The criteria for preparative separations are very similar to those influencing analytical LC.
Economic considerations become more important, they are governed by four factors:
1: Resolution — optimizing the separation between the peak of interest without compromising product purity.
2: Loadability — which is affected by particle pore size and available surface area (the smaller the pore size, the larger the surface area). Application of smaller pore sizes is limited by the range of the materials molecular weight undergoing separation and purification.
3: Chemical Stability — since the lifetime of a column is often dependent on the silica's chemical stability, conditions of use are very important.
4: Physical Stability — the robustness of a silica will determine how many times a material can be repacked into a column.