In this procedure the sample intake was of 3 g, which were placed in 250 ml Pyrex digestion tubes. First, the pre-digestion step was done at room temperature for 16 h with 28 ml of 37% HCl:70% HNO3 (3:1) mixture
In this procedure thesample intake was of 3 g, which were placed in 250 mlPyrex digestion tubes. First, the pre-digestion step wasdone at room temperature for 16 h with 28 ml of 37%HCl:70% HNO3 (3:1) mixture