Preconcentration and neutron activation analysis of thorium and uranium in natural waters

Uranium and thorium were analyzed in commercial bottled waters and in fresh waters, such as tap water, by neutron activation analysis. The analysis was applied after a preconcentration step from a batch of 1-3 dm(3) water under investigation. The adsorption was performed in the presence of a small amount (about 1 g) of an adsorber derived from the salt of alpha-hydroxyquinoline and benzilic (diphenylglycolic) acid, adsorbed onto charcoal. The preconcentration method has shown to be rapid and reliable. The overall method was set in order to have an alternative method of comparison with other different methods of analysis. The proposed method may be applied to different fresh water samples.