Radioimpurity identification by retention index in tritium labeling

Retention indexes (RI's) on SE-30 and Carbowax 20M columns are characteristic and can be used for identification purposes. A method for predicting RI on the basis of the number of atoms and contributions from substituents and functional groups is discussed. This method establishes a structure retention index relationship (SRIR), capable of relating structure to RI and is useful for suggesting structure to match with radioactive peaks. Examples of labeled side products tentatively identified in this manner are given.