Florisil activity was examined by dried column chromatography using Rf value of Sudan I for mark. Dried column for standardization of Florisil activity was prepared by the following procedure.
A glass-column (6×200mm), stopped up the end with cotton, was packed, in order, with anhydrous sodium sulfate (in 10mm of height), silica gel admixed with Sudan I (in 5mm of height), and Florisil column to be standardized (in 160mm of height), from the bottom. The column prepared was subjected to chromatography by ascending method using a mixture of ethanel and n-hexane (3: 7)
Florisil activity was tested by the Rf value of color. The method is useful for standardization of activity of Florisil used for cleaning up of samples on analysis of organochlorine insecticides.