Solvent extraction studies using tetracycline as a complexing agent Pt. 15

A chemical procedure was developed for the separation of U, Th, Fe, Sc, Na, Ta and Mo, which interfere in neutron activation analysis of the lanthanide elements in rocks. This method is based on the extraction of interferences before irradiation of the samples, using a solution of tetracycline in benzyl alcohol. The lanthanide elements remain in the aqueous phase and are coprecipitated with calcium oxalate or ferric hydroxide for irradiation and subsequent determination by gamma-ray spectrometry. Conditions for the separation of these interferences are examined determining the extraction curves. The procedure was used in the determination of lanthanide elements in three international geological standards for evaluation of accuracy, reproducibility and sensitivity. (author) 14 refs.; 2 figs.; 4 tabs