Sodium sulfate anhydrous. Defatted cotton wool. Tap the columm between addition of the materials to ensure even packing. Then seal the column with alcohol lamp. Add 200 ml of extracting solvent and shake contents of the flask well by a shaker for 30 min. or blend with a medium speed blender for 3 min.
Filter contents through a folded paper filter into a graduated cylinder.
Take 40 ml of the filtrate and pour into a 250 ml beaker. Add 20 ml of zinc acetate solution, stir, and mix well. Leave for 1 min. Then add 40 ml of 0.1 MH3PO4, stir and mix well, and stand for 5 min. Filter through a folded paper filter into a graduated cylinder.