Preparation and analysis of isotopically pure tetratritiated methane

Many difficulties are encountered in the preparation of multilabelled coumpounds, as their purification and analysis for isotopic purity are involved. Another major problem is their self‐radiolysis which can change their composition during storage. This paper describes the preparation of CT4 and the analyses which were carried out in order to check its purity : i.e. the mass spectrometric assay and a new gas chromatographic technique employing as detector an ionization chamber coupled with a vibrating reed electrometer. These analyses confirmed the isotopic purity of the CT4 prepared, the main impurity being CHT3.