JPS628041A - Infrared spectroscopic analysis - Google Patents

Abstract

PURPOSE:To make it possible to rapidly and inexpensively analyze a gaseous component, by measuring the infrared absorption spectrum of a specimen by a reflection method using a Fourier transformation infrared spectroscope to a specimen adhering surface. CONSTITUTION:At first, the infrared absorption spectrum of a specimen adhering surface is measured by a reflection method using a Fourier transformation infrared spectroscope. As the reflection method, for example, a high sensitivity reflection method. wherein infrared beam is incident to the specimen adhering surface at a predetermined incident angle through a polarizer and the reflected light from the adhering surface is spectrally analyzed, is used. Next, the spectrally analyzed value obtained from said reflected light is recorded as the sum of the analyzed value only from the surface of a metal plate and the analyzed value from the specimen adhering surface. Therefore, the infrared absorption spectrum obtained by subtracting the former spectrally analyzed value from said analyzed value is measured as the spectrum peculiar to the adhered specimen. By this method, pretreatment prior to analysis becomes perfectly unnecessary and rapid analysis can be performed.

Description

[Detailed Description of the Invention] [Industrial Application Field J] The present invention relates to an infrared spectroscopic analysis method, and more specifically, a method for extremely easily analyzing gaseous, misty, or powdery samples suspended in the atmosphere. Regarding.

[Prior Art] Various gas components are generated when melt-molding and manufacturing various plastic sheets, films, etc., during heat treatment of plastics, or during combustion treatment of various wastes including plastics. These components are thought to be generated by various additives contained in plastics or by thermal decomposition of plastics and additives.

Therefore, it is necessary to quickly analyze these gas components in order to investigate the causes of deterioration and deterioration of physical properties of plastics. Furthermore, rapid and simple analysis of these gas components is important in order to take effective measures to deal with deterioration of the working environment and pollution problems caused by the generation of these gas components.

Conventionally, one of the methods for analyzing these gas components is to collect gas components from the gases generated in the above-mentioned plastic manufacturing and processing processes using a solution collection method, a filter method, etc.
It was necessary to perform pretreatment to concentrate and separate this gas component sample.

[Problems to be Solved by the Invention] In the conventional infrared spectroscopic analysis method, pretreatment of the sample to be analyzed is essential as described above. Therefore, prior to actual measurement, it takes a lot of time and complicated operations to collect the sample, and a special sampling device is also required.

Therefore, in the past, analysis of gas components lacked speed, and the cost required for measurement was unavoidable.

The method of the present invention solves the above-mentioned problems in conventional infrared spectroscopy and aims to provide a method for quickly and inexpensively analyzing gas components.

[Means for solving the problem] As a result of intensive research to achieve the above object, the present inventor has found that by applying the sample collection method described below and the reflection method using a Fourier transform infrared spectrophotometer, discovered that it is possible to omit sample pretreatment prior to actual measurement, and developed the present invention.

That is, in the infrared spectroscopic analysis method of the present invention, a sample floating in the atmosphere is attached to the surface of a metal plate, and the sample is collected using a reflection method using a Fourier transform infrared spectrophotometer. The method is characterized in that the sample is analyzed by measuring the absorption spectrum and measuring the infrared absorption difference spectrum between the sample-attached surface and the metal plate surface.

Suitable metal plates to be used include stainless steel plates, aluminum plates, etc., which have one smooth and glossy surface. Also,
For example, a smooth thin film of metal such as aluminum or gold may be formed on the surface of a glass plate by a known film forming method such as plating or vapor deposition.

The sample to be analyzed may be any one that floats in the air in the form of gas, mist, or powder.

If the sample is in solid or liquid form at room temperature and pressure, it can be directly attached to the metal plate described above.

In addition, if necessary, rubber, acrylic, silicone, or even rosin may be applied to the surface of the metal plate.

A plate coated with an adhesive layer containing a tackifying resin such as rosin ester can also be used as a sample collection plate.

However, it is difficult to attach a sample that is in a gaseous state at room temperature and pressure to the surface of a metal plate.
For example, a thin gas adsorption layer such as an inorganic adsorbent such as activated alumina, silica gel, activated carbon, or bentonite; or an organic adsorbent such as starch, filter paper, or ion exchange resin may be formed on the surface of a metal plate for sample collection. By doing so, the sample can be effectively attached to the surface.

Next, the infrared absorption spectrum of this sample-attached surface is measured. For measurement, a reflection method is applied using a Fourier transform spectrophotometer that has a built-in computer and performs Fourier transform operations on the obtained data.

The reflection method includes: 1) a high-sensitivity reflection method in which an infrared beam is incident on the sample MWB at a predetermined angle of incidence through a polarizer, and the spectrum of the reflected light from the attached surface is analyzed; The total internal reflection method is applied, in which the sample adhesion surface and the surface of the reflector are made to face each other or through a prism, and an infrared beam is incident on the prism, and the total reflection light is repeatedly totally reflected within the prism and the spectrum is analyzed. Ru. Among these methods, the high-sensitivity reflection method (2) is a preferred method.

The spectral analysis value obtained from this reflected light is recorded as the sum of the analysis value from only the metal plate surface (which may include an adhesive layer or adsorption layer) and the analysis value from the attached sample surface. Therefore, the infrared absorption difference spectrum obtained by subtracting the former spectrum analysis value from this analysis value will be measured as a spectrum specific to the adhered sample.

Therefore, after measuring the infrared absorption spectrum of the surface to which the sample is attached, the infrared absorption spectrum of the surface of the metal plate to which no sample is attached is subtracted using a computer built in the photometer, and the analysis results of the sample are obtained. The analysis of the sample is completed by measuring the infrared absorption difference spectrum that displays .

[Examples of the Invention] Example Commercially available polypropylene resin pellets were extrusion-molded using a T-tie extrusion device (extruder diameter: 50 mm, die: 411,400 ts) to produce a sheet with a thickness of 3 mm. At this time, smoke was observed at the exit of the die.

A stainless steel plate whose surface had been cleaned with acetone was held in this smoking area for 1 hour to allow the fuming substance to adhere to the surface of the steel plate.

The obtained sample plate was set in a Fourier transform infrared spectrophotometer (JIR-40 manufactured by JEOL Ltd., resolution 4.0 cm', number of integrations 200 times), and the infrared absorption spectrum was measured using a high-sensitivity reflectance method. It was measured.

The infrared absorption spectrum of the surface of the stainless steel plate before being held at the smoking point was measured in advance, and this was subtracted from the sample surface spectrum to measure the infrared absorption difference spectrum.

From Figure 0, which shows this in a diagram, it was found that the smoke-producing substance was a higher fatty acid.

[Effects of the Invention] As is clear from the above explanation, the method of the present invention has the following advantages: (1) Sample collection is extremely easy and there are no restrictions;
■No pretreatment is required prior to actual analysis. ■Therefore, it has great industrial value as it allows for quick analysis. In particular, gas components and mist generated during the manufacturing process of various plastics.

It is highly practical as an analysis method for quickly analyzing fine particles and developing countermeasures.

[Brief explanation of the drawing]

The figure is a diagram illustrating infrared absorption difference spectra in Examples.

Claims (1)

[Claims] 1. A sample floating in the atmosphere is attached to the surface of a metal plate and collected, and the infrared absorption spectrum of the sample is measured by a reflection method using a Fourier transform infrared spectrophotometer on the sample attachment surface. An infrared spectroscopic analysis method is characterized in that the sample is analyzed by measuring the infrared absorption difference spectrum between the sample-attached surface and the metal plate surface. 2. The infrared spectroscopic analysis method according to claim 1, wherein the surface of the metal plate is coated with an adhesive layer. 3. The infrared spectroscopic analysis method according to claim 1, wherein the metal plate surface is coated with a thin gas adsorption layer.