Determination of technetium-99 in biological marine samples

The technique proposed here is simple to perform and enables several samples to be processed simultaneously. This is mainly because a dry method is used for the destruction of the organic matter and because the chemical processing involved requires only simple operations -co-precipitation and ion exchange on resin. Up to 100 g dry product were processed and a determination limit of 0.04 pCi was obtained as a result. The mean chemical yield was estimated at 94% for 10 g dry product and 81% for larger amounts (50-100 g). The selectivity of the separation was satisfactory. The decontamination factor for ruthenium was 135, and its presence can be assessed, at the time of measuring, by using an aluminium screen of about 50 mg.cm-2. Technetium-99 was characterized by absorption through an aluminium screen of known surface density. (author)