JPH08254484A - Condensing method and device for sample of aqueous solution - Google Patents

Abstract

PURPOSE: To prevent contamination caused environmentally at the time of condensing operation and make accurate quantification of impurities by encapsulating a sample of aqueous solution using a porous film and dispersing the water vapor to the outside through the porous film when the sample is heated so that the water is evaporated. CONSTITUTION: From a sample supplying device 1 a sample of aqueous solution is supplied to a condensation trough 3 whose over-part is enclosed with a poroud film 2. The film 2 admits passage of water vapor but shuts off fine particles, for example of Teflon, and its pore diameter is selected in accordance with the environment applicable, ranging 0.1-10μm normally. The sample in the trough 3 is heated by a trough heating device 4 which uses an infrared lamp, and the water is thereby evaporated while the condensed solution is collected by a vessel 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for concentrating an aqueous solution for quantifying impurities dissolved or suspended in the aqueous solution. INDUSTRIAL APPLICABILITY The present invention is used in the field of quality control of pure water, acid, alkaline aqueous solution, etc. used for semiconductor manufacturing and the like.

[0002]

2. Description of the Related Art In recent years, pure water, acid and alkali aqueous solutions and the like required for semiconductor manufacturing have been highly purified. In particular, S
a heavy metal such as Fe, Ni, or Cr that forms a level in the band gap of i and greatly affects the characteristics of the semiconductor;
Alkali metals such as Na and K that exist as ion carriers on the semiconductor surface and cause electric leakage must be controlled to ppb or less. For that purpose, it is necessary to accurately quantify these impurities in pure water, an acid and an alkaline aqueous solution. However, current analytical techniques cannot directly analyze these aqueous solution samples due to lack of sensitivity. 1
It must be concentrated about 100 times. As a method of concentrating an aqueous solution sample, a method of heating an aqueous solution sample placed in a beaker with a hot plate or an infrared lamp to evaporate water has been generally used.

[0003]

In the above-mentioned concentration method, fine particles fly into the aqueous solution from the environment of the operator or peripheral equipment during concentration, which causes a large error in measurement.

The present invention provides a method and an apparatus for concentrating an aqueous solution sample by preventing contamination by fine particles from the environment.

[0005]

Means for Solving the Problems The method of concentration of the present invention is a porous membrane that allows water vapor from a heated aqueous solution sample to pass therethrough and does not allow fine particles from the environment to pass when the aqueous solution sample is heated to evaporate water. It is a method of concentrating an aqueous solution sample by sealing the aqueous solution sample and preventing contamination from the environment.

An apparatus for realizing this in a batch system is a sample solution supply device for supplying an aqueous solution sample to a concentration tank sealed with a porous membrane and a concentrated aqueous solution sample. Is connected to the concentrated sample solution collecting container, and the concentrating tank heating device is arranged so that the aqueous solution sample in the concentrating tank can be heated.

A device for continuously realizing is
A sample supply device for supplying an aqueous solution sample and a concentrated sample solution collection container for collecting the concentrated aqueous solution sample are respectively connected to both ends of the concentration tube made of a porous membrane, and the inside of the concentration tube A concentrating tube heating device is arranged so that the aqueous solution sample can be heated.

[0008]

First, a method of concentrating an aqueous solution sample in a batch system will be described. The aqueous solution sample is supplied to the concentration tank by the sample supply device. The sample amount depends on the concentration of the aqueous solution sample, but 10 to 1000 ml is needed to complete the concentration in a short time.
Is desirable. The concentrator is sealed with a porous membrane that allows water vapor to pass but does not allow particulates to pass. The porous membrane is made of Teflon,
Although it may be made of cellulose, it is preferably made of Teflon from the viewpoint of resistance to acid and alkali. The pore size of the porous membrane varies depending on the environment in which it is used, but normally 0.1 to 10 μm is desirable. Next, the aqueous solution sample in the concentrating tank is heated by the heating device to evaporate the water. The heating device may use an infrared lamp, a hot plate, or both. The water vapor from the aqueous solution sample permeates the porous membrane and diffuses to the outside, but since the fine particles from the outside do not reach the aqueous solution sample inside, contamination can be prevented from the environment during the concentration operation. The concentrated sample solution is collected in the concentrated sample solution collecting container without coming into contact with the external environment. By analyzing the obtained concentrated sample solution, it is possible to perform highly accurate analysis without errors due to contamination.

Next, a method for continuously concentrating an aqueous solution sample will be described. The sample supply device continuously supplies the aqueous solution sample to the concentration tube. The concentrating tube is made of a porous film that allows water vapor to pass but does not allow particles to pass, and the material may be either Teflon or cellulose,
It is preferably made of Teflon from the viewpoint of resistance to acid and alkali. The pore size of the porous membrane varies depending on the environment in which it is used, but normally 0.1 to 10 μm is desirable. The inner diameter, length and delivery amount of the concentration tube depend on the concentration of the aqueous solution sample, but in order to complete the concentration in a short time, the inner diameter is 0.5 to 10 mm, the length is 1 to 100 m, and the delivery amount is 0. .5
~ 50 ml / min is desirable. Next, the heating device heats the aqueous solution sample in the concentrating tube to evaporate the water. It is desirable to coil the concentrating tube for efficient heating. The heating device may use an infrared lamp, a hot plate, or both. Similar to the batch-type aqueous solution sample concentration method, contamination from the environment is prevented, the aqueous solution sample is concentrated, and the concentrated sample solution is collected in the concentrated sample collection container.

[0010]

EXAMPLE In FIG. 1, a porous membrane is used to prevent contamination from the outside, leave impurities in the aqueous solution sample from the heated aqueous solution sample, and separate water,
An example of the apparatus which concentrates an aqueous solution sample in a batch type is shown typically.

From the sample solution supply device 1, 200 ml of an aqueous solution sample is supplied to a concentrating tank 3 having a length of 50 mm, a width of 50 mm and a height of 100 mm, which is closed by a porous membrane 2. Porous membrane 2
Was a Teflon separation membrane having a pore size of 1.0 μm and a thickness of 1 mm. Next, a concentrator heating device 4 using an infrared lamp
According to, the aqueous solution sample in the concentrating tank is heated to evaporate water and concentrate. The infrared lamp was installed above the concentrating tank.
The concentrated solution is collected in the concentrated sample solution collecting container 5.

FIG. 2 schematically shows an example of an apparatus for continuously concentrating an aqueous solution sample. An aqueous solution sample is supplied from the sample solution supply device 1 to the concentration tube 6 made of a porous film. The feed rate was set to 5 ml / min. As the concentrating tube 6, a Teflon separation membrane tube having a pore diameter of 1.0 μm, a thickness of 1 mm and an inner diameter of 1 mm was used. The length of the concentration tube is 1
The length was 0 m, and the shape was a coil with a diameter of 20 cm. next,
The concentration tank heating device 7 using an infrared lamp heats the aqueous solution sample in the concentration tube to evaporate and condense water. The infrared lamp was installed above the coiled concentrating tube. The concentrated solution is a concentrated sample solution collection container 8
To collect continuously.

FIG. 3 shows a sample obtained by concentrating 200 ml of pure water to 5 ml (40 times concentrated) with the apparatus of FIG. 1 and class 100.
Put pure water into a 300 ml beaker in the clean room of
A sample obtained by heating and evaporating with a hot plate of a conventional method and concentrating 40 times was analyzed for Fe by an inductively coupled plasma mass spectrometer, and the obtained signal is shown. Five samples were concentrated by each method and analyzed, but in the sample concentrated by the conventional method, the dispersion of the analysis values is large due to contamination from the environment, and the average of the analysis values is also high.

[0014]

EFFECTS OF THE INVENTION By using the concentration method and apparatus of the present invention, it is possible to prevent contamination from the environment during concentration operation, and it is possible to accurately quantify impurities in an aqueous solution sample. Therefore, it has a great effect on the field of quality control of pure water, acid, and alkaline aqueous solution used for semiconductor manufacturing and the like.

[Brief description of drawings]

FIG. 1 is an example of an aqueous solution sample concentrating device that performs the method of the present invention in a badge manner.

FIG. 2 is an example of an aqueous solution sample concentrating device for continuously performing the method of the present invention.

3 is a result of Fe determination of pure water concentrated using the apparatus of Example 1 shown in FIG. Inductively coupled plasma mass spectrometry was used to quantify Fe.

[Explanation of symbols]

 1 Sample Solution Supply Device 2 Porous Membrane 3 Concentration Tank 4 Concentration Tank Heating Device 5 Concentrated Sample Solution Collection Container 6 Concentration Tube 7 Concentration Tube Heating Device 8 Concentrated Sample Solution Collection Container

Claims (3)

[Claims] 1. When the aqueous solution sample is concentrated by evaporating water by heating the aqueous solution sample, the aqueous solution sample is sealed with a porous membrane, and water vapor from the aqueous solution sample permeates through the porous membrane to the outside. A method for concentrating an aqueous solution sample, characterized by diffusing into an aqueous solution. 2. A concentration tank sealed with a porous membrane, a sample solution supply device for supplying an aqueous solution sample to the concentration tank, and a concentrated sample solution collection container for collecting the concentrated aqueous solution sample. An aqueous solution sample concentrating device, which is connected and in which a concentrating tank heating device is arranged so that an aqueous solution sample in the concentrating tank can be heated. 3. A sample supply device for supplying an aqueous solution sample and a concentrated sample solution collection container for collecting the concentrated aqueous solution are connected to both ends of a concentrating tube made of a porous membrane, respectively. An aqueous solution sample concentrator in which a concentrating tube heating device is arranged so that the aqueous solution sample in the tube can be heated.