Preparative Chromatography - The Loading Capacity of a Column > Page 2

The Loading Capacity of a Column

The column system that is most commonly employed in preparative chromatography is the axial flow cylindrical column.. Other column systems that are used very effectively in preparative chromatography are radial flow columns, and simulated moving bed columns, but these systems are more complex and require very special and expensive apparatus. In addition, initial work with traditional columns will usually be necessary in order to evaluate the separation problem and thus, justify the necessary expense that is involved with these more sophisticated type of column systems.

It has been shown (see The Plate Theory and Extensions ), that the maximum sample feed volume (Vi) or sample mass (Mi) that can be placed on a cylindrical column is directly proportional to the plate volume of the column:

or:

where K is the distribution coefficient of the solute between the two phases,
(vs) is the volume of stationary phase per plate,
(vm) is the volume of mobile phase per plate,
(n) is the column efficiency,
(Av) is a constant for sample volume,
and (Am) is a constant for sample mass.