The most of the RP HPLC columns have silica based support material, I want to know what are the other kind of material that can be used as innert support, for e.g. Alumina??
Silica is the most common support material because it is not expensive, can be prepared with high purity and controlled sizes, and is stable under high pressure. Also, the surface chemistry of silica allows us to easily bond a stationary phase, like C18, to the surface.
The other common supports are:
1. polymers, based on polystyrene-divinylbenzene. These are also used for ion exchange columns, but there are some reversed phase columns. They have a very high carbon content, and thus are very retentive. However, they do not have high efficiency, and are not stable under high pressure.
2. zirconia can also be used. It has different surface chemistry than silica but is stable under high pressure and will not degrade at high pH like silica. These columns are manufactured by Zirchrom (www.zirchrom.com). They are more expensive than silica.
3. Titania and alumina have also been used , but they are not very popular.
4. Hybrid support from Waters is also available. It is a combination of silica and ethylene segments. It is reported to be very stable to chemical degradation. Search for BEH on www.waters.com.