Inductively coupled plasma-mass spectrometric (ICP-MS) analysis of silicate rocks and minerals

Abstract

The accurate measurement of low levels of trace elements is now necessary in most petrological studies. In this paper, we present the methods used in our laboratory ("Collectif interinstitutionnel de géochimie instrumentale") to analyse simultaneously, with the ICP-MS instrument, 26 trace elements in silicate rocks and minerals. Whole-rocks are prepared using a lithium metaborate fusion in order to assure dissolution of resistant mineral phases, whereas mineral separates (plagioclases, pyroxenes, apatites) are prepared using an open acid digestion. Calibration of the ICP-MS is made with international reference materials for whole-rocks and with synthetic aqueous solutions for mineral separates. The accuracy of the data as well as limits of quantification (LOQ) vary among elements but are usually very good (accuracy better than 6%, LOQ usually below 1 microg/g in solids). Combination of XRF and ICP-MS capabilities enables us to determine 38 elements (major and trace) on a routine basis.