Trace Element Analysis of Fused Whole‐Rock Glasses by Laser Ablation‐ICP‐MS and PIXE

Abstract

The concentrations of fifty trace elements, including relatively volatile elements and transition metal elements, in fused glasses of Geological Survey of Japan rock reference materials GSJ JR‐2, JA‐1, JA‐2, JB‐1a, JB‐3, JGb‐1 and JF‐1 were determined by particle (proton) induced X‐ray emission (PIXE) and laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS). The fused glasses were prepared by rapid fusion and subsequent quenching in welded platinum capsules and were found to be homogeneous for major elements and for trace elements with concentrations of more than 1 μg g‐1 within the observed precision (± 10% mean) on a 70 μm sampling scale. The values obtained by PIXE and LA‐ICP‐MS for the transition elements (Cr, Mn, Fe, Ni and Cu), the relatively volatile elements (Zn, Ga, Rb and Pb) and the refractory elements (Y, Zr, Nb and Th) with concentrations greater than a few μg g‐1 showed good agreement (within 10 % relative difference). The values for almost all the elements detected at concentrations higher than 1 μg g‐1 as determined by LA‐ICP‐MS also agreed well with the reference values (mean relative difference < ± 10%), except for B and Cu. The good agreement confirmed the appropriateness of the NIST SRM 600 series glass calibration reference material for LA‐ICP‐MS analysis of glasses with variable major‐element compositions for almost all elements. The concentrations of Cu in all the samples were lower than the reference values, which was attributed to adsorption of the transition metals onto the platinum capsule during preparation.