For the determination of trace elements in neutron irradiated, selenium by gamma-ray spectrometry the separation of the matrix
activity is often necessary. In model experiments the decontamination of cation and anion impurities from the matrix solution
was investigated by the counter current ion migration. After a processing of 3 hrs the trace activities of Co, Cr, Ga, Na
and Zn were decontaminated from Se with a factor of >103. For the trace elements As and Te representing the anionic constituents, a decontamination factor of 3·102 was obtained.