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

Abstract

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 O2 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 O2 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 3ngL−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).