Dual-stage matrix elimination-ICP-MS methodology for REEs profiling in barite-associated ores

Background

The quantification of rare earth elements (REEs) in barite-associated geological samples is complicated by persistent matrix effects from coexisting elements and overlapping mass spectral interferences. These analytical challenges are particularly pronounced in samples containing high concentrations of light REEs (LREEs), which induce spectral overlaps on heavy REEs (HREEs) during inductively coupled plasma mass spectrometry (ICP-MS) measurements.

Results

A two-stage precipitation protocol achieved separation efficiencies exceeding 93.0 % for nine matrix elements (Ba, Na, Sr, etc.), while subsequent 717-type anionic resin chromatography enabled group separation of REEs. Sequential elution with methanol-nitric acid (3.40 mol/L, 7:3 v/v) and 0.20 mol/L nitric acid solutions yielded distinct recovery profiles: HREEs (Eu–Lu) showed >90.0 % recovery in the first elution phase, followed by quantitative isolation of LREEs (La, Ce, Pr) in the second phase. The method was verified by using certified reference materials (GBW07892, GBW07893), and the determination results were consistent with the certified values. The application to three natural barite-associated REE ores was also realized.

Significance

This methodology resolves critical limitations in REE analysis through matrix element elimination and controlled LREE/HREE fractionation. The demonstrated 90.2–106.9 % recovery range across all REEs confirms operational robustness, while successful implementation in certified materials and field samples establishes reliability for geochemical characterization. The elution sequence optimization provides a template for analyzing REEs in barite-associated ores.