Determination of praseodymium, neodymium, samarium and gadolinium in geological materials by emission flame spectrometry

Emission spectrometry in the nitrous oxide-acetylene flame can be applied to the determination of light rare earth elements (Nd, Pr, Sm, Gd) in hydroxide precipitates after their technological separation or after the decomposition of ores. Using a home-made instrument based on a Zeiss (Jena) GDM-1000 monochromator (spectral bandwidth 7-18 pm), the achieved limits of determination for Pr and Gd, Nd, and Sm were 0.3, 0.2 and 0.03 μg/ml, respectively, and for light rare earth elements in ores, 0.1-0.01%. Calibration plots were linear up to rare earth element concentrations of 100 μg/ml. In this concentration, Al, Ti, Th and Zr interfere, the interference, however, can be eliminated with 5-sulfosalicylic acid. Interfering effect of other lanthanides or macrocomponents was not observed; background correction, however, must be applied in some cases. (author). 9 figs., 3 tabs., 14 refs