Spectrographic Determination of Rare Earth Elements Using a Wall-Stabilized Plasma Arc

A wall-stabilized dc arc is used for the determination of rare earth elements (REs). Solutions of REs are mixed with potassium chloride and sprayed in an argon stream into the plasma of the arc. At the optimal excitation conditions, the spectrum of the arc has a very low background and contains no molecular bands in the visible region. Analytical curves and limits of detection for fourteen REs are determined and the matrix effects are studied. The procedure is applied to the determination of REs in a standard phosphate sample.--AA