Rapid determination of multi-elements in geochemical samples by microwave acid digestion ICP-AES

A method involving chemical decomposition and analysis using microwave acid digestion and inductively coupled plasma atomic emission spectrometry (ICP -AES) is proposed for the rapid determination of multi-elements in geochemi cal samples. Samples of less than 0.3 g were placed in a Teflon pressure ve ssel, to which 3 mi each of HNO3 and HClO4 were added. The vessel was seale d and irradiated under stepwise stages: 1 min at 250 W, 1 min at 0 W, 5 min at 250 W, 5 min at 400 W and 10 min at 650 W. The vessel was cooled fbr 30 min in a water bath. The vessel was carefully opened and 4 mi of HF was ad ded. Irradiation was repeated once again under another set of stepwise stag es: 1 min at 250 W, 1 min at 0 W, 5 min at 250 W, 5 min at 400 W, 10 min at 650 W and 30 min at 500 W. After cooling, the acid solution was evaporated down to several mi using an acid recovery module, and then to drl ness in a Teflon dish. The residue was dissolved in 1.25 mi of 12 M HCl rind dilute d with pure water in a 25 mi Teflon volumetric flask. The entire procedure took less than ii hours, including 2.5 to 4.0 hours digestion. Thirty eleme nts in soil, aerosols and marine sediment were determined by; ICP-XES. The analytical results were in good agreement with reference values for the sam ple material.