JPH0658870A - Atomic absorption/emission analyzer - Google Patents

Abstract

PURPOSE:To provide an atomic absorption/emission analyzer which prevents dust from entering and exhausts poisonous gas generated within the device. CONSTITUTION:A dust protective cover 35 is provided on the upper surface of a case 34 which houses an auto-sampler 5 and an atomizing device 1 combined with it. In addition, inactive clean gas is injected and blown to the entire surface of the atomizing device 1, and is exhausted outside by an exhaust tube 38 containing an air flow adjusting value 37 and a fan 36.

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, an optical emission analyzer and the like, and more particularly to an atomic absorption and emission analyzer in which the measuring environment of an apparatus having an autosampler is cleaned.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view of an atomizer 1 and an autosampler 5 in a conventional flameless atomic absorption spectrophotometer. The flameless atomic absorption spectrophotometer is widely used for analyzing trace elements in steel, petroleum, chemicals, foods, etc. at the ppb to ppt level. In addition, recently, it is also used for quality control of pure water and reagents used in the manufacturing process of semiconductors, for measurement of contaminated heavy metals in wafer cleaning water, and for measurement of heavy metals in blood and urine.

Further, in many cases, a flameless atomic absorption spectrophotometer is combined with an autosampler 5 in order to shorten the measuring time and improve the measuring accuracy. In FIG. 6, the sample is carried into the atomizer 1 on the right by the autosampler 5 on the left. Both sides of the cuvette 6 in the atomizer 1 are sandwiched between graphite electrodes 7 and 8 and metal electrodes 9 and 1, respectively.
Pressed into 0 and held. The metal electrodes 9 and 10 are fixed to the electrode supporting bases 11 and 12 by bolts 13 and 14, respectively, and the electrode supporting bases 11 and 12 are slidably mounted on two parallel sliding shafts 15 via bearings 19. Placed.

A member 17 having a purge gas filling port 16 is provided between the electrode support bases 11 and 12. The right end of the sliding shaft 15 is fixed by a bolt 18, and a spring 21 is provided between the stopper 20 and the bearing 19 to press the electrode support base 11 to the right. The pressure by the spring 21 is applied to.
A lid 22 having a handle 23 for shutting off air when the cuvette 6 is heated is provided on the cuvette 6.

The automatic sampler 5 includes a turntable 25.
The sample 41 from the predetermined sample cup 24 of the nozzle 27
The sample arm 31 is rotated and the sample arm 31 is rotated to supply a predetermined amount of the sample 41 into the cuvette 6 through the hole 32 of the lid 22 of the atomization device 1. The sample cup 24 on the turntable 25 is sequentially rotated by the rotary shaft 28 to deliver the sample to the lower part of the nozzle 27.

A sample cover 26 is placed on the turntable 25 to prevent dust from entering the sample cup 24. A power cable is connected to the electrode supporting bases 11 and 12, and the cuvette 6 is heated by a maximum current of 400 A to decompose and atomize the sample inside. If this heating is mistaken, the sample will be bumped and good reproducibility cannot be obtained. Further, the atomic vapor at the center of the cuvette 6 is irradiated with light from an atomic spectrum light source for atomic absorption analysis.

In the frameless analysis, the sample is dried,
Since heating is performed in the order of ashing and atomization, one sample usually requires a measurement time of 1 to 3 minutes. In addition, when a sample is manually inserted, it takes more time and the amount of the sample varies, so an auto sampler is usually used. Further, Japanese Utility Model Application Laid-Open No. 62-178353 discloses that the upper part of the flameless atomic absorption spectrometer is covered with a cover to discharge harmful gas generated when the cuvette is heated by an exhaust duct.

[0008]

Since the frameless analysis has high analysis sensitivity, there is a problem that it is easily affected by dust in the room, polluted gas in the air, and the like. In addition to liquids, rock, plastic, steel,
There are many solid substances such as plants and foods, and when solid substances are liquefied by using an acidic reagent such as nitric acid or hydrochloric acid or an organic solvent, smoke or harmful vapor during heating is generated in the cuvette 6.
It scatters around and rusts the surrounding parts and causes contamination, which deteriorates the analysis accuracy.

[0009] For example, if dust in the air enters the cuvette, or if the acidic vapor discharged from the cuvette 6 adheres to the surface of the cuvette, the accuracy of analysis of silicon, sodium, magnesium, etc. is greatly reduced. For this reason, an atomic absorption spectrophotometer was installed in advance in a clean room for the analysis of sodium, silicon, etc., but there were problems such as an increase in size and an increase in price.

In Japanese Utility Model Application Laid-Open No. 62-178353, the atomizer is provided with a cover to prevent dust in the room from being mixed in, and at the same time, to emit toxic gas when the cuvette is heated. The same consideration has not been given to the integrated frameless atomizer,
There are problems that the cover of the atomization device interferes with the operation of the autosampler, and that the purge gas does not flow to the autosampler. An object of the present invention is to use an atomic absorption spectrometer with an autosampler capable of performing analysis with high accuracy and reproducibility by preventing contamination by toxic gas from indoor air or cuvettes without using the clean room.
An object is to provide an optical emission analyzer.

[0011]

In order to solve the above-mentioned problems, a detachable cover is provided on the upper surface of the case that houses the autosampler and the atomizer. Further, the cover is made of a flame-retardant transparent plastic material. Further, an inert gas purging gas is supplied into the case and is exhausted to the outside by an exhaust means. Further, the purge gas is a clean one in which dust, foreign gas, etc. are removed in advance. Further, the exhaust means is an exhaust tube having a valve for adjusting the air flow and a fan. Further, the purge gas outlet is arranged near the atomization device.

[0012]

The above-mentioned cover prevents dust from intruding into the case housing the autosampler and the atomizer, and the cover made of the flame-retardant transparent plastic material is the operating state of the autosampler and the atomizer. Enables monitoring of.
Further, the purge gas exhausts the harmful gas emitted by the atomizer to the outside, and the purge gas is made clean to prevent dust, foreign gas, etc. from entering the case. To be done. Further, the valve and the fan for adjusting the air volume of the exhaust tube enable the exhaust speed to be adjusted. Further, by disposing the purge gas outlet in the vicinity of the atomization device, the flow velocity of the purge gas in the vicinity of the autosampler is slowed or stagnated to prevent sample evaporation.

[0013]

1 is an external view of a flameless atomic absorption spectrophotometer according to the present invention. In FIG. 1, solution sample atoms atomized by the atomization device 1 are irradiated with the emission line of the target element emitted from the hollow cathode lamp of the light source unit 2, and the absorption spectrum is detected by the light reception detection unit 3. Further, the gas control unit 4 controls the flow rate of the gas flowing into the atomic device 1, and the autosampler 5 automatically supplies a large number of samples to the cuvette in the atomic device 1 in a predetermined order.

FIG. 2 is a partial sectional view of the frameless atomic absorption spectrophotometer. The autosampler 5 and the atomizing device 1 exposed at the upper part of the case 34 are covered with a cover 35 without any gaps to shut off external air. It should be noted that it is desirable to use a transparent flame-retardant plastic material or the like for the cover 3 in order to confirm the safety by observing the heating state of the cuvette and the operating state of the auto sampler.

Further, a hose 39 is connected to a joint 40 on the front of the case 34 to inject a purge gas such as clean nitrogen or argon into the inside of the apparatus, and the exhaust tube 38 behind the case 34 exhausts the gas to the outside. . At this time, harmful gas generated by heating the cuvette 6 is also exhausted. It should be noted that the exhaust tube 38 has a fan 36 for exhaust and a valve 37 for adjusting the air flow so as to efficiently discharge the heat generated when the cuvette 6 is heated to the outside of the apparatus, so that the harmful gas can be analyzed accurately. It is possible to prevent adverse effects, corrosion of peripheral devices, and adverse effects on the human body.

Further, the purging gas from the hose 39 is branched into two by the joint 40 and passed through both sides of the upper surface of the autosampler 5 to be sent in front of the atomizer 1. As a result, the purge gas uniformly flows over the entire surface of the atomizer 1. Since the dustproof sample cover 26 is provided on the upper surface of the sample cup 24 of the autosampler 5, the sample cup 24 can be double dustproofed by the cover 35.

FIG. 3 is a top view of the flameless atomic absorption spectrophotometer shown in FIG. When the purge gas is rapidly flown to the peripheral portion of the solution sample in the sample cup 24, there arises a problem that the sample 41 is evaporated and its concentration is changed. Therefore, the purge gas outlet 42 is arranged behind the autosampler 5. As a result, the purge gas stagnates in the periphery of the autosampler, so that evaporation of the sample 41 is prevented, and
Toxic gas generated when the cuvette 6 is heated passes through the upper surface of the atomizer 1 and is trapped outside through the exhaust tube 38.

FIG. 5 shows sodium measurement data obtained by the apparatus of the present invention. FIG. 5 shows that the measurement of sodium at a low concentration of 0.2 ppb measures reproducibly. On the other hand, in the conventional device, the measured values greatly fluctuate as shown in FIG. 4, so that sodium could not be reliably measured at the 0.2 ppb level. The present invention is not limited to the flameless atomic absorption spectrophotometer described above, but is also a flame atomic absorption spectrophotometer, flame photoabsorptiometer, ICP (Inductive Coupled Plasm) that performs microanalysis in combination with an autosampler.
a) The same effect can be obtained by applying it to a light emission analyzer or the like.

[0019]

According to the present invention, since the dustproof cover is provided on the autosampler and the atomizer, it is possible to prevent the dust in the room from entering the inside of the sample cup or the cuvette and lowering the analysis accuracy. In particular, since the dust contains a large amount of silicon, sodium and the like, it is possible to improve the analysis sensitivity of silicon and sodium and the stability of measurement.

Further, since a clean gas of an inert gas is flown inside the cover and is exhausted to the outside of the room, it prevents the acid gas generated by the heating of the cuvette from rusting the parts inside the apparatus and protects the health of the measurer. can do. Furthermore, since it is not necessary to put the equipment in a clean room for semiconductor manufacturing equipment that uses acids and organic solvents,
The space of the clean room can be effectively used and the economical efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an external view of a flameless atomic absorption spectrophotometer according to the present invention.

FIG. 2 is a side view of a flameless atomic absorption spectrophotometer according to the present invention.

FIG. 3 is a top view of a flameless atomic absorption spectrophotometer according to the present invention.

FIG. 4 is an example of sodium analysis data by a conventional device.

FIG. 5 is an example of sodium analysis data by the device of the present invention.

FIG. 6 is a cross-sectional view of an atomizer and an autosampler.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Atomization device, 2 ... Light source part, 3 ... Light receiving detection part, 5 ... Autosampler, 6 ... Cuvette, 7, 8 ... Graphite battery, 9, 10 ... Metal electrode, 11, 12 ... Electrode support stand, 1
3, 14, 18 ... Bolt, 15 ... Sliding shaft, 16 ... Purge gas inlet, 17 ... Member, 19 ... Bearing, 20 ... Stopper, 21 ... Spring, 22 ... Lid, 23 ... Handle, 24 ... Sample cup, 25 ... turntable, 26 ... sample cover, 27 ... nozzle, 28 ... rotation axis, 29 ... arm, 3
0 ... Tube, 31 ... Sample arm, 32 ... Hole, 33
… Cuvette hole, 34… Case, 35… Cover, 36…
Fan, 37 ... Valve, 38 ... Exhaust tube, 39 ... Hose, 40 ... Joint, 41 ... Sample, 42 ... Gas outlet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Kagaya 2326 Imai, Ome-shi, Tokyo Hitachi, Ltd. Device Development Center

Claims (6)

[Claims] 1. An atomic absorption / emission analyzer comprising an autosampler for supplying a sample in a plurality of sample cups and an atomization device for atomizing the sample and measuring its absorption and emission characteristics. And an atomic absorption / emission analysis device, wherein a detachable cover is provided on the upper surface of the case that houses the atomization device. 2. The apparatus according to claim 1, further comprising means for supplying an inert gas purging gas and a means for exhausting the purging gas in a case containing the autosampler and the atomizer. Characteristic atomic absorption and emission analyzer. 3. An atomic absorption / emission analysis apparatus according to claim 2, wherein the exhaust means for the purging gas is an exhaust tube containing a valve for adjusting the air flow and a fan. 4. The atomic absorption / emission analysis device according to claim 2 or 3, wherein the outlet for the purging gas is provided in the vicinity of the atomization device. 5. The method according to any one of claims 1 to 4,
An atomic absorption / emission analysis device characterized in that the cover is made of a flame-retardant transparent plastic material. 6. The method according to any one of claims 1 to 5,
An atomic absorption / emission spectroscope characterized in that the purging gas is one in which dust, foreign gas, etc. have been removed in advance.