Kieselguhr for Chromatography

Kieselguhr for Chromatography Kieselguhr complying with the following test.

Filtration rate Use a chromatography column (25 cm × 10 mm) with a sintered-glass (100) plate and two marks at 10 cm and 20 cm above the plate. Place sufficient of the substance being examined in the column to reach the first mark and fill to the second mark with water. When the first drops begin to flow from the column, fill to the second mark again with water and measure the time required for the first 5 mL to flow from the column. The flow rate is not less than 1 mL per minute. The eluate obtained is colourless.