Basic Structure-Independent Equations of Kinetic Performance of Columns in Liquid Chromatography

The lowest dimensionless plate height (h_min) of the liquid chromatography (LC) column is a subjective metric that cannot be found from measurements of parameters of a column as a separation device and is not suitable for comparison of kinetic performance of differently structured columns. In some cases (monolithic, pillar-array columns), there is no correlation between h_min (as it is currently understood) and the column performance. The same is true for the flow resistance parameter (ϕ). Recently introduced measurable effective diameter and structural quality factor (q_max) of a column are objective replacements for ϕ and h_min. Metric q_max, the maximum of the flow-dependent kinetic performance factor (q), is suitable for comparison of differently structured columns. Structure-independent basic equations binding kinetic performance of LC column with its q and other parameters and operational conditions were developed. It has been shown that previously known and new equations of a column kinetic performance can be derived from the basic ones. An example of using the equations for solving a known practical problem of column selection is provided.