Studying the effect of neodymium oxide/hydroxide species formed in plasma on the analysis of heavy rare earth impurities trace in the pure neodymium oxide using HPLC - Tandem ICP-MS

High-purity rare earth elements are widely used in many fields of the material technology such as in screens, laser media, optical materials (optical isolators) and high-temperature superconductors, etc.. Inductively coupled plasma mass spectrometry (ICP-MS) with the high sensitivity, the low quantifing limit and the ability to simultaneously identify trace or super trace elements, is used to determine the rare earth elements (REE) traces in high purity Nd2O3. However, the determination of REE impurity in high purity Nd2O3 were affected by samples that contain high levels of total dissolved solids, the dissolved matrix can deposit on the interface cone orifices, leading to signal loss and instability. Moreover, the mass spectrometry interference arising from polyatomic ions such as oxide or hydroxide of neodymium in the high Nd matrix also affected the accuracy of analytical results. ICP-MS/MS (Tripquad Agilent 8900) hyphanated HPLC (Agilent 1200) at the Institute for Technology of Radioactive and Rare Elements was used to study the above-mentioned effects. The study resulted in a proposed method to eliminate the effect of neodymium oxide/hydroxide species such as using the internal standard Rh/Re for the measurement on ICP-MS/MS directly or HPLC - ICPMS/ MS using a cation exchange column PRP-X200. The procedure for determining the heavy rare earth impurities such as Tb and Ho in high purity Nd₂O₃ was built by using ICP - MS/MS equipment system.