JPH09166544A - Atomic absorption spectrophotometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the intermittent flow of a discharged sample so as to stabilize a frame and thereby, to improve the accuracy of the analysis by applying machining for eliminating flow resistance to a sample discharge path in an atomizing chamber. SOLUTION: A sample jetted from a conical spray port 9 collides with a spherical collision body 10 so as to become fine perticles and to proceed entrained by gas flow in an atomizing chamber 12. The sample adhering to the internal wall of the atomizing chamber after atomization and becoming liquid drops again flows along the internal wall due to its own weight and is discharged from a drain 13 below. Machining for eliminating the flow resistance of a sample discharge path at this time is applied to prevent the turbulence of air flow caused by the discharged sample becoming stagnant and flowing down intermittently, and a frame F becomes stable to stabilize absorbance. That is, chamfering or the like is applied to the joint step difference 12a of constituent members of the atomizing chamber, an internal wall ridgeline part 12b of the atomizing chamber 12, an inlet ridgeline part 13a at the inlet of the drain 13, the pipeline joint step difference 13b of the drain 13, and the like. The discharged sample, thereby, flows smoothly to the drain along the internal wall of the atomizing chamber without pulsation, so that an accurate analysis ca be made.

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 a structure of an atomization chamber of an atomization section of a flame atomic absorption spectrophotometer.

[0002]

2. Description of the Related Art FIG. 3 shows the basic structure 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 atomization part 3, the target element contained in the atomized sample is dissociated by thermal energy and atomized, and a bright line of a specific wavelength in the light flux passing through the part is selectively and strongly absorbed. . 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.

FIG. 2 shows a conventional structure of the atomizing section 3 in the atomic absorption spectrophotometer constructed as described above. In order to analyze a liquid sample in a flame atomic absorption spectrophotometer, it is necessary to atomize the sample in the flame F of the burner. To improve the atomization efficiency, the liquid sample is atomized into fine particles. A chemical device M (nebulizer) is provided.

The sample solution introduced from the left side of FIG. 2 passes through the suction pipe 7 inserted in the atomizer M and reaches the inlet of the conical spray port 9 which is the tip end thereof. On the other hand, the auxiliary combustion gas (air) introduced into the atomizer M from the lower side of FIG. 2 advances to the right side of the drawing along the periphery of the suction pipe 7, and has an annular shape which is a gap between the atomizer M and the suction pipe 7. It is ejected from the auxiliary combustion gas outlet 8. At this time, the liquid sample is drawn out from the tip portion of the suction pipe 7 due to the negative pressure caused by the jet of the supporting gas, and is mixed with the jet flow of the supporting gas to be sprayed. Just before the conical spray port 9,
A spherical colliding body (impact ball) 10 made of glass is arranged in close proximity via a supporting arm 15 fixed to a fixing member 14 of the atomizer M, and the sample particles ejected from the conical spray port 9 have this spherical shape. It collides with the colliding body 10 and is further made into fine particles. The sample particles thus miniaturized are the annular fuel gas outlets 11 arranged around the atomizer M.
(A gap between the atomizer M and its fixing member 14) rides on the flow of fuel gas such as acetylene blown from the atomizer M, moves in the atomization chamber 12 in an L-shape, and atomizes well in the frame F of the burner. The absorbance is measured.

The adjusting screws 17 provided on the four sides of the suction pipe 7 are for adjusting the centering of the auxiliary combustion gas outlet 8 and the suction pipe 7.

[0007]

In the atomizing section 3 as described above, the sample is made into fine particles to increase the atomization efficiency, and at the same time, this is introduced into the stable frame F to obtain stable absorbance. Obtaining is important for analysis accuracy.

According to the structure of the atomization section 3 described above, the atomized sample adheres to the inner wall of the atomization chamber 12 and is re-dropped, and the sample is provided below the atomization chamber 12 through the wall surface by gravity. The collected drain 13 collects and discharges it (hereinafter referred to as discharged sample). At that time, the drain 13 in the atomization chamber 12 is discharged.
In the flow path of the discharged sample such as the inlet ridge line portion 13a, the joint pipe step portion 13b of the drain pipe, the ridge line portion 12b of the inner wall of the atomization chamber 12, and the joint step portion 12a between the vertical cylinder portion and the horizontal cylinder portion that configure the atomization chamber 12. Due to the flow resistance, the discharged sample temporarily stays and becomes droplets, and drops or flows out irregularly and intermittently in the atomization chamber 12. Therefore, the volume in the atomization chamber 12 is intermittently dropped by the droplets. The inventor of the present application found that the frame F causes a breathing phenomenon and fluctuates instantaneously, causing fluctuations in the absorbance. Then, based on such a novel finding, the present invention aims to provide an atomic absorption spectrophotometer capable of preventing the intermittent flow of the discharged sample and stabilizing the frame F to improve the analysis accuracy. I am trying.

[0009]

In order to achieve the above object, the atomic absorption spectrophotometer of the present invention is provided with an atomization chamber (including the chamber 12 and the drain pipe 13) of the atomization unit 3 after spraying. Processing for eliminating flow resistance of the sample discharge path when the sample adhered to the inner wall of the atomization chamber 12 and re-dropped is discharged along the inner wall by its own weight and discharged from the drain 13 provided below the atomization chamber 12. By performing the above, it is possible to prevent the turbulence of the air flow in the chamber due to the discharged sample staying and intermittently flowing down in the atomizing chamber, and to stabilize the frame to stabilize the absorbance.

The flow resistance means the discharged liquid represented by the seam step 12a of the constituent members of the atomization chamber 12, the ridge line portion 12b of the inner wall of the atomization chamber 12, the ridge line portion 13a of the drain inlet, the seam step 13b of the drain pipe, and the like. Refers to the part that forms the flow resistance.

In the atomic absorption spectrophotometer having the above-described structure, the discharged sample flowing down in the atomizing chamber 12 and discharged from the drain 13 is smoothly accumulated without temporarily accumulating the sample. Therefore, the breathing phenomenon of the frame F can be prevented and stabilized, and good absorbance can be maintained.

[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. 1 is an embodiment showing an atomizing section 3 of an atomic absorption spectrophotometer according to the present invention. Since the schematic configuration, sample introduction method, spraying principle, measurement method, etc. are the same as those of the conventional configuration shown in FIG. 2, the same reference numerals are given to the same members and their explanations are omitted.

In FIG. 1, the sample ejected from the conical spray port 9 collides with the spherical colliding body 10, is made into fine particles, and travels in the atomization chamber 12 along with the gas flow. The total amount of the injected sample is the discharged sample consisting of those that cannot be completely atomized and fall without riding the gas flow, or those that adhere to the inner wall of the atomization chamber 12 and become droplets again before reaching the frame F. 90 to 95% of. The discharged sample, which corresponds to most of the amount of the sample, is transmitted by its own weight along the inner wall surface and the like, and is collected and discharged in the drain 13 provided below the atomization chamber 12.

When the discharged sample flows down along the inner wall of the atomization chamber 12, for example, in FIG. 2 showing the conventional structure, the re-dropped liquid is re-dropped on the inner wall of the vertical cylinder portion forming the atomization chamber 12 is the vertical cylinder. Although it goes down along the inner wall of the part, it temporarily stays at the joint step 12a with the horizontal tubular part and drops as huge droplets, so that the air flow in the atomization chamber 12 is disturbed and the frame F is disturbed. Although it is considered to be unstable, FIG.
In the same portion 12a, since this step is eliminated as the same surface, the discharged sample reaching the lower end of the vertical tubular portion smoothly travels through the wall of the horizontal tubular portion toward the drain 13 in the depth direction of the paper.

Further, the discharged sample flowing down along the sprayer M side also stays at the ridge portion of the wall of the atomizing chamber such as 12b shown in FIG. 2 and pulsates by repeatedly enlarging and flowing out the droplets. However, in the configuration of the present invention shown in FIG. 1, this is solved by inclining the inner wall of the ridge.

In the conventional configuration shown in FIG. 2, since the inlet ridgeline (edge corner) 13a of the drain 13 has a corner, the discharged sample stays at this portion due to surface tension, and when it collects to a certain extent, it flows into the drain 13 at once. However, according to the configuration of the present invention shown in FIG. 1, since this portion is chamfered, the discharged sample smoothly flows to the drain 13.

Similarly, since the conventional drain pipe 13 as shown in FIG. 2 is simply connected to the pipe, the pulsating flow of the discharged fluid generated by the joint step 13b as a resistance also has a high analysis accuracy. Although it has been the cause of the decrease, the structure of the present invention shown in FIG. 1 eliminates the step in this portion and eliminates all the influence on the inside of the atomization chamber 12.

The part to which the present invention is applied is not limited to the above-mentioned part, but it is applicable to all parts other than this, which have a flow resistance of the discharged fluid and generate a pulsating flow.

Further, in order to improve the flowability of the discharged sample on the inner wall of the atomizing chamber 12, it is desirable that the atomizing chamber 12 is formed of a material having good water repellency such as stainless steel or fluororesin. Alternatively, it is desirable that the inner wall be roughened with abrasive paper or the like in the vertical direction in the figure to improve the flowability toward the drain 13. By improving the wettability of the portion where the discharged sample is likely to stay or the inner wall of the atomization chamber 12 with a fluororesin surface treatment agent or the like,
The formation of water droplets may be suppressed so that the water film can flow smoothly.

Further, in the structure of the conventional spherical colliding body 10 and the supporting arm 15 shown in FIG. 2, the discharged sample propagating through the supporting arm 15 becomes a droplet and directly drops to the drain 13, but this also causes the air flow in the room to be reduced. It is desirable that the configuration of the supporting arm 15 without dropping shown in FIG.

[0022]

According to the atomic absorption spectrophotometer of the present invention, the discharged sample flowing through the inner wall of the atomization chamber 12 of the sample atomization unit 3 to the drain 13 is based on the new finding for the cause of lowering the absorbance. Because it is a configuration that eliminates the factors that constitute the flow resistance so that it flows smoothly without pulsing,
Intermittent flow of discharged sample is prevented, frame F is stable,
Stable absorbance was maintained and accurate analysis became possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing an atomization part of an atomic absorption spectrophotometer according to the present invention.

FIG. 2 is a diagram showing an atomization section of a conventional atomic absorption spectrophotometer.

FIG. 3 is a diagram illustrating the basic configuration of a conventional atomic absorption spectrophotometer.

[Explanation of symbols]

 M ‥‥‥‥‥‥‥‥‥‥ Atomizer F ‥‥‥‥‥‥‥‥‥‥ Frame 1 ‥‥‥‥‥‥‥‥‥ Light source 2 ‥‥‥‥‥‥‥‥‥ System 3 ‥‥‥‥‥‥‥‥‥ Atomization unit 4 ‥‥‥‥‥‥‥‥‥ Spectrometer 5 ‥‥‥‥‥‥‥‥‥‥ Detector 6 ‥‥‥‥‥‥‥‥‥‥ Part 7 ‥‥‥‥‥‥‥‥‥‥ Suction tube 8 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ Sphere impactor 11 ‥‥‥‥‥‥‥‥ Fuel gas outlet 12 ‥‥‥‥‥‥‥‥‥ Atomization chamber 13 ‥‥‥‥‥‥‥‥‥ Drain 14 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥ ‥‥ Fixing member 15 ‥‥‥‥‥‥‥‥‥ Support arm 16 ‥‥‥‥‥‥‥‥‥ Air guide 17 ‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥‥

Claims (4)

[Claims] 1. A liquid sample introduced into an atomizer is ejected into an atomization chamber and atomized in the state of being atomized into fine mist particles, and a specific wavelength of a specific wavelength determined by the element is determined in this frame. A device for passing light and performing elemental analysis based on its absorbance, wherein the sample ejected into the atomization chamber adheres to the atomization chamber inner wall and is re-dropped, and this is propagated along the inner wall due to its own weight to the spray chamber. In a device configured to be discharged from a drain provided below, a sample discharge path in the atomization chamber is processed to eliminate flow resistance, and discharged sample stays and intermittently flows down in the atomization chamber. Atomic absorption spectrophotometer, characterized in that turbulence of the air flow in the room due to is prevented and the frame is stabilized to stabilize the absorbance. 2. The atomic absorption spectrophotometer according to claim 1, wherein a chamfering process is applied to a drain inlet ridge line portion which is a flow resistance of a sample discharge path in the atomization chamber. Total. 3. The atomic absorption spectrophotometer according to claim 1, wherein a process for eliminating a seam step in the drain pipe which is a flow resistance of the sample discharge path in the atomization chamber is performed. Photometer. 4. The atomic absorption spectrophotometer according to claim 1, wherein the step difference between the vertical tube portion and the horizontal tube portion forming the atomization chamber, which is the flow resistance of the sample discharge path in the atomization chamber, is eliminated. Atomic absorption spectrophotometer characterized by being processed.