Determination of Ultratrace Impurities in High Purity Tantalum Materials by On-line Anion Exchange Matrix Separation and Inductively Coupled Plasma Mass Spectrometry

摘要

Ultratrace metal impurities (Be, Al, Ti, Cr, Ni, Nb, Mo, Sn, W, Th, and U) in high purity tantalum metal, tantalum(V) oxide, and tantalum pentaethoxide were determined by a combined system of flow injection with an anion exchange column and inductively coupled plasma mass spectrometry (ICP-MS). In the present combined system, the on-line matrix separation and multielement determination of impurity elements could be performed. When 2 M HCl/0.1 M HF mixed solution and 1 M HNO3/0.1 M HF mixed solution were used as the carrier solutions, Be, Al, and Ti for the former, and Cr, Ni, Nb, Mo, Sn, W, Th, and U for the latter were eluted from the column without any tantalum matrix. The detection limits (3σ) of analyte elements were in the range over 0.003 - 0.14 ng/ml as the sample solution basis. The present method was applied to the determination of metal impurities in high purity tantalum materials. The concentrations of Be, Ti, Mo, Sn, Th, and U were at the ng/g level, while those of other elements were in the range over the μg/g - ng/g level.