Scandium analysis in silicon-containing minerals by inductively coupled plasma tandem mass spectrometry

This article reports on the development of a new method for the accurate and precise determination of the amount of scandium, Sc, in silicon-containing minerals, based on the use of tandem quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS). The tandem quadrupole instrument enables new mass filtering configurations, which can reduce polyatomic interferences during the determination of Sc in mineral matrices. He and O-2 were used and compared as collision and reaction gases for the removal of interferences at m/z 45 and 61. Using helium gas was ineffective to overcome all of the spectral interferences observed at m/z 45 and particularly for Si-based interferences. However, conversion of Sc+ ions into ScO+ ions (after bombardment with O-2 in the octopole reaction system coupled with the use of the instrument in MS/MS mass-shift mode) provided interference-free conditions and sufficiently low limits of detection, down to 3 ng L-1, to accurately detect Sc. The accuracy of the proposed methodology was assessed by analyzing five different reference materials (BX-N, OKA-2, NIM-L SY-3 and GH). (C) 2016 Elsevier B.V. All rights reserved.