To discriminate the sort of a sample by infrared absorption spectrum measurement with a small quantity of a sample with good repeatability by irradiating infrared rays on thermally decomposed product gas, and detecting infrared rays selectively absorbed by the decomposed product gas.
A sample 1 inserted in a sample holder 22 is heated and thermally decomposed by an electric furnace 20, provided surrounding a pipe 21, so as to generate decomposed product gas. The generated cracked product gas is led into a hollow cylindrical body 30 by carrier gas such as nitrogen or argon through a tube 32. Infrared rays are irradiated on cracked product gas, led into a gas cell 3 immediately after being in a thermal decomposing furnace 2, by a light source 4 provided facing a window 33, and infrared rays selectively absorbed by the decomposed product gas are detected by a detector 5 provided facing a window 34, thus measuring the infrared absorption spectrum of the sample.
YAMADA TAKAO
MIYAKE TOMOKO
