Abstract

A method was developed for the determination of trace and ultratrace amounts of REE, Cd, In, Tl, Th, Nb, Ta, Zr and Hf in soils and sediments. With NaOH–Na₂O₂ as the flux, Ti(OH)₄–Fe(OH)₃ co-precipitation as the preconcentration technique and inductively coupled plasma mass spectrometry (ICP-MS) for measurement, the whole procedure was concise and suitable for batch analysis of multi-element solutions. An investigation was carried out of the Ti(OH)₄–Fe(OH)₃ co-precipitation system, and the results obtained showed that the natural situation of Ti tightly coexisting with Nb, Ta, Zr and Hf in geological samples plays a very important role in the complete co-precipitation of the four elements. The accuracy of this procedure was established using six Chinese soil and sediment certified reference materials (GSS and GSD), and the relative errors between the found and certified values were mostly below 10%.