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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

A carrier distillation method has been applied for quantitative determination of trace amounts of rare earths in hydrochloric acid solution evaporated on graphite matrix. The method can be applied to the analysis of all rare earth elements. The detection limit obtained for individual elements was from 0.02 to 0.16 μg per sample (except for Yb it was 0.0008 μg per sample). The deviations of the position of the analytical curves for the individual rare earth elements have been investigated as they are affected by addition of all other rare earth elements in concentrations at the upper limit of the procedure. It was established that the influence of additional elements is different for the various elements and for the different lines of the same element. The interpolation error for maximal difference in composition between the sample and spectrographic standards has been calculated.

A method for the spectrographic determination of trace amounts of Eu, La, Y, Nd, Pr, and Sm in the 5 N HCl solution has been developed. The solution is evaporated on graphite powder and excited in the craters of graphite electrodes in a dc arc using the carrier distillation method CsF is used as the carrier. Excitation is made in the special atmosphere of 80% oxygen and 20% argon. For Y and La, the range of determination is from 0.25 to 10 μg/ml and for Eu, Nd, Pr, and Sm the range is from 0 5 to 20 μ g/ml. The average coefficient of variation amounts to ± 10%. It has been found that in the investigated concentration range the influence of some rare earth elements on excitation of the others is negligible This method can be applied also to the analysis of other rare earth elements