Reversed phase liquid chromatography has been widely used due to
its separation characteristics, high theoretical plate number,
reliable reproducibility and ease of use.
However high performance large-scale columns for preparation and
purification are very expensive and many chromatographers need
less expensive preparation and purification techniques.
The particle sizes that are most generally used for analytical
separations have been 5 and 10µm. However many large scale
separations don't require such a small particle size and 40 or 140µm
sized packing material is sufficient for large scale separations.
The COSMOSIL C18-PREP is
a conventional C18 packing
material based on totally porous spherical silica, which can be
effectively used for medium pressure and open column
chromatography. There are three different particle sizes, as
outlined in the table below.
totally porous spherical silica
Average particle size
Average pore size
Specific surface area
End capping treatment
flash column chromatography
flash or open
Particle size, flow rate and theoretical
Because reversed phase chromatography employs effluents of high
viscosity such as methanol and water, the flow rate is lower than
that of normal phase chromatography which uses effluents of low
viscosity such as hexane and ethyl acetate.