VDSpher® Normal Phases
For the normal phase (NP) chromatography, unmodified as well as several modified silica gels are available. A multiplicity of normal phase separations can be enabled by them. The available VDSpher Classic & PUR normal phase modifications and their physical properties are shown in the appropriate Tables.
Normal Phase Modifications: VDSpher® Classic & PUR
| Phase | Modification | Endcapping | USP Code |
|---|---|---|---|
DAP (2) |
Alkylamine | no | L8 |
SIL (1) |
None | no | L3 |
| Diol | Dihydroxyalkyl | no | L20 |
CN (1) |
Alkylnitrile | yes | L10 |
| CN-SE | Alkylnitrile | yes (special) | L10 |
NH2 (1) |
Alkylamine | no | L8 |
AP (2) |
Alkylamine | no | L8 |
(1) Also available as U-VDSpher PUR Phases for UHPLC.
(2) Also available as VDSpher Flash Phases for flash chromatography.
Especially to be highlighted are the advantages of the chemically modified silica gels, which enable a fast equilibration, reproducible analyses despite fluctuating water content in the mobile phase and a problem-free application of the gradient run.
Depending on the modification, different mechanisms can be used for separation:
- SIL: polar interactions, high silanophilic activity
- Diol: polar interactions, hydrogen bondings, silanophilic activity
- CN: polar interactions, π-π interactions, hydrophobic interactions, very low silanophilic activity
- CN-SE: polar interactions, π-π interactions, hydrophobic interactions, no silanophilic activity
- NH2: polar interactions, hydrophobic interactions, ion exchange, silanophilic activity
- AP: polar interactions, hydrophobic interactions, ion exchange, silanophilic activity
- DAP: polar interactions, hydrophobic interactions, ion exchange, silanophilic activity
Moreover, it must be considered that the silano groups at the surface of the silica gel respond slightly acidic, while amino modifications have an alkaline effect. In contrast, diol and CN are considered as neutral modifications.
Physical Properties: VDSpher® Classic & PUR Normal Phases
| Phase | Available pore sizes [Å] |
Carbon content [%] |
Nitrogen content [%] |
pH range |
|---|---|---|---|---|
| DAP | Classic: 100 |
4.5 | 2.3 |
2 - 7.5 |
| SIL | Classic: 75, 100, 150, 200, 300, 1000 |
0 | 0 | 2 - 8 |
| Diol | Classic & PUR: 100 | 4.5 | 0 | 2 - 8 |
| CN | Classic & PUR: 100 | 6.5 | 1.3 | 2 - 8 |
| CN-SE | PUR: 100, 150 |
100 Å: 7.0 150 Å: 5.0 |
100 Å: 1.5 150 Å: 1.2 |
2 - 9 |
NH2 |
Classic & PUR: 100 | 4.0 | 1.5 | 2 - 7.5 |
| AP | Classic: 100 |
4.2 |
1.5 | 2 - 7.5 |
The available particle sizes can be obtained from our current price list.
VDSpher 100 AP is only available with particle diameter of 15 µm, 30 µm or 55 µm.