VDSpher® for Preparative Applications
VDSpher has proven itself not only in the analytical scale, but also for the semi-preparative and preparative HPLC. Customers from all areas of research & development as well as from quality control of research facilities to large enterprises of the chemical and pharmaceutical industry use different VDSpher modifications in order to purify and analyse their substances. The excellent scalability enables a simple switching from small particle diameters (1.8 µm to 5 µm) to larger particle sizes (5 µm, 7 µm, 10 µm, 15 µm, 30 µm and beyond) preferred in semi-preparative and preparative applications.
Some VDSpher Classic modifications are available with a pore diameter of 75 Å. The high surface of these materials of 500 m2/g offers the advantage of very high sample loading, so that time and money can be saved during purification.
All VDSpher Classic & PUR silica gels can be used in the semi-preparative and preparative scale. To achieve the best possible column packing we recommend VDSpher Classic phases especially for columns with 20 mm inner diameter or higher.
The table provides information on the normally available column dimensions. Needless to mention, column lengths other than the ones specified in the Table are available on request.
Column Dimensions for Semi-Preparative and Preparative Applications
| Inner diameter [mm] | Available column lengths [mm] |
|---|---|
| 8.0 | 30 / 40 / 125 / 250 |
| 10.0 | 50 / 100 / 150 / 250 |
| 16.0 | 30 / 60 / 125 / 250 |
| 20.0 | 30 / 50 / 100 / 125 / 150 / 250 |
On request, we would also be glad to offer you preparative HPLC columns with inner diameters of 25 mm, 32 mm, 40 mm, 50 mm and 63 mm.
We naturally offer a refill service for all our preparative and semi-preparative VDSpher columns. This way you can not only save costs, but also be more environment-friendly.
VDSpher® PUR Phases with 7 µm Particle Sizes
We would also like to focus on some VDSpher PUR modifications which are available for selection in a particle size of 7 µm. This particle size represents a valuable compromise between 5 µm and 10 µm: Less pressure than with 5 µm – more plates numbers than 10 µm.
This factor is illustrated by the Table below which compares the three columns of the phase VDSpher PUR 100 C18-E, having different particle sizes: 5 µm, 7 µm, and 10 µm. The analytical column dimension 250 × 4.6 mm was chosen for demonstration purposes. The pressure relations of the columns show: Particle with a diameter of 7 µm causes hardly double the pressure caused by 10 µm, but only about half the pressure caused by a particle size of 5 µm. Hence, the plates numbers of the phase with 7 µm provide a clear gain as compared to a column with 10 µm bulk material.
In brief: Anyone who still has scope in the pressure range for 10 µm, can profit essentially from 7 µm bulk material. But anyone who have to work in the upper pressure range with 5 µm phases, can switch to 7 µm particle diameter without any major compromise in terms of separation.
Comparison of Pressure and Plate Numbers:
VDSpher® PUR 100 C18-E with 5 µm, 7 µm and 10 µm Particle Sizes
| Particle size [µm] | Pressure [bar] | Soil column per meter (Anthracene Peak) |
|---|---|---|
| 5 | 48 | 111000 |
| 7 | 25 | 83000 |
| 10 | 14 | 54000 |
The following phases are normally available in a particle size of 7 µm:
- VDSpher® PUR 100 SIL
- VDSpher® PUR C18-E
- VDSpher® PUR C8-E
- VDSpher® PUR Phenyl-E
- VDSpher® PUR CN