Oscillopolarographic determination of europium(3) in sodium chloride solutions in the presence of rare earths and other metal ions

The possibility of using NaCl solutions for oscillopolarographic determination of europium(3) in the presence of ions of other REE and some metals has been studied. Investigation has been conducted in a NaCl concentration range 0.1-4 M using mercury dropping electrode. A clearly defined wave of europium(3) reduction has been observed. It is shown that the process of reduction is controlled by diffusion. Polarographic characteristics of electrochemical reduction of Eu(3) in NaCl solutions are given. Graphical dependences of the peak potential and the rate constants of Eu(3) electroreduction on NaCl concentration are presented as well as those of peak potential and current density of Eu(3) reduction on pH of the solution. NaCl solutions with concentration 0.1-0.5 M and pH=3 are optimal for oscillopolarographic determination of Eu (3). Yb, Sm, Nd, Pr, La, and Zn do not hinder oscillopolarographic determination of Eu(3) in NaCl solutions. The technique of determining Eu(3) in oxides of Sm and Nd and in a mixture of oxides of REE has been proposed (Yb2O3:Sm2O3:Nd2O3:Pr2O3=1:1:1:1)