Division 6.5.5

Centrifuge the closed flask for one to five minutes at a rotational frequency of 500 to 600 rev min^-1 (5.2.). If a centrifuge is not available (see note to 5.2.) allow the closed flask to stand in the rack (5.7.) for at least 30 minutes until the supernatant layer is clear and distinctly separated from the aqueous layer. If necessary, cool the flask in running water.