Determination of rare earth elements in soils and sediments by inductively coupled plasma atomic emission spectrometry after cation-exchange separation

The influence of matrix elements such as Ba, Ca, Fe, K, Na and Ti, on the inductively coupled plasma atomic emission spectrometry determination of the rare earth elements in soils and sediments is investigated and analytical lines with minimal interferences are chosen. The analysis of certified reference materials by two calibration methods (pure rare earth solutions and IAEA-Soil 5) and after cation-exchange proved that calibrations with IAEA-Soil 5 increase the number of accurately determined rare earth elements (REE), permitting the instrumental determination of Ce, Eu, La, Nd, Tb, Yb and Y in soils and some sediments. The cation-exchange procedure permits the determination of 12 REE with very good accuracy (below 10%) and detection limits varying between 0.05 (Eu, Tb, Yb) and 0.5 (Er) mg kg−1.