JP3093329B2 - Microspectroscopic analysis method and sample table used for the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microspectroscopic analysis method and a sample table used for the method.

[0002]

2. Description of the Related Art For example, a micro-spectroscopic analysis method using a microscopic FTIR (Fourier transform infrared spectrophotometer), an FTIR with a beam condenser, and an FTIR with a condenser lens is a method suitable for analyzing minute and minute amounts of organic substances. However, in the conventional means for condensing a very small amount of sample, the condensed sample diffuses and becomes thinner, which is a bottleneck for high-sensitivity analysis.

[0003] That is, conventionally, a small amount of a solution containing a sample in a solvent is dropped on a mirror-finished metal base using an instrument such as a fractionator, and the solvent in the solution is evaporated. The sample is condensed on the base.

[0004]

However, in this condensing means, the solution dropped on the base spreads as if licking the mirror surface of the base, and the sample diffuses and condenses in an island shape. Was reduced in thickness.

More specifically, when 1 μl of a solution obtained by dissolving 10 μl of liquid paraffin in 100 ml of acetone is dropped on a base, this solution immediately spreads to 3 to 5 mmφ, and the solvent is spread from the periphery. At the same time as the evaporation started, the dissolved samples became innumerable islands, which condensed into a 3 to 5 mmφ ring and became extremely thin.

[0006] This is insufficient absorption intensity of the infrared ray, was measured for transmittance in the infrared by microscopic FTIR / FT-530 (manufactured by Horiba Ltd.), as shown in FIG. 11, in the vicinity wavenumber 1450 cm ^-1 Has an infrared transmittance of 9
It was about 8%, and the absorbance was extremely low at 0.01, making it difficult to perform high-sensitivity analysis by microspectroscopy.

The present invention has been made in view of such circumstances, and has developed a means for aggregating and condensing a sample so that even if the sample is minute and minute, it can be used with high sensitivity. It is an object of the present invention to provide a microspectroscopic analysis method which can be analyzed by the above method, and a sample table suitable for the method.

[0008]

The microspectroscopic analysis methods according to the first, second and third inventions which have achieved the above objects are so-called infrared reflection type analysis methods, and the microspectroscopic analysis method according to the fourth invention. The method is a so-called infrared transmission type analysis method.

That is, in the infrared reflection type microspectroscopic analysis method according to the first invention, a trace amount of a solution containing a sample in a solvent is dropped on a fluororesin thin film attached to an infrared reflection member of a sample table. The solvent in the solution is evaporated to condense the sample, and the condensed sample is placed in the micro-spectroscopic analysis unit with the sample table pressed, and the condensed sample pressed and flattened by the pressurizing means is irradiated with infrared rays, and the condensed sample is condensed. It is characterized in that the spectrum reflected from the infrared reflecting member through the sample is measured.

According to a third aspect of the present invention, there is provided an infrared reflection infrared transmission type microspectroscopic analysis method in which a small amount of a solution containing a sample in a solvent is dropped on a base of a fluororesin, and the solvent in the solution is evaporated. To condense the sample, transfer the condensed sample to an infrared reflecting member, position the transferred sample together with the infrared reflecting member in the microspectroscopic analysis section, irradiate the condensing sample with infrared light, and pass the infrared reflecting member through the condensing sample. Is characterized by measuring the spectrum reflected from the.

[0011]

In the infrared transmission type microspectroscopic analysis method according to the fourth invention, a trace amount of a solution containing a sample in a solvent is dropped on a base of a fluororesin, and the sample in the solution is evaporated by evaporating the solvent in the solution. The condensed sample is transferred to an infrared transmitting member, and the transferred sample is placed together with the infrared transmitting member in the micro-spectroscopic analysis section, and the condensing sample is irradiated with infrared light, and the spectrum transmitted through the condensing sample and the infrared transmitting member is conveyed. Is measured.

Meanwhile, fifth shots Ming is an invention relating to a sample stand, the sample table according to the fifth invention, the infrared ray transmitting member for transferring the base of the fluorine-based resin, a sample that has been condensed on the base The feature is that it consists of

[0014]

According to the first to fourth aspects of the present invention, since the fluororesin is highly water-repellent in nature, the solution dropped on the surface of the fluororesin is limited in its diffusion and is spherical due to surface tension. And, as the solvent evaporates, the diameter of the sphere gradually decreases, so that the non-volatile substance, that is, the sample, is coagulated and concentrated, and finally a condensed sample having a small spread and a large thickness is obtained. .

[0015] As the thickness of the condensed sample is increased, the infrared absorption intensity of the sample in the micro-spectroscopic analysis unit is increased. As a result, even if the sample is minute and minute, it can be reduced. Analysis can be performed with high sensitivity by an analysis method based on reflection or transmission of infrared rays.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a principle diagram for explaining a micro-spectroscopic analysis method by reflection of infrared rays according to the present invention.
1 is a sample table for supporting the sample S, for example, FT
It is located in the IR microspectroscopy section.

Reference numeral 2 denotes a sample S on the sample table 1 with an infrared ray IR.
A light source 3 for irradiating the sample 3 is a spectrum measuring device for measuring a reflection spectrum of the infrared ray from the sample S. Based on the measurement information of the reflection spectrum by the measuring device 3, quantitative analysis and qualitative analysis of the sample are performed. Done.

The sample table 1 in this embodiment has a thickness of, for example, 25 .mu.m (for example, 16 .mu.m or 8 .mu.m from the viewpoint of suppressing infrared absorption) on the mirror surface portion of the mirror-finished metallic infrared reflecting member 4. The thinner is preferable.) The measuring device 3 measures the spectrum reflected by the infrared reflecting member 4 through the sample S and the thin film 5 of the fluororesin. I do.

The fluororesin thin film 5 is coated, for example, on an infrared transmitting member (for example, a crystal or a film of an alkali halide material such as KBr or NaCl), and the fluororesin thin film 5 is passed through the infrared transmitting member. According to such a configuration, when a pinhole exists in the fluororesin thin film 5, the pinhole is filled with an infrared transmitting member,
The permeation of the solution between the fluororesin thin film 5 and the infrared reflecting member 4 is effectively prevented.

On the other hand, the sample S is an eluate separated by, for example, liquid chromatography, and is carried on the fluororesin thin film 5 as follows. That is, as shown in FIG. 2, a small amount of a solution containing the sample S in a solvent is dropped on the fluororesin thin film 5 using an instrument such as a fractionator.

At this time, since the fluororesin thin film 5 is highly water-repellent in nature even when methanol or ethanol is selected as the solvent, the solution dropped on the fluororesin thin film 5 is used. Has a limited diffusion and will remain spherical due to its surface tension.

As shown in FIG. 3, when the solvent in the solution is evaporated (natural evaporation or forced evaporation with a heater or the like), the solution is reduced in diameter while maintaining a spherical shape, and the non-volatile substance, that is, the sample S is aggregated. As a result, the condensate of only the sample S is formed on the fluororesin thin film 5 as shown in FIG.

The condensed sample S is thick and has a small spread due to the diffusion limitation of the solution in the process up to that point.
When 1 μl of a solution dissolved in 00 ml of acetone is dropped on the fluororesin thin film 5, the solution has a spherical shape, the solvent evaporates from the periphery of the spherical surface, and the sample S has a thickness of about 100 μmφ. Condensed into a circular shape.

The condensed sample S is placed in the micro-spectroscopic analysis section along with the sample stage 1 for micro-spectroscopic analysis. Preferably, as shown in FIG. Pressing and flattening to improve the measurement sensitivity.

Since the thickness of the above-mentioned condensed sample S is large, the infrared absorption intensity of the sample S in the micro-spectroscopic analysis unit is increased, and the infrared light is absorbed by the micro FTIR / FT-530 (manufactured by Horiba, Ltd.). When the transmittance was measured,
As shown in FIG. 10, the transmittance of infrared rays near the wave number of 1450 cm ^-1 is about 10%, the absorbance is extremely high at 1.0, and the absorbance ratio is 100% higher than that of the conventional means described above.
Sample analysis by reflection spectrum measurement is achieved with high sensitivity (100 times higher sensitivity than before).

The solvent in the solution may be evaporated by a heater or the like instead of relying on spontaneous evaporation. At this time, if the evaporation rate of the solvent is too high, the aggregation of the sample S tends to be delayed. Therefore, there is a concern that the condensed sample S tends to spread and the thickness of the condensed sample S becomes thin.

FIG. 6 shows means 7 for controlling the rate of forced evaporation of the solvent. The control means 7 includes a pedestal 9 having a heater 8 on its lower surface,
It comprises a sealed container 10 placed on top, and a narrow tube 12 provided with an exhaust control valve 11 is penetrated in the sealed container 10.

According to such a configuration, the sample table 1 is positioned on the gantry 9, a small amount of solution is dropped on the thin film 5 of the sample table 1, and the sample table 1 is covered so as to cover the sample table 1. By mounting the closed vessel 10 on the gantry 9 to generate heat from the heater 8 and controlling the amount of exhaust by the control valve 11, the solvent in the solution evaporates in the presence of saturated evaporation, and The evaporation rate of the sample S is controlled, so that not only the concentration of the sample S is improved but also the contamination of the solution and the condensed sample S with the outside air is prevented.

FIG. 7 shows a sample table 1 of another embodiment used in the method of analyzing infrared reflection. A base 13 made of a fluororesin, which may be a thin film, and a sample S condensed on the base 13 are shown. More specifically, the base 13 is made of a fluororesin that condenses the sample S by the means shown in FIGS. 2 to 4, and transfers and carries the condensed sample S by micro means. The sample supporting surface, which is located in the spectroscopic analysis unit, includes a mirror-finished infrared reflecting member 14.

According to such a configuration, infrared light emitted from the light source 2 is absorbed by the transfer sample S and reflected by the infrared reflecting member 14, and the spectrum of the reflected infrared light is measured by the measuring device 3. Therefore, as compared with the micro-spectroscopic analysis method shown in FIG. 1, there is an advantage that the measurement sensitivity is increased because the fluororesin thin film 5 does not exist on the infrared reflecting surface.

FIG. 8 is a principle diagram for explaining a micro-spectroscopic analysis method by transmission of infrared rays according to the present invention. In this figure, reference numeral 1 denotes a sample table for supporting a sample S;
Is a light source for irradiating the sample S with infrared IR; The spectrum measuring device performs quantitative analysis, qualitative analysis, and the like on the sample based on the measurement information of the transmission spectrum by the measuring device 3.

The beam condensers 17 and 18 are provided to increase the light-collecting efficiency. The beam condensers 17 and 18 are omitted, and a light-condensing lens is arranged in the middle of the optical path incident on the sample S. Even so, an increase in light collection efficiency is achieved.

The sample table 1 in this embodiment is obtained by attaching a thin film 21 made of, for example, a fluorocarbon resin to an infrared transmitting member 20 made of, for example, a KBr crystal. That is, in addition to KBr, a crystal or a film made of an alkali halide material such as NaCl or CaF ₂ can be selected, and preferably, a material having a small deliquescent is selected.

If there is no problem in strength, it is also possible to omit the infrared transmitting member 20 and to configure the sample table 1 only with the fluororesin thin film 21.

FIG. 9 shows a sample table 1 of another embodiment used in the method of analyzing infrared transmission. A base 22 made of a fluororesin, which may be a thin film, and a sample S condensed on the base 22 are shown. An infrared transmitting member 23 for transfer, more specifically, a fluororesin base 22 for condensing the sample S by the means shown in FIGS. An infrared reflecting member 23 such as a crystal or a film of an alkali halide material such as KBr or NaCl, which is located in the spectral analysis section.
Consisting of

According to such a configuration, the infrared light emitted from the light source 2 is absorbed by the transfer sample S and transmitted through the infrared transmitting member 23, and the spectrum of the transmitted infrared light is measured by the measuring device 3.
As compared with the micro-spectroscopic analysis method shown in FIG. 8, since there is no fluororesin thin film 21 in the infrared transmitting portion, there is an advantage that the measurement sensitivity is increased.

The means for applying the fluororesin thin film 5 to the infrared reflecting member 4 or the means for applying the fluororesin thin film 21 to the infrared transmitting member 20 includes coating (dispersion) or fluorine. Means such as sticking of the resin film can be arbitrarily selected.

[0038]

As described above, according to the microspectroscopic analysis method of the present invention, the solvent contained in the solution is evaporated by evaporating the solvent in the solution in a state where diffusion is limited by the fluorine resin having high water repellency. The condensed sample is made to have a small thickness with a small spread, and the condensed sample is subjected to micro-spectroscopic analysis by an infrared reflection method or an absorption method. The thickness can be increased, so that the infrared absorption intensity of the condensed sample is increased. As a result, even if the sample is small and minute, it can be analyzed with high sensitivity by the method of reflection or transmission of infrared light. Was.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a microspectroscopic analysis method using infrared reflection.

FIG. 2 is an explanatory diagram in which a solution is dropped on a sample table.

FIG. 3 is an explanatory view showing a state in which a solvent in a solution is being evaporated.

FIG. 4 is an explanatory diagram showing a condensed state of a sample.

FIG. 5 is an explanatory diagram in which a condensed sample is flattened by pressing.

FIG. 6 is a cross-sectional view of control means for controlling the evaporation rate of a solvent.

FIG. 7 is an explanatory view of a sample table of another embodiment used for the infrared reflection analysis method.

FIG. 8 is a principle diagram of a micro-spectroscopic analysis method by transmission of infrared rays.

FIG. 9 is an explanatory view of a sample table of another embodiment used for the infrared transmission analysis method.

FIG. 10 is a graph showing infrared light transmission characteristics of the sample of the present invention.

FIG. 11 is a graph showing infrared light transmission characteristics of a conventional sample.

[Explanation of symbols]

1 ... Sample stand, 4,14 ... Infrared reflective member, 5,21 ... Fluorine resin thin film, 13,22 ... Fluorine resin base, 2
0, 23: infrared transmitting member, S: sample.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-249736 (JP, A) JP-A-63-1244 (JP, A) JP-A-4-1366738 (JP, A) JP-A 63-244 171342 (JP, A) JP-A-3-226670 (JP, A) JP-A-4-506402 (JP, A) Masahiko Ikeda, "Application of Pinpoint Concentration Method to Micro FT-IR", Polyfile, March 1, 1992 Published by Taiseisha Publishing Co., Ltd., pp. 32-33 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/00-21/61 G01N 1/00-1/34 JICST file (JOIS)

Claims (5)

(57) [Claims] 1. A small amount of a solution in which a sample is contained in a solvent is dropped on a fluororesin thin film attached to an infrared reflecting member of a sample table, and the solvent in the solution is evaporated to condense the sample. Then, the condensed sample is placed on the micro-spectroscopic analysis unit together with the sample table, and the condensed sample pressed and flattened by the pressurizing means is irradiated with infrared rays, and the spectrum reflected from the infrared reflecting member through the condensed sample is measured. A microspectroscopic analysis method characterized by the above-mentioned. 2. The micro-spectroscopic analysis method according to claim 1, wherein the fluororesin thin film is attached to the infrared reflecting member via an infrared transmitting member. 3. A small amount of a solution containing a sample in a solvent is dropped on a base of a fluororesin, the solvent in the solution is evaporated to condense the sample, and the condensed sample is transferred to an infrared reflecting member. Micro-spectroscopic analysis characterized by irradiating the transferred sample with infrared light by placing the transferred sample together with the infrared reflecting member in the micro-spectroscopic analyzer, and measuring the spectrum reflected from the infrared reflecting member through the transferred sample. Method. 4. A small amount of a solution containing a sample in a solvent is dropped on a base of a fluororesin, the solvent in the solution is evaporated to condense the sample, and the condensed sample is transferred to an infrared transmitting member. A micro-spectroscopic analysis method comprising: locating the transferred sample together with the infrared transmitting member in the micro-spectroscopic analysis section, irradiating the transferred sample with infrared light, and measuring the spectrum transmitted through the transferred sample and the infrared transmitting member. . 5. A sample table comprising a fluororesin base and an infrared transmitting member for transferring a sample condensed on the base.