The determination of thorium,lanthanum and samarium in cerium(iv) nitrate by activation analysis,with the aid of electrophoretic focussing of ions

Thorium, lanthanum and cerium were determined in ammonium cerium(IV) nitrate. The chemical separation was carried out by electrophoretic focussing of ions (EFI) in a matter of minutes. The small amount of sample possible in this separation technique is the main limit for the sensitivity of the procedure. With an irradiation time of 2 h at a thermal flux of 4·10¹¹ n/cm²/sec, the lower limits are: Th 0.1 μg; La 4·10^-2μg; Sm 5·10^-3μg.