All alloy samples were dissolved by

All alloy samples were dissolved by usual HNO3 and HCltreatment [26].Each0.1 gof alloyplacedinto a PTFE beaker was mixed with 10 ml of concentrated HNO3 and 10 ml of concentrated HCl. After heating sample on a hot plate until nearly dryness, the residue was dissolved in water and the volume ®lled up to 100 ml. Rock sample was decomposed by sequential treatment with mixture of HFand HClO4, according to Sulcek and Povondra [27]. An accurately weighed amount of 0.25 g of ®nely powdered rock was placed in a PTFE beaker and moistened with water, followed by the addition of 10 ml of 48% HF and 1 ml of 70% HClO4. After evaporating HClO4 fumes in a sand-bath, the remaining residue was cooled, a further 5 ml of 48% HF was added and the contents of the beaker were again evaporated nearly dryness. The cooled residue was dissolved in 100 ml of water.