Accurately weigh 1 g of homogenized sample and mix thoroughly with 1 ml of sulphuric acid (4.13), 15 ml of acetone (4.12) and 8 g of Celite AW (4.14). Air dry the mixture for 30 minutes on a steam bath, then dry for one-and-a-half hours in a ventilated oven. Cool, finely powder the residue and transfer to a glass column.
Elute with ethyl acetate (4.1) and collect 100 ml. Add 2 ml of internal standard solution (solution C) (6.1.2).
Because of the wide range of product types in which hexachlorophene could be present, it is important to first check recovery of hexachlorophene from the sample by this procedure before recording results. If recoveries are low, modifications, such as change of solvent (benzene instead of ethyl acetate) etc., could be introduced with agreement of the parties concerned.