Direct Determination of Rare Earth Elements in REE Ores Using Microwave Plasma Torch Coupled with Quadrupole Mass Spectrometry

Abstract

With the widespread application of rare earth elements analysis, the development of rapid detection technology of rare earth elements has increasingly become a necessity within the industry. Microwave Plasma Torch (MPT) as the ion source and Quadrupole Mass Spectrometry (QMS) as the mass analyzer to develop a method for fast detection of rare earth elements (REEs) in water and ore samples has been developed and discussed in this paper. With the MPT-QMS method, for elements Y, La, Ce, Nd, Eu in water samples, the limits of detection (LODs) are 11.0-60.5 μg/L, and the linear ranges are 50-1000 μg/L. When analyzing ore samples, the samples were firstly digested by acid solution and the sample solution formed an aerosol, which was then cooled to keep it dry. The aerosol entered the plasma by the centre tube of the MPT and formed REE ions. These ions enter the QMS, and concentrations of REE elements can be quantitatively determined. Repeated analyses of the same sample by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) yield similar results, indicating that the semi-quantitative analyses of MPT-QMS are precise and reliable. Therefore, MPT coupled with QMS is suitable for portable, rapid analysis of metal elements in water and can be used in the field of in situ quality monitoring of environmental and drinking water.

Keywords

• microwave plasma torch
• plasma mass spectrometry
• rare earth element
• on-line determination