Soil quality — Dissolution for the determination of total element content — Part 3: Dissolution with hydrofluoric, hydrochloric and nitric acids using pressurised microwave technique
ISO 14869-3:2017 specifies a method for microwave-assisted dissolution of soil samples for determination of total element contents of Al, As, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Se, Sb, Sr, Tl, V, Zn using an acid mixture of nitric acid (HNO3), hydrofluoric acid (HF) and hydrochloric acid (HCl). This method is applicable to all types of soil and soil material. The main field of application is geological and pedological survey. The acid mixture is suitable for total dissolution of element contents in soil (major, minor and trace), but some refractory compounds such as SiO2, TiO2, spinel, Al2O3 or other compounds may remain as a residue. In such a case, the use of alkaline fusion, following ISO 14869‑2, is recommended to determine the true total element content. NOTE 1 In environmental studies, usually, aqua regia extraction is applied using ISO 12914 or ISO 11466. Solutions produced by the microwave method are suitable for analysis, for example, by using atomic absorption spectrometry (FAAS, HGAAS, CVAAS, GFAAS), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS). NOTE 2 Due to the presence of chloride in the digestion solution, limitations for the application of some analytical techniques can occur.