JPS62840A - Analysis of phosphorus - Google Patents

Abstract

PURPOSE:To quantitatively analyze phosphorus with high accuracy by adding nitric acid and perchloric acid having ultra-high purity to a sample to be analyzed, electrically heating the sample and introducing the evaporated phosphorus into the argon plasma generated by 10-40MHz high-frequency induction heating. CONSTITUTION:An org. material, more particularly bacteria which are the sample to be analyzed are sampled directly into a boat made of a high melting and nitric acid and perchloric acid having the high purity are added thereto. The sample is electrically heated in an inert gas and is thereby decomposed and incinerated; thereafter the sample is heated to 1,500-2,500 deg.C (more preferably 1,700-2,200 deg.C) to be evaporated. The evaporated matter is introduced into the argon plasma generated by 10-40MHz high-frequency induction heating. The phosphorus is quantitatively analyzed from the emission intensity of the excited light. The phosphorus is thereby quantitatively analyzed easily and quickly with the high sensitivity and high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for analyzing phosphorus in organic substances, particularly bacteria.

[Technical background of the invention and its problems]

The most important issue in semiconductor manufacturing is process cleanliness. As is well known, this is a product defect caused by dust. As a countermeasure for these problems, it is desirable to improve the cleanliness of the entire room as much as possible.

Currently, this level of cleanliness has improved through various improvements 42, but in order to further raise the level, ζ2 has been improved at each manufacturing facility.

It is desirable to prevent the generation of dust and to make the entire room completely unmanned. However, this is currently extremely difficult.

Even the bacteria present in the ultra-super clean rooms, which are currently the most advanced, are becoming a problem.

Therefore, quantifying indoor bacteria is an important element in environmental management, and for this purpose, it is extremely important to quantify bacteria in a short time and with high precision, and to feed back the data for environmental management.

In other words, the present invention directly analyzes the bacteria that is the sample to be analyzed.
The sample is collected on a high melting point metal port, high purity nitric acid and perchloric acid are added, electrically heated in an inert gas, separated, ashed, and evaporated in succession, and the vaporized phosphorus is placed in an argon plasma. The unique feature is that phosphorus is introduced into the system and phosphorus is quantified from the excitation emission intensity.

Generally, molybdenum blue spectrophotometry is used to analyze phosphorus, and this method can also be used to analyze phosphorus in bacteria. This method is a colorimetric measurement of a blue substance of unknown structure that is produced by reducing phosphomolybdic acid, which is produced by adding molybdic acid and ammonium solution to a sample bath containing phosphate ions, with tin(I) chloride, hydracide, hydroquinone, etc. It is determined by the method.

However, in this method, the color development not only depends on the acidity of the liquid, the type and amount of reagents, the reaction time, etc., but also has a large influence on temperature. Furthermore, arsenate ions and large amounts of reactive silicates exhibit similar reactions and prevent the determination of phosphate ions. Therefore, it is essential to adjust the reaction temperature and acidity during analysis, and it is difficult to say that this method is satisfactory in terms of ease of analysis, analysis time, and accuracy.

[Purpose of the invention]

The present inventors have developed a quantitative analysis method for phosphorus that has a higher quantitative ratio and higher accuracy than the conventional method for quantitative analysis of phosphorus. As a result of our studies, we have completed the present invention.

[Summary of the invention]

In the invention, organic matter, especially bacteria, to be analyzed is collected directly into a high-melting metal boat, and high-purity nitric acid and perchloric acid are added to it, electrically heated in an inert gas, decomposed, and incinerated. ~2500C (preferably 1700C
~220t) C) to evaporate and evaporate 10~40t)
Argon plasma generated by MHz high-frequency induction heating) is introduced, and phosphorus is quantified from the excitation emission intensity, which is simple, quick, and highly sensitive.

The objective is to provide an analytical method that allows for highly accurate quantification.

In the present invention, nitric acid and perchloric acid are used in order to strengthen the oxidizing power of perchloric acid, and it is preferable to use nitric acid in combination to prevent danger. In addition, when heating on a high-melting point metal boat at temperatures above 1500 C, the coloring intensity of phosphorus becomes unsaturated and the 4m axiality of the data becomes poor. This is not desirable because it reaches its usage limit.

[Embodiments of the Invention] Example 1 10 μg of a sample was collected in a quartz beaker, and 3 m of nitric acid was added to it.
e. Add 1 ml of perchloric acid and heat decompose on a hot plate. The temperature at this time is from 150 t:' to 160 t:',
The obtained bath solution was made up to a volume of 100 ml in volumetric flask 1 with pure water. A certain amount (20 μm) of this sample solution was collected with a micropipette, directly injected onto a metal (tungsten) boat, and heated to 100C as shown in Table 1.
After drying for 130 seconds and ashing at 20oc for 30 seconds,
Heated at 300 C for 16 seconds and introduced into argon plasma generated by high frequency induction heating at 27.12 MHz.
Phosphorus was quantified from the excitation emission intensity.

Example 2 10 μg of sample was collected directly into a metal (tungsten) boat, and a few drops of nitric acid and a few drops of perchloric acid were added thereto.
Thereafter, phosphorus was determined from the excitation emission intensity under the same conditions and with the same operations as in Example 1.

Table 1: Comparison example of high frequency induction goods and 7 emission spectroscopy measurement conditions The operation of the molybdenum blue spectrophotometry method is described below.

As in the example, 10 μg of the sample was collected in a quartz beaker,
Add 1 m4 of nitric acid and 1 m-e of perchloric acid and heat decompose on a hot plate. A molybdate solution and a hydrazine sulfate solution as a reducing agent were added to this solution.

A blue liquid was obtained. The obtained sample was adjusted with pure water, heated in a boiling bath for 10 minutes, cooled to room temperature, and heated with a colorimetric needle &
: The absorbance was measured at a wavelength of 830 nm.

FIG. 1 shows an example of the emission intensity with respect to temperature change during high-temperature vaporization of phosphorus.

The results obtained under these analytical conditions are shown in Table 2.

Table 2: It is clear from the above results that the present invention requires a short time for one analysis, can perform IA waiting time analysis using the conventional method, and has a wide analysis range.

〔Effect of the invention〕

The present invention: Since Futayore can fully utilize the high sensitivity of evaporation-induced plasma emission spectroscopy, it has become possible to analyze phosphorus below 0.1 ppm, which was previously impossible to quantify. Also, the analysis range becomes very wide.

And now it can be easily analyzed.

Furthermore, by using bacteria as the phosphorus analysis sample of the present invention, it has become possible to efficiently quantitatively analyze bacteria.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the luminescence intensity with respect to temperature changes for determining high temperature vaporization under the measurement conditions used in the present invention.

Claims (1)

[Claims] 1) A sample to be analyzed is collected on a high melting point metal port, ultra-high purity nitric acid and perchloric acid are added, and electrically heated in an inert gas to decompose, ash, and evaporate. A method for analyzing phosphorus, characterized in that the vaporized phosphorus is introduced into an argon plasma generated by high-frequency induction heating at 10 to 40 MHz, and the phosphorus is quantified from the excitation emission intensity. 2) The phosphorus analysis method according to claim 1, wherein the evaporation temperature is 1500 to 2500°C. 3) The method for analyzing phosphorus according to claim 1, wherein the sample to be analyzed is organic matter, especially bacteria.