Division 4.12 Preparation of working standard solutions (2,5, 5,0, 7,5, 10,0 and 20,0 g/L)F1F2

Dilute the stock solution, 20 g/l (4.11) appropriately with a 5 % vol. alcohol solution (4.10) to give five working standards of 2,5, 5,0, 7,5, 10,0 and 20,0 g/l. Filter with a filter of a pore size less than or equal to 0,45 μm (5.3).