3. Consideration for scaling up

Selection guide for the preparative scale

When scaling up, column size and particle size of the packing materials should be selected depending on the amount of material and the required purity of the target molecules. If flow rate and sample loading amount are increased proportionally to the ratio of the column cross sectional areas whole keeping both column length and particle size of the packing materials, both the same resolution and the same column pressure can be maintained before and after scaling up. Examples of typical scaling up studies are indicated by the arrow in the table below.

• Guide for selection devices and columns

Selection of the particle size

Smaller particle sizes lead to higher column efficiencies, but at a higher cost. In addition the systems with higher pressure limit are required due to high backpressure. Smaller particle sizes are effective for higher resolution when the separation of the target peak and the close peak is insufficient. On the other hand, larger particle sizes lead to lower column efficiencies, but at a lower costs for packing materials and at a lower column operating pressure.