Determination of exp 99 Tc in bentonite clay samples using inductively coupled plasma mass spectrometry

A method was developed for the determination of exp 99 Tc at low concentrations in clay samples. The chemical treatment of the samples prior to chemical separation and analysis comprised leaching with sulphuric acid/sodium bromate. After leaching, pertechnetate was extracted with Alamine-336/chloroform and then back-extracted into nitric acid. Detection was carried out using inductively coupled plasma mass spectrometry, ICP-MS. The instrumental detection limit was 0.45 pg/mL, which corresponds to 0.28 mBq/mL. With the use of a desolvating nebuliser, the detection limit was lowered by about a factor of five. The results were compared with a method using radiometric detection.