Bulk packings

Tips for isolation/purification

Isolation/purification by using chromatography, such as HPLC, is scaled up to the preparative scale, followed by optimization of sample separation on the analytical scale. For scaling up, the particle size of the packing materials and the inner diameter and length of the columns should be selected depending on the total sample volume and specifications of the preparative system. Then, preparation is performed, followed by optimization of the conditions for chromatographic separation and sample loading.

Optimization of sample loading

In preparative purifications, sample loading affects the separation results. Optimized sample loading varies depending on the prioritized parameters. Sample loading sometimes cannot be increased when purity and recovery are prioritized. On the other hand, although high sample loading is suitable when preparation is prioritized, reducibility, purity, and recovery can be low.
Optimization of sample loading depending on the case is important.

Effect of sample loading on purification results

Temperature conditions

band spreading within a column

Preparative purification uses air-conditioned room temperature as the column temperature. When columns are used at other temperatures, the inner diameter of the column is larger, causing a nonuniform internal temperature, and poor peak shape and peak splitting are caused by nonuniform flow of the sample. Therefore, verifying the temperature dependence of resolution and peak shape on the analytical scale and selecting separation conditions at room temperature, as far as possible, enables high-efficiency preparation to be realized.

Stacked injection

Overlapping impurities except for objective compounds by continuous sample injection in preparation can save time and solvent volume. Stacked injection dramatically improves productivity.