Preparation of Standard Solutions : Pharmaguideline
Aluminium Standard Solution (2 ppm Al): ... Iron Standard Solution (10 ppm Fe): Dissolve 7.022 g of ferrous ammonium sulfate in water containing 25 ml of 1M sulphuric acid and add sufficient water to produce 1000.0 ml. Dilute 1 volume to 100 volumes with water. Contains iron in ferrous state.