Determination of 99Tc in environmental samples by anion exchange and liquid-liquid extraction at controlled valency

A method for collecting ⁹⁹Tc from 200-2-400 1 of sea water by anion exchange has been developed. Further decontamination of ^103.106Ru was achieved by repeated evaporation of RuO₄ from 0.05 M sulphuric acid at 100° C, followed by extraction of TcO^-₄ into 5% triisooctylamine-xylene at controlled valency. ^110mAg was precipitated as AgCl. An average overall radiochemical yield of 70% was found for Tc. Decontamination factors were between 3 10⁵ and 2 10⁷ for Ru and 2 10⁵ for Ag. A method for determining ⁹⁹Tc in seaweed by wet ashing and simple extraction into 5% triisooctylamine-xylene is also presented.