Evaluation of Packed Columns

The column efficiency should be tested immediately after packing and at regular intervals during use to monitor any deterioration. The preferred method for determining the efficiency of a packed column is using the height equivalent to a theoretical plate (HETP) and the asymmetry factor (AS ). The HETP and As values are determined by applying a sample such as 2 % acetone or 1 M NaCl to the packed column. A sample volume of approximately 1.5 % of the column volume and a flow velocity of 30 cm/h will give the optimal results.