Sorption and complexation of uranium(VI) and thorium(IV) with reagents Arsenazo III and Arsenazo M on fibrous filled sorbents

The possibility of the highly sensitive sorption-spectrometric determination of Th(IV) and U(VI) in the presence of each other on the solid phase of fibrous anion-exchange materials with Arsenazo M and Arsenazo III was examined. Polyacrylonitrile fiber filled with an exchanger AN-31, ANKB-50, or EDE-10p was used as the solid phase. It was demonstrated that the studied systems allow the selective determination of thorium in the presence of one-to twofold amounts of uranium. On PANV-EDE-10p with immobilized Arsenazo III, the detection limit of thorium in 2–10 M HCl is 0.002 μg/mL, and in 10 M HCl the presence of up to twofold amounts of uranium is permissible. A high sensitivity of the determination of uranium in 2–7 M HCl of 0.005 μg/mL, which has not been reported before, was attained. The time of the analysis of five or six samples is no longer than 20 min.