High-sensitivity method of radio gas chromatography for 3H- and 14C-labelled compounds

Abstract

Water and carbon dioxide produced by the flame ionisation detector (FID) of a gas chromatograph can be trapped very efficiently into an absorbing fluid using the gas absorption cell described here. 3H2O, 14CO2, or both, if present in the FID effluent, can then be estimated using liquid scintillation counting. If desired, it is possible to differentiate 3H and 14C by chemical separation of the 3H2O and 14CO2 or by dual label counting. The basic apparatus described can be constructed cheaply, and it is possible to automate it. The method is extremely sensitive and can be used to detect below 100 dpm injected per peak. © 1977.