METHOD AND APPARATUS FOR MEASURING STABLE ISOTOPE

摘要

PURPOSE:To measure a stable isotope quickly with a high sensitivity by converting a sample containing a stable isotope into a compound suitable for a laser infrared spectroscope to measure the absorption of a laser light by optoacoustic spectroscope. CONSTITUTION:A sample containing a stable isotope is separated with a sample separator 10 such as gas chromatograph and undergoes decompositions by oxidation and hydrogenation with a pretreating device 20 to be converted into a compound suitable for a laser infrared spectroscope. A laser infrared spectroscope 30 is based on the theory that absorption occurs in a utterly different oscillation ray in a molecule labeled by a different isotope. Light coming from a laser discharge tube 31 is incident into a sample cell 34 and absorbed passing through a chopper 33 to increase the pressure in the cell 34. Then, it is detected with a microphone 35 and recorded on a recorder 37 through a lockin amplifier 36.