Spectrographic Determination of Trace Amounts of Rare Earths. I. Analysis of Lanthanum and Yttrium by the Powder Sifting Method

Abstract

A new simplified method for the determination of trace amounts of rare earths in HCl and sodium versenate solutions has been developed. The solutions of the rare earths, La and Y, and of the internal standard (palladium chloride) were evaporated on graphite powder, and this was mixed with NH₄NO₃. Vertically arranged copper electrodes were used with the sifter electrode as the cathode and a flat surfaced copper rod as the anode. A generator was used as excitation source which combines a dc arc with a Feussner spark. The excitation was effected in an atmosphere of 20% argon and 80% oxygen. The detection limit obtained for the two elements, La and Y, as chlorides and as versenates was 0 2 and 0.1 μg per sample respectively. The usual range of the method was from 0.5 to 10 μg/ml for either solution and element. The average coefficient of variation for this method was ±13 7%. The mutual interferences of both elements have been considered as negligible for this range of concentration investigated