Simultaneous determination of some rare-earth elements by derivative fluorimetry and use of the Kalman filter

A procedure for the simultaneous determination of dysprosium, europium, samarium and terbium by laser-induced derivative fluorimetry is described. The method is based on the use of 1 x 10(-4)M hexafluoroacetylacetone (HFA) and 2 x 10(-4)M tri-n-octylphosphine oxide (TOPO) as ligands in aqueous solution at pH 3. The first-derivative and Kalman-filter techniques were used for background correction and reduction of interference. The effects of foreign ions were investigated. The procedure is satisfactory for the simultaneous determination of these four lanthanides.