Isotope effects in liquid chromatography of imipramine and desmethylimipramine

The effects of tritium substitution in imipramine (IMI) and N-desmethylimipramine (DMI) on their liquid chromatography are described. Increased elution times for tritiated analogues of IMI and DMI were observed using isocratic reversed-phase HPLC techniques. It was shown that the retention of labelled molecules depends on number and position of the tritium atoms. An explanation of the observed phenomena is offered.