Determination of ytterbium, terbium, lutetium and cerium by emission flame spectrometry

The emission spectrometry in nitrous oxide-acetylene flame makes it possible to selectively determine Ce, Tb, Yb, Lu in hydroxide precipitation from technological REE separation and ores after decomposition. A device of the authors' design was used, based on double grating monochromator GDM-1000 (C. Zeiss, Jena) with a spectral band of 7-35 pm. Determination limits of 0.0008 μg ml-1 Yb; 0.2 μg ml-1 Tb; 0.7 μg ml-1 Lu and 15 μg ml-1 Ce were achieved. Calibration plots were found to be linear up to 1000 μg ml-1 for Ce and Lu, up to 100 μg ml-1 for Tb and up to 2 μg ml-1 for Yb. Al, Ti, Th and Zr interfere significantly in 100 μg ml-1 concentrations. The interference can be eliminated with 5-sulfosalicylic acid. Mutual interference of lanthanides or of accompanying macrocomponents was not observed but sometimes an increased flame background must be taken into a account. (author). 7 figs., 3 tabs., 21 refs