| 摘要 |
<p>PURPOSE:To make possible the spectral measurement of high sensitivity even if the separated component gas is of low concentration by radiating wavelength variable laser to the specimen introduced into an opto-acoustic cell. CONSTITUTION:The effluent components from a gas chromatograph 1 are captured in a trap 5 via valve 3 and channel changeover valve 4. Next, the valve 3 is changed over to a carrier gas generator 2 and the carrier gas is introduced into the trap 5 which has been elevated of temperature, whereby the captured components are introduced into an opto-acoustic cell 7. Next, when the component gas having been introduced into the cell 7 absorbes modulated laser light by the chopper 11 from a wavelength variable laser 10, the absorption energy becomes heat, causing the sound pressure of the cell 7 to change. This change in the sound pressure is detected with a microphone 12, and is amplified with a lock-im amplifier 13, the output whereof is then divided by the output of a laser power meter 14 in a ratio meter 16, thus the concentration of the component may be detected as a function of wavelengths in a recorder 18 with high sensitivity.</p> |
