Comparison of performance of INAA, RNAA and ion chromatography for the determination of individual lanthanides

Lanthanides represent an interesting group of elements which are steadily gaining importance in science and in industry. Literature data suggest that they may have a role in regulating cellular processes and also in agriculture enhancing plant growth. Only few instrumental methods like NAA, ICP-OES and ICP-MS have potential for the determination of low levels of all lanthanides, but in practice they often have to be combined with suitable separation/preconcentration methods to achieve maximum number of elements being determined and to assure good accuracy and precision. In this work an attempt has been made to compare the performance of both variants of NAA: purely instrumental activation analysis (INAA) and radiochemical mode (RNAA) with pre- and post-irradiation group separation for the determination of individual lanthanides with the special emphasis on rarely determined elements (Gd, Ho, Er, Tm, Lu). This has been done by the analysis of two reference materials with different matrices viz. biological (CTA-OTL-1) and mineral (CTA-FFA-1). The results are compared with those obtained by ion chromatography (IC) employing the same lanthanide group preseparation scheme as in the case of RNAA.