Analysis of Rare Earth Elements in Granite and Sandstone by HR ICP-OES Application Note · PlasmaQuant 9100 Elite

Introduction

Quantification of rare earth elements (REE) in geological materials by ICP-OES is one of the most challenging analytical routines. Often containing large amounts of alumina and silica, sulfur and refractory metals, etc., the high matrix contents of digested samples require for exceptional plasma robustness, in particular when trace levels of REE ought to be detected and sample dilution has to be avoided. The vast number of emission lines arising from both matrix and rare earth elements further adds to the complexity, which can be resolved by high spectral resolution only.

This application note describes a method for the analysis of two geological reference materials for granite (GSR-1) and sandstone (GSR-4) for its rare earth constituents including Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, and Yb by high-resolution Array ICP-OES on a PlasmaQuant 9100 Elite equipped with HF Kit.

Interference-free analysis in both granite and sandstone was possible for most REE elements thanks to the unique resolving power of the high-resolution optics of the PlasmaQuant 9100 Elite. Prominent spectral interferences from cerium, erbium, iron, and neodymium on sensitive emission lines of dysprosium, erbium, lanthanum, and samarium were successfully corrected by the CSI-Software Tool. Excellent agreement with the certified values and quality RSD values were obtained for granite (GSR-1) and sandstone (GSR-2). Matrix-specific detection limits are given.