The Cosmosil 5C18-MS-II column,
taking advantage of a new end capping treatment can replace the
Cosmosil 5C18-MS. The silica gel
is end capped with polar groups for shielding effect, based on the
chemical property of the packed silica gel to draw highly polar
components from the mobile phase. As a result, the new end capping
provides improved peak shape for basic compounds. The absorption
of the silica gel is controlled because it does not interact with
N atoms, therefore suitable for the separation of chelating
compounds. Another advantage is that the 5C18-MS-II
has similar retention characteristics to the 5C18-MS
series: the HPLC conditions for the 5C18-MS
are applicable to the newly developed column, 5C18-MS-II.
Material characteristics
COSMOSIL
5C18-MS-II
Silica gel
high purity porous spherical
silica
Average particle size
5µm
Average pore size
approx. 120Å
Specific surface area
approx. 300m2/g
Stationary phase
monomeric type octadecyl group
End capping treatment
near-perfect treatment
Carbon content
approx. 16%
Stability under alkaline
condition
The durability under extremely high pH is greatly improved at the
new COSMOSIL 5C18-MS-II compared
with current COSMOSIL 5C18-MS.
Though it is possible to use under alkaline condition for a
limited time, after long exposure some deterioration may occur.
For long use we recommend pH 7.5 and below. Stability under
alkaline condition
Method: After the indicated length of incubation with the
extremely high pH buffer, the column was washed and the effective
plate number (N) for n-amylbenzene was measured.
The figure above shows the change in N as a function of incubation
time. There is hardly any observed change in MS-II. On the other
hand with MS when 10 hours or more passed rapid deterioration was
observed.
Alkaline solution;0.02M phosphate buffer (pH10.0)
Stability under
alkaline condition
