It was taken an aliquot of 3 mL from the 10 mL solution 3 mol L-1 HNO3 eluted of the column. Measurements of 59Ni were performed with Ultra-LEGe Detector (GUL) with a
cryostat window of Beryllium low energy y-detector containing an active area of 100 mm2, and resolution less than 150 eV (FWHM) at 5.9 keV, from Canberra Industries (USA).

2.3.1 Determination of 63Ni by LSC

It was taken an aliquot of 3 mL collected in a scintillation vial from the 10 mL solution 3 mol L-1 HNO3 eluted of the column,. It was added 17 mL of the scintillation cocktail and the vial was shaken vigorously. Before counting, in order of minimizing luminescence interferences, the vial was stored in the dark for 24 hours.

In order to calibrate the counter and to determine the counting conditions, it was prepared a 63Ni standard solution and a blank solution, in the same conditions of the sample. The counting conditions set up were a time of counting of 60 minutes and a channel interval of 50-400.