Vapor Generation of Rare-Earth Elements via Reaction with Tetrahydroborate: Chemical Identities and Mechanisms of Formation

This technical note reports for the first time the simultaneous vapor generation of 16 rare-earth elements (REEs) via reaction with sodium tetrahydroborate (THB). Significant improvement in REE vapor generation efficiency was discovered in the presence of arsenazo III (ARS). Subsequent to a critical evaluation on the impacts of various experimental variables, including the concentrations of acids, THB, and ARS, blank-limited (reagent contamination and impurity from ARS) detection limits (LODs) in the range of 0.004–0.15 μg L–1 were achieved based on three times the standard deviation of the method blank by the proposed vapor generation inductively coupled plasma mass spectrometry (ICP-MS). The nature of released REE species was studied by various approaches and identified to be REE nanoparticles and REE-ARS chelates; a dual-route mechanism for the vapor generation of REEs was thereby proposed.