Dissolution of geological material with orthophosphoric acid for major-element determination by flame atomic-absorption spectroscopy and inductively-coupled plasma atomic-emission spectroscopy

An analytical procedure has been developed for the determination of major elements in geological material by both flame atomic-absorption spectrometry and inductively-coupled plasma atomic-emission spectrometry. Condensed phosphoric acid was used for the decomposition of 70 natural minerals containing sulphide, oxide, silicate or carbonate constituents. The results were compared with those obtained when a perchloric acid and orthophosphoric acid mixture was used for the decomposition, to ensure dissolution of even the most acid-resistant minerals. The procedure can be applied to rocks, ores, soils, slags and refractory material as a means of rapid and complete dissolution for the analysis of even the most insoluble material.