ANALYSIS OF SOLIDS BY LASER ABLATION INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY (LA-ICP-MS) .1. MATCHING WITH A GLASS MATRIX

The possibility of quantitative elemental analysis of solids by laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS) has been investigated. The solids were mixed with a flux and fused to a glass bead so that a similar matrix composition would be obtained for the different samples (matrix matching), and an internal standard could be added. Strontium, present in the flux materials, was found to be suitable as the internal standard. Two major problems were experienced in the analysis: memory effects and interference from polyatomic ions. The memory effects were probably due to deposits of particles in the transfer tubes between the laser ablation cell and the ICP torch. At masses below 80 m/z, strong interferences from polyatomic ions caused serious problems in the quantification and, for elements studied in that mass region, detection limits were poor. The technique was further applied more specifically to the determination of rare earth elements in geological materials, for which detection limits varied from 0.02 to 3 mg/kg. Quantitative analysis, independent of the kind of sample material, proved possible.