JP3217868B2 - Hydrogen sulfide analysis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to arsine relates hydrogen sulfide analysis method for analyzing the hydrogen sulfide in the sample gas, such as phosphine (H ₂ S) with high precision is a compound semiconductor material.

[0002]

2. Description of the Related Art Arsine and phosphine are prepared from metal organic vapor phase growth (Metal Organic Vapor Pha).
se Epitaxy; hereinafter, referred to as MOVPE) or a vapor phase epitaxy method (vapor phase epitaxy).
axy (hereinafter, referred to as VPE)) is mainly used as a group V source gas of a group III-V compound semiconductor. In the field of using these gases, it is extremely important to purify the raw material gas, and impurities mixed in the raw material affect the optical and electrical characteristics of the crystal and consequently function to degrade the device performance.

[0003] Conventionally, Al has been used as an impurity in the raw material gas.
The presence of oxygen and water has become a problem due to the demand for improving the performance of GaAs semiconductor lasers. Purification has been performed with a focus on these issues. As a result, silicon, sulfur, and germanium, which are N-type impurities, are increasingly recognized as problematic impurities, and there is a strong demand for gas purification and analysis assurance. The presence of an N-type impurity lowers the electron mobility of the crystal, causing HEMT noise. Furthermore, it has been reported that in the production of red GaAsP light emitting diodes by VPE, the luminance is greatly reduced due to the presence of sulfur impurities (Craven, RA; Fin).
n, DJAppl.Phys.50,6334-6343 (1979)). The crystal defects and impurities in the compound semiconductor, and the relationship between them and device defects, have not yet been sufficiently elucidated. When purifying the above-mentioned raw material gas, it is important to systematically purify and remove it after clarifying the target impurity and its problematic level. There is an urgent need to establish analytical techniques that can be confirmed.

[0004]

Among the above-mentioned compounds of the N-type impurities, a method for analyzing hydrogen sulfide (H ₂ S) is known as having a problem in the analysis technique. As a general method for analyzing hydrogen sulfide, in a method of analyzing hydrogen sulfide in a bulk gas such as nitrogen, a flame photometric gas chromatograph (FPD-G) is used.
C) method is used. Figure 12 (a), (b) An example of analysis of hydrogen sulfide by the FPD-GC _{method, (a) N 2 -H 2} S (8.4ppm) mixed gas,
(B) shows the results of analysis of the H2-PH3-H2S (0.8 ppm) mixed gas. In (a) of hydrogen sulfide in nitrogen, a sharp peak appears, whereas in (b) of hydrogen sulfide in phosphine, a tailing phenomenon of phosphine occurs, and peak measurement becomes difficult as the concentration becomes lower. . Furthermore, in the analysis of hydrogen sulfide in arsine, since the peaks of arsine and hydrogen sulfide overlap, it is very difficult to find satisfactory analysis conditions for hydrogen sulfide in these gases by gas chromatography and to analyze them with high sensitivity.

A method is known in which a general methylene blue absorptiometric method (colorimetric method) is applied to arsine and phosphine for analysis. After a sample is absorbed in an absorbing solution, a p-dimethylaniline solution is used. This method of adding hydrogen chloride and iron (III) solution and measuring the absorbance of the generated methylene blue to determine hydrogen sulfide is based on the sensitivity of a colorimeter based on Lambert-Beer's law and the amount of gas available for sampling. The lower detection limit was considered to be about 0.1 ppm, and it was impossible to detect a trace amount of hydrogen sulfide lower than that.

The present invention has been made in view of the above circumstances, and has as its object to provide a method for analyzing hydrogen sulfide (H ₂ S) in a sample gas such as arsine and phosphine with high accuracy. .

[0007]

According to the present invention, in order to solve the above-mentioned problems, a sample gas is brought into contact with an absorbing solution containing an antioxidant so that hydrogen sulfide in the sample gas is absorbed by the absorbing solution and captured. The absorption liquid that has collected hydrogen sulfide is then subjected to an inductively-coupled high-frequency plasma spectroscopic analyzer that measures the emission intensity by spectrally analyzing the emission line spectrum of sulfur generated when the element to be measured is excited by plasma. While measuring
A standard gas containing a known concentration of hydrogen sulfide was passed through the absorbing solution to absorb a predetermined concentration of hydrogen sulfide, and the solution was measured for emission intensity with an inductively coupled high-frequency plasma spectrometer to prepare a hydrogen sulfide calibration curve. The hydrogen sulfide concentration of the sample gas was measured from the calibration curve.

When the above-mentioned absorbing solution is introduced into a plasma torch of an inductively coupled high-frequency plasma spectrometer, the absorbing solution is mist-formed by an ultrasonic vibrator, and is supplied while heating with a carrier gas to supply a concentrated sample. Preferably, an ultrasonic nebulizer is used.

[0009]

The sample gas is brought into contact with an absorbing solution containing an antioxidant, and the hydrogen sulfide in the sample gas is absorbed by the absorbing solution and collected, thereby preventing oxidation when hydrogen sulfide is absorbed. ^{Collected in 2-} ion state. By performing inductively coupled high frequency plasma spectroscopy in the state of S ²⁻ ions,
Sulfur can be quantitatively analyzed with high accuracy. That is,
In this inductively-coupled high-frequency plasma spectroscopy, the analysis peaks in the analysis of arsine and phosphine do not overlap as in the conventional flame photometric gas chromatography (FPD-GC) method, and hydrogen sulfide in arsine and phosphine is removed. It can be measured with high sensitivity. Further, in the method of the present invention, an ultrasonic nebulizer is used to guide the absorbing solution to the plasma torch of the inductively-coupled high-frequency plasma spectrometer.
Measurements can be performed at detection limits that are orders of magnitude lower.

[0010]

EXAMPLES The method for analyzing hydrogen sulfide according to the present invention will be described in detail below. In the present invention, when analyzing hydrogen sulfide in a sample gas such as a source gas for compound semiconductors such as arsine and phosphine and various high-purity gases, it was generally said that high sensitivity could not be expected for the analysis of sulfur. Inductively coupled plasma (Inductively Coupled Plasma) is a basic analysis technique for metal analysis.
ma) Spectroscopic analysis (hereinafter abbreviated as ICP) was adopted as a method for detecting sulfur.

FIG. 1 shows the principle of ICP measurement. In FIG. 1, reference numeral 1 denotes a spectroscope, 2 denotes a photomultiplier, 3 denotes plasma,
4 is a plasma torch, 5 is a high frequency power supply, 6 is an automatic gas control mechanism, 7 is an argon gas source, 8 is a photometric system connected to the spectrometer 1, 9 is a computer for data processing, 1
Reference numeral 0 denotes a display for display, 11 denotes a printer, and 12 denotes a floppy disk. In this ICP, energy from a high-frequency power source is matched by a tuned coupler and efficiently supplied to a plasma torch 4 surrounded by an induction coil to generate a high-frequency magnetic field. When the argon stream passes through this magnetic field, it becomes ions and a high-temperature plasma 3 is formed from the tip of the torch 4. This plasma 3 has a donut-shaped hollow shape. The sample solution 13 is atomized by a nebulizer (not shown), and the atomized sample passes from the center of the torch 4 to the center of the donut-shaped plasma 3 by another argon stream. The measurement element in the atomized sample is excited by the high-temperature plasma 3 and emits a bright line spectrum as radiant energy. The emission spectrum of sulfur is around 180 nm. Light from the plasma 3 is split by the spectroscope 1, detected by the photomultiplier tube 2 circumscribing the exit slit 14, amplified by an amplifier, and processed by the computer 9. It depends on the element to be measured.
Level metal analysis is possible.

[0012] In the analysis of hydrogen sulfide, an absorption solution for absorbing and concentrating hydrogen sulfide was first studied. Of the four methods specified in JIS for the method of analyzing hydrogen sulfide in exhaust gas, three methods except gas chromatography absorb hydrogen sulfide in a strongly alkaline absorbent (edited by the Japan Standards Association)
Method for analyzing hydrogen sulfide in exhaust gas K0108 (1983)). Hydrogen sulfide is dissolved in 1 cm ³ of water at 1 atm.
Six times, 4.67 times the gas volume is dissolved at 0 ° C., showing very high solubility compared to other gases, and even higher solubility in alkaline liquid. Increasing the alkali concentration is not preferable because the characteristics of ICP, that is, the matrix (liquidity) of the sample solution are easily affected, and components other than the analysis target increase the background and particularly dislike strong alkalinity. Therefore, as a result of examining an alkaline solution having a concentration as low as possible while suppressing the influence of the background as much as possible, the absorption solution was 0.001 to 0.01% by weight.
Is preferred. When the KOH concentration is 0.0
If the content is less than 0.01% by weight, absorption of hydrogen sulfide cannot be sufficiently performed, and if the content exceeds 0.01% by weight, the influence of the matrix in the above-described analysis by ICP is exerted and the measurement accuracy is reduced.

In a sampling experiment using an N ₂ -H ₂ S mixed gas, it was found that the emission intensity of sulfur was large depending on its ionic structure. The details of the experiment will be described in detail.

(Experiment 1) FIG. 2 shows an experimental system diagram. In this experiment, the N ₂ -H ₂ S mixed gas 20 was used, and the mixed gas 20 was introduced into the absorbing solution 21 and bubbled to collect hydrogen sulfide. The absorption bottle 22 was made of a fluororesin, the absorption liquid amount was 150 ml, and the mixed gas flow rate was 1.0 liter / min. Nitrogen purge was performed before and after introducing hydrogen sulfide into the sampling line, and after sampling, analysis was performed by ICP (measurement wavelength 180.7 nm).

After sampling, the sulfur content in the absorbing solution is determined by IC
P was quantitatively analyzed. The calibration curve used was obtained by diluting sulfuric acid with ultrapure water. As a result, hydrogen sulfide is 100%
It repeatedly showed concentrations much higher than the sulfur concentration assumed to be absorbed. In the ICP analysis, a general method is to prepare a calibration curve using an aqueous solution of sulfuric acid. If the absorption efficiency of the sampling is poor, the value should be lower than the quantitative value, but here the opposite phenomenon occurred. This difference is considered to be due to the difference in the state of sulfur present in the sulfuric acid aqueous solution and the absorption solution. Therefore, a luminescence intensity comparison test was performed for each ionic structure of sulfur. FIG. 3 shows the relationship between the sulfur concentration and the emission intensity for each ion structure. Sulfuric acid (H ₂ S
O ₄ ), potassium thiosulfate (K ₂ S ₂ O ₃ ), hydrogen sulfide (H
₂ S) Using an absorbing solution and sodium sulfide (Na ₂ S), the measurement was performed under the same conditions.

As is clear from FIG. 3, it can be seen that the emission intensity varies greatly depending on each sulfur ion. The emission intensity is much higher than Na ₂ S, followed by H ₂ S and H ₂ S
O ₄ and K ₂ S ₂ O ₃ show almost the same emission intensity.
This difference in emission intensity at the same concentration of sulfur is a phenomenon not known until now.

This phenomenon can be interpreted as follows.
In ICP analysis, elements such as sulfur, iodine, and phosphorus have analytical lines with strong emission intensity in the vacuum ultraviolet region, and measurement is difficult with ordinary spectrometers due to absorption interference by oxygen in the air. The analysis is made possible by substituting with, and removing the absorption by oxygen. Since the sample is guided by the plasma in the mist state of the aqueous solution and emits light, SO ₄ ^2-
In and S ^₂ O ₃ ^2- ions takes place absorption disturbance for oxygen also simultaneously emit light during light emission is considered that reducing the emission intensity of sulfur. In addition, between SO ₄ ²⁻ and S ₂ O ₃ ²⁻ , there is a difference between 4 atoms and 1.5 atoms of oxygen per 1 atom of sulfur, but no significant difference appears in emission intensity. And Na ₂ S
It can be interpreted that the emission of S ²⁻ ions present in the solution is not disturbed by oxygen and is close to the intrinsic emission intensity of sulfur. This result breaks the conventional wisdom that sulfur is low in ICP analysis.

Since there is a large difference between the emission intensities of the Na ₂ S aqueous solution and the hydrogen sulfide absorbing solution, the ionic structure of sulfur in the absorbing solution cannot be determined as S ²⁻ ion. Therefore, a coloration experiment of S ²⁻ ions was carried out to first confirm the presence of S ²⁻ ions in the absorbing solution.

(Experiment 2) Sodium nitroprusside N
a ₂ [Fe (CN) ₅ (NO)] is converted to S in an alkaline solution.
The presence of S ^{2− in} each sample was confirmed by utilizing the fact that it reacts with ^2- ions to give a purple-red color. An aqueous solution of sulfuric acid, potassium thiosulfate, and sodium sulfide and a hydrogen sulfide absorbing solution are each adjusted to have a sulfur concentration of 10 ppm.
5 ml of each of these is placed in a test tube, and 1 ml of an aqueous sodium hydroxide solution is added thereto to make the solution alkaline, and then 1 ml of a sodium nitroprusside solution is added. The S ²⁻ ion has a reddish purple color, and the S ₂ O ₃ ²⁻ has a red color. As a result of this coloration experiment, sulfuric acid and potassium thiosulfate did not react, and sodium sulfide and the hydrogen sulfide absorbing solution turned red-violet. From this result, the existence of S ²⁻ ions in the hydrogen sulfide absorbing solution was proved.
However S in hydrogen sulfide absorbent solution ^2- ion and S ₂ O ₃ ^2-
It was impossible to analyze that ions were mixed. Assuming that the sulfur in the hydrogen sulfide absorbing solution is all S ^2- ions,
There is a large difference between the emission intensity of the sodium sulfide solution and the emission intensity of the hydrogen sulfide absorbing solution, which causes a contradiction. First, the influence of Na ion and K ion, which are coexisting ions, can be considered as a cause of the difference between them, and an experiment for confirming this was conducted.

(Experiment 3) One of the coexisting ions is sodium and the other is potassium. Therefore, the hydrogen sulfide absorbing solution was mixed with a 0.01% by weight potassium hydroxide solution and 0.01% by weight.
Hydrogen sulfide was bubbled under the same conditions as two types of sodium hydroxide solutions by weight, and the emission intensity of the hydrogen sulfide-absorbed solution was measured by ICP. For the sampling, a mixed gas of N ₂ -H ₂ S (4.5 ppm) was used, and the mixed gas was passed through a 150 ml absorption solution at a flow rate of 1.0 liter / min. FIG. 4 shows the relationship between the sulfur concentration in the sodium hydroxide solution and the potassium hydroxide solution and the emission intensity.
From this figure, it can be said that there is almost no difference between the two. Sodium is an element that emits strong light even in a very small amount compared to potassium. This strong luminescence enhances the background,
As a result, it was supposed that the emission intensity of sulfur was increased,
From the experimental results, it can be said that the emission intensity of sulfur is not affected by coexisting ions.

The state of the presence of sulfur dissolved in the absorption solution will be considered from the oxidation-reduction potential. Most of the chemistry of sulfur in aqueous solution is summarized in the redox potential diagram of FIG. Sulfur is unstable in an alkaline solution and causes a disproportionation reaction to form S ²⁻ ions and S ₂ O ₃ ²⁻ ions. From this, it is considered that the hydrogen sulfide absorbed in the absorbing solution was partially oxidized in the solution, and the emission intensity was lowered due to the mixture of S ²⁻ ions and S ₂ O ₃ ²⁻ ions.

Therefore, in order to prevent oxidation when hydrogen sulfide is absorbed in the absorbing solution, it was studied to add an antioxidant to the absorbing solution. Two antioxidants, L-ascorbic acid and glycerin, were used. The addition concentration was limited to 0.01% by weight in consideration of the influence of the matrix of ICP.

(Experiment 4) 0.01% by weight as an absorbing solution
KOH aqueous solution, 0.01% by weight KOH + 0.01% by weight
L-ascorbic acid aqueous solution, 0.01% by weight KOH +
Hydrogen sulfide was bubbled and absorbed in each of the absorbing solutions using three types of 0.01% by weight glycerin. FIG. 6 shows the relationship between the emission intensity of these absorbing liquids and the change with time. The sampling amount was N ₂ -H ₂ S (45ppm) standard gas 20 l. From the results shown in FIG. 6, it can be seen that the addition of glycerin has almost no antioxidant effect due to the addition, whereas the addition of L-ascorbic acid has an effect of preventing oxidation during bubbling and is oxidized over time. You can see that it goes. From this result, it was clarified that hydrogen sulfide was partially oxidized in the absorbing solution, and S ^{2 −} ions and S ₂ O ₃ ²⁻ ions were mixed, thereby lowering the emission intensity of sulfur. To prevent this, the absorption solution is 0.01% by weight KO
H was added to 0.01% by weight of L-ascorbic acid to prepare an aqueous solution.

According to Experiment 4, the result that L-ascorbic acid is preferable as the antioxidant to be added to the absorbing solution was obtained. However, the same antioxidant effect was obtained, and there was no interference in the ICP analysis. Antioxidants that do not contain the element
For example, various antioxidants such as D or DL-ascorbic acid, hydroxylamine, EDTA, and tocopherols can also be used. It is desirable that the amount of the antioxidant added to the absorbing solution is appropriately set according to the type of the antioxidant to be used and the content of hydrogen sulfide and other impurities contained in the sample gas. In general, the amount of L-ascorbic acid is preferably about 0.01% by weight. However, when the concentration of hydrogen sulfide in the sample gas is high, it is preferable to add more.

In quantitative analysis of hydrogen sulfide in gas,
It was found that it was inappropriate to use sulfuric acid, potassium thiosulfate, or an aqueous solution of sodium sulfide as the standard. That is, when hydrogen sulfide in the sample gas is collected in the absorbing solution for quantitative analysis, similarly, a known concentration of hydrogen sulfide gas is absorbed in the absorbing solution, and the state of ions in the absorbing solution is equal. It turns out that comparison and analysis are optimal. In consideration of these factors, a calibration curve for quantitative analysis of hydrogen sulfide in gas was prepared.

(Experiment 5) Preparation of Calibration Curve FIG. 7 shows a sampling flow of the reference gas and the semiconductor material gas. The absorption bottle and the ball filter used were made of fluororesin. The absorption liquid volume was 150 ml, and the sample flow rate was 1.0 liter / min. The liquid volume, flow rate, and number of absorption bottles are the optimal conditions after the study. Sampling was performed in the order of N ₂ purge sample gas ventilation N ₂ purge. A calibration curve was created using a standard gas. In this case, the standard is X
A solution in which ppm of hydrogen sulfide is absorbed at 1.0 liter / min for 60 minutes is used as a reference solution of Xppm, and a low-concentration reference solution is prepared by shortening the sampling time (that is, by reducing the sampling amount). System.
FIG. 8 shows a calibration curve prepared using this reference solution. The lower detection limit of hydrogen sulfide obtained from the standard deviation when repeatedly measuring ultrapure water using this calibration curve was 50 ppb. The lower limit of detection is generally set to 2 to 3 times the standard deviation, but is set to 10 times the standard deviation in consideration of background stability and reliability of the apparatus.

Further, in order to improve the measurement sensitivity of ICP, an ultrasonic nebulizer was introduced. FIG. 9 shows a principle diagram of an ultrasonic nebulizer, in which reference numeral 91 denotes a spray chamber, 92 denotes a piezo transducer, 93 denotes a heating tube, 94 denotes a condenser, 95 denotes a sample introduction tube,
Reference numeral 96 denotes a vibrator cooling device. In a normal nebulizer, the solution is mist-like with an argon carrier gas, as in the case of spraying. On the other hand, in an ultrasonic nebulizer 90, a sample introduced by a pump is formed into fine mist by a piezo transducer 92 (ultrasonic oscillator). The gas is carried to the heating tube 93 and vaporized. The sample is further conveyed to the condenser 94 for desolvation and concentration, and finally the dried and concentrated sample is conveyed to the plasma torch 4 and used for measurement. Generally, the use of an ultrasonic nebulizer can achieve an order of magnitude increase in sensitivity. FIG. 10 shows a calibration curve created by using the ultrasonic nebulizer 90. There is less variation than a normal nebulizer and the linearity is better. Ultrapure water was measured using this calibration curve, and the detection limit was determined from the standard deviation. The lower limit of detection was 10 times the standard deviation, and the detection limit was 10 ppb.

(Experiment 6) Analysis of hydrogen sulfide in arsine The experimental system diagram is shown in FIG. In the experiment, N ₂ -H ₂ S (9.
4 ppm) mixed gas and H ₂ -AsH ₃ (11%) mixed gas were used to prepare an arsine mixed gas containing 0.56 ppm of hydrogen sulfide by flow mixing; 0.01 wt% KOH and 0.01 wt% L -After bubbling to an absorbing solution containing ascorbic acid, analysis was performed by ICP. The theoretical concentration of hydrogen sulfide in arsine by flow mixing was 0.56 ppm, whereas the value obtained by analyzing the absorbent by ICP was 0.50 pp.
m. Moreover, the result of analyzing only arsine without performing flow mixing was below the detection limit. From this, it was confirmed that hydrogen sulfide in arsine could be accurately analyzed, and that the concentration of hydrogen sulfide in a normal product arsine was below the detection limit.

(Experiment 7) Analysis of hydrogen sulfide in phosphine H ₂ -AsH
_The analysis was carried out in the same manner as in Experiment 6, except that a H ₂ -PH ₃ (46%) mixed gas was used instead of the ₃ (11%) mixed gas.
As a result, while the theoretical concentration of hydrogen sulfide in phosphine by flow mixing was 0.60 ppm, the absorption solution was
The value analyzed for P was 0.63 ppm. Further, the result of analyzing only phosphine without performing flow mixing was below the detection limit.

According to the results of these experiments, the sample gas was brought into contact with an absorbing solution containing an antioxidant, and the hydrogen sulfide in the sample gas was absorbed by the absorbing solution to be collected. Is measured by ICP, and a standard gas containing a known concentration of hydrogen sulfide is passed through the absorbing solution to absorb a predetermined concentration of hydrogen sulfide. By preparing and measuring the hydrogen sulfide concentration of the sample gas from this calibration curve, the content of hydrogen sulfide can be measured with high accuracy without interference even when arsine or phosphine is used as the sample gas. I understood.

[0031]

As described above, according to the method for analyzing hydrogen sulfide of the present invention, a sample gas is brought into contact with an absorbing solution containing an antioxidant to absorb and trap hydrogen sulfide in the sample gas. Then, the absorption liquid that has collected hydrogen sulfide is subjected to ICP, which measures the emission intensity by spectrally analyzing the emission line spectrum of sulfur generated when the element to be measured is excited by plasma. A standard gas containing hydrogen sulfide is passed through the absorption solution to absorb a predetermined concentration of hydrogen sulfide, and the emission intensity is measured by ICP to prepare a hydrogen sulfide calibration curve. This is a method for measuring the hydrogen concentration. By contacting the sample gas with an absorbing solution containing an antioxidant and absorbing and collecting the hydrogen sulfide in the sample gas by the absorbing solution, oxidation when hydrogen sulfide is absorbed is prevented, and S2 ^- ion By analyzing the S ²⁻ ions in the absorbent using ICP, it is possible to quantitatively analyze sulfur with high accuracy without being disturbed by other elements. Therefore, according to the present invention, a conventional flame photometric gas chromatograph (FP) is used.
Unlike the D-GC) method, there is no overlap in the analysis peaks in the analysis of arsine and phosphine, and a trace amount of hydrogen sulfide in arsine and phosphine can be measured with high sensitivity. Further, in the method of the present invention, an ultrasonic nebulizer is used to guide the absorbing solution to the plasma torch of the inductively coupled high frequency plasma spectrometer, which is one order of magnitude lower than the conventional colorimetric method. Measurement at the detection limit becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing the measurement principle of ICP used in the hydrogen sulfide analysis method of the present invention.

FIG. 2 is a schematic diagram for explaining the hydrogen sulfide absorption operation in Experiment 1.

FIG. 3 is a graph showing the results of Experiment 1.

FIG. 4 is a graph showing the results of Experiment 3.

FIG. 5 is an oxidation potential diagram of sulfur in an alkaline solution.

FIG. 6 is a graph showing the results of Experiment 4.

FIG. 7 is a schematic diagram illustrating a sampling device used in Experiment 5.

FIG. 8 shows a first example of a calibration curve prepared in Experiment 5, which is a calibration curve when a normal nebulizer is used.

FIG. 9 is a schematic diagram showing an ultrasonic nebulizer used in Experiment 5.

FIG. 10 shows a second example of a calibration curve created in Experiment 5.
It is a calibration curve at the time of using an ultrasonic nebulizer.

FIG. 11 is a schematic diagram showing a sampling device used in Experiments 6 and 7.

FIG. 12 illustrates the results of analyzing hydrogen sulfide using a flame photometric gas chromatograph, which is one of the conventional methods for quantifying hydrogen sulfide, wherein (a) shows the analysis results of N ₂ -H ₂ S, b)
Indicates the analysis results of H ₂ -PH ₃ -H ₂ S, respectively.

[Explanation of Signs] 1 ... Spectroscope, 2 ... Photomultiplier tube, 3 ... Plasma,
4 plasma torch, 5 high-frequency power supply, 6 automatic gas control mechanism, 7 argon gas source, 8 photometric system, 9 computer, 10 display, 1 display
1 ... printer, 12 ... floppy disk, 13 ...
... sample solution, 20 ... standard gas source, 21 ... absorbing solution, 2
2 ... absorption bottle, 90 ... ultrasonic nebulizer, 91 ... spray chamber, 92 ... piezo transducer, 93 ...
... heating tube, 94 ... condenser, 95 ... sample introduction tube, 96 ... vibrator cooling device.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eitoku Ikubo 10 Okubo, Tsukuba, Ibaraki Prefecture, Japan Tsukuba Research Laboratories (72) Inventor Isao Matsumoto 10 Okubo, Tsukuba, Ibaraki Prefecture, Japan Tsukuba Research Laboratories ( 56) References JP-A-5-52753 (JP, A) JP-A-64-53135 (JP, A) JP-A-64-6748 (JP, A) JP-A-5-149842 (JP, A) Yasuhiro Takahashi Et al., “Development of a method for analyzing hydrogen sulfide in arsine and phosphine,” Nippon Oxygen Technical Report, No. 11, Page. 31-38, 192.1.2.1 Published by Nippon Sanso Corporation (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/62-21/74 G01N 1/00-1/34 JICST file (JOIS )

Claims (2)

(57) [Claims] 1. A sample gas is brought into contact with an absorbing solution containing an antioxidant, hydrogen sulfide in the sample gas is absorbed by the absorbing solution and collected, and then the absorbing solution obtained by collecting hydrogen sulfide is measured. The emission intensity is measured by an inductively-coupled high-frequency plasma spectrometer that spectrally analyzes the emission line spectrum of sulfur generated when the element is excited by plasma and measures the emission intensity. The solution in which the predetermined concentration of hydrogen sulfide was absorbed by flowing into the absorbing solution was measured for the emission intensity by inductively coupled high-frequency plasma spectroscopy to create a hydrogen sulfide calibration curve, and the hydrogen sulfide concentration of the sample gas was determined from the calibration curve. A method for analyzing hydrogen sulfide, characterized by measuring. 2. When the absorbing solution is guided to a plasma torch of an inductively coupled high-frequency plasma spectrometer, the absorbing solution is mist-formed by an ultrasonic vibrator, and is supplied while heating with a carrier gas to supply a concentrated sample. 2. The method for analyzing hydrogen sulfide according to claim 1, wherein an ultrasonic nebulizer is used.