MICROANALYSIS BY LASER-ABLATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY IN COMPARISON TO SPARK ABLATION OF CERTIFIED AND FOUND MINERALS GALENA, SPHALERITE, AND PYRITE

A double-tandem technique of inductively coupled plasma-atomic emissio n spectrometry (ICP-AES) involving laser ablation for the analysis of compact or briquetted minerals on one hand and spark ablation for the analysis of powders on the other is presented. The technical arrangeme nt, the design of the optimized sample chamber, the evaluation of oper ating conditions, and the test of liquid-solid calibration are describ ed. Both techniques can be used for the determination of elemental com positions of minerals providing a dynamic range from tens of mass-perc ent down to milligrams per kilogram. The objective of this study was t o compare laser ablation (LA)-ICP-AES and spark-ICP-AES with regard to accuracy, precision, and sample turnaround time for multielement anal ysis of the certified minerals galena GF1, sphalerite SF1, and pyrite PS1. A systematic error of smaller than 3% in both techniques and a ra ndom error of smaller than 9 and 5%, respectively, is pointed out. The optimized methods were applied to samples of galena, sphalerite, and pyrite from four deposits each to find fingerprints by different conte nts of major, minor, and trace elements, which characterize the deposi ts. (C) 1994 Academic Press, Inc.