JPH08178841A - Infrared analytic method - Google Patents

Abstract

PURPOSE: To realize an infrared analysis even for a trace of liquid sample or a liquid sample having a low surface tension or high volatility by making a recess in the surface of an easily moldable plate-shaped window member excellent in light transmissivity, dripping a sample liquid into the recess and then performing the infrared analysis. CONSTITUTION: A recess 2 is made in an easily deformable plate-shaped window material of potassium bromide KBr excellent in light transmissivity and then a liquid sample 5a is dripped therein and analyzed. The recess 2 has an opening of lengths L1, L2 of about 1.0mm and 50μm and the maximum depth of about 30μm. When a sample is subjected to infrared analysis using such window member 1a, an appropriate quantity of the sample 5a is dripped into the recess 2. The sample 5a is contained in the recess 2 while bulging due to surface tension thus providing the film thickness of about 40μm. Since the sample is exposed to the outside, a nonvolatile sample is preferably employed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared analysis method applicable to infrared analysis of a liquid sample such as an organic material.

[0002]

2. Description of the Related Art Infrared (IR) analysis is performed by using an infrared microscope, and is also called infrared absorption spectrum method. It is a continuous infrared wavelength for a liquid sample such as an organic material such as alcohol or ketone. It is known as a method for obtaining an absorption spectrum according to the molecular structure of an irradiated molecule by irradiating the molecule while changing the temperature, and analyzing the molecular structure from the spectrum. Conventionally, two methods are known as methods for infrared analysis of a liquid sample.

1) A method in which a liquid to be analyzed is put into a commercially available liquid cell for analysis (method using a liquid cell).

2) A method in which a window material such as potassium bromide (KBr) is used and a liquid to be analyzed is directly dropped on the window material for analysis (a method using the window material).

[0005]

These conventional sample preparation methods have the following problems.

First, in the first method using a liquid cell, since the liquid cell has a large capacity (eg, several cc), several meters are required.
It is not possible to handle trace liquid samples below 1 l.

Secondly, in the infrared analyzer having a fixed focal length, the focal length of the Cassegrain mirror with respect to the sample position is short, and it is not possible to make room for the liquid cell.

Thirdly, since the focal length of the infrared device (infrared microscope) is fixed, it is difficult to adjust the refracted light of infrared light to pass through the liquid cell.

Next, in the second method using a window material, in the case of a highly volatile liquid sample, even if this liquid sample is dropped on the window material, the liquid sample will immediately volatilize, so that the measurement can be performed. Have difficulty.

Further, in the case of a liquid sample having a weak surface tension, the film thickness of the sample tends to be insufficient, so that the amount of infrared absorption spectrum is insufficient and a clear spectrum peak cannot be obtained.

Therefore, the present invention provides an infrared analysis method capable of performing infrared analysis even for a small amount of a liquid sample, a liquid sample having a small surface tension, or a liquid sample having high volatility. With the goal.

[0012]

In order to solve the above-mentioned problems, in the present invention, there is provided an infrared analysis method for infrared analysis of a liquid sample, the surface of a plate-shaped window material being excellent in light transmittance and easy to mold. Infrared analysis is performed in a state where a concave portion is formed in the concave portion and a liquid sample is dropped and contained in the concave portion.

[0013]

As shown in FIGS. 1 to 3, the plate-like potassium bromide (KBr) window material 1a is excellent in light transmittance and easy to form, and the recess 2 is formed in the window material 1a.
Since it is possible to form and form a liquid sample in the concave portion 2 and store the liquid sample for analysis, it is possible to obtain an appropriate film thickness even if the liquid sample is a minute amount.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In this example, as shown in FIG. 1A and FIG. 1B as a sectional view taken along the line AA, the window material for accommodating the liquid sample for infrared analysis is light transmissive in consideration of infrared transmission. A plate material (pallet) which is excellent in heat resistance and easy to mold as described later is used. In this example, a potassium bromide plate is used as the window material. Its thickness is 150-2
It is 50 μm. In this example, a recess 2 having a semi-cylindrical cross section is formed to accommodate the sample in the substantially central portion of the window material 1a. A method of forming the recess 2 will be described later.

The size of the recess 2 is, in this example, the opening length L.
1 and L2 were 1.0 mm and 50 μm, respectively, and the maximum depth was about 30 μm.

To perform infrared analysis of a sample (liquid sample) using the window material 1a thus constructed, the window material 1a is used.
An appropriate amount of a sample (organic material or the like) 5a to be analyzed is dropped into the concave portion 2 and stored. Then, the liquid sample 5a is shown in FIG.
As shown in (c), it is accommodated in the concave portion 2 and its surface is convex due to surface tension, so that the film thickness is about 40 μm.

The liquid sample used in this embodiment is preferably a non-volatile liquid which is hard to volatilize because the liquid surface is exposed to the outside.

The following method can be used to form the recess 2 in the window member 1a.

First, as shown in FIG. 2A and its sectional view taken along the line BB in FIG. 2B, a circular plate-shaped window material (potassium bromide) 1a having a thickness of about 200 μm is formed into a circular mirror. Face plate 3a
Put it on top. Next, the outer diameter 15
The glass pipette piece 7 of about 0 μm is attached to the window member 1
Place on a.

After that, as shown in FIG. 3A, one circular mirror plate 3b is placed on the micropipette piece 7 and lightly pressed by a hand press (not shown) or the like. When the pressure is applied, as shown in FIG. 3B, the lower portion of the micropipette piece 7 bites into the window member 1a by a predetermined amount.

Next, when the mirror plates 3a and 3b and the micropipette piece 7 are removed from the window member 1a, as shown in FIG. 3C (see also FIG. 1), the micropipette piece 7 is formed at the substantially central portion.
As a trace of, the recess 2 having a semi-cylindrical cross section is formed.

By changing the size of the micropipette piece 7 or changing the amount of pressurization, the shape and size of the recess 2 can be changed as appropriate, so that the sample amount and the film thickness at the time of analysis can be made relatively small. It can be easily adjusted.

In this example, the glass cylindrical micropipette piece 7 is used for forming the concave portion, but any micropipette piece harder than the window material 1a can be used instead of the glass material.

Since the surface of the sample is exposed to the outside air only by using one window member 1a, it is not suitable for infrared analysis of a volatile sample. In the case of a volatile sample, two window materials 1a may be used. The same applies to samples with low surface tension. Explaining an example thereof, a liquid sample having high volatility and a liquid sample 5b having a small surface tension as shown in FIG. 4 are prepared by first forming the concave portion 2 of the window material 1a made of potassium bromide as in the first embodiment. A predetermined amount is stored in the inside.
After that, the circular plate-shaped window material 1b is placed on the circular plate-shaped window material 1a to cover the surface of the concave portion 2. Although the window member 1b has no recess, it has substantially the same shape as the window member 1a. With this, the pressurization can be integrated. The thickness thereof may be slightly thinner than that of the window material 1a.

With the window material 1b placed on the window material 1a,
As shown in FIG. 4A, the upper and lower sides are sandwiched by circular mirror plates 3a and 3b larger than the window members 1a and 1b, and in that state, the mirror plate 3
The outsides of a and 3b are lightly pressed by a hand press (not shown) to bring the window materials 1a and 1b into close contact with each other. In this way, even if the mirror plates 3a and 3b are removed as shown in FIG.
Since the liquid sample 5b is sealed with the window materials 1a and 1b, infrared analysis can be performed even for a liquid having high volatility or a sample having low surface tension.

[0026]

As described above, according to the present invention, the liquid sample can be dropped and accommodated in the concave portion of the window member, so that an appropriate film thickness can be obtained even when the liquid sample is in a very small amount, and S for infrared analysis
/ N can be improved.

In addition, if a liquid sample is dropped and contained in the concave portion of the window material and another window material or the like is covered and hermetically sealed as needed, infrared analysis can be performed on a liquid having a low surface tension or a liquid with high volatility. It has features such as enabling.

Further, the present invention is less expensive than using commercially available liquid cells.

[Brief description of drawings]

FIG. 1 is an explanatory view of a window member recess.

FIG. 2 is an explanatory view (I) of forming a window member recess.

FIG. 3 is an explanatory view (II) of forming a window member recess.

FIG. 4 is a diagram for explaining a liquid sample.

[Explanation of symbols]

 1a, 1b Window material 2 Recesses 3a, 3b Mirror surface plate 5a, 5b Liquid sample 7 Micropipette piece

Claims (4)

[Claims] 1. An infrared analysis method for infrared analysis of a liquid sample, comprising: forming a recess on the surface of a plate-like window material having excellent light transmission and being easy to mold, and dropping the liquid sample into the recess. The infrared analysis method is characterized in that the infrared analysis is performed in a state. 2. The infrared analysis method according to claim 1, wherein potassium bromide is used as the plate window material. 3. The recess is formed by placing a glass micropipette piece on the window member and pressing the micropipette piece.
Infrared analysis method described. 4. The liquid sample in a state where the liquid sample is accommodated in the recess of the first plate-shaped window member and the recess is covered with the second plate-shaped window member to seal the liquid sample. The infrared analysis method according to claim 1, wherein the infrared analysis is performed.