Simultaneous determination of rare earth elements by using substoichiometric separation of lanthanium

An analytical method for the simultaneous determination of rare earth elements by using substoichiometry with two chelating agents, a complexon and an extracting agent, is proposed. The principle of the method is that the element which has the lowest stability constant with the complexon is separated substoichiometrically, while other elements which have higher stability constants are separated quantitatively by a single extraction. This method was applied to neutron activation analysis of rare earth elements. Lanthanum, europium and terbium in orchard leaves were determined simultaneously by using substoichiometric separation with DTPA and TTA.