HR-ICP-MS analyses were performed using a double focusing magnetic sector field HR-ICP-MS Finnigan ELEMENT 2 (Thermo Fisher Scientific, International). A sample introduction system PrepFAST (ESI/Elemental Scientific, International: USA/Germany) was used. Pretreatment/digestion was done using UltraClave (Milestone, Italy). Acidification of samples was performed using ultrapure grade HNO3 SubPur (Milestone, Italy) to avoid adsorption of ions to the walls of the vial.