Improved determination of technologically critical elements in sediment digests by ICP-MS/MS using N2O as a reaction gas

Abstract

The investigation of technologically critical elements (TCEs) as emerging pollutants is a constantly growing field of environmental research and societal concern. Nevertheless, existing data for most TCEs are still unsatisfactory for an accurate assessment of their potential (eco)toxicological effects on humans and the environment. The limited availability of data mainly results from the technically challenging analysis of selected TCEs. Low concentrations of TCEs in environmental matrices (μg kg⁻¹ or lower) and the associated complex and time-consuming sample preparation pose the greatest challenges. This work aims at developing a new ICP-MS/MS-based multi-elemental approach targeting the analysis of all major TCEs (Sc, Ga, Ge, Nb, In, Te, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Yb, Lu, and Ta) in sediment, which represents one of the most important matrices for environmental research. N₂O is applied as a reaction gas to overcome possible spectral interferences during ICP-MS/MS analysis. The use of N₂O as a reaction gas for ICP-MS/MS analysis enabled higher oxide-product ion yields for many TCEs in comparison to the frequently used O₂ cell gas. Hence, the selectivity and sensitivity of the method were improved. The presented multi-element method using N₂O as a reaction gas achieved LODs between 0.00023 μg L⁻¹ (Eu) and 0.13 μg L⁻¹ (Te) for all analyzed TCEs. Likewise, for all analyzed elements, except for Te, recoveries between 80% and 112% were obtained for at least one of the analyzed reference materials (GBW 07313, GBW 07311, and BCR-2).