These COSMOSIL columns use packing materials with different
alkyl chains such as C8 (octyl),
C4 (butyl) and TMS (trimethyl).
As the length of alkyl chain shortens, the hydrophobic interaction
becomes weaker.
Owing to the near-perfect end capping treatment and very low level
of free silanol compared to the C18
columns, COSMOSIL alkyl-chained columns can be used widely for the
general analysis of compounds including those for which C18
columns produce long retention times.
Material
characteristics
5C8-MS
5C4-MS
5TMS-MS
Silica gel
high purity pherical porous silica
Average particle size
5µm
Averasge pore size
approx. 120Å
Specific surface area
approx. 300m²/g
Stationary phase
octory group
butyl group
trimethyl group
End capping treatment
near-perfect treatment
Carbon content
approx. 10%
approx. 7%
approx. 5%
Behavior of polar compounds
For the analysis of non-polar compounds such as benzene and
toluene, the column shows weaker retention as the length of alkyl
chain becomes shorter.
The retention increases for polar compounds such as acetophenone
and methyl benzoate.
