Determination of technetium-99 in soils and radioactive wastes using ICP-MS

Three methods have been used for the determination of Tc-99 in soils and solid radioactive wastes using Tc-99m as a yield monitor. In the method one and three the samples were leached in low concentrated nitric and sulphuric acid. Many contaminants were then co-precipitated with Fe(OH)(3) in alkali media and Tc in the supernatant was separated using anion-exchange extraction chromatography. There were made also some studies how to improve the chemical recovery of Tc-99m in the process of chromatography. In the method two the sample was ashed and then leached in 8 mol dm(-3) HNO3 and after iron precipitation, technetium was separated on chromatographic column. The chemical recovery of Tc-99m was optimized in the process of chromatography and leaching. Typical recoveries of technetium determined with Tc-99m tracer for all these methods were in the range 39%-87%. The Tc-99 activity was measured using proportional low-background beta detector after one week of staying to allow decay of Tc-99m activity. Tc-99 was also determined by the non-radiometric method using inductively coupled plasma mass spectrometer.