pipe 7
It is ejected from the auxiliary combustion gas (air) blowout port 9 which is a gap between and (see FIG. 6 which is a cross-sectional view taken along the line BB of FIG. 1). At this time, the negative pressure caused by the jet of air causes the liquid sample to be drawn out from the tip of the suction pipe 7 and mixed into the jet of air to be sprayed.

[0020] For example, a cone angle of 20 ° is continuous with this spray port.
A conical spray port 9 having an opening of about 5 mm is provided. A support arm 15 detachably fitted to the conical spray port 9
Is fixed, and its tip is formed to have the same curvature as the spherical collision body. A spherical collision body 10 made of a material having excellent wear resistance and corrosion resistance, such as ceramics, is fitted to the tip end of the support arm 15, and the support arm 15 is made of synthetic resin, so that the spherical collision body 10 is supported by its elastic force. Holds. The distance between the conical spray port 9 and the spherical colliding body 10 integrated via the support arm 15 in this manner is designed to be the distance at which atomization of the spray sample particles is best performed. The inner diameter of the conical spray port 9 is generally about 5 mm, while the spherical colliding body 10 is generally about 6 mm-10 mm in diameter. In many cases, this distance is around 0. Has the highest atomization efficiency, that is, all of the atomized sample particles are spherical colliders 1.
It collides with 0 and is miniaturized. Since both members are integrally formed by the support arm 15, the distance relationship does not change due to assembly or the like, and the best distance relationship is always maintained.

The sample particles thus miniaturized ride on the flow of the fuel gas such as acetylene blown out from the annular fuel gas outlet 11 arranged around the atomizer body M and the atomization chamber. Efficiently sprayed into 12 and well atomized in the burner flame and its absorbance is measured.

[0022]

EXAMPLE In the above-mentioned structure, it is desirable to perform a surface treatment for improving wettability on the inside and outside of the spherical collision body 10, the support arm 15, or the conical spray port 9. This can be realized, for example, by using a commercially available chemical treating agent depending on the material. Even if the sprayed sample particles adhere to these members, they do not re-drop, but adhere to a film due to high wettability, and are blown off again as fine particles by the jet flow of the combustion-enhancing gas or fuel gas and then dropped. As a result, there is no adverse effect on the measurement part due to dropping and the utilization efficiency of the analytical sample is improved.

Further, in the above-mentioned configuration, the shape of the support arm 15 for holding the spherical collision body 10 is two arms, but there is no particular limitation on the number of arms and it may be circular. The contact surface of the support arm 4 with the spherical collision body 10 does not have to have a curvature, and convex dimples or concave dimples may be provided on both surfaces for attachment. Alternatively, the gripping force may be fixed by applying an adhesive to the contact surface regardless of the elastic force of the support arm 15.

[0024]

In the atomic absorption spectrophotometer according to the present invention, since the atomizer is provided with the supporting member on the sample suction tube and the suction tube is positionally fixed at the center of the supporting gas outlet, Sample jet gas (aiding gas) evenly from around the suction tube
Are spouted, the sample is spouted in a precise radial pattern, and the spherical colliding body uniformly and efficiently miniaturizes the sample. Further, since each member can be simply and accurately positioned by inserting and fixing each member, and at the same time, the tip end of the suction pipe 7 can be accurately and exactly located in the center of the auxiliary gas outlet 8, so that the assembly and adjustment of the atomizer can be performed. It does not require the skill level of the operator, and the labor of adjustment and readjustment after assembly can be greatly omitted. Furthermore, since a good structure can be maintained during use, stable atomization conditions and stable absorbance measurement can be achieved, and high atomization efficiency can be achieved for accurate analysis. It was

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a peripheral portion of an atomizer body of an atomic absorption spectrophotometer according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a conventional atomizer.

FIG. 3 is an explanatory diagram of a basic configuration of an atomic absorption spectrophotometer.

FIG. 4 is an enlarged explanatory view of a suction tube support member.

5 is a cross-sectional view taken along the line A-A ′ of FIG.

6 is a cross-sectional view taken along the line B-B ′ of FIG.

FIG. 7 is an explanatory diagram of a conventional centering adjustment method for an atomizer.

[Explanation of symbols]

 M ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Atomic part optical system 3 ‥‥‥‥‥‥‥‥‥‥‥‥‥ Atomization unit 4 ‥‥‥‥‥‥‥‥‥ Spectrometer 5 ‥‥‥‥‥‥‥‥‥ Detector 6 ‥‥‥‥‥‥‥‥‥ Signal processing unit 7 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥ ‥ Suction tube 8 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ ................ ‥‥‥‥ Fuel gas outlet 12 ‥‥‥‥‥‥‥‥‥ Atomizing chamber 13 ‥‥‥‥‥‥‥‥‥‥‥ Drain 14 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ ‥‥‥‥ Supporting arm 16 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ ‥ O-ring 20 ‥‥‥‥‥‥‥‥‥‥ Suction tube support member 21 ‥‥‥‥‥ ‥‥‥‥ air holes

Claims (1)

[Claims] 1. A liquid sample introduced into a main body of an atomizer through a sample suction tube is ejected from a spray port of the main body of the atomizer together with an auxiliary combustion gas to be atomized, and then sent into a combustion flame to be atomized. In this device, the sample suction tube is inserted into the passage connected to the spray port in the atomizer main body in an apparatus for performing elemental analysis based on the absorbance of light having a specific wavelength determined by the element in this frame. A sample suction tube supporting member in the form of a sleeve having a boss portion that fits into the inner wall of the passage in the atomizer body without freedom, so that the boss portion closely fits to the inner wall of the passage. Atomic absorption spectrophotometer, characterized in that the outlet end of the sample suction tube is centered at the center of the spray port by being attached to the.